JPH09112320A - Fuel injection amount controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the control of fuel injection amount even if injection timing is changed and pressure at the end of an injector changes at the time of fuel injection, by correcting a correction coefficient according to the injection timing in changing the injection timing. SOLUTION: When intake simultaneous injection is conducted, pressure at the end of an injector does not meet predicted (estimated) pressure, therefore, correction amount P corresponding to a crank angle Tang is calculated. Target fuel injection time TAU is multiplied by a correction coefficient KFPC with a value after being corrected with the correction amount P to calculate final fuel injection time. As a result, the later the injection timing is, the more the pressure at the end of the injector becomes negative, however, the correction coefficient KFPC is corrected with the correction amount P corresponding to the crank angle Tang to prevent fuel injection time or fuel injection amount from increasing, thus causing air-fuel ratio not to be deviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for an internal combustion engine.

[0002]

2. Description of the Related Art In an electronically controlled fuel injection engine, a fuel injection valve is connected to a delivery pipe, and a pressure regulator is attached to the delivery pipe for adjusting the fuel pressure of the fuel injection valve. 62-1732
It is known as disclosed in No. 3. The pressure regulator is for keeping the difference between the pressure of fuel in the delivery pipe (hereinafter referred to as fuel pressure) and the intake pressure constant and preventing the fuel injection amount from changing with respect to the changing intake pressure. Then, for pressure regulation, the intake pressure is introduced into the back pressure chamber partitioned by the diaphragm of the pressure regulator.

By the way, when the temperature of the fuel in the delivery pipe or the fuel injection valve becomes high, fuel vapor is easily generated.
In such a state, there arises a problem that the startability and the idle stability are remarkably deteriorated especially when the engine is started. In order to solve this problem, a solenoid valve is provided in the middle of the passage connecting the pressure regulator and the intake pipe, and when the temperature of the fuel in the delivery pipe reaches a predetermined value or more, the solenoid valve is activated when the engine starts, The back pressure chamber of the pressure regulator is open to the atmosphere. By opening the pressure regulator to the atmosphere, the fuel pressure in the delivery pipe and the fuel injection valve is increased as compared with the case where the pressure regulator is connected to the intake passage. When the fuel pressure increases, the vaporization temperature of the fuel rises, so that the vapor of the fuel is prevented from being generated in the delivery pipe and the fuel injection valve, and the startability of the engine is improved.

As described above, conventionally, an electromagnetic valve is required for switching the back pressure of the pressure regulator, which causes a problem that the system becomes complicated and the reliability and cost increase. In order to solve this problem, the applicant has already opened the back pressure chamber of the pressure regulator to the atmosphere so that the fuel injection amount can be easily adjusted even in the engine operating state where the injection time and the injection amount are not in a proportional relationship. A fuel injection amount control device for an internal combustion engine to be managed is proposed (Japanese Patent Application No. 7-8477: unpublished).

This device detects the intake pipe negative pressure or intake air amount, predicts (estimates) the pressure at the injector tip based on the detected value, and predicts (estimates) the pressure at the injector tip and the delivery pipe. Calculate the differential pressure between
The amount of fuel injection is corrected.

In a gasoline engine, for example, as shown in FIG. 13, so-called intake asynchronous injection is generally performed in which fuel is injected into the intake manifold before the intake stroke starts, that is, before the intake valve opens. . In the case of this asynchronous intake injection, the fuel injected from the injector into the intake manifold receives the heat of the inner wall of the manifold and the intake valve to promote vaporization (atomization). Further, the atomization of fuel is promoted by the high-speed airflow generated when the intake valve opens. Therefore, the combustibility of the fuel is improved in the combustion chamber.

On the other hand, when the engine is under high load,
Since the amount of fuel injected from the injector is relatively large, if asynchronous intake injection is performed, fuel that cannot be atomized will be generated before the intake stroke. This fuel that cannot be atomized adheres to the wall surface of the manifold in a liquid state. Then, since the adhered components are not supplied to the combustion chamber, the amount of fuel supplied to the combustion chamber becomes small and the air-fuel ratio tends to become lean. As a result, the combustion of fuel becomes unstable and the drivability of the engine deteriorates.

Therefore, in order to solve the above problems,
On the assumption that asynchronous intake injection is executed, a fuel injection timing control device for an internal combustion engine has been proposed which changes the injection timing so as to execute "intake synchronous injection" synchronized with the intake stroke, especially when the engine is under heavy load. (Japanese Patent Laid-Open No. 5-
23122 publication). By this intake air synchronous injection, the fuel is supplied to the combustion chamber without adhering to the manifold wall surface and the combustion stability of the fuel is secured.

That is, when the engine has a high load, the temperature in the combustion chamber becomes relatively high, so the fuel is injected into the intake manifold after the intake valve is opened. In the case of this intake-synchronized injection, the fuel taken into the combustion chamber at the same time as the injection receives the heat in the combustion chamber to promote atomization, so that the fuel burns well.

[0010]

When the technique of Japanese Patent Application No. 7-8477 described above is applied to the fuel injection timing control device as described above, the intake air synchronization performed with the intake valve open. As shown in FIG. 12, the pressure at the tip of the injector is different between the injection and the intake asynchronous injection performed with the intake valve closed, which causes a problem that the air-fuel ratio shifts. That is, in the intake synchronous injection,
As the injection timing becomes late, the injector tip pressure becomes negative, and the pressure difference between the inside of the delivery pipe becomes large, so the injection amount increases and the air-fuel ratio becomes rich at the same injection time. Note that FIG. 12 shows the pressure behavior of the injector tip, and in the figure, the dotted line indicates the prediction (estimation) of the injector tip based on the intake pipe negative pressure or the intake air amount.
Indicates pressure.

Further, when the technique of Japanese Patent Application No. 7-8477 is applied to an engine having a variable valve timing mechanism, a similar problem occurs. In an engine equipped with a variable valve timing mechanism, the variable valve timing mechanism controls the opening / closing timing of at least one of the intake valve and the exhaust valve to a low-speed timing suitable for a low engine speed region and a high-speed timing suitable for a high engine speed region. And can be selectively switched. Therefore, especially when the opening / closing timing of the intake valve is changed, the pressure at the tip of the injector changes. As a result, there is a problem that the air-fuel ratio shifts even with the same injection time.

The object of the present invention is to eliminate the above-mentioned problems of the prior art. When the injection timing or the valve timing of the intake valve is changed, the pressure at the tip of the injector during fuel injection is Even in such a case, even in such a case, the back pressure chamber of the pressure regulator is always opened to the atmosphere, and the fuel injection amount is easily managed even in the engine operating state where the injection time and the injection amount are not in a proportional relationship. It is an object of the present invention to provide a fuel injection amount control device for an internal combustion engine that can perform the operation.

