JPH04370324A - Deceleration air bypass valve control device for engine having supercharger - Google Patents

Abstract

PURPOSE:To prevent rise of intake air temperature due to recirculation of supercharge air and sufficiently lower pulsation noise due to surging. CONSTITUTION:An air bypass valve 62 installed in an air bypass path 61 is so constituted that the valve may opens by means of a difference between a supercharge pressure acting on a diaphragm 626 installed in a valve body 62a and a supercharge pressure acting on a diaphragm chamber 62c. The diaphragm chamber 62c and the upstream side from a compressor 7b, 8b are mutually connected so that the two also communicate with each other through the 1st pressure introduction path 63. In the 1st pressure introduction path 63, a positive pressure delay valve 64 for introducing the supercharge pressure upstream from the compressor to the diaphragm chamber 62c by delaying it, is disposed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deceleration air bypass valve control device for preventing surging during deceleration in a supercharged engine.

0002

[Prior Art] In an engine equipped with a turbocharger, when the throttle valve suddenly switches from an open state to a closed state due to deceleration, the throttle valve is closed due to the intake inertia and the rotational inertia of the compressor. Upstream pressure increases rapidly. This rapid pressure increase causes surging in which supercharged air flows back toward the compressor due to pressure reflection, leading to the problem of pulsating noise.

[0003] As an example of a technique for reducing this pulsating sound,
Japanese Utility Model Publication No. 64-58723 and Publication of Utility Model Publication No. 63-983 are known. In the former case, as shown in FIG. 6, when the throttle valve 1 is suddenly closed, the negative pressure downstream of the throttle valve is introduced into the diaphragm chamber 2a of the air bypass valve 2;
The air bypass valve 2 is opened by the positive pressure upstream of the throttle valve acting on the diaphragm 2c provided with the valve body 2b,
The boost pressure downstream of the compressor 3 is bypassed to the upstream side of the compressor 3. The latter directs negative pressure downstream of the throttle valve directly to one diaphragm chamber of the air bypass valve when the throttle valve is suddenly closed, and also directs negative pressure (differential pressure) to the other diaphragm chamber via a negative pressure delay valve.
to open the air bypass valve.

0004

However, the device disclosed in the above-mentioned publication also has problems to be solved. (b) In a device like the one disclosed in Japanese Utility Model Application Publication No. 64-58723, in which the air bypass valve opens with the sum of the intake pipe negative pressure and the compressor pressure, as shown in Fig. 6, under the partial condition where the engine speed is high, the turbo Since the charger is rotating sufficiently, the air bypass valve opens due to negative pressure and positive pressure, causing the problem that the supercharged air is repeatedly recirculated and the intake temperature rises abnormally. An increase in intake temperature causes a problem in that the durability and reliability of the compressor and the durability and reliability of rubber hoses related to the intake duct are reduced. (b) In the device disclosed in Japanese Utility Model Publication No. 63-983, the opening of the air bypass valve is controlled only by the negative pressure (differential pressure) introduced into the diaphragm chamber, so the opening timing of the air bypass valve during deceleration is delayed. It is not possible to sufficiently reduce the occurrence of surging immediately after deceleration.

The present invention focuses on the above-mentioned problems, and provides a supercharged engine that can prevent an increase in intake temperature due to recirculation of supercharged air and can sufficiently reduce the occurrence of surging. An object of the present invention is to provide a deceleration air bypass valve control device.

[0006]

[Means for Solving the Problems] A deceleration air bypass valve control device for a supercharged engine according to the present invention in accordance with this object is capable of communicating the upstream and downstream sides of a compressor of a turbocharger via an air bypass passage. A supercharged engine is provided with a diaphragm type air bypass valve connected to the air bypass passage and guiding the pressure downstream of the compressor to the upstream side of the compressor, and is configured as follows.

