JPH0745818B2 - Supercharging pressure control device for internal combustion engine with supercharger - Google Patents

Description

The present invention relates to a supercharging pressure control device for an engine including an engine-driven supercharger.

[Related technology and problems]

It is known that a supercharger such as a Roots blower is provided in the intake system, and this supercharger is driven by the power of the engine via an electromagnetic clutch to supercharge the engine (for example, actual development Sho 59-110330). issue). The intake system is provided with a bypass that bypasses the supercharger, and this bypass is opened and closed by a bypass control valve. When the engine load or the rotational speed exceeds a certain value, the electromagnetic clutch is connected and the supercharger operates. When the load increases further, the bypass control valve closes the bypass,
This starts supercharging.

When the external environment is in a condition where vehicle slip is likely to occur, such as when it is raining, snowing, or when the road surface is frozen, it is not preferable that the engine output suddenly changes. The applicant of the present invention first proposed a supercharging pressure control device for completely stopping supercharging at the time of sudden acceleration when the outside air temperature is low in an engine with a supercharger (special feature dated February 15, 1985). Wish 60-26480
issue). However, with this method, there is a problem that the performance of the engine with the supercharger cannot be sufficiently exerted and sufficient torque cannot be obtained.

[Object of the Invention]

An object of the present invention is to provide a supercharging pressure control device capable of sufficiently exerting output performance of an engine with a supercharger while preventing vehicle slip.

[Means and Actions for Solving Problems]

According to the present invention, a vehicle slip occurs when a sudden torque change occurs in the engine, and even if the generated torque itself is high, if the abrupt torque change is suppressed, the slip is prevented without reducing the output. It is based on the finding that it is possible to achieve the above object by the following means.

That is, according to the present invention, in order to achieve the above object, the first
As shown in the figure, a supercharger driven by the engine is arranged in the engine intake passage, the intake passage upstream of the supercharger and the intake passage downstream of the supercharger are connected to each other by bypass, and bypass control is performed in the bypass. In the internal combustion engine with a supercharger, where the valve is placed and the supercharging pressure increases as the bypass control valve closes, an environmental condition determination for determining whether there is an environmental condition in which vehicle slip is likely to occur And when the above-mentioned environmental conditions do not exist when the operating state in which supercharging is to be performed, the bypass control valve is rapidly closed, and when the above-mentioned environmental conditions exist, the bypass control valve is slowly closed. And a bypass control valve control means for controlling the valve.
When the slip is likely to occur, the bypass control valve control means slowly closes the bypass at the start of supercharging, so that the rise of the supercharging pressure and thus the rise of the torque become slow, and the occurrence of slip is prevented. When there is no fear of occurrence of slip, the bypass control valve control means quickly closes the bypass at the start of supercharging, so that the rise of the torque required for rapid acceleration can be obtained. In either case, the engine is supercharged after the bypass is closed, so that sufficient output can be obtained.

〔Example〕

Referring to FIG. 2, the intake system of the engine 10 includes an air cleaner 12, an intake passage 14, an air flow meter 16, and a throttle valve.
It consists of 18, etc. The fuel supply system comprises a fuel injection valve 22 which is electronically controlled by an engine control computer (ECU) 20. ECU20 is a conventional type consisting of a microcomputer, the intake air amount measured by the air flow meter 16,
The fuel injection amount is calculated in a conventional manner based on the throttle valve opening detected by the throttle sensor 24, the engine speed, and other information, and the fuel injection valve 22 is operated according to the required injection amount. The ECU 20 also controls the boost pressure to be described later.
Is done using. Therefore, the output of the outside air temperature sensor 26 for measuring the outside air temperature is input to the ECU 20.

A supercharger 28 and a bypass 30 are provided in the intake passage 14. The supercharger 28 is connected to the engine 10 via an electromagnetic clutch 32.
Is driven by the crank pulley 34, and power is transmitted from the crank pulley 34 to the input pulley 36 of the electromagnetic clutch 32 via the transmission belt 38. Electronic clutch 32 is EC
On / off control is performed by the U20, and the ECU20 is an electromagnetic clutch when the engine load is high, for example, when the throttle opening increases.
32 is connected and supercharger 28 is operated. When the bypass 30 is closed while the supercharger is operating, supercharging of the engine is started.

A bypass control valve 40 is installed in the bypass 30. The bypass control valve 40 includes a spring-biased diaphragm 44 defining a pressure chamber 42, and a valve body linked to the diaphragm 44.
46 and opens and closes the bypass 30 according to the pressure in the pressure chamber 42. As the operating pressure applied to the pressure chamber 42 of the bypass control valve 40, the intake pipe pressure obtained from the signal port 48 provided in the intake passage 14 downstream of the throttle valve 18 is used. As is well known, the intake pipe pressure at the signal port 48 changes according to the opening of the throttle valve 18, and when the throttle opening is small and the load is light, the intake pipe pressure becomes negative, and the throttle opening is high. It approaches atmospheric pressure when loaded.

