JPH0598984A - Deceleration air bypass valve device of engine with supercharger - Google Patents

Abstract

PURPOSE:To reduce abnormal sounds generated by chattering of a valve element of an air bypass valve. CONSTITUTION:A diaphragm type air bypass valve 62 is provided in an air bypass path 61 affording communication connectively between the upstream and downstream parts of a compressor 7b for a turbocharger 7. A first throttle section 71 having a diameter d2 smaller than a bore d1 of a valve seat 62d on which a valve element 62c of the air bypass valve 62 is seated is provided right downstream of the air bypass valve 62, so that the pulsation of supercharging gas due to chattering of the valve element 62c is damped.

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 device for preventing the occurrence of surging during deceleration in a supercharged engine.

[0002]

2. Description of the Related Art In an engine equipped with a supercharger (turbocharger), when the throttle valve is suddenly switched from the open state to the closed state due to deceleration, the intake valve inertia and the rotational inertia of the compressor cause throttle valve The upstream pressure rises sharply. This abrupt pressure increase causes a problem that supercharging causes surging that flows back to the compressor side due to pressure reflection, and pulsating noise is generated.

As an example of a technique for reducing this pulsating sound,
A device as disclosed in Japanese Utility Model Publication No. 1-58723 is known. In this device, the air bypass valve is opened during deceleration and the supercharged air compressed by the compressor is returned to the upstream side of the compressor, so that the occurrence of surging during deceleration is suppressed.

FIG. 7 shows an example of a conventional air bypass valve device. As shown in FIG. 7, the upstream side and the downstream side of the compressor 91 a of the turbocharger 91 are communicably connected via an air bypass passage 92. A diaphragm type air bypass valve 93 is provided in the air bypass passage 92. The valve body 93b is provided on the outer surface of the diaphragm 93a of the air bypass valve 93.
Is installed. A compression spring 93d for pressing the diaphragm 93a in the valve closing direction is housed in the diaphragm chamber 93c of the air bypass valve 93.

The diaphragm chamber 93c of the air bypass valve 93 is provided with a throttle valve 9 through a sensing passage 94.
It is connected to the downstream of 5. Air bypass valve 93
In the light load region, the valve is opened by the negative pressure of the intake pipe introduced into the diaphragm chamber 93c, and conversely, in the high load region, the valve is closed by the supercharging pressure introduced into the diaphragm chamber 93c.

[0006]

However, the apparatus shown in FIG. 7 has the following problems. As described above, the air bypass valve 93 is opened by the intake pipe negative pressure introduced into the diaphragm chamber 93c in the light load region, and conversely closed by the supercharging pressure introduced into the diaphragm chamber 93c in the high load region. However, there is a region where the valve closing force and the valve opening force are balanced between the light load region and the high load region. In this region, the position of the valve body 93b is not stable, and a phenomenon in which the valve body 93b repeats the opening / closing operation, that is, a so-called chattering phenomenon occurs.

When the valve body 93b causes chattering, a new pulsating sound is generated, and this pulsating sound is generated by the air bypass passage 92.
Then, there is a problem in that the sound is returned to the air cleaner 96 side and an abnormal noise is heard in the passenger compartment. The generation of this abnormal sound gives an occupant of the vehicle an unpleasant sensation, and a solution is desired.

In view of the above problems, it is an object of the present invention to provide a deceleration air bypass valve device capable of reducing the occurrence of abnormal noise due to chattering of the valve body of the air bypass valve.

[0009]

The deceleration air bypass valve device for a supercharged engine according to the present invention, which is directed to this object, enables communication between the upstream side and the downstream side of a compressor of a turbocharger via an air bypass passage. A diaphragm type air bypass valve is provided in the air bypass passage, and the air bypass valve is opened by a negative pressure introduced into the diaphragm chamber and closed by a supercharging pressure introduced into the diaphragm chamber. The deceleration air bypass valve device for the engine with a supercharger configured is configured as follows.

(1) A first throttle portion having a diameter smaller than a diameter of a valve seat on which a valve body of the air bypass valve is seated is provided immediately downstream of the air bypass valve in the air bypass passage.