(1) The air bypass valve is constructed so that it can be opened by the differential pressure between the supercharging pressure acting on the diaphragm provided with the valve body and the supercharging pressure acting on the diaphragm chamber,
A positive pressure delay in which the diaphragm chamber and the upstream side of the compressor are communicatively connected via a first pressure introduction passage, and the supercharging pressure downstream of the compressor is delayed and introduced into the diaphragm chamber through the first pressure introduction passage. Interpose a valve. (2) The air bypass valve is configured to be openable by at least one of supercharging pressure acting on a diaphragm provided with a valve body and negative pressure acting on a diaphragm chamber, and the diaphragm chamber is opened by introducing a second pressure. It is communicated via a passage with a port that has negative pressure when the throttle valve is fully closed.

[0008]

[Operations] In the thus constructed deceleration air bypass valve control device for a supercharged engine, the following operations are performed. In the above configuration (1), immediately after deceleration, the pressure upstream of the throttle valve increases rapidly, and this rapidly increased pressure acts on the diaphragm of the air bypass valve. Since the diaphragm is equipped with a valve body,
As the diaphragm is displaced by the sudden increase in pressure, the valve body moves and the air bypass valve is opened. In this case, the pressure in the diaphragm chamber is also led to the diaphragm chamber through the first pressure introduction passage, but since the first pressure introduction passage is equipped with a positive pressure delay valve, the pressure in the diaphragm chamber is suddenly increased. does not rise. Therefore, immediately after deceleration, the pressure acting on the side of the diaphragm where the valve body is installed,
The difference in pressure acting within the diaphragm chamber varies greatly,
This differential pressure causes the air bypass valve to open quickly. As a result, supercharging air existing between the throttle valve and the compressor is bypassed to the upstream side of the compressor, and pulsating noise due to surging is reduced. Also, during supercharging after deceleration, supercharging pressure is guided to the diaphragm chamber of the air bypass valve via the positive pressure delay valve.
The air bypass valve is closed. Therefore, recirculation of supercharged air is prevented, and an increase in intake temperature is prevented.

In the configuration (2) above, immediately after deceleration, the pressure upstream of the throttle valve increases rapidly, and this rapidly increased pressure acts on the diaphragm in which the valve body of the air bypass valve is provided. In addition, since negative pressure is introduced into the diaphragm chamber via the second pressure introduction passage from the port that becomes negative pressure when the throttle valve is fully closed, the air bypass valve has a positive pressure acting on the diaphragm provided with the valve body. The valve opens quickly due to pressure and negative pressure acting on the diaphragm chamber. That is, since both the positive pressure and the negative pressure in this case act to open the air bypass valve, the responsiveness of the valve opening operation is improved compared to the case where pressure acts on either one. This makes it possible to sufficiently reduce the occurrence of surging.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the deceleration air bypass valve control device for a supercharged engine according to the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 3 show a first embodiment of the present invention.
In particular, it shows the case where it is applied to a 6-cylinder engine mounted on a vehicle. In FIG. 2, 1 is an engine, 2 is a surge tank, and 3 is an exhaust manifold. Exhaust manifold 3 connects #1 to #3 cylinder groups and #4 to #4 without exhaust interference.
Two #6 cylinder groups are assembled, and the gathering part is the communication passage 3a.
communicated by. 7 and 8 are a main turbocharger and a sub-turbocharger arranged in parallel with each other. Turbines 7a and 8 of turbochargers 7 and 8, respectively
a is connected to a gathering part of the exhaust manifold 3, and each compressor 7b, 8b is connected to the surge tank 2 via an intercooler 6 and a throttle valve 4.