[0013]

In order to solve the above problems, the invention of claim 1 is an injector provided in the intake passage, and a pressure regulator for adjusting the fuel pressure of the internal combustion engine to a certain pressure higher than atmospheric pressure. An estimating means for estimating the pressure at the injector tip in the intake passage from the engine operating state, a correction coefficient calculating means for calculating a correction coefficient from the value obtained by the estimating means, and a correction coefficient obtained by the correction coefficient calculating means The fuel injection amount control means for correcting the target fuel injection amount by the fuel injection amount control means for performing the fuel injection control with the corrected value, the injection timing changing means for changing the injection timing according to the engine operating state, and The gist is a fuel injection amount control device for an internal combustion engine, which is provided with a first correction means for correcting a correction coefficient.

According to a second aspect of the present invention, an injector provided in the intake passage, a pressure regulator for adjusting the fuel pressure of the internal combustion engine to be higher than the atmospheric pressure by a constant pressure, and the pressure at the injector tip in the intake passage is estimated from the engine operating state. Estimating means, a correction coefficient calculating means for calculating a correction coefficient from the value obtained by the estimating means, the target fuel injection amount is corrected by the correction coefficient obtained by the correction coefficient calculating means, and the corrected value is used as the fuel. A fuel injection amount control means for performing injection control, a valve timing changing means for changing valve timing of an intake valve of an internal combustion engine according to an engine operating state, and a second for correcting the correction coefficient corresponding to the valve timing. The gist of the invention is a fuel injection amount control device for an internal combustion engine including a correction means.

(Operation) According to the invention of claim 1, the pressure regulator adjusts the fuel pressure of the internal combustion engine to be higher than the atmospheric pressure by a constant pressure. The estimating means estimates the pressure at the tip of the injector in the intake passage from the engine operating state. The correction coefficient calculation means calculates a correction coefficient from the value obtained by the estimation means. The fuel injection amount control means,
The target fuel injection amount is corrected by the correction coefficient calculated by the correction coefficient calculation means, and the fuel injection control is performed with the corrected value.

Further, the injection timing changing means changes the injection timing according to the engine operating state. When the injection timing is changed, the first correcting means changes the correction coefficient corresponding to the injection timing. to correct. Therefore, the fuel injection amount control means
The target fuel injection amount is corrected with the corrected correction coefficient, and the fuel injection control is performed with the corrected value.

According to the invention of claim 2, the pressure regulator adjusts the fuel pressure of the internal combustion engine to be higher than the atmospheric pressure by a constant pressure. The estimating means estimates the pressure at the tip of the injector in the intake passage from the engine operating state. The correction coefficient calculation means calculates a correction coefficient from the value obtained by the estimation means. The fuel injection amount control means corrects the target fuel injection amount with the correction coefficient calculated by the correction coefficient calculation means, and performs the fuel injection control with the corrected value.

Further, the valve timing changing means changes the valve timing according to the engine operating state. When the valve timing is changed, the second correcting means changes the correction coefficient corresponding to the valve timing. to correct. Therefore, the fuel injection amount control means corrects the target fuel injection amount with the corrected correction coefficient, and performs the fuel injection control with the corrected value.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment in which the present invention is embodied in a naturally aspirated engine will be described below with reference to FIGS.

FIG. 1 shows a schematic configuration of a multi-cylinder gasoline engine (hereinafter, simply referred to as an engine) 1 as an internal combustion engine mounted on a vehicle and its peripheral devices. Cylinder block 1a and cylinder head 1 of engine 1
b constitutes the engine body. In the cylinder block 1a, the same number of cylinder bores 2 as the number of cylinders are arranged side by side in a direction orthogonal to the paper surface, and a piston 3 is housed in each cylinder bore 2 so as to be vertically reciprocable. The piston 3 is connected to the crankshaft 5 by a connecting rod 4. Then, the reciprocating motion of the piston 3 is converted into a rotary motion by the connecting rod 4, and the crankshaft 5 is rotationally driven.

A combustion chamber 6 is formed above the piston 3, and an intake passage 7 and an exhaust passage 8 communicate therewith.
A communication portion between the combustion chamber 6 and the intake passage 7 serves as an intake port 9, and the intake port 9 is opened and closed by an intake valve 11 attached to the cylinder head 1b so as to be vertically movable. Further, a communication portion between the combustion chamber 6 and the exhaust passage 8 is an exhaust port 10, and the exhaust port 10 is opened and closed by an exhaust valve 12 attached to the cylinder head 1b so as to be vertically movable.

An air cleaner 13, a throttle body 14, a surge tank 15, and an intake manifold 16 are arranged in this order from the upstream side toward the cylinder head 1b in the intake passage 7, and outside air is passed through the combustion chamber 6 through these components. Is taken into. A throttle valve 17 is supported by a shaft 18 in the throttle body 14 so as to be integrally rotatable. The shaft 18 is connected to an accelerator pedal (not shown) by a cable or the like. Then, when the driver depresses the accelerator pedal, the depressing operation is transmitted to the shaft 18 via a cable or the like, and the throttle valve 17 causes the shaft 1 to move.
It rotates together with 8. The rotation of the throttle valve 17 opens and closes the intake passage 7 to adjust the amount of intake air to the combustion chamber 6. The surge tank 15 is for smoothing the pulsation of intake air and preventing intake interference of each cylinder. Note that in FIG. 1, the intake manifold 16 is shown to be larger than other portions for convenience of description.

The intake manifold 16 is equipped with the same number of injectors 19 as the number of cylinders. A tip portion 19a of each injector 19 faces the intake passage 7, and fuel can be injected from the tip portion 19a toward the intake port 9 of the corresponding cylinder.

The injector 19 is connected to one delivery pipe 21. The delivery pipe 21 is connected to the fuel tank 23 by a fuel pipe 22.
The inside of both paps 21, 22 constitutes a fuel passage. A fuel pump 24 and a fuel filter 25 are interposed in the middle of the fuel pipe 22, and the fuel in the fuel tank 23 is sucked and discharged by the operation of the fuel pump 24. The fuel discharged from the fuel pump 24 is pressure-fed to the delivery pipe 21 via the fuel filter 25 and the fuel pipe 22. The pressure-fed fuel is distributed to each injector 19 by the delivery pipe 21, and is injected when the injector 19 opens.

A pressure regulator 26 is attached to the delivery pipe 21. The pressure regulator 26 holds the fuel pressure Pf that is pressure-fed to each injector 19 at a value higher than the atmospheric pressure PA by a constant pressure C.
Further, the pressure regulator 26 returns the surplus fuel (return fuel) generated by the adjustment of the fuel pressure to the fuel tank 23 through the return pipe 34.

