JP2962108B2 - Turbocharger supercharging pressure controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control device for a turbocharger.

[0002]

2. Description of the Related Art When a load condition or a use condition fluctuates greatly like an automobile engine, it is necessary to appropriately control a supercharging pressure of a turbocharger according to an operation state.

As a conventional supercharging pressure control device for a turbocharger, a bypass valve for bypassing a turbine and discharging a part of exhaust gas, an actuator for driving the bypass valve, and a compressor for supercharging a diaphragm chamber of the actuator. A pressure guiding passage for guiding the pressure, a control valve for varying the throttle for diluting the pressure in the pressure guiding passage, and a control means for adjusting the supercharging pressure in accordance with the operating state. So as not to impair the durability and the like of the engine (Japanese Patent Laid-Open No. 62-276223,
reference).

[0004]

However, in such a conventional turbocharger supercharging pressure control device, when the supercharging pressure suddenly rises when the control valve is opened, the supercharging pressure is increased. When the pressure is led to the diaphragm chamber of the actuator through the pressure guiding passage, the boost pressure is diluted by the control valve and the pressure led to the diaphragm chamber is delayed, so that the bypass valve is opened. Since sufficient responsiveness cannot be obtained, there is a possibility that an overshoot in which the boost pressure becomes higher than the set value may occur.

The present invention has been made in view of the above problems, and has as its object to prevent an overshoot in which the supercharging pressure becomes higher than a set value during rapid acceleration.

[0006]

The present invention is shown in FIG.
As described above, a part of the exhaust gas is discharged by bypassing the turbine 4
Bypass valve 1 and driving this bypass valve 1
Actuator 2 and diaphragm of this actuator 2
Guides the supercharging pressure of the compressor 5 to the ram chamber 3Pressure guiding passage 9
And a condenser for diluting the pressure in the pressure guiding passage 9 through a throttle.
Troll valve 6 and control valve
Control means 7 for opening and closing the lube 6 to adjust the supercharging pressure
In the supercharging pressure control device of the turbocharger 10,
Means 11 for detecting the acceleration of the engine 8;
Means 12 for determining the time of rapid acceleration higher than the value,The supercharging pressure
The control valve 6 is opened by the adjustment control means 7.
The sudden acceleration determination means 12 has determined a rapid acceleration
SometimesControl to temporarily close control valve 6
Means 13.

[0007]

When the control valve 6 is closed, the supercharging pressure of the compressor 5 is directly introduced into the diaphragm chamber 3 through the pressure guiding passage 9 so that the supercharging pressure exceeds the first set value. When it rises, the bypass valve 1 is opened, and the maximum supercharging pressure of the compressor 5 is regulated to a first set value or less.

When the control valve 6 is open, the supercharging pressure introduced into the diaphragm chamber 3 through the pressure guiding passage 9 is diluted via the throttle, so that the supercharging pressure is reduced to the first set value. When the pressure rises above the higher second set value, the bypass valve 1 is opened, and the maximum supercharging pressure of the compressor 5 is restricted to the second set value or less. That is, when the control valve 6 is opened, the maximum boost pressure is increased.

At the time of rapid acceleration when the control valve 6 is opened, by temporarily closing the control valve 6, the supercharging pressure that rises rapidly is guided to the diaphragm chamber 3 through the pressure introducing passage 9. Since the pressure guided to the diaphragm chamber 3 rises quickly without being diluted via the control valve 6 and the responsiveness of the opening operation of the bypass valve 1 is enhanced, the supercharging pressure is set to be lower than the second set value. High overshoot can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, each cylinder 2 of the engine 8
Exhaust gas discharged from 1 is collected in the manifold 22 and introduced into the turbine 4, and then discharged outside through the exhaust pipe 23.

The turbocharger 10 rotates the turbine 4 at high speed by the pressure energy of the exhaust gas,
Drive the compressor 5 connected via the.

The compressor 5 supercharges the air taken in from the intake pipe 25 in accordance with the rotation speed, and supplies the air to each cylinder 21 from the intake pipe 26 through the intake manifold 27.

A bypass port 29 for bypassing the turbine 4 and discharging a part of the exhaust gas is formed, and a bypass valve 1 for opening and closing the bypass port 29 is provided.

An actuator 2 for opening and closing the bypass valve 1 by air pressure is provided. Actuator 2
The diaphragm chamber 3 communicates with the downstream side of the compressor 5 via a pressure guiding passage 9 and a control valve 6.
And, it communicates with the upstream side of the compressor 5 through the throttle 19.

The control valve 6 opens when the excitation current is sent from the control unit 20 and closes when the control unit 20 is not energized.

When the control valve 6 is closed, the supercharging pressure of the compressor 5 is directly introduced into the diaphragm chamber 3 through the pressure guiding passage 9 so that the supercharging pressure becomes equal to the first set value (for example, When the pressure exceeds 350 mmHg, the bypass valve 1 is opened and a part of the exhaust gas is released, so that the maximum supercharging pressure of the compressor 5 is regulated to a first set value or less.