The main turbocharger 7 is operated from a low intake air amount region to a high intake air amount region, and the auxiliary turbocharger 8 is stopped in a low intake air amount region. In order to enable operation and stop of both turbochargers 7 and 8, an exhaust switching valve 1 is provided downstream of the turbine 8a of the auxiliary turbocharger 8.
7, an intake switching valve 18 is provided downstream of the compressor 8b. When both the intake and exhaust switching valves 18 and 17 are open, both turbochargers 7 and 8 are operated. The downstream side of the turbine 8 a of the auxiliary turbocharger 8 and the downstream side of the turbine 7 a of the main turbocharger 7 can communicate with each other via an exhaust bypass passage 40 . The exhaust bypass passage 40 is provided with an exhaust bypass valve 41 that opens and closes the exhaust bypass passage 40. Exhaust bypass valve 41
are opened and closed by a diaphragm actuator 42.

The intake passage of the auxiliary turbocharger 8, which is stopped in the low intake air amount region, has one turbocharger and two
In order to smoothly switch to the individual turbocharger, an intake bypass passage 13 that communicates between the upstream of the compressor 7b and the downstream of the compressor 8b, and an intake bypass valve 33 disposed in the middle of the intake bypass passage 13 are provided. . The intake bypass valve 33 is a diaphragm type actuator 1
Opened and closed by 0. A check valve 12 is provided in a bypass passage that communicates the upstream and downstream sides of the intake switching valve 18 , and when the intake switching valve 18 is closed, the compressor outlet pressure on the sub-turbocharger 8 side reaches the main turbocharger 7 .
When the side becomes larger than the side, air can flow from the upstream side to the downstream side. In the figure, 14 indicates an intake passage on the compressor outlet side, and 15 indicates an intake passage on the compressor inlet side. The intake passage 15 is connected to an air cleaner 23 via an air flow meter 24. A front pipe 20 forming an exhaust passage is connected to an exhaust muffler (not shown) via an exhaust gas catalyst 21. The intake switching valve 18 is opened and closed by the actuator 11, and the exhaust switching valve 17 is opened and closed by the diaphragm type actuator 16. The waste gate valve 31 is opened and closed by an actuator 9.

Actuators 9, 10, 11, 16, 4
2 is operated by introducing supercharging pressure or negative pressure. Each actuator 9, 10, 11, 16,
42 includes first, second, third, fourth, fifth, and 6th
Solenoid valves 25, 26, 27, 28, 32, and 44 are connected. Each solenoid valve 25, 26, 27, 28, 32, 4
4 is performed according to a command from the engine control computer 29. Note that the second solenoid valve 26
A check valve 45 that allows only one flow of negative pressure is interposed in the passage for introducing negative pressure into the valve.

[0015] When the first solenoid valve 25 is ON, the intake switching valve 1
The actuator 11 is operated so as to fully open 8.
OFF operates the actuator 11 to fully close the intake switching valve 18. When the fourth solenoid valve 28 is turned ON, the actuator 16 is actuated to fully open the exhaust switching valve 17, and when it is OFF, the actuator 10 is actuated to fully close the exhaust switching valve 17. O of the third solenoid valve 27
N operates the actuator 10 to fully close the intake bypass valve 33, and OFF operates the actuator 10 to fully open the intake bypass valve 33.

The fifth solenoid valve 32 that introduces atmospheric pressure into the actuator 42 that operates the exhaust bypass valve 41 is
N, not OFF control but duty control. Similarly, the sixth solenoid valve 44 that guides supercharging pressure to the actuator 9 that operates the waste gate valve 31 is also turned on and off.
It is not controlled but is duty controlled. As is well known, duty control is to control the energization time by the duty ratio, and by digitally changing the ratio of energization and non-energization, the average current is variably controlled in an analog manner. Note that the duty ratio is the ratio of the energizing time to the time of one cycle, and if the energizing time in one cycle is A and the non-energizing time is B, then the duty ratio = A / (A + B) ×
It is expressed as 100 (%). In this embodiment, by controlling the duty of the fifth solenoid valve 32 and the sixth solenoid valve 44, it is possible to vary the opening amounts of these solenoid valves.

