JPH1182090A - Internal combustion engine control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the responsiveness and air-fuel ratio controllability of an electronically controlled fuel-injection type internal combustion engine by setting a target torque first and then the intake air quantity, fuel injection quantity and ignition timing all aimed at the torque. SOLUTION: A control system for an electronically controlled fuel-injection type internal combustion engine detects the running-state parameters of such an internal combustion engine to thus control the engine according to the driver' s engine running requests in consideration for these parameters. This control system detects the accelerator pedal travel with its accelerator pedal travel sensor 15 to thereby compute a target engine torque, at which controlled variables for the engine are aimed, including the necessary air quantity, necessary fuel quantity, required ignition timing and desired opening angle of an idle-speed control(ISC) valve 21. These variables are used for the control of an electronically controlled throttle 4, an injector 8, an igniter 16 and the ISC valve 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly, to a control device for controlling an operation state of the internal combustion engine, such as an intake air amount, a fuel injection amount, and an ignition timing, according to a target engine torque. The present invention relates to a control device for an internal combustion engine that is determined.

[0002]

2. Description of the Related Art Conventionally, a control device for an electronically controlled fuel injection type internal combustion engine, which replaces a carburetor type gasoline engine,
In order to obtain a required air-fuel ratio (A / F), the amount of intake air is controlled by a throttle valve that is mechanically connected to and linked with an accelerator pedal, and a fuel amount corresponding to the amount of air is determined. See the background section of the invention in Japanese Patent Publication No. Hei 7-33781). Then, the control device of the internal combustion engine measures the intake air amount determined by the throttle valve opening by a measuring device such as an air flow meter or a Kalman sensor, and determines a final control amount such as a fuel injection amount and an ignition timing corresponding to the measured intake air amount. Is generally calculated and output (for example, a method of controlling the fuel injection amount and the ignition timing of the internal combustion engine is disclosed in Japanese Patent Publication No. 7-94813).

In recent years, vehicles equipped with an electronically controlled fuel injection type internal combustion engine include, in addition to the standard equipment, an electronically controlled automatic transmission capable of changing a shift pattern according to a driver's preference. Cruise control device to run, traction control device to prevent idling of drive wheels,
In many cases, optional devices such as VSC (Vehicle Stability Control) are mounted. From these optional devices, that is, a request for adjusting the engine torque from a device other than the internal combustion engine may occur.
For example, the ignition timing retard amount is adjusted. Among the internal combustion engines equipped with these optional devices, there are cases where the throttle valve is electrically controlled in an internal combustion engine equipped with a traction control device, but this control is only for adjusting the intake air amount. .

[0004]

However, the conventional control device in the above-mentioned electronically controlled fuel injection type internal combustion engine has the following problems. (1) Since the fuel injection amount is calculated after the air amount is measured and the injection is performed, excess or deficiency of the fuel with respect to the intake air amount tends to occur during the acceleration / deceleration operation. As a countermeasure, correction control is performed by estimating the required fuel amount by a prediction method,
It is difficult to always control the internal combustion engine in an optimal state.

(2) Lean air-fuel ratio engine (lean burn engine)
For example, in the case where the target air-fuel ratio is set and controlled in a wide range, the air-fuel ratio is set by increasing or decreasing the fuel injection amount with respect to the intake air amount determined by the accelerator pedal operation amount of the driver. The engine torque changes with the air-fuel ratio set value. That is, even if the accelerator operation amount is constant, the driving force (torque) changes and drivability deteriorates.

(3) In an electronically controlled automatic transmission, in order to reduce the shift shock, a control is executed to lower the engine torque by instructing the engine control computer to retard the ignition timing at the time of shifting. However, in this case, the combustion is deteriorated by the retardation of the ignition timing, and the torque is reduced.
This is inefficient when viewed from the operating state of the engine. (4) In the vehicle equipped with the traction control device, retardation of the ignition timing and control of the opening of the sub-throttle valve are performed in order to reduce the engine torque during the traction control. The opening control of the sub-throttle valve is for reducing the amount of intake air to the engine such that when slippage occurs in the driving wheels, the torque becomes appropriate according to the friction coefficient of the road surface. However, as shown in (2), since the engine torque changes depending on the air-fuel ratio set value, it causes the traction control performance to vary.

Therefore, a first object of the present invention is to solve the problems of the conventional intake air amount advance control and fuel amount follow-up control method in an electronically controlled fuel injection type internal combustion engine, and to reduce the driver's operation amount of the accelerator pedal. First, a target engine torque (hereinafter simply referred to as a target torque) is determined on the basis of the target engine torque, and an intake air amount, a fuel injection amount, and an ignition timing are determined later so as to achieve the target torque. An object of the present invention is to provide a control device for an internal combustion engine that can improve controllability.

[0008] A second object of the present invention is to provide a system in which the torque adjustment request is added to the target torque even when a torque adjustment request is received from an optional device provided in the vehicle and affecting the operation state of the internal combustion engine. To correct the target torque,
An object of the present invention is to provide a control device for an internal combustion engine in which responsiveness and air-fuel ratio controllability of the engine are not impaired.

