JPS6167625A - Fuel tank for car - Google Patents

Abstract

PURPOSE:To prevent the mixing of gasoline with alcohol due to the vibration, etc. of a car and always maintain the both in certainly separated state by forming a small chamber in the bottom part of a fuel tank and separating the small chamber from the inside of the fuel tank by an alcohol separating membrane. CONSTITUTION:A small chamber 8 projecting downward is formed in the bottom part of a fuel tank 1 for storing gasoline containing alcohol, and the upper part of the small chamber 8 is covered by an alcohol separating membrane 9. Therefore, the alcohol in the mixed fuel poured into the fuel tank 1 is allowed to flow into the small chamber 8 through the separating membrane 9, and the gasoline having a large content of alcohol is stored into the small chamber 8. The bottom part of the fuel tank 1 is connected to a fuel injection valve 3 through a fuel feeding pipe 10, and a fuel feeding pump 11 and a fuel filter 12 are arranged in the fuel feeding pipe 10. While, the bottom part of the small chamber 8 is connected to an electromagnetic selector valve 16 through an alcohol feeding pipe 15, and said selector valve 16 is connected to the fuel injection valve 3 through a flow-rate control valve 20.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vehicle fuel tank used for alcohol-mixed fuel.

Conventional technology Gasoline and alcohol are phase-separated in the fuel tank due to the difference in specific gravity. Under normal conditions, gasoline is sucked from the fuel tank and supplied into the engine cylinder. When knocking occurs, alcohol is sucked from the fuel tank. An internal combustion engine is known in which the occurrence of non-king is suppressed by supplying fuel into the engine cylinder, as described in Japanese Patent Laid-Open No. 57-181957.

Problems to be Solved by the Invention However, when gasoline and alcohol are separated simply by the difference in specific gravity, vibrations of the vehicle cause the gasoline and alcohol to mix, making it impossible to reliably separate gasoline and alcohol. The problem is that it cannot be done.

Means for Solving the Problems In order to solve the above problems, according to the present invention, a small chamber is formed at the bottom of the fuel tank, and the small chamber and the inside of the fuel tank are separated by an alcohol separation membrane.

Embodiment Referring to FIG. 1, 1 is a fuel tank for storing alcohol-containing gasoline, that is, alcohol mixed fuel, 2 is an engine body, 3 is a fuel injection valve disposed in an intake passage 4, and 5 is a fuel tank for storing alcohol-containing gasoline, that is, alcohol mixed fuel. 6 represents a spark plug, 6 represents a distributor, and 7 represents an igniter.

The fuel tank 1 has a small chamber 8 projecting downward at its bottom, and the upper part of the small chamber 8 is covered with an alcohol separation membrane 9. That is, the small chamber 8 and the inside of the fuel tank 1 are separated by the alcohol content: Miyabi 9.

The alcohol separation membrane 9 is, for example, a porous ceramic with open cells coated with cellulose triacetate. When the alcohol mixed fuel is injected into the fuel tank 1, the alcohol in the alcohol mixed fuel quickly passes through the alcohol separation membrane 9 and is sent into the small chamber 8, so that the small chamber 8 contains gasoline with a high alcohol content. is stored.

The bottom of the fuel tank 1 is connected to the fuel injection valve 3 via a fuel supply pipe 10, within which a fuel supply pump 11 and a fuel filter 12 are arranged. A fuel supply pipe 10 downstream of the fuel filter 12 is connected to the fuel tank 1 via a fuel return pipe 13 and a pressure regulator 14 . When the engine starts, the fuel supply pump 11 is driven, and fuel at a constant pressure regulated by the pressure regulator 14 is supplied to the fuel injection valve 3. On the other hand, the bottom of the small chamber 8 is connected to an electromagnetic switching valve 16 via an alcohol supply pipe 15, and an alcohol supply pump 17 and a filter 18 are disposed inside this alcohol supply pipe 15. An alcohol detector 21 for detecting the presence or absence of alcohol is installed in the small chamber 8, which is connected to the small chamber 8 via an alcohol return pipe 19 and connected to the fuel injection valve 3 via a flow control valve 20 on the other hand. A knocking detector 22 for detecting the occurrence of knocking is attached to the engine body 2. This non-king detector 22 continues to output a knocking occurrence signal as long as knocking occurs.

The electronic control unit 30 consists of a digital computer with ROMs interconnected by a bidirectional bus 31.
(Read-only memory) 32, RAM (Random access memory) 33, CPIJ (MacroCroproceno+)
) 34, an input port 35 and an output port 36. The input port 35 is connected to an air flow meter 37 that detects the amount of intake air, a rotation speed sensor 38 that detects the engine speed, an alcohol detector 21 and a non-king detector 22, and an output port 36 is connected to the igniter 7 and the electromagnetic switching valve 16.
, the alcohol supply pump 17 and the flow control valve 20.

