JPH02211372A - Engine fuel supply system - Google Patents

Abstract

PURPOSE:To improve the starting performance of an engine by judging if the alcohol-mixed fuel is supplied into a fuel tank or not and charging the new fuel into a fuel injection valve from a fuel pipe by driving a fuel injection pump for a certain time if fuel is supplied and by controlling the fuel injection quantity to a proper value on the first start of the engine after fuel feed. CONSTITUTION:A fuel pump 14 supplies alcohol-mixed fuel into a fuel injection valve 9 through a fuel pipe 7. A residual quantity sensor for detecting the residual quantity of the alcohol-mixed gasoline stored in a fuel tank 4 is installed onto the fuel pump 14. The completion of the fuel feeding work is judged, and if the new alcohol-mixed gasoline is supplied, the new alcohol-mixed fuel is supplied into the fuel injection valve 9 from the fuel pipe 7 by driving the fuel pump 14. Therefore, the alcohol-mixed gasoline which is left in the fuel injection valve 9 from the pipe 7 is mixed into the new alcohol-mixed gasoline.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel supply device for an engine that supplies alcohol mixed fuel in a fuel tank to a fuel injection valve of an engine.

BACKGROUND ART Recently, alcohol-mixed gasoline, which is a mixture of gasoline and alcohol, has been used in various countries. Since genuine gasoline and alcohol-mixed gasoline naturally have different octane numbers, the amount of fuel injection and ignition timing for the engine will also differ. Therefore, when we look at the fuel injection amount T when using genuine gasoline, we find that T
I=Tp
``'(1) However, TP Two basic injection amounts α : Air-fuel ratio feedback correction coefficient α : Basic air-fuel ratio learning correction coefficient CoEF = Various correction coefficients Ts : Calculated as battery voltage correction coefficient. At this time, the oxygen from the oxygen sensor By correcting the air-fuel ratio feedback correction coefficient α based on the concentration signal, and learning correction of the basic air-fuel ratio learning correction coefficient α′ from the basic injection amount Tp and the number of engine rotations N,
The air-fuel ratio (weight ratio of air and fuel) A/F is controlled to be 15:1.

In this way, the air-fuel ratio A/F of genuine gasoline is 15:1, but the air-fuel ratio of alcohol-mixed gasoline has the characteristics as shown in Figure 5, and when the alcohol concentration is 100%, the air-fuel ratio is 6:1. It is known that

Therefore, when using alcohol-mixed gasoline,
From equation (1), calculate the fuel injection amount T+', T+ = Cl1 x
Tp XaXa XCozr÷T *-(2) However, CK: It is necessary to calculate as a constant determined by the alcohol concentration.

Here, as an alcohol sensor for detecting the alcohol concentration in alcohol-mixed gasoline, a resistance-type alcohol sensor that detects the alcohol concentration from the specific resistance value of gasoline and alcohol is being considered. As shown in FIG. 6, this resistance type alcohol sensor has a pair of electrodes S and C disposed facing each other at a predetermined distance apart from each other in the middle of a pipe A serving as a flow path, and a pair of electrodes S and C are interposed between the electrodes S and C. Based on the fact that the alcohol concentration of the alcohol-mixed gasoline d is high (the resistance value decreases), the electrodes S, C and the voltage detection resistor e are connected in series to the DC power supply f, and the output derived from the voltage detection resistor e is Alcohol concentration is detected from changes in voltage E.

[Problem to be solved by the invention]

Incidentally, the electric power of the alcohol-mixed gasoline supplied into the fuel tank may change over time due to various factors such as metal ions precipitated from the fuel tank and fuel system parts, water content, and the like. Additionally, the alcohol concentration of alcohol-mixed gasoline may vary depending on the filling station.

For this reason, when filling the fuel tank with new alcohol-blended gasoline, the alcohol concentration of the old alcohol-blended gasoline and the new alcohol-blended gasoline will be different.
As shown in FIG. 7, the output voltage is different before and after refueling.

Therefore, immediately after refueling with new alcohol-mixed gasoline, old alcohol-mixed gasoline remains from the fuel pipe to the fuel injection valve, and the fuel injection valve injects old alcohol-mixed gasoline for a while. ,
Since the resistive alcohol sensor detects the alcohol concentration of new alcohol-mixed gasoline, it is unable to control the fuel injection amount appropriately and has the problem of poor engine startability immediately after refueling.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and provides an engine fuel supply device that allows the fuel injection valve to inject fresh alcohol-mixed fuel even immediately after refueling, thereby improving engine startability. The purpose is to provide.

[Means to solve the problem]

In order to solve the above-mentioned problems, the means of the present invention is configured to include: a fuel tank for storing alcohol mixed fuel; a refueling determining means for determining whether refueling work to the fuel tank is completed; A fuel pipe disposed between the fuel injection valve, a fuel pump that supplies the alcohol-mixed fuel in the fuel tank to the fuel injection valve via the fuel pipe, and the refueling determination means that determines whether the refueling operation is complete or not. and fresh fuel filling means that drives the fuel pump for a predetermined period of time when the fuel pump is determined to fill the alcohol mixed fuel filled in the fuel tank from the fuel pipe to the fuel injection valve.