For adjusting the fuel pressure, a diaphragm 29 having a valve body 28 is stretched in a case 27 of the pressure regulator 26 as shown in FIG. The valve body 28 and the diaphragm 29 partition the interior of the case 27 into a back pressure chamber 31 and a fuel chamber 32. The fuel chamber 32 is connected to the delivery pipe 21, from which fuel can flow into the fuel chamber 32. In addition, the case 27 has a conduit 33 for communicating the fuel chamber 32 with the outside of the case 27.
Is provided, and this conduit 33 is connected to the fuel tank 23 by a return pipe. Then, the fuel in the fuel chamber 32 can be led out to the fuel tank 23 through the conduit 33 and the return pipe 34.

On the other hand, a coil spring 35 is arranged in a compressed state in the back pressure chamber 31, and the coil spring 35 constantly urges the valve body 28 in the direction of closing the conduit 33. The back pressure chamber 31 is open to the atmosphere, and the inside of the back pressure chamber 31 is always at atmospheric pressure.

A mixture of fuel injected from each injector 19 and outside air introduced into the intake passage 7 is introduced into the combustion chamber 6 through the intake port 9 when the intake valve 11 is opened. In order to ignite the air-fuel mixture introduced into the combustion chamber 6, a semiconductor ignition type ignition device is provided. This ignition device includes an ignition coil 38 and an igniter 39 that generate a high voltage by utilizing a transient phenomenon of an electric circuit, a distributor 41 that distributes the high voltage to each cylinder, and an ignition plug 42 that is a discharge unit. Has been done.

Then, the air-fuel mixture introduced into the combustion chamber 6 is burned by the ignition of the spark plug 42, and the piston 3,
The driving force of the engine 1 can be obtained via the connecting rod 4, the crankshaft 5, and the like. The burned gas (exhaust gas) burned in the combustion chamber 6 is led out from the exhaust port 10 to the exhaust passage 8 when the exhaust valve 12 is opened.

An exhaust manifold 43 and a catalytic converter 44 are disposed in the exhaust passage 8 from the cylinder head 1b toward the downstream side, and exhaust gas is exhausted to the outside through these.

In order to detect the operating state of the engine 1, an air flow meter 46, an intake air temperature sensor 47, a throttle sensor 48, a water temperature sensor 49, an oxygen sensor 50,
A rotation speed sensor 51, a cylinder discrimination sensor 52, etc. are provided. The air flow meter 46 is an intake air amount detecting means for measuring an intake air amount taken by the engine 1. In the present embodiment, the measuring plate (vane) is pushed open by a pressure difference generated when the intake air passes. Type is used. The intake air temperature sensor 47 is installed in the air flow meter, and detects a temperature change (intake air temperature THA) of the intake air flowing through the intake passage 7 by a change in the resistance value of the built-in thermistor. Intake air temperature THA
Corresponds to the ambient temperature around the tip portion 19a of the injector 19.

The throttle sensor 48 is attached to the throttle body 14 and detects the opening of the throttle valve 17 (throttle opening). The water temperature sensor 49 is attached to the water outlet and detects the temperature of the cooling water of the engine 1 (cooling water temperature THW). More specifically, like the intake air temperature sensor 47, the water temperature sensor 49 is composed of a thermistor whose resistance value greatly changes with temperature, and detects a change in the cooling water temperature THW by a change in resistance value. Cooling water temperature TH
W corresponds to the temperature of the cylinder block 1a and the cylinder head 1b.

The oxygen sensor 50 is attached to the exhaust manifold 43 and detects the oxygen concentration in the exhaust gas. Both the rotation speed sensor 51 and the cylinder discrimination sensor 52 are built in the distributor 41. Rotation speed sensor 51
Is composed of one timing rotor having a large number (for example, 24) of protrusions on the outer circumference and one pickup coil. In this rotation speed sensor 51, when the timing rotor makes one rotation, the pickup coil outputs the same number of pulse signals as the projections at an equal crank angle (for example, 30 rpm).
°) every time. The cylinder discrimination sensor 52 is composed of one timing rotor having one protrusion on the outer periphery and two pickup coils. In this cylinder discrimination sensor 52, when the timing rotor makes one revolution,
Each pickup coil alternately generates one pulse signal at every crank angle of 360 °.

The air flow meter 46 and various sensors 4
7 to 52 are electrically connected to the input side of an electronic control unit (hereinafter referred to as ECU) 53. The injectors 19 and the igniter 39 are electrically connected to the output side of the ECU 53.

As shown in FIG. 4, the ECU 53 includes a central processing unit (hereinafter, CPU) 54, a read-only memory (hereinafter, ROM) 55, a random access memory (hereinafter, RAM) 56, and a backup RAM 5.
7, an external input circuit 58, and an external output circuit 59, which are connected to each other by a bus 60. CPU5
Reference numeral 4 executes various arithmetic processes according to a preset control program. The CPU 54 constitutes an estimating means, a correction coefficient calculating means, an injection timing changing means, a first correcting means and a fuel injection amount control means. ROM 55 is CP
The control program and initial data necessary for executing the arithmetic processing in U54 are stored in advance. The ROM 55 constitutes intake air amount storage means. RAM5
6 temporarily stores the calculation result of the CPU 54, and backs up R
The AM 57 is backed up by a battery so as to retain various data even after the power is turned off. The external input circuit 58 has an A / D converter (analog / digital converter) and converts analog signals such as an intake air temperature signal from the intake air temperature sensor 47 and a cooling water temperature signal from the water temperature sensor 49 into a digital signal.

Various signals from the air flow meter 46, the intake air temperature sensor 47, the throttle sensor 48, the water temperature sensor 49, the oxygen sensor 50, the rotation speed sensor 51 and the cylinder discrimination sensor 52 are input to an external input circuit 58. CPU
Reference numeral 54 represents the intake air amount GA, intake air temperature THA, throttle opening, cooling water temperature THW, oxygen concentration, based on these signals.
The engine speed NE, the cylinder discrimination signal, etc. are detected.

The CPU 54 also controls the igniter 39 via the external output circuit 59. That is, the optimal ignition timing corresponding to the operating state of the engine 1 is stored in the ROM 55 in advance, and the CPU 54 detects the operating state of the engine 1 by the signals from the various sensors including the rotation speed sensor 51, and the optimal ignition is performed. Calculate the time. And CPU5
Reference numeral 4 outputs an ignition instruction signal to the igniter 39 via the external output circuit 59 to control the ignition timing.

Next, the operation and effect of the embodiment configured as described above will be described. The flowchart of FIG. 5 shows a routine for calculating the correction coefficient KFPC among the processes executed by the CPU 54. Further, FIG. 7 shows a target injection end timing executed by the CPU 54,
The fuel injection timing calculation routine for calculating target fuel injection time TAU etc. is shown. All of these routines are executed at a predetermined timing. Also, FIG. 11 (a)
And (b) show an injection interrupt routine and an injection end interrupt routine.

