JPS6141976Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention mainly relates to improvements in a fuel pressure control valve used in a fuel injection device for an internal combustion engine.

The fuel pressure control valve functions to maintain the fuel delivered from the fuel pump at a constant pressure and return excess fuel to the tank. In other words, fuel from the tank is sent from the fuel pump to the fuel injection valve, but a fuel pressure control valve is provided at the discharge port of the pump to control the fuel pressure to the fuel injection valve and remove excess fuel. It is constantly being circulated to the tank.

Conventionally, filters for removing dust have been installed before and after the fuel pump, but these filters only remove dust that has entered the tank. Foreign matter such as dust or chips generated in the fuel pipe after the filter circulates through the pipe at least once.

Injection valves have a unique filter built into the fuel inlet to prevent serious problems if foreign matter enters the valve. However, conventionally used fuel pressure control valves do not have as many minute passages as injection valves, and therefore do not use filters. Therefore, there is a possibility that the valve may become clogged with foreign matter exceeding its passage area, and in that case, it is expected that the valve will not be able to maintain its original function.

In response to such defects, Nippondenso Public Technical Report
The fuel pressure control valve shown in No. 17-043 published on January 20, 1980 has a filter installed in the fuel inlet pipe for allowing fuel to flow into the fuel chamber.

However, when the filter is placed in such a position, it is necessary to set the fuel so that it flows smoothly through the fuel inlet pipe with the filter installed, so the filter and the filter installation base are constricted. It becomes necessary to secure a fuel flow path area by considering the flow path area, and the dimensions of the fuel flow path pipe become larger.

In addition, in terms of pressure loss due to clogging after the filter captures foreign matter, since the filter is installed in a narrow flow path called the fuel inlet pipe,
Since the filter area is small and it is difficult to set it with sufficient margin, the performance deteriorates quickly due to the pressure loss, resulting in a short product life.

In this invention, inside the fuel chamber of the fuel pressure control valve,
By incorporating a filter across the fuel chamber, it is possible to suppress the increase in size of the fuel pressure control valve, and to prevent foreign substances such as dust and chips from occurring inside the fuel pipe and the pressure control valve. In addition to maintaining the normal function of the valve, it is possible to sufficiently suppress an increase in pressure loss in the filter due to foreign matter, that is, performance deterioration due to pressure loss.

Figure 1 shows one embodiment of this committee. 1 shows the fuel pressure control valve as a whole. The fuel pressure control valve 1 has upper and lower housings 2A and 2B, and a fuel inflow pipe 5 and a fuel outflow pipe 6 are connected to the housing 2A. The flanges of the housings 2A and 2B are combined with each other while holding the periphery of the diaphragm 7. Below the diaphragm is the fuel chamber 3.
However, a pressure chamber 4 is also formed above. A fuel inflow pipe 5 and a fuel outflow pipe 6 having a flow passage cross-sectional area smaller than the flow passage cross-sectional area inside the fuel chamber 3 are opened in the fuel chamber 3, while a pressure intake pipe 41 is opened in the pressure chamber 4.
is connected to an intake manifold M downstream of a throttle valve T of an internal combustion engine E. A movable valve 8 is provided in the center of the diaphragm 7, and a valve seat 9 is provided facing the movable valve 8. The valve seat 9 is connected to the fuel outflow pipe 6 through a holding pipe 12. Further, the spring 10 urges the movable valve to seat on the valve seat 9.

According to the present invention, the filter 11 is disposed within the fuel chamber 3 so as to traverse the interior of the fuel chamber 3. The filter 11 has a hollow truncated cone shape, and the hollow part is fitted into the holding tube 12, and the outer conical part is placed on the plastic holding frame 16.
The holding frame 16 has an annular upper part 16A and an annular lower part 1.
6B, which are connected by reinforcing ribs 16C, and have a truncated conical shape as a whole. Upper 16A
is bonded to the housing 2A, and the lower portion 16B is bonded to the joint tube 12. Further, the filter 11 and the holding frame 16 are joined by welding or the like. The filter is connected to the fuel inlet pipe 5 at its tapered surface, and connected to the valve seat 9, ie, the fuel outlet pipe 6, at its upper surface. The introduced fuel passes through the filter element 11 via the passage between the ribs 16C.

Fuel sucked out from the fuel tank 101 by the fuel pump 103 passes through the filter 102 and is introduced into the control valve via the inlet conduit 5. Fuel piping 1
05 is connected to the injection valve 104. The diaphragm 7 holding the movable valve 8 is loaded by a spring 10, and this load is adjusted to a specified fuel pressure. Therefore, when the fuel pressure is higher than the set value, the valve body 8 resists the spring 10 and lifts from the valve seat 9, and fuel flows out from the gap between these 8 and 9 and returns to the fuel tank 101 through the outlet conduit 6. is,
The fuel pressure to the fuel injection valve 104 is maintained at the set value.

According to the present invention, when fuel passes through the filter 11 disposed in the fuel chamber 3 so as to cross the interior of the fuel chamber 3, foreign matter such as dust and chips generated downstream of the pump-side filter 102 is removed from the filter 11. captured by As a result, it is possible to prevent these foreign substances from getting caught between the movable valve 8 and the fixed valve 9 and the resulting deterioration of the pressure control function.

Further, in the present invention, the filter 11 is disposed in the fuel chamber 3, and this fuel chamber 3 is configured as a flow path that is sufficiently wider than the fuel inlet pipe 5, and the fuel in this fuel chamber 3 is contained in only one part of the fuel chamber 3. Since the part flows out of the fuel chamber 3 from the fuel outlet through the valve means,
By providing the filter 11, the flow of fuel within the fuel chamber 3 is not obstructed.

Furthermore, in the present invention, the area of the filter 11 can be made large and has ample area, so deterioration of performance due to pressure loss due to clogging after capturing foreign matter is suppressed, and the product life is sufficiently long. It can be done.

Furthermore, the flow rate of the fuel in the fuel inlet pipe 5;
Regarding the flow rate of fuel in the fuel chamber 3, the area of the flow path of the fuel inflow pipe 5 is much smaller than the area of the flow path of the fuel chamber 3. Therefore, if a filter is installed in the fuel inlet pipe as in the above-mentioned Nippondenso Technical Report, the force of the fuel flow acting on the filter will be greater, causing the filter to come off or break. However, if the filter 11 is provided in the fuel chamber 3 as in the present invention, the filter 1
Since the force due to the flow of fuel acting on the filter 11 is sufficiently small, the filter 11 will not come off or be damaged.

Note that the filter 11 may have any configuration and material as long as it satisfies its function. Furthermore, the passage area of the filter 11 is determined by the openings between the ribs 16C, but it goes without saying that it must be determined so as not to cause any pressure loss when the fuel passes therethrough.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line - in FIG. 1. 1...Fuel pressure control valve, 7...Diaphragm,
8...Movable valve, 9...Valve seat, 11...Filter,
16... Holding frame, 101... Fuel tank,
103...Fuel pump.

Claims (1)

[Scope of claim for utility model registration] A diaphragm that divides the inside of the housing into a fuel chamber and a pressure chamber, a fuel inlet provided in the housing on the fuel chamber side and having an opening area smaller than the cross-sectional area of the flow path in the fuel chamber, and a fuel an outlet; and valve means for controlling the flow of fuel in the fuel chamber to the fuel outlet in response to a fuel pressure determined by pressure applied from the pressure chamber to the diaphragm; A fuel pressure control valve comprising a filter disposed between an inlet and a valve means and across a fuel chamber.