When the control valve 6 is open, the supercharging pressure introduced into the diaphragm chamber 3 through the pressure guiding passage 9 is diluted through the throttle, so that the supercharging pressure is reduced to the first set value. A higher second set value (eg, 450 mmHg)
When the pressure exceeds the maximum value, the bypass valve 1 is opened to release the exhaust gas. Therefore, the maximum supercharging pressure of the compressor 5 is restricted to a second set value or less.

The control unit 20 opens and closes the control valve 6 according to the operating state of the engine 8, and when the engine 8 is not rotating, when the arithmetic unit (CPU) of the control unit 20 is operating as a backup, or when regular gasoline is used. 6 is closed to regulate the maximum supercharging pressure to the first set value. Thus, for example, when using regular gasoline, the occurrence of knocking or the like is avoided by restricting the maximum supercharging pressure to a small value.

By the way, FIG. 4 shows the change characteristic of the supercharging pressure at the time of rapid acceleration, rapid acceleration of the control valve 6 is opened, the boost pressure P _B of the intake pipe 26 is indicated by a solid line in FIG. Causes an overshoot that becomes abnormally high.
This is because the supercharging pressure that rises rapidly during rapid acceleration is guided to the diaphragm chamber 3 of the actuator 2 through the pressure guiding passage 9, and the supercharging pressure is diluted via the control valve 6 to the extent that the supercharging pressure is diluted by the control valve 6. a delay in the rise in pressure in the valve opening operation of the bypass valve 1 supercharging pressure P _B is considered to be increased by late moment.

In order to cope with this, the present invention performs control to temporarily close the control valve 6 at the time of rapid acceleration when the control valve 6 is opened.

As means for detecting the acceleration of the engine 8, a throttle opening sensor 32 for detecting the opening TVO of the throttle valve 31 is provided. The acceleration state can be determined by comparing the time change ΔTVO of the opening TVO of the throttle valve 31 with a reference value. The throttle opening sensor 32 can be constituted by, for example, a potentiometer whose output value increases in accordance with the opening TVO of the throttle valve 31.

As means for detecting the acceleration of the engine 8, it is conceivable to detect a temporal change in the fuel supply amount or a temporal change in the supercharging pressure of the compressor 5.

FIG. 3 is a flowchart showing a program executed by the control unit 20 for controlling the supercharging pressure at the time of sudden acceleration, which is executed at regular intervals or in synchronization with the engine rotation. First, an operation state where the control valve 6 is energized and opened to increase the maximum supercharging pressure to the second set value is determined (steps 1 and 2).
2).

When the control valve 6 is opened, the acceleration state is determined by comparing the time change ΔTVO of the opening TVO of the throttle valve 31 with a reference value (steps 3, 4, 5).

When it is determined that the control valve 6 has been opened and sudden acceleration has occurred, the control valve 6 is temporarily closed.
Is performed by the control unit 20. sand
That is , the control valve 6 is closed, and when a predetermined delay time (for example, 0.4 sec) elapses, the control valve 6 is opened, and this routine ends (steps 5, 6, 7, 8, 9, 10).

By performing control to temporarily close the control valve 6 at the time of rapid acceleration when the control valve 6 is opened in this manner, as shown by a broken line in FIG. supercharging pressure is guided to the diaphragm chamber 3 rises rapidly, the bypass valve 1 is for the response is enhanced to release a part of opened working exhaust gas, the boost pressure P _B in the intake pipe 26 second It is possible to avoid an overshoot that increases beyond the set value.

When high-load operation can be continued after sudden acceleration,
By opening the control valve 6 with the to elapse of a predetermined delay time, supercharging pressure P _B converges to the second set value as indicated by the one-dot chain line in FIG. 4 in the intake pipe 26.

[0029]

As described above, the present invention provides a bypass valve for bypassing a turbine and discharging a part of exhaust gas, and a control valve for diluting a supercharging pressure for driving an actuator of the bypass valve. The control valve opened in the turbocharger boost pressure control device that adjusts the boost pressure according to the engine operating state .
In this state, when the sudden acceleration is determined, the control valve is temporarily closed, so that the pressure guided to the diaphragm chamber is quickly raised, and the responsiveness of the bypass valve being opened is improved. Further, it is possible to prevent an overshoot in which the supercharging pressure becomes higher than the set value.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a mechanical configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a control operation performed by the control unit.

FIG. 4 is a characteristic diagram of the supercharging pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bypass valve 2 Actuator 3 Diaphragm chamber 4 Turbine 5 Compressor 6 Control valve 7 Supercharging pressure control means 8 Engine 9 Pressure guiding passage 10 Turbocharger 11 Engine acceleration detection means 12 Rapid acceleration judgment means 13 Valve closing control means

Claims (1)

(57) [Claims] A bypass valve for bypassing a turbine to discharge a part of exhaust gas, an actuator for driving the bypass valve, a pressure guiding passage for guiding a supercharging pressure of a compressor to a diaphragm chamber of the actuator, In a turbocharger supercharging pressure control device comprising: a control valve for diluting the pressure of a pressure guiding passage through a throttle; and control means for opening and closing the control valve in accordance with an operation state to adjust a supercharging pressure. Means for detecting acceleration, means for determining when the acceleration is suddenly higher than a predetermined value, and control by the supercharging pressure adjustment control means.
While the valve is open, the sudden acceleration determination means
Control means for temporarily closing the control valve when the determination is made .