[0009]

The features of the present invention to achieve the above object are shown below as first to fourth inventions. According to a first aspect of the present invention, there is provided an electronic control system that includes an engine operating state parameter detecting unit and controls the engine to a required operating state in consideration of an operating state parameter in response to an engine operating request from a driver. A control device for a fuel injection type internal combustion engine, comprising: an accelerator pedal operation amount input means for inputting an accelerator pedal operation amount; and a torque amount to be generated by the internal combustion engine based on the input value of the accelerator pedal operation amount. And a means for determining a control amount of the internal combustion engine that determines a control amount of the internal combustion engine so as to achieve the calculated target torque amount.

According to a second aspect of the present invention, in the first aspect, the target torque amount calculating means generates the torque to be generated by the internal combustion engine based on a table of a preset accelerator operation amount and a target torque amount. Is to calculate the quantity. Third
According to a first aspect of the present invention, in the first or second aspect, the means for determining the control amount of the internal combustion engine includes, in addition to the target torque amount, a cooling water temperature, an atmospheric pressure, an intake air temperature, and other engine states. A target air-fuel ratio is calculated from input data, and an intake air amount, a fuel injection amount, and an ignition timing are output from the target air-fuel ratio as control amounts of the internal combustion engine.

A structural feature of the fourth invention is that in any one of the first invention to the third invention, an auxiliary component which is provided in addition to the main equipment of the engine and requires torque adjustment of the engine at the time of operation. Target torque amount correction means for correcting the target torque amount from the target torque amount calculation means in consideration of the required torque adjustment amount when there is an engine torque adjustment request from the equipment and the auxiliary equipment. And further comprising:

According to the first aspect, the internal combustion engine is controlled in accordance with the target torque amount determined in accordance with the operation amount of the accelerator pedal by the driver, so that the responsiveness and the air-fuel ratio controllability of the engine are improved. In the second aspect, since the target torque amount is calculated based on a table set in advance, the calculation time is short, and an accurate target torque amount can be obtained.

According to the third aspect, the target air-fuel ratio is calculated from the target torque amount, so that the responsiveness of the engine and the controllability of the air-fuel ratio are improved. In the fourth invention, when there is an engine torque adjustment request from the auxiliary equipment, the target torque amount from the target torque amount calculation means is corrected. Engine responsiveness and air-fuel ratio controllability are improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail based on specific examples with reference to the accompanying drawings.
Before describing an embodiment of the present invention, a schematic configuration of an electronically controlled fuel injection type internal combustion engine to which the present invention is applied and a conventional control in the electronically controlled fuel injection type internal combustion engine will be described with reference to FIGS. This will be described with reference to FIG.

FIG. 1 schematically shows an electronically controlled fuel injection type multi-cylinder internal combustion engine 1 provided with a control device according to one embodiment of the present invention. In FIG. 1, an intake passage 2 of an internal combustion engine 1 is shown.
The throttle valve 3 is located downstream of the air cleaner (not shown).
An idle speed control (hereinafter referred to as I) for adjusting an idle speed when the throttle valve 3 is closed is provided in the intake passage 2 before and after the throttle valve 3.
A passage 20 (described as SC) is provided to bypass the throttle valve 3. An ISC control valve 21 for adjusting the amount of intake air flowing through the ISC passage 20 is provided in the middle of the ISC passage 20.

An actuator 4 for driving the throttle valve 3 is provided at one end of the shaft of the throttle valve 3, and a throttle opening sensor 5 for detecting the opening of the throttle valve 3 is provided at the other end. . That is, the throttle valve 3 of this embodiment is an electronically controlled throttle valve that is opened and closed by the actuator 4. A surge tank 6 is provided in the intake passage 2 on the downstream side of the throttle valve 3, and a pressure sensor 7 for detecting intake pressure is provided in the surge tank 6.
And an intake air temperature sensor 18 for detecting the temperature of the intake air. The amount of intake air to the internal combustion engine 1 is calculated from the detected value of the pressure sensor 7 and is corrected by the detected value of the intake air temperature sensor 18.

Further, a fuel injection valve 8 for supplying pressurized fuel from a fuel supply system to an intake port is provided downstream of the surge tank 6 for each cylinder. The output of the throttle opening sensor 5, the output of the pressure sensor 7, and the output of the intake air temperature sensor 18 are E
It is input to a CU (engine control unit) 10.

The fuel injected from the fuel injection valve 8 is mixed with the intake air and enters the combustion chamber 23 when the intake valve 22 is opened.
The fuel is ignited by the ignition plug 25 in a state compressed by the piston 24 and burns, and the exhaust gas after the combustion is discharged to the exhaust passage 12 by the piston 24 when the exhaust valve 26 is opened. The spark plug 25 is sparked by an igniter 16 which is a current interrupting device and an ignition coil 17 which is a booster, and the ignition timing of the ignition plug 25 is determined by a signal from the ECU 10 to the igniter 16.

