JPH0212296Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a fuel supply system for an internal combustion engine, and particularly relates to a system for supplying fuel to an engine from a fuel tank in which two fuel reservoir spaces are independently formed. .

<Prior art> For example, there is a fuel supply device as shown in Utility Model Application Publication No. 167956/1983, in which a fuel pump is installed inside the fuel tank and the fuel is supplied under pressure to the engine outside the tank. . Furthermore, a fuel level gauge, such as a float lever type, is installed in the fuel tank to detect the remaining amount of fuel.

<Problems to be Solved by the Invention> By the way, when the bottom wall of the fuel tank is substantially flat, fuel supply and remaining fuel amount detection can be performed without problems with one fuel pump. However, like the fuel tanks installed in recent low-floor vehicles, a part of the bottom wall protrudes upward to avoid interference with the propeller shaft, and two fuel storage spaces are formed independently on both sides of the bottom wall. In such a configuration, if a fuel pump is provided in each space to supply fuel from the two fuel storage spaces, the cost will increase.

For this reason, it is conceivable that a single fuel pump has two fuel suction passages connected to its fuel suction port to simultaneously suck fuel from two fuel reservoir spaces and supply fuel to the engine.

However, in this case, when the remaining amount of fuel in the two fuel storage spaces decreases, the fuel in one fuel storage space may run over the protruding part of the bottom wall due to turning operation of the vehicle, etc., and enter the other fuel storage space. The amount of fuel remaining in the two fuel storage spaces becomes different due to the movement of the fuel into the fuel storage space. For this reason, one of the fuel reservoir spaces becomes empty first, causing the fuel pump to suck in air, and even if there is sufficient fuel remaining in the other fuel reservoir space, fuel cannot be sucked in. The problem arises that it becomes impossible to do so.

This idea was created in view of the above-mentioned circumstances.
It is an object of the present invention to provide a fuel supply device for an internal combustion engine that can maintain the remaining amounts of two fuel reservoir spaces equally with one fuel pump and supply fuel satisfactorily until the remaining amount reaches approximately zero. shall be.

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. In a fuel supply system for an internal combustion engine, a bifurcated fuel suction passage selectively communicates with the fuel suction port of one fuel pump B and the two fuel reservoir spaces via an electromagnetic switching valve C. D is installed, and a remaining fuel amount detection means E is provided in each of the two fuel storage spaces,
and a remaining amount comparing means F for comparing the respective remaining fuel amounts in the two fuel reservoir spaces detected by these two remaining fuel amount detecting means E, and a remaining amount comparing means F for comparing the respective remaining fuel amounts in the two fuel reservoir spaces detected by these two remaining fuel amount detecting means E, and a The valve switching control means G is provided to switch and control the electromagnetic switching valve C so that the fuel suction port communicates with the fuel reservoir space with a larger amount of remaining fuel.

<Operation> With this configuration, the remaining fuel amounts in the two fuel reservoir spaces in the fuel tank are detected by the two remaining fuel amount detection means, and the magnitudes thereof are compared by the comparison means. Then, based on this comparison signal, switching control is performed by the valve switching control means so that the fuel reservoir space with a large amount of remaining fuel communicates with the fuel suction port of the fuel pump, and as a result, the remaining amount of fuel is always large. Fuel is supplied from the fuel storage space on the other side.

Therefore, in order to keep the remaining amount of fuel in the two fuel storage spaces equal, fuel is alternately supplied from the two fuel storage spaces, and the fuel is kept well until the remaining amount of fuel in the fuel tank becomes approximately zero. Supply is made.

<Example> Hereinafter, an example of the present invention will be described based on FIG. 2.

A fuel tank 1 mounted on a low-floor vehicle has a center portion of the bottom wall that protrudes upward to avoid interference with the propeller shaft, and fuel storage spaces 1a and 1b on both sides of the bottom wall.
are formed independently.

A fuel pump 2 is mounted inside the fuel tank 1 via a bracket fixed to the top wall of the tank. An inlet port of an electromagnetic switching valve 3 is connected to a fuel suction port 2a formed at the lower end of the fuel pump 2, and two outlet ports at both ends of the electromagnetic switching valve 3 are connected to the fuel reservoir spaces 1a and 1b, respectively. Fuel suction passages 4A and 4B are connected thereto. A filter 5 is provided at the lower end of the fuel intake passages 4A, 4B.
A and 5B are attached.

A discharge port of the fuel pump 2 is connected to a fuel injection valve of an engine (not shown) via a fuel supply passage 6 that penetrates the top wall of the tank while maintaining a sealing property.

