JP3206361B2 - Fuel supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for supplying fuel to a fuel injection valve, and more particularly to a technique for absorbing fluctuations in fuel pressure in a delivery pipe during fuel injection.

[0002]

2. Description of the Related Art In an electronically controlled fuel injection engine of an automobile or the like, fuel supplied from a fuel pump via a feed pipe is injected into a surge chamber or an intake pipe from a fuel injection valve driven and controlled by an ECU. In the fuel pump, the discharge pressure is set so as to obtain a predetermined injection pressure,
The discharge amount is also set so that sufficient fuel supply can be performed at the time of full-open running. Therefore, when supplying fuel to the fuel injection valve, the fuel pressure is adjusted to a predetermined value by using a fuel pressure regulator, and excess fuel is returned to the fuel tank. The fuel pressure regulator has a diaphragm, a spring, a valve, and the like housed in a metal body. In multipoint injection, the fuel pressure regulator is arranged at the end of a delivery pipe to which a fuel injection valve is attached, and the excess fuel after pressure adjustment is removed. The structure is such that the fuel is returned to the fuel tank via the return pipe.

In such a conventional fuel supply apparatus, a feed pipe and a return pipe must be provided between a fuel tank and a fuel injection valve in an engine room, and thus cost and assembly man-hours are increased. There were drawbacks. Further, the fuel returned from the return pipe to the fuel tank is heated by the hot air in the engine room and the like, and the fuel evaporative gas (hereinafter simply referred to as "evaporated gas") in the fuel tank during traffic congestion or the like where the amount of recirculation increases. There was also a problem of increasing the amount of generation. Since the evaporative gas in the fuel tank is mainly composed of HC harmful to the human body, the evaporative gas is adsorbed by the canister of the evaporative gas emission suppression device, introduced into the intake pipe as a purge gas, and burned together with fresh air. However, when the generated amount of the evaporative gas is too large, there occur problems such as an overflow due to insufficient adsorption capacity of the canister and an inability to accurately control the air-fuel ratio due to an excessively rich purge gas.

Therefore, Japanese Patent Application Laid-Open No. Hei 5-321784 proposes a returnless type fuel supply device in which a fuel pressure regulator is installed near a fuel tank or the like. In this type of fuel supply system, a return pipe is not installed in the engine room, so that high-temperature fuel does not flow back to the fuel tank, reducing the amount of evaporative gas generated and reducing the number of parts and assembly steps. I do.

[0005]

However, the accuracy of the fuel injection amount control, which is necessary for the air-fuel ratio control, also deteriorates in the above-described returnless fuel supply device due to the fluctuation of the fuel pressure in the delivery pipe. There was a problem. That is, the ECU
Controls the fuel injection amount by the opening time of the fuel injection valve, but the fuel pressure in the delivery pipe fluctuates (decreases) at the moment when fuel is injected from the fuel injection valve, and the fuel injection per unit opening time The amount is not constant. In the conventional device, the fuel pressure regulator provided near the delivery pipe absorbs the fuel pressure fluctuation, but the fuel pressure regulator installed near the fuel tank or the like cannot absorb the fuel pressure fluctuation. Therefore, depending on the arrangement of the fuel injection valves on the delivery pipe and the order of fuel injection, the amount of fuel injection from each fuel injection valve differs even during the same valve opening time, causing fluctuations in engine rotation and an increase in harmful exhaust gas components. Was a factor that occurred. Therefore, an attempt was made to provide a fuel pressure fluctuation absorbing device in the vicinity of the delivery pipe to absorb the fuel pressure fluctuation, but using a diaphragm, a spring, or the like would increase the manufacturing cost, and the advantage of making the fuel supply device a returnless type. There was a problem of halving.

The present invention has been made in view of the above circumstances, and has a relatively simple and inexpensive structure, and is capable of effectively absorbing fuel pressure fluctuations during fuel injection over a long period of time. It is intended to provide a supply device.

[0007]

Therefore, according to the present invention, there is provided a fuel tank for storing fuel, a fuel pump for pressurizing and supplying fuel in the fuel tank, and a fuel pump for supplying fuel from the fuel pump. Pressure adjusting means for adjusting the pressure to a predetermined pressure, and to supply the combustion chamber of each cylinder of the multi-cylinder internal combustion engine,
A plurality of fuel injection valves for injecting fuel, a delivery pipe for distributing fuel to these fuel injection valves, a feed pipe for supplying fuel from the fuel pressure adjusting means to the delivery pipe, and a delivery pipe for And a fuel pressure fluctuation absorbing means for absorbing a fuel pressure fluctuation generated in the delivery pipe when the fuel injection valve injects the fuel by an expansion effect of the pressurized gas, wherein the fuel pressure fluctuation absorbing means comprises the delivery pipe. The present invention proposes a fuel supply device having a film body made of an elastic material for partitioning a gas chamber into a fuel chamber and a damper chamber, and a pressurized gas and a viscous fluid sealed in the damper chamber.

