JP2702305B2 - Engine fuel control method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling fuel supplied to an engine.

[0002]

2. Description of the Related Art In order to control the A / F (air-fuel ratio) of an engine with high accuracy, it is necessary to consider the amount of fuel that is injected into an intake pipe and adheres to the intake pipe wall. In other words, the fuel adhesion rate changes depending on the temperature of the intake pipe wall, and the adhesion rate increases during acceleration, while the negative pressure in the intake pipe increases during deceleration, which increases the amount of evaporation of the attached fuel. As a result, the amount of movement of the fuel flowing from the intake pipe into the cylinder changes, and this change in the amount of movement causes the A / F control to fluctuate.

[0003] In consideration of the above, conventionally, as disclosed in Japanese Patent Publication No. 60-50974, the amount of fuel adhering to the intake pipe wall surface is determined based on parameters indicating the load state and the warm-up state of the engine. For example, the predicted amount is added to the basic fuel amount as a correction amount.
As disclosed in Japanese Patent No. 8834, an amount of fuel for combustion is calculated from exhaust gas using an A / F sensor, and the difference between the amount of fuel supplied to the intake pipe and the amount of fuel for combustion is calculated based on the difference between the amount of fuel and the amount of fuel for combustion. The amount of fuel adhering to the engine is calculated, and the amount of adhering fuel is corrected in accordance with the wall temperature state calculated from the throttle opening and the temperature of the engine cooling water.

[0004]

The above-described means for compensating the amount of fuel adhesion is effective in increasing the accuracy of A / F control. By the way, among these prior arts, in the former case, the throttle valve opening is not considered as load information for obtaining the fuel adhesion amount, but a so-called single point injection in which a fuel injection valve is arranged upstream of the throttle valve. In the system (SPI) system, the amount of fuel adhering to the intake pipe wall of the engine is not always sufficient because it is greatly affected by the opening of the throttle valve as described later .

In the latter case, a high-precision exhaust gas air-fuel ratio sensor is used to calculate the amount of fuel for combustion from exhaust gas and calculate the amount of fuel adhesion from the difference between the amount of fuel and the amount of fuel actually injected. Is required, the cost is increased in practical use, and the operation system of the system tends to be complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to reduce cost, for example, by using SPI.
It is an object of the present invention to enable high-precision fuel adhesion compensation, and thus A / F control, even in such a case.

[0007]

In order to achieve the above-mentioned object, the following problem solving means is proposed.

That is, the first means for solving the problem relates to a fuel control method which is a basis of the present invention, and includes a method for detecting a load state of an engine when controlling a fuel amount according to an operation state of the engine. 2 of signal and detection signal about warm-up state
A first correction amount of fuel adhering to the intake pipe wall is calculated with the two parameters, and a throttle valve opening detection signal for adjusting the intake air quantity of the engine and a detection signal relating to the warm-up state are calculated to the intake pipe wall using two parameters. A second correction amount of the adhering fuel is calculated, and a correction amount corresponding to the intake pipe wall adhering fuel amount during a transient operation such as acceleration or deceleration is obtained from the sum of the first and second correction amounts. The amount is added to the basic fuel amount calculated from various sensor input values related to engine operation.

The second object of the present invention relates to an invention of an apparatus to which the above-described fuel control method is applied. The contents include (a) means for detecting a load state of an engine, and (b) means for detecting an intake air amount of the engine. Means for detecting a throttle valve opening to be controlled;
Means for detecting a warm-up state of the engine; (d) a calculation program for a basic fuel amount calculated based on detection signals from various sensors relating to the operation of the engine; and intake air defined by a relationship between a load state and a warm-up state of the engine. Means for storing a first fuel adhesion amount map on the pipe wall, a second fuel adhesion amount map determined based on a relationship between the throttle valve opening and the warm-up state, and the like; The calculation and the detection signals of the load state of the engine, the warm-up state, and the opening degree of the throttle valve, which are taken in at fixed time intervals, are compared with the first fuel adhesion map and the second fuel adhesion map, and the fuel corresponding to each map is compared. A fuel control device comprising: a means for obtaining an adhesion correction amount, adding these correction amounts to the basic fuel amount, and calculating a fuel injection pulse width corresponding to the supplied fuel amount.

