JPS62162726A - Supercharge pressure control device for internal-combustion engine with turbocharger - Google Patents

Abstract

PURPOSE:To make building up of torque sharp and to improve acceleration responsiveness, by introducing the atmospheric pressure into a pressure chamber of an equipment for actuating a bypass control valve of a turbocharger through a directional control valve when a rapid acceleration is effected. CONSTITUTION:A bypass passage 24 for bypassing a turbocharger 22 disposed in an intake air passage is provided with a bypass control valve 38. A pressure chamber 44 of an actuator for actuating the control valve 38 is connected with a signal port 62 and an atmospheric pressure port 58 downstream of a throttle valve 18 through an electromagnetic directional control valve 50. A control unit 34 is supplied with an opening degree of the throttle valve 18 and switches the directional control valve 50 at a rapid acceleration wherein a change of a valve opening speed is greater than a prescribed value so that the pressure chamber 44 communicates with the atmospheric pressure port 58. With such an arrangement, since the bypass control valve is closed rapidly, building up of torque is made sharp, whereby acceleration responsiveness is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling the boost pressure of a supercharged internal combustion engine.

[Related technologies and problems]

The present invention is based on a patent application filed on May 27, 1985.
This invention relates to an improvement of the boost pressure control device proposed in No. 2033. For example, FIG. 2 of the above-mentioned patent application shows an engine equipped with a supercharger, and the intake system is provided with a bypass of the supercharger. If you close this bypass while the supercharger is operating, the engine will be supercharged, and if you open the bypass, supercharged air will escape through the bypass to the suction side of the supercharger, stopping supercharging. There is. The bypass is opened and closed by a pressure-responsive bypass control valve. '[The intake pipe pressure obtained from the signal boat downstream of the throttle valve is used for the operating pressure of the D valve. Bypass system? An electromagnetic switching valve is provided in the pressure chamber and signal port of the TIl valve, so that the operating pressure can be switched depending on the acceleration state. That is, during slow acceleration, the intake pipe pressure is applied to the pressure chamber of the bypass control valve through a passage with a restriction, and the bypass control valve gradually closes and supercharging starts slowly, but during sudden acceleration, the intake pipe pressure Since is applied to the pressure chamber through an unrestricted passage, the bypass control valve is quickly closed and supercharging is immediately started.

However, the intake pipe pressure does not respond quickly enough to changes in the throttle valve opening (even if the throttle valve is suddenly opened during rapid acceleration, there is a slight response delay in the change in intake pipe pressure). Therefore, in the system disclosed in the patent application, there is a problem in that during sudden acceleration, there is a delay in closing the bypass control valve due to the delay in response of the intake pipe pressure, resulting in a delay in the rise of torque.

[Purpose of the invention]

The object of the present invention is to further improve the above-mentioned boost pressure control device and to improve the torque rise during sudden acceleration.

[Means and effects for solving the problem] Supercharging pressure control of the present invention:? The tl device includes (a) a pressure-responsive bypass control valve that has a pressure chamber and closes the bypass in response to an increase in pressure within the pressure chamber; (a) an atmospheric pressure boat for taking in atmospheric pressure; and (ii) a signal boat installed in the intake system to take out atmospheric pressure. An electromagnetic switching valve that can now apply pressure to the pressure chamber and (,t) i detect an increase in load, and when the load suddenly increases, atmospheric pressure is applied to the bypass control valve pressure chamber, and when the load gradually increases, atmospheric pressure is applied to the pressure chamber. Intake pipe pressure is applied to the pressure chamber (control means for controlling the electromagnetic switching valve).

In this way, by providing an atmospheric pressure boat, atmospheric pressure is immediately applied to the pressure chamber of the bypass control valve when the load suddenly increases (when the vehicle suddenly accelerates), so the bypass control valve closes more quickly. turbocharging starts earlier, improving acceleration response.

〔Example〕

Referring to FIG. 1, the intake system of an engine 10 includes an air cleaner 12, an intake passage 14, an air flow meter 16, a throttle valve 18, etc., and the fuel supply system includes an electronically controlled fuel injection valve 20.

The intake passage construction 4 is provided with a supercharger 22 and a bypass 24 consisting of a Roots blower. The supercharger 22 is driven by the engine 10 via an electromagnetic clutch 26.
A transmission belt 30 is connected to the input brake 28 of the electromagnetic clutch 26.
Power is transmitted from the crank pulley 32 via. If the electromagnetic clutch 26 is connected while the engine is running, the supercharger 2
2 pressure-feeds intake air, but before the bypass 24 closes, supercharging air escapes to the suction side of the supercharger 22 via the bypass 24, so the engine is not supercharged. The electromagnetic clutch 26 is controlled on/off by an engine control computer (ECU) 34 consisting of a microcomputer. The throttle valve 18 is linked to a throttle sensor 36 that detects throttle opening, and its analog output is sent to the ECU 34.
is input. The output signal of the air flow meter 16 is also EC
Sent to U34.

