JPH0378530A - Supercharge pressure control device - Google Patents

Abstract

PURPOSE:To realize a supercharge pressure control at the time of deceleration and a supercharge pressure control for limiting a maximum car speed by providing a diaphragm type open-close valve in a passage, which bypasses a compressor of a supercharger, and actuating this valve to be opened in the case of a car speed in not less than a predetermined value or in a deceleration condition. CONSTITUTION:An intake bypass passage 6, which bypasses a compressor 3a of a supercharger, is provided in an intake passage 2, and a diaphragm type open-close valve 7 is interposed in this passage 6. This open-close valve 7 is opened and closed in accordance with a pressure difference between upper and lower sides of a diaphragm, and a diaphragm chamber 7c communicates with the atmosphere side and the up and downstream sides of a throttle valve 4 in the intake passage 2 through a negative pressure selector valve 8 and the first and second check valves 9, 10. In the negative pressure selector valve 8, by an ECU16 a selective control is performed so as to open a passage 11 and close a passage 12 for actuating the open-close valve 7 to be opened in the case of a car speed in not less than a predetermined value or aa engine in a deceleration condition. In this way, a turbosurge noise is prevented at the time of deceleration while contriving a maximum car speed control of a vehicle.

Description

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

C. Conventional technology] Conventionally, when the boost pressure exceeds a predetermined value during deceleration, etc., the boost pressure is reduced to prevent the boost pressure from becoming abnormally high.
A device has been disclosed that limits the vehicle speed by reducing the boost pressure when the vehicle speed exceeds a predetermined vehicle speed (for example, Japanese Patent Publication No. 1-2
Publication No. 1139).

[Problem to be solved by the invention]

However, in the above-mentioned device, the supercharging pressure increases to a predetermined value during deceleration or the like. Therefore, there is a problem in that turbo surge noise is generated as the boost pressure increases.

In addition, when realizing boost pressure control during deceleration and boost pressure control to limit the maximum vehicle speed using an inexpensive diaphragm single-chamber air bypass valve (ABV), as shown in Figure 2, In addition, negative pressure switching valves (VSV) are required on the upstream and downstream sides of the throttle valve.

Therefore, there are problems such as high cost, large size of the device, and difficulty in mounting it on a vehicle.

The present invention has been made to solve the above-mentioned problems, and its purpose is to control supercharging pressure during deceleration and limit the maximum vehicle speed using an inexpensive and compact device. An object of the present invention is to provide a boost pressure control device that realizes boost pressure control.

(Means for Solving the Problems) Therefore, the present invention provides a supercharger that is provided in an intake passage that supplies intake air to an engine and supercharges the intake air; an intake bypass passage that supplies air from the upstream side to the downstream side of the supercharger; a diaphragm-type opening/closing valve that opens and closes the intake bypass passage; a vehicle speed detection means that detects vehicle speed; and a deceleration device that detects a deceleration state of the engine. a state detection means; a drive signal output means for outputting a drive signal for opening the diaphragm type on-off valve when the vehicle speed is a predetermined vehicle speed or higher or when the engine is in a deceleration state; and a diaphragm chamber of the diaphragm type on-off valve; a first passage communicating with the atmosphere; a second passage communicating the first passage with the upstream side of the throttle valve; and a third passage communicating the first passage with the downstream side of the throttle valve. provided at the intersection of the first passage and the second passage,
a switching valve that introduces pressure from either the first passage or the second passage into the diaphragm chamber of the diaphragm-type on-off valve in response to a drive signal from the drive means; and a switching valve provided in the first passage. a first check valve that closes when the pressure in the first passage is lower than atmospheric pressure; and a first check valve provided in the third passage, the pressure downstream of the throttle valve being equal to the pressure in the first passage. The gist of the invention is a supercharging pressure control device including a second check valve that closes when the supercharging pressure is higher than the supercharging pressure.

[Effect]

Therefore, under normal operating conditions, the first passage is closed by the switching valve, the pressure in the diaphragm chamber is on the m side above the throttle valve led from the second passage, and the diaphragm on-off valve is closed, so that the pressure is not supplied to the engine. The intake air is overpressurized by the supercharger.

