JPS581647Y2 - Fuel pump pressure wave mitigation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure wave mitigation device for a fuel pump that alleviates pressure waves generated when the fuel pump of a high-speed diesel engine spills.

When a fuel pump consisting of a plunger and a barrel used in a conventional high-speed diesel engine is used, the pressure inside the plunger chamber during operation of the fuel pump is, for example, 10
There is a pressure as high as 00wC100O, and that pressure is transmitted to the fuel pipe when the fuel oil spills, causing a kind of water hammer phenomenon, which causes impact noise of all attributes to be generated in the fuel pipe, which is a problem.

In addition, if water hammer is so severe, the pressure fluctuation inside the fuel pipe is considered to be quite severe, and there is a need to be concerned about the occurrence of cavity johns similar to those inside high-pressure pipes.

Therefore, due to the fear that the inner surface of the metallic fuel pipe may be eroded by the cavity john, methods to alleviate the above-mentioned pressure waves have been considered. Although various methods have been considered, such as methods for providing such a problem, there is currently no definitive solution.

For example, in the device described in Japanese Patent Application Laid-Open No. 50-148715, when a high pressure wave propagates, the throttle plate is pressed against the main oil supply pipe side to prevent the pressure wave from propagating. A throttle hole is provided, and a portion of the pressure wave propagates toward the main oil supply pipe through the throttle hole, so it is impossible to completely prevent the pressure wave from propagating.

In addition, the one described in JP-A-52-14125 uses a check valve without a restricting hole (see Fig. 5), which can prevent the propagation of pressure waves.
Since there is no escape, there is a problem that there is no damping effect on pressure waves.

Therefore, in order to eliminate the above-mentioned conventional drawbacks, the present invention provides a pressure wave mitigation device that can prevent as much as possible the propagation of pressure waves when fuel oil spills in a fuel pump and at the same time decelerate the pressure waves as quickly as possible. It is intended to.

That is, the present invention has an umbrella-shaped lunchbox, an inner body is slidably provided in a cylindrical damping valve body, a valve seat is provided in the damping valve body with which the valve seat comes into contact, and the lunchbox is provided with an umbrella-shaped lunchbox. A fuel passage that communicates with the inside and outside of the inner body is provided on the surface of the valve part, and a small diameter fuel passage that communicates with the inside and outside of the inner body is provided in the center of the valve portion, and a fuel passage with a small diameter is provided for sealing the small diameter fuel passage. It is characterized by a sphere attached to the inner body via a spring.

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

Fig. 1 is a side sectional view showing the structure of a reflected wave attenuation valve used in an embodiment of the present invention, and Fig. 2 shows a fuel pump and main fuel pipe equipped with the reflected wave attenuation valve shown in Fig. 1. FIG. 2 is a partial cross-sectional schematic layout diagram.

1. First, to explain FIGS. 1 and 2, fuel oil sent from the main fuel pipe 2 side flows in the direction of arrow F and is sent to the fuel pump 3 via the fuel cutoff valve 4 and the reflected wave damping valve 1. The fuel is turned into high-pressure oil by the fuel pump 3, and is force-fed through the high-pressure pipe 5 to a fuel injection valve (not shown).

Therefore, the pressure waves generated when the fuel oil spills in the fuel pump 3 are transmitted in the direction of the main fuel pipe 2 as shown by the arrow P, contrary to the arrow direction F of the fuel oil.

Therefore, when the pressure wave P is transmitted to the reflected wave attenuation valve 1 shown in FIG. The umbrella-shaped valve seat part 9 contacts the valve seat 12 provided in the damping valve main body 11, and the fuel flow passages 7 provided radially in the umbrella-shaped valve seat part 9 of the inner body part 6 are all blocked. It will be done.

Further, a metal ball 10 is attached to the other end of the spring 13 fixedly installed on the opposite side of the umbrella-shaped valve portion 9 of the inner body 6, and this metal ball 10 normally obstructs the flow of fuel oil. However, when the pressure wave P is transmitted, the metal ball 10 is pushed toward the valve port 9, and the small diameter fuel flow path 8 provided at the center of the valve port 9 is also pushed out. It gets blocked.

Although the pressure wave P is transmitted in a wave form, the movement of the metal ball 10 attached to the spring and the reciprocating movement of the inner body 6 prevent the pressure wave P from being directly transmitted to the main fuel pipe 2. It acts to attenuate the pressure wave P.

As described above, in the present invention, the inner body part 6 having the umbrella-shaped valve part 9 is slidably provided in the cylindrical damping valve main body 11, and the valve part 9 is provided in the damping valve main body 11. The valve seat 12 that comes into contact with
A fuel passage 7 that communicates with the inside and outside of the inner body part 6 is provided on the circumferential surface of the valve seat part 9, and a small diameter fuel flow passage 8 that communicates with the inside and outside of the inner body part 6 is provided at the center of the valve seat part 9. and a sphere 10 for sealing the small diameter fuel flow path 8 is attached to a spring 13.
Since the inner body 6 is attached to the inner body 6 through the pressure wave, when the pressure wave propagates, the inner body 6 moves in the direction of the arrow P and blocks the valve seat 12, and the sphere 10 blocks the small diameter fuel flow path 8. On the other hand, when the pressure waves hit the inner body 6 and the sphere 10 and are reflected, the spring 13 separates the sphere 10 from the fuel flow path 8 and communicates between the inside and outside of the inner body 6, and the sphere 10 repeatedly opens and closes the fuel flow path 8, thereby preventing the pressure waves from propagating and simultaneously attenuating the pressure waves.

Note that the present invention is particularly effective for diesel engines that perform high-pressure fuel injection.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the structure of a reflected wave attenuation valve used in an embodiment of the present invention, and Fig. 2 shows a fuel pump and main fuel pipe equipped with the reflected wave attenuation valve shown in Fig. 1. FIG. 2 is a partial cross-sectional schematic layout diagram. 1... Reflected wave attenuation valve, 2... Main fuel pipe, 3...
Fuel pump, 6...inner body, 7, 8... fuel flow path,
9... Valve portion, 10... Metal ball, 11... Damping body main body, 12... Valve seat, 13... Spring.

Claims (1)

[Scope of utility model registration request] An inner body 6 having an umbrella-shaped valve portion 9 is connected to a cylindrical damping valve body 1.
1, a valve seat 12 is provided in the damping valve main body 11 and the valve seat 12 contacts the valve seat 9, and a fuel passage communicates with the inside and outside of the inner body 6 on the circumferential surface of the valve seat 9. 7, a small-diameter fuel passage 8 communicating with the inside and outside of the inner body part 6 is provided at the center of the valve stop part 9, and a sphere 10 for sealing the small-diameter fuel passage 8 is connected to the inner body via a spring 13. Pressure wave mitigation device for the fuel pump attached to section 6.