Bypass 24 is opened and closed by bypass control valve 38.

This control valve 38 has a movable valve body 4 that opens and closes the bypass 24.
0, a diaphragm 42 interlocking with the valve body 40, a pressure chamber 44 and an atmospheric pressure chamber 4 separated by this diaphragm 42;
6, and a return spring 48. The pressure chamber 44 is connected to an outlet port 52 of an electromagnetic switching valve 50. The switching valve 50 has two inlet ports 1-54, 56, and either of these inlet ports can be selectively connected to the outlet port 52. When the switching valve 50 is powered up by the E C [J 34, the second port 56 is connected to the outlet port 52, and when the power is stopped, the first input port 54 is connected to the outlet port 52.

An atmospheric pressure boat 58 is provided in the intake passage 14 upstream of the throttle valve 18 , and this atmospheric pressure boat 58 is connected to a second artificial boat 56 of the switching valve 50 by a pipe 60 . Additionally, a throttle valve 18 is provided in the intake passage 14.
A signal boat 62 is provided downstream of the intake pipe to take out the intake pipe pressure. As is well known, the intake pipe pressure in the signal boat 62 becomes negative pressure when the opening degree of the throttle valve 18 is small, and approaches atmospheric pressure as the throttle opening degree increases. This signal boat 62 is connected to the first input boat 54 of the switching valve 50 by a conduit 64.

According to the above configuration, when the electromagnetic switching valve 50 is energized, the atmospheric pressure of the atmospheric pressure boat 58 is applied to the pressure chamber 44 of the bypass control valve 38, and the control valve 38 is closed. When the power supply is stopped, the intake pipe pressure of the signal boat 62 is applied to the pressure chamber 44, but in this case, the intake pipe pressure changes according to the throttle opening as described above, so when the throttle opening is small and the load is light, Negative pressure is applied to the pressure chamber 44, the bypass control valve 38 is opened, and the bypass 24 is released.Atmospheric pressure is applied to the pressure chamber 44 and the bypass control valve 38 is closed when the throttle opening is large and the load is high. Close bypass 24.

In the case where the first inlet port 54 of the switching valve 50 is connected to the outlet port 52, when the throttle opening degree gradually increases as the load gradually increases, the bypass control? ■Valve 38
It will be understood that the supercharging pressure will rise slowly because the is gradually closed. However, when the throttle opening rapidly increases with a sudden increase in load, there is a response delay in the change in intake pipe pressure, and the intake pipe pressure does not immediately rise from negative pressure to atmospheric pressure. Therefore, when the switching valve 50 is de-energized and the first artificial boat 54 is connected to the outlet port 52, the bypass control iTi valve 38 does not close immediately even if the load suddenly increases, and the boost pressure increases. is delayed, and the required torque rise cannot be obtained. In such a case, the present invention immediately applies the atmospheric pressure of the atmospheric pressure boat 58 to the pressure chamber 44 by applying a 1ffi voltage to the switching valve 50, and immediately closes the bypass control valve 38 to increase the supercharging pressure and increase the torque. The aim is to speed up the start-up. Therefore, ECtJ34 is programmed to perform such control.

ECU 34 is a conventional microcomputer, and its configuration does not require explanation. The ECU 34 controls the electromagnetic switching valve 50 by executing the control routine shown in the flowchart of FIG. 2, thereby controlling the boost pressure. The ECU 34 is primarily intended to control fuel injection amount, ignition timing, etc., and is also used to control boost pressure. The boost pressure control routine shown in the flowchart of FIG. 2 can be executed, for example, every 16 milliseconds as an interrupt routine to the main routine.

In the flowchart of FIG. 2, an interrupt is initiated at step 101. Steps 102 and 103 are for determining whether the vehicle is in an acceleration state or a slow acceleration state, and in this embodiment, the engine load is rapidly increasing based on a change in the throttle opening. It is configured to determine whether there is or is in a gradual increase state. Partly, in step 102, a speed change ΔTA of the throttle opening TA is calculated based on the signal from the throttle sensor 36. The speed change ΔTA can be determined, for example, by calculating the difference between the throttle opening TA during the previous routine execution and the throttle opening TA during the current routine execution.

