JPS6349546Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to a boost pressure control device for a supercharged engine, and in particular, during supercharging of a carburetor engine with a supercharger, speed reduction or speed change is performed to reduce the speed of the carburetor. When closing the throttle valve, the exhaust bypass passage that bypasses the exhaust turbine is reliably opened for a certain period of time to avoid unnecessary drive of the turbocharger compressor and prevent excessive boost pressure from building up in the intake passage. The present invention relates to a supercharging pressure control device for a supercharged engine that can prevent the occurrence of runaway of a vehicle and improve engine drivability.

[Technical background of the invention]

In a turbocharged carburetor engine, an exhaust bypass passage is provided in the exhaust passage by bypassing the exhaust turbine, and when the pressure of intake air, which is the boost pressure downstream of the turbocharger, exceeds a predetermined value, the exhaust bypass passage A wastegate system is used in which the exhaust gas is opened to allow some of the exhaust gas to bypass the exhaust turbine, reducing the driving force applied to the supercharger and controlling the boost pressure in the intake passage. In this method, a waste gate valve, which is a bypass passage opening/closing valve that opens and closes the exhaust bypass passage, is installed in the exhaust bypass passage, and this waste gate valve is operated by an actuator to control the boost pressure in the intake passage. be.
The above-mentioned actuator is actuated by the pressure of the intake air which is the supercharging pressure downstream of the compressor of the supercharger.

[Problems with background technology]

By the way, conventionally, when an engine is being supercharged, even if the accelerator pedal is released to decelerate or change gears, the supercharger continues to rotate, and as a result, the supercharging pressure increases against the throttle valve return spring. This caused the engine to continue to operate at a high speed, causing the vehicle to run out of control, which was dangerous. In order to eliminate this inconvenience, the above-mentioned wastegate method was developed.

However, when the intake pressure that opens the wastegate valve decreases, the wastegate valve immediately closes, causing the exhaust to flow to the exhaust turbine, causing the exhaust flow to rotate the exhaust turbine again. As a result, the compressor is driven more than necessary, and the supercharging pressure in the intake passage rises again and becomes excessive, and this increased supercharging pressure presses the carburetor throttle valve to open it again, causing the above-mentioned vehicle There was a risk that the vehicle would run out of control, and drivability was impaired.

[Purpose of invention]

Therefore, the purpose of this invention was to eliminate the above-mentioned disadvantages by installing a carburetor engine in a position downstream of the compressor of the supercharger and not affected by pressure changes due to the open/closed state of the carburetor throttle valve. A pressure guide port is provided in the intake passage upstream of the carburetor throttle valve to introduce the pressure of the intake air to the diaphragm chamber of the actuator. A pressure holding mechanism is provided to reduce the pressure applied to the diaphragm chamber for a certain period of time when the vaporizer throttle valve is closed, and to open the bypass passage opening/closing valve. Immediately acts on the diaphragm chamber, and when the pressure from the pressure port is less than a predetermined value and the pressure in the pressure path drops, the rate of pressure drop is delayed, and the diaphragm is stopped for a certain period of time in cooperation with the pressure holding mechanism. By providing a pressure drop delay mechanism that maintains the pressure acting on the chamber and opens the bypass passage opening/closing valve, when the pressure from the pressure guiding port exceeds a predetermined value, the pressure is immediately applied to the diaphragm chamber to open the exhaust bypass passage. In addition to ensuring that the exhaust bypass passage opens, it also delays the rate of pressure drop in the pressure passage when decelerating or changing gears and closing the carburetor throttle valve during engine supercharging, ensuring that the exhaust bypass passage closes quickly. This prevents the throttle valve from opening due to inconvenient boost pressure and causing the vehicle to run out of control. It also improves engine drivability and ensures the operation of the bypass passage opening/closing valve, greatly increasing reliability. The object of the present invention is to realize a boost pressure control device for a supercharged engine that can be used as a supercharged engine.

