JPH02207154A - Control device for engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent a shift shock by loosening the implementation condition for the output reduction control reducing the engine output at the time of over- supercharging for an automatic transmission vehicle as compared with a manual transmission vehicle. CONSTITUTION:Fuel injection valves 10 and 11 are controlled according to the fuel feed quantity calculated by a control unit 15 based on the operation state in a rotary piston engine provided with the primary and secondary fuel injection valves 10 and 11 on a suction passage 2 on the downstream of the blower 3 of an exhaust turbo-supercharger. When the supercharged pressure detected by a supercharged pressure sensor 29 is the preset value or above (over-supercharged pressure), the fuel cut control is performed to reduce the engine output. In this case, the implementation condition for the fuel cut control is loosened for an automatic transmission vehicle as compared with a manual transmission vehicle, and the shift shock of the automatic transmission vehicle is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a control device for a supercharged engine.

(Prior art) In a supercharged engine, if the supercharging pressure is too high, problems will arise in the durability of the engine, so it is necessary to control the supercharging pressure so that it does not exceed a predetermined value. be.

As such control, for example, Japanese Patent Application Laid-Open No. 57-122
As disclosed in Publication No. 142, detecting the supercharging pressure of an internal combustion engine equipped with a supercharger driven by exhaust gas,
It is known that when this supercharging pressure exceeds a predetermined pressure, the engine is operated by reducing the number of combustions of the engine, that is, the engine output is reduced during supercharging.

The same control for such a supercharged engine is applied regardless of whether it is a conventional manual transmission vehicle or an automatic transmission vehicle.In other words, in the above control of a conventional supercharged engine, Generally, the predetermined pressure, which is the determination pressure for control, is the same for manual transmission vehicles and automatic transmission vehicles.

(Problem to be Solved by the Invention) In an automatic transmission vehicle, for example, when a gear shift is performed to a high speed gear while accelerating by stepping on the accelerator pedal, the engine speed may temporarily decrease. The intake capacity on the engine side decreases. However, due to the inertial rotation of the supercharger, the supercharging state may remain the same as before, and therefore, during a gear shift, the supercharging pressure may be temporarily increased and exceed the above-mentioned predetermined pressure. be. In such a case, if the engine output is reduced, there is a problem in that a shock occurs due to the reduction in the output during gear shifting.

Note that this problem is unique to automatic transmission vehicles.

On the other hand, if the predetermined pressure is increased in order to prevent shift shock in the automatic transmission vehicle, there is a risk that the overcharging state will continue in the manual transmission vehicle, which will reduce the durability of the engine. Problems arise.

Therefore, the present invention provides an automatic transmission vehicle with a supercharger that can prevent the above-mentioned shift shock during gear shifting, and a manual transmission vehicle with a supercharger that can prevent engine damage due to overcharging. Its purpose is to provide an engine control device.

(Means for Solving the Problems) The present invention provides a control device for a supercharged engine that reduces engine output at the time of boost pressure, in which the conditions for executing the output reduction control are set for a manual transmission vehicle. It is characterized by a ♂ that has been made to be more relaxed than automatic transmission cars.

(Operations and Effects of the Invention) In the supercharged engine control device of the present invention, the conditions for executing output reduction control are relaxed for automatic transmission vehicles as compared to manual transmission vehicles. In a transmission vehicle, it is possible to prevent the above-mentioned shock due to a decrease in engine output during gear shifting, and in a manual transmission vehicle, engine damage due to supercharging can be prevented as in the conventional case.

(Embodiment) Hereinafter, a control device for a supercharged engine according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a control device for a supercharged engine according to an embodiment of the present invention. In this figure, reference numeral 1 indicates a blower 3 interposed in an intake passage v82 and an exhaust passage 4 interposed therein. 1 shows a rotary piston engine which is a supercharged engine configured to pressurize and supply suction through a turbine 5 installed therein. An air cleaner 6 and an air flow meter 7 are provided on the upstream side of the blower 3 in the intake passage 2, and an intercooler 8, a throttle valve 9, and primary and secondary fuel injection valves 10 and 11 are provided on the downstream side. There is. The fuel injection valve 10.11 is communicated with the fuel tank 12 via a fuel passage 13, and is supplied with fuel in the fuel tank 12 by a fuel pump 14. Further, a control unit 15 consisting of a microcomputer is connected to the fuel injection valve 10.11.
5 receives the output signal from the air 70-meter 7,
Based on this signal, a fuel supply amount corresponding to the intake air amount is calculated, and the opening time of the fuel injection valve 10.11 is controlled. The fuel passage 13 is provided with a pulsation prevention damper 16 for preventing pulsation in the fuel supply, and a pressure regulator 17 for adjusting the pressure of the fuel to a predetermined pressure.

The exhaust passage 4 is provided with a bypass passage 20 that bypasses the turbine 5 and relieves exhaust pressure upstream of the turbine 5 downstream of the turbine.

This bypass passage 20 is provided with a waste gate valve 21 for adjusting the passage area of this bypass passage 20, controlling the amount of exhaust gas flowing through the bypass passage, and controlling the supercharging pressure.

