JPH02157447A - Fuel supply device of engine jointly using alcohol and gasoline - Google Patents

Abstract

PURPOSE:To make proper control of air fuel ratio with respect to the mix proportion by controlling the air amount injected from an air injecting device, which is furnished on a fuel passage to an injector to inject the fuel, on the basis of signal from an O2 sensor. CONSTITUTION:The mixture fuel of alcohol and gasoline is fed to an injector 9 by a fuel pump 8 and injected to a suction manifold 6. This injected mixture fuel mixes with the inhaled air in the manifold 6 and supplied to a combustion chamber 1a to be combusted there. The exhaust gas after combustion is exhausted to an exhaust manifold 12, and oxygen concentration in the exhaust gas is sensed by an O2 sensor 14. Because the fuel injection amount from injector 9 becomes too large when the gasoline content of the fuel is large, a signal is given to a solenoid valve 18 from a control unit 20 to open it, and new air is injected to the fuel passage to be injected together with the mixture fuel into the manifold 6 from the injector 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply device for an engine that uses alcohol and gasoline as fuel, and more particularly, to a fuel supply device for an engine that uses alcohol and gasoline as fuel, and more specifically, a fuel supply device for a motor vehicle that is suitable for using either alcohol, gasoline, or a mixture of both. (Below Plexible Fuel Vehicle,
The present invention relates to a fuel supply device for an engine (referred to as FFV).

[Conventional technology]

Various methods have been put into practical use to reduce pollution caused by automobile exhaust gas, including the use of alternative fuels.

That is, the use of alcohol fuel such as methanol in place of gasoline is being considered.

However, the above-mentioned alcohol fuel is not suitable for mass production, and there is a problem in that it takes a considerable period of time to secure the required amount on a par with current gasoline.

Therefore, today a complete transition to alcohol vehicles is not possible, and motor vehicles (FFVs) are being developed that are suitable for fueling either alcohol, gasoline or a mixture of both. In the above-mentioned FFV, in order to operate the engine in an optimal state, the air-fuel ratio, fuel injection amount, and ignition timing must be set appropriately for the total mixture ratio of alcohol and gasoline in the fuel.

Therefore, conventionally, fuel supply devices for FFV include
A fuel-injected engine uses gasoline as the main fuel and alcohol as the auxiliary fuel, and either the main fuel or the auxiliary fuel is selectively supplied into the cylinder via a valve device depending on the operating condition of the engine. Prior art is known to do so.

[Problem to be solved by the invention]

However, the calorific value per unit volume of the fuel gasoline and alcohol in the FFV described above is significantly different. In order to obtain the equivalent calorific value of gasoline with alcohol fuel, it is necessary to use approximately twice as much alcohol fuel as gasoline. Requires.

Therefore, in the above-mentioned prior art fuel supply system, if gasoline and alcohol are to be injected from the same injector, a large-capacity injector that injects 100% alcohol fuel must be used; When the amount increases, the amount of injection by the injector decreases, exceeding the control limit specific to the injector, resulting in excess fuel, resulting in an overrich air-fuel ratio and increased emissions. Moreover, there is a problem in that it is difficult to control the air-fuel ratio to the stoichiometric air-fuel ratio.

The present invention has been proposed with the above-mentioned problem in mind, and is an FFV engine that uses alcohol, gasoline, or a mixture of both as fuel, and includes an air injection device in the fuel passage to the injector that injects the fuel. The amount of air injected from the air injection device is controlled based on the output signal from the 02 (oxygen) sensor installed in the exhaust manifold, and the amount of fuel injection is controlled to eliminate alcohol and gasoline contained in the fuel. The object of the present invention is to provide a fuel supply system for an alcohol/gasoline engine that controls the air-fuel ratio to a proper state for the total mixture ratio.

[Means to solve the problem]

In order to achieve the above object, alcohol and
The fuel supply system for gasoline engines uses alcohol,
In an automobile engine that uses gasoline or a mixture of both as fuel, an air injection device is provided in a fuel passage to an injector that supplies fuel to the engine, and the air injection device is a pump that pressurizes air diverted from an air cleaner. , consists of a solenoid valve that controls the amount of injected air, and a control unit that duty-controls the opening and closing of the solenoid valve, and an output signal output from the control unit to the solenoid valve is detected by an 02 sensor installed in the exhaust manifold. This feature is characterized in that it is controlled based on the received signal.

[For production]

As described above, according to the present invention, the amount of air corresponding to the mixing ratio of alcohol and gasoline in the fuel is injected into the fuel injected from the injector of the FFv engine while being controlled by the solenoid valve. Even if the injector characteristics are set based on the fuel injection amount of 100% alcohol, the amount of air injected into the fuel passage from the air injection device increases as the proportion of gasoline contained in the fuel increases. The air-fuel ratio can be controlled to the stoichiometric air-fuel ratio by controlling the fuel injection amount.

By controlling the amount of air and fuel injected from the injector that injects air into the fuel in the fuel passage, it is possible to control the air-fuel ratio with high precision, and it is possible to control the air-fuel ratio with high accuracy. Effenjin for FFVs can be used without the need to distinguish between alcohol fuel and gasoline fuel when refueling.

[Example] Hereinafter, an example of the present invention will be specifically described based on the drawings.

Figure 1 shows the schematic configuration of Efengin for FFV.
Reference numeral 1 denotes the engine body, in which air taken in from the air cleaner 2 passes through an intake pipe 4, the amount of intake air is opened and closed by a throttle valve 5 according to the engine load, and is sent through an intake manifold 6 into the combustion chamber la. is supplied to

On the other hand, the fuel for the engine body 1 is alcohol.