The opening degree of the exhaust bypass valve 41 is determined by varying the amount of bleed (leak amount) of the supercharging pressure introduced into the diaphragm chamber 42a of the actuator 42 into the atmosphere by controlling the duty of the fifth solenoid valve 32. It is variable. The opening degree of the waste gate valve 31 is determined by controlling the amount of bleed (leak amount) of the supercharging pressure introduced into the diaphragm chamber 9b of the actuator 9 to the atmosphere.
It can be made variable by changing the duty control of No. 4.

The engine control computer 29 is electrically connected to sensors for detecting various operating conditions of the engine, and receives signals from the various sensors. The engine operating condition detection sensors include an intake pipe pressure sensor 30, a throttle opening sensor 5, an air flow meter 24 as an intake air amount measuring sensor, an engine speed sensor 50, and an oxygen sensor 19. The engine control computer 29 includes a central processor unit (CPU) for calculations, a read-only memory (ROM), a random access memory (RAM) for temporary storage, and an input/output interface (I/O interface).
(O interface), and an A/D converter that converts analog signals from various sensors into digital quantities.

Compressor 7b of main turbocharger 7
and an intake passage 14 located downstream of the compressor 8b of the sub-turbocharger 8.
An air bypass passage 61 that guides the supercharged air downstream of the compressors 7b and 8b to the upstream side of the compressors 7b and 8b is connected to the vicinity of the merging portion 14c where the compressors 7b and 8b merge. The air bypass passage 61 has compressors 7b and 8b when the valve is opened.
An air bypass valve 62 is provided that allows the downstream supercharging air to flow upstream of the compressors 7b and 8b.

The air bypass valve 62 is configured to be openable by the differential pressure between the supercharging pressure acting on the diaphragm 62b on which the valve body 62a is provided and the supercharging pressure acting on the diaphragm chamber 62c. In the diaphragm chamber 62c,
A compression coil spring 62d is provided that biases the diaphragm 62b in the valve closing direction. Diaphragm chamber 62
In a state where negative pressure is introduced to c, the diaphragm 62b is displaced toward the compression coil spring 62d, and the air bypass valve 62 is opened.

The diaphragm chamber 62c of the air bypass valve 62 is connected to the intake passage 1 via the first pressure introduction passage 63.
It is possible to communicate with the vicinity of the confluence section 14c of No. 4. A positive pressure delay valve 64 is installed in the first pressure introduction passage 63 to delay and introduce supercharging pressure into the diaphragm chamber 62c of the air bypass valve 62. In the positive pressure delay valve 64, a check valve 64a serving as a passage and a throttle portion 64b are arranged in parallel. The check valve 64a connects the air bypass valve 62 from the diaphragm chamber 62c side to the confluence section 14.
It has a function of only allowing intake air to flow to the c side. Aperture part 6
4b throttles the flow rate of intake air flowing from the confluence section 14c side to the diaphragm chamber 62c side to a certain amount, and
It has a function of preventing the pressure inside 2c from rising rapidly due to the introduction of supercharging air.

Next, the operation of the first embodiment will be explained. In the high intake air amount region, both the intake switching valve 18 and the exhaust switching valve 17 are opened, and the intake bypass valve 33 is closed. As a result, the two turbochargers 7 and 8 are driven, a sufficient amount of supercharging air is obtained, and the output is improved. In a low speed range and under high load, both the intake switching valve 18 and the exhaust switching valve 17 are closed, and the intake bypass valve 33 is opened. As a result, only one turbocharger 7 is driven. The reason why one turbocharger is used in the low intake air amount range is that the supercharging characteristics of one turbocharger are superior to the supercharging characteristics of two turbochargers in the low intake air amount range. By using one turbocharger,
Boost pressure and torque rise faster, resulting in faster response. When transitioning from a low intake air amount region to a high intake air amount region, that is, when switching from one turbocharger operation to two turbocharger operation, the exhaust bypass valve is closed while the intake switching valve 18 and the exhaust switching valve 17 are closed. 41 is slightly opened by duty control and further closes the intake bypass valve 33 to increase the run-up rotation speed of the auxiliary turbocharger 8, making it possible to switch the turbocharger more smoothly (with less shock during switching). become.

