JPH07259598A - Fuel injection control device - Google Patents

Abstract

PURPOSE:To dispense with a negative pressure introduction passage by obtaining a ratio of a fuel injection amount between the fuel whose pressure is highered than the intake pressure by the specified value and the pressure whose pressure is highered than the atmospheric pressure by the specified value for correcting the fuel injection amount. CONSTITUTION:During operation of an engine, an ECU 21 determines a proper fuel amount according to an engine condition and a vehicle condition, and computes an injection time of a fuel injection valve 7. In order to inject a target amount which is adjusted in pressure with reference to atmospheric pressure, the fuel injection time must be corrected. As for the fuel adjusted in pressure with reference to an intake pressure, the injection amount is proportional to an opening time of the fuel injection valve 7. A ratio of the injection amount is obtained in the case that the fuel adjusted in pressure with reference to the atmospheric pressure and the fuel adjusted in pressure with reference to the intake pressure are injected simultaneously. The target injection time is corrected with the obtained ratio. An accurate injection amount is thus obtained irrespective of fluctuation of the intake pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for controlling injection of fuel into an intake passage of an engine.

[0002]

2. Description of the Related Art In a fuel injection control apparatus for an electronically controlled fuel injection type engine, an optimum fuel amount is determined according to the engine state, the vehicle state, etc., and a fuel injection valve (injector) provided in an intake passage is provided. ) Is controlled to achieve the injection of the fuel amount.

In such a fuel injection control device, the pressure of the fuel pumped from the fuel tank by the fuel pump is adjusted by the fuel pressure regulator and injection is performed by opening the needle valve of the injector.
Excess fuel is returned to the fuel tank through the return pressure pipe via the fuel pressure regulator.

Conventionally, in the fuel injection control by the injector, the reference pressure of the fuel pressure regulator is the surge tank internal pressure, and the fuel pressure is a pressure to which a constant pressure is added from the surge tank internal pressure, that is, the formula for calculating the fuel injection amount. By considering (P ₁ −P ₂ ) in the following equation (1) as a constant, the fuel injection amount Q is determined by the injector opening time t.
Was controlled by.

## EQU2 ## Q = αAt {2g (P ₁ −P ₂ ) / Y} ^1/2 (1) where Q: fuel injection amount g: gravitational acceleration α: flow coefficient P ₁ : fuel pressure A : Injector opening area P ₂ : Surge tank internal pressure t: Opening time Y: Fuel specific weight

On the other hand, it has been attempted to use a fuel system without a return pipe (returnless fuel system) in order to reduce the cost and prevent the evaporated gas. In that case,
The fuel pressure regulator will be located near the fuel tank. In that case, the reference pressure of the fuel pressure regulator must be something other than the surge tank internal pressure. In other words, if the surge tank internal pressure is used, a negative pressure pipe having a length corresponding to the return pipe must be extended to the fuel pressure regulator through the floor below the vehicle body, and there is no point in eliminating the return pipe. Therefore, a pressure other than the surge tank internal pressure must be used as the reference pressure, and it is considered to use atmospheric pressure as the pressure.

[0006]

However, when the reference pressure of the fuel pressure regulator is atmospheric pressure, (P ₁ -P ₂ ) in the above equation (1) does not become a constant, and fuel injection is performed by controlling the opening time of the injector. The quantity cannot be controlled. That is, when the surge tank internal pressure is adopted as the reference pressure, (P ₁ -P ₂ ) can be made constant regardless of the throttle opening as shown in FIG. 3, but the atmospheric pressure is adopted as the reference pressure. the, as shown in FIG. 4 when (P ₁
-P ₀ ) is not constant, and if the time control is performed as it is, there arises a problem that the fuel injection amount becomes insufficient at high load and the fuel injection amount becomes excessive at low load.

Incidentally, Japanese Utility Model Laid-Open No. 5-12463 discloses a technique in which a fuel pressure control valve is provided near a fuel tank, but this prior art controls the fuel pressure control valve according to intake pressure. It controls the fuel pressure itself, and is provided with a control circuit therefor, and the structure of the fuel pressure control valve itself is complicated.

