Control device of engine with supercharger

Abstract

To provide a control device of an engine with a supercharger, securing excellent sport sound.SOLUTION: A control device of an engine with a supercharger controls the ignition timing, injection quantity, and intake air amount of the engine with the supercharger loaded on a vehicle, and controls a wastegate valve disposed in a bypass passage bypassing a turbine of the supercharger. The control device of the engine with the supercharger executes torque-down control of retarding the ignition timing, when shifting from accelerator ON to accelerator OFF, by reducing the injection quantity and the intake air amount while opening the wastegate valve, and executes exhaust air sound control of further retarding the ignition timing until the finish of a top dead point between a compression stroke and an expansion stroke, and opening the wastegate valve.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device for a turbocharged engine. [Background technology]

[0002] There is a technology that significantly retards the ignition timing of the engine when transitioning from accelerator on to accelerator off, thereby increasing the exhaust sound and obtaining a good sporty sound (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-074885 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a turbocharged engine, if the above control is executed with the wastegate valve closed, the exhaust sound will be attenuated by the turbocharger turbine, and it may not be possible to obtain a good sporty sound.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a control device for a supercharged engine that ensures a good sporty sound. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a turbocharged engine that controls the ignition timing, fuel injection amount, and intake air amount of a turbocharged engine mounted on a vehicle, and also controls a wastegate valve provided in a bypass passage that bypasses the turbine of the turbocharger, and when the accelerator is shifted from on to off, executes torque down control that retards the ignition timing by closing the wastegate valve and reducing the fuel injection amount and intake air amount, and then executes exhaust sound control that further retards the ignition timing to after top dead center between the compression stroke and the expansion stroke, and opens the wastegate valve. Effect of the Invention

[0007] According to the present invention, it is possible to provide a control device for a supercharged engine that ensures a good sporty sound. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle. [Diagram 2] 4 is a timing chart illustrating the torque down control and the exhaust sound control executed by the ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Vehicle outline] FIG. 1 is a schematic diagram of a vehicle 100. The vehicle 100 includes a turbocharged engine (hereinafter simply referred to as an engine) 1, an intake passage 3, an exhaust passage 4, a turbocharger 5, an intercooler 6, a catalyst 7a, a filter 7b, a bypass passage 8, a wastegate valve 9, a transmission 21, a differential 23, wheels 25, and an ECU (Electronic Control Unit) 30. The engine 1 may be a gasoline engine or a diesel engine. The driving force of the engine 1 is transmitted to the wheels 25 via the transmission 21 and the differential 23. The vehicle 100 is an engine vehicle equipped with the engine 1 as a driving source. However, the vehicle 100 may be a hybrid vehicle equipped with a motor in addition to the engine 1 as a driving source.

[0010] The engine 1 has four cylinders 2, but the number of cylinders is not limited to this. Each cylinder 2 is provided with a fuel injection valve 2a and an ignition plug 2b. An intake passage 3 and an exhaust passage 4 are connected to the engine 1. A compressor 5b of a supercharger 5 is disposed in the intake passage 3. A turbine 5a of the supercharger 5 is disposed in the exhaust passage 4. The turbine 5a and the compressor 5b are coaxially connected by a shaft. The supercharger 5 supercharges the intake air to the engine 1.

[0011] A bypass passage 8 that bypasses the turbine 5a and a wastegate valve 9 that opens and closes the bypass passage 8 are provided in the exhaust passage 4. The opening degree of the wastegate valve 9 is adjusted by an electric actuator 9a that drives the wastegate valve 9. The opening degree of the wastegate valve 9 is feedback controlled by the ECU 30 so that the boost pressure becomes a target boost pressure that is determined according to the operating state of the engine 1. The ECU 30 outputs a command value to the electric actuator 9a to control the opening degree of the wastegate valve 9. The wastegate valve 9 is a normally closed type that is fully closed when the electric actuator 9a is not energized.

[0012] An intercooler 6 for cooling the intake air is disposed downstream of the compressor 5b in the intake passage 3. A throttle valve 3a for adjusting the amount of intake air of the engine 1 is disposed downstream of the intercooler 6 in the intake passage 3.

[0013] A catalyst 7a for purifying exhaust gas and a filter 7b for collecting exhaust particulates are provided downstream of the turbine 5a in the exhaust passage 4. The filter 7b is provided downstream of the catalyst 7a. The catalyst 7a contains catalytic metals such as platinum (Pt), palladium (Pd) and rhodium (Rh), has oxygen storage capacity, and purifies NOx, HC and CO. The filter 7b is a porous ceramic structure.

[0014] The ECU 30 includes a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). The ECU 30 controls the engine 1 based on information from sensors and information previously stored in the ROM in accordance with a control program previously stored in the ROM. The ECU 30 is an example of a control device for a turbocharged engine.

