JPH06221240A - Fuel supplying device for vehicle with sub engine - Google Patents

Abstract

PURPOSE:To provide a fuel supplying device, which can miniaturize a fuel tank for sub engine without hindering the stabilized fuel supply to the sub engine. CONSTITUTION:A sub fuel tank 4 is interposed in a fuel return passage 5 of a main engine 1 of a vehicle with sub engine, and the fuel for a sub engine 2 is supplied from the sub fuel tank 4. Since the excessive fuel of the main engine 1 is supplied to the sub fuel tank 4 ordinarily, even when the sub fuel tank 4 is miniaturized, the stabilized fuel supply to the sub engine 2 is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for a vehicle having a main engine and a sub engine.

[0002]

2. Description of the Related Art In addition to a main engine for driving a vehicle such as a vehicle having auxiliary equipment such as a water pump or an air conditioner, such as a fire engine or water sprinkler with a water pump or a large bus with an air conditioner, an auxiliary equipment drive There is a special vehicle equipped with a sub engine for.

In such a special vehicle, it is known that fuel for driving the sub engine is supplied from a main fuel tank for driving the main engine, or is supplied from a separately installed fuel tank. There is.

FIG. 3 is an overall view showing an example of a conventional apparatus for supplying fuel for driving a sub engine from a main fuel tank for driving a main engine. In this conventional apparatus, fuel is supplied to the main engine 1 and the sub-engine 2 from the main fuel tank 3 through the fuel supply passages 9 and 6 branched from one fuel supply passage. Excess fuel in the main engine 1 and the sub engine 2 is returned to the main fuel tank 3 through the respective fuel return passages 5 and 7.

FIG. 4 is an overall view showing an example of a conventional device for supplying fuel for driving a sub engine from a separately installed fuel tank. In this conventional apparatus, fuel is supplied to the main engine 1 and the sub engine 2 from independent fuel tanks. Fuel is supplied to the main engine 1 from the main fuel tank 3 through the fuel supply passage 9, and excess fuel is returned to the main fuel tank 3 through the fuel return passage 5. Fuel is supplied to the sub-engine 2 from the separate fuel tank 12 through the fuel supply passage 6.
The surplus fuel is returned to the separate fuel tank 12 through the fuel return passage 7.

[0006]

However, in the device of FIG. 3, there is a problem of the distribution ratio of the fuel flow rate, and depending on the usage situation, sufficient fuel is not supplied to the sub-engine 2, resulting in the output of the water pump. There may be a shortage or a problem such as deterioration of the efficiency of the air conditioner, and in order to secure sufficient fuel, the diameter of the feed line 9 must be increased, and the main fuel tank for a vehicle that drives only the main engine 1 No. 3 cannot be used, and a dedicated fuel tank is required for a vehicle with a sub engine, which increases the cost. Further, in the apparatus of FIG. 4, the remaining fuel amount in the two fuel tanks 3 and 12 must be checked, and refueling must be performed separately. Further, since the separate fuel tank 12 needs to have a size corresponding to the amount of fuel used by the sub-engine 2, there is a problem in that a space must be secured accordingly and design restrictions are imposed.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a fuel supply device for a vehicle with a sub-engine which rationally solves the above problems.

[0008]

A fuel supply system for a vehicle with a sub-engine according to the present invention comprises a main engine for driving a vehicle and a sub-engine for driving an auxiliary machine, wherein both engines use the same quality fuel. A main fuel tank for supplying fuel to the main engine, a sub fuel tank interposed in a part of a fuel return passage for returning surplus fuel of the main engine to the main fuel tank, and the sub engine from the sub fuel tank. And a sub-engine fuel supply passage for supplying fuel to the sub-engine.

[0009]

The fuel used in the sub engine is supplied from the sub fuel tank, and the surplus fuel of the main engine is always supplied to the sub fuel tank.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel supply system for a vehicle with a sub engine to which the present invention is applied will be described in detail with reference to FIG.

In this embodiment, the parts substantially the same as those of the conventional device described above are designated by the same reference numerals as those used above.

The main engine 1 is an engine for running a vehicle, the sub engine 2 is an engine for driving auxiliary equipment such as a water pump or an air conditioner, and both engines 1 and 2 use the same quality of fuel. . The fuel feed pump 10 for supplying fuel to the fuel injection pump 13 of the main engine 1 and the fuel filter 17 are provided in the fuel supply passage 9
Is communicated with the main fuel tank 3. The fuel return passage 5 for returning the surplus fuel of the fuel injection pump 13 to the main fuel tank 3 is communicated with the sub fuel tank 4, and the sub fuel tank 4
The main fuel tank 3 is communicated with the main fuel tank 3 by a fuel return passage 8.

On the other hand, the fuel injection pump 1 of the sub engine 2
The fuel feed pump 11 for supplying fuel to the fuel tank 4 and the fuel filter 18 communicate with the sub fuel tank 4 and the fuel supply passage 6. The fuel return passage 7 of the sub engine 2 for returning the surplus fuel of the fuel injection pump 14 to the main fuel tank 3 is communicated with the main fuel tank 3.