Next, in step 103, it is determined whether the throttle opening speed change ΔTA is larger than a set value (for example, 10°/16 milliseconds). If the engine load is large, it is assumed that the engine load is rapidly increasing, that is, the vehicle is rapidly accelerating, the process proceeds to step 104, where the electromagnetic switching valve 50 is energized, and the process returns to the main routine in step 105. As a result, the second port 56 of the switching valve 50 is connected to the outlet boat 52, and the atmospheric pressure of the atmospheric pressure boat 58 is transferred to the bypass control valve 38.
is applied to the pressure chamber 44 so that the control valve 38 closes the bypass 24 and the engine is supercharged.

If the throttle opening speed change ΔTA is smaller than the set value, it is assumed that the load is gradually increasing, that is, the vehicle is in a slow acceleration state, and the process proceeds to step 106 to change the if to the switching valve 50.
Stop f electricity. As a result, the first port 54 is strongly connected to the outlet boat 52, so that the control valve 38 opens and closes in accordance with the intake pipe pressure in the signal boat 62. Therefore, when the load is light, the intake pipe pressure becomes negative pressure, so the bypass control valve 38 is opened to lower the supercharging pressure, and when the load is high, the intake pipe pressure becomes atmospheric pressure, so the control valve 38 closes and supercharging is reduced. It will be done. Furthermore, during slow acceleration, the intake pipe pressure gradually changes from negative pressure to atmospheric pressure, so the supercharging pressure gradually increases and the engine output also increases relatively rapidly.

In the above embodiment, the acceleration state was determined using the speed change of the throttle opening in the determination at step 103, but the engine - The intake air ff1Q/N per rotation may be calculated, and the acceleration state may be determined based on the speed change of this Q/N.

In addition, the first artificial boat 5 of the signal port 62 and the switching valve 50
4 may be provided with a throttle or a check valve with a throttle as illustrated in Japanese Patent Application No. 112033/1982. In this way, the rise in torque during slow acceleration can be made gentler.

〔Effect of the invention〕

The effects specific to the present invention can be easily understood by referring to the graph in FIG. Figure 3 shows a comparison of the characteristics of the device of the present invention and the device of Japanese Patent Application No. 112033/1986, which had a capture chamber, during sudden acceleration, and Figure 3 (a) shows the change in throttle opening. , (ol is the position of the switching valve 5o, ←1) is the pressure change in the pressure chamber 14 of the bypass control valve 38,
indicates torque fluctuation. When sudden acceleration starts at time T, and the throttle opening TA rapidly increases, the device of the present invention
2, the N-magnetic switching valve 50 is excited, and atmospheric pressure is applied to the pressure chamber 44 from the atmospheric pressure boat 5, so the bypass control valve 38 is quickly closed, and the boost pressure and therefore the torque are quickly increased. rise above. On the other hand, as shown by the broken line in Figure 3), in the device of Japanese Patent Application No. 112033/1986, there is a delay in the pressure in the pressure chamber 44 reaching atmospheric pressure due to a delay in the response of the intake pipe pressure. Therefore, since the bypass control valve 38 closes relatively slowly compared to the present invention, the rise of torque tends to be delayed.

As described above, according to the present invention, a sudden rise in torque can be obtained during rapid acceleration, thereby improving the responsiveness of the engine. Moreover, since the bypass control valve 38 is controlled by the intake pipe pressure during slow acceleration, it is possible to prevent a sudden increase in torque due to sudden closing of the bypass.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a supercharged engine equipped with the boost pressure control device of the present invention, FIG. 2 is a flowchart of the boost pressure control routine, and FIG. 3 is a diagram showing the device of the present invention and the above Iz. It is a graph showing the characteristics of the device. 14... Intake 1lTl path, 18... Throttle valve, 22... Supercharger, 24... Bypass, 34... Engine control computer, 36...
・Throttle sensor, 38... Bypass control valve, 44... Pressure chamber, 50... Solenoid switching valve,
52...Exit boat, 54, 56...Entrance boat, 58...Atmospheric pressure boat, 62...Signal port. 22...Supercharger 44...Pressure chamber piece...Switching valve 58...Atmospheric pressure port 62...Signal port Figure 2, Figure 3

Claims (1)

[Claims] 1. A supercharged internal combustion engine comprising a supercharger and a bypass for the supercharger in the intake system, (a) having a pressure chamber, and increasing the pressure in the pressure chamber. (b) A signal port provided in the intake system to take out the intake pipe pressure downstream of the throttle valve; (c) A signal port for taking in atmospheric pressure. atmospheric pressure port and (d)
an electromagnetic switching valve capable of selectively applying intake pipe pressure of the signal port or atmospheric pressure of the atmospheric port to the pressure chamber of the bypass control valve; (e) detecting an increased state of engine load; and control means for controlling the electromagnetic switching valve so that atmospheric pressure is applied to the bypass control valve pressure chamber when the load suddenly increases and intake pipe pressure is applied to the pressure chamber when the load gradually increases. Pressure control device.