(2) In the sensing passage for introducing the negative pressure or the supercharging pressure into the diaphragm chamber of the air bypass valve, the second throttle portion located at the antinode portion of the air column vibration generated when the valve body of the air bypass valve chatters. It is provided with.

[0012]

In the deceleration air bypass valve device for a supercharged engine thus constructed, the following actions are performed.

In the above configuration (1), since the first throttle portion has a diameter smaller than the hole diameter of the valve seat on which the valve body of the air bypass valve is seated, it flows out of the air bypass valve. The throttle effect of the supercharged air flow is enhanced, and the effect of damping the pulsation of the supercharged air flowing through the air bypass passage becomes large. Therefore, the transmission of the pulsating sound to the air cleaner side due to the chattering of the valve body is reduced, and the generation of abnormal noise due to the pulsating sound is reduced.

In the above configuration (2), since the second throttle portion is located at the portion of the air column vibration that occurs when the valve body of the air bypass valve chatters in the sensing passage, the air column vibration is damped. The effect is increased, and it is possible to significantly reduce the air column vibration. As a result, pressure fluctuations in the diaphragm chamber are suppressed, and chattering of the valve body is suppressed. By suppressing chattering of the valve body, the pulsating sound transmitted to the air cleaner side is reduced, and the generation of abnormal noise due to the pulsating sound is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a deceleration air bypass valve 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.
Especially, the case where the present invention is applied to a 6-cylinder engine mounted on a vehicle is shown. In FIG. 2, 1 is an engine, 2 is a surge tank, and 3 is an exhaust manifold. The exhaust manifold 3 includes # 1 to # 3 cylinder groups and # 4 to
Two groups of # 6 cylinders are assembled, and the assembly part is the communication passage 3a.
Is communicated by. Reference numerals 7 and 8 denote a main turbocharger and a sub turbocharger arranged in parallel with each other.
Turbine 7a, 8 of turbocharger 7, 8 respectively
The a is connected to the collecting portion of the exhaust manifold 3, and the compressors 7b and 8b are connected to the surge tank 2 via the intercooler 6 and the throttle valve 4.

The main turbocharger 7 is operated from the low intake air amount region to the high intake air amount region, and the auxiliary turbocharger 8 is stopped in the low intake air amount region. The exhaust switching valve 1 is provided downstream of the turbine 8a of the auxiliary turbocharger 8 in order to enable operation and stop of both turbochargers 7 and 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 8a of the sub turbocharger 8 and the downstream side of the turbine 7a 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 type actuator 42.

In the intake passage of the auxiliary turbocharger 8 which is stopped in the low intake air amount range, one turbocharger to two is installed in the intake passage.
In order to facilitate the switching to the individual turbocharger, an intake bypass passage 13 that connects the upstream side of the compressor 7b and the downstream side 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.
It is opened and closed by 0. A check valve 12 is provided in a bypass passage that connects upstream and downstream of the intake switching valve 18, and when the intake switching valve 18 is closed, the compressor outlet pressure on the side of the auxiliary turbocharger 8 is the main turbocharger 7.
When larger than the side, air is allowed to 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 the air cleaner 23 via an air flow meter 24. The front pipe 20 forming the 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 actuator 16. The waste gate valve 31 is adapted to be opened and closed by the actuator 9.

Actuators 9, 10, 11, 16, 4
2 is activated by the introduction of supercharging pressure or negative pressure. Each actuator 9, 10, 11, 16,
Reference numeral 42 denotes a first pressure tank 51, a supercharging pressure from the compressor outlet side 14, or a negative pressure of the surge tank 2 and a first pressure, a second pressure, in order to selectively switch the atmospheric pressure from the downstream of the air flow meter 24. Third, fourth, fifth and sixth solenoid valves 2
5, 26, 27, 28, 32, 44 are connected.
Switching of each solenoid valve 25, 26, 27, 28, 32, 44 is performed according to a command from the engine control computer 29. A check valve 45 that allows only one flow of the negative pressure is provided in the passage for introducing the negative pressure to the second solenoid valve 26.