According to a second aspect of the present invention, there is provided a fuel supply apparatus in which the fuel pressure fluctuation absorbing means includes a hollow body made of an elastic material, and a pressurized gas and a viscous fluid sealed in the hollow body. .

According to a preferred aspect of the present invention, in the fuel supply device of the first aspect, the damper chamber is preferably formed in a casing fixed to the delivery pipe. At this time, it is preferable that the casing is disposed above the delivery pipe.

Further, in the fuel supply device according to claim 2,
Preferably, the hollow body is housed in a casing fixed to the delivery pipe. Further, in the fuel supply device according to claim 1 or 2, it is preferable that the elastic material is synthetic rubber. Further, in the fuel supply device according to claim 1 or 2, it is preferable that the viscous fluid is silicone oil.

According to claim 3 of the present invention, claim 1 or claim 2
Or 2) a fuel supply device in which the fuel pressure adjusting means is provided near the fuel tank or in the fuel tank.

[0012]

In the fuel supply device according to the first aspect, when fuel is injected from the fuel injection valve and the fuel pressure in the delivery pipe is reduced, the pressurized gas in the damper chamber constituting the fuel pressure fluctuation absorbing means expands, and the reduced fuel pressure is obtained. Is returned to a predetermined value. At this time, since the surface of the membrane is covered with the viscous fluid, the pores of the membrane are blocked by the viscous fluid, and the pressurized gas does not leak to the fuel chamber side.

In the fuel supply device according to the second aspect, when the pressurized gas expands due to a decrease in the fuel pressure, the volume of the hollow body increases and the fuel pressure increases. At this time, the inner surface of the hollow body is covered with the viscous fluid. As a result, the pores of the hollow body are closed by the viscous fluid, and the pressurized gas does not leak to the fuel side. Claim 1
In a preferred embodiment of the fuel supply device, for example,
A damper chamber is formed in the casing in advance by enclosing the viscous fluid and attaching the membrane, and then the casing is assembled to the delivery pipe.

In this case, in a more preferred embodiment, a layer of viscous fluid is interposed between the pressurized gas and the membrane due to a difference in specific gravity, so that the pressurized gas is less likely to leak to the fuel chamber side. In a preferred aspect of the fuel supply device of the second aspect, the hollow body does not move in the delivery pipe, and the fuel passage to the fuel injection valve is not blocked by the hollow body. In another preferred embodiment of the fuel supply device according to the first or second aspect, when the pressurized gas expands or contracts when the fuel pressure fluctuates, the membrane or the hollow body elastically deforms in a stable state for a long period of time.

In a further preferred aspect of the fuel supply device according to the first or second aspect, even when the temperature of the fuel rises or when the fuel is used for a long period of time, the deterioration of the viscous fluid and the chemical reaction with the membrane are prevented. No reaction occurs. In the fuel supply device according to the third aspect, since the adjustment of the fuel pressure is performed in the vicinity of or inside the fuel tank, there is no return of excess fuel from the delivery pipe to the fuel tank.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel supply device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a layout diagram of a front engine passenger car employing the present invention. As shown in this figure, the fuel tank 1 is arranged at the rear part of the vehicle body 2, and refueling is performed via a refueling pipe 3 formed integrally. The fuel tank 1 has a built-in fuel pump 4, which pressurizes the fuel and feeds the fuel to a fuel pressure regulator 5 disposed immediately before the fuel tank 1. The fuel pressure regulator 5 is a known one in which a diaphragm, a spring, a valve body and the like are housed in a metal body, and regulates fuel to a predetermined set pressure. The fuel pressure regulator 5 is connected to a feed pipe 7 for supplying fuel after pressure regulation to an engine room 6 formed in a front part of the vehicle body 2 and a return pipe 8 for returning surplus fuel to the fuel tank 1. I have. on the other hand,
In the engine room 6, an in-line four-cylinder gasoline engine (hereinafter simply referred to as engine) 9 is mounted horizontally. The intake manifolds 10 of the engine 9 are provided with fuel injection valves 11 for the number of cylinders, and fuel from the feed pipe 7 is distributed to the fuel injection valves 11 by the delivery pipe 12.