[0008]

A structure of a fuel injection control device according to the present invention for solving the above-mentioned problems is a fuel pump for sucking and discharging fuel in a fuel tank, and a fuel pump for discharging fuel from the fuel pump. And a fuel injection valve for injecting fuel into the intake passage of the engine, and a part for returning the fuel to the fuel tank to adjust the pressure of the remaining fuel to a pressure higher than the actual atmospheric pressure by a predetermined pressure. And a fuel supply passage that communicates the fuel injection valve with the pressure adjusting means to supply the fuel whose pressure is adjusted by the pressure adjusting means to the fuel injection valve, and detects information about the intake pressure in the intake passage. The intake pressure information detecting means, the target injection time setting means for setting the target fuel injection time of the fuel injection valve based on the operating state of the engine, and the target injection time setting means. Correction means for correcting the target fuel injection time based on the intake pressure information detected by the intake pressure information detecting means, and control means for controlling the fuel injection valve based on the target fuel injection time corrected by the correction means It is characterized by being composed of and.

When the pressure of the fuel supplied to the fuel injection valve is set to be a pressure higher than the intake pressure in the intake passage by a predetermined pressure, the correction means sets the amount injected from the fuel injection valve in a predetermined time. The intake pressure information detected by the intake pressure information detecting means is the ratio to the amount injected from the fuel injection valve in the predetermined time when the pressure of the fuel is increased by a predetermined pressure from the atmospheric pressure. And the target fuel injection time is corrected based on the ratio.

In this case, the correction means obtains the ratio based on the deviation between the atmospheric pressure and the intake pressure in the intake passage.

Further, when the atmospheric pressure is P _O , the intake pressure is P ₂ and the predetermined pressure in the pressure adjusting unit is P _R , the correcting means calculates the ratio K _RL by the following equation (2).

Equation 3] _{K RL = 1 - {(P} O -P 2) / P R} , wherein the (1/2) are those obtained by (2).

An atmospheric pressure information detecting means for detecting information on the atmospheric pressure is further provided, and the atmospheric pressure used for calculating the ratio is a preset standard atmospheric pressure, and the correcting means detects the atmospheric pressure information. The above-mentioned ratio is corrected based on the atmospheric pressure information detected by the means.

Further, the fuel injection control device according to the present invention is
In the first-mentioned configuration, the intake air amount detecting means for detecting the intake air amount of the engine, and the engine speed detecting means for detecting the engine speed are further provided, and the intake pressure information detecting means is The intake pressure in the intake passage is estimated based on the intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine speed detecting means, and the estimated intake pressure is used as the intake pressure information. It is characterized by being detected.

In this case, it further comprises an atmospheric pressure information detecting means for detecting information relating to the atmospheric pressure, and the correcting means estimates by the intake information detecting means based on the atmospheric pressure information detected by the atmospheric pressure information detecting means. Correct the intake pressure,
The target injection time is corrected based on the corrected estimated intake pressure.

The correction means corrects the target fuel injection time based on the atmospheric pressure information detected by the atmospheric pressure information detection means and the corrected estimated intake pressure.

The target injection time setting means sets the target fuel injection time based on the intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine speed detecting means. Is characterized in that.

In the first-mentioned configuration, the target injection time setting means sets the target fuel injection time based on the intake pressure information detected by the intake pressure information detecting means.

In the first-mentioned configuration, the intake pressure information detecting means is a pressure sensor for detecting the intake pressure in the intake passage.

This pressure sensor further comprises atmospheric pressure information detecting means for detecting information relating to atmospheric pressure, and the correcting means detects the intake pressure detected by the intake pressure information detecting means and the atmospheric pressure information detecting means. The target fuel injection time is corrected based on the atmospheric pressure information detected by the means.

In the above structure, the intake pressure in the intake passage at a predetermined standard atmospheric pressure is stored in advance by using the predetermined operating state variable of the engine as a parameter, and the predetermined operating state variable of the engine. Of the intake pressure stored in the intake pressure storage means, the operating state variable detecting means detecting the operating state variable detecting means for detecting the value of the operating state variable detecting means. It is characterized in that the atmospheric pressure obtained based on the intake pressure corresponding to the value of the variable, the intake pressure detected by the intake pressure information detecting means, and the standard atmospheric pressure is used as the atmospheric pressure information.

The target injection time setting means sets the target fuel injection time based on the intake pressure detected by the intake pressure information detecting means, and when the intake pressure information detecting means is out of order, the intake pressure information is detected. Among the intake pressures stored in the storage means, the target fuel injection time is set based on the intake pressure corresponding to the value of the operating state variable detected by the operating state variable detecting means. .