This wastegate valve 21 has a normal diaphragm structure, and although not shown, its pressure chamber includes a pressure passage for taking out the intake pressure downstream of the turbine 3 in the intake passage 2, that is, the supercharging pressure. 22 are in communication. One end of the pressure relief passage 23 communicates with the pressure passage 22, and the other end of the pressure relief passage 23 communicates with a portion of the intake passage 2 between the air flow meter 7 and the blower 3. This pressure passage 22 is provided with a duty solenoid valve 24 for opening and closing an intermediate portion thereof. The duty ratio of the operation of the duty solenoid valve 24 is controlled by the control unit 15, and it relieves the boost pressure from the pressure passage 22 according to the duty ratio, and thereby, the diaphragm type wastegate Valve 21
The pressure acting on the pressure chamber is controlled, the opening degree of the waste gate valve 21 is adjusted, and the supercharging pressure is adjusted as described above.

The control unit 15 includes a throttle opening sensor 25, an atmospheric pressure sensor 26, and an engine rotation speed sensor 2.
7. Sensors for detecting the operating state of the engine, such as a vehicle mileage sensor 28 and a boost pressure sensor 29, are connected.

The control unit 15 calculates a target boost pressure according to the output signals related to the engine operating state from the various sensors mentioned above, detects the actual boost pressure with the boost pressure sensor 29, and calculates the actual boost pressure. It also functions to control the pressure to the target supercharging pressure.

The control unit 15 further controls the fuel injection valve 10 when the supercharging pressure is higher than a predetermined value, that is, during supercharging.
．． It also performs control (fuel cut control) to stop fuel injection by 11.

For this reason, the control unit 15 stores in advance a fuel cut control map as shown in FIG. 2, and both of these fuel cut control maps are characteristic lines of boost pressure and engine speed. , a manual transmission vehicle fuel cut control line 11 used for setting a fuel cut determination value, and an automatic transmission vehicle fuel cut control line 'a12.

As can be seen from the figure, the fuel cut control line 12 for automatic transmission vehicles is set to a higher pressure side than the fuel cut control line 11 for manual transmission vehicles, and in automatic transmission vehicles, the fuel cut control line 12 is set to a higher pressure side than the fuel cut control line 11 for manual transmission vehicles. is being eased. A switch 30 that outputs an A/T signal is connected to the control unit 15 when the vehicle equipped with the supercharged engine 1 is an automatic transmission vehicle.

Next, with reference to the flowchart in FIG. 3, fuel cut control performed by the control unit 15 during supercharging pressure will be described.

In this control, first, in step S1, it is determined whether the vehicle is an automatic transmission vehicle by determining whether an A/T signal is output from the switch 30. When this determination is YES, the fuel cut control line β1 for automatic transmission vehicles is read out in step S2, while when the determination is NO, the fuel cut control line β1 for manual transmission vehicles is read out in step S3. Next, in step S4, the read control line 1
2 or fl, the supercharging pressure detected by the supercharging pressure sensor 29 at that time is checked, and it is determined whether the supercharging pressure is larger than the fuel cut determination value. If this determination is YES, the fuel cut is controlled in step S5. If the determination is NO, the control is terminated.

In the above fuel cut control, as described above,
The fuel cut judgment value for automatic transmission vehicles is set higher than that for manual transmission vehicles. For this reason, in automatic transmission vehicles, the supercharging pressure may be temporarily increased as shown by the imaginary line when shifting, but even in this case, the supercharging pressure is shown by the control line 12. Since the fuel cut determination value is not exceeded, there is no possibility that fuel will be cut and engine shock will occur during gear shifting.

In the embodiment described above, the fuel cut judgment value is set to a large value in the case of an automatic transmission vehicle to prevent the occurrence of shock during gear shifting. The fuel may be cut only when the pressure supply state continues for a predetermined period of time. In the case of this control, the same fuel cut determination value is used for both automatic transmission vehicles and manual transmission vehicles, and the value is set by the control line 11 for manual transmission vehicles. . Next, the above control will be explained in detail with reference to FIG.

In this control, first, in step 310, the current supercharging pressure is shown on the control line β1, and it is determined whether the supercharging pressure is greater than the fuel cut determination value. If this determination is NO, the control is immediately terminated. However, if this determination is YES, it is determined in step 311 whether the vehicle is an automatic transmission vehicle. This step 311
When the determination in step SI2 is YES, in step SI2,
Set the timer to time T. This time T needs to be set larger than this time, taking into account the time during which the supercharging pressure increases due to gear shifting. After this, step S
In Step 13, the system waits until the time T has elapsed, and after the time T has elapsed, in Step S14, it is determined again as in Step 310 whether the supercharging pressure is greater than the fuel cut determination value, and when this determination is YES, In step 315, fuel cut control is performed and the control ends.

When the determination in step Sll, that is, the determination that the vehicle is an automatic transmission vehicle, is No, the process directly proceeds to step S15, where fuel cut control is performed and the control is ended.

In the control explained above, the fuel cut is performed only when the supercharging state continues for a predetermined period of time.
When the boost pressure temporarily exceeds the fuel cut judgment value, such as when changing gears in an automatic transmission vehicle, fuel cut is not performed, which prevents shocks when shifting gears. can.

In the above embodiment, the fuel cut was performed as a method of reducing the engine output, but the output may be reduced by controlling the ignition timing.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a boost pressure control device for a supercharged engine according to an embodiment of the present invention, and FIG. 2 is a fuel cut control map used for fuel cut control in the boost pressure control device. FIG. 3 is a flowchart showing an example of fuel cut control, and FIG. 4 is a flowchart showing another example of fuel cut control. ■ Supercharged engine 10.11 Fuel injection valve 15 Control unit 29 Supercharging pressure sensor

Claims (1)

[Claims] In a control device for a supercharged engine that reduces engine output during boost pressure, the conditions for executing the output reduction control are relaxed for automatic transmission vehicles as compared to manual transmission vehicles. A control device for a supercharged engine, characterized by: