JP2004084664A - Negative pressure supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply stable negative pressure and reduce influence to an engine intake control in a negative pressure supply device utilizing an ejector. <P>SOLUTION: An inlet port 24 of the ejector 24 is connected to the downstream part of a turbocharger 8 of an intake pipe 5 through a control valve 17. An outlet port 26 is connected to a downstream part of the throttle valve 6 and a suction port 27 is connected to a pneumatic pressure booster 3 through a check valve 19. A downstream part of the throttle valve 6 of the intake pipe 5 is connected to the pneumatic pressure booster 3 through the check valves 18, 19. The control valve 17 is opened and closed by the differential pressure between the negative pressure of the pneumatic pressure booster 3 and atmospheric pressure, and the ejector 16 is operated only when the negative pressure comes short. The influence to the engine intake control is reduced by lowering the frequency of bypassing the throttle valve 6 with the ejector 16. Pressure loss due to the control valve 17 is reduced by providing the control valve 17 on the inlet port 24 side of the ejector 16. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a negative pressure supply device for supplying a negative pressure to a negative pressure operating device such as a pneumatic booster using an ejector by using a pressure of an intake pipe of an engine as a pressure source.
[0002]
[Prior art]
2. Description of the Related Art Generally, a pneumatic booster is provided in a vehicle braking device to increase a braking force. This pneumatic booster utilizes the engine's intake negative pressure as a negative pressure source, and introduces the intake negative pressure into a constant-pressure chamber (negative pressure chamber), and applies a differential pressure from the atmospheric pressure to the power piston. A thrust is generated to assist the operating force of the braking device.
[0003]
Further, there is known a technique for increasing the degree of vacuum of a negative pressure supplied to a pneumatic booster using an ejector. The ejector has a diffuser arranged downstream of the nozzle and a negative pressure outlet between them.When gas flows from the nozzle side to the diffuser side, a high-speed jet is generated, and the negative pressure outlet is generated. A negative pressure with a high degree of vacuum can be generated.
[0004]
As a negative pressure supply device that supplies a negative pressure to a pneumatic booster using an ejector, for example, an ejector is arranged in parallel with a throttle valve so that the amount of air supplied to the ejector during no-load operation can be adjusted. (See Patent Document 1), and an ejector in which an intake pipe is arranged in parallel with a throttle valve, that is, an intake pipe is bypassed between a downstream side of the throttle valve and an air cleaner, is attached to the outside of the pneumatic booster. (See Patent Document 2).
[Patent Document 1]
JP-A-54-13814 [Patent Document 2]
JP-A-60-29366 [0005]
[Problems to be solved by the invention]
On the other hand, conventionally, in order to obtain a high output with a small engine, a supercharger such as a turbocharger has been widely used. In an engine equipped with a supercharger, since the intake air is pressurized by the supercharger, the degree of vacuum of the intake pipe negative pressure is reduced, and a sufficient negative pressure may not be obtained. In particular, in the technique disclosed in Patent Document 2, a situation may occur in which positive pressure is supplied to the ejector from the downstream side of the throttle valve, and no negative pressure is generated by the ejector.
[0006]
Also, when trying to use a negative pressure supply device using an ejector, since the ejector is arranged bypassing the throttle valve, when the ejector operates, air flowing through the ejector in addition to air passing through the throttle valve is added, As a result, the amount of air introduced into the combustion chamber of the engine increases, so that the intake control of the engine becomes unstable. In particular, during idling when the intake air amount is small, the effect of the bypass flow rate by the ejector becomes large, causing a problem.
[0007]
The present invention has been made in view of the above points, and enables a sufficient negative pressure to be obtained even in an engine equipped with a supercharger. It is another object of the present invention to provide a negative pressure supply device capable of supplying a stable negative pressure and reducing the influence on the intake control of the engine.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a negative pressure supply device including an ejector that supplies a negative pressure from a suction port to a negative pressure operating device by flowing a fluid from an inlet to an outlet. Connecting an inlet of the ejector between the supercharger and a fluid resistor provided downstream of the supercharger in an intake pipe of an engine having a supercharger, and connecting an outlet of the ejector to the A non-return valve connected between the flow resistor in the intake pipe and the intake port of the engine, and allowing the suction port of the ejector to only allow the flow of fluid from the negative pressure differential device side to the suction port side of the ejector; Connected to the negative pressure operating device through a valve, and the upstream portion of the intake port through a check valve that allows only the flow of fluid from the negative pressure differential device side to the upstream portion side of the intake port. Note that the connection to the negative pressure To.
