JP2623512B2 - Control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for an internal combustion engine capable of changing valve operating characteristics of an intake valve and / or an exhaust valve, and more particularly, to a point in which fuel injected into an intake pipe of the engine adheres to an intake pipe wall. The present invention relates to an apparatus for controlling a fuel injection amount in consideration of the above.

[0002]

2. Description of the Related Art In an engine of the type in which fuel is injected into an intake pipe, there is a problem that a part of the injected fuel adheres to an intake pipe wall and a required amount of fuel is not sucked into a combustion chamber. In order to solve this problem, the amount of fuel adhering to the intake pipe wall and the amount of adhering fuel vaporized and drawn into the combustion chamber are predicted, and the fuel injection amount is determined in consideration of these predicted amounts. A fuel supply control method for controlling the fuel supply is conventionally known (Japanese Patent Application Laid-Open No. 61-126337).

[0003] Further, there has been conventionally known an internal combustion engine in which the valve operating characteristics of the intake valve and the exhaust valve, that is, the valve timing and the valve lift amount can be changed during the operation of the engine (for example, JP-B-2-50285). .

[0004]

When the above-described control method is applied to the above-mentioned internal combustion engine, a desired air-fuel ratio cannot be obtained by simply combining the two, and more accurate air-fuel ratio control is performed. There was room for improvement above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made to reduce the air-fuel ratio of an air-fuel mixture supplied to a combustion chamber of an internal combustion engine in which the valve operating characteristics of an intake valve and / or an exhaust valve can be changed. It is an object of the present invention to provide a control device capable of controlling accurately.

[0006]

According to the present invention, there is provided a control apparatus for an internal combustion engine having a valve operating device capable of changing a valve operating characteristic of at least one of an intake valve and an exhaust valve. Supply fuel amount calculation means for calculating the amount of fuel to be supplied to the engine based on the rotation speed and load state of the engine, and adhesion fuel amount prediction means for predicting the amount of adhesion fuel adhering to the wall surface of the intake pipe of the engine; A removed fuel amount predicting means for predicting a removed fuel amount that is evaporated from fuel adhering to the intake pipe wall surface and carried away to the combustion chamber of the engine; and a fuel amount calculated by the supplied fuel amount calculating means. A supply fuel amount correction unit that corrects according to the attached fuel amount and the removed fuel amount, and a fuel injection unit that injects the amount of fuel corrected by the supply fuel amount correction unit into an intake pipe of the engine. Having In control device is obtained by so providing the predicted fuel amount correcting means for correcting the adherent fuel amount and the carried-away fuel amount in response to the valve operating characteristic.

[0007]

According to the present invention, the amount of adhered fuel and the amount of removed fuel are corrected in accordance with the valve operating characteristics of the intake valve and / or the exhaust valve.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram of an internal combustion engine and a control device thereof according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a DOHC in-line four-cylinder internal combustion engine (internal combustion engine, hereinafter simply referred to as "engine") provided with a pair of intake valves and exhaust valves (not shown) for each cylinder. is there. In the engine 1, the valve timings of the intake valve and the exhaust valve are determined by a high-speed valve timing (high-speed V / T) suitable for a high-speed rotation region and a low-speed valve timing (low-speed V / T) suitable for a low-speed rotation region. And a valve timing switching mechanism 19 capable of switching between the two stages.
The switching of the valve timing in the present embodiment includes the switching of the valve lift.

A throttle body 3 is provided in the middle of an intake pipe 2 of the engine 1, and a throttle valve 3 'is provided therein.
Is arranged. A throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3 ′, and outputs an electric signal according to the opening of the throttle valve 3 ′ to output an electronic control unit (hereinafter referred to as “ECU”) 5. To supply.

The fuel injection valve 6 is connected between the engine 1 and the throttle valve 3 'and to a fuel pump (not shown) of the intake pipe 2 and is also electrically connected to the ECU 5 to control the EC.
The valve opening time of fuel injection is controlled by a signal from U5.

A branch pipe 7 is provided downstream of the throttle valve 3 ′ of the intake pipe 2, and an absolute pressure (PBA) sensor 8 is attached to a tip of the branch pipe 7. The PBA sensor 8 is electrically connected to the ECU 5, and
The absolute pressure PBA is converted into an electric signal by the PBA sensor 8 and supplied to the ECU 5.

An intake air temperature (TA) sensor 9 is mounted on the pipe wall of the intake pipe 2 downstream of the branch pipe 7, and the intake air temperature TA detected by the TA sensor 9 is converted into an electric signal.
It is supplied to the ECU 5.

An engine coolant temperature (TW) sensor 10 composed of a thermistor or the like is inserted into the cylinder peripheral wall of the cylinder block of the engine 1 filled with coolant, and the engine coolant temperature TW detected by the TW sensor 10 is converted into an electric signal. The converted data is supplied to the ECU 5.

A cylinder discrimination (CYL) is provided at a predetermined position around a camshaft (not shown) or around a crankshaft of the engine 1.
Sensor 11, TDC sensor 12, crank angle (CRK)
Each of the sensors 13 is attached.

The CYL sensor 11 outputs a pulse signal (hereinafter referred to as "CYL signal pulse") at a predetermined crank angle position of a specific cylinder every two rotations of the crankshaft.
The YL signal pulse is supplied to the ECU 5.

The TDC sensor 12 outputs a signal pulse (hereinafter referred to as a “TDC signal pulse”) at a predetermined crank angle position every time the crankshaft of the engine 1 rotates by 180 °, and supplies the TDC signal pulse to the ECU 5. .

The CRK sensor 13 outputs a pulse signal (hereinafter referred to as "CRK") at a cycle of a TDC signal pulse, that is, at a constant crank angle cycle (for example, a 45 cycle) shorter than 180 degrees.
And outputs the CRK signal pulse to the ECU 5.

The output signal pulses of the CYL sensor 11, the TDC sensor 12, and the CRK sensor 13 indicate the fuel injection timing,
Various timing control such as ignition timing and engine speed N
Used to detect E.

In the middle of the exhaust pipe 14 of the engine 1, an oxygen concentration sensor (hereinafter referred to as “O ₂ sensor”) 15 is provided.
The oxygen concentration in the exhaust gas detected by the O ₂ sensor 15 is converted into an electric signal,
Supplied to

The valve timing switching mechanism 19
Has an electromagnetic valve (not shown) for performing switching control of valve timing. The electromagnetic valve is connected to the ECU 5, and the opening and closing operation thereof is controlled by the ECU 5. The solenoid valve switches the hydraulic pressure of the valve timing switching mechanism 19 between high and low, and the valve timing is switched between high-speed V / T and low-speed V / T according to the high / low of the hydraulic pressure. The hydraulic pressure of the switching mechanism 19 is a hydraulic pressure (Poil) sensor 1
The detection signal is supplied to the ECU 5.

The ECU 5 has an input circuit 5a having functions of shaping input signal waveforms from the above-described various sensors, correcting a voltage level to a predetermined level, converting an analog signal value to a digital signal value, and the like, and a central processing unit. Circuit (hereinafter “CP
U "), a storage means 5c comprising a ROM and a RAM for storing various calculation programs executed by the CPU 5b, various maps and calculation results to be described later, and solenoid valves of the fuel injection valve 6 and the switching mechanism 19. And an output circuit 5d for supplying a drive signal to the output circuit 5d.

FIG. 2 is a flowchart of a program for calculating the valve opening time of the fuel injection valve 6, that is, the fuel injection amount Tout. This program is executed every time a TDC signal is generated.

In step S1, it is determined whether or not the high-speed V / T is selected. If the answer is negative (NO), that is, if the low-speed V / T is selected, the direct rate for the low-speed V / T is selected. A and the carry-out rate B are calculated (step S2).

Here, the direct ratio A is the ratio of the fuel injected into a combustion chamber in a form including the amount of fuel injected by evaporation or the like during the cycle out of the fuel injected in a certain cycle. The leaving rate B is the proportion of the fuel adhering to the intake pipe wall up to the previous time, which is sucked into the combustion chamber due to evaporation or the like during the cycle. The direct rate A and the carry-out rate B are calculated based on the low-speed V / T A map and the B map set according to the engine coolant temperature TW and the intake pipe absolute pressure PBA.
The value is read according to the detected value of the value and the PBA value. At this time, the low-speed V / T
Direct rate A and carry-out rate B are calculated.

