JPH09209818A - Fuel properties detector and fuel injection controller for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To consist improvement of starting performance with improvement of durability of fuel properties detection in a detector which detects fuel properties by a rate of change of heater consumptive voltage due to injection fuel, by providing engine starting allowing means which allows the starting of an engine after detection of fuel properties is completed. SOLUTION: In an engine in which a PTC heater 31d is oppositely arranged opposite in the fuel ejecting direction of an injector 22, a microcomputer centering around a CPU 51 starts energization to the PTC heater 31d under a condition that it prohibits the operation of a startor motor 67 so as to prohibit the starting of an engine prior to various control. After the completion of warming up of the PTC heater 31d, fuel of a first time fuel oil consumption is ejected from the injector 22, and a heavy rate due to the heavy component of gasoline is found out on the basis of the rate of change of heater consumptive voltage after fuel injection and the first time fuel oil consumption. After that, the starting of an engine is allowed, and the fuel oil consumption for the future is corrected according to the heavy rate so as to obtain an appropriate fuel oil consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel property detecting device for an engine, in which a heater is provided in a pair in the fuel injection direction of a fuel injection valve, and the fuel property is detected by the amount of change in heater consumption current due to injected fuel. The present invention relates to a fuel injection control device for an engine, which corrects a fuel injection amount based on the fuel property.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open No. 6-123 by the present applicant.
As disclosed in Japanese Patent No. 249, in an engine provided with a heater for promoting vaporization and atomization of injected fuel in a fuel injection direction of a fuel injection valve, first, engine start is prohibited and electricity is supplied to the heater. When the heater warm-up is completed, a unique set amount of fuel with a fixed injection pulse width is injected from the fuel injection valve, and the heater current consumption is detected after a set time has elapsed from the fuel injection, and based on this heater current consumption By detecting the fuel property and allowing the engine to start after the fuel property is detected, the fuel property can be detected without adopting the fuel property detection sensor, and the property of the actually injected fuel is inexpensive. There is known a technique capable of detecting the same and further improving the controllability by correcting the fuel injection amount after the engine start permission based on the detected fuel property.

[0003]

However, in the above-described prior art example, since the fuel is injected by the unique initial fuel injection amount when the heater warm-up is completed, it is not always necessary at the time of starting determined by the conditions at that time. There is an inconvenience that a sufficient amount of fuel is not always injected and a sufficient improvement in startability cannot be obtained.

Further, since the fuel property is simply detected based on the heater current consumption after a lapse of a set time from the fuel injection, the same property is caused by the influence of the drift of the output signal from the sensor which detects the heater current consumption. The fuel consumption value of the heater is not always constant even with the above fuel, and there is a limit to the accurate fuel property detection, and sufficient reliability cannot be expected.

In view of the above circumstances, the present invention makes it possible to improve both the startability and the reliability of fuel property detection at the same time, and after the fuel property is detected, it is always appropriate depending on the fuel property. An object of the present invention is to provide a fuel property detection device and a fuel injection control device for an engine, which can supply a fuel amount to an engine, improve combustibility regardless of the fuel property, and improve exhaust emission. .

[0006]

According to the first aspect of the present invention,
As shown in the basic configuration diagram of FIG. 1, in an engine in which a heater is provided in the fuel injection direction of a fuel injection valve, a start inhibiting means for inhibiting the engine starting, and a heater control for energizing the heater after inhibiting the engine starting Means, a heater warm-up completion judging means for judging whether or not the heater has been warmed up, and after completion of warming-up of the heater, a first fuel injection amount is set based on an engine temperature and a fuel of the first fuel injection amount is set. Initial fuel injection amount setting means for injecting from the fuel injection valve,
A heater consumption current change amount detecting means for detecting a change amount of the heater consumption current due to the initial fuel injection; a fuel property detecting means for detecting a fuel property based on the change amount of the heater consumption current and the initial fuel injection amount; After the property detection is completed,
And an engine start permitting unit for permitting the engine to be started.

According to a second aspect of the present invention, as shown in the basic configuration diagram of FIG. 2, in an engine having a heater provided in the fuel injection direction of the fuel injection valve, a start inhibiting means for inhibiting the engine from starting, and an engine. Heater control means for energizing the heater after the start is prohibited, and first fuel injection start timing setting means for setting the start timing of the first fuel injection before the completion of the warm-up of the heater based on the current consumption of the heater and the time after the start of the heater energization. When the initial fuel injection start timing is reached, an initial fuel injection amount is set based on an engine temperature and an initial fuel injection amount of fuel is injected from the fuel injection valve; Heater consumption current change amount detecting means for detecting a change amount of heater consumption current due to injection,
Fuel property detection means for detecting fuel properties based on the amount of change in heater current consumption and the initial fuel injection amount, heater warm-up completion determination means for determining whether warm-up of the heater is completed, and warm-up of the heater. An engine start permitting means for permitting the engine to be started after the completion of the machine.

According to a third aspect of the present invention, as shown in the basic configuration diagram of FIG. 3, in an engine having a heater arranged in the fuel injection direction of the fuel injection valve, a start inhibition means for inhibiting the engine from starting and an engine. After the start is prohibited, the heater control means for energizing the heater, the heater warm-up completion judging means for judging whether the warm-up of the heater is completed, and the initial fuel injection amount based on the engine temperature after the warm-up of the heater is completed. And a first fuel injection amount setting means for injecting the fuel of the first fuel injection amount from the fuel injection valve, and a heater current consumption change amount detection means for detecting a heater current change amount due to the first fuel injection. Fuel property detection means for detecting a fuel property based on the amount of change in heater current consumption and the initial fuel injection amount, and engine start for permitting engine start after completion of fuel property detection And availability means, characterized in that the fuel injection amount after the engine start permission and a fuel injection quantity setting means for setting correction based on the fuel property.

According to a fourth aspect of the invention, as shown in the basic configuration diagram of FIG. 4, in an engine in which a heater is provided opposite to the fuel injection direction of the fuel injection valve, a start inhibition means for inhibiting the engine start, and an engine. Heater control means for energizing the heater after the start is prohibited, and first fuel injection start timing setting means for setting the start timing of the first fuel injection before the completion of the warm-up of the heater based on the current consumption of the heater and the time after the start of the heater energization. When the initial fuel injection start timing is reached, an initial fuel injection amount is set based on an engine temperature and an initial fuel injection amount of fuel is injected from the fuel injection valve; Heater consumption current change amount detecting means for detecting a change amount of heater consumption current due to injection,
Fuel property detection means for detecting fuel properties based on the amount of change in heater current consumption and the initial fuel injection amount, heater warm-up completion determination means for determining whether warm-up of the heater is completed, and warm-up of the heater. After the completion of the machine, the engine is provided with engine start permission means for permitting engine start, and fuel injection amount setting means for correcting and setting the fuel injection amount after engine start permission based on the fuel property.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the invention, the amount of change in the heater current consumption is corrected by the fuel temperature.

That is, according to the first aspect of the invention, the start of the engine is prohibited, the heater is energized, and after the heater has been warmed up, the initial fuel injection amount is set based on the engine temperature and the initial fuel injection amount Fuel is injected from the fuel injection valve, the amount of change in heater consumption current due to this initial fuel injection is detected, the fuel property is detected based on the amount of change in heater consumption current and the initial fuel injection amount, and after completion of detection of fuel property , Allow the engine to start.

According to the second aspect of the present invention, the start of the engine is prohibited, the heater is energized, and the start timing of the first fuel injection is set before the completion of the warm-up of the heater based on the heater current consumption and the time after the heater energization is started. Then, when the initial fuel injection start timing is reached, the initial fuel injection amount is set based on the engine temperature, the fuel of the initial fuel injection amount is injected from the fuel injection valve, and the change of the heater current consumption by the initial fuel injection is changed. The fuel property is detected based on the amount and the initial fuel injection amount, and after the heater has been warmed up, the engine start is permitted.

According to the third aspect of the present invention, the start of the engine is prohibited, the heater is energized, and after the heater has been warmed up, the initial fuel injection amount is set based on the engine temperature and the fuel of the initial fuel injection amount is set. It is injected from the fuel injection valve, the amount of change in the heater current consumption due to this initial fuel injection is detected, the fuel property is detected based on the amount of change in the heater current consumption and the initial fuel injection amount, and after detection of the fuel property is completed, The engine start is permitted, and the fuel injection amount after the engine start is permitted is corrected based on the detected fuel property.

