JPH07253071A - Fuel valve of diesel engine - Google Patents

Abstract

PURPOSE:To realize interception between a pneumatic chamber for valve opening pressure regulation and a fuel passage without increasing the weight of the movement portion of a nozzle or the like. CONSTITUTION:The fuel passage 14b of a nozzle holder 16 and the fuel passage 14a of a nozzle 12 are made to communicate with each other by putting a sleeve 15 into the head portion 13 of the nozzle 12 provided slidably in a nozzle body 11 and at the same time putting the other end of the sleeve 15 into the nozzle holder 16 slidably, and in addition a spring receiver 18 to push-press the nozzle head portion 13 is slidably provided at a pneumatic chamber 17 for valve opening pressure regulation formed between the nozzle body 11 and the nozzle holder 16 put into this body 11, and in addition seal members 20, 22 are provided face to face with the internal and external slide surfaces of the spring receiver 18, and in addition a drain hole 24 to communicate with a drain chamber 23 where the nozzle head portion 13 is interveniently placed, is provided at the nozzle body 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents leakage of air spring air from the valve opening pressure adjusting air chamber into the fuel passage and leakage of fuel oil from the fuel passage into the valve opening adjusting air chamber. The present invention relates to a fuel valve of a diesel engine that is designed to be prevented.

[0002]

2. Description of the Related Art As shown in FIG. 2, a fuel valve of a diesel engine in which an air spring is used to adjust the valve opening pressure has a valve opening adjusting air chamber 17 and a fuel passage 14 which are connected to a nozzle 12 and a nozzle holder 16. Since it is communicated through the sliding gap 30, the following problems occur. That is: a) When the pressure in the fuel passage 14 decreases after the fuel injection, not only the high pressure air in the valve-opening pressure adjusting air chamber 17 easily enters the fuel passage 14, but also the valve opening in the fuel passage 14 In a device in which fuel oil is injected by a jerk type fuel injection pump when air in the pressure adjusting air chamber 17 enters, irregularities such as variations in fuel injection amount and injection time may occur due to air mixed in the fuel oil. Cause a jet.

B) When fuel oil enters the valve-opening pressure adjusting air chamber 17 from the fuel passage 14 during the fuel injection period, it enters the air-supplying passage 25 for supplying high-pressure air to the valve-opening pressure adjusting air chamber 17. Since the fuel oil fills up and hinders the action of the air spring and causes irregular injection, a complicated discharge mechanism for discharging the fuel oil from the air supply passage 25 is required.

[0004]

SUMMARY OF THE INVENTION The present invention was devised in order to overcome the above-mentioned conventional problems, and its purpose is to open the moving part such as a nozzle without increasing the weight thereof. It is an object of the present invention to provide a fuel valve for a diesel engine that can shut off between the valve pressure adjusting air chamber and the fuel passage.

[0005]

A fuel valve for a diesel engine according to the present invention, which achieves the above object, has a sleeve fitted in a head portion of a nozzle slidably arranged in a nozzle body and at the same time, The other end is slidably fitted into the nozzle holder so that the fuel passage of the nozzle holder and the fuel passage of the nozzle communicate with each other, and further formed between the nozzle body and the nozzle holder fitted to the nozzle body. A spring receiver for pressing the head of the nozzle is slidably arranged in the valve-opening pressure adjusting air chamber, and a seal member is installed so as to face the inner and outer sliding surfaces of the spring receiver. The nozzle body is provided with a drain hole communicating with a drain chamber in which the head portion is interposed.

Here, the gap between the spring receiver slidably arranged in the valve-opening pressure adjusting air chamber and the nozzle holder is sealed by a seal ring provided in the nozzle holder, and the space between the spring receiver and the nozzle body is sealed. It is desirable to seal the gap with a seal ring provided on the spring receiver.

[0007]

When the pressure of the fuel oil in the fuel passage increases, the nozzle retracts against the air pressure in the valve-opening pressure adjusting air chamber and the spring force of the coil spring, and the nozzle hole provided at the tip of the nozzle body moves the nozzle inside the cylinder. Fuel oil is injected into. On the other hand, after fuel injection, the nozzle returns to the initial position by the air pressure in the valve-opening pressure adjusting air chamber and the spring force of the coil spring, and the nozzle tip is closed. Then, a spring receiver for pressing the head of the nozzle is slidably arranged in the valve-opening pressure adjusting air chamber formed between the nozzle body and the nozzle holder, and the inner and outer sliding surfaces of the spring receiver are exposed. Since the seal members are provided, these seal members can shut off the valve opening pressure adjusting air chamber from the nozzle holder and the fuel passage provided in the nozzle, so that the valve opening pressure adjusting air chamber enters the fuel passage. It is possible to prevent leakage of air for the air spring and leakage of fuel oil that enters the valve opening pressure adjusting air chamber from the fuel passage.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a fuel valve of a diesel engine according to the present invention. The fuel valve 10 includes a nozzle body 1
A nozzle 12 is slidably provided in the nozzle 1. A sleeve 15 is fitted in the head 13 of the nozzle 12 concentrically with the fuel passage 14 a of the nozzle 12. This sleeve 15
The other end is slidably fitted into the large-diameter portion 140 of the fuel passage 14b of the nozzle holder 16 so that the fuel passage 14a of the nozzle and the fuel passage 14b of the nozzle holder communicate with each other.

