JPH0354332A - Control device for fuel injection timing of internal combustion engine - Google Patents

Abstract

PURPOSE:To contrive the improvement of exhaust gas and fuel consumption by controlling an injector so as to advance fuel injection timing in accordance with an increase of alcohol concentration, in the case of an internal combustion engine in which alcohol and gasoline can be used singly or mixedly as fuel. CONSTITUTION:When a signal is input into an electronic control unit 6 from an alcohol concentration sensor 9, cooling water temperature sensor 13, etc., fuel injection timing of an injector 11 is calculated and determined. A fuel injection amount is increased following a decrease of theoretical air-fuel ratio with alcohol concentration increased, when a time for vaporizing fuel is increased, the fuel injection timing of the injector 11 is advanced. Accordingly, a time from opening an intake valve 5 or the like to suction into a combustion chamber 3 is taken longer as compared with high gasoline concentration, and fuel is sufficiently vaporized during the time before suction into the combustion chamber 3. As a result, improvement of exhaust gas and fuel consumption can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection timing control device for an internal combustion engine that can use alcohol and gasoline as fuel, either alone or in a mixture of both. (Prior Art) Methanol alcohol is used as a fuel in internal combustion engines such as automobile engines.Hereafter, it is simply referred to as "alcohol."
) and gasoline can be used alone or in combination, and some countries are actively promoting automobiles equipped with this type of internal combustion engine. In this internal combustion engine, the alcohol concentration in gasoline is 0%.
That is, the stoichiometric air-fuel ratio when using only gasoline is approximately 14.
7, and conversely, the alcohol concentration is 1. O O%, that is, the buried air-fuel ratio when using only alcohol is approximately 6.4.
Therefore, when using 100% alcohol, 2.3 times more fuel must be injected than when using 100% gasoline. Therefore, in a conventional internal combustion engine of this type, gasoline
As shown in Figure 5, fuel injection starts from the injector at the same time when the crank angle sensor signal turns on. However, in the case of 100% alcohol, which requires a large amount of fuel to be injected, the injection time is approximately 23 times longer. Additionally, it takes approximately 2.3 times longer for the injected fuel to vaporize when using 100% alcohol than when using 100% gasoline, as the amount of fuel used is larger. ．． Furthermore, the heat of vaporization required to vaporize each fuel is 80keaQ/kg for gasoline, but 263kcaQ/y for alcohol.
As you can see, it takes about three times as much, and depending on the cooling water temperature, you may have to warm up the alcohol by this amount or take more time. (Problem to be solved by the invention) Therefore, in the conventional internal combustion engine, which is operated without changing the injection timing of the injector depending on whether gasoline is used as fuel or alcohol is used as fuel, the time required for vaporization is cannot be removed sufficiently when alcohol fuel is used. As a result, the amount of unburned substances increases, and a large amount of substances such as carbon C, monoxide monoxide CO, dicombusted methanol, and formaldehyde with a pungent odor are emitted in the exhaust gas, causing pollution. There are problems such as increased fuel consumption and poor fuel efficiency. Also, the above points apply to whether 100% alcohol or 100% gasoline is used on the other hand, but depending on the area, there may be only gas stations or only alcohol stations. ．． In such a case, for example, if you filled up with fuel at a gas station before, tried to put it back in after driving a certain number of kilometers, but couldn't find a place to put it in, so you put alcohol in it. The mixing ratio of alcohol and gasoline differs each time depending on the amount of alcohol and the amount of alcohol newly added. Therefore, in order to improve exhaust gas and fuel efficiency, it is necessary to be able to cope with conditions that vary depending on the mixing ratio of alcohol and gasoline and the temperature of cold fl and water, which changes each time.The present invention solves this problem. The purpose of this invention is to provide a fuel injection timing control device for an internal combustion engine that has a structure that can improve exhaust gas emissions and fuel efficiency. (Means for Solving Problem yA) In order to achieve the above object, a fuel injection timing control device for an internal combustion engine according to the present invention includes: a sensor that detects the alcohol concentration in fuel; an injector that injects the fuel; an electronic control unit that controls fuel injection timing of the injector according to a signal from the sensor, and controls the electronic control unit to advance the fuel injection timing of the injector as the alcohol concentration in the fuel increases. It is configured to do this. (Function) According to this configuration, when the alcohol concentration increases and the stoichiometric air-fuel ratio decreases, the amount of fuel injected increases and the time required to vaporize the fuel increases. Because the timing is brought forward, there is more time for the intake valve to open and intake into the combustion chamber.
Therefore, even if the mixing ratio of alcohol and gasoline is different, sufficient vaporization of the injected fuel can be achieved, eliminating unburned components. (Implementation PA) Hereinafter, embodiments of the present invention will be described in detail using the drawings. FIG. 1 is a schematic elliptical diagram of the main parts of an engine to which a fuel injection timing control device according to an embodiment of the present invention is applied. In the figure, this engine is an example of an engine that can use alcohol and gasoline as fuel, either alone or in a mixture of both. And piston 2
, a combustion chamber 3, an exhaust valve 4, an intake valve 5, etc., an engine body 1, a fail tank 7 that can hold alcohol and gasoline as fuel, and a fuel pump to pump out the fuel in the fail tank 7. A bomb 8, an alcohol concentration sensor 9 that detects the alcohol concentration in the fuel pumped out by the fuel bomb 8, and an injector 11 that injects the fuel pumped out by the fuel bomb 8 into an intake pipe 19. The air cleaner 12, throttle valve 10, surge tank 18, electronic control unit 6, etc. are controlled. In addition, the electronic control unit 6
In addition to the alcohol concentration sensor 9, there are also a cooling water temperature sensor 13, a crank angle sensor 14, and an air flow sensor 1.