According to the fourth aspect of the present invention, the start of the engine is prohibited, the heater is energized, and the start timing of the first fuel injection is set before the completion of warming up the heater based on the heater current consumption and the time after the heater energization is started. Then, when the initial fuel injection start timing is reached, the initial fuel injection amount is set based on the engine temperature, the fuel of the initial fuel injection amount is injected from the fuel injection valve, and the change of the heater current consumption by the initial fuel injection is changed. The fuel property is detected based on the amount and the initial fuel injection amount, the engine is allowed to start after the heater has been warmed up, and the fuel injection amount after the engine start is permitted is corrected based on the detected fuel property.

According to a fifth aspect of the invention, in any one of the first to fourth aspects of the invention, the change amount of the heater consumption current is corrected by the fuel temperature, and the heater consumption current corrected by the fuel temperature is corrected. The fuel property is detected on the basis of the change amount and the initial fuel injection amount.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 5 to 15 show a first embodiment of the present invention.

In FIG. 13, reference numeral 1 denotes an engine, and in the figure, a cylinder block 1a is divided into two banks (a left bank on the right side and a right bank on the left side) on both sides of a crank shaft 1b as a center. , In the right bank #
1 shows a horizontally opposed four-cycle four-cylinder gasoline engine in which # 1 and # 3 cylinders are arranged and # 2 and # 4 cylinders are arranged in the left bank. Cylinder heads 2 are provided on both left and right banks of a cylinder block 1a of the engine 1, and an intake port 2a and an exhaust port 2b are formed on each cylinder head 2.

An intake manifold 3 is connected to the intake port 2a, and a throttle valve passage 5 is connected to an upstream collecting portion of the intake manifold 3 via an air chamber 4. An air cleaner 7 is attached to the upstream side of the throttle valve passage 5 via an intake pipe 6, and the air cleaner 7 is connected to an air intake chamber 8. Further, an exhaust pipe 10 is connected to the exhaust port 2b via an exhaust manifold 9, and a catalyst 11 is mounted on the exhaust pipe 10 to be connected to a muffler 12.

Further, the throttle valve passage 5 is provided with a throttle valve 5a interlocked with an accelerator pedal, and an intercooler 13 is interposed in the intake pipe 6 immediately upstream of the throttle valve passage 5, and A resonator chamber 14 is provided downstream of the air cleaner 7 in the intake pipe 6.

The resonator chamber 14 and the intake manifold 3 are communicated with each other by a bypass passage 15 that bypasses the upstream side and the downstream side of the throttle valve 5a. The bypass passage 15 adjusts the amount of idle air. An idle speed control valve (idle speed control valve; ISCV) 16 is installed. Further, a check valve (check valve) that opens immediately downstream of the ISCV 16 when the intake pressure is a negative pressure and closes when the intake pressure becomes a positive pressure by being supercharged by the turbocharger 18. ) 17 is interposed.

In the turbocharger 18, the compressor 18a of the turbocharger 18 has the resonator chamber 14 of the intake pipe 6.
Is installed on the downstream side of the exhaust pipe 10
Is installed in the. Further, a wastegate valve 19 is provided at the turbine housing inlet of the turbocharger 18, and a wastegate valve actuating actuator 20 is connected to the wastegate valve 19.

The wastegate valve actuating actuator 20 is partitioned into two chambers by a diaphragm, one of which forms a pressure chamber 20a communicating with the wastegate valve control duty solenoid valve 21, and the other of which closes the wastegate valve 19. A spring chamber 20b for accommodating a spring urging in the direction is formed, and the opening degree of the waste gate valve 19 is changed according to the control pressure supplied to the pressure chamber 20a. The exhaust gas bypass amount is adjusted to adjust the boost pressure.

The waste gate valve control duty solenoid valve 21 has a port for opening and closing a passage communicating with the resonator chamber 14 with a valve body, and a port communicating with the pressure chamber of the waste gate valve actuating actuator 20. Intake pipe 6 downstream of the turbocharger 18
Is a solenoid three-way duty solenoid valve having a port communicating with the valve of the port communicating with the resonator chamber 14 according to a duty ratio of a control signal output from an electronic control unit 50 (see FIG. 15) described later. The opening is adjusted.

In the present embodiment, as the duty ratio of the control signal output to the wastegate valve control duty solenoid valve 21 increases, the valve opening degree of the port with respect to the resonator chamber 14 increases and leakage occurs. The amount increases, the control pressure supplied to the pressure chamber 20a of the waste gate valve operating actuator 20 decreases, the opening degree of the waste gate valve 19 decreases, and the supercharging pressure increases. Also, the smaller the duty ratio of the control signal, the smaller the valve opening of the port of the wastegate valve control duty solenoid valve 21 communicating with the resonator chamber 14, and the smaller the wastegate valve operating actuator 2 becomes.
A high control pressure is supplied to the zero pressure chamber 20a, the opening degree of the waste gate valve 19 increases, and the supercharging pressure decreases.

On the other hand, an injector 22 as a fuel injection valve is exposed immediately upstream of each intake port 2a of each cylinder of the intake manifold 3, and the cylinder head 2 has a spark plug 23 whose tip is exposed to a combustion chamber. Is installed for each cylinder. An igniter 25 is connected to the ignition coil 24 connected to the ignition plug 23.

The injector 22 has a fuel supply passage 26.
The fuel tank 27 is communicated with the fuel tank 27 through the fuel tank 27, and an in-tank type fuel pump 28 is provided in the fuel tank 27. The fuel from the fuel pump 28 is pressure-fed to the injector 22 and the pressure regulator 30 via the fuel filter 29 provided in the fuel supply passage 26, and is returned from the pressure regulator 30 to the fuel tank 27 to be injected by the injector. The fuel pressure for 22 is adjusted to a predetermined pressure.

A heater unit 31 is provided as an example of a heater for promoting vaporization and atomization of fuel in the fuel injection direction of each injector 22. In the heater unit 31, as shown in FIG. 14, a heating portion 31a is supported in the intake passage by a mounting portion 31c via a stay 31b, and the mounting portion 31c is provided between the intake manifold 3 and the cylinder head 2. It is sandwiched and fixed to the cylinder head 2 by a bolt or the like (not shown).
The heating unit 31a has a PTC pill (Positive temperature Coeffici) on the fuel injection direction side from the injector 22.
ent Pill) built-in PTC heater 31d is built-in. When the PTC heater 31d is energized via the terminal 31e, the fuel f injected from the injector 22 is heated in the heating portion 31a and vaporized, so that the intake air Valve 2c
Is supplied to the combustion chamber via.

Next, the arrangement of the sensors will be described.
Reference numeral 32 is an absolute pressure sensor, and the intake pipe pressure / atmospheric pressure switching solenoid valve 33 selectively detects the intake pipe pressure (intake pressure in the intake manifold 3) and the atmospheric pressure.
Further, directly downstream of the air cleaner 7 of the intake pipe 6,
A thermal intake air amount sensor 34 using a hot wire or a hot film is provided, and a throttle opening sensor for detecting a throttle opening is provided on a throttle shaft of a throttle valve 5a provided in the throttle valve passage 5. Three
A throttle sensor 35 having a built-in 5a and an idle switch 35b that is turned on when the throttle valve 5a is fully closed is provided in series.

The cylinder block 1a of the engine 1
A knock sensor 36 is attached to the cooling water passage 3 that connects the left and right banks of the cylinder block 1a.
A water temperature sensor 38 is exposed at 7, and an O2 sensor 39 is exposed at the collecting portion of the exhaust manifold 9.

A crank rotor 40 is attached to the crank shaft 1b, and a crank angle sensor 41 including an electromagnetic pickup for detecting a protrusion corresponding to a predetermined crank angle is provided on the outer periphery of the crank rotor 40. ing. Further, a cam rotor 43 is connected to the cam shaft 42 of the cylinder head 2, and the cam rotor 43 is connected to the cam rotor 43.
Similarly, a cam angle sensor 44 for discriminating a cylinder, which is also composed of an electromagnetic pickup or the like, is provided oppositely.

On the other hand, in FIG. 15, reference numeral 50 is an electronic control unit (ECU) 50 for controlling the engine 1. The ECU 50 includes a CPU 51, a ROM 52, and an RA.
M53, backup RAM 54, counter / timer group 55, and I / O interface 56 are bus lines 5
A microcomputer which is mainly composed of microcomputers connected to each other via a constant voltage circuit 58 for supplying a stabilizing voltage to each part, and a drive for driving actuators by signals from the output port of the I / O interface 56. The circuit 59 and peripheral circuits such as an A / D converter 60 for converting an analog signal from the sensors into a digital signal are incorporated.

The counter / timer group 55 is used for various counters such as a free-run counter, a counter for counting input of cam angle sensor signals, a fuel injection timer, an ignition timer, and a periodic interrupt for generating a periodic interrupt. For convenience, various timers such as a timer, a timer for measuring an input interval of a crank angle sensor signal, and a watchdog timer for monitoring a system abnormality are collectively referred to, and various software counters and timers are used.

The constant voltage circuit 58 is connected to the battery 62 directly and via the relay contact of the power relay 61, and the relay coil of the power relay 61 is connected to the battery 62 via the ignition switch 63. Has been done.

The fuel pump 28 and the PTC heater 31d are connected to the battery 62 via relay contacts of a fuel pump relay 64 and a heater relay 65, respectively, and the relay coils of the relays 64 and 65 are connected to the battery 62. Is connected to the battery 62, and the other end of the relay coil is connected to the drive circuit 59. A current sensor 45 for detecting the current consumption of the heater is provided in the power supply line between the heater relay 65 and the PTC heater 31d.
Is interposed.

Further, the starter motor relay 66 is connected to the battery 62 via a relay contact of the starter motor relay 66.
7 is connected to the starter motor relay 66.
Has one end of its relay coil connected to the battery 62 via a starter switch 68, and the other end of the relay coil connected to the drive circuit 59.

The input port of the I / O interface 56 is connected with the idle switch 35b, the knock sensor 36, the crank angle sensor 41, the cam angle sensor 44, and the starter switch 68, and the absolute pressure sensor 32 and the suction port. An air amount sensor 34, a throttle opening sensor 35a, a water temperature sensor 38, an O2 sensor 39, and a current sensor 45 are connected via the A / D converter 60, and the A / D converter 60 receives the battery voltage VB. Input and monitored.

On the other hand, the igniter 25 is connected to the output port of the I / O interface 56, and
Via the drive circuit 59, the ISCV 16, the wastegate valve control duty solenoid valve 21, the injector 22, the intake pipe pressure / atmospheric pressure switching solenoid valve 33, and the heater unit 31 provided on the instrument panel (not shown). The heater check lamp 70 for displaying the operating state and the relay coils of the relays 64, 65, 66 are connected.

The ROM 52 stores an engine control program and fixed data such as maps, and the RAM 63 stores data after processing output signals of the sensors and switches, and CPU51
The data processed by is stored. Further, various learning maps and the like are stored in the backup RAM 54, and backup power is constantly supplied from the constant voltage circuit 58 regardless of whether the ignition switch 63 is ON or OFF, and even when the ignition switch 63 is OFF. The data is retained.

The CPU 51 processes the detection signals from the sensors and switches input via the I / O interface 56, the battery voltage VB, etc. according to the control program stored in the ROM 52, and RA
Based on various data stored in the M53 and the backup RAM 54, fixed data stored in the ROM 52, and the like, a fuel injection amount, an ignition timing, a duty signal control signal for the waste gate valve control duty solenoid valve 31,
Various control amounts such as the duty ratio and duty ratio of the drive signal to the ISCV16 are calculated, and each actuator is driven to perform various controls such as air-fuel ratio learning control, ignition timing control, boost pressure control, idle speed control, etc. I do.

At this time, the microcomputer centered on the CPU 51 inhibits the operation of the starter motor 67 to inhibit the start of the engine and starts energizing the PTC heater 31d before executing the various controls. After the PTC heater 31d is warmed up, the injector 2 supplies the fuel of the initial fuel injection amount set by the engine temperature (fuel temperature).
The fuel property is determined based on the amount of change in the heater current consumption after the fuel injection and the initial injection amount, that is, the heavy ratio E of the heavy component of gasoline is obtained, and then the engine start is permitted. The subsequent fuel injection amount is corrected according to the heavy weight ratio E to obtain an appropriate fuel injection amount according to the heavy weight ratio of the fuel, and the starting prohibition means, the heater control means, the heater warm-up according to the present invention are provided. Machine completion determination means, initial fuel injection amount setting means, heater current consumption change amount detection means,
The functions of the fuel property detection means, the engine start permission means, and the fuel injection amount setting means are realized.

The processing performed by the ECU 50 will be described below with reference to the flow charts shown in FIGS.

When the ignition switch 63 is turned on and the ECU 50 is powered on, first, the initialization routine shown in FIG. 5 is executed only for the first time, and step S
1, each data value except the data stored in the backup RAM 54 (flag value, count value, and I /
O port output value) is cleared to initialize the system, and the routine ends.

After the completion of the initialization routine, the routines shown in FIG. 6 and thereafter are executed at predetermined intervals or under predetermined interrupt conditions.

By the end of the system initialization, FIG.
The heater control routine shown in FIG. 7 is executed every predetermined time. First, in step S10, the value of the fuel property detection completion flag F2 is referred to. If the fuel property of F2 = 0 is not detected yet, step S11 is performed. Then, the process proceeds to step S23 and refers to the value of the heater warm-up completion flag F1 to determine whether or not the heater warm-up by the PTC heater 31d is completed.

The heater warm-up completion flag F1 is set when the heater warm-up is completed. When F1 = 0, the heater warm-up is not completed, so the routine proceeds to step S12.
Set the starter motor energization prohibition flag FST (FST ←
1), the start of the engine is prohibited by prohibiting energization to the starter motor 67, and in step S13, the I / O port output value G1 for the fuel pump relay 64 is set (G1 ← 1), and the fuel pump The relay 64 is turned on to drive the fuel pump 28.

Then, in step S14, the heater relay 6
Set the I / O port output value G2 for 5 (G2 ←
1), turn on the heater relay 65 to turn on the PTC heater 31d
Is energized, and in the subsequent step S15, the I / O port output value G3 for the heater check lamp 70 is set (G
3 ← 1), heater check lamp 7 showing that the heater is energized
Turn on 0.

Then, the process proceeds to step S16, the count value C1 is compared with the set value T1, it is judged whether the set time determined by the set value T1 has been reached after the start of energization of the heater, and C
When 1 <T1, in step S17, the count value C1 is incremented and the routine is exited.

The count value C1 is used to measure the time after the start of energization of the heater as a condition for determining the completion of warming up the heater, and is cleared after the completion of warming up the heater.
After the heater is warmed up, it is used to measure the time after the start of the first fuel injection as a condition for detecting the amount of change in the heater current consumption for determining the fuel property.

Further, when C1 ≧ T1 and the time after the start of energizing the heater reaches the set time, the routine proceeds to step S18, where the heater current consumption I detected by the current sensor 45.
Is compared with the heater warmup completion determination value Is to determine whether the temperature of the PTC heater 31d has risen sufficiently and the heater warmup has been completed.

Here, as shown in FIG. 12, when the PTC heater 31d is energized, the heater current consumption I rises, and when the temperature rises to reach the Curie point, the resistance value rises sharply. The consumption current I starts to decrease, and thereafter, the temperature of the PTC heater 31d becomes substantially saturated and the consumption current becomes a substantially constant value. Therefore, it is not possible to judge the heater warm-up completion only by the heater consumption current I. Therefore, the heater current consumption I is compared with the heater warm-up completion determination value Is after the heater current consumption I starts to decrease after the lapse of the set time determined by the set value T1 avoiding the initial start of heater energization. When I falls below the heater warm-up completion determination value Is, it is determined that the heater warm-up is completed, so that the erroneous determination of the heater warm-up completion is prevented.

Then, in step S18, I> Is
If the heater warm-up is not completed, the routine is exited, and if the heater warm-up is completed for I ≦ Is, step S1 is performed.
9, the count value C1 is cleared, and step S
At 20, the heater warm-up completion flag F1 indicating that the heater warm-up is completed is set (F1 ← 1), and step S2 is performed.
In the processing of 1 or less, the fuel property based on the amount of change in the heater current consumption I, that is, the heavy weight ratio E due to the heavy weight component of gasoline
In order to obtain the above, the fuel of the first fuel injection amount is injected only once from the injectors 22 of all the cylinders simultaneously.