[0022]

In the fuel injection control device having the above structure, since the reference pressure of the pressure adjusting means is atmospheric pressure, the target fuel injection time obtained based on the operating state of the engine is used as it is to control the fuel injection valve. In this case, the target fuel injection time is corrected based on the intake pressure information detected by the intake pressure information detecting means, so that an appropriate amount of fuel can be injected. Done.

In the fuel whose pressure is adjusted with reference to the intake pressure, the fuel injection amount is proportional to the opening time of the fuel injection valve. Therefore, the fuel whose pressure is adjusted with reference to the atmospheric pressure and the pressure with reference to the intake pressure are used. Even if the fuel is adjusted in pressure based on the atmospheric pressure, the ratio of the injection amount when the fuel is adjusted for the same time is calculated and the ratio of the target injection time is corrected. An accurate fuel injection amount can be obtained regardless of changes in atmospheric pressure.

Since the ratio is set based on the atmospheric pressure and the intake pressure, if the atmospheric pressure is a measured value, a more accurate fuel injection amount corresponding to the fluctuation of the atmospheric pressure can be obtained and fixed. The value can also be a specification mainly according to the environment of the area where the engine is operated.

The above ratio can be obtained by the above equation (2), and by this equation (2), an accurate fuel injection amount can be obtained more easily.

When the atmospheric pressure information detecting means is provided, the atmospheric pressure used to calculate the ratio can be set to a predetermined standard atmospheric pressure, and only the intake pressure can be calculated in advance as a parameter and stored as a map. Further, by correcting the ratio read from the map based on the atmospheric pressure information, it is possible to obtain an accurate fuel injection amount corresponding to the fluctuation of the atmospheric pressure.

If the intake air pressure detecting means and the engine speed detecting means are provided, the intake pressure can be estimated based on the intake air amount and the engine speed, and it is necessary to provide a sensor for detecting the intake pressure. Disappear.

In this case, by correcting the estimated intake pressure based on the atmospheric pressure information, it is possible to eliminate the estimation error of the intake pressure due to the fluctuation of the atmospheric pressure.

That is, by correcting the fuel injection time based on the atmospheric pressure and the estimated intake pressure, it is possible to obtain a more accurate fuel injection amount corresponding to the fluctuation of the atmospheric pressure.

The target injection time setting means sets the target fuel injection time based on the intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine speed detecting means. In other words, when the fuel control is L-Jetronic, the intake air amount detecting means and the engine speed detecting means are used for setting the fuel injection time. It is not necessary to provide new detection means.

When the target injection time setting means sets the target fuel injection time based on the intake pressure information detected by the intake pressure information detecting means, that is,
When the fuel control is D-Jetronic, the detection value of the intake pressure information detecting means is used for setting the fuel injection time, and therefore it is not necessary to provide a new detecting means for correcting the injection time.

When a pressure sensor is used as the intake pressure information detecting means to directly detect the intake pressure, a more accurate fuel injection amount can be obtained.

In this case, when the atmospheric pressure information detecting means is provided in addition to the intake pressure information detecting means, the fuel injection time is corrected based on the atmospheric pressure and the intake pressure to cope with the fluctuation of the atmospheric pressure. Therefore, more accurate fuel injection control can be obtained.

If the intake pressure storing means is provided and the atmospheric pressure is obtained using the intake pressure and the standard atmospheric pressure stored in the intake pressure storing means, it is necessary to provide a sensor for obtaining the atmospheric pressure information. It is no longer necessary and only the intake pressure sensor is needed.

If the stored value stored in the intake pressure storage means is used for calculating the atmospheric pressure when the intake pressure information detection means fails, a new storage means for correcting the fuel injection time is required. Disappears.

[0036]

Embodiments of the fuel injection control device according to the present invention will now be described with reference to the drawings. FIG. 1 shows a schematic configuration of a fuel injection control device according to one embodiment. In FIG. 1, an intake pipe 3 is connected to a combustion chamber 2 of an engine 1, and the intake pipe 3 is supplied into the combustion chamber 2 by changing an opening of an intake passage 4 formed by the intake pipe 3. A throttle valve 5 for adjusting the intake air amount is provided. A surge tank 6 is formed on the downstream side of the throttle valve 5 as a part of the intake passage 4. A fuel injection valve 7 that injects fuel into the intake passage 4 is provided on the downstream end side of the intake pipe 3.

