JPH01315613A - Supercharging pressure control valve device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the opening ability of a valve in a device where a diaphragm type open/close valve provided with a pressure chamber into which a negative pressure of intake air is introduced is arranged on the way of a pressure reducing passage bypassing a supercharger, by providing a second pressure chamber into which the pressure of intake air at the upstreamside of a throttle valve is introduced. CONSTITUTION:A supercharging pressure control valve device 30 is arranged on the way of a pressure reducing passage 8 bypassing a supercharger 3 provided on an intake passage 2. The supercharging pressure control valve device 30 is composed by coupling through a rod 24, a valve 25 detachably contacted to a valve seat 15, to a diaphragm 17 vertically displaced against a spring 28 according to a negative pressure of intake air at the downstream side of a throttle valve 6, which air is introduced in a first pressure chamber 19. A second pressure chamber 33 is additionally formed being defined by the diaphragm 17, a housing 31 and a bearing holder 27, and the pressure of intake air at the upstream side of the throttle valve 6 is introduced to the chamber 33 through a passage 32. A throttle 34 as a ventilation resistance is arranged in the passage 32.

Description

[Detailed Description of the Invention] [Industrial Application Field J] This invention relates to a boost pressure control valve device for a supercharged internal combustion engine, and in particular to suppressing abnormal external pressure in the intake passage upstream of the slot μ° valve that occurs during deceleration. The present invention relates to a boost pressure control valve device for an internal combustion engine.

[Conventional technology]

Conventional internal combustion engine with supercharger, for example, JP-A-61-1875
In the ones described in Publication No. 32, etc., a supercharging pressure control valve called QUEST GATE PAP is used.)
When the supercharging pressure becomes abnormally high, part of the exhaust gas supplied to the supercharger is detoured to weaken the operation of the supercharger.

However, if the turbocharger suddenly shifts to deceleration operation while the turbocharger is operating and the throttle valve suddenly closes, the boost pressure in the intake passage between the turbocharger and the slot)/& valve will suddenly increase. It is known that this can lead to dangerous situations.

FIG. 2 is a sectional view showing a conventional control valve device for a supercharged internal combustion engine that has been proposed against the above background. In the figure, (1) is the air cleaner which becomes the air intake part, (
2) is an intake pipe that serves as a passage for the intake air (hereinafter referred to as intake) from the air cleaner (1), (3) is a supercharger installed in the intake pipe], and (4) is the intake pipe C). Supercharger (3)
(5) is the second intake passage which also indicates the downstream side, (6) is the throttle valve that controls the intake air amount, and (7) is the throttle valve ((7) of the intake pipe (2). 6) is the third intake passage showing the downstream side of the intake passage, (8) is the pressure reduction passage which communicates the first and intake passages, and (9) is the second intake passage (5) which controls the opening and closing of the pressure reduction passage (8). ) is a boost pressure control valve device that controls the boost pressure of (1).
0) is a cylindrical housing, (11) is a housing (1
0) is an air hole penetrating the wall, (12) is the housing (
10) is formed at the top end of the housing (10) and prevents the diaphragm from reversing as will be described later; (13) is the housing (10);
The lower end of the flange is attached to an opening (14) formed in the intake pipe (2) constituting the second intake path (5). (15) is a valve seat showing the vicinity of the opening at the upper end of the inner circumferential side of the flange (14), (16) is a nip that serves as an inlet/outlet for intake air, and (17) is a bottomed edge of the top edge of the housing (10). A disk-shaped diaphragm (19) is a first pressure chamber formed by the diaphragm (17) and the case (18). , (20) converts the pressure in the third intake path (7) into the first pressure chamber (
19).
(23a) and (23bJ are dish-shaped holders that respectively hold the center part of the diaphragm (17), and (24) is a holder at the negative end. (23a) The rod (25) is attached to the center of (23b), and the rod (25) is attached to the other end of the rod (24) and is provided so as to come into contact with the valve seat (15). A disk-shaped valve that opens and closes, (26) is a bearing that slidably supports the rod (24), (27) is a bearing holder that holds the bearing (26), and (28) is a case (1).
8) and the holder (23a), and the suge ring (29) is an elastic member that biases the diaphragm 7 hum (17) in the valve closing direction.
27) is the atmospheric chamber.

The conventional boost pressure control valve device configured as described above operates as follows depending on the driving condition of the vehicle.

Operation during power idling and light load steady running In this case,
The throttle valve (6) is close to a fully closed state, and the supercharger (3) is also in a state where it is hardly producing any supercharging effect, so the pressure in the second intake passage (5) is almost atmospheric pressure, and the pressure in the third intake passage (5) is almost atmospheric pressure. The pressure in the intake passage (7) is in a high negative pressure state.

Therefore, since the high negative pressure in the third intake passage (7) is applied from the pressure number (21) to the first pressure chamber (19), the valve (25) is in an open state. However, due to the non-supercharging condition, the decompression passage (8) is simply a part of the intake air passage.

(b) Operation during medium and high load operation (acceleration near full throttle) In this case, the throttle valve (6) is close to the fully open state, and the supercharging effect of the supercharger (3) causes the second and third intake Road (5)
(7) are both in a high positive pressure state, the first pressure tiger (19)
Since the same positive pressure is applied inside the diaphragm (17
) is biased by the spring (28) in the direction of closing the valve (25), and the valve (25) is in a completely closed state.

In addition, the periphery of the diaphragm (17) is connected to the housing (1).
0), it is in close contact with the reversal prevention part (12) and receives a tensile force in the valve closing direction.

ri) Operation from medium load supercharging operation state to deceleration operation The above (
When the throttle valve (6) suddenly closes (decelerates) under the operating condition described in item (a), the supercharging pressure in the second intake passage (5) becomes abnormal external pressure, and conversely, the pressure in the third intake passage ('7) increases. changes to high negative pressure. Therefore, the pressure of the third intake passage (7) is applied to the first pressure chamber (19), the diaphragm (17) generates a force in the valve opening direction, and the valve (25) is also applied to the second intake passage (5). A force in the valve opening direction is generated in response to the high positive pressure, and the resultant force of both causes the valve (25) to open against the biasing force of the spring (28).

) Operation during slow acceleration when the throttle valve is at an intermediate opening In this case, the supercharging effect of the supercharger (3) is also lacking to some extent, and the supercharging pressure in the second intake passage (5) becomes positive pressure. However, since the throttle valve (6) is in the intermediate opening state, the third intake passage (
The pressure in 7) (that is, the pressure in the first pressure chamber (19)) is only about atmospheric pressure.

In such a pressure state, the lower surface of the valve (25) receives positive pressure (supercharging pressure) and generates a force in the valve opening direction, but the valve is closed only by the biasing force K of the spring (28). The state must be maintained.

[Issue Ml to be Solved by the Invention In recent vehicles in which the supercharging pressure setting of the vehicle is changing to a high pressure value, the pressing force in the valve opening direction acting on the lower surface of the valve (25) also increases. In addition, when it comes to large-displacement vehicles, a large-diameter valve (25
)Is required. As the supercharging pressure increases and the diameter of the valve (25) increases, the force Yv that presses the valve (25) in the opening direction during supercharging operation also increases due to the relationship shown in the following equation, Therefore, it is necessary to increase the force of the spring that biases the valve (25) in the valve-closing direction.

Fv=AvXCP1tPlz)
- (1) However, Fv two valves (25) lower surface pressing force A v: ff (25) lower surface receiving pressure m product Plr: pressure of second intake path (25) P12: pressure of pressure reducing path (8) Pl2: 8: However, when the atmospheric pressure is increased, it becomes necessary to increase the diaphragm opening force LD expressed by the following equation in order to fully rotate the valve (25) during normal operation (when the vehicle is decelerating).

E'D=AOX(Po-Pt6)
-cz) However, FD: Diaphragm (17) valve opening force AD: Diaphragm (17) effective area Psa: Pressure of the third intake passage (7) Po: atmospheric pressure Diaphragm valve opening force FD is shown in equation (2) From the relationship, in order to increase the generated force r,), in the conventionally structured supercharging pressure control valve device, it is necessary to expand the diaphragm effective area AD, and as a result, the supercharging pressure control valve device itself becomes larger. There was a problem with it being put away.

In addition, at the same time as the valve (25) opens and the supercharging air leaks into the pressure reducing path (8), the supercharging pressure suddenly changes, and at this moment, the pressure applied to the lower surface of the diaphragm (17) also suddenly changes at the same time. However, the valve (25) closes, and when the valve closes, the pressure of the supercharging air rises again and the valve (25) reopens.The valve (25) repeats the closing operation in high-speed synchronization. Due to the back movement, it enters a self-excited vibration state), and abnormal noise is generated,
There was also the problem that control became unstable.

This invention was made in order to solve the above-mentioned problems, and its object is to provide a supercharging pressure control valve device for an internal combustion engine that is compact and capable of stable control operations.

[Means for Solving the Problems J The supercharging pressure control valve device for an internal combustion engine according to the present invention has a second air intake passage between a supercharger and a throttle valve that communicates with the second intake passage through a second passage that guides the pressure. A second pressure chamber is provided, and a restriction is further provided in the second passage.

[Operation J] In this invention, the second pressure chamber generates a pressing force on the diaphragm, thereby improving the valve opening force of the valve, and t! The throttle provided in the c2 passage gives a time delay to the speed of pressure transmission through the second passage, thereby suppressing self-excited vibration of the valve and ensuring stable control operation.

〔Example" Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the same reference numerals as in FIG. 2, which shows a conventional device, indicate the same or corresponding parts. (30) corresponds to the boost pressure control valve device in this embodiment, and (31) corresponds to the housing (10) in Fig. 2, but the reversal prevention part (12) in Fig. 2 has been removed. Second, a second passageway (32) is formed which goes back to the wall and guides the pressure of the second intake passageway (5). (33) is a second pressure chamber formed between the diaphragm (17), the housing (31) and the bearing small diameter (27), and communicated with the second intake passage (5) through a second passage (32). , (34) are provided in the second passage (32) and serve as ventilation resistance to give a time delay to the speed of pressure transmission through the second passage (32).

This embodiment is constructed as described above, and has a first pressure chamber (19
) and the second pressure chamber (33), the opening force of the valve (25) due to the pressure received by the valve (25), and the closing force due to the elastic force of the spring (28). ) is closed.

The first pressure chamber (19) and the second pressure chamber (
33), that is, the force due to the differential pressure between the diaphragm (17
) is a force 1' in the opening direction of the valve (25) due to the pressure received by the valve (25).

(Diaphragm opening force) is expressed by the following equation.

]'D-ADX (Pl) -pHl)
°=(3) However, AD: Effective area of diaphragm (17) P1 = 2nd
Pressure PI3 in the intake passage (5): Pressure in the third intake passage (7) Here, the diaphragm generated force in the conventional device shown in FIG. 2 will be compared with the diaphragm generated force in this embodiment. The table below was obtained based on experiments under appropriate conditions, and shows the maximum differential pressure during deceleration in equations (2) and (3).

However, pressure indicates absolute pressure.

Based on the values shown in the above table, if the diaphragm generated force FD in the conventional device shown in FIG. 2 and this embodiment are the same, the relationships expressed by equations (2) and (3) can be obtained.

(Diaphragm effective area 1An according to the example) 0.7" 1.6X (Diaphragm effective area A according to the conventional device)
D) ... (4) Therefore, according to equation (4), in order to obtain the same diaphragm generated force]i'1), in this embodiment, the conventional diaphragm effective area AD is 0.7/1.6 However, since a diaphragm with a small effective area can be used for the conventional housing (3
1) The outer diameter of the control valve system r can be made smaller.
The entire R(30) can be designed to be compact. Also,
During sudden deceleration from supercharging operation, 'JIII pressure chamber (1
9) has a high negative pressure equivalent to that during idling, and the second pressure chamber (33) has a higher external pressure than during supercharging operation, resulting in a high positive pressure, so the pressure received by the diaphragm (17) increases instantly. ), the response is better than before.

Additionally, the supercharging pressure in the second intake passage (5) changes suddenly at the same time as the valve opens, but the pressure is transmitted by the restrictor 9 (34) provided in the second passage (32) to the second pressure chamber (33). A time delay K occurs, thereby preventing the pressure in the second pressure chamber (33) on the lower surface of the diaphragm (17) from changing suddenly in synchronization. Therefore, the high positive pressure applied during supercharging operation is
It does not change suddenly when the valve is opened, but changes over time.

Note that the inner diameter of the throttle (34) is set to a predetermined value that does not cause self-oscillation η, depending on the volume of the second pressure chamber (33).

As described above, the response when the valve is opened is extremely fast, and after the valve is opened, stable control is possible that is not affected by sudden changes in the supercharging pressure of the controlled fluid.

The table below shows the relationship between the pressures applied to the upper and lower surfaces of the diaphragm (17) in this example, and the pressure applied to the diaphragm (17).
7), the presence or absence of the reversal phenomenon at the peripheral edge is compared with the conventional device shown in FIG. 2, assuming that there is no reversal prevention part (12).

As shown in Table 2, in the conventional device shown in FIG. 2, if the reversal prevention part (12) is not provided, the dial
A reversal phenomenon of the hum (17) is common, and a reversal phenomenon may occur even during steady running. If this reversal phenomenon occurs frequently, the deterioration of the diaphragm (17) progresses, so in reality, a reversal prevention part (12) is provided to prevent reversal, but the reversal prevention part (12) and the diaphragm (17)
Another problem arises: wear of the diaphragm (17) due to friction with the diaphragm (17). On the other hand, in this embodiment, by providing the second pressure chamber (33), as shown in Table 2, the first pressure chamber (19) has negative pressure during idling (e.g. atmospheric pressure - approx. 500 m h) to the thrower) A/The supercharging pressure when the valve (6) is fully open (e.g. atmospheric pressure + approx. 650 mph)
Pressure up to MHg) is applied), second pressure chamber (33)
Since the pressure from the atmospheric pressure at idling to the highest set boost pressure (for example, atmospheric pressure + 700 ta Hg) is applied to the engine, the pressure in the first pressure chamber (19) is always higher than the pressure in the second pressure chamber (33). is larger. Therefore, regardless of the operating state, the diaphragm (17) does not reverse, so the reversal prevention part (12) as shown in FIG.
Therefore, there is no need for the above-mentioned problem due to friction between the reversal prevention part (12) and the diaphragm (17).

[Effects of the Invention] As explained above, according to the present invention, a second pressure chamber is provided in the second intake passage between the supercharger and the throttle valve, and the second pressure chamber communicates with the second passage for guiding the pressure thereof. In addition, by providing a restrictor in the second passage, the device can be made more compact by improving the opening force of the valve, and by suppressing self-excited vibration of the valve, stable control operation can be achieved. It is something.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional device. In the figure, (3) is the supercharger, (4) is the first intake path, and (5) is the first intake path.
) is the second intake path, (6) is the thrower) A/valve, (7) is the third intake path, (8) is the pressure reduction path, (17) is the diaphragm,
(19) is the first pressure chamber, (20) is the first passage, (25)
(28) is a spring, (30) is a supercharging pressure control valve device for an internal combustion engine, (32) is a second passage, (33) is a second
The pressure chamber (34) is a diaphragm. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A valve that opens and closes a pressure reducing passage that communicates a first intake passage on the upstream side of the supercharger and a second intake passage between the supercharger and the throttle valve, and a third intake passage on the downstream side of the slot valve. a first pressure chamber communicated with a first passage leading to the pressure, a second pressure chamber communicating with the second passage leading the pressure to the second intake passage, and partitioning the first and second pressure chambers. A supercharging pressure control valve device for an internal combustion engine, comprising a diaphragm connected to the valve, a throttle provided in the second passage, and an elastic member that biases the diaphragm in the closing direction of the valve.