Refueling of the vehicle employing this embodiment is performed by refueling only the main fuel tank 3 from the fuel inlet 15, and the fuel supply to the main engine 1 and the sub engine 2 is as follows. It is done as follows.

That is, fuel is supplied to the main engine 1 from the fuel tank 3 by the fuel feed pump 10 through the fuel supply passage 9. Further, in the main engine 1, fuel is injected into each cylinder by the fuel injection pump 13,
The surplus surplus fuel is sent to the sub fuel tank 4 through the fuel return passage 5. Therefore, the surplus fuel of the main engine 1 is always supplied to the sub fuel tank 4. Fuel is supplied to the sub engine 2 from the sub fuel tank 4 by the fuel feed pump 11 through the fuel supply passage 6. In the sub engine 2, the excess fuel injected into each cylinder by the fuel injection pump 14 and remaining surplus fuel is supplied to the fuel return passage 7
It is returned to the main fuel tank 3. Further, the fuel exceeding the capacity in the sub fuel tank 4 is returned to the main fuel tank 3 through the fuel return passage 8.

Since the surplus fuel of the main engine is constantly supplied to the sub fuel tank 4, the sub fuel tank 4
The capacity of is set to a small value within a range where the sub engine 2 does not cause an output shortage. In other words, the capacity of the sub fuel tank 4 is set in consideration of the operating condition of the main engine 1 so that the surplus fuel of the main engine can be stored so that the fuel required by the sub engine can always be supplied.

Further, in this embodiment, the main fuel tank 3 and the sub fuel tank 4 are provided with the same air breather as the normal fuel tank, but the air breather may be omitted for the sub fuel tank 4.

Another embodiment is shown in FIG. Sub fuel tank 4
Is installed at a position lower than the main fuel tank 3, and due to this height difference, fuel is also supplied from the main fuel tank 3 directly to the sub fuel tank 4 via the fuel return passage 8. That is, since the fuel is supplied to the sub fuel tank 4 regardless of the operating condition of the main engine 1, the capacity of the sub fuel tank 4 can be further reduced as compared with the above embodiment.

In this embodiment, the main fuel tank 3 is provided with an air breather, but the sub fuel tank 4 is
Since it is located lower than the main fuel tank 3, no air breather is provided.

In the above two embodiments, the fuel return passage 7 of the sub engine is connected to the fuel return passage 8 from the sub fuel tank or the fuel return passage 5 of the main engine. 7 may be directly opened to the main fuel tank 3. However, in this case, it is necessary to drill the main fuel tank 3.

According to the above embodiments, the main engine 1
Since the surplus fuel is supplied to the sub-engine 2 via the sub-fuel tank 4, the fuel used in the sub-engine 2 is sufficiently secured and the output of the sub-engine 2 can be stabilized.

Further, it is sufficient to install the auxiliary fuel tank 4 having a small capacity without installing the separate fuel tank 12 having a large capacity as in the conventional apparatus, and the space limitation is greatly improved.

The present invention is not limited to the engine with a fuel injection pump described above, but can be applied to other engines with a carburetor or the like.

[0024]

According to the present invention, the fuel used in the sub-engine is supplied from the sub-fuel tank and the surplus fuel of the main engine is constantly supplied to the sub-fuel tank. Sufficiently secured, the output of the sub engine can be stabilized with the main fuel tank as it is, and the sub fuel tank can be made significantly smaller than the separate tank in the conventional device, so there is also a space constraint on the design. It is possible to provide a significantly improved fuel supply device for a vehicle with a sub-engine.

[Brief description of drawings]

FIG. 1 is an overall view of a fuel supply device for a vehicle with a sub engine according to an embodiment of the present invention.

FIG. 2 is an overall view of a fuel supply device for a vehicle with a sub engine according to another embodiment of the present invention.

FIG. 3 is an overall view showing an example of a conventional device.

FIG. 4 is an overall view showing another example of a conventional device.

[Explanation of symbols]

 1 main engine 2 sub engine 3 main fuel tank 4 sub fuel tank 5 main engine fuel return passage 6 sub engine fuel supply passage 7 sub engine fuel return passage 8 fuel return passage from sub fuel tank 9 main engine fuel supply Passage 10 Fuel feed pump for main engine 11 Fuel feed pump for sub engine 12 Separate fuel tank 13 Fuel injection pump for main engine 14 Fuel injection pump for sub engine 15, 16 Fuel injection port 17, 18 Fuel filter

Claims (1)

[Claims] 1. A main fuel tank for supplying fuel to the main engine in a vehicle having a main engine for driving a vehicle and a sub-engine for driving auxiliary equipment, wherein both engines use fuel of the same quality, and the main engine. A sub-fuel tank interposed in a part of the fuel return passage for returning the surplus fuel to the main fuel tank, and a sub-engine fuel supply passage for supplying fuel from the sub-fuel tank to the sub-engine. Characteristic fuel system.