On the other hand, a fuel pump 9 is provided in a fuel tank 8 provided at the rear portion of the vehicle, and a fuel supply pipe 10 forming a fuel supply passage is provided in the fuel pump 9.
The fuel supply pipe 10 is connected to the delivery pipe 12 via the filter 11. The fuel injection valve 7 is connected to the delivery pipe 12.

The fuel supply pipe 10 branches near the fuel tank 8, and the return pipe 13 leading to the fuel tank 8 is connected through a fuel pressure regulator 14 which is a pressure adjusting means. The fuel pressure regulator 14 receives the fuel discharged from the fuel pump 9, and returns a part of the fuel to the fuel tank 8 to adjust the pressure of the fuel to a pressure higher than the actual atmospheric pressure by a predetermined pressure. In this configuration, the inside of the housing is divided into a fuel chamber and an atmospheric pressure chamber by a diaphragm, and the fuel supply pipe 10 side and the return pipe 1 are provided in the fuel chamber.
A valve for opening and closing the valve 3 is provided, and a spring for urging the valve in the closing direction is provided on the atmospheric pressure chamber side.

An air cleaner 15 is provided at the inlet of the intake pipe 3, and an air flow sensor 16 such as a Karman vortex meter is provided downstream of the air cleaner 15 as an intake air amount detecting means for detecting the intake air amount. . At the inlet of the intake pipe 3, an atmospheric pressure sensor 17 as atmospheric pressure information detecting means for measuring atmospheric pressure, and an intake temperature sensor 1 for measuring the temperature of intake air.
8 are provided. A pressure sensor 19 is provided downstream of the throttle valve 5 in the intake pipe 3 as an intake pressure information detecting means for detecting the absolute pressure of intake air. The throttle valve 5 is provided with a throttle position sensor 20 for detecting its position. Detection signals of these sensors 16, 17, 18, 19, 20 are sent to an electronic control unit (hereinafter, ECU) 21 as a control means. The engine speed and other information from an engine speed sensor (not shown) are also input to the ECU 21.

In the ECU 21, the optimum fuel amount is determined according to the engine condition and the vehicle condition, and the injection time of the fuel injection valve 7 is calculated based on it, but the reference pressure of the fuel pressure regulator 14 is the atmospheric pressure. In the fuel injection time when the internal pressure of the surge tank is used as the reference pressure, when the fuel is directly injected, the fuel amount becomes excessive or insufficient. That is, in order to inject the target amount of the fuel whose pressure is adjusted with reference to the atmospheric pressure, it is necessary to correct the fuel injection time and adjust the fuel injection amount to an appropriate amount.

When the reference pressure of the fuel pressure regulator 14 is the internal pressure of the surge tank, the fuel injection amount Q is obtained by the above equation (1). The fuel injection amount Q'when the reference pressure of the fuel pressure regulator 14 is atmospheric pressure is obtained by the following equation (3).

[Equation 4] Q ′ = αAt {2g (P ₀ + P _R −P ₂ ) / Y} ^1/2 (3) where P _R : Fuel pressure regulator pressure

Therefore, the fuel amount ratio K _RL of both fuels at the same injection time (opening time) can be obtained by the following equation (4).

Equation 5] _{K RL = Q / Q '=} αAt {2g (P 1 -P 2) / Y} 1/2 / αAt {2g (P 0 + P R -P 2) / Y} 1/2 = {( _{P 0 + P R -P 2)} / P R} -1/2 = {1 + (P 0 -P 2) / P R} -1/2 ··· (4)

When the equation (4) is expanded by the binomial theorem, it is approximated as the following equation (5).

## _EQU6 ## K _RL = 1-{(P ₀ −P ₂ ) / P _R } (1/2) (5)

Therefore, when the reference pressure of the fuel pressure regulator 14 is atmospheric pressure, in order to obtain the fuel injection amount Q determined according to the engine state and the vehicle state, the injection time (opening time) is corrected by the above coefficient. Thus, the target injection time (opening time) t'is obtained. As a result, the fuel injection valve 7 is controlled to open, and the fuel of the injection amount Q is injected into the intake passage 4. That is, even if the reference pressure of the fuel pressure regulator 14 is set to the atmospheric pressure, the fuel injection amount can be controlled in time, and further, the error of the fuel injection amount due to the pressure fluctuation in the intake passage 4 can be eliminated.

In this embodiment, the above calculation is performed by the ECU 21. That is, the ECU 21 constitutes the target injection time setting means and the correction means. The flow of calculation and processing in the ECU 21 in the above embodiment is schematically shown in FIG.

As described above, when the atmospheric pressure sensor 17 and the pressure sensor 19 are provided, the atmospheric pressure and the intake pressure at that time can be directly obtained, and therefore the ratio K _RL obtained by the above equation (5) is used as it is. The fuel injection time may be corrected by using this.

As the atmospheric pressure, a preset standard atmospheric pressure can be used. However, in that case, since the atmospheric pressure changes depending on the weather conditions and the height of the traveling place, it is necessary to correct the injection amount ratio K _{RL based} on the atmospheric pressure information obtained by the atmospheric pressure sensor 17. For example, when the fuel control is L-Jetronic and the atmospheric pressure sensor 17 is not provided, when the injection amount ratio K _RL is obtained at the standard atmospheric pressure, the injection amount is adjusted according to the change in atmospheric pressure. The ratio K _RL needs to be corrected.

That is, the atmospheric pressure correction coefficient is K_APThen,
P₀= P₀× K_AP, P₂= P₂× K _APBecause
{(P₀−P₂) / P_R} (1/2) is K_RL′ Is A /
N (intake air amount / engine speed) and engine speed
Set with the map according to the above, and correct and approximate equation (5) above.
And it becomes like the following formula.

## _EQU00007 ## K _RL = {1 + K _AP (P ₀ -P ₂ ) / P _R } ^-1/2 = 1- {K _AP (P ₀ -P ₂ ) / P _R } (1/2) ... (6) = 1-K _AP × K _RL ′ (7) In this case, K _RL ′ with only the intake pressure as a parameter is calculated in advance, stored as a map, and read from the map. K _RL may be obtained by correcting the ratio with the atmospheric pressure correction coefficient.

In both the calculation and the map, if the basic injection time set at the standard atmospheric pressure in the fuel injection control is T _B and the corrected fuel injection time is T _B ′,
T _B 'is represented by the following equation (8).

(8) T _B ′ = T _B × K _RL (8)

Further, instead of directly detecting the intake pressure in the intake passage 4, the intake pressure is estimated based on the intake air amount detected by the air flow sensor 16 and the engine speed detected by the engine speed sensor. However, this can also be used as the intake pressure information. The portion that performs this estimation calculation functions as the intake pressure information detection means.
In this case, it is not necessary to provide the pressure sensor 19. Further, as described above, this estimated value is calculated by the atmospheric pressure sensor 17
By making correction based on the atmospheric pressure information by, the estimation error of the intake pressure due to the fluctuation of the atmospheric pressure can be eliminated.

Further, the fuel control is D-Jetroni.
In the case of c), since only the intake pressure by the pressure sensor (MAP sensor) 19 which is the intake pressure information detecting means can be obtained, it is necessary to estimate and correct the atmospheric pressure. This guess is
Output value of MAP sensor 19 and pseudo M when MAP sensor 19 fails
Use AP output value. That is, if the output value of the MAP sensor 19 is P _MAP and the pseudo MAP output value (θ-Ne value) at the time of failure of the MAP sensor 19 obtained from the opening of the throttle valve 5 and the engine speed is P _THETA-NE , P ₀ x K _AP = 76
0 mmHg × (P _MAP / P _THETA-NE ), P ₂ × K _AP = P _MAP
Then, the above equation (6) is as follows.

[Equation 9] K _RL = 1- {760 mmHg × (P _MAP / P _THETA-NE ) −P _MAP } / P _R / 2 = 1 + {1- (760 mmHg / P _THETA-NE )} × P _MAP / P _R / 2 (9)

Therefore, according to the equation (9), the MAP sensor 19
The output value and the θ-Ne map value are diverted to K_RLTo get
You can Therefore, during basic injection set at standard atmospheric pressure
Interval T _BThis ratio K_RLFuel injection based on atmospheric pressure
Time T_B′ Is required, and the fuel injection valve 7 is controlled to open.
It Such calculations and commands are not made in the ECU 21.
Be done.