Further, two fuel level gauges 7A and 7B are installed as fuel level detection means for detecting the level of fuel remaining in each of the fuel reservoir spaces 1a and 1b. this is,
For example, as shown in the figure, a lever with a float fixed to the tip that floats on the fuel liquid level is pivoted to freely move up and down, and a potentiometer is used to detect the amount of swing of the lever, that is, the amount of remaining fuel corresponding to the fuel level. is used.

The remaining amount detection signals from each of the fuel remaining amount gauges 7A and 7B are input to a control unit 8 having a built-in microcomputer, and the control unit 8 receives the two remaining amount detection signals using the software function of the microcomputer. The electromagnetic switching valve 3 is switched and driven so as to determine which fuel reservoir space has a larger amount of fuel remaining, and to communicate the fuel suction passage on the side of this fuel reservoir space with the fuel suction port 2a of the fuel pump 2. do.

FIG. 3 is a flowchart showing the control by the control unit 8. To explain it according to this flowchart, in step 1 (indicated as S1 in the figure, the same goes for the others), and in step 2, each of the remaining fuel gauges 7A and 7B is Then, read the detected remaining fuel amount.

In step 3, the remaining fuel amounts are compared, and if the fuel reservoir space 1a is larger, the process proceeds to step 4, where the electromagnetic switching valve 3 is changed so that the fuel suction port 2a communicates with the fuel suction passage 4A. If the fuel storage space 1b is larger, step 5
Then, the electromagnetic switching valve 3 is switched and driven so that the fuel suction port 2a communicates with the fuel suction passage 4B. Here, step 3 corresponds to the remaining amount comparison means,
Steps 4 and 5 correspond to the valve switching control means.

With such a configuration, fuel is always supplied from the fuel reservoir space on the side with a larger amount of fuel remaining, so the amount of fuel remaining in the two fuel reservoir spaces may temporarily differ due to turning movement of the vehicle, etc. In order to eliminate this difference, fuel is supplied so that the remaining amount of fuel is the same, so the two fuel storage spaces 1a and 1
Fuel can be supplied satisfactorily until both the remaining fuel amounts in b become approximately zero. Moreover, the fuel pump is 1
Since only one piece is required, costs can be reduced as much as possible.

In addition, it is necessary to provide two fuel level gauges 7A and 7B in any case (even if there are two fuel pumps), and the remaining fuel level is indicated by averaging the two detected values. It turns out. In this case, if fuel is supplied while constantly maintaining the remaining amount of fuel in the two fuel reservoir spaces 1a and 1b at approximately the same level as in the present invention, the cross-sectional area of the fuel reservoir space can be reduced in the depth direction. Since the two detected values are substantially the same even when the amount changes, the remaining amount can be measured with higher accuracy.

<Effects of the invention> As explained above, according to the invention, fuel is supplied to the one with a larger amount of fuel remaining in the two independent fuel storage spaces of the fuel tank. As in the case of a tank, fuel supply can be continued satisfactorily until the remaining fuel level approaches zero, and since only one fuel pump is required, it can be implemented at low cost. It also has various advantages, such as being able to measure the remaining amount of fuel with high precision.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention;
The figure is a configuration diagram showing the configuration of an embodiment of the present invention.
The figure is a flowchart showing the control operation of the embodiment. 1...Fuel tank, 1a, 1b...Fuel reservoir space, 2...Fuel pump, 2a...Fuel suction port, 3
... Solenoid switching valve, 4A, 4B ... Fuel intake passage,
6...Fuel supply passage, 7A, 7B...Remaining fuel gauge, 8...Control unit.

Claims (1)

[Scope of utility model registration request] A fuel supply device for an internal combustion engine that supplies fuel to an engine from a fuel tank in which a part of the bottom wall projects upward to form two independent fuel reservoir spaces,
A bifurcated fuel suction passage that selectively communicates with the two fuel reservoir spaces is installed at the fuel suction port of one fuel pump via an electromagnetic switching valve, and the remaining amount of fuel is maintained in each of the two fuel reservoir spaces. a detecting means, a remaining amount comparing means for comparing the respective remaining fuel amounts in the two fuel reservoir spaces detected by these two remaining fuel amount detecting means, and a fuel pump based on a signal from the comparing means. 1. A fuel supply device for an internal combustion engine, comprising valve switching control means for switching and controlling an electromagnetic switching valve so as to communicate a fuel suction port with a fuel reservoir space having a larger amount of remaining fuel.