[Structure of the idea]

In order to achieve this object, this invention provides an exhaust bypass passage in the exhaust passage that bypasses the supercharger exhaust turbine, and also provides a bypass passage opening/closing valve that opens and closes the exhaust bypass passage. A pressure guiding port of a pressure guiding passage is provided in the middle of the intake passage on the upstream side of the carburetor throttle valve, which is a position downstream of the compressor of the machine and not affected by pressure changes due to the opening/closing state of the carburetor throttle valve. The pressure guiding passage is provided in communication with a diaphragm chamber of an actuator that opens and closes the bypass passage opening/closing valve, and the pressure guiding passage is provided with a pressure holding mechanism and a pressure drop delay mechanism, and the pressure holding mechanism is connected to the pressure guiding passage. is configured to alleviate vibrations in the pressure that is guided by the diaphragm chamber and that acts on the diaphragm chamber, maintains the pressure that acts on the diaphragm chamber for a certain period of time when the carburetor throttle valve is closed, and opens the bypass passage opening/closing valve; The pressure drop delay mechanism causes the pressure to immediately act on the diaphragm chamber when the pressure from the pressure impulse port is equal to or higher than a predetermined value, and when the pressure from the pressure impulse port becomes less than a predetermined value, the pressure in the pressure passage is controlled. When the pressure decreases, the rate of decrease of the pressure is delayed, the pressure acting on the diaphragm chamber is maintained for a certain period of time in cooperation with the pressure holding mechanism, and the bypass passage opening/closing valve is opened. shall be.

[Example of idea]

Embodiments of this invention will be described in detail and specifically below based on the drawings.

The figure shows an embodiment of this invention. In the figure, 2 is an intake passage and 4 is a supercharger. This supercharger 4 includes a compressor 6 and an exhaust turbine 8.
It has Further, 10 is a carburetor, 12 is a throttle valve of this carburetor 10, 14 is an engine part, 16
is the exhaust passage. That is, the compressor 6 of the supercharger 4 is interposed in the middle of the intake passage 2, and the carburetor 10 equipped with a throttle valve 12 is provided in the intake passage 2 downstream of the compressor 6. An engine section 14 is installed in series. Further, an exhaust passage 16 is provided in the engine section 14 with an open starting end, and the exhaust turbine 8 of the supercharger 4 is interposed in the middle of the exhaust passage 16. As a result, the exhaust flow flowing into the exhaust passage 16 from the engine section 14 rotates the exhaust turbine 8, and the rotational force of the exhaust turbine 8 drives the compressor 6 to pressurize the intake air in the intake passage 2. The pressurized supercharged intake air is supplied to a combustion chamber (not shown) of the engine section 14. Further, the exhaust passage 16 is provided with an exhaust bypass passage 18 that bypasses the exhaust turbine 8. That is, the bypass port 20 is opened in the exhaust passage 16 on the side of the engine section 14 from the exhaust turbine 8, and the opening at the end of the exhaust bypass passage 18 is communicated with the downstream side of the exhaust turbine 8. Furthermore, a waste gate valve 22 which is a bypass passage opening/closing valve that opens and closes the bypass port 20 of the exhaust bypass passage 18 is provided.

The throttle valve 12 of the carburetor 10 is located downstream of the compressor 6 of the supercharger 4 and is not affected by pressure changes due to the opening/closing state of the throttle valve 12.
In the middle of the intake passage 2 on the upstream side, which is separated from the main body of the carburetor 10, there is a pressure guiding passage 24.
A pressure guiding port 26 is provided as a starting end opening. Further, the terminal opening of this pressure guiding passage 24 is controlled by an actuator 2 that opens and closes the waste gate valve 22.
It communicates with the diaphragm chamber 30 of No. 8. A diaphragm chamber 30 of this actuator 28 is partitioned by a diaphragm 32 and communicates with the pressure guiding passage 24 . Further, one end of a diaphragm spring 34 is pressed against one side of the diaphragm 32 facing the diaphragm chamber 30,
The other end of this diaphragm spring 34 is pressed against the inner wall of the actuator 28. This diaphragm spring 34 is connected to the diaphragm chamber 3
The diaphragm 32 is provided to urge the diaphragm 32 in the zero contraction direction. Further, one end of a rod 36 is fixed to the center of this diaphragm 32,
The other end of this rod 36 is pivotally connected to a valve link 38. The other end of the valve link 38 is connected to the waste gate valve 22, which is a bypass passage opening/closing valve that opens and closes the bypass port 20, that is, the exhaust bypass passage 18.