FIG. 2 shows a first embodiment of the present invention in a longitudinal section. The delivery pipe 12 is a hollow metal pipe, and four fuel injection valves 11 are attached to the lower part thereof, and the feed pipe 7 is connected to the right end. In the case of the present embodiment, the fuel pressure fluctuation absorbing means is protruded above the delivery pipe 12 and has the following configuration. That is, as shown in FIG. 3 (enlarged view of part III in FIG. 2),
At the center of the delivery pipe 12, a seat 13 and a communication hole 14 are provided.
And a casing 16 is bolted to the seating surface 13 via a gasket 15. The casing 16 is a hollow casting, and the hollow portion 17 communicates with the delivery pipe 12 through the communication hole 14. A diaphragm (membrane) 18 made of a fluorine-based synthetic rubber is disposed below the casing 16. The internal space of the casing 16 and the delivery pipe 12 is partitioned by a diaphragm 18 into a fuel chamber 19 and a damper chamber 20. Further, a high-viscosity silicone oil (viscous fluid) 21 and pressurized nitrogen are provided on the damper chamber 20 side. Gas 22 is enclosed. In the figure, reference numeral 23 denotes a locking ring for fixing the diaphragm 18 to the casing 16.

In the first embodiment, when the driver operates the ignition key to start the engine 9, the fuel pump 4
After the fuel in the fuel tank 1 is pressurized by the fuel pressure regulator 5, the fuel is supplied to the delivery pipe 12 through the feed pipe 7. When fuel is sequentially injected from each fuel injection valve 11 driven by an ECU (not shown), the fuel pressure in the delivery pipe 12 intermittently decreases. However, in the apparatus according to the present embodiment, when fuel is injected from a certain fuel injection valve 11 and the fuel pressure is reduced, the nitrogen gas 22 in the damper chamber 20 expands at that moment, and the diaphragm 18 is pushed down to the fuel chamber 19 side. Can be As a result, the fuel pressure in the delivery pipe 12 increases, and returns to the set pressure when the next fuel injection from another fuel injection valve 11 is performed. Accordingly, fuel is injected from each fuel injection valve 11 in an amount corresponding to the valve opening time,
This eliminates problems such as fluctuations in engine rotation and an increase in harmful exhaust gas components, which are problems in conventional devices.

Although it is inevitable that fine pores are present in the synthetic rubber diaphragm 18, when the high viscosity silicone oil 21 is in contact with the surface, these pores are blocked by the silicone oil 21. It is. Therefore,
The nitrogen gas 22 is prevented from leaking from the damper chamber 20 to the fuel chamber 19 side, the pressure of the nitrogen gas 22 does not drop, and the expected fuel pressure fluctuation absorbing performance is permanently maintained.

FIG. 4 shows a second embodiment of the present invention in a vertical cross section. In this embodiment, the fuel pressure fluctuation absorbing means is protruded from the end of the delivery pipe 12 and has the following configuration. That is, the delivery pipe 12
Is open at the end and has an internal thread 25
Are formed. The casing 16 has an external thread 26 formed on an outer peripheral surface of an end portion thereof, and is connected to the delivery pipe 12 by being screwed. In the figure, 15
Is a gasket. Also in this embodiment, the casing 1
Reference numeral 6 denotes a hollow casting, and a hollow portion 17 thereof communicates with the inside of the delivery pipe 12. At the open end of the casing 16, a diaphragm 18 is disposed, and a locking ring 23 is provided.
It is fixed by. The internal space of the casing 16 and the delivery pipe 12 is partitioned by the diaphragm 18 into a fuel chamber 19 and a damper chamber 20, and a high-viscosity silicone oil 21 and a pressurized nitrogen gas 22 are further provided on the damper chamber 20 side. It is enclosed.

The operation of the device of the second embodiment is the same as that of the first embodiment, and the decrease in fuel pressure due to fuel injection is absorbed by the expansion of the nitrogen gas 22. However, in the case of the present embodiment, it is possible to relatively easily provide the fuel pressure fluctuation absorbing means even for the existing delivery pipe 12 by processing the female screw 25 or the like. Also, the shape of the casing 16 is relatively simple, and sometimes the bolt is not tightened, so that the manufacturing cost and the number of assembly steps are smaller than those of the apparatus of the first embodiment. Since the silicone oil 21 forms a thin film on the surface of the diaphragm 18, even if the silicone oil 21 is biased toward the end of the casing 16 due to the inclination of the delivery pipe 12, the pores of the diaphragm 18 are blocked and nitrogen Leakage of the gas 22 is prevented.