[Operation] With this configuration, new alcohol mixed fuel is supplied from the fuel pipe to the fuel injection valve immediately after the alcohol mixed fuel is refueled. Therefore, the fuel injected by the fuel injection valve when the engine is first started after refueling is the same as the alcohol mixed fuel whose alcohol concentration is detected by the alcohol sensor, and the fuel injection amount can be controlled appropriately for the engine. .

【Example〕

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 4.

In FIG. 1, reference numeral 1 indicates an automobile that uses alcohol-mixed gasoline as fuel, and a refueling lid 2 is hinged to the rear part of the vehicle body IA of the automobile 1 so as to be openable and closable.

3 indicates a fuel supply system provided in the automobile 1. 4
A fuel tank constitutes the fuel supply system 3 and stores alcohol-mixed gasoline therein. A fuel filler cap 5 is removably attached to the fuel filler pipe 4A of the fuel tank 4.

Reference numeral 6 denotes a cap switch provided on the fuel filler pipe 4A, and the cap switch 6 detects the end of refueling the fuel tank 4 by operating as the fuel filler cap 5 is opened and closed. ing.

Reference numeral 7 indicates a fuel pipe, one end of which is connected to the discharge port side of a fuel pump 14, which will be described later, and the other end connected to a fuel injection valve 9 and a pressure regulator 10 provided in the engine 8.
The fuel filter 11. is connected to the inlet side of the fuel filter 11. An alcohol sensor 12 is provided. on the other hand,
The outflow side of the pressure regulator IO is a return pipe 13
It is connected to the fuel tank 4 via.

Here, the alcohol sensor 12 is for detecting the alcohol concentration in the alcohol-mixed gasoline flowing in the fuel pipe 7, and the alcohol sensor 12 includes:
For example, a resistive alcohol sensor shown in FIG. 6 may be used.

Further, 14 is a fuel pump provided in the fuel tank 4, and the fuel pump 14 supplies alcohol mixed fuel to the fuel injection valve 9 via the fuel pipe 7. 15 is a remaining amount sensor that detects the remaining amount of alcohol-mixed gasoline stored in the fuel tank 4;
is attached to the fuel pump 14, for example.

In the figure, reference numeral 16 denotes an intake manifold provided in the engine 8, and an intake filter 17 is provided at the tip of the intake manifold 16, and an air flow meter 18 is provided in the middle.

Next, in FIG. 3, reference numeral 19 denotes an arithmetic unit that constitutes the fuel supply system, and the arithmetic unit 19 includes a processing circuit such as a CPU, a ROM and a RAM as storage circuits, and an input/output circuit (all not shown). ), etc., is configured as a microcomputer. The input side of the arithmetic unit 19 is an engine switch 20 . Remaining amount sensor 15. It is connected to the cap switch 6, etc., and the output side is connected to the fuel pump 14. It is connected to an alarm 21 and the like that warns if the fuel injection valve 9 and fuel filler cap 5 have been forgotten to close. In addition, the arithmetic device 19
A program shown in FIG. 4 is stored in the ROM.

The present embodiment is constructed as described above, and its operation will now be described with reference to FIG. 4.

First, when the process starts, the engine switch 20 is read in step l, and the engine switch 2 is read in step 2.
Determine whether 0 is ON or not, and if it is OFF, step 3
, and read the cap switch 6. When the process moves to step 4 and it is determined that the fuel filler cap 5 is closed, the car l is only stopped, so step 1
Return to.

On the other hand, in step 2 mentioned above, the engine switch 20 is turned OFF.
If N, the cap switch 6 is read in step 5, and it is determined in step 6 whether or not the fuel filler cap 5 is opened. If the determination in step 6 is No, it means that the vehicle is running normally, so the process returns to step 1. On the other hand, if the determination in step 6 is YES, it is dangerous to refuel with the engine switch 20 turned on, so the engine 8 and fuel pump 14 are stopped in step 7.

In step 4 described above, it is determined that the fuel filler cap 5 is open,
When the engine 8 and fuel pump 14 are stopped in step 7, the fuel tank 4 is refilled. Then, in step 8, the output value of the remaining amount sensor 15 is read, and in step 9, it is determined whether or not the fuel has increased. When the determination is No, the fuel filler cap 5 has been opened, but the fuel supply is being prepared and actual fuel supply is not being performed, so the process returns to step 1. On the other hand, if YES is determined in step 9, this indicates that the refueling operation has started, so the process moves to step 10, where the output value of the remaining amount sensor 15 is read, and in step 11, it is determined whether or not the increase in fuel has stopped. judge. If the determination is NO, this indicates that refueling is in progress, so the process returns to step 10.

If YES is determined in step 11 described above, this indicates that the increase in fuel has stopped and the refueling operation has been completed, so the process moves to step 12, where the cap switch 6 is read, and in step 13, the fuel filler cap 5 is closed. Determine whether it is closed or not. When the determination in step 13 is No, the process moves to step 14, and after the refueling operation is completed, it is determined whether a certain period of time, for example 10 seconds, required for closing the refueling port cap 5 has elapsed. Then, in step 14, the process returns to step 12 and the cap switch 6 is read until a predetermined time period elapses. On the other hand, when the predetermined time has passed in step 14, the process moves to step 15, where the alarm 21 is activated to issue an alarm to prevent the car 1 from driving off with the fuel filler cap 5 open. Return to step 12.

