JP2511652Y2 - Air bleeder for engine with fuel cutoff valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is to connect a feed pump, a fuel cutoff valve, and an air vent plug to a fuel supply path in order from the fuel tank side, and connect the air vent plug from the fuel tank. Also, the present invention relates to an air bleeder for an engine with a fuel cutoff valve that includes a valve body that is located at a low position and that is opened in the fuel cutoff valve against a valve spring by a feed pressure.

(Prior Art) Generally, an emergency engine needs to be started immediately in the event of a power outage of commercial power, etc., but is usually left in an engine stopped state for a long time. During this time, air may enter the supply path from the seal of the fuel feed pump or the plunger gap of the fuel injection pump.Therefore, by installing the fuel tank high and applying the head pressure, the fuel leak may occur. Even if there is, I try not to let air in.

However, the fuel injection pump 2 having the structure in which the plunger 42 and the drive tappet 43 are integrally incorporated as shown in FIG.
Since the lower part of the plunger 42 faces the inside of the engine, if the head pressure is always applied when the engine is stopped as described above, fuel oil will enter the engine from the gap between the plunger 42 and the valve body 41. Leak. Especially in the case of fuel oil having a low viscosity such as kerosene, the amount of oil leakage increases. The leaked oil mixes with the lubricating oil inside the engine and causes deterioration of the lubricating oil performance.

Therefore, when the fuel injection pump 2 as shown in FIG. 5 is used, it is necessary to provide a shutoff valve for shutting off the fuel during engine stop in order to prevent fuel oil from mixing into the engine during engine stop. As a result, an air bleeding device for air bleeding work is required.

As a conventional air bleeder for an engine with a fuel cutoff valve, for example, there are a hand pump type as shown in FIG. 6 and a bypass valve type as shown in FIG.

In the air bleeding device of FIG. 6, a hand pump 53 is connected in parallel to a check valve 51 upstream of the feed pump 5 (fuel tank 1 side), and a downstream side of the fuel cutoff valve 50 (fuel injection pump 2
An air bleeding plug 7 is arranged on the side) and a bypass circuit 10 having a check valve 8 is connected in parallel to the feed pump 5. When bleeding air, open the air bleeding plug 7 and pass the check valve 8 through the hand pump 53 to the fuel cutoff valve.
Fuel oil is pressure-fed to 50, thereby pushing open the fuel cutoff valve 50, and bleeding air from the air bleeding plug 7.

However, this device is costly because the hand pump 53 is necessary, and the pump operation must be continued manually during the air bleeding, which requires a lot of work.

In the air bleeding device of FIG. 7, a bypass circuit 57 is provided in parallel with the fuel cutoff valve 50, an opening / closing valve 56 is provided in the bypass circuit 57, and air is bleeding downstream of the fuel cutoff valve 50 (fuel injection pump 2 side). The plug 7 is arranged. When bleeding air, open the on-off valve 56 of the bypass circuit 57 of the fuel cutoff valve 50,
Air is evacuated from the air bleeding plug 7 by the head pressure of the fuel oil. After the work is completed, the open / close valve 56 is closed.

However, providing the bypass circuit 57 in the shutoff valve 50 is costly, and there is a possibility that the fuel shutoff function of the shutoff valve 50 may be stopped due to forgetting to close the open / close valve 56 after the air bleeding operation.

(Purpose of the Invention) The purpose of the present invention is to eliminate the trouble of manual priming operation using a hand pump, to easily perform air bleeding work, and to be small in size, low in cost, and capable of automatically preventing the shutdown of the shutoff valve. An air bleeder for an engine with a shutoff valve.

(Technical Means for Achieving the Purpose) In order to achieve the above-mentioned object, according to the present invention, a feed pump, a fuel cutoff valve, and an air vent plug are sequentially connected from the fuel tank side, and the air vent plug is connected to the fuel tank. In an engine with a fuel cutoff valve that is located at a low position and has a valve body that opens in the fuel cutoff valve against a valve spring due to a feed pressure, a valve that can be pressed into contact with the end face of the valve body on the fuel inlet side. A push rod is provided on the fuel cutoff valve so that it can be pushed in from the outside, and the valve push rod is biased to a standby position apart from the valve body by a return spring. It is configured to open.