On the other hand, in the cooling water passage 9 of the cylinder block of the internal combustion engine 1, a water temperature sensor 11 for detecting the temperature of the cooling water is provided. The water temperature sensor 11 generates an analog voltage electric signal according to the temperature of the cooling water. The exhaust passage 12 contains three harmful components HC and C in the exhaust gas.
A three-way catalytic converter (not shown) for purifying O and NOx at the same time is provided. An O ₂ sensor 13 which is a kind of air-fuel ratio sensor is provided in an exhaust passage 12 on the upstream side of the catalytic converter. I have. The O ₂ sensor 13 generates an electric signal according to the concentration of the oxygen component in the exhaust gas. The outputs of the water temperature sensor 11 and the O ₂ sensor 13 are
Is input to

The ECU 10 further includes an accelerator opening signal indicating an accelerator depression amount from an accelerator depression amount sensor 15 attached to the accelerator pedal 14 and a reference crank angle G from a crank angle sensor 19 attached to the distributor. And a signal CA for each predetermined angle is input. The engine speed Ne is obtained by measuring the interval (time) of the signal CA for each predetermined angle.

In the above configuration, when a key switch (not shown) is turned on, the ECU 10 is energized to start a program, and the output from each sensor is taken in.
Control of the actuator 4 for opening and closing the throttle valve 3, the fuel injection valve 8, or other actuators is started. The ECU 10 includes an A / D converter for converting an analog signal from various sensors into a digital signal, and an input / output interface 10 for input and output of digital signals from various sensors and signals for driving each actuator.
1. CPU 102 for performing arithmetic processing, ROM 103 or RA
A memory such as M104, a clock 105 and the like are provided, and these are interconnected by a bus 106. E
Since the configuration of the CU 10 is publicly known, further description will be omitted.

Here, in the electronically controlled fuel injection type internal combustion engine configured as shown in FIG. 1, how the fuel injection valve (injector) 8, the igniter 16, and the ISC control valve 21 are conventionally controlled. Will be described with reference to FIG. However, in a conventional electronically controlled fuel injection type internal combustion engine, the throttle valve 3 is mechanically connected to the accelerator pedal 14, and the opening and closing of the throttle valve 3 is controlled according to the amount of depression of the accelerator pedal 14 by the driver. (Electronically controlled throttle valve) 4 for opening and closing the actuator is not employed.

In the prior art, the amount of intake air is determined by a driver operating a throttle valve mechanically connected to an accelerator pedal. The ECU 10, which is a control device for the internal combustion engine, includes an intake pipe pressure detected by the intake pipe pressure sensor 7, a throttle opening detected by the throttle opening sensor 5, and a crank angle sensor 19.
Thus, signals from various sensor switches, such as an engine speed and an intake air temperature sensor, are input, and the intake air amount is detected and predicted from these signals. Then, various control amounts (fuel increase / decrease amount, etc.) are calculated according to the detected intake air amount and the operating condition of the engine, for example, the cooling water temperature, etc., and the required fuel amount (fuel injection time) is output to the injector 8, and the required ignition The timing was output to the igniter 16, and the ISC control amount was output to the ISC control valve 21.

In the case of a lean burn engine, A / F = 2
Control is performed from a lean air-fuel ratio of about 5 to a stoichiometric air-fuel ratio or A / F = 13 which is an output air-fuel ratio, and the fuel injection amount is determined by calculation from the above-described air amount and air-fuel ratio. In addition, the ignition timing (ignition advance angle) is determined by the engine speed, the intake pipe pressure, and the like. Under idling conditions, the amount of air passing through the ISC control valve 21 is controlled to a predetermined speed.

In such a conventional control device for an internal combustion engine, the generated torque of the engine is determined by the intake air amount according to the depression amount of the accelerator pedal operated by the driver and the set air-fuel ratio. When an electronically controlled automatic transmission (ECT), a traction control (TRC) device, or the like is combined with such a system, a temporary ignition delay for the purpose of reducing a shock at the time of shifting the ECT can be used. Temporary torque reduction by reducing the intake air amount has been performed for the purpose of reducing the torque and suppressing idling of the drive wheels as in a TRC device.

As a result, as described above, (1) excess or deficiency of the fuel with respect to the intake air amount occurs during the acceleration / deceleration operation of the engine.
(2) In the case where the target air-fuel ratio is set and controlled in a wide range such as a lean burn engine, even if the accelerator operation amount is constant, the torque changes and the drivability deteriorates.
(3) In a vehicle equipped with an ECT, combustion is deteriorated due to an ignition timing retard command for reducing a shift shock at the time of an ECT shift, and efficiency is deteriorated. (4) In a vehicle equipped with a TRC device,
The torque at the time of driving wheel idling is determined by retarding the ignition timing and controlling the opening of the sub-throttle valve to reduce the torque during traction control, but the traction control performance varies due to the torque change due to the air-fuel ratio set value. , There was a problem.

On the other hand, in the control device for an internal combustion engine according to the present invention, the electronic control throttle 4, the injector 8, the igniter 16, and the ISC control valve 21 are controlled as shown in FIG. That is, in the present invention, the depression amount of the accelerator pedal operated by the driver is extracted as an electric signal by the accelerator depression amount sensor 15 and is input to the ECU 10 which is a control device of the internal combustion engine, and first, the target torque is calculated. You.