FIG. 5 shows a third embodiment of the present invention in a longitudinal sectional view. In the present embodiment, similarly to the first embodiment, the fuel pressure fluctuation absorbing means is provided protruding above the delivery pipe 12 and has the following configuration. That is, a seating surface 13 and a communication hole 14 are formed in a central portion of the delivery pipe 12, and a gasket 15 is formed on the seating surface 13.
, The casing 16 is bolted. The casing 16 is a hollow casting, and the hollow portion 17 communicates with the delivery pipe 12 through the communication hole 14.
At a lower portion of the casing 16, a retaining plate 31 having a large number of communication holes 30 is provided, and is fixed by a locking ring 23. A hollow ball (hollow body) 32 made of a fluorine-based synthetic rubber is disposed inside the casing 16, and is held by a retaining plate 31 so as not to fall into the delivery pipe 12. In the ball 32, a high-viscosity silicone oil 21
And pressurized nitrogen gas 22 are injected, and an injection hole (not shown) is closed by welding or the like.

In the third embodiment, when the fuel pressure is reduced by the fuel injection, the nitrogen gas 22 inside expands, the outer diameter of the ball 32 increases, and the fuel in the casing 16 flows from the communicating hole 30 of the retaining plate 31. It flows into the delivery pipe 12. As a result, the fuel pressure fluctuation in the delivery pipe 12 is absorbed, and the fuel injection valves 11
After that, the amount of fuel proportional to the valve opening time is injected. In this embodiment, as in the second embodiment, the silicone oil 21 forms a thin film on the inner surface of the ball 32, so that the pores of the ball 32 are closed and the nitrogen gas 22 is prevented from leaking. .

With the above, the description of the concrete embodiment is finished.
Embodiments of the present invention are not limited to this embodiment. For example, in each of the above-described embodiments, the casing is attached to the delivery pipe to constitute the fuel pressure fluctuation absorbing means. For example, a diaphragm is directly assembled in the delivery pipe, or the ball is held by the delivery pipe itself. The casing may be eliminated by a method or the like. Further, a synthetic rubber or the like other than fluorine may be used as a material of the diaphragm or the ball, and a fluid or a pressurized gas other than silicone oil or nitrogen gas may be used. In addition, the specific configuration of the device can be appropriately changed without departing from the gist of the present invention.

[0025]

According to the fuel supply device of the first aspect of the present invention, a fuel tank for storing fuel, a fuel pump for pressurizing and supplying fuel in the fuel tank, and a fuel pump from the fuel pump are provided. Fuel pressure adjusting means for adjusting pressure to a predetermined pressure, a plurality of fuel injection valves for injecting fuel to supply the combustion chambers of each cylinder of the multi-cylinder internal combustion engine, and a delivery pipe for distributing fuel to these fuel injection valves. A feed pipe provided for supplying fuel from the fuel pressure adjusting means to the delivery pipe, and a fuel pressure fluctuation which is attached to the delivery pipe and occurs in the delivery pipe when the fuel injection valve injects fuel. A fuel pressure fluctuation absorbing means for absorbing the pressure by the expansion action of the pressurized gas, wherein the fuel pressure fluctuation absorbing means comprises a film body made of an elastic material which partitions the delivery pipe into a fuel chamber and a damper chamber; Since the so pressurized gas sealed in the damper chamber and has a viscous fluid, the fuel from the fuel injection valve is injected fuel pressure in the delivery pipe is decreased,
The compressed gas in the damper chamber, which constitutes the fuel pressure fluctuation absorbing means, expands and returns the reduced fuel pressure to a predetermined value to prevent engine rotation fluctuation and increase in harmful exhaust gas components due to deterioration of fuel injection amount control accuracy. but is the, this time, by the surface of the film structure is covered with the viscous fluid, the pores of the membrane body is closed by a viscous flow <br/> body, the fuel pressure due to leakage into the fuel chamber side of the pressurized gas The fluctuation absorption performance is unlikely to be reduced.

[0026]

According to the fuel supply device of the second aspect,
The fuel pressure fluctuation absorbing means, a hollow body made of an elastic material,
Since the hollow body is filled with the pressurized gas and the viscous fluid, the inner surface of the hollow body is covered with the viscous fluid, so that the pores of the hollow body are closed by the viscous fluid,
The fuel pressure fluctuation absorption performance does not deteriorate due to the leakage of the pressurized gas to the fuel chamber side.

In a preferred embodiment of the fuel supply device according to the present invention, the damper chamber is formed in a casing fixed to the delivery pipe.
Thereby, the assemblability can be improved by assembling the casing in which the damper chamber is formed in advance to the delivery pipe. In this case, as a further preferred embodiment, the casing is preferably disposed above the delivery pipe, whereby a layer of a viscous fluid is formed between the pressurized gas and the membrane due to a difference in specific gravity. As a result, the fuel pressure fluctuation absorbing performance due to the leakage of the pressurized gas to the fuel chamber side is more unlikely to occur.