When the correction coefficient calculation routine of FIG. 5 is started, the CPU 54 first makes a step (hereinafter referred to as S) 10
1, the air flow meter 46 detects
Intake air amount G converted to digital signal by the / D converter
Read A. Further, in the same step, the engine speed NE detected by the speed sensor 51 is read and subsequently GN = GA / NE is obtained. Next, in S102, the air amount GNMAX per unit rotation (one rotation) is calculated. The air amount GNMAX per unit rotation is a standard intake air amount per unit rotation when the throttle valve is fully opened at any engine speed NE, and is obtained in advance by tests, etc. under standard atmospheric pressure and standard intake air temperature. Has been
It is stored in the ROM 55 as map data. Therefore, the air amount GNMAX per unit rotation is obtained by referring to this map data based on the engine speed NE obtained in S101.

Next, the CPU 54 calculates the estimated intake pipe pressure P1 in the following equation in S103. P1 = GN / GNMAX (2) By the way, the ratio of GN and GNMAX has a strong correlation with the pressure near the nozzle of the injector 19 (the nozzle pressure), and when GN / GNMAX = 0, it is a vacuum. , GN /
When GNMAX = 1, it can be considered as atmospheric pressure.

Therefore, the tip pressure of the injector 19 (pressure near the injection port) is estimated by GN / GNMAX. The GN corresponds to the engine operating state for estimating the tip pressure of the injector 19.

Next, the CPU 54 calculates the correction coefficient KFPC in S104 with reference to the map data shown in FIG. Explaining this map data, the map data is a two-dimensional map of the correction coefficient KFPC and the estimated intake pipe pressure P1, and the following relationship is established between them.

KFPC = (C / (C + PA-P1)) ^1/2 (3) where C is the set fuel pressure. PA is atmospheric pressure. Then, a map of the correction coefficient KFPC with respect to the estimated intake pipe pressure P1 is created in advance based on the equation (3), and the ROM 5
Stored in 5. The above formula (3) will be described.

FIG. 6 is a schematic diagram showing the relationship between the intake port pressure and the delivery fuel pressure Pf. PM indicates the intake port pressure (= surge tank pressure). Straight line Pf = PM +
C indicates the case of controlling the conventional fuel pressure, and the straight line Pf = PA
+ C indicates the case where the fuel pressure is controlled to be constant in the present embodiment. A is Pf = PA + C and P in this embodiment.
Shows the difference with M, and B shows the difference between Pf = PM + C and PM (=
C).

Since it is known that the injection amount of the injector 16 is proportional to the square root of these differential pressures,
The fuel injection amount is the target injection time TAU × correction coefficient (B /
A) obtained by ^1/2. Further, from FIG. 6, A = (PA + C) −PM B = C. Then, when the estimated intake pipe pressure P1 is substituted for the intake port pressure PM, the correction coefficient (B / A) ^1/2 becomes the equation (3).

As described above, the CPU 54 calculates the correction coefficient KFPC in S104, and the calculated result is temporarily RA.
After storing in the predetermined address of M56, this routine is exited.

Next, when the routine for calculating the fuel injection timing shown in FIG. 7 is entered, in S210, the engine speed NE,
The intake air amount GN per revolution is calculated based on the intake air amount GA, and the injection end timing is calculated from the table shown in FIG. 8 based on the engine speed NE and the intake air amount GN per revolution. To do. This table is stored in the ROM 55. The injection end timing of this table is obtained in advance by a test or the like, and the engine speed N
It is set to the most suitable value when E and the intake air amount GN per rotation speed are changed. In FIG. 8, the value of each injection end timing is the value of ATDC (crank angle from top dead center).

Next, in S220, the target fuel injection time TAU corresponding to the fuel injection amount is calculated. That is, C
The PU 54 uses the injector 1 so that the air-fuel ratio (air / fuel weight ratio in the air-fuel mixture sucked into the engine 1) A / F detected by the output signal of the oxygen sensor 50 becomes the stoichiometric air-fuel ratio.
The fuel injection amount from 9 is adjusted. In order to adjust the fuel injection amount, the CPU 54 calculates the target fuel injection time TAU which is the valve opening time of the injector 19 based on the following equation (4).

TAU = K × (GA / NE) × (K1 + K2 + ...) (4) Here, K is an injection amount-injection time conversion coefficient depending on the injector size, GA is the intake air amount, and NE is the It is the engine speed, and K · (GA / NE) is the basic injection time set to obtain the stoichiometric air-fuel ratio. That is,
It is the injection time when the difference between the injector tip pressure and the delivery pipe pressure is constant. Further, K1, K2, etc. are various correction coefficients, and include, for example, those related to intake air temperature, warm-up increase, post-start increase, air-fuel ratio feedback control, and the like. The coefficient relating to the intake air temperature is for correcting the deviation due to the intake air temperature THA, and is obtained based on the intake air temperature THA.
The coefficient relating to the warm-up increase amount is for increasing the basic injection time for improving the operation control during cold, and is obtained based on the cooling water temperature THW. The coefficient related to the post-start increase is to stabilize the engine speed NE immediately after the engine is started, and is obtained based on the cooling water temperature THW.

The coefficient relating to the increase in output is for prolonging the basic injection time when the catalytic converter provided in the engine 1 or the exhaust passage 7 is easily heated. With this correction, the drivability of the engine 1 under high load is improved,
The rise in catalyst temperature is suppressed. The coefficient relating to the feedback control of the air-fuel ratio is for correcting the basic injection time so that the air-fuel ratio of the air-fuel mixture becomes the stoichiometric air-fuel ratio. The stoichiometric air-fuel ratio is the air-fuel ratio of the air-fuel mixture containing just enough oxygen to completely oxidize the fuel. For the correction, the CPU 54 uses the signal of the oxygen sensor 50 to make the air-fuel ratio richer or leaner than the theoretical air-fuel ratio.
Judge. The CPU 54 shortens the basic injection time when rich, and lengthens the basic injection time when lean.

Subsequently, in S230, the injection end timing calculated in S210 and S220 and the basic injection time T
The injection start timing t1 is calculated based on AU. Next, S2
40, the calculated injection start timing t1 is the CPU 5
It is determined whether the processing delay time of 4 has already passed. If it has already passed (NO), in S270, the injection start timing t1 is closest to the injection disclosure timing kt1.
And set it again. Note that k is a coefficient. Also, S24
If 0 has not passed (YES), S250
Move to

In S250, t calculated in S230
It is determined whether or not the difference between the injection start timing t1 reset at 1 or S270 and the previous cylinder injection time is less than or equal to the determination value Kangle. This determination value Kangle is for a guard that prevents sudden changes in the injection timing. That is, if the difference between the injection start timing t1 and the previous cylinder injection timing is the determination value Kangl.
If e is exceeded, if fuel injection is performed at this injection disclosure timing t1, the injection start timing of the injector to be controlled for this cylinder is too late compared to the previous cylinder injection timing, and as a result, drivability deteriorates. To guard against this. In S250, if the difference between t1 and the previous cylinder injection exceeds the determination value Kangle, S28
At 0, the injection timing t1 is reset to kt2, and S
Move to 260. This kt2 is obtained by converting the judgment value Kangle into time.