Further, a one-way delay valve 40 as a pressure drop delay mechanism and a volume 42 as a pressure holding mechanism are provided in the middle of the pressure guiding passage 24.

The one-way delay valve 40, which is the pressure drop delay mechanism, immediately applies the pressure to the diaphragm chamber 30 when the pressure of the intake air, which is the boost pressure from the pressure guidance port 26, is equal to or higher than a predetermined value. The pressure from the pressure passage 24 becomes less than a predetermined value.
When the pressure of ing.

That is, a one-way delay valve 40 is provided on the pressure-guiding port 26 side of the pressure-guiding passage 24, and a ball 44 is interposed in this one-way delay valve 40.
A spring 46 is compressed in the ball 44.
A diaphragm 48 is formed so as to bypass the section. As a result, when the intake pressure of a predetermined value or more is generated in the intake passage 2, the ball 44 is moved against the biasing force of the spring 46 by the pressure of this intake air, and the pressure is immediately applied to the diaphragm chamber 30. The waste gate valve 22 is then separated from the bypass port 20 to open the bypass port 20.

The volume 42, which is the pressure holding mechanism, alleviates the vibration of the pressure guided by the pressure guiding passage 24 and acts on the diaphragm chamber 30, and also controls the throttle valve 10.
The wastegate valve 22 is configured to maintain the pressure acting on the diaphragm chamber 30 for a certain period of time and open the wastegate valve 22 during the closing operation. That is, the volume 42
is interposed between the actuator 28 of the pressure guiding passage 24 and the one-way delay valve 40. This volume 42 is used when the throttle valve 12 is closed by decelerating or changing gears during engine supercharging.
It maintains the pressure acting on the diaphragm chamber 30 of the actuator 28 and also alleviates minute fluctuations such as pulsations in the pressure of intake air, which is the operating pressure. When the pressure of the intake air, which is the boost pressure in the intake passage 2, becomes less than a predetermined value and the pressure in the pressure guiding passage 24 drops, the ball 44 of the one-way delay valve 40 is returned by the biasing force of the spring 40. The passage is closed, and the one-way delay valve 40 retards the rate of pressure drop using the throttle 48, thereby maintaining the pressure between the diaphragm chamber 30 and the one-way delay valve 40 for a certain period of time.

Therefore, preferably, when setting the throttle 48, when the pressure guiding port 26 is opened to the atmosphere,
It is preferable that the pressure drop rate of the actuator 28 from the pressurized state of 0.4 Kg/cm ² or more is set to be 0.1 Kg/cm ² /second or more.

Since this embodiment is configured as described above,
It works as follows:

When the engine rotates at high speed, the compressor 6 is driven at high speed, and the supercharging pressure in the intake passage 2 increases.
This boost pressure passes through the pressure guidance port 26 and into the pressure guidance passage 24.
The operating pressure is introduced into the This pressure passage 2
When the pressure within the spring 4 exceeds a predetermined value, this pressure causes the ball 44 of the one-way delay valve 40 to
As a result, pressure immediately acts on the diaphragm chamber 30 through the volume 42, and the diaphragm 32 is pushed against the urging force of the diaphragm spring 34 in the direction of the rod 36. The actuation of the diaphragm 32 causes the rod 36 to move, rotating the valve link 38 pivotally attached to the tip of the rod 36, thereby opening the waist gate valve 22 away from the bypass port 20. Then, the exhaust flow flows away through the exhaust bypass passage 18, the drive of the supercharger 4 is suppressed, and the supercharging pressure is controlled. At this time, the pressure inside the pressure passage 24 fluctuates slightly, but since this pressure fluctuation is alleviated by the regulator 42, this slight pressure fluctuation is
This has no effect on the opening/closing operation of the valve 2, and therefore no supercharging artery occurs.