Further, when the determination is YES in step 13 described above, the process moves to step 16 and the fuel pump 14 is driven to supply new alcohol-mixed gasoline stored in the fuel tank 4 from the fuel pipe 7 to the fuel injection valve 9 side. , be returned from return piping 13. Then, in step 17, it is determined whether a predetermined time T seconds, for example, 5 to 10 seconds, required for new alcohol-mixed gasoline to replace the old fuel and fill it from the fuel tank 4 to the fuel injection valve 9 has elapsed. judge. When the determination is No, the process returns to step 16 to continue driving the fuel pump 14, and when the determination is YES, the fuel pump 14 is stopped and the process is ended.

In this way, in the embodiment, it is determined whether or not the refueling operation has been completed in steps 11 and 13, and if new alcohol-mixed gasoline is supplied, the fuel pump 14 is driven in step 16. New alcohol mixed fuel is supplied from the fuel pipe 7 to the fuel injection valve 9. As a result, the old alcohol-mixed gasoline remaining in the fuel injection valve 9 from the fuel pipe 7 is mixed into the new alcohol-mixed gasoline. Therefore, the alcohol-mixed gasoline whose alcohol concentration is detected by the alcohol sensor 12 is the same as the fuel injected by the fuel injection valve 9, and the fuel injection amount can be controlled appropriately.

Further, in the embodiment, a cap switch 6 is provided which is activated by the opening/closing operation of the fuel filler cap 5, and when the cap switch 6 remains open for a certain period of seconds, the alarm 21 is activated to issue an alarm. , fuel leakage from the fuel tank 4 can be prevented.

In the embodiment, steps 11 and 13 are specific examples of the refueling detection means, and step 16 is a specific example of the new fuel filling means, but the present invention is not limited to these specific examples.

Further, in the embodiment, the cap switch 6 has been described as being provided on the fuel filler pipe 4A of the fuel tank 4, but it may be provided, for example, on the back surface of the fuel filler lid 2 of the vehicle body IA.

Furthermore, the alcohol sensor 12 is not limited to a resistive alcohol sensor, but may also be a capacitive alcohol sensor that uses changes in the dielectric constant of alcohol-mixed gasoline, or a capacitance-type alcohol sensor that detects alcohol concentration from the potential difference between a pair of electrodes immersed in alcohol-mixed gasoline. It is also possible to use a so-called indirect sampling type alcohol sensor for detection, or even an optical type alcohol sensor that utilizes changes in the amount of transmitted light.

〔Effect of the invention〕

The engine fuel supply device according to the present invention is as described above in detail, and determines whether or not the alcohol-mixed fuel has been supplied to the fuel tank, and when the fuel tank has been supplied, drives the fuel injection pump for a certain period of time. Since the new fuel is configured to be filled into the fuel injection valve from the fuel pipe, it is possible to realize appropriate control of the fuel injection amount when starting the engine for the first time after refueling, and the startability of the engine can be improved.

[Brief explanation of the drawing]

Figures 1 to 4 relate to embodiments of the present invention, in which Figure 1 is an external view of an automobile that uses alcohol-mixed gasoline as fuel, Figure 2 is an overall configuration diagram showing the fuel supply system to the engine, and Figure 3 is an overall configuration diagram showing the fuel supply system to the engine. Figure 4 is a block diagram showing the circuit configuration of the embodiment, Figure 4 is a flowchart showing the filling process operation for alcohol-mixed gasoline, Figures 5 to 7 relate to the prior art, and Figure 5 shows the relationship between alcohol concentration and air-fuel ratio. Figure 6 is a diagram showing the specific configuration of a resistive alcohol sensor, and Figure 7 is a diagram showing changes in output voltage before and after refueling when fuels with different alcohol concentrations are refueled. be. 4...Fuel tank, 5...Fuel port cap, 7...
-Fuel piping, 9...Fuel injection valve, 14...Fuel pump, 15...Remaining amount sensor. Patent Applicant Japan Electronics Co., Ltd. Agent Patent Attorney Kazuhiko Hirose 7 Ko9fune P85 Procedural Manual (Method) 1. Indication of the Case 1999 Patent Application No. I Section 2. Name of the Invention Engine Fuel Supply device 3, relationship with the person making the amendment case

Claims (1)

[Claims] A fuel tank for storing alcohol mixed fuel, a refueling determining means for determining whether refueling work to the fuel tank is completed, and a fuel pipe disposed between the fuel tank and a fuel injection valve provided in the engine. a fuel pump that supplies the alcohol-mixed fuel in the fuel tank to the fuel injection valve via the fuel pipe; and driving the fuel pump for a certain period of time when the refueling determination means determines that the refueling operation has ended; A fuel supply device for an engine, comprising a new fuel filling means for filling the alcohol mixed fuel filled in the fuel tank from the fuel pipe to the fuel injection valve.