JPS60159338A - Engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent a misfire from occurring without fail, by driving a supercharger's rotor, having a lot of gas passages piercing through in a turning axial direction, with an electric motor in order to reduce a ratio between a rotor revolution and an engine speed in times of engine cooling and light load. CONSTITUTION:When an engine 1 is started, a motor 28 is rotated by output of power out of a control circuit 29, turning a rotor 15 of a supercharger 11. If so, suction air flows into a gas passage 16 inside the rotor 15 from a suction passage 22, and discharged to a supercharging passage 9 when the said passage 16 is opened to a suction discharge port 20, thus led into a combustion chamber 12. On the other hand, exhaust out of an exhaust port 6 is discharged to a discharge passage 21 by way of each of routes 10-17-16-18. At this juncture, when cooling water temperature by a water temperature sensor 38 is less than the specified value and engine load to be obtained from the output of an accelerator step-on extent sensor 32 is in a light-load state, a signal out of the control circuit 29 is made so as to be compensated by a compensation circuit 31 in order to reduce a ratio between a rotor revolution and an engine speed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a supercharged engine, particularly a pressure wave system in which intake air is compressed by exhaust pressure generated in an engine exhaust passage and introduced into a combustion chamber. Regarding engines equipped with superchargers.

(Prior Art) Pressure wave superchargers have been proposed for a long time, in which intake air is compressed using the exhaust pressure generated in the engine exhaust passage, and this compressed intake air is introduced into the combustion chamber. ,
Compared to a turbocharger using an exhaust turbine, it has recently been attracting attention again due to its high supercharging effect during low-speed operation. This type of supercharger consists of a rotor having a large number of gas passages separated from each other passing through the rotation axis, a case that rotatably supports the rotor around the rotation axis, and a case that supports the rotor rotatably around the rotation axis. An exhaust inlet, an exhaust outlet, and an intake inlet and an intake outlet are formed at positions facing the end of the rotor, and the intake air introduced into the gas passage in the rotor from the intake inlet is introduced from the exhaust inlet. It is configured to be pushed toward the intake/discharge port by the pressure of the exhaust gas.

For this reason, the exhaust gas inlet and the air intake and discharge ports are formed at positions opposite to each other in the rotor axial direction with the rotor sandwiched therebetween. An example of this type of pressure wave supercharger is the Utility Model 55-/Core 5
It is disclosed in Publication No. 39. In the turbocharger disclosed in this publication, an exhaust inlet and an exhaust outlet are provided on the same rotor end side, an intake inlet and an intake outlet are provided on the other rotor end side, and an exhaust This is a so-called counter-flow type in which the air flow and the intake air flow each change their flow direction within the rotor.
K so that these gases flow axially through the rotor.
The once-through type is also known, and its structure and operation are as follows:
Magazine [Internal Combustion Engine J Vol, /j, Jf6 /79. /
974. It is detailed in A.

This pressure wave supercharger is considered to be particularly suitable for diesel engines and is effective even at low speeds, but because the intake air is brought into contact with the exhaust air in the rotor, partial mixing of the intake air and exhaust air occurs. become.

This mixing can be considered as an exhaust gas recirculation (hereinafter referred to as EGR) effect, and the mixing ratio can be controlled by changing the rotation speed of the rotor.

(Object of the Invention) An object of the present invention is to focus on the phenomenon of the above-mentioned mixture of exhaust gas into the intake air that occurs in the pressure wave supercharger in an engine equipped with a pressure wave supercharger of the type described above, and to improve the rotation of the rotor. It is an object of the present invention to provide a diesel engine with a pressure wave supercharger that can effectively prevent misfires by increasing the amount of EGR during low-temperature, low-load operation by controlling the number of EGRs.

(Configuration of the present invention) In order to achieve the above object, the present invention has the following configuration.

That is, the supercharged engine according to the present invention includes a pressure wave supercharger, and the pressure wave supercharger includes a rotor having a large number of mutually separated gas passages passing through it in the direction of the rotation axis. , a case that rotatably supports the rotor around its rotating shaft; the case has an exhaust inlet connected to the engine exhaust port and an exhaust inlet connected to the engine exhaust port at a position facing the end of the rotor; An exhaust discharge port is formed to be offset in the rotational direction of the rotor, and an intake discharge port connected to the engine intake port is located on the opposite side of the rotation axis direction from the exhaust introduction port, and an exhaust discharge port is formed to be offset from the rotor rotation direction. Intake inlets for sucking atmospheric air are formed at positions opposite to each other in the direction of the rotation axis. In the present invention, an electric motor is provided to rotationally drive the rotor of the supercharger, and the rotation speed of the electric motor is set such that the engine rotation speed is set when the engine temperature is low and the engine is lightly loaded, or when the EGR1k increases. Control the ratio to the number small.