Next, the fuel supply control method will be explained with reference to the flowchart shown in FIG.

First, in step 40, the alcohol detector 21
It is determined whether or not there is alcohol in the small chamber 8 based on the output signal of 5600, and then in step 42, it is determined from the output signals of the air flow meter 17 and the rotation speed sensor 38 that the intake air amount Q/engine rotation speed N is a set value, for example, Q/N≧0.55j.
l! Determine whether or not. If the above conditions are not met, proceed to step 43 and turn on the alcohol supply pump 17.
If the above three conditions are satisfied, the process proceeds to step 44 and the alcohol supply pump 44 is activated.

When the alcohol supply pump 44 is activated, the small chamber 8
The alcohol inside is supplied through alcohol supply pipe 15 and electromagnetic switching valve 1.
6 and the alcohol return pipe 19 into the small chamber 8.

In step 45, it is determined from the output signal of the knocking detector 22 whether or not non-king is occurring. If knocking is occurring, the process proceeds to step 46, where the electromagnetic switching valve 16 is energized. tWhen the M1 switching valve 16 is activated, alcohol is supplied to the fuel injection valve 3 via the flow control valve 20.Next, in step 47, for example, the flow control valve 2 is supplied to the fuel injection valve 3 via the flow control valve 20.
A constant value α is added to the duty ratio of the solenoid drive pulse added to 0. Then, in step 4B, the duty ratio is Dmax = 1, that is, the flow rate control valve 2
It is determined whether or not the 0 is fully opened. It can be seen that the routine shown in Figure 2 is executed at a constant time interrupt, and therefore, as long as knocking occurs, the duty ratio is gradually increased and the alcohol supply amount is gradually increased. .

If the flow rate control valve 20 is fully opened but notching still occurs and ζ occurs, the process proceeds to step 49 to set D-Dmax, and then, in step 50, the ignition advance amount θ is delayed by β. Steps 51 and 52 are guards to prevent the ignition advance amount θ from becoming smaller than a predetermined constant value. Therefore, as long as knocking occurs,
The ignition advance amount θ is decreased toward a constant value A. When nogging occurs in this manner, the alcohol supply amount is first increased, and if knocking still occurs even after the flow control valve 20 is fully opened, the ignition timing is retarded.

When the occurrence of non-king stops, the duty ratio of the solenoid drive pulse of the flow control valve 20 is subtracted by α in step 53, and then in step 54 it is determined whether the duty ratio is D≦0, that is, the duty ratio of the flow control valve 20 is subtracted by α.
It is determined whether or not it is fully closed. Therefore, when the occurrence of knocking stops, the flow rate control valve 20 is gradually closed. When the flow rate control valve 20 is fully closed, the process proceeds to step 55, where the duty ratio is made zero, and then, in step 56, the electromagnetic switching valve 56 is deenergized to stop the supply of alcohol to the fuel injection valve 3. Next, in step 57, the ignition advance amount θ is added by a constant value β. In step 58, it is determined whether the ignition advance amount θ is smaller than the optimum ignition advance amount θ0, and if θ>θ6, the ignition advance amount θ is set to the optimum ignition advance amount θ0 in step 59. When the occurrence of oxidation stops in this manner, the supply amount of alcohol is first gradually reduced, and then the ignition advance amount θ is gradually increased to the optimum advance amount θ0.

Effects of the Invention Since the inside of the fuel tank and the small chamber are separated by an alcohol separation membrane, once alcohol and gasoline are separated, they do not mix with each other due to vehicle vibrations, etc. Therefore, alcohol is constantly separated. can be reliably maintained.

Furthermore, since it is only necessary to provide a small chamber below the bottom wall of the fuel tank, there is an advantage that the fuel tank can be made smaller.

[Brief explanation of drawings]

FIG. 1 is an overall view of the fuel supply system, and FIG. 2 is a flowchart. 1... Fuel tank, 2... Engine body, 3...
Fuel injection valve, 5... Spark plug, 8... Small chamber,
9...Alcohol separation membrane, 10...Fuel supply pipe, 15...Alcohol supply pipe, 1°6
...Solenoid switching valve, 17...Alcohol supply pump, 30...Electronic control unit.

Claims (1)

[Claims] A fuel tank for a vehicle in which a small chamber is formed at the bottom of the fuel tank, and the small chamber and the inside of the fuel tank are separated by an alcohol separation membrane.