Further, in maximum vehicle speed control, the pressure in the first passage is introduced into the diaphragm chamber by the switching valve.

In addition, the pressure on the downstream side of the throttle valve is boost pressure,
The second check valve is closed. Therefore, atmospheric pressure is introduced into the diaphragm chamber from the first passage through the first check valve, the diaphragm on-off valve is opened, and the intake air bypasses the supercharger through the bypass passage and flows upstream of the throttle valve. Therefore, the supercharging pressure decreases.

Further, in the deceleration state, the pressure in the first passage is introduced into the diaphragm chamber by the switching valve. Further, since the pressure on the downstream side of the throttle valve becomes negative pressure, the first check valve closes. Therefore, the intake negative pressure on the downstream side of the throttle valve is guided from the third opening/closing passage to the diaphragm chamber via the second check valve, the diaphragm opening/closing valve is opened, and the intake air is supercharged through the intake bypass passage. Since the boost pressure is supplied to the upstream side of the throttle valve by bypassing the engine, the boost pressure decreases.

〔Example〕

The present invention will be explained based on an embodiment configured as shown in FIG.

Reference numeral 2 denotes an intake passage, through which intake air from an air cleaner (not shown) and an air flow meter for measuring the amount of intake air is supplied to the engine 1 via a supercharging m3 and a throttle valve 4.

As is well known, the supercharger 3 is installed in the intake passage 2 by rotating a turbine 3b installed in the exhaust passage 5 using exhaust gas, and is connected to the turbine 3b and the connecting shaft 3.
The compressor 3a connected by C is rotated to supercharge the intake air.

Further, the intake passage 2 is provided with an intake bypass passage 6 that bypasses the compressor 3a of the supercharger 3. In this intake bypass passage 6, a diaphragm single-chamber air bypass valve (AB
ABV7 is provided, and this ABV7 is opened and closed to control the boost pressure when the vehicle speed exceeds a predetermined vehicle speed and when the vehicle is decelerating.

In the ABV 7, a force is always exerted by the spring 7a in the direction of closing the diaphragm valve 7b. Then, when the pressure on the opposite side of the diaphragm chamber 7C (pressure on the upstream side of the throttle valve 4 in the intake passage 2) becomes greater than the pressure in the diaphragm chamber 7C, and a pressure difference that exceeds the spring force described above occurs, the ABV7 It operates to open. Therefore, the intake air bypasses the compressor 3a and is supplied from the intake bypass passage 6 to the upstream side of the throttle valve 4, so that the supercharging pressure decreases.

Therefore, the ABV 7 is opened and closed by creating a pressure difference between the upper side and the lower side of the diaphragm chamber. Therefore, the diaphragm chamber 7c of the ABV 7 includes a negative pressure switching valve (VSV) 8 as a switching valve, first and second check valves 9.
10, the intake passage 2 is communicated with the upstream and downstream sides of the throttle valve 4 and with the atmosphere.

That is, the ABV 7 has a first passage 11 that communicates the diaphragm chamber 7c with the atmosphere, and a second passage 12 that communicates the first passage 11 with the upstream side of the throttle valve 4.
and a third passage 13 that communicates the first passage 11 with the downstream side of the throttle valve 4. And VS
V8 is provided at the intersection of the first passage 11 and the second passage 12. When this vsvs receives an on signal from the driving means of the electronic control unit (ECU) 16, which will be described later, it closes the second passage 12, and atmospheric pressure or the pressure on the downstream side of the throttle valve 4 is guided to the diaphragm chamber 7C. do it like this. On the other hand, when an off signal is input from the ECU 16, the atmosphere side of the first passage 11 is closed, and the upstream pressure of the throttle valve 4 is guided to the diaphragm chamber 7C side via the second passage 12. .

Further, a first check valve 9 is provided upstream of vsvs in the first passage 11. This first check valve 9 closes when the pressure in the first passage 11 becomes lower than atmospheric pressure.

Furthermore, a second check valve 9 is provided in the third passage 13. This second check valve 9 is closed when the downstream pressure of the throttle valve 4 becomes greater than the pressure in the first passage 11.

On the other hand, the exhaust passage 5 is provided with an exhaust bypass passage 14 that bypasses the turbine 3b of the supercharger 3. In this exhaust bypass passage 14, there is a waste gate.
A valve (WGV-) 15 is provided. During normal driving, a target boost pressure is set according to the driving state, and the WGV 15 is duty-controlled by an ECU 16, which will be described later, so that the actual boost pressure becomes the target boost pressure.

In addition, the ECU 16 receives detection signals from an intake pressure sensor 19, a vehicle speed sensor 20 as a vehicle speed means, and various sensors (not shown), and determines the amount of fuel injected by the fuel injection valve 18 and the ignition amount by the spark plug 17 according to the operating state of the engine. Calculate and control the timing. Also, depending on the operating state of the engine 1, ■S■8 and WGV15 are controlled to control the boost pressure.

In order to input output signals from various sensors, the ECU 16 has an input port 16a equipped with an A/D converter, a multiplexer, etc., and performs the above-mentioned processing based on the detection signals from each sensor input through this input port 16a. A central processing unit (central processing unit) that performs various controls such as
A read-only memory (RO) stores data such as control programs and maps necessary for the CPU 16b to execute the various controls described above.
M) 16c, a random access memory (RAM) 16d in which data necessary for control is temporarily read and written, and an output port 16e as a drive signal output means for outputting drive signals are connected to each of the above parts, and the data It is composed of a pass line 16f serving as a passage, and a power supply unit 16g serving as a power supply circuit that supplies power to each of the above-mentioned parts.

The opening/closing operation of the ABV 7 in response to the on/off signal input from the ECU 16 to the VSV 8 will be described below.

First, in the normal operating state, from the ECU 16 to the VSV8
Off signal is input. Therefore, as described above, S8 opens the second passage 12 and closes the first passage 11, so that the pressure on the upstream side of the throttle valve 4, that is, the supercharging pressure, is in the diaphragm chamber 7c of the ABV7. Further, the pressure on the opposite side of the diaphragm chamber 7c of the ABV 7 is the supercharging pressure. Therefore, the ABV 7 is operated to close by the spring 7a.

Next, when the actual vehicle speed ■ becomes equal to or higher than the predetermined vehicle speed Vmax,
A VSV8 heon signal is input from the ECU 16. Thus, vsvs opens the first passage and closes the second passage 12 as described above. Here, in the second check valve 10, since the pressure on the downstream side of the throttle valve 4 is the supercharging pressure, the second check valve IO is closed. Therefore, A
Atmospheric pressure is introduced into the diaphragm chamber 7C of the BV7 via the first check valve 9. Further, at this time, the pressure on the opposite side of the diaphragm chamber 7c of ABV7 is the supercharging pressure.

Therefore, ABV7 operates to open.

Further, in the deceleration state, the ECU 16 inputs the ■S■8 heon signal. Thus, the VSV 8 opens the first passage 11 and closes the second passage 12 as described above. Here, in the second check valve 10, the pressure on the downstream side of the throttle valve 4 becomes negative pressure due to deceleration of the engine, so the second check valve 10 opens. Therefore, the first passage 1
1 becomes a negative pressure, and the '1st check valve 9 is closed. Therefore, the intake pressure is introduced to the diaphragm chamber 7C of the ABV 7 via the second check valve 10. Also, ABV7
The pressure on the opposite side of the diaphragm chamber 7C is the supercharging pressure. Therefore, ABV7 operates to open.

Next, the opening/closing control of the ABV7 executed by the ECU 16 is controlled by the third
This will be explained based on the flowchart shown in the figure.

This process is executed every predetermined time (5m5ec).

First, in step 101, the actual vehicle speed ■ detected by the vehicle speed sensor 20 is compared with a predetermined vehicle speed Vmax (for example, 130 km/h in this embodiment). If the actual vehicle speed (2) is higher than the predetermined vehicle speed Vmax, an on signal is output to vsvs in step 108 to lower the supercharging pressure in order to control the vehicle speed, and the process ends. Also, step 10
1, if the actual vehicle speed V is less than or equal to the predetermined vehicle speed Vmax,
In step 102, which is a deceleration state detection means, it is detected whether or not the vehicle is in a deceleration state. For example, it is determined whether the amount of change ΔP in the intake pressure over a predetermined period of time (for example, 20w5ec in this embodiment) is less than a predetermined value (for example, -50uwHg in this embodiment).