Further, when the throttle valve 12 is closed by decelerating or changing the speed of the vehicle from a supercharging state that is a high-load running state, the volume 42 is controlled by the actuator 28.
The pressure acting on the diaphragm chamber 30 is maintained. At this time, when the supercharging pressure in the intake passage 2 becomes less than a predetermined value and the pressure in the pressure guiding passage 24 drops, the ball 44 of the one-way delay valve 40 returns due to the biasing force of the spring 46 and closes the passage. accomplished,
Then, the one-way delay valve 40 delays the rate of pressure drop using the throttle 48, and during this time, the positive pressure is maintained between the diaphragm chamber 30 and the one-way delay valve 40 in cooperation with the volume 42 for a certain period of time. . As a result, most of the exhaust gas that tries to rotate the exhaust turbine 8 is transferred to the exhaust bypass passage 1.
8, the rotation of the exhaust turbine 8 is suppressed, that is, the drive of the supercharger 4 is suppressed, and the throttle valve 12 in the intake system is smoothly closed, reducing the amount of intake air. By both of these, the supercharging pressure in the intake passage 2 is efficiently lowered, and the throttle valve 1
2 can be closed by the return urging force of a throttle valve spring (not shown). That is, in this embodiment, since the volume 42 as a pressure holding mechanism and the one-way delay valve 40 as a pressure drop delay mechanism are provided in the middle of the pressure guiding passage 24, the diaphragm chamber 30 of the actuator 28 has a corresponding The pressure continues to act for a certain period of time, and the waste gate valve 22 continues to be reliably released for a certain period of time when the throttle valve 12 is closed. As a result, the rotation of the supercharger 4 gradually decreases, preventing the inconvenience of starting resupercharging as in the conventional case, and preventing the throttle valve 12 from opening due to inconvenient supercharging pressure and causing the vehicle to run out of control.
It also improves engine drivability.

In addition, the pressure guiding port 26 of the pressure guiding passage 24 is located downstream of the compressor 6 of the supercharger 4 and is spaced apart from the main body of the carburetor 10, which is a position that is not affected by pressure changes due to the opening and closing states of the throttle valve 12. By providing the waste gate valve 22 in the middle of the intake passage 2 on the upstream side, the supercharging pressure is temporarily increased at the beginning of engine deceleration or during gear shifting, increasing the operation of the actuator 28, thereby opening and closing the bypass port 20. The operation of the actuator 28 can be ensured and reliability can be increased, and the pressure inside the pressure passage 24 can be prevented from changing unnecessarily due to the opening/closing operation of the throttle valve 12. It is possible to properly ensure that the waste gate valve 22 opens and closes accurately, and improves the reliability of boost pressure control. Furthermore, when the throttle valve 12 is closed, the pressure in the intake passage 2 between the compressor 6 and the throttle valve 12 increases rapidly, so even when the engine section 14 is coasting, pressure remains in the pressure guiding passage 24. (positive pressure) is applied to actuate the actuator 28, and the actuator 28 moves the waste gate valve 22 away from the bypass port 20, causing exhaust gas to flow out of the exhaust bypass passage 18 and By suppressing the drive and preventing the compressor 6 from being driven in vain, it is possible to reliably prevent the vehicle from running out of control.

Note that this invention is not limited to the above-mentioned embodiments,
Of course, various applications and modifications are possible.

For example, in the above-described embodiment, the volume 42 for alleviating minute pressure fluctuations and maintaining the pressure was provided in the middle of the pressure guiding path 24 between the diaphragm chamber 30 of the actuator 28 and the one-way delay valve 40. 42 can also be configured integrally with the diaphragm chamber 30. In addition, the pressure guiding path 2
4 itself can be expanded to function as a volume, and the same effect can be obtained.

[Effect of idea]

As is clear from the above detailed explanation, according to this invention, the intake air is located downstream of the compressor of the supercharger and upstream of the throttle valve, which is a position that is not affected by pressure changes due to the open/closed state of the carburetor throttle valve. In the middle of the passage, there is a pressure guidance port for guiding the intake pressure to the actuator, which alleviates the vibration of the pressure that is guided by the pressure passage and acts on the diaphragm chamber of the actuator, and also when the carburetor throttle valve closes. A pressure holding mechanism is provided that maintains the pressure acting on the diaphragm chamber for a certain period of time and opens the bypass passage opening/closing valve, and when the pressure from the pressure guidance port is equal to or higher than a predetermined value, the pressure is immediately applied to the diaphragm chamber and the pressure is applied to the diaphragm chamber. When the pressure from the diaphragm chamber drops below a predetermined value and the pressure in the pressure guiding passage decreases, the pressure acting on the diaphragm chamber is maintained for a certain period of time by delaying the rate of drop in the pressure and maintaining the pressure acting on the diaphragm chamber for a certain period of time. By providing a pressure drop delay mechanism that opens the on-off valve, when the pressure from the pressure guiding port exceeds a predetermined value, the pressure is immediately applied to the diaphragm chamber to ensure that the exhaust bypass passage is opened and to prevent the engine from overheating. When decelerating or changing gears and closing the carburetor throttle valve during fuel supply, the rate of pressure drop in the pressure passage is delayed to prevent sudden closing of the exhaust bypass passage, which prevents the throttle valve from closing due to unfavorable boost pressure. This prevents the vehicle from running out of control and improves the drivability of the engine.

