JPH1113493A - Intake-air controller for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have an function equal to a variable timing device without controlling a valve opening period (valve timing) by an intake valve, and to control an intake period of time at each cylinder. SOLUTION: A throttle valve opening or closing inlet passage at each cylinder is installed in place just upstream each intake valve of respective cylinders, and a throttle actuator opening or closing and driving this throttle valve is equipped there. In an electronic control unit, on the basis of engine driving condition, a valve opening period of the throttle valve, namely, valve opening period TMG open and valve closing period TMG close of each throttle valve are set up. In succession, with these TMG open and close periods, each throttle valve is opened or closed in response to the valve opening period of the intake valve at each cylinder via the throttle actuator, whereby an effective intake period of time is thus controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an intake control valve for opening and closing an intake passage for each cylinder immediately upstream of an intake valve of each cylinder. The present invention relates to an intake control device for an engine that variably sets a valve opening period of an intake control valve and opens and closes the intake control valve to control the intake period.

[0002]

2. Description of the Related Art Conventionally, in order to achieve both output performance in a low to middle speed range of an engine and output performance in a high speed range, the opening / closing timing of an intake valve, that is, a valve opening period (valve timing) and a lift in accordance with an engine operating state have been conventionally known. Various variable valve timing lift devices and variable valve timing devices that change the amount in multiple stages or continuously have been proposed.

This multi-stage variable valve timing lift apparatus comprises a wide-angle, high-speed intake cam having a valve lift characteristic as shown in FIG. 29 (a) and a narrow-angle, low-speed, low-lift intake cam having a valve lift characteristic shown in FIG. An intake cam is provided, and the intake valve is operated by the high-speed intake cam in the middle and high load and high rotation ranges, and is operated by the low speed intake cam in the low and middle rotation ranges.

In a continuously variable valve timing lift device, for example, an intake cam whose valve lift and valve opening angle continuously change in an axial direction is provided on a camshaft of an engine, and the camshaft or the intake cam is provided. By moving in the axial direction, as shown in FIG. 29B, in the low-load low-rotation range, the opening period of the intake valve is narrowed, the lift amount of the intake valve is reduced, and the high-load high-speed , The valve opening period of the intake valve is continuously widened and the lift amount is increased. In addition, according to this continuously variable valve timing device, it is possible to control intake air continuously, and it is possible to perform load control even if the throttle valve is abolished, thereby improving fuel efficiency at the time of partial load. can do.

Further, a continuously variable valve timing apparatus is disclosed in Japanese Patent Application Laid-Open No. 8-45009 and Japanese Patent Application Laid-Open No. 8-93423.
As shown in FIG. 29, the phase of the camshaft, that is, the phase of the cam is changed with respect to the cam pulley by hydraulic pressure or the like in accordance with the operating state of the engine. In the rotation range, the opening period of the intake valve is advanced, and the opening period of the intake valve is retarded as the engine shifts to the idling state or the high rotation range. Further, according to the continuously variable valve timing device, the opening period of the intake valve is advanced in a low-load medium-low rotation region or the like (EGR region) in which nitrogen oxides (NOx) in exhaust gas increase. Thus, it is possible to ensure the valve overlap between the exhaust valve and the intake valve and perform so-called internal exhaust gas recirculation (internal EGR) in which exhaust gas is blown back to the intake system. Then, the combustion temperature is reduced by the internal EGR, and the emission amount of NOx can be reduced.

However, in the above-described variable valve timing lift devices and variable valve timing devices, the cam is used to open the intake valve during the valve opening period (valve timing).
And the lift amount of the intake valve is controlled, so that all cylinders are controlled uniformly, and it is not possible to perform full load output performance control for improving engine output performance or internal EGR control for each cylinder in a full load region.

To cope with this, the base cam profile of the intake cam is partially modified via hydraulic pressure,
A lost motion type or an electromagnetically driven type intake valve that operates an intake valve (Japanese Patent Application Laid-Open No. 2-181111) has been proposed.