[0010]

In the transient operation (acceleration, deceleration, etc.) in which the operating state of the engine changes, the amount of fuel adhering to the intake pipe wall changes. This fuel adhesion amount is also affected by the warm-up state of the engine, in other words, the temperature of the intake pipe wall.

FIG. 5 shows, by way of example, the A / F, the intake pipe pressure, and the throttle valve opening at the time of acceleration operation when the correction of fuel adhesion is made zero for an SPI type engine.

As shown by the solid line in FIG. 5, during acceleration, the change in the intake pipe pressure (change from negative pressure to approaching atmospheric pressure) at the initial stage is steep, and at this time, the fuel adhesion on the intake pipe wall is caused by the intake air. The change in the pipe pressure and the warm-up state (intake pipe wall temperature) at that time have a great effect, and the A / F suddenly becomes lean due to an increase in the fuel adhesion rate. Also, as the opening of the throttle valve increases, the pressure in the intake pipe saturates in a state close to the atmospheric pressure.
However, even if this intake pipe pressure is saturated,
As you open further (depress the accelerator), fuel
The adhesion ratio increases, and the A / F changes to the lean side. The reason
The reasons are described below. The throttle valve opening is described in FIG.
The dashed line indicates that the throttle valve is open until the intake pipe pressure saturates.
Indicates the state where the user has depressed, and the broken line described in the A / F
Shows the A / F behavior at that time. If the fuel
The amount of adhesion depends only on the intake pipe pressure and the intake pipe wall temperature.
Then, (a) press the accelerator so that the throttle valve opening becomes a solid line.
When stepping on and stepping on (b) as shown by the broken line
In both cases, the behavior of the A / F should behave like a dotted line.
However, in the case of (a), the A / F is actually
The behavior shown by the solid line, and the behavior shown by the broken line in (b)
And both are not the same. That is, the intake pipe pressure
After the throttle is saturated, continue to depress the accelerator to reduce the throttle valve opening.
While open, the A / F increases in the lean direction. So
The following can be considered as reasons for the above. That is, FIG.
In the SPI type engine as shown in
Is injected around the throttle valve. Intake
If the throttle valve opening is further depressed after the pipe pressure is saturated
The intake air volume hardly changes, but the throttle valve
Since the mouth area changes, the amount of fuel adhesion
Have a significant effect. (1) Even if the intake air amount is the same, the smaller the throttle valve opening, the earlier
The air flow passing around the throttle valve due to the small opening area
Speed is faster. The injected fuel is mixed with intake air and throttled.
Because the air flows around the valve, the faster the flow rate of the intake air
The fuel is easy to get into the air flow (fuel adhesion is reduced). Paraphrase
If the throttle valve opening is large (the one with a low intake flow rate)
The amount of fuel adhering to the intake pipe wall increases. (2) As shown in FIG.
The injected fuel flows toward the bottom of the intake pipe downstream of the throttle valve.
Since it is once sprayed, it easily adheres to the intake pipe wall .
If the throttle valve opening is small, the fuel rides on the airflow
The fuel flows toward the openings on both sides of the throttle valve, and the fuel on it also throttles.
Because it does not go directly to the bottom of the intake pipe downstream of the
The amount of fuel adhering to the tracheal wall is reduced. The figure
After the acceleration is completed as shown in Fig. 5, the throttle valve opening is
A / F even when the opening to maintain the saturation pressure is continued
Decays to the state before acceleration, but this is because the fuel is almost constant
While the fuel injection rate and the fuel injection rate are flat,
As the incoming fuel flows into the engine cylinders,
A / F is gradually lower due to balance with fuel flowing into engine
It is because it becomes a fixed state.

In the first means for solving the problems, during the acceleration operation as described above, a detection signal (for example, an intake pipe pressure detection signal) of an engine load state and a detection signal (for example, an engine cooling water temperature detection signal) relating to a warm-up state are provided. The first correction amount calculated from the two parameters mainly compensates for fuel adhesion due to a change in the intake pipe pressure in the initial stage of acceleration, and compensates for fuel adhesion as the throttle valve opening progresses thereafter, by detecting the throttle valve opening. The second correction amount calculated from the two parameters of the signal and the detection signal related to the warm-up state is mainly performed.

The fuel adhesion correction amount based on the sum of the first and second amounts is an acceleration correction pulse (solid line) as shown in FIG. 6, and the amount of fuel increase by the correction is represented by the lean A / F shown in FIG. The waveform can be approximated (the broken curve in FIG. 6 is a waveform when the second correction amount based on the throttle valve opening is set to zero, and represents only the first correction amount).

As a result, the appropriate A / F depends on the corrected fuel amount.
Can be suppressed.

Although the fuel adhesion at the time of deceleration is not shown, in this case, the fuel adhering to the intake pipe evaporates (in other words, the fuel adhesion rate becomes negative), and the fuel adhesion compensation is performed. If there is no A / F, the A / F tends to be rich.
Therefore, if the correction amount based on the two parameters of the detection signal related to the load state and the warm-up of the engine and the correction amount based on the two parameters of the detection signal related to the opening degree of the throttle valve and the warm-up are set to minus values, the negative value during deceleration is obtained. Compensation for fuel adhesion is also made with good accuracy.

The operation of the second problem solving means has been described in detail in the embodiment section with reference to the flow chart of FIG. 2, and the description thereof will be omitted. In the section of the embodiment, the engine intake pipe pressure sensor is used as the means (A), the engine coolant temperature sensor 13 is used as the means (B), and the throttle sensor 10 is used as the means (C). The ROM of the control unit 15 is used as means (d), and the means (e) is
The CPU of the control unit 15 is used.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows an example of an engine control system to which the present invention is applied. In the figure, reference symbol E denotes an engine, and a part of the intake air of the engine E flows into a bypass passage 2 after passing through an air cleaner 1. The flow rate is measured by the intake sensor 3.

The fuel in the fuel tank 4 is pressurized by a fuel pump 5, adjusted to a predetermined fuel pressure by a pressure regulator 6, and supplied to an injector (fuel injection valve) 7. In this embodiment, as apparent from the drawing, the injector 7 is connected to the throttle valve 9.
Is a so-called SPI system arranged upstream of the system.

As will be described in detail later, the injector 7
The valve opening control is sequentially performed in synchronization with the signal of the crank angle sensor 18 for the time of the injection pulse width Ti calculated by the control device (control unit) 15 or in synchronization with the signal at a constant period such as when the engine acceleration is detected. The fuel is injected into the intake air.

Reference numeral 9 denotes a throttle valve for adjusting the amount of intake air of the engine E. The throttle valve 9 is provided with a throttle sensor 10, and a throttle valve opening signal from the throttle sensor is also input to the control device 15. The control device 15 checks the signal from the throttle sensor 10 in a predetermined time unit, determines whether the control state of the engine is accelerating or decelerating based on the amount of change, or compares the control state with the predetermined value to determine whether the engine is in the idling state or the high load state. Is determined.

Reference numeral 11 denotes an auxiliary air supply device which has a function of controlling the area of a bypass passage connecting the upstream and downstream of the throttle valve 9 with an electric signal. In addition to the feedback control of the speed, a change in the rotation speed caused by a load change by an auxiliary device such as an air conditioner is compensated.

Reference numeral 12 denotes an ignition coil. A REF signal (engine rotation signal) is input from a crank angle sensor including a rotor 17 and a detector 18 incorporated in the distributor 16 to the controller 15, and an ignition control signal is calculated based on the REF signal. The energization of the ignition coil 12 is controlled, and a high pressure for ignition is supplied to a predetermined ignition plug via a distributor 16.

A temperature sensor 13 detects the temperature of the cooling water of the engine E, and a detection signal is input to the control device 15. Reference numeral 14 denotes an O ₂ sensor for detecting an air-fuel ratio, which is used for generating an air-fuel ratio control signal described later, and is used for feedback-controlling the air-fuel ratio. When this air-fuel ratio feedback control is performed, the engine speed is determined from the intake air amount signal Qa from the intake air amount sensor 3 and the engine rotation speed N obtained based on the REF signal from the crank angle sensor including the rotor 17 and the detector 18. Calculates the basic fuel injection pulse width (fuel amount) Tp required in each of the various operating states, adds a correction pulse TACC relating to the amount of fuel adhering during transient operation such as acceleration and deceleration to this pulse width Tp, By multiplying the air-fuel ratio control signal K by a predetermined correction coefficient COEF created based on signals from various sensors informing the engine parameters and adding the invalid pulse width Ts, the injection pulse width of the following equation (1) is obtained. Ti is obtained and supplied to the injector 7.

[0026]

## EQU00001 ## Ti = (Tp + TACC) .COEF.K + Ts (1) Here, compensation for fuel adhesion will be described with reference to FIGS.

FIG. 5 shows A / A when the fuel adhesion compensation is not performed during the acceleration operation, as already described in the section of the operation of the invention.
The relationship between F, the intake pipe pressure, and the throttle valve opening is shown. In the initial stage of acceleration, the change in the intake pipe pressure (change from negative pressure to approaching atmospheric pressure) is steep, and fuel adhesion on the intake pipe wall at this time is caused by intake The change in the pipe pressure and the warm-up state (intake pipe wall temperature) at that time have a great effect, and the A / F suddenly becomes lean due to an increase in the fuel adhesion rate. Further, as the opening of the throttle valve increases, the amount of adhesion to the intake pipe wall increases, and the A / F becomes lean accordingly.

Although not shown, during deceleration operation, when the negative pressure of the intake pipe pressure increases, the evaporation of fuel adhering to the pipe wall increases, and if fuel adhesion compensation is not performed, the A / F becomes Tends to be rich.

[0029] Figure 3 is a correction map according to the fuel adhesion amount created by focusing on the above phenomenon, FIGS. 3 (a) is a first fuel adhesion amount relative to the intake pipe pressure (first correction amount), FIG.
(B) is the second fuel adhesion amount (second
Respectively, for the correction amount) to indicate the relationship between the engine coolant temperature (warm-up state). FIG. 3 for calculating a second correction amount
The correction map of (b) is also described in the section of the operation of the invention.
In other words, the correction is made by opening the throttle valve after the intake pipe pressure is saturated.
To deal with fuel deposits that are affected by temperature
Therefore, the correction amount when the intake pipe pressure is saturated is stored.
ing. These correction maps correspond to the RO of the fuel control device 15.
M.

FIG. 4 (a) is a table relating to a first correction coefficient K1 for fuel adhesion due to a change in intake pipe pressure, and FIG. 4 (b) is a table relating to a second correction coefficient K2 for fuel adhesion due to a change in a valve opening. Each is determined in relation to the engine cooling water temperature,
It is stored in the ROM. The correction coefficients K1 and K2 are
A correction amount TAC1 described later (complement of the first fuel adhesion amount in FIG.
The first correction amount based on the positive map), TAC2 (FIG. 3B)
(Second correction amount based on second fuel adhesion amount correction map)
This has been exemplified as a means for attenuating. This damping means
The reasons for using the correction coefficients K1 and K2 are as follows.
You. FIG. 5 is described in the section of “action” in the specification.
Acceleration operation as described above for PI engine
Sometimes, while the intake pipe pressure and throttle valve opening are changing, A /
The degree of lean of F increases, and the intake pipe pressure and throttle
A / F lean after the change in valve opening
Decays to the state before the acceleration operation. Therefore, on
To correct the amount of fuel adhesion in response to the change in A / F
In this case, the correction of the fuel adhesion amount during acceleration is performed using the lean A / F.
Considering even the degree of attenuation, the correction accuracy will be higher
Confuse. The acceleration correction pulse indicated by the solid line in FIG.
As the fuel pressure increases due to changes in pipe pressure and throttle valve opening,
Lean behavior of A / F after their change disappears
Fuel amount correction (acceleration correction)
Pulse) in the relationship between intake pipe pressure and throttle valve opening
Therefore, the acceleration correction pulse eliminates the change in the throttle valve opening.
After that, it is attenuated to 0 (the behavior of A / F in
Approximate). The correction coefficients used for this attenuation are K1 and K2.
is there. In addition, as described in FIG.
Is determined according to the engine coolant temperature.
Similarly, the attenuation of the acceleration correction pulse is strongly affected by the engine coolant temperature.
This is because it depends.

Next, the A / F control of this embodiment will be described with reference to the flowchart of FIG.

The calculation procedure shown in the flowchart is stored in a read-only memory (ROM) in the control unit 15 shown in FIG. Central control unit (CPU)
According to the calculation procedure stored in the ROM, each sensor output is read from the analog port and the digital port, the injection pulse width is calculated and the injection pulse is output from the output port, and the injector is opened and closed to be supplied to the engine. Control the fuel. 200 to 21 in FIG.
Reference numeral 6 denotes a step. In steps 200 to 203, the throttle valve opening, engine coolant temperature, engine speed, and intake pipe pressure are read, and the basic fuel pulse width Tp is calculated from the intake pipe pressure and engine speed (204).
Further, a correction coefficient is obtained from the water temperature or the like, and the sum C of the correction coefficients is obtained.
The OEF is calculated (205).

Next, FIG. 3 (a) written in the ROM in the control unit of FIG. 7 from the intake pipe pressure and the water temperature.
(206).

For example, during the acceleration operation, the first adhesion amount D corresponding to the intake pipe pressure P (i-1) retrieved 10 ms before.
From (i-1), a change amount ΔD1 of the first adhesion amount D (i) corresponding to the current intake pipe pressure P (i) is obtained (20).
7). Next, the first correction amount TAC1 is calculated by this ΔD1 .
It is calculated (208). Here the intake pipe pressure saturates and
It was determined that the change amount ΔD1 of the accompanying fuel adhesion amount did not change.
In this case, the correction coefficient (decreased) is added to the previously calculated TAC1.
TAC1 multiplied by the decay coefficient K1 is calculated (20
9, 210).

Similarly, for the throttle valve opening degree, the second fuel adhesion amount map shown in FIG. 3B is searched (21 1 ) and 10 ms.
The second adhesion amount D corresponding to the previous throttle valve opening degree t (i-1)
From (i'-1), a change amount ΔD2 of the second adhesion amount D (i ') corresponding to the current throttle valve opening degree t (i) is obtained (21).
2 ). Next, the second correction amount TAC2 is calculated by the ΔD2.
It is calculated (213). Here, the change in throttle valve opening is flat
And the change amount ΔD2 of the second fuel adhesion amount is determined to be no change.
If set, correct to TAC2 calculated before
TAC2 is calculated by multiplying by a coefficient (attenuation coefficient) K2
(214,215).

The first and second correction amounts TAC1,
Calculates the sum of TAC2, the acceleration correction pulse TACC (21 6)

[0037] In step 21 7, the basic injection pulse width T
p, sum COEF of each correction coefficient, and acceleration correction pulse width T
The injection pulse width Ti is calculated from ACC and the invalid injection pulse width Ts (Ts is the maximum value of the injection pulse width of the spirit as shown in FIG. 8), and the output of the control unit 15 is output as shown in FIG. Ti time only to open the injector from the port (21 8).

The waveform of the acceleration correction pulse obtained through the above flow is shown by the solid line in FIG. This acceleration correction pulse is
In the initial stage of acceleration, the first correction amount TAC1 based on the suction negative pressure is effective, and in the middle and latter stages of acceleration, the second correction amount TAC2 based on the throttle opening is effective, and the waveform approximates to the A / F waveform in FIG. (Note that the broken line in FIG. 6 indicates the second
The waveform when the correction amount TAC2 is zero is shown only for the first correction amount.)

Although the above flow has been described for the acceleration correction, the same applies to FIGS. 3 (a) and 3 (b) when decelerating.
The first and second fuel adhesion amount maps are searched. Since the differences ΔD1 and ΔD2 between the searched values are negative (minus) and work to reduce the injection pulse width Ti, the loss correction during deceleration can be accurately performed in the same manner as the correction during acceleration.

In the embodiment, the intake pipe pressure is used as a search parameter of the first adhesion amount map. However, the amount of mass air sucked per cylinder of the engine and the basic injection pulse described in the embodiment are used. The width Tp or the like may be used, and the temperature of the intake pipe wall may be directly taken as a parameter for the warm-up state.

The fuel amount compensation in this embodiment can be applied to engines other than the SPI system.

[0042]

As described above, according to the present invention, the compensation for the amount of fuel adhering to the intake pipe wall of the engine is performed by adjusting the parameters of the engine load state and the warm-up state, and the throttle valve opening degree and the warm-up state. By using two parameters, it is possible to use simple sensors such as intake pipe pressure sensor, throttle sensor, engine coolant temperature sensor, etc., and to compensate for it with high accuracy. In particular, fuel adhesion required during transient operation such as acceleration and deceleration Amount compensation, and thus A / F control, can be performed accurately at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an engine control system to which the present invention is applied.

FIG. 2 is a flowchart showing an operation of fuel control in the embodiment of the present invention.

FIG. 3 is an explanatory diagram relating to a fuel adhesion amount correction map used in the embodiment.

FIG. 4 is an explanatory diagram relating to a fuel adhesion amount correction coefficient table used in the embodiment.

FIG. 5 is an explanatory diagram showing the relationship between the A / F, the intake pipe pressure, and the throttle valve opening when the fuel adhesion compensation is not performed.

FIG. 6 is an explanatory diagram showing a relationship between an acceleration correction pulse, an intake pipe pressure, and a throttle valve opening when the fuel adhesion correction of the embodiment is performed.

FIG. 7 is an explanatory diagram showing components of a control unit used in the embodiment.

FIG. 8 is an explanatory diagram of an invalid pulse width used as an element of the fuel injection pulse width calculation of the embodiment.

[Explanation of symbols]

Reference numeral 3: intake amount sensor, 7: injector, 10: throttle sensor, 13: water temperature sensor, 15: control unit (fuel amount calculation means, calculation data storage means), E: engine.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yukinori Sano 2477 Kashimayatsu, Odai, Kojita, Ibaraki Prefecture Within Hitachi Automotive Engineering Co., Ltd. 2477 Kashima Yatsu 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Yoshiyuki Tanabe 2520 Oji Takaba, Katsuta, Ibaraki Pref. Hitachi, Ltd. Sawa Plant (72) Inventor Haruhiko Kobayashi Ibaraki 2520 Takada, Katsuta-shi Examiner, Yasuhisa Miyazaki, Sawa Plant, Hitachi, Ltd.

Claims (4)

(57) [Claims] When a fuel amount is controlled in accordance with an operation of an engine, a first correction of fuel adhering to an intake pipe wall is performed using two parameters, a detection signal of a load state of the engine and a detection signal of a warm-up state. A second correction amount of fuel adhering to the intake pipe wall is calculated based on two parameters of a throttle valve opening detection signal for adjusting the intake amount of the engine and a detection signal regarding a warm-up state of the intake pipe wall. Then, a correction amount corresponding to the amount of fuel adhered to the intake pipe wall during transient operation such as acceleration or deceleration is obtained from the sum of the first and second correction amounts, and the correction amount is calculated based on various sensor input values of the engine. A fuel control method for an engine, characterized in that it is added to a basic fuel amount. 2. The engine according to claim 1, wherein the detection signal of the load state of the engine is a detection signal of a pressure of an intake pipe of the engine or a detection signal of an amount of mass air taken into a cylinder. The engine fuel control method according to claim 1, wherein the detection signal is a detection signal of an engine cooling water temperature or a detection signal of an intake pipe wall temperature. (A) means for detecting the load condition of the engine; (b) means for detecting the opening of the throttle valve for controlling the intake air amount of the engine; and (c) means for detecting the warm-up state of the engine. And (d) a program for calculating a basic fuel amount calculated based on detection signals of various sensors relating to the operation of the engine, and a first fuel adhesion to an intake pipe wall determined based on a relationship between a load state and a warm-up state of the engine. Means for storing an amount map, a second fuel adhesion amount map determined based on a relationship between a throttle valve opening degree and a warm-up state, and (e) an engine for calculating a basic fuel amount by the calculation program and taking in at regular time intervals. The detection signals of the load state, the warm-up state, and the throttle valve opening degree are compared with the first fuel adhesion amount map and the second fuel adhesion amount map to determine a fuel adhesion correction amount corresponding to each map. Amount in addition to the basic fuel amount Fuel control apparatus for an engine is characterized in that a means for calculating a corresponding fuel injection pulse width to fuel quantity. 4. The engine according to claim 3, wherein the means for detecting the load state of the engine comprises one of an engine intake pipe pressure sensor and an engine intake air flow rate sensor, and the means for detecting the warm-up state of the engine comprises: An engine fuel control device comprising an engine cooling water temperature sensor or an intake pipe wall temperature sensor.