In step S21, the table stored as fixed data in a series of addresses in the ROM 52 is referred to based on the cooling water temperature Tw by the water temperature sensor 38,
The initial fuel injection pulse width Tis that determines the initial fuel injection amount is set. That is, since the fuel evaporation rate is low when the engine temperature is low, it is necessary to relatively increase and correct the fuel supply amount to the engine as the engine temperature is lower. Then, the fuel is injected from the injector 22 only once before the engine is started, and the evaporated fuel is immediately supplied to the combustion chamber of the engine 1 by the heating of the fuel by the heater unit 31, so that the startability is improved.

Therefore, as shown in step S21,
In the above table, the optimum initial fuel injection pulse width Tis, which is obtained in advance by experiments or the like, is stored with a larger value as the cooling water temperature Tw is lower and the engine temperature is lower.

Then, in step S22, the heater current consumption I is read and stored in the RAM 53 at a predetermined address as the heater current consumption value I0 immediately before the first fuel injection. In step S23, the initial fuel injection pulse set in step S21 is set. The injection pulse signal of width Tis is output to the injector 22 of each cylinder, and the routine ends.

As a result, before the engine is started, the fuel of the amount corresponding to the initial fuel injection pulse width Tis is injected from the injector 22 of each cylinder at the same time for all the cylinders.

Since the heater warm-up completion flag F1 is set by the completion of the heater warm-up, the routine proceeds from step S11 to step S24 when the routine is executed next time and thereafter. In step S24, the count value C1 and the set value T
2 is compared, and the time after the start of the first fuel injection is set value T
It is determined whether the set time determined by 2 has been reached.

When the fuel having the first fuel injection pulse width Tis is injected from the injector 22 after the heater has been warmed up, as shown in FIG. 12, it is built in the heating unit 31a of the heater unit 31 by the injected fuel. The PTC heater 31d is cooled, and the heater current consumption I increases again. Here, under a unique fuel injection amount, the fuel injected from the injector 22, that is, the fuel having a low gasoline heaviness and a high volatility has a large evaporation amount per unit time, and therefore the latent heat of vaporization is large. By PTC heater 3
The temperature decrease of 1d becomes large, and the heater current consumption I greatly increases as shown by the solid line in the figure. On the other hand, in the case of gasoline with a high proportion of heavy substances and poor volatility, on the contrary, the amount of evaporation per unit time is small and the temperature drop of the PTC heater 31d is relatively small, and the heater current consumption I is as shown by the broken line in the figure. The rise will be small.

Therefore, it is possible to determine the fuel property, that is, the proportion of heavier gasoline by the change amount ΔI of the heater current consumption I due to the first fuel injection. However, as described above, since the initial fuel injection pulse width Tis of the initial fuel injection amount is variably set according to the engine temperature (water temperature Tw), the fuel property cannot be determined only by the change amount ΔI of the heater current consumption. Therefore, as will be described in detail later, the fuel property is determined using the initial fuel injection pulse width Tis and the heater consumption current variation ΔI as parameters.

Further, as shown in FIG. 12, the set value T2 is set after the heater current consumption I increases by the initial fuel injection.
Further, thereafter, the time for obtaining the maximum value I1 of the heater consumption current I used when calculating the variation amount ΔI of the heater consumption current until the heater consumption current I decreases is set.

Then, in step S24, C1≤T
When it is 2, the process proceeds to step S25, the heater current consumption I is compared with the heater current consumption maximum value I1 after the initial fuel injection stored in a predetermined address of the RAM 53, and when I1 ≧ I, the process directly returns to step S17 and counts. The value C1 is incremented, the routine is exited, and I1 <I
If so, the maximum value I1 is updated by the heater current consumption I in step S26, and the routine exits via step S17.

When the time after the start of the initial fuel injection reaches the set time determined by the set value T2, CI ≧ T2, and the routine proceeds from step S24 to step S27, and the maximum value I1 and the heater consumption immediately before the initial fuel injection are reached. Current value I0
And are read out to calculate the change amount ΔI of the heater current consumption (ΔI ← I1-I0).

Then, in step S28, the change amount ΔI of the heater current consumption and the initial fuel injection pulse width Tis.
A parameter is used as a parameter to search the table, and the heavy fuel ratio E of gasoline as a fuel property is calculated by interpolation calculation.

FIG. 8 shows an example of a table for determining the gasoline heavy weight ratio E (%) as the fuel property based on the change amount ΔI of the heater current consumption and the initial fuel injection pulse width Tis. As described above, the lower the proportion of gasoline is heavy and the higher the volatility of the fuel, the greater the amount of evaporation per unit time. Therefore, the temperature drop of the PTC heater 31d is increased by the latent heat of vaporization, and the amount of change in the heater current consumption is increased. On the other hand, in the case of gasoline with a large ΔI and a high proportion of heavy substances and poor volatility, on the contrary, the evaporation amount per unit time is small and the PTC heater 3
The temperature drop of 1d is relatively small, and the change amount ΔI of the heater current consumption is small.

The initial fuel injection amount is set so that the initial fuel injection pulse width Tis is variably set according to the engine temperature (water temperature Tw). As the initial fuel injection pulse width Tis is larger and the initial fuel injection amount is larger, the heater current consumption is relatively increased. The change amount ΔI of Δ decreases.

Therefore, the gasoline heavy fraction E corresponding to the heater consumption current change amount ΔI and the initial fuel injection pulse width Tis as parameters is previously obtained by an experiment or the like, and RO
It is stored as a table in a series of addresses of M52, and the heavy weight ratio E of gasoline is judged by referring to the table.

From these, the initial fuel injection pulse width Ti
Since s is variably set to an optimum value according to the engine temperature, the startability can be improved and the initial fuel injection pulse width T
is and the amount of change in heater current consumption due to initial fuel injection ΔI
By determining the fuel property based on the above, it is possible to accurately determine the fuel property, and it is possible to improve both the startability and the fuel property detection reliability.

Further, by correcting the subsequent fuel injection amount in accordance with the heavy weight ratio of gasoline as the fuel property, it is possible to always supply an appropriate fuel amount to the engine, and the combustibility is maintained regardless of the fuel property. Is improved and exhaust emission is improved.

Next, in step S29, the fuel property detection completion flag F2 is set upon completion of the fuel property detection (F2 ← 1), and in step S30, the starter motor energization prohibition flag FST is cleared (FST ← 0). , The start of the engine is permitted by permitting the energization of the starter motor 67, and in the subsequent step S31, the count value C1 is cleared and the routine exits.

When the fuel property detection completion flag F2 is set by the completion of the detection of the fuel property, in the next and subsequent routines, the routine branches from step S10 to step S32, and the cooling water temperature Tw is preset in step S32. Fuel vaporizable temperature TLA4 (at the cooling water temperature corresponding to the wall temperature of the intake port 2a where the fuel adhering to the wall can be vaporized,
For example, if Tw <TLA4, the process proceeds to step S33, the I / O port output value G2 for the heater relay 65 is set (G2 ← 1), and the heater relay 65 is turned on to turn on the PTC heater. Energize 31d,
The heater unit 31 promotes the vaporization of the fuel injected from the injector 22, and in the subsequent step S34, the I / O port output value G3 for the heater check lamp 70 is increased.
Is set (G3 ← 1), the heater check lamp 70 indicating that the heater is energized is turned on, and the routine is exited.

When Tw ≧ TLA4, heating of the injected fuel by the heater unit 31 is unnecessary,
In step S35, I for the heater relay 65
/ O port output value G2 is cleared (G2 ← 0), the heater relay 65 is turned off to de-energize the PTC heater 31d, and the heating of the fuel injected from the injector 22 by the heater unit 31 is stopped, and in step S36,
The I / O port output value G3 for the heater check lamp 70 is cleared (G3 ← 0), and the heater check lamp 7
Turn off 0 and exit the routine.

Therefore, after the fuel property is detected, the heater unit 31 promotes vaporization and atomization of the injected fuel only when necessary.

The starter motor energization prohibition flag FST set or cleared by the above heater control routine is
Referring to the starter motor control routine shown in FIG. 8, the operation of the starter motor 67 is prohibited or permitted according to the value of the starter motor energization prohibition flag FST.

