JP2000257525A - Fuel supply unit for fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply unit for a fuel injection device having a simple structure, constituted in a compact manner, and capable of separating and removing vapor in fuel actively. SOLUTION: In a fuel supply unit supplying the fuel discharged by a fuel pump 5 in a fuel chamber 4 arranged on a lower side of a fuel tank to a fuel injection device by controlling pressure by a fuel pressure regulator 9, a jet pump 12 is provided in a fuel return passage returning fuel from the fuel pressure regulator 9 into the fuel tank, and communicating passages 1a, 1b communicating an upper part in the fuel chamber 4 with a negative pressure chamber 11 of the jet pump 12 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact fuel supply unit provided on a fuel passage connected to a fuel tank and a fuel injection device of an internal combustion engine, and particularly capable of easily separating and removing vapor.

[0002]

2. Description of the Related Art In recent years, modularization of a fuel supply device has been advanced in motorcycles and the like in order to improve assemblability and reduce costs. When an inexpensive, low-pulsation, low-vibration, low-noise turbine type pump is used for this fuel supply device, it is necessary to immerse the pump suction port in the fuel because the suction pressure of the pump is low. Also, if the fuel pump sucks air or vapor, the required fuel will not be injected, and the operation of the engine will become unstable, possibly causing the engine to stop.Therefore, the air in the fuel, the heat from the fuel pump or the engine, or the engine It is necessary to remove the vapor generated by the vibration from the fuel chamber.

An example of a fuel supply unit configured to discharge vapor or air in fuel from a fuel chamber as proposed in US Pat. No. 5,647,331 will be described with reference to FIG. Upper and lower casings 17 shown in the figure,
17 are combined to form the fuel chamber 4.

Fuel is supplied to the fuel chamber 4 from a fuel tank 18 via a liquid level control valve 16. The fuel flows from the fuel tank 18 into the fuel chamber 4 by gravity.

The suction port 5a of the fuel pump 5 disposed in the fuel chamber 4 is immersed in the fuel. The fuel discharged from the fuel pump 5 is sent to the fuel passage 17a, and is sent from the nipple 13 provided in the fuel passage 17a to the fuel distribution pipe.

[0006] The fuel pressure regulator 9 having an inlet opening to the fuel flow path 17a returns excess fuel to the fuel chamber 4 so that the pressure in the fuel flow path 17a becomes constant. In this way, the pressure of the fuel sent to the fuel distribution pipe is kept constant,
The fuel distributed from the fuel distribution pipe to the fuel injection device is supplied to the engine at a controlled flow rate.

[0007] Vapor and air generated from the fuel in the fuel chamber 4 accumulate on the fuel in the fuel chamber, and when the pressure exceeds a certain level, is sent to the intake manifold of the engine through the back pressure valve 15.

[0008]

In the above-mentioned conventional fuel supply unit, a liquid level control valve for controlling the liquid level in the fuel chamber to a constant level, and vapor and air accumulated on the fuel in the fuel chamber are discharged. A back-pressure valve is required, and the structure becomes complicated. Further, there is a problem that the unit becomes large because a considerable space for storing vapor and air is required above the fuel pool.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a fuel supply unit for a fuel injection device which has a simple structure and a compact structure, and can actively separate and remove vapor in fuel. Is to provide.

[0010]

A fuel supply unit of a fuel injection device according to the present invention controls the pressure of fuel discharged from a fuel pump in a fuel chamber disposed below a fuel tank by a fuel pressure regulator. In a fuel supply unit for supplying to the apparatus, a jet pump is provided in a fuel return flow path that returns fuel from the fuel pressure regulator to a fuel tank, and a communication path that communicates an upper part in the chamber and a negative pressure chamber of the jet pump is provided. It is something.

Further, in the fuel supply unit of the fuel injection device, a high-pressure fuel filter for filtering fuel discharged from a fuel pump is provided in the fuel chamber.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel supply unit of a fuel injection device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a fuel supply unit of a fuel injection device according to an embodiment of the present invention. The right housing 1, the center housing 2 and the left housing 3 shown in the figure are combined via an O-ring to form a space filled with fuel.

A central housing 2 and a right housing 1 surround a fuel chamber 4.
A fuel pump 5 of a turbine type is disposed therein. Note that the suction port 5 a of the fuel pump 5 is located at a low place in the fuel chamber 4.