Immediately after deceleration, the pressure upstream of the throttle valve 4 rapidly increases due to the closing of the throttle valve 4, and this rapidly increased pressure acts on the diaphragm 62b of the air bypass valve 62. The diaphragm 62b is displaced toward the compression coil spring 62d by this pressure, and the diaphragm 62b is displaced toward the compression coil spring 62d.
The air bypass valve 62 is opened by the movement of the valve body 62a in accordance with the displacement of b. Here, diaphragm chamber 6
2c as well, the pressure that has suddenly increased is introduced through the first pressure introduction passage 63, but since a positive pressure delay valve 64 is installed in the first pressure introduction passage 63, the pressure inside the diaphragm chamber 62c is The introduced supercharging air prevents the air from rising rapidly. Therefore, immediately after deceleration, the diaphragm 62b can be easily displaced by the rapidly increased supercharging pressure, and the air bypass valve 62 can be opened quickly. Therefore, the high pressure intake air is transferred to the air bypass valve 62.
The air is bypassed to the upstream side of the compressors 7b and 8b through the air, thereby preventing the generation of abnormal noise due to surging.

[0024] In the so-called partial state when the opening degree of the throttle valve 4 is located between idling and fully open, supercharging air is led to the diaphragm chamber 62c of the air bypass valve 62, so the air bypass passage 61 is closed. It is closed by the movement of the valve body 62a in conjunction with the displacement of the diaphragm 62b. Therefore, recirculation of supercharged air through the air bypass passage 61 is reliably prevented, and an increase in intake air temperature is prevented.

Second Embodiment FIGS. 4 and 5 show a second embodiment of the present invention. This embodiment differs from the first embodiment only in the operating configuration of the air bypass valve, and other parts are similar to the first embodiment, so similar parts are designated by the same reference numerals as in the first embodiment. The explanation of the corresponding parts will be omitted, and the different parts will be explained.

In the first embodiment, the boost pressure downstream of the compressors 7b and 8b is guided to the diaphragm chamber 62c via the positive pressure delay valve 64, but in this embodiment, the positive pressure delay valve 64 is not used. The structure is as follows. In Figure 4,
The diaphragm chamber 62c can communicate with a port 72 arranged near the throttle valve 4 via a second pressure introduction passage 71. The port 72 is arranged at a position where the pressure is negative when the throttle valve 4 is fully closed. When negative pressure is introduced into the diaphragm chamber 62c through the second pressure introduction passage 71, the diaphragm 62b is displaced toward the compression coil spring 62d, and the air bypass valve 62 is opened.

In the second embodiment configured as described above, immediately after deceleration, the pressure of the supercharging air upstream of the throttle valve 4 rises rapidly, and this sudden rise in supercharging pressure causes the diaphragm 62b of the air bypass valve 62 to open. Displaced in the direction of the valve. In addition, in this state, the negative pressure from the port 72 which becomes negative pressure when the throttle valve 4 is fully closed is transferred to the second pressure introduction passage 71.
is guided to the diaphragm chamber 62c via the diaphragm chamber 62c. Therefore,
The air bypass valve 62 is quickly opened by the supercharging pressure (positive pressure) acting on the diaphragm 62b side and the negative pressure introduced into the diaphragm chamber 62c. In other words, by using the negative pressure, the displacement of the diaphragm 62b is faster than when opening the valve using only boost pressure, and the responsiveness of the valve opening operation is significantly improved. Therefore, the supercharging pressure increased by the sudden closing of the throttle valve 4 is instantly transferred to the compressor 7b.
, 8b can be bypassed to the upstream side, and generation of pulsating noise due to surging is prevented.