When the idling speed detected by the crank angle sensor 19 is controlled to the target speed, the target torque is used as an adjustment parameter, so that the control calculation after the target torque is unified. That is, in the present invention, various control amounts are calculated based on the engine speed Ne, the throttle opening from the throttle opening sensor 5, and signals from various sensors and switches so that the target torque is obtained. Then, according to the calculated control amount, the necessary intake amount (target throttle valve opening) output to the electronic control throttle valve 4, the required fuel amount (fuel injection time) output to the injector 8, and the output to the igniter 16 The required ignition timing 16 and the ISC valve opening output to the ISC control valve 21 are calculated. The intake pipe pressure information P detected by the pressure sensor 7 is input to the ECU 10 in order to correct a control error of the electronic control throttle valve 4.

Here, a control example in the control device for an internal combustion engine of the present invention configured as described above will be described with reference to the flowcharts of FIGS. FIG. 4 is a flowchart showing an example of the control procedure of the first embodiment in the control device for an internal combustion engine of the present invention. This control procedure is executed every predetermined time or every predetermined crank angle CA.

In step 401, accelerator opening data detected by the accelerator pedal depression amount sensor 15 is read. The accelerator opening data is fetched after A / D conversion by an A / D converter (not shown in FIG. 1) provided in the ECU 10. In the following step 402, the operation amount of the accelerator pedal 14 (hereinafter referred to as accelerator opening)
Is determined to be 0 or not.

In step 402, the accelerator opening is 0
If not, the routine proceeds to step 403, where the basic torque Trqb is calculated based on the accelerator opening, for example, from the table shown in FIG. FIG. 10A shows the relationship between the accelerator operation amount and the target torque amount, which is set in advance and stored in the ROM 103 in the form of a map. Data not on the map is read out by interpolation. However, since the minimum and maximum achievable torque values change according to the engine speed, the target torque value is limited by the values in the upper and lower limit value table shown in FIG. The basic torque Trqb is determined based on the accelerator opening, the engine speed,
Alternatively, it may be determined in relation to information such as the vehicle speed.

On the other hand, if the accelerator opening is 0 in step 402, the routine proceeds to step 404, where the basic torque Tr
qb is set to 0 Nm, and the routine proceeds to step 405. In step 405, the idle speed control torque Trqi is calculated. When the accelerator opening is zero, there are an idling state in which the vehicle speed is also zero and a decelerating operation state such as downhill traveling. Therefore, the calculation of the idle speed control torque Trqi in step 405 is performed in two cases, i.e., an idle control state and a deceleration state, as shown in the flowchart of FIG.

Therefore, when the routine proceeds to step 405, in step 501, the current engine speed Ne is set.
Is greater than or equal to the target idle speed + 400 rpm, and Ne ≧ (target idle speed + 400 rpm)
In the case of m), it is determined that the vehicle is in the deceleration state, and otherwise, it is determined that the vehicle is in the idle control state. If it is determined that the engine is in the idling control state, the process proceeds to step 502, where the idling speed control torque Trq is set to the target idling speed.
i is increased or decreased by the feedback control. That is, the idle speed control torque Trqi is increased or decreased so as to eliminate the deviation amount between the target idle speed and the actual speed.

When the internal combustion engine is provided with an air conditioner (air conditioner), the idling speed control torque Trqi at this time is different from the internal combustion engine when the air conditioner is operating. It is calculated based on the amount of load torque in consideration of the applied load. Step 502
Is calculated in step 503, this value is used as the stored value Trqim of the idle speed control torque in step 503 as the RA of the ECU 10.
It is stored in M104.

On the other hand, when it is determined in step 501 that the engine is in the decelerating state, the routine proceeds to step 504, where the latest stored value Trqim of the idle speed control torque stored in step 503 is used as the idle speed control torque Trq.
It is calculated as i. After the basic torque Trqb is calculated in step 403 shown in FIG. 4 or after the idle speed control torque Trqi is calculated in step 405, the process proceeds to step 406.

In step 406, the target torque Trq is calculated by adding the idle speed control torque Trqi to the basic torque Trqb. In the following step 407, the required fuel amount Gf is calculated from the target torque Trq. The required fuel amount Gf is obtained by storing data relating to the target torque, the engine speed, the target air-fuel ratio, and the like in advance in the ROM 103 in the form of a map.
And can be calculated using this map. At this time, the reason why the air-fuel ratio information is associated is that the same torque can be generated with a small amount of fuel due to a decrease in pumping loss or the like during the lean air-fuel ratio operation. Less is needed).

After the required fuel amount Gf is calculated in step 407, the routine proceeds to step 408, where the target air-fuel ratio A / F is determined according to the target torque Trq and operating conditions such as the engine speed. Then, in the next step 409, the required intake air amount Ga is obtained by multiplying the target air-fuel ratio A / F by the above-mentioned required fuel amount Gf. In the subsequent step, it is determined again whether or not the accelerator opening is 0. If the accelerator opening is not 0, the process proceeds to step 411, where the opening of the electronically controlled throttle valve is stored in the ROM 103 in advance according to the required intake air amount Ga. From the map. This map is
Data relating to the engine speed and the required intake air amount is obtained in advance and is formed into a map. On the other hand, the accelerator opening is 0
In step 412, the ISC control valve opening for the required intake air amount Ga is calculated from a previously stored characteristic map.