In the lost motion method, as shown in FIG. 30, the operation of the intake cam 101 is transmitted to an intake valve 104 via a piston 102 and oil 103. Then, by controlling the solenoid valve 105 according to the engine operating state and adjusting the oil drain amount by the solenoid valve 105, the oil pressure of the oil 103 pumped through the pump 106 and the check valve 107 is controlled, and the intake air is controlled. Cam 101
For the basic valve opening period and lift amount of the intake valve 104 realized by the base cam profile,
The valve opening period (valve timing) and the lift amount can be continuously changed.

As shown in FIG. 31, an electromagnetically driven intake valve includes a core 1 provided integrally with an intake valve 110.
11, a valve opening excitation coil 112 for opening and closing the intake valve 110, a valve closing excitation coil 113, and springs 114 and 115 for urging the core 111 in the valve closing direction and the valve opening direction, respectively. Be composed. By turning on (energizing) the valve-opening excitation coil 112 and turning off (de-energizing) the valve-closing excitation coil 113, the core 111 is attracted in the valve-opening direction by the exciting force of the valve-opening excitation coil 112. Then, the intake valve 110 is opened. Conversely, turning off the valve opening excitation coil 112 and turning on the valve closing excitation coil 113 causes the excitation force of the valve closing excitation coil 113 to close the intake valve 110.

Therefore, the valve opening excitation coil 112 and the valve closing excitation coil 113 are turned ON and OFF according to the engine operating state.
By performing the OFF control, the valve opening period (valve timing) of the intake valve 110 can be controlled for each cylinder.

[0011]

However, in the case of the above-mentioned lost motion system, stable operation cannot be obtained in a wide temperature range due to a change in viscosity due to the temperature of oil serving as a working fluid. There is a disadvantage that it is not possible to obtain an appropriate opening period of the intake valve. Especially when the oil temperature is low, such as when the engine is cold,
The viscosity of the oil is high, and the above problem becomes remarkable.

In the case of an electromagnetically driven intake valve, the sealing required when the intake valve is closed is high, and the sealing performance when the intake valve is closed is ensured, and the intake valve is stably operated. In order to operate, it is necessary to set a large biasing force of the spring, and to increase the exciting force of the exciting coil to drive the intake valve against the biasing force. For this reason, when the battery voltage is reduced, for example, when starting the engine where the electric energy required for driving the intake valve is large and the electric load of the battery is large, not only the intake valve cannot be operated stably, but also the opening and closing of the intake valve There is a possibility that the device itself cannot be used.

Further, since the electromagnetically driven intake valve is disposed on the cylinder head of the engine, and the intake valve itself is considerably heated by the combustion heat, there is a problem that the electromagnetic performance is deteriorated due to the high temperature.

In view of the above circumstances, the present invention has a function equivalent to that of the variable valve timing device without controlling the valve opening period (valve timing) by the intake valve, and can control the intake period for each cylinder. Therefore, it is an object of the present invention to provide an intake control device for an engine that can always obtain a stable operation.

[0015]

In order to achieve the above object, an intake control apparatus for an engine according to the first aspect of the present invention, as shown in the basic configuration diagram of FIG. An intake control valve that is disposed immediately upstream and opens and closes an intake passage for each cylinder; a control valve driving unit that opens and closes the intake control valve; and a control valve driving unit that opens and closes the intake valve based on an engine operating state. A control means for variably setting the valve opening period of the intake control valve, and controlling the intake period by opening and closing each intake control valve via the control valve driving means for each cylinder according to the valve opening period of the intake control valve. It is characterized by having.

According to a second aspect of the present invention, in the first aspect of the present invention, the control means fixes the intake control valves of all the cylinders at a predetermined opening at the time of engine stall or engine start.