[0028] In each of the above embodiments, a two-stage twin turbo engine is described in which two turbochargers are provided for one engine, but one turbocharger is provided for one engine. Of course, it can also be applied to engines.

[0029]

[Effects of the Invention] As explained above, according to the present invention,
The following effects can be obtained. (a) The air bypass valve is constructed so that it can be opened by the differential pressure between the boost pressure acting on the diaphragm provided with the valve body and the boost pressure acting on the diaphragm chamber, and the diaphragm chamber of the air bypass valve and the turbocharger A positive pressure delay valve is connected to the upstream side of the compressor through a first pressure introduction passage, and the first pressure introduction passage is provided with a positive pressure delay valve that delays the supercharging pressure upstream of the compressor of the turbocharger and introduces it into the diaphragm chamber. Immediately after deceleration, the supercharged air downstream of the compressor, where the pressure has suddenly increased, can be bypassed to the upstream side of the compressor, and it is possible to prevent the generation of abnormal noise due to surging. In addition, after deceleration, compressor pressure is guided to the diaphragm chamber via the positive pressure delay valve, so the air bypass valve is closed and the recirculation of supercharged air, which causes an increase in intake temperature, can be prevented. .

(b) The air bypass valve is configured to be openable by at least one of boost pressure acting on the diaphragm provided with the valve body and negative pressure acting on the diaphragm chamber, and the diaphragm chamber of the air bypass valve is communicated via the second pressure introduction passage with a port that has negative pressure when the throttle valve is fully closed, increasing the responsiveness of the valve opening operation compared to a configuration in which the valve is opened only by boost pressure. be able to. Therefore, the occurrence of surging immediately after deceleration can be sufficiently reduced, and the occurrence of pulsating noise can be significantly suppressed.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a deceleration air bypass valve control device for a supercharged engine according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a supercharged engine equipped with the device of FIG. 1;

FIG. 3 is a partially enlarged sectional view of FIG. 2;

FIG. 4 is a schematic configuration diagram of a deceleration air bypass valve control device for a supercharged engine according to a second embodiment of the present invention.

5 is a system diagram of a supercharged engine equipped with the device of FIG. 4. FIG.

FIG. 6 is a schematic configuration diagram of a conventional deceleration air bypass valve control device.

[Explanation of symbols]

4 Throttle valve 7 Main turbocharger 7b Compressor 8 Sub-turbocharger 8b Compressor 61 Air bypass passage 62 Air bypass valve 62a Valve body 62b diaphragm 62c Diaphragm chamber 63 First pressure introduction passage 64 Positive pressure delay valve 71 Second pressure introduction passage

Claims (2)

[Claims] 1. A diaphragm-type air bypass that connects the upstream and downstream sides of a compressor of a turbocharger so that they can communicate through an air bypass passage, and guides supercharged air downstream of the compressor to the upstream side of the compressor. In a supercharged engine provided with a valve, the air bypass valve is configured to be openable by a pressure difference between supercharging pressure acting on a diaphragm provided with a valve body and supercharging pressure acting on a diaphragm chamber, A positive pressure delay in which the diaphragm chamber and the downstream side of the compressor are communicatively connected via a first pressure introduction passage, and the supercharging pressure downstream of the compressor is delayed and introduced into the diaphragm chamber through the first pressure introduction passage. A deceleration air bypass valve control device for a supercharged engine, characterized in that a valve is installed. 2. A diaphragm-type air bypass that connects the upstream and downstream sides of the compressor of the turbocharger so as to communicate through an air bypass passage, and guides supercharged air downstream of the compressor to the upstream side of the compressor. In a supercharged engine provided with a valve, the air bypass valve is configured to be openable by at least one of supercharging pressure acting on a diaphragm provided with a valve body and negative pressure acting on a diaphragm chamber, A deceleration air bypass valve control device for a supercharged engine, characterized in that the diaphragm chamber is communicated via a second pressure introduction passage with a port that becomes a negative pressure when a throttle valve is fully closed.