When step 411 or 412 is completed, the routine proceeds to step 413, where the fuel injection time that is output to the injector 8 from the required fuel amount Gf is calculated. The fuel injection time is calculated from the required fuel amount Gf (g / sec) in consideration of the flow rate characteristics of the injector, the engine speed, the fuel specific gravity, and the like. Then, in the following step 414,
The ignition timing is calculated from the required intake air amount Ga and the engine speed Ne. For this ignition timing, a map of the required intake air amount Ga and the engine speed is created in advance and stored in the ROM 103,
The ignition timing can be obtained by reading it out when necessary. In the last step 415, each actuator drive process is executed based on the calculated various control amounts.

In the embodiment described above, as shown in FIG. 6, the target torque Trq is calculated by the target torque calculation unit 10A from the sum of the basic torque Trqb calculated according to the accelerator pedal opening and the idle speed control torque Trqi. Had been calculated. On the other hand, vehicles equipped with an internal combustion engine
When an (electronically controlled automatic transmission) 27 and a TRC (traction control) device 28 are provided, E
The torque reduction request and the required torque value from the CT control computer and the torque reduction request and the required torque value from the TRC control computer are input to the target torque calculation unit 10A of the ECU 10.

In such a case, in step 406 of the flowchart described with reference to FIG.
q is calculated in consideration of the torque reduction request from the ECT 27 or the TRC 28. A procedure for calculating the target torque Trq in step 406 in this case will be described as a second embodiment of the present invention with reference to FIG. If the ECT 27 or TRC device 28 is mounted on the vehicle, step 406
When calculating the target torque Trq in, first, step 701 is executed, and it is determined whether or not there is a torque reduction request from the TRC device 28. If there is no torque reduction request from the TRC device 28, step 70
Proceeding to 2, it is determined whether or not there is a torque reduction request from the ECT 27.

If there is no torque reduction request from the TRC device 28 and the ECT 27, the routine proceeds to step 703, where the normal basic torque Trqb and the idle speed control torque Trq
The target torque Trq is calculated based on i. On the other hand, if there is a torque reduction request from the TRC device 28 in step 701, the process proceeds to step 704, and based on the torque reduction request from the TRC device 28 having a higher priority in vehicle control, the target torque Trq is set to the target torque Trq. Trq
t is substituted as it is. If it is determined in step 702 that there is a torque reduction request from the ECT 27, the process proceeds to step 705, where the ECT having a higher priority in vehicle control is selected.
27, the target torque Trq
Is substituted for the ECT required torque Trqe.

As described above, in the control device for an internal combustion engine of the present invention, when a torque reduction request is issued from another system,
The target torque Trq is changed to achieve the required torque, and the engine is controlled in an optimal state. Next, the operation of the control device for an internal combustion engine of the present invention at the time of switching the air-fuel ratio in a lean burn engine will be described with reference to FIG. Here, the accelerator pedal is operated by the driver to increase the accelerator opening from 0 from time t1, and the accelerator opening is maximized at time t3.
The case where the value returns to 0 at 5 will be described.

In the lean burn engine of this example, for example, the target torque calculated based on the accelerator opening is, for example,
The lean air-fuel ratio is controlled below the first set torque T1, and the stoichiometric air-fuel ratio is controlled above the second set torque T2 set slightly higher than the first set torque T1. It is assumed that When the accelerator opening increases and the target torque increases from time t1, the air-fuel ratio is controlled to the lean air-fuel ratio until the second set torque T2. Then, at time t2 when the target torque becomes equal to or greater than the second set torque T2, the air-fuel ratio is switched from the lean air-fuel ratio to the stoichiometric air-fuel ratio, and thereafter, the stoichiometric air-fuel ratio is maintained. On the other hand, when the accelerator opening is operated to the closing side after time t3 and the target torque decreases, at time t4 when the target torque falls below the first set torque T1, the air-fuel ratio becomes stoichiometric. The fuel ratio is switched to the lean air-fuel ratio.

The switching control of the air-fuel ratio in the lean burn engine is performed mainly by switching to the stoichiometric air-fuel ratio when the output is required to be higher than the maximum output torque in the lean air-fuel ratio operating state. Is generated by the stoichiometric air-fuel ratio. The required fuel amount in this case is determined according to the target torque, the target air-fuel ratio, the engine speed, etc., but changes substantially in proportion to the target torque, increases from time t1 to time t3, and increases from time t3 to time t5. To decrease. On the other hand, the required intake air amount is obtained by multiplying the required fuel amount by the target air-fuel ratio. In the lean air-fuel ratio control, the required intake air amount increases from time t1 to time t2 when the target air-fuel ratio switches from the lean air-fuel ratio to the stoichiometric air-fuel ratio, but as soon as the target air-fuel ratio is switched to the stoichiometric air-fuel ratio at time t2, It is reduced to the throttle opening corresponding to the air-fuel ratio,
The intake air amount sharply decreases by the difference of the air-fuel ratio. Thereafter, the required intake air amount continues to increase until time t3, and from time t3 to time t4.
Until the target torque decreases.