When the first solenoid valve 25 is turned ON, the intake switching valve 1
Actuating the actuator 11 so that 8 is fully opened,
When OFF, the actuator 11 is operated so that the intake switching valve 18 is fully closed. When the fourth solenoid valve 28 is turned on, the actuator 16 is operated so as to fully open the exhaust gas switching valve 17, and when it is turned off, the actuator 10 is operated so as to fully close the exhaust gas switching valve 17. O of the third solenoid valve 27
N operates the actuator 10 so as to fully close the intake bypass valve 33, and OFF operates the actuator 10 so as to fully open the intake bypass valve 33.

A fifth step of bleeding the supercharging pressure applied to the actuator 42 for operating the exhaust bypass valve 41 to the atmosphere
The solenoid valve 32 is subjected to duty control instead of ON / OFF control. Similarly, the sixth solenoid valve 44 that bleeds the boost pressure applied to the actuator 9 that operates the wastegate valve 31 to the atmosphere is not ON / OFF controlled but is duty controlled. As is well known, the duty control is to control the energization time by the duty ratio, and the average current is variably controlled in an analog manner by digitally changing the ratio of energization and non-energization. The duty ratio is the ratio of the energization time to the time of one cycle, and when the energization time in one cycle is A and the non-energization time is B, the duty ratio = A / (A + B) × 100.
It is represented by (%). In the present embodiment, the fifth solenoid valve 32
And by controlling the duty of the sixth solenoid valve 44,
It is possible to change the opening amount of these solenoid valves.

The opening degree of the exhaust bypass valve 41 is controlled by changing the bleed amount (leak amount) of the boost pressure introduced into the diaphragm chamber 42a of the actuator 42 to 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 set so that the bleed amount (leak amount) of the supercharging pressure introduced into the diaphragm chamber 9b of the actuator 9 to the atmosphere is determined by the sixth solenoid valve 4.
It can be changed by changing the duty control of No. 4.

Engine control computer 29
Is electrically connected to various operating condition detection sensors of the engine and receives signals from the various sensors. The engine operating condition detection sensor includes 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 calculation, a read only memory (ROM) which is a read-only memory, a random access memory (RAM) for temporary storage, and an input / output interface (I).
/ O interface) and an A / D converter for converting analog signals from various sensors into digital quantities.

Compressor 7b of main turbocharger 7
Of the intake passage 14a located downstream of the compressor 8b of the auxiliary 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 near the confluence portion 14c where the b and the b merge. The air bypass passage 61 has the compressors 7b, 8b when the valve is opened.
An air bypass valve 62 is provided to allow the supercharged air on the downstream side to flow to the upstream side of the compressors 7b and 8b.

As shown in FIG. 1, the air bypass valve 62 has a displaceable diaphragm 62a and a diaphragm chamber 62b formed by the diaphragm 62a. The valve body 62 is provided on the outer surface of the diaphragm 62a.
c is attached. A valve seat 62d on which the valve body 62c is seated is provided at a position facing the valve body 62c of the air bypass valve 62. A compression spring 62e that biases the diaphragm 62a in the valve closing direction is arranged in the diaphragm chamber 62b.

The inside of the diaphragm chamber 62b communicates with the downstream side of the throttle valve 4 via a sensing passage 63. In the light load region of the engine, the intake pipe negative pressure is introduced into the diaphragm chamber 62b through the sensing passage 63, and the displacement of the diaphragm 62a causes the valve body 62c to move to the valve seat 62.
The air bypass valve 62 is opened by moving away from d. In the high load region of the engine, the supercharging pressure is introduced into the diaphragm chamber 62b through the sensing passage 63, and the displacement of the diaphragm 62a causes the valve body 62c to come into close contact with the valve seat 62d, thereby closing the air bypass valve 62. It is supposed to do.

Immediately downstream of the air bypass valve 62 in the air bypass passage 61, there is provided a first throttle portion 71 which throttles the flow of supercharged air flowing through the air bypass passage 61.
The diameter d ₂ of the first throttle portion 71 is equal to that of the air bypass valve 62.
Is smaller than the hole diameter d ₁ of the valve seat 62d on which the valve body 62c is seated.