[0053]

According to the fuel injection control device of the present invention, the fuel pump for sucking and discharging the fuel in the fuel tank, and the fuel discharged from the fuel pump for receiving a part of the fuel pump To adjust the remaining fuel pressure to a pressure higher than the actual atmospheric pressure by a predetermined pressure, a fuel injection valve for injecting fuel into the intake passage of the engine, the fuel injection valve and the above pressure. A fuel supply passage which communicates with the adjusting means and supplies the fuel whose pressure is adjusted by the pressure adjusting means to the fuel injection valve; and an intake pressure information detecting means for detecting information on the intake pressure in the intake passage, Target injection time setting means for setting the target fuel injection time of the fuel injection valve based on the operating state of the engine,
The target fuel injection time set by the target injection time setting means is corrected based on the intake pressure information detected by the intake pressure information detecting means, and the target fuel injection time is corrected by the correcting means. The fuel injection valve is constituted by the control means for controlling the fuel injection valve, and the fuel pressure is adjusted on the basis of the atmospheric pressure. Therefore, the negative pressure introducing passage from the intake passage unlike the conventional case is unnecessary, and the pressure adjusting means is provided. Since it is provided near the fuel tank and the return length of the fuel can be shortened, it is possible to reduce the cost and suppress the fuel evaporation. Further, by correcting the fuel injection amount based on the intake pressure information of the intake passage, it is possible to eliminate the error of the fuel injection amount due to the pressure fluctuation in the intake passage.

When the atmospheric pressure used to calculate the above ratio is a predetermined standard atmospheric pressure, it can be stored as a map calculated in advance using only the intake pressure as a parameter, and the ratio read from this map can be stored. By correcting with the atmospheric pressure information, it is possible to obtain an accurate fuel injection amount corresponding to the fluctuation of the atmospheric pressure.

If the intake pressure information detecting means estimates the intake pressure based on the intake air amount and the engine speed, it is not necessary to provide a sensor for detecting the intake pressure. If the estimated value is corrected by the atmospheric pressure information, it is possible to eliminate the estimation error of the intake pressure due to the fluctuation of the atmospheric pressure.

In the case of L-JETRO control and the like, if the target injection time setting means sets the target injection time by the intake air amount and the engine speed, a new detection means is provided for the injection time control. There is no need.

In the case of D-JETRO control or the like, if the target fuel injection time setting means sets the target injection time based on the intake pressure information, it is not necessary to newly provide a detecting means for controlling the injection time. .

If a sensor that directly detects the intake pressure in the intake passage is used as the intake pressure information detecting means, a more accurate fuel injection amount can be obtained.

An intake pressure storage means and an operating state variable detecting means are further provided, and the atmospheric pressure information detecting means and the intake pressure read from the intake pressure storing means based on the detection result of the operating state variable detecting means and the standard value. Since the atmospheric pressure information is obtained from the atmospheric pressure, it is not necessary to provide a sensor for obtaining the atmospheric pressure information.

Further, by using the stored value of the intake pressure storage means provided for fail-safe for the fuel injection setting for calculating the atmospheric pressure, it becomes unnecessary to provide new storage means for correcting the fuel injection time.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a fuel injection control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of calculation and processing according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of fuel pressure based on a conventional surge tank internal pressure.

FIG. 4 is an explanatory diagram of pressure fluctuation in the case of fuel pressure control based on atmospheric pressure.

[Explanation of symbols]

 1 engine 4 intake passage 5 throttle valve 6 surge tank 7 fuel injection valve 8 fuel tank 9 fuel pump 10 fuel supply pipe 13 return pipe 14 fuel pressure regulator 16 air flow sensor 17 atmospheric pressure sensor 18 intake air temperature sensor 19 pressure sensor 21 electronic control unit

Claims (14)