In addition, the pressure guiding port of the pressure guiding passage is located downstream of the turbocharger compressor and in the middle of the intake passage upstream of the carburetor throttle valve, which is a position that is not affected by pressure changes due to the open/closed state of the carburetor throttle valve. As a result, the boost pressure temporarily increases during the initial deceleration of the engine or during gear shifting, increasing the operation of the actuator, thereby ensuring the operation of the bypass passage opening/closing valve that opens and closes the exhaust bypass passage, thereby increasing reliability. It can be done. In addition, it prevents the pressure in the pressure passage from changing unnecessarily due to the opening and closing operations of the throttle valve, ensures proper operation of the actuator, and ensures accurate opening and closing operations of the wastegate valve. The reliability of pressure control can be improved. Furthermore, when the throttle valve is closed, the pressure in the intake passage between the compressor and the throttle valve increases rapidly.
Even when the engine is coasting, pressure (positive pressure) is applied in the pressure passage to operate the actuator, and the actuator operates to open the wastegate valve, allowing exhaust to flow out from the exhaust bypass passage. This suppresses the drive of the supercharger, prevents the compressor from being driven unnecessarily, and reliably prevents the vehicle from running out of control.

Furthermore, the device according to this invention has a simple configuration,
Maintenance and inspection are easy and the service life can be extended.

[Brief explanation of drawings]

The figure shows an embodiment of this invention, and is a schematic sectional view of a boost pressure control device for a supercharged engine. In the figure, 2 is an intake passage, 4 is a supercharger, 6 is a compressor, 8 is an exhaust turbine, 10 is a carburetor, 12 is a throttle valve, 14 is an engine section, 16 is an exhaust passage, 18 is an exhaust bypass passage, 20 2 is a bypass port, 22 is a wastegate valve which is a bypass passage opening/closing valve, 24 is a pressure passage, 26 is a pressure guidance port, 28 is an actuator, 40 is a one-way delay valve which is a pressure drop delay mechanism, and 42 is a pressure holding mechanism. 44 is a ball, 46 is a spring, and 48 is an aperture.

Claims (1)

[Scope of utility model registration request] An exhaust bypass passage that bypasses the turbocharger exhaust turbine in the exhaust passage is provided in the exhaust passage, and a bypass passage opening/closing valve that opens and closes the exhaust bypass passage is provided, the exhaust passage being downstream of the compressor of the turbocharger and located on the carburetor throttle valve. A diaphragm of an actuator that opens and closes the bypass passage opening/closing valve is provided with a pressure guiding port in the intake passage on the upstream side of the carburetor throttle valve, which is a position that is not affected by pressure changes due to the opening/closing state of the valve. The pressure guiding passage is provided in communication with the chamber, and the pressure guiding passage is provided with a pressure holding mechanism and a pressure drop delay mechanism, and the pressure holding mechanism is adapted to control the pressure guided by the pressure guiding passage and acting on the diaphragm chamber. The pressure drop delay mechanism is configured to reduce the vibration of the diaphragm chamber and open the bypass passage opening/closing valve by holding the pressure acting on the diaphragm chamber for a certain period of time during the closing operation of the vaporizer throttle valve, and the pressure drop delay mechanism When the pressure is above a predetermined value, the pressure is immediately applied to the diaphragm chamber, and when the pressure from the pressure impulse port is less than a predetermined value and the pressure in the pressure passage is decreased, the rate of decrease of the pressure is The supercharging pressure control for a supercharged engine is characterized in that the boost pressure control for a supercharged engine is characterized in that the pressure acting on the diaphragm chamber is held for a certain period of time in cooperation with the pressure holding mechanism, and the bypass passage opening/closing valve is opened. Device.