This starter motor control routine is executed at predetermined time intervals only when the starter switch 68 is ON after the completion of the above initialization routine. First, at step S40, the starter motor energization prohibition flag FST is set. If the energization of the starter motor 67 of FST = 0 is permitted and the engine start is permitted, the process proceeds to step S41, and the I / O port output value G4 for the starter motor relay 66 is set (G4 ← 1), the starter motor relay 66 is turned on to start the engine by operating the starter motor 67.

On the other hand, when the energization of the starter motor 67 of FST = 1 is prohibited and the engine start is prohibited in step S40, the process proceeds to step S42, and the I / O port output value G for the starter motor relay 66 is set.
4 is cleared (G4 ← 0), starter motor relay 66
Is turned off to prohibit the operation of the starter motor 67, prohibit the engine from starting, and exit the routine.

Therefore, the starter switch 68 is turned on until the detection of the fuel property is completed after the heater has been warmed up.
Regardless of this, the start of the engine is prohibited by prohibiting the operation of the starter motor 67. It should be noted that during this period, since it is a very short time (several seconds), the engine can be started without feeling awkward.

Further, the flow chart shown in FIG. 9 is a starter switch ON → OFF interrupt routine which is activated by interruption when the starter switch 68 is turned OFF.
In step S50, the output value G4 of the I / O port for the starter motor relay 66 is cleared (G4 ← 0), the starter motor relay 66 is turned off, and the starter motor 67 is turned off.
Stop the operation of and exit the routine.

Further, the gasoline heavy ratio E as the fuel property detected in the above heater control routine is referred to in the fuel injection amount setting routine shown in FIG.
The fuel injection amount is corrected according to the gasoline heavy weight ratio E, and an appropriate fuel injection amount corresponding to the gasoline heavy weight ratio is set. This fuel injection amount setting routine is executed every predetermined period after the engine start is permitted, and the fuel injection pulse width Ti as the fuel injection amount is set for each fuel injection target cylinder.

In this fuel injection amount setting routine,
In step S61, the basic fuel injection that determines the basic fuel injection amount from the engine speed N calculated based on the output signal from the crank angle sensor 41 and the intake air amount Q based on the output signal from the intake air amount sensor 34. Pulse width Tp
Is calculated (Tp ← K × Q / N; K ... Injector correction constant), and in step S62, the water temperature increase coefficient KTW is set by referring to the table based on the cooling water temperature Tw.

The water temperature increase coefficient KTW is used for correcting the fuel amount increase for ensuring the drivability in the cold engine condition. As shown in step S62, the fuel amount increase increases as the cooling water temperature TW decreases. The water temperature increasing coefficient KTW having a large value is set as much as possible.

Next, at step S63, the post-idle increase coefficient KAI is set. This post-idle increase coefficient KAI is for preventing the rattling at the time of releasing the idle, and when the idle valve 35b is switched from fully closed to open and the idle switch 35b is switched from ON to OFF, the initial value is based on the cooling water temperature TW. It is set, and thereafter, the set value is gradually decreased every time the routine is executed until it becomes 0.

In the following step S64, the acceleration increasing coefficient KACC for correcting the fuel increase at the time of acceleration is set based on the throttle opening change amount ΔTh by the throttle opening sensor 35a and the cooling water temperature TW. A fuel property correction coefficient KJGA for reading out the gasoline heavy ratio E as the fuel property detected in the heater control routine and correcting the fuel injection amount according to the heavy ratio E
Is set by table reference.

That is, as the gasoline heavy ratio E is high and the amount of heavy components in the gasoline is large, the fuel is less likely to be vaporized, and the air-fuel ratio tends to become rich under the same fuel amount. As shown in the figure, the higher the gasoline heavy fraction E, the larger the fuel property correction coefficient KJGA is set to increase the fuel amount.

Then, in step S66, the water temperature increasing coefficient KTW, the post-idle increasing coefficient KAI, and the acceleration increasing coefficient KAC.
C, and the fuel property correction factor KJGA, various increase factors C
Calculate OEF (COEF ← 1 + KTW + KAI + KACC +
KJGA), in step S67, the air-fuel ratio feedback correction coefficient α stored in the predetermined address of the RAM 53.
Is read.

Next, in step S68, the intake air amount measuring system such as the intake air amount sensor and the fuel supply system such as the injector are produced based on the engine speed N and the basic fuel injection pulse width Tp representing the engine load. The learning value KLR is searched by referring to the air-fuel ratio learning map of the backup RAM 54, which stores the results of learning the air-fuel ratio deviation due to time variations and changes over time, and the learning correction coefficient KBL is calculated by interpolation calculation.
Set RC.

In the following step S69, the battery voltage V
Based on B, a voltage correction coefficient Ts for interpolating the invalid injection time of the injector 22 is set.

Then, in step S70, the basic fuel injection pulse width Tp calculated in step S61 is multiplied by the various increase correction coefficients COEF calculated in step S66 and the air-fuel ratio feedback correction coefficient α read in step S67. The air-fuel ratio is corrected, and the learning correction is performed by multiplying the air-fuel ratio learning correction coefficient KBLRC set in step S68. Further, the voltage correction coefficient Ts set in step S69 is added to correct the voltage, and the final correction is made. The fuel injection pulse width Ti that determines the fuel injection amount is set (Ti
← Tp × COEF × α × KBLRC + Ts).

Then, in step S71, the fuel injection pulse width Ti is set in the injection timer for the corresponding cylinder, and the routine exits.

As a result, when the predetermined timing is reached, the injection timer is started and the injector 2 of the corresponding cylinder is started.
A drive pulse signal having a fuel injection pulse width Ti is output to 2 and a quantity of fuel corresponding to the fuel injection pulse width Ti is injected.

Therefore, the fuel property correction coefficient KJGA is set according to the gasoline heavy ratio E as the fuel property, and the fuel injection amount is corrected by this fuel property coefficient KJGA.
It becomes possible to always supply an appropriate amount of fuel to the engine according to the fuel property, the combustibility is improved regardless of the fuel property, and the exhaust emission is improved.

Next, a second embodiment of the present invention will be described.

In contrast to the first embodiment described above, the present embodiment detects the gasoline heavy weight ratio E as a fuel property before the heater warm-up is completed, and the microcomputer centering on the CPU 51 controls various controls. Prior to the execution of, the starter motor 67 is prohibited from operating to inhibit the engine from starting, the PTC heater 31d is energized, and the start timing of the first fuel injection is set based on the heater current consumption and the time after the heater energization is started. It is set before the heater is warmed up, and when the initial fuel injection start timing is reached, the injector 22 injects the fuel of the initial fuel injection amount set by the engine temperature (fuel temperature), and the heater after this fuel injection is performed. Based on the amount of change in the consumed current and the initial injection amount, the fuel property, that is, the heavy weight ratio E of the heavy gasoline component is detected, and after warming up the heater, The starting of the gin is permitted, and the subsequent fuel injection amount is corrected according to the detected gasoline fuel weight ratio E as a fuel property to obtain an appropriate fuel injection amount according to the fuel weight level. Of the functional means in the first embodiment, the functions of the initial fuel injection amount setting means and the engine start permitting means are slightly different, and the functions of the initial fuel injection start timing setting means are realized. . That is, specifically, a part of the heater control routine is changed from the first embodiment.

The heater control routine according to this embodiment is shown in FIGS. The same steps as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, first, step S10.
1, the value of the heater warm-up completion flag F1 is referred to, and F1 =
When the heater warm-up of 0 is not completed, step S
In step 102, the value of the fuel property detection completion flag F2 is referred to. Then, when the fuel property of F2 = 0 is not detected yet, the process proceeds to step S103, and it is determined whether the initial fuel injection is completed by referring to the value of the initial fuel injection completion flag F3.

The initial fuel injection completion flag F3 is set when the initial fuel injection for detecting the fuel property is completed. When F3 = 0, the initial fuel injection is not completed, so the routine proceeds to step S12, Step S12-
In step S16 after S15, the count value C1 is compared with the set value T1 to determine whether the set time determined by the set value T1 has been reached after the heater energization is started. If C1 <T1, in step S17, The count value C1 is counted up and the routine exits.

Here, as shown in FIG. 17, the count value C1 is used as a condition for determining whether the heater current consumption I that determines the initial fuel injection timing has reached the set value It before the completion of heater warm-up. It is used to measure the time after the start of energization, and is cleared when the heater current consumption reaches the set value It, and then as a condition for detecting the amount of change in the heater current consumption for determining the fuel property, the first time. It is used to measure the time after the start of fuel injection.