Nipple 6 attached to right housing 1
, A nipple 6 is connected to a fuel tank (not shown), and fuel flows from the fuel tank into the fuel chamber 4 through the low-pressure fuel filter 7 and the nipple 6 by gravity.

When power is supplied to the fuel pump 5 through the connector 14, the fuel pump 5 feeds fuel into a space surrounded by the left housing 3. The high-pressure fuel passes through the ring-shaped high-pressure fuel filter 8 to remove dust, and then flows into the high-pressure chamber 2b surrounded by the central housing 2.

A fuel pressure regulator 9 connected to the high-pressure chamber 2b regulates the flow rate of the fuel returned to the fuel tank through the throttle pipe 10, the negative pressure chamber 11, and the nipple 13 to keep the pressure of the fuel in the high-pressure chamber 2b constant. To control. The fuel whose pressure is kept constant in this way is sent to the fuel distribution pipe from the discharge hole 2a opened in the high-pressure chamber 2b, and further supplied to the engine with the flow rate controlled by the fuel injection device.

Next, the jet pump 12 constituted by the throttle pipe 10 and the negative pressure chamber 11 will be described. In the upper part of the fuel chamber 4, a communication path for communicating the negative pressure chamber 11 of the jet pump 12 with the upper part in the fuel chamber is formed by the communication holes 1 a and 1 b through the space around the throttle pipe 10. The jet pump 12 sucks the fuel around the throttle pipe 10 by the high-speed flow throttled by the nozzle, and returns the fuel to the fuel tank together with the high-speed flow. As a result, fuel flows upward through the communication holes 1a and 1b, and the vapor and air generated in the fuel chamber 4 by this flow are positively returned to the fuel tank.

In this embodiment, the communication holes are provided at two places. However, any number of communication holes may be provided as long as the communication holes are provided above the fuel chamber so as to be sucked by the jet pump.

As described above, the upward flow returning to the fuel tank is generated in the fuel chamber 4, so that the air and the vapor are reliably discharged, and the fuel pump 5 does not suck the air and the vapor. Further, the fuel pump 5 can be effectively cooled by the flow of the fuel in the fuel chamber 4.

[0020]

As described above, according to the fuel supply unit of the fuel injection device of the present invention, the vapor or air in the fuel chamber 4 is forcibly discharged by the flow returning to the fuel tank, so that a stable fuel supply can be achieved. Supply becomes possible.

In the supply of fuel into the fuel chamber, the flow of the fuel due to its own weight is increased by the flow returning to the fuel tank, and the fuel circulation in the fuel chamber is promoted, so that the fuel pump is effectively cooled. Generation of vapor due to heat is suppressed.

Further, unlike the prior art described with reference to FIG. 2, the liquid level control valve and the back pressure valve are not required, so that the structure is simplified and the space for separating the vapor is not required, so that the apparatus can be downsized. it can.

Since the jet pump uses the pressure of the surplus fuel from the fuel pressure regulator, the device can be made more compact by not requiring a new energy source.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a fuel supply unit of a fuel injection device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a fuel supply unit of a conventional fuel injection device.

[Explanation of symbols]

Reference Signs List 1 right housing, 1a, 1b communication hole 2 central housing, 2a discharge hole, 2b high pressure chamber 3 left housing 4 fuel chamber 5 fuel pump, 5a suction port 6 nipple 7 low pressure fuel filter 8 high pressure fuel filter 9 fuel pressure regulator 10 throttle pipe 11 Negative pressure chamber 12 Jet pump 13 Nipple 14 Connector 15 Back pressure valve 16 Liquid level control valve 17 Casing, 17a Fuel flow path 18 Fuel tank

Claims (2)

[Claims] 1. A fuel supply unit for controlling the pressure of fuel discharged by a fuel pump in a fuel chamber disposed below a fuel tank by a fuel pressure regulator and supplying the fuel to a fuel injection device, wherein the fuel is supplied from the fuel pressure regulator to the fuel tank. A jet pump is provided in the fuel return flow path for returning fuel,
A fuel supply unit for a fuel injection device, further comprising a communication passage that communicates an upper portion of the chamber with a negative pressure chamber of the jet pump. 2. The fuel supply unit according to claim 1, wherein a high-pressure fuel filter for filtering fuel discharged from a fuel pump is provided in the fuel chamber.