JPS6364620B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine control device used in automobiles and the like, and particularly to an engine control device suitable for using fuel mixed with alcohol or the like.

In a conventional engine control device that uses gasoline as fuel, when alcohol-containing fuel is used, the air-fuel ratio, ignition timing, and exhaust gas recirculation amount deviate from optimal values, resulting in a decline in engine performance. This is reported in the following documents.

Society of Automotive Engineers of Japan, Academic Lecture Preprint Collection 811,
No. 18 (May 1981) Generally, as the alcohol content X increases, the stoichiometric air-fuel ratio decreases, and in conventional devices for gasoline, the mixture becomes leaner. For example, when using gasoline mixed with 20% methanol, the stoichiometric air-fuel ratio A/F is
Since the fuel consumption decreases from 15 to 13, the air-fuel mixture will be diluted by about 15% if the conventional device is used. When this happens, the operating performance of the engine deteriorates, and the exhaust gas composition changes, causing problems such as deterioration of the purifying action of the catalyst.

An object of the present invention is to provide an engine control device that can perform good control by obtaining the optimum air-fuel ratio according to the mixing ratio of alcohol, etc. A program is provided to modify the signal regarding the amount of fuel according to the information on this information and changes in the engine temperature, and the air-fuel ratio of the air-fuel mixture to be supplied to the engine is determined according to the alcohol content in the fuel.

FIG. 1 is a system diagram of an engine control device that is an embodiment of the present invention. A throttle valve 3 is installed in the intake pipe 2 connected to the engine 1, the upstream side of the throttle valve 3 is connected to an air cylinder equipped with an air flow meter 4, and the downstream side of the throttle valve 3 is installed with a fuel injection valve 5. has been done. Further, a spark plug 6 is installed in each cylinder of the engine 1, and an exhaust gas sensor 7 is installed in the exhaust pipe 8 of the engine 1. Furthermore, the exhaust pipe 8 and the intake pipe 2 are referred to as an exhaust gas recirculation device (hereinafter referred to as
(denoted as EGR) 34.
34 is controlled by a solenoid valve 33 connected to the output device 17.

The fuel injection valve 5 communicates with a pressure regulator 12, a filter 13, and a pump 14 via a metering valve 9 and an alcohol mixing rate detector 10. Further, both the pump 14 and the pressure regulator 12 communicate with a fuel tank 15. That is, pump 14
sucks the alcohol-containing fuel in the fuel tank 15 and pressure-feeds it to the fuel injection valve 5 and pressure regulator 12 via the filter 13, and the remaining fuel that is not injected by the fuel injection valve 5 is returned to the fuel tank 1 via the return passage.
5, and a predetermined fuel pressure is always applied to the fuel injection valve 5.

The metering valve 9 is intermittently opened by a drive circuit 11 operated by an output signal from an output device 17, and injects an amount of fuel into the intake cylinder 2 appropriate for the operating condition. Further, a fuel amount meter 16 is attached to the fuel tank 15, and its output signal is sent to an input device 18. Note that this input device 18 includes the fuel amount meter 1.
6. The output signals of the air flow meter 4, the mixture ratio detector 10 that detects the alcohol mixture ratio, and the exhaust gas sensor 7 are input to the microprocessor 20.
I am sending it to

On the other hand, the output device 17 outputs the output to the drive circuit 11 and also outputs the output to the switch 31 connected to the power source 32.
The signal is outputted to the coil 30 via the power source and controls the power distributor 29. As a result, the ignition timing, that is, the advance angle, is determined to suit the operating conditions and the alcohol content, and the spark plug 6 is ignited. Further, this output device 17 outputs a signal to the electromagnetic valve 33.

The output device 17 and input device 18 are connected to a microprocessor 20, which has registers 21, 28, a storage device 22,
23, 24, 25, 26, and 27, and serves to temporarily store data processed by the microprocessor 20 and data from the output device 17 and input device 18. Note that the setting device 19 is a device for the operator to input data.

In the engine control device configured in this way, the air flow meter 4 outputs an electrical signal corresponding to the amount of intake air, and there are various types such as vane type, Kalmar type, hot wire type, and swirl type. There is no problem. That is, from these, the analog voltage Q, frequency f, period, duty ratio, etc. which are proportional to the amount of intake air are determined.

Now, let Y be the information corresponding to these air amounts, and let Z be the information regarding the corresponding fuel amount.
Since the fuel amount is controlled according to the change in the intake air amount, Z=φ(Y, A/F, ε)...(1) However, A/F is the set value of the air-fuel ratio, and ε is the intake air amount. This is a measurement error.

A/F is a function of the operating state of the engine, for example, the temperature θ of the engine 1, the rotation speed N, and the load y,
The A/F is stored in the storage device 27 in advance. Note that there is no need to memorize the absolute value of A/F.
It is sufficient to store the ratio k ₀ with respect to the reference value. The intake air amount Y is input to the microprocessor 20 via the input device 18. This microprocessor 2
0 reads k ₀ from the storage device 27, obtains information Z regarding the fuel amount based on the information Y, assumes ε=0, and outputs the information Z to the output device 17.

The output device 17 operates the drive circuit 11 to supply fuel according to Y from the metering valve 9 to the engine 1. The pump 14, filter 13, and fuel pressure regulator 12 can have the same configuration as a conventional control device. When the alcohol mixing rate X of the fuel supplied from the pump 14 changes, the contents of the register 28 are changed.

Now, assuming that the contents of the register 28 that change in response to X are _k1 , the microprocessor 20 calculates the fuel information Z by calculating the following formula. In this way, Z changes in accordance with the change in X, and the fuel amount is maintained appropriately. k ₁ for gasoline
= 1.0, in the case of 20% methanol, K ₁ =
It will be about 1.15. This rewriting of k ₁ is performed in the following manner.

(a) Manually set k ₁ on the setting device 19 and input device 1
8. Input signals to storage device 23 and register 28 via microprocessor 20; The setting device 19 may be a simple changeover switch, a push button switch, or a magnetic card. In this case, as can be seen from FIG. 1, the fuel present in the pipe between the fuel tank 15 and the metering valve 9 is
Since the new fuel is not replaced immediately, the value in the register 28 is replaced with the new value after a certain period of time has elapsed. This replacement is controlled by a microprocessor 20 timer. Furthermore, if the previous fuel remains in the fuel tank 15, the alcohol mixing rate is the same as when it is mixed with the previous fuel.

Now, assuming that the amount of residual fuel is F ₁ , the alcohol mixing rate is X ₁ , the amount of newly injected fuel is F ₂ , and the alcohol mixing rate is X ₂ , the actual mixing rate X is expressed by the following equation.

_{X = X 1 F 1 + _} The data is input to the processor 20.

(b) The mixture rate detector 10 utilizes changes in dielectric constant, etc., and is installed upstream of the fuel injection valve 5. With this, X is detected, and the fuel correction coefficient is rewritten using the function of X and _k1 . In this case, the signal from the mixing rate detector 10 is input to the microprocessor 20 via the input device 18, and _k1 corresponding to this signal value is determined and input to the register 28. The relationship between X and _k1 is stored in advance in the storage device 23. For example, the one shown in FIG.

(c) As the exhaust gas sensor 7, an oxygen sensor or the like made of a zirconia solid electrolyte material is used. This detects the oxygen concentration in the exhaust gas and controls the stoichiometric air-fuel ratio A/F of the mixture supplied to the engine 1 to be 14.7 (when using gasoline). (2)
In the equation, if k=1 in the operating range of k ₀ =1, if the alcohol mixing rate X changes, the fuel information Z will deviate from the appropriate value. If k ₂ is a correction coefficient, the following equation holds true.