When C1 ≧ T1 and the time after the start of heater energization reaches the set time, the routine proceeds to step S104, where the heater current consumption I detected by the current sensor 45 is I.
And a set value It that determines the initial fuel injection timing,
Determine if the first fuel injection timing has been reached.

That is, as shown in FIG. 17, when the PTC heater 31d is energized, the heater current consumption I
When the temperature rises and reaches the Curie point, the resistance value sharply rises and the consumption current I begins to decrease. After that, the temperature of the PTC heater 31d becomes substantially saturated and the consumption current has a substantially constant value. Therefore, in order to judge the fuel property by the change amount ΔI of the heater consumption current before the heater warming up is completed, the PTC heater 31d is energized and the heater consumption current I rises. A set value I capable of detecting the heater consumption current variation ΔI due to injection
It is necessary to inject the initial fuel when the fuel pressure drops to t. Therefore, only the heater current consumption I cannot determine the initial fuel injection timing because the heater current consumption decreases after the heater current consumption rises. Therefore, avoiding the beginning of heater energization, after the set time determined by the set value T1 elapses, the heater current consumption I starts to decrease and then the heater current consumption I
And the set value It are compared, and the heater current consumption I is set to the set value I.
When it is reduced to t or less, it is determined that the initial fuel injection timing has been reached, thereby preventing an erroneous determination of the initial fuel injection timing.
Then, in step S104, when I> It, it is determined that the initial fuel injection timing has not been reached, and the routine exits. When I ≦ Is, the initial fuel injection timing is reached, and the routine proceeds to step S19, where the count value C1 is reached. In step S21, the initial fuel injection pulse width Tis that determines the initial fuel injection amount is set by referring to the table based on the cooling water temperature Tw in step S21.
In step 22, the heater current consumption I is read and stored in a predetermined address of the RAM 53 as the heater current consumption value I0 immediately before the first fuel injection. In step S23, the injection pulse signal having the initial fuel injection pulse width Tis set in step S21 is set. The fuel is output to the injector 22 of each cylinder, and in step S105, the initial fuel injection completion flag F3 indicating the completion of the initial fuel injection is set (F3 ← 1), and the routine exits.

As a result, before the heater is completely warmed up, the injector 22 of each cylinder simultaneously injects a quantity of fuel corresponding to the initial fuel injection pulse width Tis.

Since the initial fuel injection completion flag F3 is set by the completion of the initial fuel injection, the routine proceeds from step S103 to step S24 in the above-described first embodiment (see FIG. 7) when the routine is executed from the next time onward. By the processing of steps S24 to S31, the change amount ΔI of the heater current consumption is calculated in the same manner as in the first embodiment, and the heater current consumption and the initial fuel injection pulse width Tis are used as parameters to refer to the table as a gasoline fuel property. The heavy weight ratio E of the is detected.

In this embodiment, since the fuel property is detected before the heater is warmed up, the process of clearing the starter motor energization prohibition flag FST in step S30 is omitted.

When the fuel property detection completion flag F2 is set by the completion of the fuel property detection, in the routine after the next step, steps S102 to S106.
In step S106, the heater current consumption I and the heater warm-up completion determination value Is are compared to determine whether the heater warm-up is completed. If the heater warm-up of I> Is is not completed, When the heater warm-up is completed for I≤Is, the routine proceeds to step S107, where the starter motor energization prohibition flag FST is cleared to permit energization of the starter motor 67 to permit engine start, and in step S108. The heater warm-up completion flag F1 indicating that the heater warm-up is completed is set (F1 ← 1) and the routine is exited.

Then, by setting the heater warm-up completion flag F1, step S101 is performed in the next and subsequent routines.
The process branches from step S32 to step S32, and by the processing of steps S32 to S36, as in the first embodiment, the heater unit 31 adjusts the injected fuel only when necessary according to the comparison result of the cooling water temperature Tw and the fuel vaporizable temperature TLA4. Vaporization and atomization are promoted.

Then, for the starter motor control, the same processing as in FIGS. 8 and 9 described above is performed, and the gasoline heavy ratio E as the fuel property detected by the heater control routine is shown in FIG. It is referred to in the fuel injection amount setting routine, and the fuel injection amount is corrected according to the fuel property as in the first embodiment.

According to this embodiment, the fuel property is detected before the completion of the warm-up of the heater, so that it is possible to start the engine relatively earlier than in the first embodiment. Discomfort due to the prohibition of the starter motor operation is further eliminated.

Next, a third embodiment of the present invention will be described.

In the present embodiment, the engine 1 according to the first embodiment described above is an alcohol engine (Flexible Fuel Vehicle engine) that can use not only gasoline but also a mixed fuel of alcohol and gasoline, or only alcohol. As shown by the broken line in FIG. 13, the alcohol concentration sensor 80 is additionally provided in the fuel supply passage 26 of the alcohol engine. Further, as shown by the broken line in FIG.
The output signal from the alcohol concentration sensor 80 is connected to the A / D converter 60 of the I / D converter 60 through the I / D converter 60.
Input to the input port of the O interface 56. Other configurations of the engine and the configuration of the ECU are the same as those of the first embodiment, and thus the description thereof will be omitted.

Further, in the present embodiment, in contrast to the above-described first embodiment, the alcohol concentration sensor 8 is used in the heater control routine.
The initial fuel injection pulse width Tis is set based on the alcohol concentration M and the cooling water temperature Tw detected by 0, and the fuel is based on the initial fuel injection pulse width Tis, the alcohol concentration M, and the change amount ΔI of the heater current consumption. The property is determined, and the fuel injection amount is corrected in the fuel injection amount setting routine based on the fuel property, and the fuel injection amount is corrected based on the alcohol concentration M.

FIG. 18 shows a heater control routine according to this embodiment.
~ Shown in FIG. The same steps as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, steps S10 to S1.
Heater warm-up completion flag F1 in step S20
After setting, the process proceeds to step S201, and the table stored as fixed data in a series of addresses of the ROM 52 is referred to for the first time based on the alcohol concentration M by the accol concentration sensor 80 and the cooling water temperature Tw by the water temperature sensor 38. The initial fuel injection pulse width Tis that determines the fuel injection amount is set.

That is, since the fuel evaporation rate is low when the engine temperature is low, it is necessary to relatively increase and correct the fuel supply amount to the engine as the engine temperature is lower, and as the alcohol concentration M in the fuel is higher, Since the calorific value of is small and the theoretical air-fuel ratio is small, it is necessary to increase the amount of fuel supply to the engine. Therefore, in the above table, the optimum initial fuel injection pulse width Tis, which is obtained in advance by experiments or the like, is stored as the cooling water temperature Tw is low, the engine temperature is low, and the alcohol concentration M is high.

Then, in step S22, the heater current consumption I is read and stored in a predetermined address of the RAM 53 as the heater current consumption value I0 immediately before the first fuel injection. In step S23, the initial fuel injection pulse set in step S201 is set. The injection pulse signal of width Tis is output to the injector 22 of each cylinder, and the routine ends.

As a result, before the engine is started, the injector 22 of each cylinder simultaneously injects a quantity of fuel corresponding to the initial fuel injection pulse width Tis.

When the heater warm-up completion flag F1 is set by the completion of heater warm-up, the count value C1 will be changed from step S11 to step S24 by the processing of step S24 to step S26 when the routine is executed next time and thereafter. Until the set value T2 is reached, the maximum value I1 is updated according to the comparison result with the heater current consumption I, and the time after the start of the first fuel injection reaches the set time determined by the set value T2 and C1 ≧ T2. , Step S2
4 to step S27, the maximum value I1 and the heater current consumption value I0 immediately before the first fuel injection are read to calculate the heater current consumption change amount ΔI, and step S202
Then, the change amount ΔI of the heater current consumption and the step S
A table is searched with the initial fuel injection pulse width Tis by 201 and the alcohol concentration M as parameters, and the fuel heavy ratio E as a fuel property is calculated by interpolation calculation.