Next, the operation of the first embodiment will be described. 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 supercharged air is obtained, and the output is improved. Both the intake switching valve 18 and the exhaust switching valve 17 are closed and the intake bypass valve 33 is opened in the low speed range and at the time of high load. As a result, only one turbocharger 7 is driven. The reason why one turbocharger is used in the low intake air amount region is that the one turbocharger supercharging characteristic is superior to the two turbocharger supercharging characteristic in the low intake air amount region. By using one turbocharger, the boost pressure and torque rise faster, and the response becomes faster.

When shifting from the low intake air amount region to the high intake air amount region, that is, when switching from one turbocharger operation to two turbocharger operation, the intake switching valve 18
When the exhaust switching valve 17 is closed, the exhaust bypass valve 41 is controlled to be small open by duty control, and the intake bypass valve 33 is closed to increase the running speed of the auxiliary turbocharger 8 to switch the turbocharger. It becomes possible to carry out more smoothly (small shock when switching).

Immediately after deceleration, the pressure on the upstream side of the throttle valve rises sharply due to the closing of the throttle valve 4. However, in this state, the pressure on the downstream side of the throttle valve 4 becomes negative, so the diaphragm chamber 62b of the air bypass valve 62 has a negative pressure. Pressure is introduced,
The air bypass valve 62 is opened. As a result, the supercharged air compressed by the compressors 7b, 8b of the turbochargers 7, 8 is returned to the upstream of the compressors 7b, 8b via the air bypass passage 61. Therefore, the occurrence of surging in which the supercharged air flows back to the compressor side due to pressure reflection is prevented.

As described above, in the light load region, the air bypass valve 62 is opened by the intake pipe negative pressure introduced into the diaphragm chamber 62b, and conversely, in the high load region, the supercharging pressure introduced into the diaphragm chamber 62b. Although the valve will be closed by the valve, there is a region where the valve closing force and the valve opening force are balanced in the middle of the light load region and the high load region.
A phenomenon in which 2c repeats the opening / closing operation, a so-called chattering phenomenon occurs. The chattering phenomenon generates a new pulsating sound and causes an abnormal noise in the vehicle interior. In the present embodiment, the first throttling portion 71 provided in the air bypass passage 61 reduces the abnormal noise. ..

Since the first throttle portion 71 has a diameter d ₂ smaller than the hole diameter d ₁ of the valve seat 62d on which the valve body 62c of the air bypass valve 62 is seated, the valve seat hole of the air bypass valve 62 is formed. The effect of restricting the flow of supercharged air that has flowed out from is enhanced, and the effect of damping the pulsation of supercharged air becomes great. Therefore, the transmission of the pulsating sound due to the chattering of the valve body 62c to the air cleaner 23 side is reduced, and the abnormal noise in the vehicle interior is reduced.

Second Embodiment FIGS. 4 to 6 show a second embodiment of the present invention.
The second embodiment is different from the first embodiment only in the structure of the diaphragm portion, and the other parts are the same as those in the first embodiment.
The description of the corresponding parts will be omitted, and only different parts will be described.

As shown in FIG. 4, the sensing passage 63 is provided with a second throttle portion 75. As shown in FIG. 5, the flow passage cross-sectional area of the sensing passage 63 is locally reduced by the second throttle portion 75. As shown in FIG. 6, the second throttle portion 75 is provided so as to be located at a portion of the antinode S ₁ of the air column vibration S that occurs when the valve body 62c of the air bypass valve 62 in the sensing passage 63 chatters. ..

In the present embodiment, the second throttle portion 75 is provided at a position separated by a distance L from the portion where the sensing passage 63 opens to the diaphragm chamber 62b. The distance L is calculated by the following equation. L = n / 2 · υ / f where υ is the speed of sound, n is the number of antinodes of air column vibration generated in the sensing passage (1, 2, 3, 4, ...), and f is the frequency. ..

In the second embodiment constructed as described above, the second throttle portion 75 has a portion of the antinode S ₁ of the air column vibration S generated when the valve body 62c of the air bypass valve 62 in the sensing passage 63 chatters. Since it is located at, the damping effect of the air column vibration S becomes large, and the air column vibration S can be significantly damped. As a result, the pressure fluctuation in the diaphragm chamber 62b is suppressed, and the valve body 62c
Chattering is suppressed. Therefore, the pulsating noise transmitted to the air cleaner 23 side is reduced, and the abnormal noise in the vehicle interior due to chattering is reduced.