In a pressure wave supercharger, when the gas passage in the rotor opens to the exhaust inlet as the rotor rotates, exhaust pressure is transmitted to this gas passage, creating a pressure wave on the exhaust passage side of the gas passage. This pressure wave is generated and propagates within the passage at the speed of sound, compressing the intake air in the passage before reaching the other end. Therefore, by appropriately determining the positional relationship between the exhaust inlet and intake outlet, the length of the gas passage in the rotor, the rotational speed of the rotor, etc., the pressure waves propagating in the gas passage can be transmitted to the intake inlet. This allows a supercharging effect to be obtained. On the other hand, the flow of exhaust gas in the gas passage moves through the passage with a delay from the pressure waves, so if the gas passage is blocked from the intake/discharge port before the exhaust flow reaches the other end of the gas passage, the engine intake Exhaust air rarely mixes with the air.

Generally, due to the relationship with the engine intake air amount, it is normal to increase or decrease in proportion to the rotor rotational speed and the engine rotational speed. However, if the rotor speed is controlled so that the ratio of the rotor speed to the engine speed is small in an engine operating range where exhaust gas recirculation is required, for example, one exhaust gas will be exhausted before the gas passage is blocked from the intake and discharge ports. flows through the gas passage and mixes with the intake air, producing the effect of increasing the amount of EGR.

(Effects of the Invention) In the present invention, the rotor of the pressure wave supercharger is driven by an electric motor, and when the engine with poor ignition performance is at low temperature and under light load, the electric motor drives the rotor so that the amount of EGR increases. The ratio between the rotation speed of the engine and the rotation speed of the engine is controlled to be small. The drop K suppresses a decrease in intake air temperature and prevents misfires in the above-mentioned operating range.

According to the present invention, there is no need to provide a special EGR device such as an EGR passage in order to obtain the above-mentioned better EGR characteristics. Furthermore, compared to the case where the rotor is driven by the engine crankshaft, there are no restrictions on the mounting position of the supercharger, and flexibility in component arrangement is increased.

(Example theory BA) Basic configuration Referring to FIG. 1, an engine 1 has a cylinder 2 and a cylinder head 3 attached to the upper end of the cylinder 2, and a piston 4 inside the cylinder 2 can freely reciprocate. is arranged to form a combustion chamber 12 within the cylinder 2. An intake port 5 and an exhaust port 6 are formed in the cylinder head 3, and an intake valve 7 and an exhaust valve 8 are arranged in the intake port 5 and the exhaust IJ6, respectively. Further, the intake port 5 and the exhaust port 6 are connected to a supercharging passage 9 and an exhaust passage 10, respectively. A pressure wave supercharger 11 is provided between the supercharging passage 9 and the exhaust passage 10.

The supercharger 11 consists of a case 14 shown in FIG. 2(a) and a rotor 15 shown in FIG. As shown in FIG. 2 (6), the rotor 15 has a number of gas passages 16 that extend through it in the axial direction and are separated from each other. The case 14 has end walls j4as14bt- opposed to both ends of the rotor 16, one end wall 14a having an exhaust inlet 17 and an exhaust outlet 18 formed therein, and the other end wall 14b having an intake inlet 19 and an exhaust outlet 18 formed therein. An intake/discharge port 20 is formed. As shown in FIG. 1, an exhaust passage 10 is connected to the exhaust gas introduction port 17 of the case 14, and a supercharging passage 9 is connected to the intake and discharge port 20. Furthermore, an exhaust passage 21 is connected to the exhaust outlet 18 of the case 14, and an intake passage 22 is connected to the intake inlet 19.

A drive shaft 23 is fixed to the rotor 15, and this drive shaft 23
extends axially outward from one end of the rotor 15. The drive shaft 23 is rotatably supported in the intake housing 26 by bearings 24, 25, and cantilevers the rotor 15 at one end thereof.