If the difference between t1 and the previous cylinder injection is equal to or smaller than the determination value Kangle in S250, S260.
Move to In S260, the injection interruption is t1.
, And this processing routine is ended.

Next, the injection interruption routine is shown in FIG.
A description will be given according to (a). This processing routine is interrupted at the injection timing t1. When entering this process,
In S310, current time (t1) + T of TAU / 2
Calculate ang (crank angle). Next, S320
In, the correction amount P of the correction coefficient KFPC is calculated based on the crank angle Tang with reference to the table shown in FIG. 9 or the map shown in FIG. The table and map are stored in the ROM 55. When the crank angle Tang increases from 0 ° CA to 240 ° CA, the table and the map show a correction amount P.
Is designed to be large. That is, from the point where the crank angle Tang exceeds 0 ° CA, 240 ° C
In the case of A, since the intake-synchronized injection is performed, the tip pressure of the injector 19 becomes negative as the injection timing is delayed, and the pressure difference between the inside of the delivery pipe and the injector becomes large. Therefore, the correction amount P is set so that the injection amount does not increase in the same injection time.

Further, when the crank angle Tang is before 0 ° CA, the intake asynchronous injection is performed, and therefore the tip pressure of the injector 19 is substantially equal to the predicted (estimated) pressure, and therefore the correction is performed. The quantity is zero. The correction amount P is obtained in advance by a test or the like. In S310 and S320, TAU / 2 is used because the tip pressure of the injector 19 is the injector 1
It can be considered that the middle of the time TAU in which 9 is injecting is an average, and therefore, the correction of the correction coefficient KFPC is most appropriate at the Tang (crank angle) calculated in S310. is there.

Next, in S330, the CPU 54 RA
The final fuel is read by reading the correction coefficient KFPC stored in M56, subtracting the correction coefficient KFPC by the correction amount P, and multiplying the subtraction result by the target fuel injection time TAU calculated in step 220. Calculate the injection time. That is, the final fuel injection time is calculated based on the following formula.

Final fuel injection time = TAU × KFPC (1-P) Then, in S340, injection is started. That is, the CPU 54 outputs the drive signal to the injector 19 via the external output circuit 59. Then, by the output of this signal, the injector 19 injects fuel. In this S340, the crank angle Tang is 0 ° C.
In the case of A to 240 ° CA, intake synchronous injection is performed. Further, when the crank angle Tang is before 0 ° CA, the intake asynchronous injection is performed. Then, CPU
In S350, 54 sets the injection end timer included in the CPU 54 and exits this processing routine.

Next, when the injection end timing is reached, the CPU 54 interrupts the injection end interrupt routine of FIG. 11B based on the timer count of the injection end timer.

When this processing is entered, the injection is ended in S410. That is, the CPU 54 outputs this drive stop signal to the injector 19 via the external output circuit 59. The output of this signal causes the injector 19
Is closed. (A) According to the present embodiment, the fuel injection timing is set in the fuel injection timing calculation routine shown in FIG. 7, whereby the intake asynchronous injection or the intake synchronous injection is performed depending on the operating state of the engine 1. Done.

When the intake asynchronous injection is performed, the tip pressure of the injector 19 substantially matches the predicted (estimated) pressure, so the correction amount P is set to zero.
As a result, the correction coefficient KFPC is not corrected but is multiplied by the target fuel injection time TAU to calculate the final fuel injection time.

As described above, in the present embodiment, the back pressure chamber 31 of the pressure regulator 26 is always kept at the atmospheric pressure, so that the switching valve for correcting the atmospheric pressure becomes unnecessary,
The system is simplified. Further, by releasing the back pressure of the pressure regulator 26 to the atmospheric pressure, even if the relationship between the conventional injection time and the injection amount is changed, the pressure correction can be easily handled by the control program software, thereby controlling the pressure. Of deterioration is prevented.

(B) When the intake-synchronized injection is performed, the tip pressure of the injector 19 does not match the predicted (estimated) pressure, so the correction amount P corresponding to the crank angle Tang is calculated. Then, the correction coefficient KFPC
Is calculated by multiplying the target fuel injection time TAU by the value corrected by the correction amount P. As a result, the injector tip pressure becomes negative as the injection timing becomes late, and the pressure difference between the inside of the delivery pipe and the injection pipe becomes large. However, in this embodiment, the correction coefficient KFP is set at the correction amount P corresponding to the crank angle Tang.
Since C is corrected so that the final fuel injection time, that is, the fuel injection amount is not increased, the air-fuel ratio does not shift. (Second Embodiment) Next, the second embodiment will be described with reference to FIG.
It will be described with reference to FIGS. Only points different from the first embodiment will be described.

In this embodiment, instead of the air flow meter 46 of the first embodiment, the surge tank 15 has a pressure (intake pipe pressure (= surge) in the surge tank 15 based on vacuum). (Tank pressure), for convenience of explanation, it may be referred to as intake pressure in this embodiment) PM
A semiconductor type intake pressure sensor 69 for detecting is attached. The intake pressure sensor 45 constitutes an intake pressure detecting means. Further, a semiconductor-type atmospheric pressure sensor 44 for detecting the atmospheric pressure (absolute pressure) PA is provided in the vehicle compartment. The atmospheric pressure sensor 44 constitutes an atmospheric pressure detecting means.

The intake pressure signal and the atmospheric pressure signal from both sensors 68 and 69 are input to the external input circuit 58, respectively.
The CPU 54, based on both signals, intake pressure PM, atmospheric pressure PA
Is detected. The CPU 54 constitutes a corrected intake pressure calculation means.

Further, in this embodiment, the correction coefficient KFP
The C calculation routine and the fuel injection timing calculation routine are different from those in the first embodiment. FIG. 16 shows a correction coefficient calculation routine of this embodiment.

When this correction coefficient calculation routine is started, the CPU 54 first detects the atmospheric pressure PA detected by the atmospheric pressure sensor 44 and the intake pressure sensor 45 in S501 and converted into a digital signal by the A / D converter. And intake pressure P
Read M. Next, in S502, "1-atmospheric pressure PA" is added to the intake pressure PM to obtain a PM correction value (corrected surge tank pressure). The reason for adding "1-atmospheric pressure PA" to this intake pressure PM is as follows.

FIG. 15 is a schematic diagram showing the relationship between the intake fuel pressure (= surge tank pressure) and the delivery fuel pressure Pf. In the figure, the solid line Pf = PM + C shows the case where the conventional fuel pressure is controlled, and the solid line Pf = PA + C shows the case where the fuel pressure is constantly controlled in the first embodiment. A indicates the difference between Pf = PA + C and PM in the first embodiment, and B indicates the difference (= C) between Pf = PM + C and PM.