The intake control device for an engine according to the third aspect of the present invention is disposed immediately upstream of the intake valve of each cylinder, as shown in the basic configuration diagram of FIG. An intake control valve that opens and closes, a control valve drive unit that opens and closes the intake control valve, and an idle speed control valve that is disposed in a bypass passage that bypasses the intake control valve and is connected to the intake passage. An extremely low load determining means for determining whether the operation is an extremely low load operation, and at the time of the extremely low load operation, the intake control valves of all cylinders are fully closed and the intake air amount is controlled by the idle speed control valve, On the other hand, in the operation state except for extremely low load, the opening period of the intake control valve within the opening period of the intake valve is variably set based on the engine operation state,
Control means for controlling the intake period by opening and closing each intake control valve via the control valve driving means for each cylinder according to the opening period of the intake control valve.

According to a fourth aspect of the present invention, in the third aspect of the invention, the control means fully closes the intake control valves of all cylinders at the time of engine stall or engine start, and performs the idle rotation based on the engine temperature. It is characterized in that the opening of the number control valve is set.

According to a fifth aspect of the present invention, in the first to fourth aspects, the opening period of the intake control valve is set based on a required load and an engine speed. .

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the opening period of the intake control valve is corrected in accordance with an engine warm-up state.

According to a seventh aspect of the present invention, in the first aspect of the invention, the control means sets a target intake air amount based on a required load and an engine speed. The opening period of the intake control valve is corrected based on a deviation between the intake air amount and the actually detected intake air amount.

According to an eighth aspect of the present invention, in the first to sixth aspects of the present invention, the control means is configured to control a difference between a target air-fuel ratio set according to an engine operating state and an actually detected air-fuel ratio. , The deviation between the target intake air amount and the actual intake air amount is estimated, and the opening period of the intake control valve is corrected based on the deviation.

According to a ninth aspect of the present invention, in the first aspect of the present invention, the control means fixes the intake control valve at a predetermined opening when the intake control system is abnormal.

According to a tenth aspect of the present invention, in the third aspect of the present invention, the control means opens the intake control valve by a predetermined amount when the intake control system is in an abnormal state and in an operation state other than an extremely low load. It is characterized by being fixed every time.

According to an eleventh aspect of the present invention, in the first to eighth aspects of the present invention, the control means sets at least the opening timing of the intake control valve when the engine operating state is in the internal exhaust gas recirculation region. It is characterized in that the advance angle is corrected.

According to a twelfth aspect of the present invention, in the first or third aspect of the present invention, the control means fully opens the intake control valve of a predetermined cylinder when the operating state is in a cylinder deactivation region in which cylinder deactivation is performed. In addition to fixing the cylinder, at least fuel injection to the cylinder is stopped and the cylinder is stopped.

According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the control means divides the cylinders into groups so that combustion is performed at regular intervals, and alternately suspends the cylinder groups at predetermined intervals. It is characterized by the following.

According to a fourteenth aspect of the present invention, in the first or the third aspect of the present invention, the plurality of cylinders in which the opening periods of the intake valves do not overlap each other are grouped as one group, and the control valve driving means includes a cylinder group. Are driven collectively.

That is, according to the first aspect of the present invention, an intake control valve for opening and closing an intake passage for each cylinder is disposed immediately upstream of the intake valve for each cylinder, and a control valve for opening and closing each intake control valve. A driving means. Then, the opening period of the intake control valve within the opening period of the intake valve is variably set based on the engine operating state, and the opening period of the intake control valve is used to control each cylinder via control valve driving means. Each intake control valve is opened and closed to control the intake period.

According to the second aspect of the present invention, at the time of engine stall or engine start, the intake control valves of all cylinders are fixed at a predetermined opening.

According to the third aspect of the present invention, an intake control valve for opening and closing an intake passage for each cylinder is disposed immediately upstream of the intake valve for each cylinder, and control valve driving means for opening and closing each intake control valve. And a bypass passage bypassing the intake control valve and connected to the intake passage; and an idle speed control valve disposed in the bypass passage. Then, it is determined whether or not the operation is an extremely low load operation. When the operation is an extremely low load operation, the intake control valves of all cylinders are fully closed, and the intake air amount is controlled by the idle speed control valve. On the other hand, in the operation state except for the extremely low load, the opening period of the intake control valve within the opening period of the intake valve is variably set based on the engine operation state. Separately,
Each intake control valve is opened and closed via a control valve driving means to control the intake period.

According to the present invention, at the time of engine stall or engine start, the intake control valves of all cylinders are fully closed, and the opening of the idle speed control valve is set based on the engine temperature.

According to the fifth aspect of the invention, when the opening period of the intake control valve is set, the opening period of the intake valve is set based on the required load and the engine speed.

At this time, according to the present invention, the opening period of the intake control valve is corrected according to the engine warm-up state.

According to the present invention, a target intake air amount is set based on a required load and an engine speed, and the intake control is performed based on a deviation between the target intake air amount and an actually detected intake air amount. Correct the valve opening period.

According to the present invention, the target intake air amount and the actual intake air amount are determined based on the difference between the target air-fuel ratio set according to the engine operating state and the actually detected air-fuel ratio. Is estimated. The valve opening period of the intake control valve is corrected based on the deviation.

According to the ninth aspect of the present invention, when the intake control system is abnormal, the intake control valve is fixed at a predetermined opening.

According to the tenth aspect of the present invention, the intake control valve is fixed at a predetermined opening when the intake control system is in an abnormal state and the operation state except for an extremely low load is performed.

According to the eleventh aspect, when the engine operating state is in the internal exhaust gas recirculation region, at least the valve opening timing of the intake control valve is advanced.

In the twelfth aspect of the present invention, when the operating state is in the cylinder deactivation region in which the cylinder is deactivated, the intake control valve of the predetermined cylinder is fully opened and at least fuel injection to the cylinder is stopped to stop the cylinder. Pause.

In this case, according to the thirteenth aspect of the present invention, cylinders are divided into groups so that combustion is performed at equal intervals, and the cylinder groups are alternately stopped at predetermined intervals.

According to the fourteenth aspect of the present invention, the plurality of cylinders in which the valve opening periods of the intake valves do not overlap are grouped into one group, and the control valve driving means drives the intake control valves in this cylinder group collectively.

[0043]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 23 show a first embodiment of the present invention.

First, a schematic configuration of an engine employed in the present embodiment will be described with reference to FIG. In the figure, reference numeral 1 denotes an engine for a vehicle such as an automobile (in the figure, an in-line four-cylinder four-cycle gasoline engine), and an intake port 2a that communicates with a cylinder head 2 corresponding to each cylinder to a combustion chamber 3 respectively. And an exhaust port 2b.

The valve operating chamber 2c in the cylinder head 2
In addition, an intake camshaft 5 and an exhaust camshaft 6, which are interlocked with a crankshaft 4 of the engine 1 via a pulley and a timing belt (not shown) and make a half turn with respect to the crankshaft 4, are provided. An intake cam 5a and an exhaust cam 6a are formed on the intake cam shaft 5 and the exhaust cam shaft 6, respectively.

The intake port 2a and the exhaust port 2 are
It is opened and closed at a predetermined timing by an intake valve 7 and an exhaust valve 8 linked to the intake cam 5a and the exhaust cam 6a, respectively. That is, the intake valve 7 and the exhaust valve 8 are opened and closed by a normal conventional valve operating mechanism.

The base cam profile of the intake cam 5a is formed to have a wider opening angle and a higher lift than usual, thereby opening the intake valve 7 (valve timing) as shown in FIG. Is widened, and the valve lift of the intake valve 7 is increased. In the present embodiment, for example, the opening timing of the exhaust valve 8 is
54 ° C before exhaust stroke, that is, before BDC
A, The valve closing timing is set to 14 ° CA after the exhaust top dead center (TDC). The valve opening timing of the intake valve 7 is set to 20 ° CA before the intake stroke, that is, before exhaust TDC, and the valve closing timing is set to 60 ° CA after the intake stroke (after intake BDC). Therefore, from 20 ° CA before the exhaust TDC to 14 ° after the exhaust TDC
During CA, a valve overlap period of the intake valve 7 and the exhaust valve 8 is secured.