The nozzle 12 of the present invention has a head portion 1 thereof.
3 is smaller than the conventional nozzle head, and even if the sleeve 15 is attached to the nozzle head 13, the weight is the same as or lighter than the conventional nozzle. On the other hand, a spring receiver 1 for pressing the nozzle head 13 into a ring-shaped valve-opening pressure adjusting air chamber 17 formed between the nozzle body 11 and the nozzle holder 16 fitted to the nozzle body 11.
8 is slidably provided.

The gap 19 between the spring receiver 18 and the nozzle holder 16 is sealed by a seal ring 20 provided on the outer peripheral surface of the tip of the nozzle holder 16. Further, the gap 21 between the spring receiver 18 and the nozzle body 11 is sealed by a seal ring 22 provided on the outer peripheral surface of the spring receiver 18. Further, the nozzle body 11 is provided with a drain hole 24 communicating with a drain chamber 23 in the nozzle body 11 in which the head 13 of the nozzle 12 is interposed.

Further, the nozzle body 11 is provided with an air passage 25 communicating with the valve opening pressure adjusting air chamber 17, and the high pressure air supplied from the air passage 25 to the valve opening pressure adjusting air chamber 17 is provided. The valve opening pressure is adjusted by. A coil spring 26 is provided in the valve opening pressure adjusting air chamber 17. Further, a plurality of nozzle holes 28 are provided at the tip of the nozzle body 11 so as to face the combustion chamber 27.

Next, the operation of the fuel valve of the present invention having the above structure will be described. The fuel passage 14 of the fuel valve 10
When the pressure of the fuel oil in a and 14b increases, the nozzle 12 retracts against the air pressure in the valve-opening pressure adjusting air chamber 17 and the spring force of the coil spring 26, and the nozzle hole provided at the tip of the nozzle body 11 Fuel oil is injected from 28 into the combustion chamber 27.

On the other hand, after the fuel injection, the nozzle 12 is returned to the initial position by the air pressure in the valve-opening pressure adjusting air chamber 17 and the spring force of the coil spring 26 to close the nozzle tip.
The spring receiver 18 slidably provided in the valve-opening pressure adjusting air chamber 17 has a gap 19 between it and the nozzle holder 16 sealed by a seal ring 20, and at the same time, it is provided between the nozzle holder 11 and the nozzle body 11. Since the gap 21 is sealed by the seal ring 22, the seal rings 20 and 22 on both the inner and outer surfaces completely shut off between the valve opening pressure adjusting air chamber 17 and the fuel passages 14a and 14b. The air in the adjusting air chamber 17 is prevented from entering the fuel passages 14a and 14b, or the fuel oil in the fuel passages 14a and 14b is prevented from entering the valve opening pressure adjusting air chamber 17.

The air spring air and the fuel oil flowing into the drain chamber 23 in the nozzle body 11 with the nozzle head 13 interposed therebetween are discharged into the atmosphere through the drain hole 24 provided in the nozzle body 11. .

[0015]

As described above, according to the present invention, the sleeve is fitted in the head of the nozzle slidably arranged in the nozzle body, and the other end of the sleeve is slidably fitted in the nozzle holder. The fuel passage of the nozzle holder and the fuel passage of the nozzle are communicated with each other, and the valve opening pressure adjusting air chamber formed between the nozzle body and the nozzle holder fitted to the nozzle body A spring receiver that presses against the head is slidably arranged, a seal member is installed so as to face the inner and outer sliding surfaces of the spring receiver, and further, a drain communicating with a drain chamber in which the head of the nozzle is interposed. Since the hole is provided in the nozzle body, it is possible to shield the space between the valve opening pressure adjusting air chamber and the fuel passage without increasing the weight of the moving part such as the nozzle.

As a result, the air in the valve opening pressure adjusting air chamber is prevented from entering the fuel passage, or the fuel oil in the fuel passage is prevented from entering the valve opening pressure adjusting air chamber. It has become possible to eliminate irregular injection due to variations in the amount and injection time. Further, a complicated mechanism for discharging the fuel oil from the air passage is no longer necessary.

[Brief description of drawings]

FIG. 1 is a sectional view of a fuel valve of a diesel engine according to the present invention.

FIG. 2 is a sectional view of a fuel valve of a conventional diesel engine.

[Explanation of symbols]

11 Nozzle body 12 Nozzle 13 Nozzle head 14a, 14b
Fuel passage 15 Sleeve 16 Nozzle holder 17 Air chamber for adjusting valve opening pressure 18 Spring bearing 20, 22 Seal ring 23 Drain chamber 24 Drain hole

Claims (2)

[Claims] 1. A fuel passage of a nozzle holder and a nozzle, wherein a sleeve is fitted into the head of a nozzle slidably arranged in a nozzle body, and the other end of the sleeve is slidably fitted into a nozzle holder. Communication with the fuel passage of
A spring receiver for pressing the head portion of the nozzle is slidably arranged in an air chamber for adjusting the valve opening pressure formed between the nozzle body and a nozzle holder fitted to the nozzle body, and the spring is provided. A fuel valve for a diesel engine, wherein a seal member is installed so as to face inner and outer sliding surfaces of a receiver, and a drain hole communicating with a drain chamber in which the head of the nozzle is interposed is provided in the nozzle body. 2. A gap between a spring receiver and a nozzle holder slidably arranged in a valve opening pressure adjusting air chamber is sealed by a seal ring provided in the nozzle holder, and a gap between the spring receiver and the nozzle body. 2. The fuel valve for a diesel engine according to claim 1, wherein the valve is sealed by a seal ring provided on a spring receiver.