The signal port 48 and the bypass control valve pressure chamber 42 are connected via a conduit 52 or 54 which is switched by an electromagnetic switching valve 50. The pipe 54 is provided with a throttling device 56 with a check valve, and the other pipe 52 has no throttle. Solenoid valve 50 is EC
On / off control is performed by U20. In the "ON" position, the pipe line 52 and the pressure chamber 42 are connected, and in the "OFF" position, the throttled pipe line 54 is connected to the pressure chamber 42. It is configured.

FIG. 3 shows a flow chart of a supercharging pressure control routine executed by the ECU 20, and this control routine is started at a constant time interval as an interrupt routine of the main routine. In step 101, the outside temperature THA is detected based on the signal from the temperature sensor 26.
In step 102, it is determined whether the outside air temperature THA is larger than a set value (for example, 0 ° C.). If THA> 0 ° C, it is considered that there is no environmental condition where vehicle slip is likely to occur, and the routine proceeds to step 103, where the electromagnetic switching valve 50
Is set to "ON", and if THA ≤ 0 ° C, it is considered that there are environmental conditions where the outside temperature is low and slip is likely to occur, and the solenoid valve 50 is set to "OFF" in step 105, and then in step 104 the main Return to the routine. By executing the steps 101 and 102 by the ECU 20, the environmental condition determining means shown in FIG. 1 is realized. Incidentally, the step 101,
In 102, by comparing the outside air temperature with a set value (for example, 0 ° C), it was judged whether or not there was an environmental condition in which slip was likely to occur. It may be determined that the environmental conditions that are likely to occur are satisfied. It is also possible to use the signal from the raindrop sensor or the rain sensor provided on the windshield, or the signal from the skid detection device.

If the solenoid operated directional control valve 50 is turned “ON” in step 103 (if slippage is unlikely to occur), the signal port
The bypass control valve pressure chamber 42 and the bypass control valve 48 are connected to each other via a pipe line 52 without a restriction. In this state, when the engine load is small and therefore the throttle valve opening is small, the intake pipe pressure at the signal port 48 becomes a negative pressure, and this intake pipe pressure is applied to the pressure chamber 42, so the bypass control valve 40 Opens,
Open bypass 30. Therefore, even if the supercharger 28 operates, the engine is not supercharged. When the opening degree of the throttle valve 18 increases due to the rapid acceleration of the vehicle, the intake pipe pressure at the signal port 48 becomes atmospheric pressure, and this pressure is immediately transmitted to the pressure chamber 42 via the pipe line 52, so the bypass control valve 40 Closes quickly and the boost pressure rises quickly. Therefore, when there is no environmental condition in which slip is likely to occur, a rapid rise of torque can be obtained.

When the electromagnetic switching valve 50 is turned “OFF” in step 105 (when slip is likely to occur), the signal port 48 and the pressure chamber 42 are connected to each other through the conduit 54 with the throttle 56. In this state, the signal port 48
Since the pressure transmission between the pressure chamber 42 and the pressure chamber 42 is delayed, even if the intake pipe pressure of the signal port 48 changes from negative pressure to atmospheric pressure with the increase of the throttle opening during sudden acceleration, the pressure chamber 42 The pressure of gradually changes from negative pressure to atmospheric pressure. Therefore, the bypass control valve 40 is slowly closed, and the rise of the boost pressure is also slow. For this reason, the engine torque does not suddenly increase, and the occurrence of slip is suppressed. However, after a slight delay, when the pressure in the pressure chamber 42 eventually becomes atmospheric pressure, the bypass control valve 40 is gradually closed and the engine is supercharged. Therefore, it is possible to secure the engine output even under the environmental condition where slip is likely to occur.

〔The invention's effect〕

According to the present invention, the supercharging pressure can be gradually increased at the start of supercharging under the environmental conditions where vehicle slip is likely to occur, such as during rainfall, snowfall, or road surface freezing. While preventing slippage, the output performance of the engine with a supercharger can be exhibited.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a supercharging pressure control device of the present invention,
FIG. 2 is a schematic diagram of an engine with a supercharger equipped with the supercharging pressure control device of the present invention, and FIG. 3 is a flowchart of a supercharging pressure control routine. 14 …… Intake passage, 28 …… Supercharger, 30 …… Bypass, 40…
… Bypass control valve, 42 …… Pressure chamber, 48 …… Signal port,
50 …… Solenoid switching valve, 52 …… Pipeline without throttle, 54 …… Pipeline with throttle, 56 …… Throttle device.

Front page continuation (72) Inventor Naohide Izumiya 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) References JP 57-52635 (JP, A) JP 59-206615 (JP, A)

Claims (1)

[Claims] 1. A supercharger driven by an engine is arranged in an engine intake passage, and an intake passage upstream of the supercharger and an intake passage downstream of the supercharger are connected to each other by a bypass and the bypass is provided in the bypass. An environmental condition for determining whether or not there is an environmental condition in which vehicle slip is likely to occur in an internal combustion engine with a supercharger in which a control valve is arranged and the supercharging pressure increases as the bypass control valve is closed. The determining means and the bypass control valve are rapidly closed when the above-mentioned environmental conditions do not exist when the operating state in which supercharging is to be performed, and the bypass control valve is slowly closed when the above-mentioned environmental conditions exist. And a supercharging pressure control device for an internal combustion engine with a supercharger, comprising: