JPH086602B2 - Supercharging pressure control device - Google Patents

Description

The present invention relates to a supercharging pressure control device for an engine with a supercharger.

[Conventional technology]

Conventionally, when the supercharging pressure exceeds a predetermined value during deceleration, etc., the supercharging pressure is reduced to prevent the supercharging pressure from becoming abnormally high, and when the vehicle speed exceeds the predetermined vehicle speed, the supercharging pressure is reduced. A device for limiting the vehicle speed is disclosed (for example,
-21139).

[Problems to be Solved by the Invention]

However, in the device as described above, the supercharging pressure rises to a predetermined value during deceleration or the like. Therefore, there is a problem that the turbo surge noise is generated with the increase of the supercharging pressure.

Further, when the supercharging pressure control at the time of deceleration and the supercharging pressure control for limiting the maximum vehicle speed of the vehicle are realized by using an inexpensive diaphragm one-chamber air bypass valve (ABV), as shown in FIG. In addition, a negative pressure switching valve (VSV) is required on the upstream side and the downstream side of the throttle valve, respectively.
Therefore, there are problems that the cost becomes high, the device becomes large, and it is difficult to mount the device on a vehicle.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a boost pressure control during deceleration and a limit for limiting the maximum vehicle speed by an inexpensive and small device. It is an object of the present invention to provide a boost pressure control device that realizes boost pressure control.

[Means for solving the problem]

Therefore, the present invention is directed to a supercharger provided in an intake passage for supplying intake air to an engine for supercharging intake air, and bypassing the supercharger to introduce intake air from the upstream side of the supercharger. An intake bypass passage supplied to the downstream side, a diaphragm type on-off valve for opening and closing the intake bypass passage, a vehicle speed detecting means for detecting a vehicle speed, a deceleration state detecting means for detecting a deceleration state of the engine, and the vehicle speed being a predetermined vehicle speed. In the above case or when the engine is in a decelerating state, drive signal output means for outputting a drive signal for opening the diaphragm-type on-off valve and a first passage for communicating the diaphragm chamber of the diaphragm-type on-off valve with the atmosphere. A second passage that connects the first passage to the throttle valve upstream side; and a second passage that connects the first passage to the throttle valve downstream side. Is provided at an intersection of the first passage and the first passage, and the pressure of either the first passage or the second passage is set in accordance with a drive signal from the drive means. A switching valve that is introduced into the diaphragm chamber of the diaphragm type on-off valve; a first check valve that is provided in the first passage and that closes when the pressure in the first passage is lower than atmospheric pressure; And a second check valve that is provided in the passage and is closed when the pressure on the downstream side of the throttle valve is higher than the pressure in the first passage.

[Action]

Therefore, in the normal operation state, the first passage is closed by the switching valve, the pressure in the diaphragm chamber is the upstream side of the throttle valve introduced from the second passage, and the diaphragm type on-off valve is closed and supplied to the engine. The intake air is overpressurized by the supercharger.

Further, in the maximum vehicle speed control, the pressure in the first passage is introduced into the diaphragm chamber by the switching valve. Further, the pressure on the downstream side of the throttle valve is the supercharging pressure, and the second check valve closes. Therefore, in the diaphragm chamber, the atmospheric pressure is introduced from the first passage through the first check valve, the diaphragm opening / closing valve is opened, and the intake air bypasses the supercharger by the bypass passage to the upstream side of the throttle valve. As it is supplied, the supercharging pressure decreases.

Further, in the decelerated 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 a negative pressure, the first check valve closes. Therefore, the intake negative pressure on the downstream side of the throttle valve is introduced 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 by the intake bypass passage. Since it is bypassed and supplied to the upstream side of the throttle valve, the boost pressure is reduced.

〔Example〕

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

Reference numeral 2 denotes an intake passage, and intake air from an air cleaner (not shown) and an air flow meter for measuring the intake air amount is supplied to the engine 1 via a supercharger 3 and a throttle valve 4.

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

Further, the intake passage 2 is provided with an intake bypass passage 6 that bypasses the compressor 3a of the supercharger 3. Further, in this intake bypass passage 6, a diaphragm single chamber type air bypass valve (AB
V) 7 is provided and this ABV 7 is opened and closed to perform supercharging pressure control when the vehicle speed exceeds a predetermined vehicle speed and when the vehicle is in a decelerating state.

ABV7 has a spring 7a constantly exerting a force in a direction to close diaphragm valve 7b. And the diaphragm chamber 7c
When the pressure on the opposite side of the diaphragm chamber 7c (the pressure on the upstream side of the throttle valve 4 in the intake passage 2) becomes higher than the pressure of (3) and a pressure difference exceeding the above-mentioned spring force is generated, the ABV7 is opened. Therefore, since 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, the supercharging pressure decreases.

Therefore, the opening and closing of the ABV7 is performed by creating a pressure difference between the upper side and the lower side of the diaphragm chamber. Therefore,
The diaphragm chamber 7c of the ABV7 communicates with the atmosphere via the negative pressure switching valve (VSV) 8 as a switching valve and the first and second check valves 9 and 10 on the upstream and downstream sides of the throttle valve 4 of the intake passage 2 and on the downstream side. Has been done.

That is, the ABV 7 has a first passage 11 that communicates the diaphragm chamber 7c with the atmosphere, a second passage 12 that communicates the first passage 11 with the upstream side of the throttle valve 4, and the first passage 11 And a third side communicating with the downstream side of the throttle valve 4.
And the passage 13. And VSV8 is the first passage 11
And the second passage 12 at the intersection. Then, the VSV 8 closes the second passage 12 when an ON signal is input from the driving means of the electronic control unit (ECU) 16 described later, so that the atmospheric pressure or the pressure on the downstream side of the throttle valve 4 is guided to the diaphragm chamber 7c. To On the other hand, when the 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 changed to the diaphragm chamber 7c side to the second side.
To be guided through the passage 12.

Further, a first check valve 9 is provided upstream of VSV8 in the first passage 11. This first check valve 9 is
When the pressure in the passage 11 becomes smaller than the atmospheric pressure, it closes.

Further, a second check valve 9 is provided in the passage 13 shown in FIG. The second check valve 9 closes when the pressure on the downstream side of the throttle valve 4 becomes larger 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. And
A waste gate valve (WGV) 15 is provided in the exhaust bypass passage 14. During normal driving, a target supercharging pressure is set according to the operating state, and the WGV 15 is duty-controlled by the ECU 16 described later so that the actual supercharging pressure becomes the target supercharging pressure.

Further, the ECU 16 receives detection signals from the intake pressure sensor 19, the vehicle speed sensor 20 as a vehicle speed means, and various sensors (not shown), and in accordance with the operating state of the engine, the fuel injection amount by the fuel injection valve 18 and the ignition by the ignition plug 17 Calculate and control the time. Also, depending on the operating state of the engine 1, VS
Control V8 and WGV15 to control boost pressure.

The ECU 16 has an input port 1 equipped with an A / D converter, a multiplexer, etc. for inputting output signals from various sensors.
6a and a central processing unit (CPU) 16b that executes the various controls described above based on the detection signals from the sensors input through the input port 16a.
And a read-only memory (ROM) 16c that stores data such as control programs and maps required to execute the various controls described above by the CPU 16b, and the data required for control temporarily. Read / write random access
A memory (RAM) 16d, an output port 16e as a drive signal output means for outputting a drive signal, and the above-mentioned respective portions are connected to each other, a bus line 16f serving as a data path, and a power supply portion forming a power supply circuit for supplying power to the respective portions It is composed of 16g and.

The opening / closing operation of the ABV7 according to the on / off signal input from the ECU 16 to the VSV8 will be described below.

First, in the normal operation state, the VSV8 off signal is input from the ECU 16. Therefore, since the VSV 8 opens the second passage 12 and closes the first passage 11 as described above, the pressure in the diaphragm chamber 7c of the ABV 7 is on the upstream side of the throttle valve 4, that is, the boost pressure. The pressure on the opposite side of the diaphragm chamber 7c of the ABV7 is the supercharging pressure. Therefore, the ABV 7 is closed by the spring 7a.

Next, when the actual vehicle speed V becomes equal to or higher than the predetermined vehicle speed Vmax, EC
ON signal is input from U16 to VSV8. Therefore, the VSV 8 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 10 is closed. Therefore, the diaphragm chamber of ABV7
Atmospheric pressure is introduced to 7c via the first check valve 9.
At this time, the pressure on the opposite side of the diaphragm chamber 7c of the ABV7 is the boost pressure. Therefore, ABV7 opens.

Further, in the deceleration state, the ON signal is input from the ECU 16 to the VSV8. Therefore, VSV8 is the first passage as described above.
Open 11 and close the second passage 12. Here, in the second check valve 10, the pressure on the downstream side of the throttle valve 4 becomes a negative pressure due to the deceleration of the engine, so the second check valve 10 opens. Therefore, the first passage 11 becomes a negative pressure and the first passage 11
Check valve 9 is closed. Therefore, the intake pressure is introduced into the diaphragm chamber 7c of the ABV 7 via the second check valve 10. The pressure on the opposite side of the diaphragm chamber 7c of the ABV7 is the supercharging pressure. Therefore, ABV7 opens.

Next, the opening / closing control of the ABV7 executed by the ECU 16 will be described based on the flowchart shown in FIG.

This processing is executed every predetermined time (5 msec).