As described above, the sudden change in the required intake air amount between the time t2 and the time 4 is such that the required intake air amount at the time of the lean air-fuel ratio control is larger than that of the stoichiometric air-fuel ratio control by the difference of the air-fuel ratio. Because there is. Therefore, at the time of switching the air-fuel ratio, the required intake air amount changes rapidly. The actually generated torque tends to be substantially proportional to the required fuel amount. Therefore, since the required fuel amount is substantially proportional to the target torque, the control device for the lean burn engine of the present invention
It can be seen that a torque proportional to the driver's accelerator operation amount is generated regardless of whether the air-fuel ratio control state is the lean state or the stoichiometric air-fuel ratio state. Therefore, in a lean burn engine equipped with the control device for an internal combustion engine according to the present invention, torque is generated according to the accelerator operation amount of the driver, so that drivability is improved.

On the other hand, the operation of the conventional control device for the internal combustion engine in the lean burn engine when the accelerator operation similar to that in FIG. 8A is performed will be described with reference to FIG. 8B.
Here, when the target torque is equal to or less than the first set torque T1, the air-fuel ratio is controlled to the lean air-fuel ratio, and the second set torque T2 (> first
Above the set torque T1), the stoichiometric air-fuel ratio is controlled.

Therefore, even in the conventional control, the time t1
T when the target torque exceeds the second set torque T2
Up to 2, the air-fuel ratio is controlled to a lean air-fuel ratio. And
After the time t2, the air-fuel ratio is switched from the lean air-fuel ratio to the stoichiometric air-fuel ratio, and thereafter, the air-fuel ratio is maintained at the stoichiometric air-fuel ratio until the time t4 when the target torque becomes less than the first set torque T1. Thereafter, at time t4, when the target torque becomes equal to or less than the first set torque T1, the air-fuel ratio is switched from the stoichiometric air-fuel ratio to the lean air-fuel ratio, and thereafter, as long as the target torque does not exceed the second set torque T2. Lean air-fuel ratio is maintained.

In the conventional control, as described above, since the intake air amount precedes, when the accelerator opening changes, the throttle opening also changes accordingly, and the required intake air amount increases from time t1 to time t3. It decreases from t3 to time t5. In the conventional control, the required fuel amount is determined according to the target air-fuel ratio, the engine speed, and the like. Therefore, from time t1 to time t2, the required fuel amount increases with an increase in the intake air amount under the lean air-fuel ratio. When the target air-fuel ratio changes from the lean air-fuel ratio to the stoichiometric air-fuel ratio at time t2, the target air-fuel ratio sharply increases by the air-fuel ratio difference,
Thereafter, until time t4, the air-fuel ratio increases and decreases following the increase and decrease of the intake air amount under the stoichiometric air-fuel ratio. When the target air-fuel ratio changes from the stoichiometric air-fuel ratio to the lean air-fuel ratio at time t4, the air-fuel ratio sharply decreases by the difference of the air-fuel ratio, and thereafter increases and decreases following the increase and decrease of the intake air amount under the lean air-fuel ratio.

As described above, the sudden change in the required fuel amount between the time t2 and the time 4 is a value obtained by increasing the required fuel amount by the difference in the air-fuel ratio during the stoichiometric air-fuel ratio control with respect to the lean air-fuel ratio control. Because there is. Therefore, in the conventional control, the required fuel amount changes suddenly at the time of switching the air-fuel ratio. The actually generated torque tends to be substantially proportional to the required fuel amount as described above. Therefore, in the control device of the conventional lean burn engine, when the air-fuel ratio control state switches from the lean air-fuel ratio state to the stoichiometric air-fuel ratio state, the generated torque sharply increases, and the stoichiometric air-fuel ratio state switches to the lean air-fuel ratio state. At this point, the generated torque is sharply reduced. Therefore, in a lean burn engine equipped with a conventional control device for an internal combustion engine, the torque suddenly changes at the time of switching the air-fuel ratio during acceleration or deceleration by the driver's accelerator operation. bad.

The control example described above is a case where the lean burn engine does not have a torque adjustment request from another system.
7 and the TRC device 28, the target torque changes according to a torque adjustment request from these systems. The operation of the control device for an internal combustion engine of the present invention in a case where such a lean burn engine receives a torque adjustment request from another system will be described with reference to FIG. 9 together with switching of the air-fuel ratio. For the sake of simplicity, here, it is assumed that only the TRC device 28 is provided in the lean burn engine as another system, and the accelerator opening degree is changed from 0 at time ta by the driver's operation of the accelerator pedal. And the accelerator opening becomes maximum at time te,
An operation example when a torque reduction request is issued from the TRC device 28 in an operation state in which the accelerator opening is kept constant thereafter will be described.

Also, in the lean burn engine of this example, for example, the target torque calculated based on the accelerator opening is calculated as follows, for example.
The lean air-fuel ratio is controlled below the first set torque T1, and the stoichiometric air-fuel ratio is controlled above the second set torque T2 set slightly higher than the first set torque T1. It is assumed that When the accelerator opening increases from time ta and the target torque increases, the air-fuel ratio is controlled to a lean air-fuel ratio until the second set torque T2. Then, at time tb when the target torque becomes equal to or more than the second set torque T2, the target air-fuel ratio is switched from the lean air-fuel ratio to the stoichiometric air-fuel ratio.