Here, when the alcohol concentration M = 0%, that is, the fuel when the gasoline is 100% and the fuel when the alcohol concentration is 100% and the alcohol is 100%, the change amount ΔI of the heater current consumption and the initial fuel injection pulse width Tis. 21 (a) and 21 (b) respectively show an example of a table for determining the fuel heavy ratio E (%) as the fuel property by the above. That is, the higher the alcohol concentration M is, the larger the latent heat of vaporization is, and under the same fuel injection amount, a large amount of heat is taken away by the fuel evaporation, the change amount ΔI of the heater current consumption increases, and the heavy fuel ratio is low. The more highly fuel the fuel has, the larger the amount of evaporation per unit time. Therefore, the latent heat of vaporization causes a large decrease in the temperature of the PTC heater 31d, the amount of change ΔI in the heater current consumption becomes large, and the ratio of heavy fuel is high and the volatility is high. On the contrary, when the fuel is bad, the amount of evaporation per unit time is small and the temperature drop of the PTC heater 31d is relatively small, and the change amount ΔI of the heater current consumption is small.

The initial fuel injection amount is set such that the initial fuel injection pulse width Tis is variably set according to the engine temperature (water temperature Tw) and the alcohol concentration M, and the initial fuel injection pulse width Ti is set.
As s is large and the initial fuel injection amount is large, the change amount ΔI of the heater current consumption decreases relatively.

Therefore, the heavy fuel ratio E corresponding to the heater consumption current change amount ΔI, the initial fuel injection pulse width Tis, and the alcohol concentration M is obtained as a parameter by an experiment or the like in advance, and is stored in a series of addresses of the ROM 52 as a table. The initial fuel injection pulse width Tis is variably set to an optimum value in accordance with the engine temperature and the alcohol concentration M. By improving the fuel property based on the initial fuel injection pulse width Tis, the change amount ΔI of the heater current consumption due to the initial fuel injection, and the alcohol concentration M, it is possible to improve the accuracy even in the present embodiment employing the alcohol engine. It is possible to determine the fuel property at the same time, and it is possible to improve the startability and the reliability of the fuel property detection at the same time. It is possible.

Further, by correcting the subsequent fuel injection amount in accordance with the fuel heavy ratio as the fuel property, it is possible to always supply an appropriate fuel amount to the engine, and to improve the combustibility regardless of the fuel property. Is improved and exhaust emission is improved.

Next, in step S29, the fuel property detection completion flag F2 is set when the fuel property detection is completed (F2 ← 1), and in step S30, the starter motor energization prohibition flag FST is cleared (FST ← 0). , The start of the engine is permitted by permitting the energization of the starter motor 67, and in the subsequent step S31, the count value C1 is cleared and the routine exits.

When the fuel property detection completion flag F2 is set by the completion of the detection of the fuel property, the routine from the next onward branches from step S10 to step S32, and by the processing of step S32 to step S36, the first form is executed. Similarly, the heater unit 31 promotes vaporization and atomization of the injected fuel only when necessary according to the comparison result of the cooling water temperature Tw and the fuel vaporizable temperature TLA4.

Note that the starter motor control is performed in the same manner as in FIGS. 8 and 9 described above. Further, the fuel heavy ratio E as the fuel property detected by the heater control routine is referred to in the fuel injection amount setting routine shown in FIG.

That is, as in the first embodiment, step S
The basic fuel injection pulse width T that determines the basic fuel injection amount at 61
p is calculated, and the water temperature increase coefficient KTW, the post-idle increase coefficient KAI, and the acceleration increase coefficient KACC are set in steps S62, S63, and S64, respectively, and then in step S65, the fuel property detected in step S202 of the heater control routine Is read out, and a fuel property correction coefficient KJGA for correcting the fuel injection amount according to the heavy ratio E is set by referring to a table.

That is, the fuel is less likely to be vaporized as the fuel heavy ratio E is higher and the heavy components in the fuel are larger, and the air-fuel ratio tends to become rich under the same fuel amount. As shown, the higher the fuel weight ratio E is,
A large value of the fuel property correction coefficient KJGA is set to increase the fuel amount.

Then, in step S66, the water temperature increasing coefficient KTW, the post-idle increasing coefficient KAI, and the acceleration increasing coefficient KAC.
C, and the fuel property correction factor KJGA, various increase factors C
Calculate OEF (COEF ← 1 + KTW + KAI + KACC +
KJGA), the process proceeds to step S210, and the alcohol concentration M
Based on the above, the alcohol concentration correction coefficient Ka is set by referring to the table.

That is, the higher the alcohol concentration M in the fuel, the smaller the calorific value of the fuel and the theoretical air-fuel ratio, so it is necessary to increase the fuel amount.
As shown in 210, when the alcohol concentration is 0%, the alcohol concentration correction coefficient Ka is set to 1.0, and a larger alcohol concentration correction coefficient Ka is stored as the alcohol concentration M in the fuel increases. ing.

Next, in step S67, the air-fuel ratio feedback correction coefficient α is read out, and in steps S68, 6
At 9, the learning correction coefficient KBLRC and the voltage correction coefficient Ts are set.

Then, in step S211, the various increase correction coefficients COEF calculated in step S66 are added to the basic fuel injection pulse width Tp calculated in step S61.
The alcohol concentration correction coefficient Ka set in step S210 and the air-fuel ratio feedback correction coefficient α read in step S67 are multiplied to correct the air-fuel ratio, and the air-fuel ratio learning correction coefficient KBLRC set in step S68 is also multiplied. Correction by learning, and further, the above step S6
The voltage correction coefficient Ts set in 9 is added to correct the voltage,
Set the fuel injection pulse width Ti that determines the final fuel injection amount (Ti ← Tp × COEF × Ka × α × KBLRC + T
s).

Then, in step S71, the fuel injection pulse width Ti is set in the injection timer for the corresponding cylinder, and the routine exits.

As a result, when the predetermined timing is reached, the injection timer is started and the injector 2 of the corresponding cylinder is started.
A drive pulse signal having a fuel injection pulse width Ti is output to 2 and a quantity of fuel corresponding to the fuel injection pulse width Ti is injected.

Therefore, the fuel property correction coefficient KJGA is set in accordance with the fuel heavy ratio E as the fuel property, and the alcohol concentration correction coefficient Ka is set in accordance with the alcohol concentration M in the fuel. The fuel injection amount is corrected by the coefficient KJGA and the alcohol concentration correction coefficient Ka, and it becomes possible to always supply an appropriate fuel amount to the engine according to the heavy weight ratio of the fuel and the alcohol concentration in the fuel. In addition, the combustibility is improved and the exhaust emission is improved regardless of the fuel property.

In the present embodiment as well, the above-mentioned second
Similar to the embodiment, the fuel heavy ratio as a fuel property may be detected before the heater warm-up is completed.

Further, in each of the above embodiments, the fuel temperature may be detected and the amount of change in the heater current consumption may be corrected by the fuel temperature. In this case, under the same fuel property, the lower the fuel temperature, the larger the change amount of the heater current consumption. Therefore, the lower the fuel temperature, the smaller the correction amount of the heater current consumption is corrected. This makes it possible to further improve the accuracy of detecting the fuel property.

[0132]

According to the first aspect of the present invention, the starting of the engine is prohibited, the heater is energized, and after the heater is warmed up, the initial fuel injection amount is set based on the engine temperature, and the initial fuel injection is set. Inject a certain amount of fuel from the fuel injection valve, and detect the amount of change in heater current consumption due to this initial fuel injection,
The fuel property is detected based on the amount of change in the heater current consumption and the initial fuel injection amount, and after the completion of the detection of the fuel property, the engine start is permitted. Therefore, the initial fuel injection amount is variably set to the optimum value according to the engine temperature. As a result, the startability can be improved, and the fuel property can be determined accurately based on the initial fuel injection amount and the change amount of the heater current consumption due to the initial fuel injection. Therefore, it is possible to improve the startability and the reliability of the fuel property detection at the same time.

According to the second aspect of the present invention, the start of the engine is prohibited, the heater is energized, and the start timing of the first fuel injection is set based on the heater current consumption and the time after the heater energization is started before the heater is warmed up. When the initial fuel injection start timing is reached, the initial fuel injection amount is set based on the engine temperature and the fuel of the initial fuel injection amount is injected from the fuel injection valve. The fuel property is detected based on the change amount of
After the heater is warmed up, the engine is allowed to start, so
The initial fuel injection amount is variably set to an optimum value according to the engine temperature, whereby the startability can be improved, and the fuel consumption can be improved based on the initial fuel injection amount and the change amount of the heater current consumption due to the initial fuel injection. Since the property is determined, it is possible to accurately determine the fuel property, and it becomes possible to improve both the startability and the reliability of the fuel property detection.
Further, the fuel property is detected before the heater is warmed up, so that the engine start can be started relatively early in comparison with the invention according to the above-mentioned claim 1, and the engine start is prohibited at the engine start. The discomfort caused by is further eliminated.