In the following step S3, correction coefficients KA and KB for the direct rate A and the carry-out rate B for the low-speed V / T are calculated. The correction coefficients KA and KB are set according to the engine speed NE by using the KA table and the KB table for the low-speed V / T shown in FIG. That is, the correction coefficient KA of the direct rate A and the correction coefficient KB of the carry-out rate B are NE
Each is set so as to increase as the value increases.

Here, when the engine speed NE increases, the correction coefficients KA and KB are increased because the intake flow velocity in the intake pipe is increased, so that the direct rate A and the carry-out rate B apparently increase. Because it becomes.

When the answer to step S1 is affirmative (YES), the high-speed V is set in the same manner as in steps S2 and S3.
/ T direct rate A and carry-out rate B and correction coefficient K for / T
A and KB are calculated (steps S4 and S5), and step S
Proceed to 6. That is, in step S4, A for high-speed V / T
The direct rate A and the carry-out rate B are read from the map and the B map, and in step S5, the high-speed V shown in FIG.
Using the KA table and the KB table for / T, the correction coefficients KA and KB for the high-speed V / T are calculated.

As described above, the A map and the B map for the high-speed V / T and the low-speed V / T are provided, and the KA table and the KB table for calculating the correction coefficient are also for the high-speed V / T and the low-speed V / T. Is provided separately because the flow velocity near the intake valve, which is one of the controlling factors of the fuel transfer parameter, and the pressure fluctuation due to it change depending on the opening / closing timing of the intake valve and the valve lift amount. is there. Accordingly, the direct rate A and the carry-out rate B show different tendencies depending on the valve timings.
The map, the KA table, and the KB table are set corresponding to this tendency.

In the following step S6, the following equation (1):
According to (2), the corrected direct rate Ae and the corrected carry-out rate Be
Is calculated, and (1-Ae) and (1-Be) are calculated (step S4), and the process proceeds to step S7.

Ae = A × KA (1) Be = B × KB (2) Note that the Ae value, the (1-Ae) value and the (1-Be) value are
Since it is used in the program of FIG. 3 described later, it is stored in the RAM in the ECU 5.

In step S8, it is determined whether or not the engine has been started. If the answer is affirmative (YES), the fuel injection amount Tout is calculated based on the basic fuel amount Ti for starting (step S15). Exit this program. If the answer to step S8 is negative (NO), that is, if it is not the time of starting, the required fuel amount Tcyl (N) for each cylinder that does not include the addition correction term Ttotal described later is calculated by the following equation (3) (step S9). .

Tcyl (N) = TiM × Ktotal (N) (3) Here, (N) indicates a cylinder number, and a parameter to which this is assigned is calculated for each cylinder. TiM is a basic fuel amount at the time of normal operation (other than at the time of starting), and is calculated according to the engine speed NE and the intake pipe absolute pressure PBA. K
total (N) is a total correction coefficient (for example, engine water temperature correction coefficient KTW, lean correction coefficient K) calculated based on the engine operation parameter signals from various sensors.
LS etc.). However, the air-fuel ratio correction coefficient KO2 calculated according to the output of the O ₂ sensor 13 is not included.

In step S10, the following equation (4) is used.
The fuel supply amount TNET, which is the amount of fuel to be supplied to the combustion chamber of the corresponding cylinder by the current fuel injection, is calculated.

TNET = Tcyl (N) + Ttotal−Be × TWP (N) (4) Here, Ttotal is all addition correction terms calculated based on engine operation parameter signals from various sensors (for example, acceleration increase correction). Term TACC). However, it does not include the invalid time TV described later. TWP (N)
Is the intake pipe adhering fuel amount (predicted value) calculated by the program in FIG. 3, and (Be × TWP (N)) corresponds to the carry-out fuel amount in which the intake pipe adhering fuel is carried away to the combustion chamber. Since it is not necessary to newly inject the removed fuel amount, this amount is subtracted from the Tcyl (N) value in equation (4).

In step S11, it is determined whether or not the TNET value calculated by the equation (4) is larger than 0. If the answer is negative (NO), that is, if TNET ≦ 0, the fuel injection amount Tout is set to 0. Exit this program.
If the answer to step S11 is affirmative (YES), that is, TNET>
When it is 0, the Tout value is calculated by the following equation (5).