Further, in the figure, the chain line Pf = PM1 + C
Shows the case where the conventional fuel pressure is controlled when the atmospheric pressure is low, and the chain line Pf = PA1 + C shows the case where the fuel pressure is controlled to be constant at the low pressure in the present embodiment. A1 indicates the difference between Pf = PA1 + C and PM1, and B1
1 is the difference (= C) between Pf = PM1 + C and PM1.

As described in the first embodiment, it is known that the injection amount of the injector 16 is proportional to (B / A) ^1/2 , so the fuel injection amount is the target fuel injection time TAU × It is obtained by the correction coefficient (B / A) ^1/2 . However, as described above, when the atmospheric pressure is low, the injection amount of the injector 16 is proportional to (B1 / A1) ^1/2 , so when the atmospheric pressure is low, the correction coefficient (B /
A) ^1/2 will be misaligned. Therefore, in the present embodiment, the actual atmospheric pressure is reflected in S502 to eliminate this deviation. S502 constitutes a corrected intake pressure calculation means.

After the processing of S502, the CPU 54 executes S503.
Then, the correction coefficient KFPC is calculated. S503
The calculation formula of the correction coefficient KFPC in is the following formula. KFPC = (C / (C + PA-PM)) ^{1/2 In} the first embodiment, the correction coefficient KFPC is calculated by the equation (3) in S104, which uses the estimated intake pipe pressure P1. This is because In this embodiment, in S503, the PM correction value (corrected surge tank pressure) calculated in S502 is used instead of the estimated intake pipe pressure P1.

When the CPU 54 has processed S503, it exits this routine. Further, in the fuel injection timing calculation routine in this embodiment, as shown in FIG. 17, among the steps of the fuel injection timing calculation routine of FIG. 7 in the first embodiment, S210 becomes S211, S220 becomes S221. What is done is different. Explaining these different steps, S21
In 1, the injection end timing is calculated from the control map based on the engine speed NE and the intake pressure PM. This map is stored in the ROM 55. The injection end timing of this map is obtained in advance by a test or the like, and is set to the most suitable value when the engine speed NE and the intake pressure PM are changed. Next, in S221, the target fuel injection time TAU corresponding to the fuel injection amount is calculated. That is, the CPU 54 controls the fuel from the injector 19 so that the air-fuel ratio (air / fuel weight ratio in the air-fuel mixture sucked into the engine 1) A / F detected by the output signal of the oxygen sensor 50 becomes the stoichiometric air-fuel ratio. Adjust the injection amount. In order to adjust the fuel injection amount, the CPU 54 calculates the target fuel injection time TAU which is the valve opening time of the injector 19 based on the following equation (4).

TAU = K × Q × (K1 + K2 + ...) (4) Here, K is a conversion coefficient of the injection amount by the injector size-injection time, Q is the converted intake air amount corresponding to the intake pressure PM, K · Q is the basic injection time set to obtain the stoichiometric air-fuel ratio. That is, the injection time when the injector tip pressure-the pressure difference in the delivery pipe is constant.

The subsequent processing is performed in the same manner as in the first embodiment, so that the injection interrupt t1 is set. Therefore, in this embodiment, in addition to the operational effects of (a) and (b) of the first embodiment, the correction coefficient KFPC is obtained from the intake pressure PM reflecting the atmospheric pressure PA, and the correction coefficient KFPC is obtained. Since KFPC is used to calculate the final fuel injection time, it is possible to perform appropriate air-fuel ratio control even if the atmospheric pressure changes. (Third Embodiment) Next, the third embodiment will be described with reference to FIG.
23 to 23. In addition, in the configuration of the second embodiment, the same configuration or the corresponding configuration will be denoted by the same reference numerals and the description thereof will be omitted, and different points will be mainly described.

Above the intake valve 11, the intake valve 1
An intake-side camshaft 61 for driving the opening / closing 1 is arranged, and an exhaust-side camshaft 62 for driving the opening / closing the exhaust valve 12 is arranged above the exhaust valve 12. An intake side timing pulley 63 and an exhaust side timing pulley 64 are provided at one end of each camshaft 61, 62.
The timing pulleys 63, 64 are connected to the crankshaft 5 via a timing belt 65.

Therefore, when the engine 1 is operating, the rotational driving force is transmitted from the crankshaft 5 to the camshafts 61 and 62 through the timing belt 65 and the timing pulleys 63 and 64, and the camshafts 61 and 62 rotate. The intake valve 11 and the exhaust valve 12 are opened and closed.

In the gasoline engine system according to the present embodiment, the variable valve timing mechanism 66 (hereinafter referred to as "variable valve timing mechanism 66" driven by hydraulic pressure on the intake side timing pulley 63 is used in order to realize the valve overlap by changing the opening / closing timing of the intake valve 11. VVT ”) is provided. The configuration of this VVT 66 will be described with reference to FIG. FIG. 19 is a cross-sectional view of the vicinity of the intake side camshaft 61 showing a schematic configuration diagram of the VVT 66.

The VVT 66 is provided with a housing 67 integrally provided with the timing pulley 63 at the tip of the intake side camshaft 61. And the housing 67
The tip of the intake side camshaft 61 is incorporated inside, and helical teeth are formed on the inner peripheral surface of the housing 67. In addition, on the end surface of the intake side camshaft 61,
A cylindrical gear 68 is fixed by a hollow bolt 69. Further, between the housing 67 and the gear 68,
A ring gear 70 that connects the two is interposed. Helical teeth are formed on the inner and outer peripheral surfaces of the ring gear 70 and mesh with the helical teeth of the housing 67 and the gear 68, respectively, and inside the housing 67, the axial direction of the intake side camshaft 61 (left and right in FIG. 19). Direction)).

When the housing 67 is driven to rotate integrally with the intake side timing pulley 63, the cam shaft 61 is driven to rotate integrally with the intake side timing pulley 63 via the ring gear 70. Further, by moving the ring gear 70 in the axial direction to change the arrangement, the relative positions of the intake side timing pulley 63 and the intake side cam shaft 61 in the rotational direction are changed.

In order to move the ring gear 70 in the axial direction, two hydraulic chambers 71 and 72 are formed at both ends of the ring gear 70 inside the housing 67, and the intake side camshaft is formed in each hydraulic chamber 71 and 72. Two systems of hydraulic pressure supply passages 73 and 74 formed in 61 etc. are connected.
Then, the lubricating oil sucked up from the oil pan 76 by the hydraulic pump 75 is supplied to the respective hydraulic chambers 71, 72 at a predetermined pressure via the oil filter 77.

Further, each hydraulic chamber 7 adjacent to the ring gear 70
A linear solenoid valve (LSV) 78 is arranged in each hydraulic pressure supply passage 73, 74 between the VVT 66, the oil pan 76, and the oil filter 77 in order to selectively supply hydraulic pressure to the motors 1, 72. This LSV78
Is an electromagnetic four-way valve, the opening degree of which is adjusted by duty control.

In the VVT 66 having these configurations, L
The SV 78 is drive-controlled and hydraulic pressure is applied to one end of the ring gear 70 on the hydraulic chamber 71 side, whereby the ring gear 70 rotates while moving in one direction and rotates.
A twist is added to 1. As a result, the relative position of the camshaft 61 and the intake side timing pulley 63 in the rotation direction is changed, and the opening / closing timing of the intake valve 11 is advanced. Therefore, the intake valve 11 is replaced by the exhaust valve 12
The valve overlaps while the intake valve 11 is open and the intake valve 11 and the exhaust valve 12 are simultaneously opened.

On the other hand, when the LSV 78 is drive-controlled and the hydraulic pressure is applied to the other end of the ring gear 70 on the hydraulic chamber 72 side, the ring gear 70 rotates while moving in the opposite direction to the cam shaft 61 in the opposite direction. Is given a twist. As a result, the opening / closing timing of the intake valve 11 is retarded and valve overlap does not occur.

Further, in this embodiment, the cylinder head 1b is provided with a cam angle sensor 79. The cam angle sensor 79 includes a rotor mounted on the intake-side camshaft 61 so as to be integrally rotatable, and an electromagnetic pickup arranged in the vicinity of the rotor so as to face each other. The rotor is made of a disk-shaped magnetic body and has a plurality of teeth on its outer circumference.
The electromagnetic pickup accompanies the rotation of the crankshaft 5.
Each time the rotor rotates and the teeth pass in front of the electromagnetic pickup, a pulsed cam angle signal SG2 is output. The cam angle sensor 79 has an external input circuit 5 for the CPU 54.
8 are connected. On the other hand, the LSV 78 is connected to the external output circuit 59.

The CPU 54 calculates the engine speed NE, the displacement angle θ, etc. based on the sensors 45, 47 to 52, 79 input via the external input circuit 59. And C
The PU 54 determines each injector 1 based on these calculated values.
9, the operation of the igniter 39 and the LSV 78 is controlled, and fuel injection amount control, ignition timing control, valve timing control, etc. are executed.

For example, the CPU 54 uses the rotation speed sensor 51.
The engine rotational speed NE is calculated by measuring the generation interval (time) of the rotational speed signal SG1 output by the engine. CPU
54 is a rotation speed signal SG1 when the cam angle signal SG2 is generated.
And the rotational phase (displacement angle θ) of the camshaft 61 based on the preset rotational speed signal. This displacement angle θ
Is V for adjusting the opening / closing timing of the intake valve 11.
This corresponds to the operation timing of the intake side camshaft 61 changed by the VT 66.

In order to control the ignition timing, the ROM 55 has
The optimum ignition timing according to the operating state of the engine 1 is stored in advance. The CPU 54 uses the detection signals of the respective sensors to detect the operating state of the engine 1 (engine speed, intake pressure,
The warm-up state etc. is detected, the optimum ignition timing is calculated with reference to the data in the ROM 55, and a primary current cutoff signal is output to the igniter 39 to control the ignition timing.

Also, for valve timing control, CP
U54 is a throttle sensor 4 for detecting the engine operating state.
8, the throttle opening TA by the rotation speed sensor 51, the cam angle sensor 79, etc., the engine rotation speed NE, the displacement angle θ, etc. are read. The CPU 54 uses the control map prepared in advance, and uses the throttle opening TA and the engine speed N.
The target displacement angle θVTA is calculated based on E and the like. And
The CPU 54 feedback-controls the opening degree of the LSV 78 so that the displacement angle θ matches the target displacement angle θVTA. By this control, both hydraulic chambers 71, 72 of the VVT 66 are
The hydraulic pressure supplied to is adjusted. And the intake valve 1
The opening / closing timing of No. 1 is continuously changed according to the operating state of the engine 1, so that the valve overlap is continuously adjusted. By adjusting the valve overlap, the intake charge efficiency in the combustion chamber 6 is increased as necessary. Therefore, in this embodiment, the CPU 54 constitutes a valve timing changing means.

Now, the gasoline engine system configured as described above differs from the second embodiment in that the VVT 66 is controlled.
The control of the VVT 66 and the intake asynchronous injection and intake synchronous injection control will be described with reference to the time chart of FIG.

Here, in FIG. 21, V for advancing the valve opening timing of the intake valve 11 to lengthen the valve overlap period.
In the engine 1 equipped with the VT66, the intake valve 11
3 is a time chart showing the valve opening timing of the exhaust valve 12 and the timing relationship when performing the intake asynchronous injection control and the intake synchronous injection control for fuel injection.

As shown in FIG. 21, the period in which the intake synchronous injection is performed and the variable range (period) of the opening timing of the intake valve 11 by the VVT 66 may or may not overlap depending on the displacement angle θ. Can be. That is, VV
In the variable range of T66, the intake valve 11 may open earlier than the start of intake synchronous injection due to the change of the valve opening timing of the intake valve 11. Therefore,
In such a case, the timing of the pressure change at the tip of the injector 19 is moved to the advance side as compared with the second embodiment. Therefore, in this embodiment, the injection interrupt routine of FIG. 11A is different from that of the second embodiment so that the air-fuel ratio does not shift even if the injection time is the same.

That is, in this embodiment, the above-mentioned FIG.
In S320 of 1 (a), the crank angle Tan
Based on g, the table shown in FIG. 9 or the table shown in FIG. 22 instead of the map shown in FIG.
The FPC correction amount P is calculated. This table is R
It is stored in the OM55. The correction amount P is obtained in advance by a test or the like. The table is 24 from where the crank angle Tang exceeds 0 ° CA.
When it increases to 0 ° CA, the correction amount P increases at each displacement angle θ.

That is, as the opening timing of the intake valve 11 is displaced toward the advance side, the valve overlap amount becomes larger, that is, the exhaust valve 12 is opened and the piston 3 in the exhaust stroke is being raised. is there. Therefore, the tip pressure of the injector 19 in the intake passage 7 is not so large in negative pressure as compared with the case where the displacement angle is 0 ° CA.

From this, when the displacement angle θ is 0 ° CA, it is the same as the table of FIG. 9, and when the displacement angle θ is 30 ° CA, the opening timing of the intake valve 11 is set. Is advanced, the correction amount P is smaller than that when the displacement angle θ is 0 ° CA. Similarly, when the displacement angle θ is 60 ° CA, the opening timing of the intake valve 11 is advanced more than when the displacement angle θ is 30 ° CA. Therefore, when the displacement angle θ is 0 ° CA The correction amount P is further smaller than that of

Therefore, in this embodiment, the CP
U54 constitutes a second correction means. In the present embodiment, in addition to the effects of the second embodiment, in the gasoline engine system including the VVT 66, when the opening timing of the intake valve 11 is changed due to the control of the VVT 66. Also, the correction coefficient KFPC can be corrected corresponding to the displacement angle θ.