Z=K ₆・k ₁・k ₂・Y... (3) When k ₂ = 1, it deviates from the proper value, but k ₂ is corrected based on the signal from exhaust gas sensor 7 so that it becomes the stoichiometric air-fuel ratio. Feedback control of Z is performed. For example, in the case of methanol contamination rate of 20%, the final
k ₂ = about 1.15. This value of k ₂ is stored in storage device 2.
2.

The value of _k2 during feedback control is in register 2.
1 is temporarily stored. Feedback control is stopped in the operating range where k ₀ ≠1. Now, when switching from fuel containing 20% methanol to gasoline, the mixture is in a state where k ₂ = 1.15, so the mixture temporarily becomes rich, but feedback control quickly returns the state to k ₂ = 1.0, that is, Return to proper air-fuel ratio. This feedback control operates only during steady state operation in the operating range of k ₀ =1.

In this method, k ₂ contains the measurement error ε of the intake air amount.
However, since the influence of ε differs depending on the operating conditions, the value of k ₂ also differs depending on the operating conditions, but this will be discussed later in Section 9.
This will be explained in the figure. Therefore, the storage device 22 storing k ₂ has multiple addresses.

(d) If a sensor that outputs a signal proportional to the excess air ratio λ is used as the exhaust gas sensor 7, compare the detected value of 1/λ with the value of k ₀ and calculate 1/λ. Feedback control is performed so that the value of k0 becomes the value of _k0 . The correction value k ₂ during this feedback control is stored in the storage device 22. In this case, the engine 1 does not need to be operated at the stoichiometric air-fuel ratio as in the case (e) below.

In this way, the memory device 27 sets the excess air ratio λ according to the operating conditions, and the alcohol mixing ratio
Proper fuel can be supplied to the engine 1 by providing the storage device 23 or the storage device 22 that stores the coefficient k ₁ that corrects the relationship between the amount of fuel and the amount of air according to the amount of fuel.

When the engine 1 is at a low temperature, it is necessary to set the excess air ratio λ smaller for the former than for the 20% methanol fuel and the gasoline only fuel, even under the same operating conditions, to ensure stable operation of the engine 1. For this reason, the set values in the storage device 27 are stored as a function of operating conditions, for example, the rotational speed n of the engine 1, the engine temperature θ, the load y, and information on X.

FIG. 2 is a diagram showing the relationship between the alcohol mixing ratio X and the A/F. As X increases, the A/F decreases and the amount of air decreases. With the method using the exhaust gas sensor 7 as explained in (c) and (d) above, it is not possible to distinguish between ethanol and metal. However, as can be seen from this figure, with the same A/F, the mixing rate of ethanol is large, so even if the set value of λ at low temperature is determined using the values of k ₁ and k ₂ found from the correction value of feedback control. It's not a big problem.

FIG. 3 is a diagram showing the relationship between the alcohol mixing rate X and the calorific value, and as the alcohol mixing rate increases, the calorific value decreases. However, as shown in FIG. 4, when the same amount of air as in the case of gasoline is mixed, as X increases, the calorific value increases slightly. Therefore,
If the A/F is applied to X as shown in FIG. 2, the engine output will increase slightly as X increases.

FIG. 5 is a diagram showing the relationship between the alcohol mixing ratio X and the ignition timing, where the ignition timing is shown in terms of the crank angle of the engine 1, and the excess air ratio λ is shown as a parameter. Even if X changes, the ignition timing hardly changes, but as λ increases, it becomes necessary to advance the ignition timing. Storage device 26
The set ignition timing for the operating conditions is stored in the memory, and the switch 31 is operated based on this information to open and close the circuit between the power source 32 and the coil 30 to generate high voltage. This high voltage ignites the spark plug 6 via the power distributor 29.