On the other hand, at time tc after time tb, the target torque calculated from the accelerator opening is
It is assumed that idling occurs in the driving wheels of the vehicle. At this time, TR
A torque reduction request and a required torque value from the C control computer are input to the ECU 10. The required torque of the TRC is controlled such that a torque reduction request is generated upon detection of idling of the drive wheels so that the air-fuel ratio becomes a predetermined set value. Therefore, the required torque tends to increase as the vehicle speed increases.

In the example of FIG. 9, the target torque exceeds the second set torque T2 at time tb before the occurrence of idling of the drive wheels, and the air-fuel ratio switching condition is satisfied. In this case,
Immediately after switching control to the stoichiometric air-fuel ratio, the target torque decreases in response to a torque reduction request from the TRC control computer. Then, at time td, the target torque becomes the first torque.
, The switching condition to the lean air-fuel ratio is satisfied again, so that the target air-fuel ratio is switched from the stoichiometric air-fuel ratio to the lean air-fuel ratio.

At time te thereafter, when the air-fuel ratio reaches a predetermined set value due to a torque reduction request from the TRC control computer, the required TRC torque increases as the vehicle speed increases. Then, when the TRC required torque becomes the second set torque at the subsequent time tf, the target air-fuel ratio is switched from the lean air-fuel ratio to the stoichiometric air-fuel ratio. After this, T
The RC required torque continues to increase, and at time tg, the TRC required torque matches the basic torque.

The required fuel amount in this case changes substantially in proportion to the target torque, increases from time ta to time tc, decreases from time tc to time te, and then increases again from time te to time tg. On the other hand, since the required intake air amount is obtained by multiplying the required fuel amount by the target air-fuel ratio, it changes according to the change in the required fuel amount and the change in the target air-fuel ratio. Therefore,
The required intake air amount increases with a change in the required fuel amount from time ta to time tb, but sharply decreases by the difference in the air-fuel ratio due to a change in the target air-fuel ratio at time tb. From time tb to time td, the required intake air amount increases with a change in the required fuel amount and then decreases, and suddenly increases by the air-fuel ratio difference due to the switching of the target air-fuel ratio at time td.
From d to time tf, it decreases and then increases with a change in the required fuel amount. Then, at the time of switching of the target air-fuel ratio at the time tf, the difference between the air-fuel ratios sharply decreases, and at the time tf
Thereafter, it changes according to the change in the required fuel amount.

Since the actually generated torque is substantially proportional to the required fuel amount and the required fuel amount is substantially proportional to the target torque, in the lean burn engine control device of the present invention, the air-fuel ratio control state is set to the lean state. Regardless of the stoichiometric air-fuel ratio state,
It can be seen that a torque is generated in which a torque adjustment request from the TRC device is added to the torque proportional to the accelerator operation amount of the driver. Therefore, in the lean burn engine equipped with the control device for an internal combustion engine of the present invention, the generated torque can be continuously controlled irrespective of the change in the target air-fuel ratio, which adversely affects the controllability of the TRC device. The lean burn engine can be operated in the best condition without any trouble.

On the other hand, when the lean burn engine equipped with the TRC control device is controlled by the conventional control device for the internal combustion engine of the intake air amount advance control and the fuel amount follow-up control system,
The required intake air amount changes following the change in the target torque. The required fuel amount increases by the difference between the lean air-fuel ratio of the target air-fuel ratio and the stoichiometric air-fuel ratio at the time tb and the time tf at the time of switching from the stoichiometric air-fuel ratio of the target air-fuel ratio at the time td to the lean air-fuel ratio. At the time of switching to the mode, the air-fuel ratio decreases by the difference.

As a result, the torque actually generated, which is substantially proportional to the required fuel amount, rapidly increases or decreases following the required fuel amount that changes at the time of switching the target air-fuel ratio. Therefore, in the conventional control device, when the control state of the target air-fuel ratio switches between the lean state and the stoichiometric air-fuel ratio state, a sudden change in torque occurs. Therefore, in a lean burn engine equipped with a conventional control device for an internal combustion engine, the generated torque changes every time the target air-fuel ratio changes, so that TR
The controllability of the C device is adversely affected, and the lean burn engine cannot be operated in the best condition.

The embodiment described above is a basic embodiment of the present invention. In addition to the target air-fuel ratio, various control amount calculations for the target torque corresponding to the variable control elements of the internal combustion engine control are performed by controlling the internal combustion engine. It shall be executed by the device. Also,
The variable elements include the ECT 27 and the TRC device 28 described above.
In addition, for example, an intake flow control device (SCV device, VV
T device, variable intake device, etc.), and supercharger (T / C, S /
C) and the like. As other control systems, there are control systems such as cruise control and VSC.

In the above embodiment, the lean burn engine has been described. However, the engine to which the control device for an internal combustion engine of the present invention is applied is not particularly limited to the lean burn engine. As described above, the internal combustion engine control device of the present invention operates using the target torque to be generated by the internal combustion engine as a parameter.
For example, regardless of the difference between the full range stoichiometric air-fuel ratio control engine and the lean burn engine, control can be performed at the best point of the engine characteristics, and the output engine torque is always proportional to the driver's accelerator operation amount. can get.