[Claims] 1. A fuel pump that sucks and discharges fuel in a fuel tank, and a fuel pump that receives the fuel discharged from the fuel pump and returns a part of the fuel to the fuel tank so that the pressure of the remaining fuel is actually measured. A pressure adjusting means for adjusting the pressure to a pressure higher than the atmospheric pressure by a predetermined pressure, a fuel injection valve for injecting fuel into the intake passage of the engine, the fuel injection valve and the pressure adjusting means are communicated with each other, and the pressure is adjusted by the pressure adjusting means. A fuel supply passage for supplying the adjusted fuel to the fuel injection valve,
Intake pressure information detecting means for detecting information about intake pressure in the intake passage, target injection time setting means for setting a target fuel injection time of the fuel injection valve based on the operating state of the engine, and target injection time setting Correction means for correcting the target fuel injection time set by the means based on the intake pressure information detected by the intake pressure information detecting means,
A fuel injection control device comprising: a control unit that controls the fuel injection valve based on the target fuel injection time corrected by the correction unit. 2. The correcting means injects fuel from the fuel injection valve at a predetermined time when the pressure of the fuel supplied to the fuel injection valve is set to be a pressure higher than the intake pressure in the intake passage by a predetermined pressure. The ratio between the amount and the amount injected from the fuel injection valve in the predetermined time when the pressure of the fuel is increased by a predetermined pressure above the atmospheric pressure is determined by the intake pressure detected by the intake pressure information detecting means. Obtained based on atmospheric pressure information,
The fuel injection control device according to claim 1, wherein the target fuel injection time is corrected based on the ratio. 3. The fuel injection control device according to claim 2, wherein the correction means obtains the ratio based on a deviation between the atmospheric pressure and the intake pressure in the intake passage. 4. The correcting means sets the atmospheric pressure to P _O , the intake pressure to P ₂ , and the predetermined pressure in the pressure adjusting means to P _R.
4. The fuel according to claim 3, wherein the ratio K _RL is obtained by the following equation: K _RL = 1 − {(P _O −P ₂ ) / P _R } (1/2) Injection control device. 5. An atmospheric pressure information detecting means for detecting information on the atmospheric pressure is further provided, and the atmospheric pressure used for calculating the ratio is a standard atmospheric pressure set in advance, and the correcting means comprises:
4. The fuel injection control device according to claim 3, wherein the ratio is corrected based on the atmospheric pressure information detected by the atmospheric pressure information detecting means. 6. An intake air amount detecting means for detecting an intake air amount of the engine, and an engine speed detecting means for detecting an engine speed of the engine, wherein the intake pressure information detecting means is the intake air. Estimating the intake pressure in the intake passage based on the intake air amount detected by the amount detecting means and the engine speed detected by the engine speed detecting means, and detecting the estimated intake pressure as the intake pressure information. The fuel injection control device according to claim 1. 7. An atmospheric pressure information detecting means for detecting information related to atmospheric pressure, wherein the correcting means estimates the intake pressure by the intake information detecting means based on the atmospheric pressure information detected by the atmospheric pressure information detecting means. The fuel injection control device according to claim 6, wherein the target injection time is corrected based on the corrected estimated intake pressure. 8. The correcting means corrects the target fuel injection time based on the atmospheric pressure information detected by the atmospheric pressure information detecting means and the corrected estimated intake pressure. The fuel injection control device described. 9. The target injection time setting means sets the target fuel injection time based on the intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine speed detecting means. The fuel injection control device according to claim 6, wherein 10. The fuel injection control according to claim 1, wherein the target injection time setting means sets the target fuel injection time based on intake pressure information detected by the intake pressure information detecting means. apparatus. 11. The fuel injection control device according to claim 1, wherein the intake pressure information detecting means is a pressure sensor for detecting an intake pressure in the intake passage. 12. An atmospheric pressure information detecting means for detecting information on atmospheric pressure, wherein the correcting means detects an intake pressure detected by the intake pressure information detecting means and an atmospheric pressure information detected by the atmospheric pressure information detecting means. The target fuel injection time is corrected based on the atmospheric pressure information.
1. The fuel injection control device according to 1. 13. Intake pressure storage means for storing in advance the intake pressure in the intake passage at a predetermined standard atmospheric pressure using a predetermined operating state variable of the engine as a parameter, and a value of the predetermined operating state variable of the engine. The atmospheric pressure information detecting means detects the operating state variable detected by the operating state variable detecting means among the intake pressures stored in the intake pressure storing means. The atmospheric pressure obtained based on the intake pressure corresponding to the value of, the intake pressure detected by the intake pressure information detecting means, and the standard atmospheric pressure is used as the atmospheric pressure information. Fuel injection control device. 14. The target injection time setting means sets the target fuel injection time based on the intake pressure detected by the intake pressure information detecting means, and when the intake pressure information detecting means is out of order, the intake pressure 14. The target fuel injection time is set based on the intake pressure corresponding to the value of the operating state variable detected by the operating state variable detecting means out of the intake pressure stored in the storage means. 7. The fuel injection control device according to.