5. An intake air temperature sensor 16, an intake pressure sensor 17, and a fail sensor 20 are connected to each other, and the information detected by these sensors is inputted to each of them. Based on this information, etc., the electronic control unit 6 determines the increase value of the fuel injection amount of the injector 11, and can control it every time the cranking time elapses. This electronic control unit 6 is mainly composed of a microcomputer, and is preset to perform processing according to the flowchart shown in FIG. In addition, in this embodiment, the injection timing of the injector 11 at the time of setting is based on the case where 100% gasoline fuel is used, and the injection timing and the valve opening time of the injector 11 are changed according to the alcohol concentration in the fuel and the cooling water temperature. It is now possible to do this. Figure 3 shows the injection timing and valve opening time of the injector 11 when using 100% gasoline fuel and when using 100% alcohol fuel. The injection timing is advanced compared to when using gasoline, which opens the intake valve 5 and the combustion chamber 3.
This allows more time for it to be inhaled into the body. This fuel injection timing is set based on the crank angle determined by the signal from the crank angle sensor 22, but in this embodiment, compared to the case where 100% gasoline fuel is used, 100% alcohol fuel is used. When used, when the cooling water temperature is 80℃, gasoline 100
Fuel injection starts approximately 70 degrees earlier in rotation angle than in the case where 50% of fuel is used, and the shift angle is set in relation to the alcohol concentration, for example, as shown in Fig. 4. Additionally, this relationship changes depending on the cooling water temperature; the value shown by solid line A in Figure 4 is when the cooling water temperature is 80°C, and the value shown by dotted line B in the figure is when the cooling water temperature is 0°C. be. As the cooling water temperature decreases and the alcohol concentration increases, it takes longer to vaporize, so the injection timing is advanced in proportion to the increase in time between injection and the opening of the intake valve. Conversely, as the cooling water temperature increases and the alcohol concentration decreases, the time from injection to the opening of the intake valve is reduced, making it more similar to the case with gasoline fuel. The operation of the internal combustion engine configured as described above will now be explained using the flowchart shown in FIG. First, when a key (not shown) is inserted and the power is turned on, the flow shown in Figure 2 starts. Then, signals are input from the alcohol concentration sensor 9, cooling water temperature sensor 13, etc. into the electronic control unit 6 (see step STI).Next, based on these signals, the valve opening time of the injector 11 is calculated in step ST2. At the same time, calculation is performed in step ST3 to calculate and determine the fuel injection timing of the injector 11. Based on this determination, the fuel injection timing and valve opening time of the injector 11 are determined in step ST4. This state is sequentially repeated.Furthermore, the flow ends when the key is turned off and the engine stops.Therefore, in the internal combustion engine according to this embodiment, the alcohol concentration increases and the stoichiometric air-fuel ratio decreases. As the amount of fuel to be injected increases and the time required to vaporize the fuel increases, the fuel injection timing of the injector 11 is advanced in response to this, so the intake valve 5 etc. open and the fuel flows into the combustion chamber 3. It takes more time for the fuel to be inhaled than when the gasoline concentration is high.As a result, even if the alcohol concentration increases and the stoichiometric air-fuel ratio decreases, the fuel is not absorbed until it is inhaled into the combustion chamber 3. Since the fuel is inhaled into the combustion chamber 3 in a sufficiently vaporized state, there are no unburned substances.As a result, it is possible to improve exhaust gas and fuel efficiency.Furthermore, the fuel vaporizes at low temperatures. Furthermore, in the above embodiment, when setting the fuel injection timing of the injector 11, the alcohol concentration and the cooling water temperature are used as determining factors, but if the alcohol concentration is taken into consideration, the cooling water temperature can be changed. (Effects of the Invention) As explained above, according to the fuel injection timing control device for an internal combustion engine according to the present invention, the alcohol concentration increases and the stoichiometric air-fuel ratio decreases. As a result, the amount of fuel injected increases and the time required to vaporize the fuel increases, so the fuel injection timing of the injector is advanced, so the time it takes for the intake valve to open and the gasoline to be sucked into the combustion chamber is reduced. Therefore, even if the mixing ratio of alcohol and gasoline is different, sufficient vaporization of the injected fuel is obtained and there is no unburned fuel.As a result,
Improved exhaust gas and fuel efficiency can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the main parts of an internal combustion engine to which an embodiment of the present invention is applied, and Fig. 2 is a flowchart showing an example of a program in the electronic control unit that executes the fuel injection timing control device of the internal combustion engine. , Figure 3 is an operation explanatory diagram showing the relationship between the injector injection timing and crank angle for the same internal combustion engine for each fuel, Figure 4 is a diagram showing the relationship between the alcohol concentration and the injector injection timing, and Figure 5 is a diagram showing the relationship between the injector injection timing and the crank angle. FIG. 2 is an operational explanatory diagram showing the relationship between injector injection timing and crank angle for each fuel in a conventional internal combustion engine. 9... Alcohol concentration sensor, 6... Electronic control unit, 11... Injector. To figure 2 figure 3 figure 4 figure =71Lko<()/=ノ

Claims (1)

[Claims] A fuel injection timing control device for an internal combustion engine that can use alcohol and gasoline as fuel, either alone or in combination, comprising: a sensor that detects the alcohol concentration in the fuel; an injector that injects the fuel; an electronic control unit that controls the fuel injection timing of the injector according to a signal, and the electronic control unit controls the fuel injection timing of the injector to advance as the alcohol concentration in the fuel increases. Features: Fuel injection timing control device for internal combustion engines.