Tout = TNET (N) / Ae × KO2 + TV (5) Here, KO2 is an air-fuel ratio correction coefficient calculated based on the output of the O ₂ sensor 13, and TV is an invalid time correction term.

By opening the fuel injection valve 6 by the Tout value calculated by the equation (6), (TN)
An amount of fuel corresponding to ET (N) × KO2 + Be × TWP (N)) is supplied.

FIG. 3 is a flowchart of a program for calculating the amount of fuel TWP (N) adhering to the intake pipe. This program is used to generate a crank angle pulse that is generated every time the crankshaft rotates by a predetermined angle (for example, 30 degrees). Executed synchronously.

In step S21, it is determined whether or not the current execution of the program is within a period from the start of the calculation of the fuel injection amount Tout to the end of the fuel injection (hereinafter referred to as "injection control period"). If affirmative (YES),
The first flag FCTWP (N) is set to a value of 0 (step S32), and the program ends. Step S2
If the answer to 1 is negative (NO), that is, if it is not within the injection control period, it is determined whether or not the first flag FCTWP (N) is 1 (step S22). When the answer is affirmative (YES), that is, when FCTWP (N) = 1, the process immediately proceeds to step S31, and when negative (NO), that is, FCTW (N)
When P (N) = 0, it is determined whether or not fuel cut (fuel supply cutoff) is being performed (step S23).

When the answer to step S23 is negative (NO), that is, when fuel cut is not being performed, the intake pipe adhering fuel amount TWP (N) is calculated by the following equation (6) (step S2).
4), the second flag FTWPR (N) is set to a value of 0, and the first flag FCTWP (N) is set to a value of 1 (steps S30 and S31), and the program ends.

TWP (N) = (1−Be) × TWP (N) (n−1) + (1−Ae) × (Tout (N) −TV) (6) where TWP (N) (n -1) is the previous value of TWP (N), and Tout (N) is the latest fuel injection amount calculated by the program of FIG. The first term on the right side is
Of the fuel that has adhered last time, it corresponds to the amount of fuel remaining without being removed this time, and the second term on the right side corresponds to the amount of fuel that has newly adhered to the intake pipe of the fuel injected this time.

If the answer in step S23 is affirmative (YE
S), that is, during fuel cut, it is determined whether or not the second flag FTWPR (N) has a value of 1 (step S25). This answer is affirmative (YES), ie, FTWP
When R (N) = 1, the process immediately proceeds to step S31, and when negative (NO), that is, when FTWPR (N) = 0, the attached fuel amount TWP (N) is calculated by the following equation (7) (step S26). The process proceeds to step S27.

TWP (N) = (1−Be) × TWP (N) (n−1) (7) Equation (7) corresponds to the above equation (1) with the second term on the right-hand side deleted. . This is because the fuel is being cut and there is no newly attached fuel.

In step S27, it is determined whether or not the TWP (N) value is larger than a small predetermined value TWPLG. If the answer is affirmative (YES), that is, if TWP (N)> TWPLG, the process proceeds to step S30. If the answer to step S27 is negative (NO), that is, if TWP (N) ≦ TWPLG, then TWP (N) = 0 (step S28), and the second
The flag FTWPR (N) is set to a value of 1 (step S29), and the process proceeds to step S31.

The program shown in FIG. 3 allows the amount of fuel TWP (N) adhering to the intake pipe to be accurately calculated, and the calculated TWP (N) value is used for calculating the fuel injection amount Tout in the program shown in FIG. By doing so, it is possible to supply an appropriate amount of fuel to the combustion chamber of each cylinder in consideration of the amount of fuel attached to the intake pipe and the amount of fuel removed from the attached fuel.

In this embodiment, the direct rate A and the carry-out rate B are calculated and corrected in accordance with the selected valve timing. Therefore, the influence of the amount of fuel adhering to the intake pipe at each valve timing is accurately determined. And the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber can be accurately controlled to a desired value.