[0009]
With this configuration, even if the intake air is pressurized by the supercharger, the ejector operates by the differential pressure between the downstream portion of the supercharger and the upstream portion of the intake port, so that a sufficient negative pressure is generated. Can be done.
[0010]
A negative pressure supply device according to a second aspect of the present invention is the negative pressure supply device according to the first aspect, wherein the flow resistor is a throttle valve.
[0011]
According to a third aspect of the present invention, in the negative pressure supply device according to the first aspect, the negative pressure supply from the suction port of the ejector is controlled by a differential pressure between the negative pressure of the negative pressure operating device and the atmospheric pressure. A control valve is provided, and the control valve closes when the stored negative pressure of the negative pressure operating device exceeds a predetermined value, and opens when the stored negative pressure of the negative pressure operating device is equal to or lower than a predetermined value. It is characterized by a valve.
[0012]
With this configuration, when the negative pressure of the negative pressure operating device exceeds a predetermined value and is sufficient, the control valve closes, the ejector stops, and the negative pressure of the intake pipe operates the check valve. When the negative pressure is lower than a predetermined value and the pressure is insufficient, the control valve is opened, the ejector is operated, and the negative pressure of the suction port of the ejector is reduced through the check valve. Supplied to a pressure actuator.
[0013]
According to a fourth aspect of the present invention, in the negative pressure supply device according to the third aspect, the control valve is driven by a differential pressure between a negative pressure of the negative pressure operating device and an atmospheric pressure. .
[0014]
According to a fifth aspect of the present invention, in the negative pressure supply device according to the third aspect, the control valve controls a negative pressure supply from a suction port of the ejector by opening and closing an inlet side of the ejector. It is characterized.
[0015]
With this configuration, since the control valve is disposed on the inlet side of the ejector, the decrease in the negative pressure generating force of the ejector due to the pressure loss of the control valve is reduced.
[0016]
In the negative pressure supply device according to a sixth aspect of the present invention, in the configuration of the third aspect, the control valve causes a flow from a downstream side of the supercharger to an inlet side of the ejector to act in a valve closing direction. It is characterized by the following.
[0017]
With this configuration, the valve element rapidly moves when the control valve starts opening and when the control valve closes due to the pressure acting on the valve element of the control valve.
[0018]
A negative pressure supply device according to a seventh aspect of the present invention is the negative pressure supply device according to any one of the first to sixth aspects, wherein the intercooler and the fluid resistor in the intake pipe provided with an intercooler downstream of the supercharger. And an inlet of the ejector is connected between the ejector and the ejector.
[0019]
With this configuration, the air cooled by the intercooler flows through the ejector.
[0020]
According to an eighth aspect of the present invention, there is provided a negative pressure supply device according to any one of the first to sixth aspects, further comprising a check valve for releasing the pressure on the outlet side of the ejector to the atmosphere.
[0021]
With this configuration, even when a high positive pressure is generated at the intake pipe connection portion on the inlet side and the outlet side of the ejector by the supercharger, the outlet side of the ejector is opened to the atmosphere and the fluid flows into the ejector. Become like
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a circuit diagram of an intake / exhaust device 2 and a pneumatic booster 3 (negative pressure operating device) of an engine to which a negative pressure supply device 1 according to a first embodiment of the present invention is connected.
[0023]
As shown in FIG. 1, a compressor C of a throttle valve 6 (flow resistor), an intercooler 7, and a compressor C of a turbocharger 8 (supercharger) and an air filter are arranged in the intake pipe 5 of the engine body 4 in order from the engine body 4 side. 9 is disposed, and the air filter 9 is open to the atmosphere. Further, a turbine T of the turbocharger 8, a catalytic converter 11, and a muffler 12 are arranged in the exhaust pipe 10 of the engine body 2 in order from the engine body 4, and the muffler 12 is open to the atmosphere. The negative pressure supply device 1 has an inlet port 13, an outlet port 14, and a suction port 15. The inlet port 13 is located downstream of the turbocharger 8 of the intake pipe 5, that is, between the compressor C and the intercooler 7. The outlet port 14 is connected to a downstream portion of the throttle valve 6 of the intake pipe 5, that is, an upstream portion of the intake port of the engine body 4, and the suction port 15 is connected to a constant pressure of the pneumatic booster 3. Chamber (negative pressure chamber).
[0024]
Although not shown here, the pneumatic booster 3 includes a negative pressure chamber (constant pressure chamber) defined by a power piston and a variable pressure chamber, and an input to an input rod connected to a brake pedal or the like ( In response to the driver's braking force), the atmosphere is introduced into the variable pressure chamber, and a thrust is generated in the power piston by the differential pressure generated between the negative pressure chamber and the variable pressure chamber, thereby applying a servo force to the brake operating force. It is general.
[0025]
The negative pressure supply device 1 includes an ejector 16, a control valve 17, and two check valves 18 and 19. As shown in FIG. 6, the ejector 16 has a diffuser 21 disposed downstream of the nozzle 20, and a negative pressure outlet 22 is opened between the diffuser 21 and the gas ejected from the nozzle 20 to the diffuser 21. When flowing, a high-speed jet is generated in the throat portion 23 of the nozzle 20, and a negative pressure having a high degree of vacuum can be generated in the negative pressure outlet 22. The inlet 24 of the nozzle 20 of the ejector 16 is connected to a port 25 of the control valve 17 described later, the outlet 26 of the diffuser 21 is connected to the outlet port 14, and the suction port 27 of the negative pressure outlet 22 is connected in reverse. It is connected to the suction port 15 via a stop valve 19. The check valve 19 allows only the flow from the suction port 15 side to the suction port 27 side.
[0026]
The control valve 17 includes an on-off valve 29 that opens and closes a port 28 communicating with the inlet port 13 and a port 25 that communicates with the inlet 24 of the ejector 16, and an actuator 30 that controls opening and closing of the on-off valve 29. I have. The actuator 30 is operated by a pressure difference between a pressure in a constant pressure chamber (negative pressure chamber) of the pneumatic booster 3 introduced through the passage 31 from the suction port 15 and the atmospheric pressure, and the degree of vacuum in the constant pressure chamber is sufficient. When the pressure is high (when the storage negative pressure in the constant pressure chamber exceeds a predetermined value), the on-off valve 29 is closed, and when the degree of vacuum in the constant pressure chamber drops to a predetermined value due to insufficient vacuum (the storage negative pressure in the constant pressure chamber becomes low). When it is equal to or less than a predetermined value, the on-off valve 29 is opened.
The predetermined values of the opening and closing of the on-off valve 29 may be made different by providing hysteresis between the opening and closing of the valve.
[0027]
The outlet port 14 bypasses the ejector 16 by a check valve 18 and is connected to the suction port 15 via a check valve 19. The check valve 18 allows only the flow from the suction port 15 side to the outlet port 14 side.
[0028]
Next, a specific configuration of the negative pressure supply device 1 will be described with reference to FIGS. Note that parts corresponding to the respective parts in FIG.
As shown in FIGS. 2 and 3, in the negative pressure supply device 1, an ejector 16, a control valve 17, and check valves 18 and 19 are integrally provided in a case 32. A flat ejector 16 is formed on an upper portion of the case 32. The ejector 16 includes a nozzle 20, a diffuser 21, and a negative pressure outlet 22 opened on both sides between them. The nozzle 20 and the diffuser 21 constitute a single Laval nozzle having a smoothly reduced inlet and an enlarged outlet having a gentle divergence angle (about 5 to 10 °) downstream from the throat portion 23 of the nozzle 20. I have. The negative pressure outlet 22 is disposed downstream from the throat portion 23 of the nozzle 20 by a distance approximately two to three times the width of the throat portion 23.
[0029]
The inlet 24 of the nozzle 20 communicates with an inlet port 13 extending horizontally below the nozzle 20, and the outlet 26 of the diffuser 21 communicates with an outlet port 14 extending horizontally below the diffuser 21. A control valve 17 is arranged below the inlet 24 of the ejector 16, and check valves 18 and 19 are arranged in series below the outlet 26. The suction port 27 of the ejector 16 is communicated with a passage 33 extending to below the outlet 26. The outlet 26 communicates with the passage 33 through the check valve 18, and the passage 33 communicates with the suction port 15 extending downward through the check valve 19. The check valve 18 allows only the flow from the passage 33 side to the outlet 26 side, and the check valve 19 allows only the flow from the suction port 15 side to the passage 33 side.
[0030]
The control valve 17 includes an on-off valve 29 for opening and closing between the inlet 24 and the inlet port 13, and an actuator 30 for opening and closing the on-off valve 29. The on-off valve 29 is a poppet valve, and a valve body 34 is seated on a valve seat 35 formed on the downstream side inlet 24 side, and the differential pressure between the upstream side inlet port 13 and the downstream side inlet 24 is closed. It works in the direction. The actuator 30 divides the inside of the pressure chamber 36 into a negative pressure chamber 39 and an atmosphere chamber 40 by a diaphragm 37 and a piston 38, communicates the negative pressure chamber 39 with the suction port 15 through a passage 41, and passes through the atmosphere chamber 40. It is open to the atmosphere through pores 42. The valve body 34 and the piston 38 are connected to each other by a connecting rod 43. The connecting rod 43 is guided by a seal 44, and the seal 44 seals between the inlet port 13 and the pressure chamber 36. The piston 38 and the connecting rod 43 are connected so as to be relatively movable in the axial direction by a predetermined distance. The valve body 34 is urged by a spring 45 in the valve closing direction, and the piston 38 is urged by a spring 46 in the valve opening direction of the valve body 34.
[0031]
The actuator 30 is operated by a pressure difference between the negative pressure chamber 39 and the atmosphere chamber 40. When the degree of vacuum in the negative pressure chamber 39 is sufficiently high, the on-off valve 29 is closed via the connecting rod 43 and the negative pressure chamber 39 is closed. When the degree of vacuum is insufficient and drops to a predetermined value, the on-off valve 29 is opened.
[0032]
Next, the operation of the present embodiment configured as described above will be described.
The air sucked from the air filter 9 is pressurized by the compressor C of the turbocharger 8, cooled by the intercooler 7, and then supplied to the intake manifold of the engine body 4 with the flow rate controlled by the throttle valve 6. . The exhaust gas discharged from the exhaust manifold of the engine body 4 drives the turbine T of the turbocharger 8, is purified by the catalytic converter 11, and is discharged to the atmosphere via the muffler 12. In the turbocharger 8, the compressor C is driven by the turbine T driven by the exhaust gas to pressurize the intake air, so that the efficiency of charging the intake air into the combustion chamber can be increased, and a high output can be obtained. it can.
[0033]
In the negative pressure supply device 1, when the degree of vacuum in the constant pressure chamber of the pneumatic booster 3 is sufficiently high, the actuator 30 closes the on-off valve 29 due to the differential pressure between the negative pressure in the constant pressure chamber and the atmospheric pressure, and ejects the ejector. Sixteen inlets 24 are closed. In this state, the negative pressure on the downstream side of the throttle valve 6 of the intake pipe 5 is directly supplied to the constant pressure chamber of the pneumatic booster 3 via the check valves 18 and 19.
[0034]
When the degree of vacuum in the constant pressure chamber of the pneumatic booster 3 decreases, the differential pressure between the negative pressure chamber 39 of the actuator 30 and the atmosphere chamber 40 decreases, the on-off valve 29 opens, and the inlet port 13 and the inlet of the ejector 16 enter. 24 is communicated. In this state, the ejector 16 is actuated by a pressure difference between the downstream side of the turbocharger 8 of the intake pipe 5 and the downstream side of the throttle valve 6, and the pneumatic pressure is supplied from the suction port 27 of the ejector 16 through the check valve 19. A negative pressure is supplied to the constant pressure chamber of the booster 3. In this case, even if the pressure on the downstream side of the turbocharger 8 increases due to the supercharging pressure, the ejector 16 operates by the differential pressure between the pressure and the downstream side of the throttle valve 6, so that a sufficient negative pressure is generated. Can be.
[0035]
In this way, normally, the negative pressure is directly supplied from the intake pipe 5 to the pneumatic booster 3, and when the negative pressure of the pneumatic booster 3 is insufficient, the ejector 16 is operated to operate the pneumatic booster. Since a negative pressure of a high degree of vacuum is supplied to the power unit 3, a sufficient negative pressure can be maintained at all times in the pneumatic booster 3, and the amount of intake air bypassing the throttle valve 6 by the ejector 16 can be sufficiently increased. Therefore, the influence on the intake control of the engine can be minimized.
[0036]
By arranging the control valve 17 on the inlet 24 side of the ejector 16, it is possible to reduce the influence of pressure loss near the valve closing position of the control valve 17 as compared with the case where the control valve 17 is arranged on the outlet 26 side. A negative pressure can be supplied. For example, when the pressure at the inlet 24 is atmospheric pressure and the pressure at the outlet 26 is -200 mmHg, a negative pressure of about -400 mmHg can be obtained at the suction port 27. Here, when the control valve 17 is arranged on the outlet 26 side, assuming that the pressure loss of the control valve 17 is 20 mmHg, the pressure a on the inlet 24 side remains the atmospheric pressure, and the pressure b on the outlet 26 side becomes -180 mmHg, The negative pressure (ca) obtained at the suction port 27 is about -360 mmHg. On the other hand, when the control valve 17 is disposed on the inlet 24 side, the pressure a on the inlet 24 side becomes −20 mmHg, the pressure b on the outlet 26 side becomes −200 mmHg, and the negative pressure (c− a) is about -380 mmHg, so that a larger negative pressure can be obtained than when it is arranged on the outlet side. FIG. 7 shows the relationship between the operating differential pressure of the ejector 16 and the suction port pressure.
[0037]
The pressure on the inlet 24 side of the ejector 16 is higher than that on the outlet 26 side, the volume flow rate is small, and the flow velocity is also small. Since the pressure loss caused by the control valve 17 is proportional to the square of the flow velocity, the pressure loss can be reduced by arranging the control valve 17 on the inlet 24 side as compared with the case where the control valve 17 is arranged on the outlet 26 side. .
[0038]
Since the differential pressure between the inlet port 13 on the upstream side and the inlet 24 on the downstream side acts on the valve body 34 in the valve closing direction of the control valve 17, when the valve opening starts and the valve closing ends, the valve body 34 It moves rapidly, and the piston 38 and the connecting rod 43 can move relative to each other in the axial direction, and there is a sliding resistance between the seal 44 and the connecting rod 43. Hysteresis occurs between the pressure in the constant pressure chamber of the type booster and the atmospheric pressure) and the operating pressure when the valve is opened. FIG. 8 shows the relationship between the operating differential pressure of the valve element 34 of the control valve 17 and the lift amount. As a result, the valve element 34 can be opened and closed quickly, and hunting near the set pressure of the control valve 17 can be prevented. Further, the relative movement of the connecting rod 43 and the piston 38 can absorb the inclination of the connecting rod 43 and the piston 38, and the valve body 34 can be reliably seated on the valve seat 35.
[0039]
By arranging the check valves 18 and 19 in series, it is possible to reduce the leakage of the check valves 18 and 19 and improve the negative pressure retention of the pneumatic booster 3 when the engine is stopped. Can be. On the other hand, by connecting the check valve 18 directly to the pneumatic booster 3, the pressure loss due to the check valves 18 and 19 at the time of supplying the negative pressure may be reduced.
[0040]
As shown in FIG. 2, since the ejector 16 is formed in a flat plate shape, a portion forming the ejector 16 and a portion accommodating the control valve 17 and the check valves 18 and 19 are separated from each other. They can be flat, and can be easily combined by welding or the like. As a result, the external force acting on the case 32 from the intake pipe 5 and the pneumatic booster 3 via the inlet port 13, the outlet port 14, and the suction port 15 is less likely to be transmitted to the ejector 16, so that the degree of freedom in designing the ejector 16 is improved. And the leakage of the welded portion can be prevented, and the durability can be improved.
[0041]
Next, a second embodiment of the negative pressure supply device according to the present invention will be described with reference to FIGS. It should be noted that, with respect to the above-described first embodiment, similar portions are denoted by the same reference numerals, and only different portions will be described in detail.
[0042]
In the negative pressure supply device 47 of the second embodiment, a flat ejector 16 is formed in a case 48, and the inlet port 13 and the outlet port 14 extend vertically from the inlet 24 and the outlet 26 of the ejector 16, respectively. A suction port 15 communicating with the two suction ports 27 via the check valve 19 is opened on the opposite surface. The case 48 is directly attached to the outside of an outer shell 49 (only a part is shown) of a constant pressure chamber of the pneumatic booster 3, and the suction port 15 is provided in the constant pressure chamber through a suction opening 50 formed in the outer shell 49. In direct communication.
[0043]
The control valve 17 has a valve element 34 disposed in the inlet port 13, a diaphragm 37 sandwiched between a case 48 and an outer shell 49, and a negative pressure chamber of the actuator 30 through an opening 51 of the outer shell 49 to control the pressure of the pneumatic booster. It is integrated with the room. The spring for urging the valve body 34 and the piston 38 is omitted, and these are urged by the elastic force of the diaphragm 37.
[0044]
The passage connecting the outlet port 14 and the suction port 15 and the check valve 18 provided in this passage are not provided in the case 48 but are separately provided outside.
[0045]
With this configuration, in addition to the operation and effect of the first embodiment, the height of the case 48 is reduced and the case 48 is integrated with the outer shell of the pneumatic booster 3 to save space. Can be.
[0046]
In the first and second embodiments, the outlet port 14 of each of the negative pressure supply devices 1 and 47 is connected to the downstream portion of the throttle valve 6 of the intake pipe 5, but the throttle valve 6 is not provided. In such a case (for example, when intake control is performed based on the valve lift and opening / closing timing), a flow resistor in place of the throttle valve 6 is provided between the turbocharger 8 and the intake port of the engine body 4. May be connected to a portion corresponding to an upstream portion of an intake port of the engine body 4 at a downstream portion of the engine body 4. In this case, as the flow resistor, a throttle portion or the like provided in the intake pipe can be used, but the present invention is not limited to this, and any other substance that provides flow resistance to the fluid flowing in the intake pipe may be used. You can also.
[0047]
Further, the control valve 17 is a mechanical type that moves the diaphragm 37 and the piston 38 by the differential pressure between the atmospheric pressure and the negative pressure chamber of the pneumatic booster, but is not limited thereto. An electromagnetic valve that detects the negative pressure chamber of the booster with a pressure sensor and controls opening and closing based on the detected value may be used.
[0048]
Further, in the first and second embodiments, the inlet port 13 is connected between the compressor C and the intercooler 7, but the downstream portion of the turbocharger 8 of the intake pipe 5 and the throttle valve 6 (flow resistor ) As long as it is connected to the upstream part.
For example, the inlet port 13 may be connected between the intercooler 7 and the throttle valve 6. When the ejector is connected between the intercooler 7 and the throttle valve 6 as described above, since the cooled air flows through the ejector, the heat-resistant temperature of the ejector can be set low, and the degree of freedom of the material of the ejector is reduced. Increase.
[0049]
In the first and second embodiments, the pneumatic booster 3 is connected to the outlet 26 of the diffuser 21 of the ejector 16 and the outlet port 14 to the downstream side of the throttle valve 6 of the intake pipe 5. The pneumatic booster 3 can be connected to any position as long as it is located upstream of the intake port of the engine body 4.
[0050]
In a vehicle equipped with a supercharger, the space between the downstream portion of the turbocharger 8 and the throttle valve 6, that is, the inlet side of the ejector 16, and the space between the throttle valve 6 and the intake port of the engine body 4 during vehicle acceleration, that is, A high positive pressure is generated at the outlet side of the ejector 16. Therefore, there is a possibility that the ejector 16 does not operate and no negative pressure is generated by the ejector 16.
[0051]
In such a case, as shown in FIG. 9, by providing a check valve 61 at the outlet side of the ejector 16 for releasing the fluid of the positive pressure to the atmosphere, a fluid flow occurs in the ejector 16 and the negative pressure is reduced. Then, a negative pressure can be supplied to the pneumatic booster 3.
[0052]
In the case of the above configuration, the throttle port 6 is provided with a throttle port to prevent the fluid sent from the throttle valve 6 to the intake port of the engine body 4 from flowing backward from the outlet port 14 and being discharged from the check valve 61. It is desirable to provide a check valve 62 that restricts the flow of fluid from the valve 6 to the check valve 61.
[0053]
【The invention's effect】
As described in detail above, according to the negative pressure supply device of the present invention, the ejector operates by the differential pressure between the downstream portion of the supercharger and the upstream portion of the intake port, so that a sufficient negative pressure can be generated. Can be.
[0054]
If the negative pressure supply device is provided with a control valve, if the negative pressure of the negative pressure operating device is sufficient, the control valve closes and the ejector stops, and the negative pressure of the intake pipe is reduced by a check valve. Is supplied directly to the negative pressure actuation device. When the negative pressure is insufficient, the control valve opens, the ejector operates, and the negative pressure at the suction port of the ejector is supplied to the negative pressure operating device via the check valve. At this time, by arranging the control valve on the inlet side of the ejector, it is possible to suppress a decrease in the negative pressure generating force of the ejector due to the pressure loss of the control valve. As a result, a sufficient negative pressure can always be maintained in the negative pressure operating device, and the influence of the operation of the ejector on the intake control of the engine can be minimized.
[0055]
Further, according to the negative pressure supply device according to the present invention, the valve body rapidly moves at the start of opening and at the end of closing of the control valve due to the pressure acting on the valve body of the control valve. Can be done quickly.
[Brief description of the drawings]
FIG. 1 is a block diagram of an engine and a pneumatic booster to which a negative pressure supply device according to a first embodiment of the present invention is applied.
FIG. 2 is a longitudinal sectional view of the negative pressure supply device according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line AA of FIG. 2;
FIG. 4 is a longitudinal sectional view of a negative pressure supply device according to a second embodiment of the present invention.
FIG. 5 is a transverse sectional view taken along line BB of FIG. 4;
FIG. 6 is an explanatory diagram showing a schematic configuration of an ejector used in the negative pressure supply device of the present invention.
FIG. 7 is a graph showing a relationship between a suction port pressure of an ejector and an operation differential pressure.
FIG. 8 is a graph showing a relationship between an operation differential pressure of a valve body of a control valve and a lift amount in the apparatus of FIG. 2;
FIG. 9 is a block diagram showing a modification of the apparatus of FIG.
[Explanation of symbols]
1. Negative pressure supply device 3. Pneumatic booster (negative pressure actuating device)
4 Engine body 5 Intake pipe 6 Throttle valve (flow resistor)
8 Turbocharger (supercharger)
16 Ejector 17 Control valve 18, 19 Check valve 24 Inlet 26 Outlet 27 Suction port

Claims (8)

A negative pressure supply device having an ejector for supplying a negative pressure from a suction port to a negative pressure operating device by flowing a fluid from an inlet to an outlet, wherein the supercharger is provided in an intake pipe of an engine having a supercharger. And an inlet of the ejector is connected between a fluid resistor provided downstream of the supercharger, and an outlet of the ejector is connected between the flow resistor in the intake pipe and an intake port of the engine. Connecting the suction port of the ejector to the negative pressure operating device via a check valve that allows only the flow of fluid from the negative pressure differential device side to the suction port side of the ejector; A negative pressure supply device, wherein an upstream portion is connected to the negative pressure operating device via a check valve that allows only fluid flow from the negative pressure differential device side to the upstream portion side of the intake port. The negative pressure supply device according to claim 1, wherein the flow resistor is a throttle valve. A control valve for controlling a negative pressure supply from a suction port of the ejector, wherein the control valve closes when a stored negative pressure of the negative pressure operating device exceeds a predetermined value; 2. The negative pressure supply device according to claim 1, wherein the valve is opened when the stored negative pressure is equal to or lower than a predetermined value. The negative pressure supply device according to claim 3, wherein the control valve is driven by a differential pressure between a negative pressure of the negative pressure operating device and an atmospheric pressure. The negative pressure supply device according to claim 3, wherein the control valve controls the supply of negative pressure from a suction port of the ejector by opening and closing an inlet side of the ejector. 4. The negative pressure supply device according to claim 3, wherein the control valve is configured such that a flow from a downstream side of the supercharger to an inlet side of the ejector acts in a valve closing direction. 5. The inlet of the ejector is connected between the intercooler and the fluid resistor in the intake pipe in which an intercooler is provided downstream of the supercharger. Negative pressure supply device. The negative pressure supply device according to any one of claims 1 to 6, further comprising a check valve for releasing a pressure at an outlet side of the ejector to the atmosphere.

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