(Function) When bleeding air, open the air bleeding plug and push the valve push rod to the push-in position to open the valve body a little and the head pressure of the fuel tank is applied to the downstream side of the fuel cutoff valve.
Due to the head pressure, the air in the fuel supply system is naturally discharged from the air vent plug.

After releasing the air, when you release your hand from the valve push rod, the valve push rod automatically returns to the standby position by the return spring.

(Embodiment) FIG. 4 is a piping diagram of a fuel supply system of an engine with a shutoff valve equipped with an air bleeding device according to the present invention.
Is arranged at a position higher than the engine for ensuring head pressure and the air vent plug 7, and the fuel supply pipes 12 and 13 between the fuel tank 1 and each fuel injection pump 2 are connected to the fuel tank 1 side from the fuel tank 1 side. A feed pump 5, a fuel cutoff valve 6 and the air vent plug 7 are provided in this order. A fuel injection valve 3 is connected to each fuel injection pump 2.
The feed pump 5 is provided with a bypass circuit 9 in parallel therewith, and the bypass circuit 9 is provided with a check valve 8 for passing the fuel oil only from the fuel tank 1 side to the fuel cutoff valve 6 side.

The fuel injection pump 2 has a pump body 41 as shown in FIG.
The plunger 42 and the drive tappet 43 are integrally formed, and the lower half of the plunger 42 is located inside the engine. 45 is an oil leak passage. The oil leak is discharged to the oil sump outside the engine by a pipe connected to the passage 45.

FIG. 1 shows an enlarged vertical sectional view of the fuel cutoff valve 6,
A valve body 17 is fitted on the inner peripheral surface of the valve body 15 so as to be movable in the valve axial direction. The valve body 17 has a fuel oil inlet side end surface 17a formed in a tapered shape (a gentle conical shape). And the taper end surface
An O-ring 28 is fitted around 17a. A plurality of oil passage holes 23 are formed at positions corresponding to the inner peripheral annular groove 21 of the valve body 15 in the axial direction of the valve body 17.

A spring retainer 27 is screwed to the fuel oil outlet side portion of the valve body 15, and a valve spring 26 is contracted between the spring retainer 27 and the valve body 17, and the valve spring 26 is used to fuel the valve body 17. By energizing the oil inlet side (valve closing side), the valve element 17 is seated on the valve seat 18 to shut off the fuel.

The set load of the valve spring 26 is smaller than the feed pressure of the feed pump 5 (Fig. 4), and the valve body 17 is compressed by the feed pressure to open the valve body 17, and the fuel tank 1
It is set to a strength that is larger than the head pressure of the fuel oil shown in FIG. 4 and does not open depending on the head pressure.

The valve pushing device 11 having the valve pushing rod 32 is arranged on the fuel oil inlet side of the shutoff valve 6, and in addition to the valve pushing rod 32, a nipple type valve pushing rod guide having screws 38 and 39 at both ends. 30
And a cap nut 31 and the like. A female screw hole 14 orthogonal to the valve shaft O is formed in the peripheral wall of the fuel oil inlet side passage 25 of the valve body 15, and one screw portion 39 of the valve push rod guide 30 is screwed into the female screw hole 14. A packing 33 is sandwiched between the flange portion 37 of the valve push rod guide 30 and the outer periphery of the valve body 15.

The valve push rod 32 has a valve shaft center O
An O-ring 29 is arranged between the valve push rod 32 and the inner peripheral surface of the tip end portion of the valve push rod guide 30 so as to be slidable in a direction perpendicular to the valve push rod 32.

The cap nut 31 is screwed to the other external thread portion 38 of the valve push rod guide 30 to pressurize the O-ring 29.

A handle 34 is fixed to the end of the valve push rod 32 on the outer side of the valve body, and a return spring 35 is contracted between the handle 34 and the cap nut 31, and the return spring 35 causes the valve push rod 32 to move as shown in FIG. As described above, it is urged to the standby position which has retreated from the entrance passage 25.

An enlarged collar-shaped valve pushing portion 32a is formed at an end portion of the valve pushing rod 32 on the inner side of the valve body, and the valve pushing portion 32a is formed with a tapered surface. In the standby position shown in FIG. 1, the valve pushing portion 32a is separated from the taper end surface 17a of the valve body 17 in the closed state, and by pushing the valve pushing rod 32, the taper of the valve body 17 is tapered as shown in FIG. The valve body 17 is slightly opened by a cam action by being pressed against the end surface 17a.