FIG. 5 is a diagram showing the overall configuration of an internal combustion engine and its control device according to a second embodiment of the present invention.
The engine 1 according to the present embodiment has a hydraulic drive valve unit 20 for hydraulically driving an intake valve and an exhaust valve instead of the valve timing switching mechanism 19. ECU5
Is connected to a solenoid in the hydraulic drive valve unit 20 and supplies control signals (θOFF and θON). A throttle body 3 is provided in the middle of the intake pipe 2, and a throttle valve 3 'is disposed inside the throttle body 3.
A motor 3a for driving the throttle valve is connected to the throttle valve 3 ', and the opening of the throttle valve 3' is controlled by an electric signal from the ECU 5. In a normal operating state, the throttle valve 3 'is controlled to an opening close to the full opening, and the opening period of the intake valve is controlled by the hydraulic drive unit 20.
Thus, the intake air amount of each cylinder of the engine 1 is controlled.

The ECU 5 includes a hydraulic drive valve unit 20 instead of the hydraulic pressure sensor 16 in the first embodiment.
Pressure sensor 1 for detecting the hydraulic pressure (Poil) of the hydraulic oil
6 'is further connected, an oil temperature sensor 18 for detecting an oil temperature Toil of hydraulic oil, a lift sensor 17 for detecting a lift amount (Lft) of an intake valve, and an accelerator pedal depression amount (θAC
An accelerator opening sensor for detecting C) is connected,
The detection signals of these sensors are supplied to the ECU 5.

The other parts are the same as those of the first embodiment (FIG. 1) denoted by the same reference numerals.

FIG. 6 is a sectional view of the hydraulic drive valve unit 20, which is mounted on the cylinder head 21 of each cylinder of the engine 1. Cylinder head 21
At the top of the combustion chamber (not shown) of the engine 1,
An intake valve port 23 is provided, the other of which communicates with the intake port 24. The intake valve 22 is disposed so as to be movable in the vertical direction in the drawing in the cylinder head 21 so as to open and close the intake valve port 23. A valve spring 26 is contracted between the flange 25 of the intake valve 22 and the cylinder head 21, and the intake valve 22 is biased upward (in a valve closing direction) by the valve spring 26. You.

On the other hand, a cam shaft 28 having a cam 27 is rotatably disposed on the left side of the cylinder head 21 in the drawing. The camshaft 28 is connected to a crankshaft (not shown) via a timing belt (not shown). Cam 27 and intake valve 2 formed integrally with cam shaft 28
2, a hydraulically driven valve unit 20 is interposed.

The hydraulic drive valve unit 20 includes a hydraulic drive mechanism 30 that opens and closes the intake valve 22 by pressing the intake valve 22 downward against the valve spring 26 in accordance with the profile of the cam 27, and a pressing force of the hydraulic drive mechanism 30. And a hydraulic release mechanism 31 for closing the intake valve 22 regardless of the cam profile.

The hydraulic drive mechanism 30 includes a cylinder head 21
A first cylinder body 33 fixed to a block 32 formed integrally with the first cylinder body 33 and a cylinder hole 33 of the first cylinder body 33 having a lower end (front end) abutting on an upper end (rear end) of the intake valve 25.
a, a valve-side piston (valve drive piston) 34 slidably fitted to the first cylinder body 33 and the valve-side piston 3
4, a second cylinder body 36 fixed to the block 32, a lifter 35 slidably in contact with the cam 27, and a lower end contacting the lifter 35 to form a second cylinder.
A cam-side piston 37 slidably fitted to a lower portion of the cylinder body 36, a hydraulic pressure generation chamber 39 defined by the second cylinder body 36 and the cam-side piston 37, a hydraulic pressure generation chamber 39, and a hydraulic pressure. An oil passage 40 connecting the chamber 38 is a main component, and the intake valve 22 is opened and closed according to the profile of the cam 27 when the hydraulic pressure in the working hydraulic chamber 38 is equal to or higher than a predetermined value.

The block 32 includes a flange 25 of the intake valve 22.
The lift sensor 17 is disposed at a position facing the.
The lift sensor 17 is connected to the ECU 5, detects a lift amount of the intake valve 22, and supplies a detection signal to the ECU 5.

On the other hand, the hydraulic pressure release mechanism 31 is
Oil passage 41 connecting oil supply gallery 42 with oil passage 4
1, a spill valve 45, a feed valve 43 and a check valve 44 disposed in the oil passage 41, and an accumulator circuit 41a defined by these valves 43, 44 and the spill valve 45. An accumulator 46 for maintaining the oil pressure at a predetermined value is a main component. The oil supply gallery 42 is provided for supplying oil pressure to a hydraulic drive valve unit provided for each cylinder.
It is connected to the. The oil pump 47 supplies hydraulic oil in an auxiliary oil pan 48 provided in the cylinder head 21 to the oil supply gallery 42 as oil pressure within a predetermined range. The hydraulic oil supplied to the oil supply gallery 42 may be supplied by an oil pump from an oil pan provided below the crankcase (not shown).

The spill valve 45 includes a control valve unit 100 and
And an electromagnetic drive unit 200 for driving the control valve unit 100.

In the spill valve 45, the electromagnetic drive unit 2
00 solenoid 202 is demagnetized, the spill valve 45
Opens, and when the solenoid 202 is excited, the spill valve 45 is closed.

The solenoid 202 is connected to the ECU 5, and the demagnetization / excitation is controlled by a control signal from the ECU 5.

The accumulator 46 includes an accumulator circuit 41
In order to maintain the hydraulic pressure in a at a predetermined pressure, the accumulator circuit 4
1a, a cap 463 having a cylinder hole 461 formed in the block 32 and having an air hole 462.
And a piston 464 slidably fitted in the cylinder hole 461, and a spring 465 compressed between the cap 463 and the piston 464.

The hydraulic drive mechanism 30 configured as described above
The operation of the hydraulic release mechanism 31 will be described below.

The spill valve 4 is controlled by a control signal from the ECU 5.
5 is energized, the spill valve 45 is closed, and the hydraulic pressure in the hydraulic pressure generating chamber 39, the oil passage 40, and the operating hydraulic chamber 38 of the hydraulic drive mechanism 30 is maintained at a high pressure (not less than a predetermined value). Then, the opening and closing drive of the intake valve 22 according to the profile of the cam 27 is performed. Therefore, the valve operating characteristics in this case (the relationship between the crank angle and the valve lift)
Is as shown by the solid line in FIG.

On the other hand, when the solenoid 202 of the spill valve 45 is demagnetized by a control signal from the ECU 5 when the intake valve 22 is opened, the spill valve 45 is opened, and the hydraulic pressure generation chamber 39 of the hydraulic drive mechanism 30 and the oil The oil pressure in the passage 40 and the working oil pressure chamber 38 decreases, and the intake valve 22 starts the valve closing operation regardless of the profile of the cam 27. The valve operating characteristic in this case is as shown by the broken line in FIG. That is, when the solenoid 202 is demagnetized at the crank angle θOFF in the same drawing, the intake valve 22 is slightly delayed from θOFF (θ = θST).
Starts the valve closing operation, and enters a valve closing completed state at θ = θIC (hereinafter referred to as “intake valve closing timing”).

As described above, the spill valve 45 is opened and closed by the control signal from the ECU 5 and the operation of the hydraulic drive mechanism 30 is invalidated when the spill valve 45 is opened, so that the closing start timing of the intake valve 22 can be set to an arbitrary value. Can be set to As a result, the intake air amount of each cylinder can be controlled by the control signal of the ECU 2.

In this embodiment, the same hydraulic drive valve unit as the intake valve side is provided on the exhaust valve side (not shown).
However, the exhaust valve side opens / closes like a normal valve operating mechanism that closes at a fixed timing according to the cam profile, or a valve timing switching mechanism in the first embodiment.
A variable valve timing mechanism that can set a plurality of valve closing timings may be used. In the following description, a parameter on the exhaust valve side corresponding to the intake valve closing timing θIC is referred to as an exhaust valve closing timing θEC.

FIG. 8 shows the fuel injection amount Tou in this embodiment.
It is a flowchart of a t calculation program, and corresponds to FIG. 2 in the first embodiment.

In step S41, valve timing parameters, specifically, intake valve closing timing θIC and exhaust valve closing timing θEC are read.

In step S42, the detected engine speed NE is detected using the A table and the B table set according to the engine speed NE as shown in FIG.
The direct rate A and the carry-out rate B corresponding to the engine water temperature are calculated, and the KATW table and the KBTW table set according to the engine water temperature TW as shown in FIG. Water temperature correction coefficient KA
Calculate TW and KBTW. Here, the values in the table shown in FIG. 9 are set to values based on 50% output of the engine maximum output at each engine speed. In step S42, reference values Abase and Bbase of the direct rate and the carry-out rate are calculated by the following equations (8) and (9).
Proceed to step S43.

Abase = A × KATW (8) Bbase = B × KBTW (9) In step S43, the KAIC table set as shown in FIG. 10A according to the intake valve closing timing θIC and Using the KBIC table, intake-side correction coefficients KAIC and KBIC of the direct rate and the carry-out rate are calculated. Further, a KAEC table and a KA table which are set as shown in FIG.
Exhaust correction coefficients KAEC and K using the BEC table
BEC is calculated, and the reference value correction coefficients KA and KB are calculated by the following equation (1).
0) and (11). In this embodiment,
In FIG. 10, as the θIC value and θEC value increase, the opening period of the intake valve and the exhaust valve decreases (θ in FIG. 7).
The IC moves to the left).

KA = KAIC × KAEC (10) KB = KBIC × KBEC (11) In the following step S44, the corrected direct rate Ae and the corrected carry-out rate Be are calculated by the following equations (12) and (13). ,
Proceed to step S7.

Ae = Abase × KA (12) Be = Bbase × KB (13) Steps S7 to S14 are steps S7 to S1 in FIG.
Same as 4.

The calculation of the intake pipe adhering fuel amount TWP (N) is performed by the program shown in FIG.

According to this embodiment, the direct rate A and the carry-out rate B are corrected in accordance with the closing timing of the intake valve and the exhaust valve, so that the intake pipe is independent of the closing timing of the intake valve and the exhaust valve. The amount of adhering fuel and the amount of removed fuel can be accurately predicted, and the air-fuel ratio of the mixture supplied to the combustion chamber can be accurately controlled to a desired value.

The calculation method of the direct rate A and the carry-out rate B in the above-described first and second embodiments uses the operation of a part of the plurality of intake valves and / or exhaust valves during the low load operation of the engine. The present invention can be applied to a case where the operation is stopped.

[0076]

As described above in detail, according to the present invention, the amount of adhering fuel and the amount of removed fuel are corrected according to the valve operating characteristics of the intake valve and / or the exhaust valve. Regardless, the amount of adhering fuel can be accurately predicted, and the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber can be accurately controlled to a desired value.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an internal combustion engine and a fuel supply control device thereof according to a first embodiment of the present invention.

FIG. 2 is a flowchart of a program for calculating a fuel injection time (Tout).

FIG. 3 is a flowchart of a program for calculating an intake pipe attached fuel amount (TWP (N)).

FIG. 4 is a diagram showing a table for calculating correction coefficients for a direct rate (A) and a carry-out rate (B).

FIG. 5 is a configuration diagram of an internal combustion engine and a fuel supply control device thereof according to a second embodiment of the present invention.

6 is a sectional view of a hydraulically driven valve unit of the engine of FIG.

FIG. 7 is a diagram for explaining an operation characteristic of an intake valve of the engine of FIG. 5;

FIG. 8 is a flowchart of a program for calculating a fuel injection time (Tout).

FIG. 9 is a diagram showing a table used for calculating a direct rate (A) and a carry-out rate (B).

FIG. 10 is a diagram showing a table used for calculating correction coefficients for a direct rate (A) and a carry-out rate (B).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake pipe 5 Electronic control unit (ECU) 6 Fuel injection valve 19 Valve timing switching mechanism 20 Hydraulic drive valve unit

Claims (1)

(57) [Claims] 1. A control device for an internal combustion engine having a valve operating device capable of changing at least one valve operating characteristic of an intake valve and an exhaust valve. Supply fuel amount calculation means for calculating the amount of fuel to be calculated, adhesion fuel amount estimation means for estimating the amount of adhesion fuel adhering to the wall of the intake pipe of the engine, and evaporating from the fuel adhering to the intake pipe wall. The removed fuel amount predicting means for predicting the removed fuel amount removed to the combustion chamber of the engine, and the fuel amount calculated by the supplied fuel amount calculating means is calculated according to the attached fuel amount and the removed fuel amount. A control unit comprising: a supply fuel amount correction unit that corrects the fuel supply amount; and a fuel injection unit that injects the amount of fuel corrected by the supply fuel amount correction unit into an intake pipe of the engine. Adhesion A control device for an internal combustion engine, comprising a predicted fuel amount correction means for correcting a fuel amount and a removed fuel amount.