The present invention may be embodied as follows. (A) In step 602 of the second embodiment, the value obtained by adding "1-atmospheric pressure PA" to the intake pressure PM is PM.
The correction value (corrected surge tank pressure) was used, but instead, the PM correction value (corrected surge tank pressure) was used as "intake pressure PM.
The calculated value of "/ atmospheric pressure PA" may be used.

(B) In each of the above embodiments, the pressure regulator 26 is embodied as a type that returns excess fuel, but it is embodied as a type that arranges a pressure regulator in the fuel tank and makes a return in the tank. May be.

(C) In the third embodiment, the intake pressure sensor 45 and the atmospheric pressure sensor 44 may be omitted, and instead, an air flow meter may be provided as in the first embodiment.

From the matters described in this specification, the technical idea grasped other than the claims described in the scope of claims will be described together with their effects. (1) An injector provided in the intake passage, a pressure regulator for adjusting the fuel pressure of the internal combustion engine to be higher than the atmospheric pressure by a constant pressure, an intake pressure detecting means for detecting the intake pressure of the engine, and the intake pressure and the atmospheric pressure. A corrected intake pressure calculation means for calculating a corrected intake pressure calculated from the above, a calculation means for calculating a correction coefficient for constant fuel pressure control based on the value calculated by the corrected intake pressure calculation means, and the calculation means And a valve timing for changing the valve timing of the intake valve of the internal combustion engine in accordance with the engine operating state by correcting the fuel injection amount based on the correction coefficient value and controlling the fuel injection amount with the corrected value. A fuel injection amount control device for an internal combustion engine, comprising: a changing unit; and a second correcting unit that corrects the correction coefficient according to the valve timing. By doing this, the correction coefficient KFPC is obtained from the intake pressure PM that reflects the atmospheric pressure PA, and this correction coefficient KFPC is used to calculate the final fuel injection time. Therefore, it is appropriate even if the atmospheric pressure changes. Air-fuel ratio control can be performed.

[0099]

As described above in detail, according to the inventions of claims 1 and 2, the back pressure chamber of the pressure regulator is always open to the atmosphere, and the injection time and the injection amount are not in a proportional relationship. Even in the operating state, the fuel injection amount can be easily managed. Therefore, a switching valve for performing atmospheric pressure correction is unnecessary, and the system can be simplified. Also, by opening the back pressure of the pressure regulator to atmospheric pressure, even if the relationship between the injection time and the injection amount is changed, pressure correction can be easily handled with the control program software, preventing control deterioration. can do.

Further, when the injection timing or the valve timing of the intake valve is changed, the pressure at the tip of the injector changes during fuel injection. Even in such a case, the back pressure chamber of the pressure regulator is always opened to the atmosphere. However, the fuel injection amount can be easily managed even in an engine operating state in which the injection time and the injection amount do not have a proportional relationship.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine and its peripheral devices according to a first embodiment.

FIG. 2 is a sectional view of the pressure regulator of the same embodiment.

FIG. 3 is an explanatory diagram of a map of a correction coefficient KFPC and an estimated intake pipe pressure P1.

FIG. 4 is a block diagram showing an electrical configuration of an ECU.

FIG. 5 is a flowchart of a KFPC calculation routine.

FIG. 6 is a schematic diagram showing the relationship between the intake port pressure and the delivery fuel pressure Pf.

FIG. 7 is a flowchart of a fuel injection timing calculation routine.

FIG. 8 is an explanatory diagram showing a table of an engine speed NE and an intake air amount GN per unit speed.

FIG. 9 is an explanatory diagram showing a table of a correction amount P at a crank angle at TAU / 2.

FIG. 10 is an explanatory diagram showing a map with a correction amount P at a crank angle at TAU / 2.

11 (a) and (b) are injection interrupt routines,
And a flowchart of an injection end interrupt routine.

FIG. 12 is a time chart of intake valve lift and injector tip pressure.

FIG. 13 is a time chart of intake valve lift and injection timing.

FIG. 14 is a schematic configuration diagram of an engine and its peripheral devices according to a second embodiment.

FIG. 15 is a schematic diagram showing the relationship between the intake fuel pressure (= surge tank pressure) and the delivery fuel pressure Pf.

FIG. 16 is a flowchart of a KFPC calculation routine.

FIG. 17 is a flowchart of a fuel injection timing calculation routine.

FIG. 18 is a schematic configuration diagram of an engine and its peripheral devices according to a third embodiment.

FIG. 19 is a sectional view of the VVT.

FIG. 20 is a block diagram showing the electrical configuration of the ECU.

FIG. 21 is a time chart showing the relationship between the valve opening timing of the intake valve and the exhaust valve and the fuel injection timing.

FIG. 22 is an explanatory view showing a table of the correction amount P at the crank angle at TAU / 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 15 ... Surge tank, 17 ... Throttle valve, 19 ... Injector, 26 ... Pressure regulator, 46 ... Air flow meter which comprises an intake air amount detection means, 53 ... Electronic control unit (ECU), 54 ... Estimating means , Central processing unit (CPU) constituting the correction coefficient calculation means, fuel injection amount control means, first and second correction means, injection timing changing means, valve timing changing means, 55 ... R
OM.

Claims (2)

[Claims] 1. An injector provided in an intake passage, a pressure regulator for adjusting a fuel pressure of an internal combustion engine to be higher than atmospheric pressure by a constant pressure, and an estimation means for estimating a pressure at an injector tip in the intake passage from an engine operating state, Correction coefficient calculating means for calculating a correction coefficient from the value obtained by the estimating means; fuel for correcting the target fuel injection amount with the correction coefficient obtained by the correction coefficient calculating means; and performing fuel injection control with the corrected value Fuel injection for an internal combustion engine including injection amount control means, injection timing changing means for changing the injection timing according to the engine operating state, and first correction means for correcting the correction coefficient in accordance with the injection timing. Quantity control device. 2. An injector provided in the intake passage, a pressure regulator for adjusting the fuel pressure of the internal combustion engine to be higher than atmospheric pressure by a constant pressure, and an estimating means for estimating the pressure at the tip of the injector in the intake passage from the engine operating state, Correction coefficient calculating means for calculating a correction coefficient from the value obtained by the estimating means; fuel for correcting the target fuel injection amount with the correction coefficient obtained by the correction coefficient calculating means; and performing fuel injection control with the corrected value An injection amount control means, a valve timing changing means for changing the valve timing of the intake valve of the internal combustion engine according to the engine operating state, and a second correcting means for correcting the correction coefficient corresponding to the valve timing. Fuel injection amount control device for internal combustion engine.