First, in step 101, the actual vehicle speed V detected by the vehicle speed sensor 20 and a predetermined vehicle speed Vmax (for example, 130 km / in this embodiment).
Compare with h). If the actual vehicle speed V is higher than the predetermined vehicle speed Vmax, an ON signal is output to VSV8 in step 108 so as to reduce the supercharging pressure in order to control the vehicle speed, and the processing ends. In step 101, the actual vehicle speed V is the predetermined vehicle speed Vma.
If x or less, the deceleration state detecting means detects whether or not the vehicle is in the deceleration state at step 102. For example, the change ΔP _{m of} the intake pressure for a predetermined time (for example, 20 msec in this embodiment) is determined by Then, determine whether it is less than -50 mmHg). If the change amount ΔP _m is less than the predetermined value, it is determined that the vehicle is in the deceleration state, and the process proceeds to step 107. Since it takes several seconds to release the boost pressure, it is necessary to open the ABV7 for a predetermined time even after the deceleration state ends. Therefore, in step 107, a value (1000/5) corresponding to the time for which the ABV7 is opened after the deceleration state ends (for example, 100 msec in this embodiment) is set in the counter CVSV, and the flow advances to step 108 to output an ON signal to VSV8. The process ends.

Further, when the change amount ΔP _m is equal to or larger than the predetermined value in step 102, that is, when the deceleration state is not established, it is detected in step 103 whether the counter CVSV is 0 or not. Here, when the counter CVSV is 0, that is, when the deceleration state is finished and the ABV7 is opened for a predetermined time, the OFF signal is output to the VSV8 in step 104 and the process is terminated.

On the other hand, when the counter CVSV is not 0 in step 103, the counter CVSV is decremented by 1 in step 105, and the process is terminated.

By the above control, in the normal operation state, the OFF signal is input from the ECU 16 to the VSV 8 and the intake bypass passage 6 is closed by the above-described operation, so the intake air is supercharged by the supercharger 3.

When the actual vehicle speed V exceeds the predetermined vehicle speed Vmax, the ECU 16 outputs VSV
An ON signal is input to 8, and the intake bypass passage 6 is opened by the above operation. Therefore, the intake air bypasses the supercharger 3 from the intake bypass passage 6 and is supplied to the upstream side of the throttle valve 4 to reduce the supercharging pressure. Therefore, the maximum vehicle speed of the vehicle can be limited.

Further, in the deceleration state, the ON signal is input from the ECU 16 to the VSV 8 for a predetermined time, and the intake bypass passage 6 is opened by the above-mentioned operation. Therefore, the intake air bypasses the supercharger 3 from the intake bypass passage 6 and is supplied to the upstream side of the throttle valve 4 to reduce the supercharging pressure. Therefore, it is possible to prevent the turbo surge noise and the like in the decelerated state.

Therefore, the maximum vehicle speed of the vehicle can be limited and the turbo surge noise in the decelerating state can be prevented by the inexpensive and small configuration of the ABV7, VSV8 and the two check valves 9, 10, 2.

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

〔The invention's effect〕

As described above, the maximum vehicle speed control of the vehicle is possible and the turbo surge noise in the decelerating state is prevented by the inexpensive and small configuration including the diaphragm type on-off valve, the switching valve and the first and second on-off valves. It has the excellent effect of being able to.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment to which the present invention is applied, FIG. 2 is a block diagram of an embodiment of the prior art, and FIG. 3 is a flow chart for explaining the operation of the embodiment. 3 …… Supercharger, 6 …… Intake bypass passage, 7 …… Diaphragm type on-off valve, 7c …… Diaphragm chamber, 20 …… Vehicle speed detection means, 16 …… ECU, 8 …… Switching valve, 9 …… No. 1 check valve, 10
...... Second check valve, 11 ...... First passage, 12 ...... Second passage, 13 ...... Third passage.

Claims (1)

[Claims] 1. A supercharger provided in an intake passage for supplying intake air to an engine for supercharging intake air; and a supercharger bypassing the supercharger to introduce intake air from the upstream side of the supercharger. An intake bypass passage supplied to the downstream side, a diaphragm type on-off valve for opening and closing the intake bypass passage, a vehicle speed detecting means for detecting a vehicle speed, a deceleration state detecting means for detecting a deceleration state of the engine, and the vehicle speed being a predetermined vehicle speed. In the above case or when the engine is in a decelerating state, drive signal output means for outputting a drive signal for opening the diaphragm-type on-off valve and a first passage for communicating the diaphragm chamber of the diaphragm-type on-off valve with the atmosphere. A second passage that connects the first passage to the throttle valve upstream side; and a third passage that connects the first passage to the throttle valve downstream side. Provided with the a road first passage to the intersection between the second passage,
A switching valve for introducing the pressure of either the first passage or the second passage into the diaphragm chamber of the diaphragm type on-off valve in accordance with a drive signal from the drive means, and a switching valve provided in the first passage. And a first check valve that closes when the pressure in the first passage is lower than the atmospheric pressure, and the pressure on the downstream side of the throttle valve that is provided in the third passage is the pressure in the first passage. And a second check valve that closes when the pressure is higher.