The set ignition timing is determined by engine 1 rotation speed and intake pipe 2.
Since an appropriate value has been given in advance for the pressure, the set ignition timing for the corresponding operating condition is read out from the storage device 26 using an address related to the rotational speed and intake pipe pressure. In the embodiment shown in FIG. 1, the pressure inside the intake pipe 2 is not directly detected, so the corresponding ignition timing is determined from the intake air amount information Y, that is, the signal from the air flow meter 4. The ignition timing may also be controlled by a conventional mechanical ignition timing controller, such as a governor or vacuum timing controller.

Furthermore, depending on the type of engine 1, it is necessary to change the ignition timing depending on the alcohol mixing ratio X, and even when λ is not corrected, the ignition timing needs to be changed. In this case, the ignition timing correction value for X is stored in the storage device 25.

Some gasoline engines are equipped with BGR34, but the operating point of EGR34 is usually determined by the pressure in the intake pipe 2 and the opening degree of the throttle valve 3. If the excess air ratio λ and ignition timing are controlled correctly using the above method, as can be seen from the change in heat value shown in Figure 4, the change in heat value for the same amount of air, that is, the change in generated torque, will be small and the EGR will be reduced.
The operating point of No. 34 also does not change much.

Figure 6 shows the alcohol mixing rate X and the amount of alcohol in the exhaust gas.
This is a diagram showing the relationship with the amount of NOx, where the amount of NOx is shown in ppm. NOx tends to decrease as X increases, but NOx can be reduced even if the set value at which the EGR 34 operates is lowered.

The EGR 34 has a diaphragm valve that operates under suction load. The setting value for X is stored in advance in the storage device 24, and the solenoid valve 33 is
By operating the diaphragm valve to adjust the negative pressure applied to the diaphragm valve, the amount of exhaust gas recirculation can be controlled according to X.

FIG. 7 is a diagram showing the relationship between the engine temperature θ and the fuel correction coefficient k ₀ , which shows different values depending on the value of the alcohol mixing ratio X. The solid line is for X=0, the dashed line is for X=0, and the broken line is for X=0.1.
The case is shown below.

FIG. 8 is a flowchart showing an example of the control operation of the engine control device shown in FIG. In the case of gasoline fuel, the engine speed N, engine temperature θ, and air amount information Y are measured in block 101, and the set value _k0 of the air-fuel ratio, which is the corresponding operating condition, is read out. In this case, since X=0 or is very small, the fuel amount is calculated directly in block 104 and the process returns to block 101.

If the alcohol contamination rate X cannot be ignored, make the above correction and
Measure X at Further, in block 105, k ₁ corresponding to X is determined, and then the process moves to block 104. When performing feedback control using the exhaust gas sensor 7, the measured value 1/λ and _k0 are compared in block 106, and if 1/ _λ0 - _k0 is positive (1/λ- _K0 >0)
If so, K ₂ is decreased in block 107, and if negative, K ₂ is increased in block 108, and the fuel amount Z is increased or decreased in block 109.

Control of ignition timing and exhaust gas recirculation amount is also performed using a similar flowchart. Fuel correction during acceleration is also performed by controlling the correction amount based on the acceleration and the value of X. Further, although the embodiment shown in FIG. 1 deals with a fuel injection device, the fuel amount is corrected using a similar control method in the case of a carburetor as well.

It is known to control the amount of fuel in a carburetor by adjusting the jet diameter and air bleed diameter. This is equivalent to adjusting the fuel amount by changing K ₀ in FIG. 8, and in the present invention, the jet diameter and air bleed diameter are adjusted according to the change in X. In this case, K ₀ is not uniformly corrected with respect to the temperature θ of the engine 1, and it is necessary to change it with respect to X as follows.

This can be achieved by controlling the current of the heater that controls the opening of the choke valve in accordance with X. Alternatively, the amount of cooling water used to heat the wax temperature sensitive body may be adjusted. By making the storage device replaceable, it is possible to accommodate a wide range of fuel changes.