Gasoline or a mixture of both is used, and is sent from the fuel tank 7 by the fuel pump 8 to the injector 9 exposed in the intake manifold 6 corresponding to each cylinder, and is injected into the intake manifold 6 as a mixture. Supplied. The fuel pressure to the injector 9 is regulated by a pressure regulator IO that opens and closes based on the negative pressure in the intake manifold B, and the relief fuel from the injector 9 returns to the fuel tank 7 via the fuel passage 11. Then, the exhaust gas from the combustion chamber 1a is transferred to the exhaust manifold 12.
It is purified by the catalytic converter 13 and discharged from a muffler (not shown).

The control unit 20 that controls this engine is composed of a microcomputer, etc., and takes in the signal detected by the 02 sensor 14 arranged in the exhaust manifold 12, and controls the amount of fuel injected into the injector 9, the amount of air injected into the injector 9, and the like. Executes various controls such as ignition timing control.

Further, as shown in FIG. 2, the air injection device 15 is configured to inject clean air into the fuel passage 9a of the injector 9 via an injection vibrator IB.

The air injection device 15 includes an air pump 17 that pressurizes clean air separated from the air cleaner 2 via an injection vibrator [6], a solenoid valve 18 that controls the amount of air to be injected, and a device that prevents backflow of fuel from the injector 9. It consists of a one-way valve 19. The solenoid valve 18 is opened and closed controlled by an output signal outputted by inputting a signal detected by the 02 sensor 14 installed in the exhaust manifold 12 to the control unit 20.

That is, when the air-fuel ratio rich signal continues for a predetermined time (for example, 1 to 25 ec) by the 02 sensor 14, the solenoid valve 18 is duty-controlled by the output signal from the control unit 20, and a predetermined amount of air is injected from the air injection device 15. It is meant to be injected.

Next, the operation of the fuel supply device configured as described above will be described.

First, since the FFV engine according to the present invention, alcohol gasoline, or a mixture of both fuels is used as appropriate, the characteristics of the injector 9 are set based on the fuel injection amount for 100% alcohol. When alcohol and gasoline are mixed in the fuel tank 7, the mixed fuel of alcohol and gasoline is sent to the injector 9 by the fuel pump 8 and injected into the intake manifold 6. The injected mixed fuel is mixed with the intake air of the intake manifold 6, supplied to the combustion chamber 1a, and combusted in the combustion chamber 1a. The exhaust gas after combustion is transferred to the exhaust manifold 12.
The oxygen concentration in the exhaust gas is detected by the 02 sensor 14.
detected by.

In this case, if the gasoline content in the fuel is high, the amount of fuel injected from the injector 9 will be excessive, so the 02 sensor 14 detects an overrich state.

Therefore, when the overrich state is continuously detected by the 02 sensor 14 for a predetermined period of time, the control unit 2
outputs a signal to the solenoid valve 18 to open the solenoid valve 18. When the solenoid valve I8 is opened, the air pump I7 injects fresh air from the air cleaner 2 through the injection pipe 16 into the fuel passage 9a.
The mixed fuel is injected from the injector 9 into the intake manifold 6 along with the mixed fuel.

Therefore, the amount of intake air supplied to the combustion chamber 1a is determined by the amount of air injected from the air injection device 15 into the throttle valve 5.
Since the amount of intake air is added to the amount of intake air taken in through the air, the amount of intake air increases, so a proper air-fuel ratio can be obtained.

Moreover, the opening and closing of the solenoid valve I8 is duty controlled based on a signal detected by the 02 sensor 14 corresponding to the content of gasoline.

Note that when the engine accelerates, an acceleration signal (not shown) is input to the control unit 20 and output, thereby controlling the solenoid valve 1.
8 can be closed to cut off the amount of injected air and improve acceleration.

〔Effect of the invention〕

As described above, according to the present invention, in an FFV engine, an air injection device is provided in the fuel passage to the injector that injects fuel, and the amount of air injected from the air injection device is transferred into the exhaust manifold. It is configured to be controlled based on the signal detected by the installed 02 sensor, and by controlling the amount of air injected by the air injection device and the amount of fuel injection from the injector,
The air-fuel ratio relative to the mixture ratio of alcohol and gasoline contained in the fuel used can be controlled to an appropriate state.

Furthermore, by detecting the oxygen concentration in the exhaust gas, it is possible to control the air-fuel ratio in accordance with the gasoline ratio of the mixed fuel, eliminating the need for an alcohol concentration sensor, simplifying the structure and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing the main part of FIG. 1. 1...Engine body, 2...Air cleaner, 6...
・Intake manifold, 7...Fuel tank, 12...
Exhaust manifold, 14...02 sensor, 15...
Air injection device, 1B... Injection vibrator, 17... Pump, 18... Solenoid valve, 19... One-way valve, 20...
·Controller unit.

Claims (1)

[Claims] In an automobile engine that uses alcohol, gasoline, or a mixture of both as fuel, an air injection device is provided in a fuel passage to an injector that supplies fuel to the engine, and the air injection device is connected to an air cleaner. It consists of a pump that pressurizes the diverted air, a solenoid valve that controls the amount of air to be injected, and a control unit that controls the opening and closing of the solenoid valve, and outputs an output signal from the control unit to the solenoid valve to A fuel supply device for an alcohol/gasoline combined engine, characterized in that the device is controlled based on a signal detected by an O_2 sensor installed in a manifold.