The other end of the drive shaft 23 is coupled to an output shaft of an electric motor 28 via an electromagnetic clutch 27. A control circuit 29 is provided to control the rotation of motor 28. This control circuit 29 receives the output of the engine rotation speed sensor 30 as an input, and generates an output proportional to the engine rotation speed. For example, if the electric motor 28 is a pulse motor, the control circuit 29 generates a pulse output whose number of pulses increases in proportion to an increase in engine speed. The output of the control circuit 29 is input to a correction circuit 31, and the output of the correction circuit 31 is used to drive the motor 28. The correction circuit 31 receives the output of the operating amount of the engine control member, for example, the accelerator pedal depression amount sensor 32, and compares the voltage conversion value of the engine load with the set voltage input value 35 to determine whether the engine is in a light load state. A signal from a light load determination circuit 36 that determines this is input. The correction circuit 31 is
In response to the signal from the light load determination circuit 36, the output of the control circuit 29 is corrected to control the rotation speed of the remoter 28. In this example, a water temperature sensor 38 that detects the temperature of engine cooling water is provided in order to detect the temperature state of the engine, and a signal from this water temperature sensor 38 is also input to the light load determination circuit 36. ing. With this configuration, the correction circuit 31 adjusts the supercharger rotation speed C when the engine cooling water temperature is below a predetermined temperature and the engine is under a light load.
The signal from the control circuit 29 is corrected so that the rotation speed ratio CR/ER between R and the engine rotation speed ER becomes small. Third
() and () in the figure show the relationship between the engine fuel injection amount Q1, the rotational speed ratio CR/ER, and the EGR amount.

Figure 3) shows the case where the engine cooling water temperature is above a predetermined value, that is, after the engine has been warmed up, and the rotation speed ratio CR/ER is also always constant as shown by the solid line. The EGR amount at this time varies depending on the fuel injection amount Q, that is, the engine load, as shown by . When the load is low, a small amount of EGR is performed.

In addition, Fig. 3 @) shows a case where the engine cooling water temperature is below a predetermined value, that is, during warm-up, and the above-mentioned rotation speed ratio C
R/E R is smaller when the engine load is low than when the load is high, as shown by the solid line in the same figure, and the EGR amount at this time is as shown in Figure 3, as shown by the broken line in the same figure. ), the number of cases is increasing. Note that the output of the accelerator depression amount sensor 32 is also given to the electromagnetic clutch 27, so that the clutch 21 is disconnected in a load range smaller than a certain load.

In the load range when the operating engine 1 is started and the clutch 27 is engaged, the motor 28 is rotated by the output from the correction circuit 31 and drives the rotor 15 . Engine intake air flows from the intake passage 22 to the rotor 15 via the intake inlet 19.
The air enters the gas passage 16 in the
When it opens, it is discharged into the supercharging passage 9 and introduced into the combustion chamber 12 through the intake port 5. On the other hand, the exhaust gas discharged from the exhaust port 6 passes through the exhaust passage 10, enters the gas passage 16 in the rotor 15 from the exhaust introduction port 17, and is discharged into the exhaust passage 21 when the passage 16 opens to the exhaust discharge port 18. be done.

In the case 14, the exhaust inlet 17 and the intake outlet 20 are disposed at positions facing each other in the axial direction, so that the gas passage 1
When one end of 6 opens to the exhaust inlet 17, the core passage 16
The pressure waves generated within the passageway 16 propagate within the passageway 16.
The intake air reaches the intake air outlet 20 while being compressed, and is discharged into the passage 9 in a supercharged state.

FIG. 4 schematically shows the flow of intake and exhaust air in the passage 16 of the rotor 15. As shown in FIG. In the figure, the rotor 15 is shown unfolded for convenience of explanation, and the passage 16 moves from top to bottom in the direction indicated by arrow A as the rotor 15 rotates. The passage tea near the top of the figure moves in a state filled with intake air, and at the position of this passage lea, both ends of the passage are closed, so the spontaneous intake is in a stationary state. . One end of the continuing passage 16b opens to the exhaust gas introduction port 17, and pressure waves due to the exhaust gas are generated as shown at 33 in the figure. At this time, the exhaust gas is flowing into one end of the passage 16b as shown at 34. In the passages 16c and 16d whose phase is advanced in the rotational direction of the rotor 15, pressure waves of 33
The exhaust gas propagates as shown at 34a, 33b, and 34a,
As shown at 34b, the air is moving along the passage, but at this point the other end of the passage is closed and the intake air near the end is stationary. Further, in the passage lee, the end of the passage opens to the intake/discharge port 20, and at this point, the pressure wave reaches the intake/discharge port 20, and the selected intake is in the supercharged state and the passage 9
is discharged. Continuing passages 16 f, 16 g, 18 h
In this case, the intake air continues to be discharged, and the exhaust gas flows in the passage in the outflow direction of the intake air. The passage 161 is blocked from the exhaust gas introduction port 17, and an exhaust stationary portion 34c is created at the end on the side of the gas introduction port 17. The passage 16J is also cut off from the intake/discharge port 2°, so that the intake and exhaust are in a stationary state.