When metering fuel intermittently with respect to the metering valve 9, if controlled with a valve opening time of 1 to 5 ms, the valve opening time increases by 15% in the case of 20% methanol. At high speeds and high loads, the front and back of the valve opening and closing operations tend to get stuck. For this reason, it is necessary to determine the opening area of the metering valve 9 with some allowance. However, if there is too much margin, the valve opening time during idling operation becomes too short. Therefore, if X changes significantly, it is necessary to replace the metering valve 9 itself.

FIG. 9 is a program for rewriting information in the second storage means using a magnetic card in which information regarding fuel properties is stored. When a magnetic card is inserted, the microprocessor 20 reads the information on the magnetic card by an interrupt operation. After counting and incrementing the number of programs to be executed thereafter, that is, after a certain operating time has elapsed, the second storage device is rewritten.

FIG. 10 is a numerical table of the fuel correction coefficient k in the third storage means that is rewritten by the exhaust gas sensor. It is addressed by the rotational speed n npm of the engine 1 and the load factor y, and the value at an intermediate speed rotation and an intermediate load factor is the maximum value. That is, when the feedback control is limited to the range of 2000<n<4000 and 0.2<y<0.8, such a fuel correction coefficient k is stored when the mixing ratio X of methanol is 20%. n,y
If it exceeds the above range, it has not been corrected. Since k ₂ =1.00 remains in this region, the amount of fuel decreases. Therefore, either transfer the average value of k ₂ within the above range to k ₁ and operate with k ₂ = 1.00 using equation (3), or extrapolate the value of k ₂ within the above range and calculate the value outside the above range. It is necessary to find the value of k ₂ .

Figure 11 shows alcohol contamination rate X and fuel correction coefficient
This is a diagram showing the relationship with k _1. The relationship of this straight line is stored in advance in the second storage means and k ₁ is obtained. By correcting this k ₁ , the deviation in air-fuel ratio due to the properties of the fuel can be corrected. However, with the air-fuel ratio set for gasoline, it is difficult to operate the engine smoothly at low temperatures. Therefore, the following modification method is used.

FIG. 12 is a numerical table showing correction values determined by the alcohol mixing rate X and the engine temperature θ.
The values shown in FIG. 12, which are determined as functions of X and θ, which are information regarding the properties of the fuel, are stored in the fourth storage means. This modified value is stored in the memory device that addressed X and θ. Alternatively, it may be derived from a functional relationship such as the following polynomial.

k ₀ = φ (X, θ, n, y) ...(4) The temperature of engine 1 is the cooling water temperature, intake pipe 2
temperature, oil temperature, cylinder temperature, etc.

Although the air flow meter 4 is used as the air amount detection means in this case, a method of determining the air amount from the intake pressure and the rotational speed of the engine 1 may also be used.

FIG. 13 is a diagram showing the relationship between engine temperature θ and engine speed n. It is common practice to temporarily cut off fuel when decelerating a car. For example, if the fuel is cut off when the rotational speed of the engine 1 is _n1 , the rotational speed will decrease as shown by the solid line B, and when the target n is reached, a suitable amount of fuel will be supplied. This is the case when gasoline is used, but as _the alcohol mixing ratio
It is added to the 0 program. That is, in the case of alcohol-containing fuel, the engine temperature will not rise unless the engine speed is increased. Note that the case of _n2 , which has a high rotational speed, also exhibits the same characteristics as the case of _n1 .

FIG. 14 is a flowchart showing an embodiment of a program for modifying a signal related to the amount of fuel injected by the fuel injection device. The basic injection amount Δt ₀ is determined by the intake air amount and the engine speed. This Δt ₀ is corrected by k ₁ to obtain Et _s , and the fuel injection valve is operated based on this. k ₀ is a basic correction value determined by X, and in the case of gasoline, k ₀ =1. k ₁ is a coefficient that corrects the fuel evaporation delay when the engine cooling water temperature θ _w is low, and it also changes depending on X, and when θ _w > 60°C, k ₁ = 1
becomes.