Also, comprehensive torque control can be performed with another control system using the required torque as a parameter.
This is particularly effective when a plurality of engines are combined with the same vehicle. The control target amount of a TRC device or the like is determined from vehicle characteristics, and the control target amount of ECT is determined from transmission characteristics. Conventionally, for each of the plurality of combinations, the throttle opening adjustment amount and the control amount of the ignition timing retard amount have been experimentally set and confirmed, and matching has been carried out for a long time. However, according to the present invention, the required control amount may be determined for one type of combination, and even if engines of different types are combined, the control amount of the system other than the internal combustion engine such as the TRC device and the ECT is not affected.

Therefore, according to the control apparatus for an internal combustion engine of the present invention, when constructing a large-scale vehicle control system such as a more complicated internal combustion engine and integrated vehicle control, each system has an independent system. Can be developed, and the control accuracy of each system can be guaranteed.

[0063]

As described above, the control device for an internal combustion engine according to the present invention has the following effects. In the first aspect, the internal combustion engine is controlled according to the target torque amount determined according to the operation amount of the accelerator pedal by the driver, so that the responsiveness and the air-fuel ratio controllability of the engine are improved.

In the second aspect, the target torque amount is calculated based on a table set in advance, so that the calculation time is short and an accurate target torque amount can be obtained. In the third aspect, since the target air-fuel ratio is calculated from the target torque amount, the responsiveness of the engine and the controllability of the air-fuel ratio are improved. In the fourth invention, when there is an engine torque adjustment request from the auxiliary equipment, the target torque amount from the target torque amount calculation means is corrected.
Engine responsiveness and air-fuel ratio controllability are improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an entire configuration of an embodiment of an electronically controlled fuel injection type internal combustion engine including a control device for an internal combustion engine of the present invention.

FIG. 2 is a block diagram showing the operation of a conventional control device for an internal combustion engine.

FIG. 3 is a block diagram showing the operation of the control device for an internal combustion engine of the present invention.

FIG. 4 is a flowchart illustrating an example of a control procedure of the first embodiment in the control device for the internal combustion engine of the present invention.

FIG. 5 is a flowchart showing a detailed procedure of step 405 in FIG. 4;

FIG. 6 is a block diagram showing an example of a torque adjustment request from another system in FIG. 3;

7 is a flowchart showing details of the procedure of step 406 in FIG. 4 when there is a torque adjustment request from another system shown in FIG. 6;

8A is a time chart showing a change in generated torque with respect to a change in the accelerator opening according to the control procedure of the present invention shown in FIG. 4, and FIG. 8B is a conventional time chart showing a change in the accelerator opening similar to FIG. 6 is a time chart showing a change in torque generated by control.

FIG. 9 is a graph showing a change in generated torque with respect to a change in accelerator opening of the present invention when a torque adjustment request is issued from the traction control device shown in FIG. It is a time chart shown in comparison.

FIG. 10A is a table showing a relationship between an accelerator operation amount for calculating a target torque and a target torque amount, and FIG.
Is a table in which the upper and lower limits of the target torque amount with respect to the engine speed are set.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Intake passage 3 ... Throttle valve 4 ... Actuator 5 ... Throttle opening sensor 7 ... Pressure sensor 8 ... Fuel injection valve 10 ... ECU (Engine control unit) 11 ... Water temperature sensor 12 ... Exhaust passage 13 ... O ₂ sensor 14 ... accelerator pedal 15 ... accelerator depression amount sensor 16 ... igniter 17 ... ignition coil 18 ... intake air temperature sensor 19 ... crank angle sensor 20 ... ISC passage 21 ... ISC control valve

Claims (4)

[Claims] 1. An electronically controlled fuel injection type internal combustion engine comprising: means for detecting an operating state parameter of an engine; and controlling the engine to a required operating state by taking into account the operating state parameter in response to an engine operating request from a driver. An engine control device, comprising: an accelerator pedal operation amount input means for inputting an accelerator pedal operation amount; and a target torque for calculating a torque amount to be generated by the internal combustion engine based on the input value of the accelerator pedal operation amount. A control device for an internal combustion engine, comprising: an amount calculation unit; and a control amount determination unit for an internal combustion engine that determines a control amount of the internal combustion engine so as to achieve the calculated target torque amount. 2. The control device for an internal combustion engine according to claim 1, wherein said target torque amount calculating means should generate the internal combustion engine based on a table of a preset accelerator operation amount and a target torque amount. A control device for an internal combustion engine that calculates a torque amount. 3. The control device for an internal combustion engine according to claim 1, wherein the control means for determining the control amount of the internal combustion engine includes a cooling water temperature, an atmospheric pressure, and an intake air temperature in addition to the target torque amount. A control device for an internal combustion engine that calculates a target air-fuel ratio from input data of other engine states and outputs an intake air amount, a fuel injection amount, and an ignition timing from the target air-fuel ratio as control amounts of the internal combustion engine. 4. The control device for an internal combustion engine according to claim 1, wherein the auxiliary device is provided in addition to a main component of the engine and requires torque adjustment of the engine during operation. Target torque amount correction means for correcting the target torque amount from the target torque amount calculation means in consideration of the required torque adjustment amount when there is an engine torque adjustment request from the auxiliary equipment. And a control device for an internal combustion engine further comprising: