JPS5950849A - Vacuum source for vehicle vacuum boosting device - Google Patents

Abstract

PURPOSE:To make it possible to obtain a predetermined boost ratio without making a vacuum boosting device large, by utilizing an air ejector to supply high vacuum to the vacuum boosting device. CONSTITUTION:An air ejector 10 having an air-intake port communicated with the atmosphere is connected to a vacuum extracting hole 8 arranged downstream of a throttle valve 7 in an internal combustion engine E, and a vacuum chamber 3 in a vacuum boosting device S is connected to a pressure reducing chamber 15 in the air ejector 10. Further, a first check valve 23 is disposed in a bypass passage 22 which bypasses the air ejector 10 and which has a flow resistance lower than that of the air ejector 10, and a second check valve 24 is disposed between the bypass passage 22 and the vacuum chamber 3. Accordingly, even if the intake vacuum pressure in the internal combustion engine is low, high vacuum may be fed to the vacuum boosting device S, and also the engine intake vacuum may be immediately supplied to the boosting device until the vacuum pressure of the vacuum chamber reaches the intake vacuum pressure of the engine, thereby the accumulation of vacuum may be made soon.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative pressure source device for a negative pressure booster used to boost a brake mask cylinder or the like in an automobile or other vehicle.・Conventionally, as a negative pressure source device for a negative pressure booster for a vehicle, a negative pressure outlet hole was provided in the suction system downstream of the throttle valve of the internal combustion engine, and the negative pressure chamber of the negative pressure booster was installed in this negative pressure outlet hole. It is known that the engine is connected via a reverse valve, and the negative pressure of the engine is stored in the chamber as the power for the booster.

By the way, depending on the type of internal combustion engine installed in the car and the type of associated equipment (for example, if the engine is a two-stroke type, if it is equipped with a multiple carburetor, or if it is equipped with an automatic transmission), the engine The negative pressure used is very low, and generally -
500'mm, II,! -30 compared to Noni, which is around 7
In some cases, only about 0-400 mall, q can be obtained. In such cases, conventionally, the pressure-receiving area of the pressure-receiving part of the booster is expanded to ensure a predetermined boost ratio. There is a problem that makes installation in an engine room or the like difficult.

The present invention was proposed in view of item 1-, and is based on an internal combustion engine 194.
By using an air ejector, even when the suction negative pressure in No. 1 is low, the high negative pressure necessary for its operation can be supplied to the negative pressure booster, and the negative pressure in the negative pressure chamber of the booster can be The simple and effective negative pressure source quickly supplies the engine's suction negative pressure to the booster C1 without relying on the air ejector until the pressure reaches the desired level, and quickly accumulates the negative pressure. The purpose of this device is to provide an air ejector whose air inlet communicates with the atmosphere, which is connected to a negative pressure outlet provided in the suction system downstream of the throttle valve of an internal combustion engine, and the air volume ( ) of the air ejector is connected to the upstream negative passage. and connect the negative pressure chamber of the negative pressure booster to the reduced pressure chamber of this air ejector via the downstream negative pressure passage, bypassing the air ejector and connecting the two downstream negative pressure passages. 21) A reverse 11 valve is installed in the bypass having a flow path resistance lower than that of the air ejector, and a second reverse valve is installed in the downstream negative pressure passage between the bypass and the negative pressure chamber. ”
1 is located where J+ is set.

Hereinafter, referring to the drawings, an embodiment of the present invention will be described. In FIG. 1, S is a known negative booster for operating a brake mask cylinder of an automobile;
A negative pressure chamber 3 is defined in the booster tank 1 by a diaphragm, (-Jboostavis) 2.E is an internal combustion engine of an automobile, and its intake system 4 includes an intake manifold 5, Part 1: The carburetor 6 has a throttle valve 7 as usual in the conventional art.The suction system 4 downstream of the throttle valve 7 has a negative pressure outlet hole 8. is provided, and this negative pressure outlet hole 8 and the negative pressure chamber 3 of the booster S
An air ejector 10 is provided in the negative pressure passage 9 connecting between the two. In the negative pressure passage 9, a portion between the negative pressure outlet hole 8 and the air ejector 10 is referred to as an upstream negative pressure passage 9a, and a portion between the air ejector 10 and the negative pressure chamber 3 is referred to as a downstream negative pressure passage 96.

As shown in FIG. 2, the main body 11 of the air ejector 100 has an air intake 12 opening at the front thereof, an air outlet 13 opening at the rear thereof, and a suction 1 opening 1 iF1 at the side thereof.
] 14, suction 014 and air volume [decompression chamber 15 and outlet 1 connected to ko 13 respectively] chamber 16, and this compartment 15.1
A diffuser 17 is provided which communicates between the air volume 1'' 13 and the downstream end of the upstream negative pressure passage 9σ, and the suction gas 14 is connected to the downstream end of the downstream negative pressure passage 9b. . The diffuser 17 has a tapered taper formed on one end surface of the decompression chamber 15, an S portion 18, a widening taper portion 19 formed on one end surface of the outlet J chamber 16, and a throat portion 20 that connects both the tapered portions 18 and 19. In the decompression chamber 15, there is a nozzle 21 connected to the air 41'J13 and with the nozzle orifice directed toward the throat 20. 1 (disposed as 1 near 1B).

Further, the main body 11 is provided with a bypass valve 22 that bypasses the diffuser 17 and has a lower flow resistance than that. . In addition, as shown in FIG. Valves 23 and 24 also supply negative pressure from the negative pressure chamber 311411.
3) The operation of this embodiment will be explained below.

Now, when the internal combustion engine E is started and negative pressure is generated in the suction system 4 downstream of the throttle valve 7, this suction negative pressure is taken out from the negative pressure outlet hole 8 and flows into the ifi path 9a. It acts on the outlet chamber 16 and the pi/% gas 22 through the. Then, the negative pressure acting on the bypass 22 opens the first reverse LF valve 23 and proceeds to the downstream negative pressure passage 9h, and then to the second check valve! 4 and reaches the negative pressure chamber 3 of the booster S, where it is stored. In this way, the negative pressure in the negative pressure chamber 3 is first rapidly increased to the level of the suction negative pressure of the engine E.

On the other hand, the negative pressure acting on the outlet chamber 16 is the diffuser 1.
With this negative IF suction force, the nozzle 21 sucks in outside air from the air inlet 1'' 12 and injects it toward the diffuser 17, creating a high-speed jet of air. Along with this, the pressure in the decompression chamber 15 is reduced, so
Suck air through the suction port 14 to further reduce the pressure in the downstream negative pressure passage 9b, that is, increase the negative pressure in the negative pressure chamber 3. And decompression chamber 1
Since the first check valve 23 is closed when the suction negative pressure of the engine E becomes higher than the suction negative pressure of the engine E, the negative pressure of the decompression chamber 15 is reliably introduced into the negative pressure chamber 3 without being short-circuited to the bypass 22. Ru. In this way, the negative pressure chamber 3 stores the total negative pressure of the suction negative pressure of the engine L' and the suction negative pressure of the air ejector 10.

If the suction negative pressure of the engine E suddenly decreases or disappears due to accelerated operation of the engine E performed by rapidly opening the throttle valve 7 or due to the operation stop of the engine E, the pressure reducing function of the air ejector 10 will decrease or stop. Since the second check valve 24 closes immediately with fl, it is impossible for 1υ-+E of the negative L chamber 3 to flow backward through the negative pressure passage 9.

As described above, according to the present invention, the air inlet [air 11 of the air ejector that communicates with the atmosphere] is injected into the negative pressure outlet provided in the intake system downstream of the throttle valve of the internal combustion engine at a rate of 1°. Since the negative pressure chamber of the negative pressure booster is connected to the reduced pressure chamber of this air ejector via the downstream negative pressure path, the air ejector is actuated by the engine's suction negative pressure, and the air ejector is The negative pressure generated in the decompression chamber of the engine is higher than the engine suction negative pressure.
Negative suction pressure can be applied to the negative end of the booster, and a desired boost ratio can be achieved without particularly expanding the pressure receiving area of the pressure receiving portion of the booster. Moreover, since there is no need to provide a special fluid pump to drive the air ejector, the configuration is simple and the negative pressure source device can be provided at low cost.
Furthermore, since there are no moving parts, there are fewer failures.

Further, since the first reverse petal is provided in the bypass which bypasses the air ejector and communicates between the second and downstream negative pressure passages and has a flow path resistance lower than that of the diffuser of the air ejector, after the engine is started, Until the negative pressure in the negative pressure chamber of the booster reaches the magnitude of the engine's intake negative pressure, the engine's intake negative pressure is quickly supplied to the negative pressure chamber of the booster mainly through the bypass, which has a small flow path resistance. , the negative pressure in the negative pressure chamber can be quickly increased, the booster can be activated quickly, and the suction negative pressure of the air ejector is higher than the engine suction negative pressure. By closing the coffin 1 check valve, Tatoshiko can prevent the suction ft pressure of the air ejector from shorting to the bypass and reliably supply this I+ to the negative pressure chamber of the booster. ．． ) OFurthermore, since a second check valve is provided in the downstream negative pressure passage between the bypass and the negative L chamber, when the engine intake negative pressure decreases or disappears, r) 11. By closing , the backflow of negative pressure from the negative pressure chamber to the negative pressure IIR circuit can be stopped, and there are effects such as being able to prevent the negative fIE of the negative pressure chamber from becoming low.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing one embodiment of the device of the present invention, 8g
Figure 2 is an enlarged longitudinal sectional side view of the main part of the air ejector. E... Internal combustion engine, S... Negative pressure booster, 3...
Negative pressure chamber, 4... Suction system, 7... Throttle valve, 8... Negative pressure outlet, 9... Negative pressure passage, 9a... Downstream negative pressure passage,
9h...Downstream negative outlet passage, 10...Air ejector, 1
2... Air inlet, 13... Air outlet, 14... Suction 1], 15... Decompression chamber, 16... ll+ I-J
Chamber, 11... Diffuser, 22... Bypass, 2
3...First check valve, 24...Second check valve row W "Applicant Nissin Kogyo Co., Ltd. Honda Motor Co., Ltd.

Claims (1)

[Claims] The air inlet 1 of the air ejector, which communicates with the atmosphere, is connected to the negative pressure outlet provided in the suction system downstream of the throttle valve of the internal combustion engine through the upstream negative pressure passage, and the A negative pressure chamber of a negative pressure booster is connected to the reduced pressure chamber via a downstream negative pressure passage, and the air ejector is connected to the negative pressure chamber of the negative pressure booster via a downstream negative pressure passage, and the air ejector is connected to the negative pressure chamber of the negative pressure booster. A negative pressure booster for a vehicle, wherein a first check valve is provided in the bypass having low road resistance, and a second check valve is provided in the downstream negative pressure passage between the bypass and the negative pressure chamber. Negative 1 ■ source device.