The operation will be described. When the engine is operating, the valve spring 26 is compressed by the feed pressure of the feed pump 5 as shown in FIG.
17 is opened, and the fuel oil is supplied to the fuel injection pump 2 shown in FIG. Since the internal pressure of the engine or the atmospheric pressure is higher than the atmospheric pressure during the operation of the engine, the oil leakage from the outer circumferential gap of the plunger 42 in FIG. 5 is released from the oil leakage passage 45 to the oil leakage reservoir outside the engine. No fuel oil leaks inside the engine.

When the engine is stopped, the valve body 17 is not opened by the head pressure as shown in FIG. 1, so the fuel cutoff valve 6 is closed, the head pressure is not applied to the fuel injection pump 2 in FIG. 4, and fuel leakage is prevented. To be done.

When bleeding air, first open the air bleeding plug 7 shown in FIG. 4, and then push the valve push rod 32 to the push-in position as shown in FIG. As a result, the valve body 17 has its tapered end surface 17
It is opened a little by the cam action between a and the valve pushing part 32a.

In this state, the head pressure of the fuel oil in the fuel tank 1 is the same as the fuel pipe 12 and the bypass circuit 9 of the feed pump 5.
Through the fuel cutoff valve 6, the fuel pipe 13 and the air vent plug 7, and the air in the fuel supply system is naturally discharged from the air vent plug 7 by the head pressure.

After releasing the air, release the handle 34 and
Is automatically returned to the standby position by the return spring 35.

(Effect of the Invention) As described above, according to the present invention, the air vent plug 7 is positioned lower than the fuel tank 1, and the valve body is opened in the fuel cutoff valve 6 against the valve spring 26 by the feed pressure. In an engine with a fuel cutoff valve equipped with 17, a valve push rod 32 that can be pressed into contact with the end face of the valve body 17 of the fuel cutoff valve 6 is provided so that it can be pushed in.
Since the valve body 17 is biased to the standby position away from and the valve body 17 is pushed open by an appropriate amount when pushed to the pushing position, there are the following advantages.

(1) By simply pressing the valve push rod 32, the shutoff valve 6 can be opened, and air can be automatically bleeded by the head pressure. Therefore, unlike the conventional hand pump type, the manual priming operation does not require time and labor. Air bleeding work becomes easy.

(2) Since the hand pump is not required and the shutoff valve 6 does not need to have the bypass circuit 57 as shown in FIG. 7, downsizing and cost reduction can be achieved.

(3) After the air bleeding is completed, if the handle 34 of the valve push rod 32 is released, the return spring 35 automatically returns the valve push rod 32 to the standby position. Therefore, as shown in FIG.
It is possible to prevent the shutoff valve from stopping due to forgetting to close the on-off valve 57.

[Brief description of drawings]

1 to 3 show a fuel cutoff valve equipped with an air bleeding device according to the present invention. FIG. 1 shows a state when the engine is stopped, FIG. 2 shows a state when the air is bleeding, and FIG. 3 shows a state when the engine is in operation. FIG. 4 is an enlarged vertical cross-sectional view, FIG. 4 is a piping view of a fuel supply system of an engine equipped with an air bleeding device according to the present invention, FIG. 5 is a vertical cross-sectional partial view of a fuel injection pump, and FIGS. It is a fuel supply system piping diagram of the engine provided with the conventional air venting device.
1 ... Fuel tank, 5 ... Feed pump, 6 ... Fuel shutoff valve, 7 ... Air bleed plug, 17 ... Valve body, 26 ... Valve spring, 32 ... Valve push rod, 32a ... Valve push Part, 35 ... Return spring

Claims (1)

(57) [Scope of utility model registration request] 1. A feed pump, a fuel cutoff valve and an air vent plug are sequentially connected from the fuel tank side, the air vent plug is positioned lower than the fuel tank, and a valve spring is provided in the fuel shutoff valve by a feed pressure. In an engine with a fuel cutoff valve having a valve body that opens against a valve, a valve push rod that can be pressed into contact with the end surface of the valve body on the fuel inlet side is provided in the fuel cutoff valve so as to be pushed in from the outside. The push rod is urged to a standby position away from the valve body by a return spring, and when the push rod is pushed to the pushing position, the push rod is configured to push open an appropriate amount. Air bleeding device.