In the passage 18, one end of the passage opens to the exhaust discharge port 18, and an expansion part 35 of exhaust gas is generated at the end, and this expansion part expands within the passage as the phase advances, as shown in the figure. It's expanding. The other end of the passage 161 opens to the intake port 19 , atmospheric pressure air flows into the passage, and the expanded exhaust gas is pushed out to the exhaust passage 21 .

At the rotational speed of the rotor 15 shown in FIG. 9, the axillary passage 16 is blocked from the intake/discharge port 20 before the exhaust gas flowing into the passage 16 reaches the intake/discharge port 20. Therefore, the exhaust is
Except for a small amount of particles that remain mixed into the intake air due to contact with the intake air, they do not reach the supercharging passage 9. Fifth
The figure shows a case where the rotational speed of the rotor 15 is relatively lowered and the ratio between the rotor rotational speed and the engine rotational speed is reduced. In this state, the gas passage 1 due to the rotation of the rotor 15
6, the flow of the exhaust gas 34 is faster than the flow of the exhaust gas 34, and the exhaust gas 34 reaches the outlet 2o before the passage 16 is blocked from the intake outlet 2o.
0 and is discharged into the supercharging passage 9.

The amount of exhaust gas discharged into the supercharging passage 9 in this way changes depending on the ratio between the rotation speed of the rotor 15 and the engine rotation speed, and this rotation speed ratio is changed as shown by the solid line in Fig. 3 @). Then, the amount of exhaust gas mixed into the intake air changes as shown by the broken line in the figure. That is, by controlling the rotation speed of the pressure wave supercharger, it is possible to substantially control the EGR amount to a desired state. In this example, when the engine cooling water temperature is lower than a certain value in a region where the fuel injection amount is relatively small, that is, in a light load region, the rotation speed ratio CR/ER between the supercharger rotation speed and the engine rotation speed is It is controlled to be small, and a large amount of EGR can be obtained. This suppresses a decrease in intake air temperature, improves ignition performance, and prevents misfires. In addition, in the high load operation region, the rotation speed ratio C
A high supercharging effect can be obtained by increasing R/1-Rt and preventing the exhaust gas from being mixed into the intake air as shown in FIG.

Note that in the low-load operating range, the shift latch 27 may be turned off in response to a signal from the sensor 32, and the rotor 15 may be driven only by exhaust energy.

Further, although the above-mentioned embodiments are of the reverse flow type, the present invention can also be applied to the once-through type without any problem.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a supercharged engine showing an embodiment of the present invention, Fig. 2(a) and ←) are perspective views showing the case and rotor of the supercharger, and Fig. 3) and (B)
1 is a diagram showing an example of rotor rotational speed control, and FIGS. DESCRIPTION OF SYMBOLS 1... Engine, 9... Supercharging passage, 1o... Exhaust passage, 11... Supercharger, 14... Case, 15...
... Rotor, 16... Gas passage, 17... Exhaust inlet, 18... Exhaust discharge port, 19... Intake inlet, 2
0... Intake/discharge port, 28... Electric motor, 29.
...Control circuit diagram 114 A

Claims (1)

[Claims] A rotor having a plurality of gas passages separated from each other passing through the rotation axis direction, and a case rotatably supporting the rotor around the rotation axis, the case including an end portion of the rotor. An exhaust inlet port connected to the engine exhaust port and an exhaust discharge port for discharging exhaust gas into the atmosphere are formed at positions facing each other in the direction of rotation of the rotor, and are located opposite to the exhaust inlet port in the direction of the rotational axis. A pressure wave waveform of a type in which an intake discharge port connected to the engine intake port is formed at a side position, and an intake inlet port for sucking atmospheric air is formed at a position opposite to the exhaust discharge port in the rotation axis direction. In a supercharged diesel engine equipped with a feeder, an electric motor for rotationally driving the rotor, and a ratio of the rotation speed of the rotor to the engine rotation speed are reduced when the engine temperature is low and the engine is under light load. A supercharged engine characterized by being provided with a control device that controls the operation of the supercharged engine.