[0029] In a preferable embodiment of the fuel supply apparatus according to claim 2, wherein the hollow body is to be housed in a casing that is fixed to the delivery pipe is good, thereby, the hollow body is in the delivery pipe Does not block the fuel passage to the fuel injection valve. In another preferred embodiment of the fuel supply device according to claim 1 or 2 , the elastic material is preferably made of synthetic rubber, whereby the membrane or the hollow body is elastically deformed in a stable state for a long time, Fuel pressure fluctuation absorption performance is ensured.

In a further preferred aspect of the fuel supply device according to the first or second aspect, the viscous fluid is preferably silicone oil, so that the temperature of the fuel rises or the fuel is used for a long time. In such a case, the deterioration of the viscous fluid and the chemical reaction with the film body do not occur, and the fuel pressure fluctuation absorbing performance is secured. According to the fuel supply device of the third aspect, in the fuel supply device of the first or second aspect, the fuel pressure adjusting means is provided near the fuel tank or in the fuel tank. The generation of evaporative gas in the fuel tank due to the reflux is suppressed, and a return pipe or the like is not required, so that the number of parts and the number of assembly steps are reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a fuel supply device according to the present invention.

FIG. 2 is a longitudinal sectional view of a delivery pipe provided with fuel pressure fluctuation absorbing means of the first embodiment.

FIG. 3 is an enlarged view of a part III in FIG. 2;

FIG. 4 is an enlarged longitudinal sectional view of a main part showing a fuel pressure fluctuation absorbing unit of a second embodiment.

FIG. 5 is an enlarged vertical sectional view of a main part showing a fuel pressure fluctuation absorbing unit of a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Body 4 Fuel pump 5 Fuel pressure regulator 7 Feed pipe 9 Engine 11 Fuel injection valve 12 Delivery pipe 16 Casing 18 Diaphragm 19 Fuel chamber 20 Damper chamber 21 Silicone oil 22 Nitrogen gas 31 Retaining plate 32 Ball

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-72795 (JP, A) JP-A-8-4615 (JP, A) JP-A-61-59094 (JP, A) 20620 (JP, U) Fully open sho 56-111269 (JP, U) Fully open sho 60-110676 (JP, U) Fully open sho 57-100693 (JP, U) Fully open sho 63-126601 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) F02M 55/02 F02M 55/02 310 F02M 55/02 350 F02M 55/04 F02M 37/00 F16L 55/04

Claims (3)

(57) [Claims] 1. A fuel tank for storing fuel, a fuel pump for pressurizing and sending fuel in the fuel tank, fuel pressure adjusting means for adjusting fuel from the fuel pump to a predetermined pressure, and a multi-cylinder. A plurality of fuel injection valves for injecting fuel to supply the fuel to the combustion chamber of each cylinder of the internal combustion engine; a delivery pipe for distributing fuel to the fuel injection valves; and a delivery of fuel from the fuel pressure adjusting means to the delivery pipe. A feed pipe provided for supply, and a fuel pressure fluctuation absorbing means attached to the delivery pipe and absorbing a fuel pressure fluctuation generated in the delivery pipe when the fuel injection valve injects fuel by an expansion action of a pressurized gas. wherein the fuel pressure fluctuation absorber means, wherein the membrane body made of an elastic material that the delivery pipe is divided into a fuel chamber and the damper chamber, pressurized gas sealed in the damper chamber and The fuel supply apparatus characterized by having a sexual fluid. 2. A fuel tank for storing fuel, a fuel pump for pressurizing and supplying fuel in the fuel tank, fuel pressure adjusting means for adjusting fuel from the fuel pump to a predetermined pressure, and a multi-cylinder. A plurality of fuel injection valves for injecting fuel to supply the fuel to the combustion chamber of each cylinder of the internal combustion engine; a delivery pipe for distributing fuel to the fuel injection valves; and a delivery of fuel from the fuel pressure adjusting means to the delivery pipe. A feed pipe provided for supply, and a fuel pressure fluctuation absorbing means attached to the delivery pipe and absorbing a fuel pressure fluctuation generated in the delivery pipe when the fuel injection valve injects fuel by an expansion action of a pressurized gas. Comprising, the fuel pressure fluctuation absorbing means, a hollow body made of an elastic material,
A fuel supply device comprising a pressurized gas and a viscous fluid sealed in the hollow body. 3. The fuel supply device according to claim 1, wherein the fuel pressure adjusting means is provided near the fuel tank or in the fuel tank.