If the amount of change ΔP is less than a predetermined value, it is determined that the vehicle is in a deceleration state, and the process proceeds to step 107. Here, since it takes several seconds to release the supercharging pressure, it is necessary to open the ABV 7 for a predetermined period of time even after the deceleration state ends. Therefore, in step 107, the time required to open the ABV 7 after the end of the deceleration state (
For example, in this example, the value (100m5ec) corresponds to
00015) to the counter cvsv, and step 1
The process proceeds to 08, outputs the vS■8 heon signal, and ends the process.

Further, if the amount of change ΔP is equal to or greater than a predetermined value in step 102, that is, if the vehicle is not in a deceleration state, it is detected in step 103 whether the counter cvsv is 0 or not. Here, if the counter cvsv is O, that is, if the opening operation of ABV7 is performed for a predetermined time after the end of the deceleration state, in step 104, vs
A vs head off signal is output and the process ends.

On the other hand, if the counter cvsv is not O in step 103, then in step 105 the counter CVS■ is decremented by 1 and the process is completed.

With the above control, the ECU 16
A VSV8 off signal is input from the VSV8, and the intake bypass passage 6 is closed by the above-described operation, so that the intake air is supercharged by the supercharger 3.

If the actual vehicle speed V exceeds the predetermined vehicle speed Vmax, the ECU 16
The VSV8 heon signal is manually input from the VSV8, and the intake bypass passage 6 is opened by the above-described operation. Therefore, the intake air is supplied from the intake bypass passage 6 to the upstream side of the throttle valve 4, bypassing the supercharger 3, and the supercharging pressure is reduced. Therefore, the maximum vehicle speed of the vehicle can be limited.

Further, in the deceleration state, an ON signal is inputted from the ECU 16 to the S8 for a predetermined period of time, and the intake bypass passage 6 is opened by the above-described operation. Therefore, the intake air is supplied from the intake bypass passage 6 to the upstream side of the throttle valve 4, bypassing the supercharger 3, and the supercharging pressure is reduced. Therefore, it is possible to prevent turbo surge noise and the like in the deceleration state.

Therefore, ABV7. VSV8 and check valve 9.10
．． An inexpensive and small configuration such as two units makes it possible to limit the maximum vehicle speed and prevent turbo surge noise during deceleration.

Further, in this embodiment, the deceleration state is detected by the rate of change in the intake pressure, but detection by the rate of change in the opening degree of the throttle valve 4 is also applicable to the present invention.

〔Effect of the invention〕

As described above, the diaphragm type on-off valve, the switching valve and the first. An inexpensive and compact configuration including two second on-off valves has the excellent effect of being able to control the maximum vehicle speed of the vehicle and preventing turbo surge noise during deceleration.

3 passage.

Claims (1)

[Claims] Provided in an intake passage that supplies intake air to the engine,
A supercharger for supercharging intake air, an intake bypass passage that bypasses this supercharger and supplies intake air from an upstream side to a downstream side of the supercharger, and a diaphragm that opens and closes this intake bypass passage. a diaphragm type on-off valve; a vehicle speed detection means for detecting vehicle speed; a deceleration state detection means for detecting a deceleration state of the engine; a drive signal output means for outputting a drive signal for opening the valve; a first passage for communicating the diaphragm chamber of the diaphragm type on-off valve with the atmosphere; and a second passage for communicating the first passage with the upstream side of the throttle valve. a passageway, a third passageway that communicates the first passageway with the downstream side of the throttle valve, and a third passageway provided at the intersection of the first passageway and the second passageway,
a switching valve that introduces pressure from either the first passage or the second passage into the diaphragm chamber of the diaphragm-type on-off valve in response to a drive signal from the drive means; and a switching valve provided in the first passage. a first check valve that closes when the pressure in the first passage is lower than atmospheric pressure; and a first check valve provided in the third passage, the pressure downstream of the throttle valve being equal to the pressure in the first passage. A second check valve that closes when the boost pressure is higher.