When the ignition key of engine 1 is in the starting position, or when the engine coolant temperature θ _w is θ _w0
(X) Increase cranking in the following cases. θ _w0 (X) for gasoline alone is 25°C, and as X increases, θ _w0 is increased to facilitate cranking. When θ _w is less than θ _w0 , the cranking rotation speed is low, so Δt _w is set by θ _w and X, and k ₂ ,
Correct by k ₃ to determine Δt _s .

t is the duration of cranking, and k ₃ becomes zero at about t=12 seconds. This k ₃ is set to increase as X increases. k ₄ is a constant correction coefficient during cranking. Moreover, t ₀ is the cranking increase time.

The engine control device of this embodiment can change the operating range of cranking increase, which determines the fuel amount regardless of the air amount, according to information such as information on the properties of the fuel, so even when alcohol is mixed, the engine control device can quickly The engine can be started. Separate correction coefficients are prepared for the cooling water temperature θ _w and the mixing rate X for t ₂ hours after startup. Further, this time _t2 differs depending on the type of idle switch and the mixing rate X.

Also, when starting or accelerating at θ _w < 80℃,
Correct Δt by _k6 . This correction time t ₃ is a function of θ _w and X, and when X is X ₁ and X ₂ , k ₆ and t ₃ are given by a curve as shown in FIG. 15.

Fig. 15 is a diagram showing the relationship between the engine cooling water temperature θ _w and k ₆ , t ₃ , Fig. 15 a shows the relationship with the correction coefficient k ₆ , and Fig. 15 b shows the relationship with the idling time t ₃ . It is a relationship. The second storage means for storing information regarding the properties of the fuel, such as the alcohol content ratio X, is a rewritable storage device. Information stored in a storage device such as a flip-flop disappears as soon as the power is turned off. In the method using the manual setting device 19 and the alcohol contamination rate detector 10, no particular problem occurs even with such a storage device. However, in the case of correction using feedback control, it is desirable to use the corrected value upon restart, and it is possible to retain the information without cutting off the power to the storage device.

The pump 14 is driven by an electric motor or an electromagnet. In the configuration shown in FIG. 1, the pump 14 is driven to rotate at a constant speed. As shown in FIG. 11, as X increases, the fuel correction coefficient _k1 increases, so it is necessary to increase the amount of liquid fed by the pump 14.

FIG. 16 is a circuit diagram of the pump motor. The motor 35 that drives the pump 14 is connected to the current control circuit 3
The motor 35 is connected to a power source 32 via a power source 32, and the number of revolutions of the motor 35 can be adjusted according to the alcohol mixing rate X. The current control circuit 36 is connected to the microprocessor 20 via the input device 18 and the output device 17, and the rotation speed when using only gasoline is
If it is 1000rpm, only alcohol (X=
100%), the rotation speed automatically increases to about 2000 rpm. Current control circuit 36
processes the output of the mixing ratio detector 10 and outputs the output device 1.
Since it is activated by the signal sent from 7, the alcohol mixing rate X is automatically detected and the current control circuit 36 is automatically operated in an appropriate state. Therefore, the power consumption of the motor 35 can be saved.

The engine control device of this embodiment includes a first storage means for storing a set air-fuel ratio as a function of engine rotational speed and load, an air amount detection means for outputting an electrical signal, and an output of the air amount detection means. A microprocessor that calculates a signal related to the fuel amount from the signal and the air-fuel ratio set in the first storage device, a second storage device that stores information related to fuel properties such as alcohol content, and the second storage device. A program that modifies the signal regarding the fuel quantity with the information of the second
and a microprocessor input device for rewriting the information in the second storage means, and has the effect that a program for modifying the information in the second storage means and the signal regarding the fuel amount according to the temperature change of the engine can be obtained. There is.

The engine control device of the present invention has the advantage that even if alcohol or the like is mixed into gasoline, the mixing rate can be automatically measured and calculated by the electronic control device to ensure optimal operation. is obtained.

[Brief explanation of drawings]

Fig. 1 is a system diagram of an engine control device that is an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between alcohol mixing ratio X and air-fuel ratio A/F, and Fig. 3 is a diagram showing the relationship between X and calorific value. Figure 4 is a diagram showing the relationship between X and calorific value when the amount of air is the same as in the case of gasoline. Figure 6 is a diagram showing the relationship between X and the amount of NOx in exhaust gas, Figure 7 is a diagram showing the relationship between engine temperature θ and fuel correction coefficient k ₀ , and Figure 8 is the engine control shown in Figure 1. A flowchart showing an example of the control operation of the device,
FIG. 9 shows an information rewriting program using a magnetic card in which information on fuel properties is stored, and FIG. 10 shows an information rewriting program using the exhaust gas sensor shown in FIG. 1.
An example of a numerical table, Fig. 11 is a diagram showing the relationship between X and the fuel amount correction value _k1 , Fig. 12 is a numerical table showing the correction value determined by A diagram showing the relationship with the engine rotation speed n, Fig. 14 is a flowchart showing an example of a program for correcting the signal related to the amount of fuel injected by the fuel injection device, and Fig. 15 shows the relationship between the engine cooling water temperature θ _w and the fuel correction coefficient k ₆ FIG. ₁₆ is a circuit diagram of the pump motor. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake pipe, 3... Throttle valve, 4... Air flow meter, 5... Fuel injection valve, 6... Spark plug, 7... Exhaust gas sensor, 8
... Exhaust pipe, 9 ... Metering valve, 10 ... Mixing ratio detector, 11 ... Drive circuit, 12 ... Pressure regulator, 13 ... Filter, 14 ... Pump, 15 ...
... Fuel tank, 16 ... Fuel quantity meter, 17 ... Output device, 18 ... Input device, 19 ... Setting device, 20
... Microprocessor, 21, 28 ... Register, 22, 23, 24, 25, 26, 27 ... Storage device, 29 ... Power distributor, 30 ... Coil, 31
...Switch, 32...Power supply, 33...Solenoid valve,
34...Exhaust gas recirculation device (EGR), 35...Motor, 36...Current control circuit, X...Alcohol mixing rate, A/F...Air-fuel ratio, θ...Engine temperature, N...Engine rotation Speed, n...Engine speed, y...Load, k...Fuel modification coefficient, λ...
...Excess air ratio, t...Cranking duration time.

Claims (1)

[Scope of Claims] 1. A first storage device that stores an optimum air-fuel ratio related to the rotational speed and load of the engine, and an air flow meter that detects the intake air amount of the engine;
A microprocessor that calculates a signal regarding the fuel amount from the output signal of the air flow meter and the optimum air-fuel ratio of the first storage device, and a second storage device that stores information regarding the properties of the fuel such as the alcohol contamination rate.
a storage device, and an input/output device for the microprocessor, which has a program for modifying the signal regarding the fuel amount using the information in the second storage device, and rewrites the information stored in the second storage device. The engine control device is provided with a program that modifies the signal regarding the amount of fuel according to the information from the second storage device and the change in engine temperature, and supplies the signal to the engine according to the alcohol mixing rate in the fuel. An engine control device characterized in that it is configured to determine an air-fuel ratio of an air-fuel mixture. 2. The second storage device is a device having a program that rewrites information based on a signal from the alcohol mixing rate detector installed in the fuel flow path upstream of the twist injection valve. The engine control device according to item 1. 3 The first storage device compares the excess air ratio detected by the exhaust gas sensor with the optimum air-fuel ratio or optimum excess air ratio of the first storage device,
2. The engine control device according to claim 1, which comprises a program for automatically feedback controlling the fuel amount so as to approach a set value, and a third storage device for storing the corrected value.