JPH03253722A - Supercharging pressure control device - Google Patents

Abstract

PURPOSE:To aim at reduction of deceleration shock, extension of the life of a turbocharger, and the like by providing bypass passages which are connected respectively to the upper stream of a throttle valve, the upper stream of the turbocharger, and the inside of an intake manifold, a three-way solenoid valve, and the like. CONSTITUTION:After an intake quantity of air is detected by an air flow sensor 2, the air sucked into an engine is supercharged by a turbocharger 1, and supplied into each cylinder 11 through a throttle valve 7. At the same time, a fuel quantity meeting a detected intake air quantity is calculated by an electron control part 3 so as to be supplied from a fuel injection valve 5 into each cylinder 11. In this case, a three-way solenoid 6 is composed of the passage 8 toward the turbocharger 1 upper stream, the passage 9 toward to the throttle valve 7 upper stream, and a passage 10 for connecting to an intake manifold 12. The three-way manifold 6 is duty-controlled by the electron control part 3 so as to open/close each of passages 8 to 10. It is thus possible to prevent over rich condition and a high load at the time of deceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a boost pressure control device for steady and transient conditions in a turbocharged internal combustion engine.

[Conventional technology]

The conventional device, as described in Japanese Patent Application Laid-Open No. 64-25426, has only a bypass passage connecting the upstream side of the throttle valve and the upstream side of the turbocharger.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration the fact that the air-fuel ratio is controlled by controlling the pressure in the intake manifold, and there is an overrich phenomenon due to insufficient intake air amount during sudden deceleration, and shocks occur. There was a problem with getting bigger.

The present invention aims to prevent over-richness due to insufficient intake air amount during deceleration, and to simultaneously prevent high load on the turbocharger during deceleration by using a three-way solenoid valve.

[Means to solve the problem]

In order to achieve the purpose stated in item 1, a bypass passage is provided that connects the upstream side of the throttle valve, the upstream side of the turbocharger, and the inside of the intake manifold, and a three-way solenoid valve is installed in between, and the duty of the three-way solenoid valve is controlled. It is something.

[Effect]

Thrower 1 - Flow to the upstream of Luchiamba and the turbocharger,
The three-way solenoid valve that connects the inside of the intake manifold controls the duty inside the valve using pneumatic signals obtained from the output of the pressure sensor inside the intake manifold and the output of the throttle angle sensor. The air is swirled upstream of the turbocharger or supplied into the intake manifold.

This makes it possible to control the pressure inside the intake manifold, and at the same time, it also becomes possible to control the pressure between the turbocharger throttle valves.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. An air flow sensor 2 detects the amount of air taken into the engine. It is supercharged by the turbocharger 1 and flows into each cylinder 11 via the throttle valve 7. Also,
The amount of fuel commensurate with the amount of air detected by the air flow sensor 2 is determined by the fuel injection valve 5 according to the result calculated by the electronic control section 3.
is supplied to each cylinder 11 via.

The three-way solenoid 6 includes a passage 8 connecting the upstream side of the turbocharger, a passage 9 connecting the upstream side of the throttle valve 7, and a passage 10 connecting the intake manifold 12. The air upstream of the throttle valve 7 passes through a bypass passage 9 and is divided by a three-way solenoid into air that returns upstream of the turbocharger l and air that flows into the intake manifold air 2 via a bypass 10.

Figure 2 shows the characteristics of a three-way solenoid.

When Duty is small, a lot of water flows to the intake manifold side of flow path (2), and when Duty is set to Dog, a lot of water flows to the turbocharger.

A control method during deceleration using a three-way solenoid will be explained in FIG.

When deceleration is determined based on the amount of change in the throttle valve and the amount of change in the pressure inside the intake manifold, the duty of the three-way solenoid is reduced and air flows into the intake manifold to suppress sudden changes in pressure. can. However, if you continue to supply a large amount of air into the intake manifold, it will cause a feeling of runaway, so gradually
It is necessary to increase y to reduce the supply air in the intake manifold. Furthermore, during deceleration, the pressure upstream of the throttle valve becomes high, increasing the load on the turbo. In order to prevent this, it is necessary to gradually release the pressure upstream of the throttle valve to the upstream side of the turbocharger, and this can be done by increasing the duty of the three-way solenoid. In other words, it is possible to improve the feeling of runaway and protect the turbocharger at the same time.

FIG. 4 shows pressure changes in the intake manifold during deceleration with the throttle valve fully open.

Conventionally, during deceleration, the pressure inside the intake manifold suddenly changed from positive pressure to negative pressure.

Also, at this time, the air-fuel ratio became overrich due to a delay in the response of fuel control, causing a deceleration shock. In the present invention, in order to prevent this air-fuel ratio over-rich, it is possible to efficiently supply supercharged air into the intake manifold, and deceleration shock can be improved.

Further, when the throttle valve is fully closed, the pressure upstream of the throttle valve increases, but the duty control of the three-way solenoid allows the high pressure to escape upstream of the turbocharger, thereby protecting the turbocharger.

〔Effect of the invention〕

According to the present invention, by using a three-way solenoid, it is possible to reduce air-fuel ratio overrich and deceleration shock during deceleration, and to control the pressure between the throttle valve and the turbocharger, thereby shortening the life of the turbocharger due to high load. can be prevented.

[Brief explanation of drawings]

Fig. 1 is an engine system diagram of an embodiment of the present invention;
The figure is a performance diagram of a three-way solenoid, FIG. 3 is a control flowchart using a three-way solenoid, and FIG. 4 is a diagram showing changes in the pressure inside the intake manifold during deceleration in an embodiment of the present invention. 1...turbocharger, 4...pressure sensor, 6...
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Claims (1)

[Claims] 1. In an internal combustion engine with a turbocharger, an intake manifold internal pressure detection device, a bypass passage connecting the throttle valve upstream and the turbocharger upstream, the throttle valve upstream and the inside of the intake manifold, and a three-way solenoid valve interposed therebetween are provided. Features a boost pressure control device.