[0015] The ECU 30 controls the operating state of the engine 1 based on detection signals from various sensors, such as a crank angle sensor 11, an air flow meter 12, and an air-fuel ratio sensor 13. The crank angle sensor 11 detects the rotation angle of the crankshaft of the engine 1. The air flow meter 12 detects the amount of intake air taken into the intake passage 3. The air-fuel ratio sensor 13 detects the air-fuel ratio of the exhaust gas discharged from the engine 1. The accelerator opening sensor 14 detects the accelerator opening, which is the amount of operation of the accelerator pedal.

[0016] The ECU 30 grasps the rotation speed and load of the engine 1 based on output signals from various sensors. The ECU 30 outputs command signals to various drive circuits connected to output ports according to the operating state grasped in this way. The controls performed by the ECU 30 in this way include throttle control for adjusting the opening of the throttle valve 3a, fuel injection control for adjusting the injection amount of the fuel injection valve 2a, and ignition timing control for adjusting the ignition timing of the spark plug 2b.

[0017] [Torque down control and exhaust noise control] When the accelerator opening sensor 14 detects a change from accelerator on to accelerator off, the ECU 30 executes torque down control and also executes exhaust sound control. Fig. 2 is a timing chart showing an example of the torque down control and exhaust sound control executed by the ECU 30. Fig. 2 shows the transition of the accelerator opening, intake air amount, fuel cut flag, fuel injection amount, air-fuel ratio, ignition timing, exhaust sound control flag, and the opening of the wastegate valve 9.

[0018] When the accelerator opening decreases at time t1 and becomes zero at time t2, the ECU 30 executes the torque-down control. In the torque-down control, the intake air amount and the fuel injection amount are gradually decreased, and the ignition timing is temporarily advanced and then gradually retarded. The intake air amount is reduced to the intake air amount during idling. This reduces the torque of the engine 1. Even when the torque-down control is executed, the wastegate valve 9 is maintained in a fully closed state, and the rotation speeds of the turbine 5a and the compressor 5b are maintained high. This ensures high responsiveness to an acceleration request after the execution of the torque-down control. In the torque-down control, the throttle valve 3a is controlled so that the intake air amount is gradually reduced regardless of the opening of the accelerator pedal 18.

[0019] At time t3, a predetermined time after the torque down control is executed, the ECU 30 executes exhaust noise control. In the exhaust noise control, the fuel injection amount is further reduced, the ignition timing is significantly retarded, and the wastegate valve 9 is opened. In the exhaust noise control, the ignition timing is significantly retarded to after the top dead center between the compression stroke and the expansion stroke. This ignition timing is set to, for example, 20° ATDC (After Top Dead Center). By significantly retarding the ignition timing in this manner, the combustion of the air-fuel mixture can be continued until the exhaust valve of the engine 1 starts to open. This increases the exhaust noise, ensuring a good sporty sound.

[0020] As described above, the wastegate valve 9 is opened during exhaust sound control. This ensures a larger flow rate of exhaust bypassing the turbine 5a than when the wastegate valve 9 is closed. As a result, the attenuation of the exhaust sound caused by the turbine 5a is suppressed, ensuring a good sporty sound. In this way, a good sporty sound can be obtained in a vehicle equipped with a turbocharged engine 1. From the viewpoint of suppressing the attenuation of the exhaust sound, it is preferable that the wastegate valve 9 is fully open.

[0021] At time t4, a predetermined time after the exhaust noise control is started, the exhaust noise control is stopped, fuel injection is stopped, and the original fuel cut is executed. If the engine 1 speed falls below the return speed during the fuel cut, the ECU 30 restarts fuel injection by the fuel injection valve 2a.

[0022] The opening of the throttle valve 3a during exhaust noise control may be controlled to be the same as the opening during idle operation, or may be controlled to be slightly more open than the opening during idle operation, or may be controlled to be slightly more closed. The fuel injection amount during exhaust noise control may be controlled to be the same as the injection amount during idle operation, or may be slightly more or slightly less than the injection amount during idle operation.

[0023] In the above embodiment, the ignition timing for exhaust sound control is set to 20° ATDC, but this is not limited to this, and as long as combustion of the mixture continues when the exhaust valve is open, the ignition timing may be, for example, between 17° and 23° ATDC, or between 15° and 25° ATDC.

[0024] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0025] 1 Engine 2a Fuel injector 2b Spark plug 3a Throttle valve 4 Exhaust passage 5. Turbocharger 5a Turbine 8 Bypass Passage 9 Wastegate valve 14 Accelerator opening sensor 30 ECU (supercharged engine control unit)

Claims

[Claim 1] A control device for a turbocharged engine, which controls an ignition timing, a fuel injection amount, and an intake air amount of the turbocharged engine mounted on a vehicle, and also controls a wastegate valve provided in a bypass passage that bypasses a turbine of the turbocharger, A control device for a turbocharged engine that, when transitioning from accelerator on to accelerator off, executes torque down control which retards ignition timing by reducing the fuel injection amount and the intake air amount while closing the wastegate valve, and then executes exhaust noise control which further retards the ignition timing to after top dead center between the compression stroke and the expansion stroke and opens the wastegate valve.

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