On the other hand, in the intake system of the engine 1, an intake manifold 9 is communicated with each intake port 2a, and an intake pipe 11 is communicated with the intake manifold 9 via an air chamber 10 in which intake passages of respective cylinders are gathered. I have. An air cleaner 12 is mounted on the upstream side of the intake pipe 11, and the air cleaner 12 communicates with the air intake chamber 13.

Further, as the immediately upstream of the intake valve 7 of each cylinder,
Each intake manifold 9 is provided with a butterfly type throttle valve 14 as an example of an intake control valve that opens and closes an intake passage for each cylinder (see FIG. 17).

The throttle valve 14 is not mechanically connected to the accelerator pedal 15, but is controlled by an electromagnetically driven throttle actuator 16 provided for each cylinder as an example of control valve driving means. It is turned. FIG.
As shown in FIG. 8, the throttle valve 14 is connected to the throttle actuator 16 through a throttle lever 17.
It is configured in conjunction with.

The throttle actuator 16 is
A rod 16a pivotally supported at one end by the throttle lever 17, and a core 1 provided integrally with the rod 16a.
6b, the valve-opening exciting coil 16c, the valve-closing exciting coil 16d for opening (fully opening) and closing (fully closing) the throttle valve 14 respectively, and the core 16b for the throttle valve closing direction and the valve opening direction, respectively. Spring 16e biasing the
16f.

In this embodiment, the electronic control unit (hereinafter referred to as "ECU") 40 energizes (hereinafter, "ON") the valve opening excitation coil 16c and de-energizes the valve closing excitation coil 16d. (Hereinafter, "OFF"), the rod 16a projects through the core 16d by the exciting force of the valve opening exciting coil 16c. Then, the projection of the rod 16a causes the throttle valve 14 to rotate counterclockwise through the throttle lever 17 in FIG. 18, and as shown by the dashed line in FIG.
4 is fully open.

Conversely, the valve opening excitation coil 16c is
When the FF is performed and the valve closing excitation coil 16d is turned on, the core 16b is excited by the valve closing excitation coil 16d.
The rod 16a is retracted via the. When the rod 16a retreats, the throttle valve 14 rotates clockwise via the throttle lever 17, and the throttle valve 14 is fully closed as shown by the broken line in FIG. As will be described in detail later, when both the excitation coils 16c and 16d are turned off, the throttle valve 14 is appropriately controlled to secure the engine startability and the minimum required vehicle running as shown by the two-dot chain line in FIG. Each spring 16 of the throttle actuator 16 is fixed at a predetermined small opening.
The urging forces e and 16f are set.

Accordingly, the ECU 40 controls the ON / OFF of the valve opening excitation coil 16c and the valve closing excitation coil 16d of each throttle actuator 16, and as shown in FIG. By controlling the valve opening timing and the valve closing timing of the valve 14, the effective intake period can be controlled for each cylinder. That is, it is possible to adopt a conventional normal valve operating mechanism and to provide a function equivalent to that of the variable valve timing device without controlling the valve opening period (valve timing) of the intake valve 7 itself.

As described above, the base cam profile of the intake cam 5a is formed to have a wider opening angle and a higher lift than usual. Therefore, based on the wide opening angle and high lift of the intake valve 7 by the intake cam 5a, the throttle valve 14
, The control range of the effective intake period can be widened.

Further, since the throttle valve 14 is electrically opened and closed by the ECU 40 via the throttle actuator 16, stable operation can be obtained even when the engine is cold.