According to the third aspect of the present invention, the engine start is prohibited, the heater is energized, and after the heater has been warmed up,
The initial fuel injection amount is set based on the engine temperature, the fuel of the initial fuel injection amount is injected from the fuel injection valve, and the change amount of the heater current consumption due to the first fuel injection is detected. The fuel property is detected based on the initial fuel injection amount, the engine start is permitted after the detection of the fuel property is completed, and the fuel injection amount after the engine start permission is corrected based on the detected fuel property. In addition to the effects of the invention described, after the fuel property is detected, an appropriate amount of fuel can always be supplied to the engine according to the fuel property, the combustibility is improved regardless of the fuel property, and the combustion property improves the exhaust gas. Emissions are improved.

According to the fourth aspect of the present invention, the start of the engine is prohibited, the heater is energized, and the start timing of the first fuel injection is set before the completion of the warm-up of the heater based on the heater current consumption and the time after the heater energization is started. Then, when the initial fuel injection start timing is reached, the initial fuel injection amount is set based on the engine temperature, the fuel of the initial fuel injection amount is injected from the fuel injection valve, and the change of the heater current consumption by the initial fuel injection is changed. The fuel property is detected based on the fuel injection amount and the initial fuel injection amount, the engine start is allowed after the heater is warmed up, and the fuel injection amount after the engine start permission is corrected based on the detected fuel property. In addition to the effect of the invention described in Item 2, after the fuel property is detected, an appropriate amount of fuel can always be supplied to the engine according to the fuel property, so that the combustibility is improved regardless of the fuel property, and the combustibility is improved. Has the effect of exhaust emission can be improved by improving.

According to a fifth aspect of the invention, in any one of the first to fourth aspects of the invention, the amount of change in the heater consumption current is corrected by the fuel temperature, and the heater consumption current corrected by the fuel temperature is corrected. Since the fuel property is detected based on the change amount and the initial fuel injection amount, in addition to the effect of the invention described in each claim, it becomes possible to further improve the detection accuracy of the fuel property, and the detected fuel property. By correcting the fuel injection amount according to the above, it is possible to further improve the combustibility and further improve the effect of improving exhaust emission.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a basic configuration diagram of the present invention.

FIG. 3 is a basic configuration diagram of the present invention.

FIG. 4 is a basic configuration diagram of the present invention.

FIG. 5 is a flowchart showing an initialization routine according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing the same heater control routine as above.

FIG. 7 is a flowchart showing a heater control routine (continued).

FIG. 8 is a flowchart showing a starter motor control routine of the above.

FIG. 9 is a flowchart showing a starter switch ON → OFF interrupt routine of the above.

FIG. 10 is a flowchart showing a fuel injection amount setting routine of the same as above.

FIG. 11 is an explanatory diagram of a table for detecting the weight ratio of the same as above.

FIG. 12 is a time chart showing the relationship between changes in heater current consumption and fuel properties, and the timing of initial fuel injection.

FIG. 13 is the same as above, and is an overall schematic view of the engine.

FIG. 14 is the same as the above, but is a detailed view of the heater mounting portion.

FIG. 15: Same as above, circuit configuration diagram of electronic control system

FIG. 16 is a flowchart showing a heater control routine according to the second embodiment of the invention.

FIG. 17 is a time chart showing the relationship between changes in heater current consumption and fuel properties, and the timing of initial fuel injection.

FIG. 18 is a flowchart showing a heater control routine according to the third embodiment of the present invention.

FIG. 19 is a flowchart showing the heater control routine (continued).

FIG. 20 is a flowchart showing a fuel injection amount setting routine of the same as above.

FIG. 21 (a) is an explanatory diagram of a table for detecting a heavy ratio when the alcohol concentration is 0%, and (b) is an explanatory diagram of a table for detecting a heavy ratio when the alcohol concentration is 100%. Figure

[Explanation of symbols]

1 Engine 22 Injector (fuel injection valve) 31 Heater unit (heater) 45 Current sensor 50 Electronic controller 67 Starter motor Tw Cooling water temperature (engine temperature) Tis First fuel injection pulse width (first fuel injection amount) I Heater consumption current ΔI heater Amount of change in consumption current E Fuel heavy ratio (fuel property) Ti Fuel injection pulse width (fuel injection amount after engine start permission)

Claims (5)

[Claims] 1. An engine in which a heater is provided opposite to a fuel injection direction of a fuel injection valve, a start inhibiting means for inhibiting the engine starting, a heater control means for energizing the heater after the engine starting is inhibited, and the heater Heater warm-up completion determining means for determining whether warm-up is completed, and after completion of warm-up of the heater, the initial fuel injection amount is set based on the engine temperature and the fuel of the initial fuel injection amount is supplied from the fuel injection valve. A first fuel injection amount setting means for injecting, a heater current consumption change amount detecting means for detecting a change amount of the heater current consumption due to the first fuel injection, a fuel property based on the heater current consumption change amount and the first fuel injection amount. A fuel property detection means for detecting fuel consumption, and an engine start permission means for permitting engine start after completion of the fuel property detection. Property detection device. 2. In an engine in which a heater is provided opposite to a fuel injection direction of a fuel injection valve, a start prohibiting means for prohibiting the engine start, a heater control means for energizing the heater after the engine start is prohibited, and a heater current consumption. And initial fuel injection start timing setting means for setting the start timing of the initial fuel injection based on the time after the start of energization of the heater before the completion of warm-up of the heater, and when the initial fuel injection start timing is reached, the initial fuel injection is started based on the engine temperature. Initial fuel injection amount setting means for setting a fuel injection amount and injecting fuel of the initial fuel injection amount from the fuel injection valve; and heater consumption current change amount detection for detecting a change amount of heater consumption current due to the initial fuel injection Means, fuel property detection means for detecting a fuel property based on the amount of change in the heater current consumption and the initial fuel injection amount, and warming up of the heater is completed. An engine fuel property detection device comprising: a heater warm-up completion determination means for determining whether the heater is warmed up; and an engine start permission means for permitting engine startup after the heater has been warmed up. 3. An engine in which a heater is provided opposite to a fuel injection direction of a fuel injection valve, a start inhibiting means for inhibiting engine starting, a heater control means for energizing the heater after the engine starting is inhibited, and the heater Heater warm-up completion determining means for determining whether warm-up is completed, and after completion of warm-up of the heater, the initial fuel injection amount is set based on the engine temperature and the fuel of the initial fuel injection amount is supplied from the fuel injection valve. A first fuel injection amount setting means for injecting, a heater current consumption change amount detecting means for detecting a change amount of the heater current consumption due to the first fuel injection, a fuel property based on the heater current consumption change amount and the first fuel injection amount. To detect the fuel property, engine start permission means to permit the engine to start after the completion of the fuel property detection, and the fuel injection amount after the engine start permission is increased. The fuel injection control device for an engine is characterized in that a fuel injection quantity setting means for setting correction to based on the fuel property. 4. In an engine in which a heater is provided opposite to a fuel injection direction of a fuel injection valve, a start prohibition means for prohibiting engine start, a heater control means for energizing the heater after prohibition of engine start, and a heater current consumption. And initial fuel injection start timing setting means for setting the start timing of the initial fuel injection based on the time after the start of energization of the heater before the completion of warm-up of the heater, and when the initial fuel injection start timing is reached, the initial fuel injection start timing Initial fuel injection amount setting means for setting a fuel injection amount and injecting fuel of the initial fuel injection amount from the fuel injection valve; and heater consumption current change amount detection for detecting a change amount of heater consumption current due to the initial fuel injection Means, fuel property detection means for detecting a fuel property based on the amount of change in the heater current consumption and the initial fuel injection amount, and warming up of the heater is completed. Heater warm-up completion determination means for determining whether or not, engine start permission means for permitting engine start after the heater has been warmed up, and fuel injection amount after engine start permission is corrected and set based on the fuel property A fuel injection control device for an engine, comprising: 5. A fuel property detecting device for an engine or a fuel injection control device for an engine according to claim 1, wherein the amount of change in the heater current consumption is corrected by the fuel temperature. .