Further, in the case of the present embodiment, since the air bypass passage 61 is not throttled by the throttle portion as in the first embodiment, the supercharged air flowing through the air bypass passage 61 is not reduced and the deceleration time is reduced. The effect of reducing the pulsating sound of is enhanced. As described above, in this embodiment, the air bypass passage 61 is the same as the conventional one, so that a sufficient air bypass flow rate can be secured.

In the above embodiments, the two-way twin turbo engine in which two turbochargers are provided for one engine has been described. However, an engine in which one turbocharger is provided for one engine Of course, it is also applicable to.

[0039]

According to the present invention, the following effects can be obtained. (A) In the deceleration air bypass valve device for an engine with a supercharger according to claim 1, the hole diameter of the valve seat on which the valve body of the air bypass valve is seated is located immediately downstream of the air bypass valve in the air bypass passage. Since the first throttling portion having a diameter is provided, the throttling effect of the flow of the supercharged air flowing out from the air bypass valve can be enhanced and the pulsation damping effect can be increased. Therefore, it is possible to reduce the transmission of the pulsating sound to the air cleaner side due to the chattering of the valve element, and it is possible to reduce the generation of the abnormal noise due to the chattering of the valve element.

(B) In the deceleration air bypass valve device for an engine with a supercharger according to a second aspect, the valve body of the air bypass valve is provided in the sensing passage for introducing negative pressure or supercharging pressure into the diaphragm chamber of the air bypass valve. Since the second throttle portion located at the antinode portion of the air column vibration generated during chattering is provided, the air column vibration in the sensing passage can be significantly attenuated, and the pressure fluctuation in the diaphragm chamber can be suppressed. .. Therefore, chattering of the valve element can be suppressed, and the occurrence of abnormal noise can be reduced by reducing the pulsating noise transmitted to the air cleaner side.

[Brief description of drawings]

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

FIG. 2 is a system diagram of an engine with a supercharger including the device of FIG.

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

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

5 is an enlarged cross-sectional view of a second throttle unit in FIG.

FIG. 6 is a vibration of the air column in the sensing passage of FIG.
FIG. 6 is a cross-sectional view showing the positional relationship with the narrowed portion.

FIG. 7 is a schematic configuration diagram of a conventional deceleration air bypass valve 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 62b Diaphragm chamber 62c Valve body 62d Valve seat 63 Sensing passage 71 First throttle portion 75 Second throttle portion S Air column Vibration S ₁ Belly of air column vibration

Claims (2)

[Claims] 1. An upstream side and a downstream side of a compressor of a turbocharger are communicably connected to each other via an air bypass passage, a diaphragm type air bypass valve is provided in the air bypass passage, and the air bypass valve is provided in the diaphragm chamber. In the deceleration air bypass valve device of the engine with a supercharger, which is configured to be opened by a negative pressure introduced into the diaphragm chamber and closed by a supercharging pressure introduced into the diaphragm chamber, A deceleration air bypass valve device for a supercharged engine, wherein a first throttle portion having a diameter smaller than a hole diameter of a valve seat on which a valve body of an air bypass valve is seated is provided immediately downstream. 2. An upstream side and a downstream side of a compressor of a turbocharger are communicably connected via an air bypass passage, and a diaphragm type air bypass valve is provided in the air bypass passage, and the air bypass valve is provided in the diaphragm chamber. In the deceleration air bypass valve device of the engine with a supercharger, which is configured so that the valve is opened by the negative pressure introduced into the diaphragm chamber and closed by the supercharging pressure introduced into the diaphragm chamber, the negative pressure inside the diaphragm chamber of the air bypass valve. Alternatively, the deceleration of the engine with a supercharger is characterized in that the sensing passage for guiding the supercharging pressure is provided with a second throttle portion located at the antinode of the air column vibration that occurs when the valve body of the air bypass valve chatters. Air bypass valve device.