JPS6016761Y2 - LPG engine fuel supply system - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a fuel supply system for an LPG engine.

Generally, a fuel supply system for an LPG engine has a vaporizer consisting of a primary chamber and a secondary chamber that are connected to each other by a communication passage, and the fuel inlet to the next chamber responds to the pressure in the next chamber. The pressurized LPG is opened and closed by a pressure-responsive type secondary valve operated by the secondary valve, and the pressurized LPG is reduced to a substantially constant pressure by the secondary valve and sent into the primary chamber.

In this case, in order to prevent freezing due to the temperature drop accompanying the evaporation of LPG, the next chamber is provided with suitable heating means.

The secondary chamber is provided with a secondary valve for opening and closing a communication path between the secondary chamber and the secondary chamber.

The secondary valve is responsive to the pressure in the secondary chamber and delivers fuel from the secondary chamber in accordance with the engine's demand while maintaining a substantially constant gaseous fuel pressure in the secondary chamber.

In this type of fuel supply system, during high-load operation with a large fuel demand, the fuel is not fully vaporized and is introduced into the primary chamber in a liquid state. , the reduction in engine fuel demand causes the secondary valve to close or close to closing.

On the other hand, a large amount of liquid fuel flows into the primary chamber due to inertia and vaporizes in the primary chamber, so that the pressure in the secondary chamber rapidly increases.

The heating means provided in the primary chamber will further promote this pressure increase.

This pressure in the primary chamber acts on the secondary valve, forcing it open and increasing the pressure in the secondary chamber.

Therefore, the amount of fuel supplied to the engine becomes excessive, and a large amount of unburned gas is released into the exhaust system.

In order to solve this problem, the fuel is preheated on the upstream side of the vaporizer and the gaseous fuel is introduced into the primary chamber, so that even when sudden deceleration occurs from high-load operation, the liquid fuel has no inertia. Although a device has been proposed (for example, see Japanese Unexamined Patent Publication No. 53-4311) that prevents the device from being introduced into the primary chamber, this device has the drawback of being complex and expensive.

The purpose of the present invention is to solve the above-mentioned problems in the fuel supply system of an LPG engine, and its structural features are: - A pressure-responsive member that responds to the pressure in the next chamber is provided to reduce the pressure in the primary chamber. Accordingly, the valve of the communication passage between the secondary chamber and the secondary chamber is biased in the closing direction.

That is, the valve that opens and closes the communication passage is supported on one end side of a valve lever that is rotatable around a support shaft, and the pressure responsive member is connected to the valve on the side opposite to the valve with respect to the support shaft via an operating rod. connected to the lever.

According to the present invention, when there is sudden deceleration from high-load operation,
Even if the liquid fuel flows into the primary chamber due to inertia and vaporizes in the primary chamber, increasing the pressure inside the coal chamber, the pressure acts on the valve lever via the pressure responsive member and causes the valve to close. The force in the valve opening direction acting on the valve through the communication path can be canceled out.

Therefore, the problem that the valve of the communication passage is pushed open due to the pressure increase in the primary chamber, increasing the pressure in the secondary chamber, and excessive fuel being supplied to the engine is prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the figure, a charcoal chamber 2 and a secondary chamber 3 are formed in a casing 1 of a vaporizer, and these chambers are connected to each other by a communication passage 4.

- A fuel population 5 is formed in the coal chamber 2, and a primary valve 6 for opening and closing this fuel population 5 is arranged within the primary chamber 2.

- The secondary valve 6 is attached to one end of the primary valve lever 8 supported by the casing 1 so as to be rotatable around the support shaft 7,
The other end of the lever 8 is attached to a diaphragm 9 arranged so that one side faces the coal chamber 2.

The chamber 10 behind the diaphragm 9 is sealed or open to the atmosphere.

A spring 11 is disposed within the chamber 10 and pushes the primary valve lever 8 in the valve opening direction via the diaphragm 9.

The pressure within the primary chamber 2 acting on the diaphragm 9 biases the valve 6 in the closing direction, so that the pressure within the primary chamber 2 can be kept approximately constant by this valve mechanism.

- A passage 12 is formed between the charcoal chamber 2 and the secondary chamber 3 for the passage of heating fluid.

A fuel outlet 13 is formed in the secondary chamber 3, and a secondary valve 14 is provided in the communication passage 4 to open and close it.

The secondary valve 14 is attached to one end of a secondary valve lever 16 that is attached to the casing 1 so as to be rotatable about a support shaft 15.

A diaphragm 17 is provided so that one side faces the secondary chamber 3, and the other end of the secondary valve lever 16 is attached to this diaphragm 17.

The chamber 18 behind the diaphragm 17 is sealed or open to the atmosphere.

A valve lever 16 is inserted into the chamber 18 via a diaphragm 17.
A spring 19 is arranged to push the valve in the valve opening direction.

A balance spring 20 acting in the valve closing direction may be provided as necessary.

Inside the primary chamber 2, there is a diaphragm 21 as a pressure responsive member.
is arranged, and one end of an operating rod 22 is connected to this diaphragm 21.

The other end of the operating rod 22 is connected to the secondary valve lever 16 on the side opposite to the secondary valve 14 with respect to the support shaft 15 .

Therefore, even if the liquid fuel flows into the primary chamber 2 due to inertia and vaporizes during a sudden deceleration from high-load operation, and the pressure inside the primary chamber 2 increases, the pressure will be reduced through the communication path 4. It acts directly on the valve 14, while acting on the diaphragm 21 to push the valve lever 16 in the valve closing direction via the actuating rod 22.

Therefore, due to the increased pressure in the primary chamber 2, the secondary valve 1
4 being pushed open is reliably prevented, and there is no fear that excess fuel will be supplied to the engine even during sudden deceleration from high-load operation.

[Brief explanation of the drawing]

The drawing is a sectional view of a vaporizer showing an embodiment of the present invention. 2...-charcoal chamber, 3...secondary chamber, 4...
...Communication path, 6...-Next valve, 9...
・Diaphragm, 14...Secondary valve, 16...
...Secondary valve lever, 17...Diaphragm,
21...Diaphragm, 22...Operating rod.

Claims (1)

[Scope of utility model registration request] a primary chamber, a secondary chamber communicating with the secondary chamber via a communication passage, a valve lever rotatably supported by a support shaft provided in the secondary chamber, and a valve lever supported on one end side of the valve lever. A fuel supply device for an LPG engine having a valve for opening and closing the communicating passage, and a heating medium passage for heating fluid in the secondary chamber, the pressure-responsive member receiving fluid pressure in the secondary chamber; an operating rod connected to the pressure responsive member, the other end of which is connected to the valve lever on the opposite side of the support shaft from the valve, and biases the valve in the closing direction by the internal pressure. L characterized by having been
PG engine fuel supply system.