Further, the sealing property of the throttle valve 14, which is required when the throttle valve is fully closed, is sufficiently lower than the sealing property of the intake valve 7, and the springs 16e, 16f of the throttle actuator 16 are provided with both exciting coils 16c, 16d.
When both are turned off, it is only necessary to have an urging force enough to fix the throttle valve 14 to a predetermined small opening degree. Therefore, the exciting coil 1 for driving the throttle valve 14 against the biasing force of the springs 16e and 16f.
The excitation force of 6c and 16d is small, and the throttle valve 1
4 requires less electric energy. Thus, the throttle valve 14 can be operated stably even when the battery voltage is reduced, and the intake period can be appropriately controlled for each cylinder.

The throttle actuator 16 is
Since it is provided alongside the intake manifold 9, the influence of electromagnetic performance deterioration due to high temperature is small and high reliability can be realized.

The above-mentioned butterfly type throttle valve 1
19, a rotary valve type throttle valve 18 may be employed as shown in FIG. In this case, as shown in the figure, the throttle valve 18 is configured to rotate by a throttle actuator 19 using, for example, a rotary solenoid.

The throttle actuator 1
Reference numeral 9 denotes a valve opening exciting coil 19a and a valve closing exciting coil 19b for opening (fully opening) and closing (fully closing) the throttle valve 18, respectively, and closing and opening directions of the throttle valve 18 respectively. , And each spring (not shown) biases the spring. The throttle actuator 19 is provided with a stopper (not shown) for regulating the throttle valve 18 between a fully closed position and a fully opened position.

In this case, the ECU 40 turns on the valve-opening excitation coil 19a and turns off the valve-closing excitation coil 19b.
The throttle valve 18 is rotated in the valve opening direction by the exciting force a, and the throttle valve 14a is fully opened as shown in FIG. Conversely, the valve opening excitation coil 19a is turned off and the valve closing excitation coil 19b is turned off.
N, the throttle valve 18 is rotated clockwise in FIG. 20 by the exciting force of the valve closing excitation coil 19b, and the throttle valve 18 is fully closed as shown in FIG. 20 (c). Is done. Further, the dual excitation coils 19a,
When both 19b are turned off, as shown in FIG. 20B, the throttle valve 18 is set to be fixed at a predetermined small opening degree by the urging force of each spring (not shown).

In the following description, an example in which the butterfly type throttle valve 14 is employed will be described. However, when the rotary valve type throttle valve 18 is employed, the throttle valve 1 is used.
4, The throttle actuator 16, the valve opening excitation coil 16c, and the valve closing excitation coil 16d are replaced with the throttle valve 18, the throttle actuator 19, the valve opening excitation coil 19a, and the valve closing excitation coil 19b, respectively.

An injector 20 is provided for each cylinder, downstream of the throttle valve 14 of the intake manifold 3 and immediately upstream of each intake port 2a.

Further, for each cylinder of the cylinder head 2, a spark plug 2 exposing a discharge electrode at the tip to the combustion chamber 3 is provided.
The ignition plug 21 is connected to an igniter 23 via an ignition coil 22 provided for each cylinder.

In the exhaust system of the engine 1, an exhaust pipe 25 is communicated with a collection portion of an exhaust manifold 24 which communicates with each exhaust port 2 b of the cylinder head 2, and a catalytic converter 26 is interposed in the exhaust pipe 25. And is communicated with the muffler 27.

Next, sensors for detecting the engine operating state will be described. Immediately downstream of the air cleaner 12 of the intake pipe 11, a thermal intake air amount sensor 28 using a hot wire or a hot film is interposed. In addition, a knock sensor 30 is attached to the cylinder block 1a of the engine 1, and a cooling water temperature sensor 31 for detecting a cooling water temperature TW as an example of the engine temperature faces the cooling water passage of the cylinder block 1a. . Further, an O2 sensor 32 for detecting an air-fuel ratio state is provided upstream of the catalytic converter 32.

A crank angle sensor 34 composed of an electromagnetic pickup or the like is provided on the outer periphery of a crank rotor 33 which is mounted on the crankshaft 4 of the engine 1.
A cylinder discriminating sensor 36 composed of an electromagnetic pickup or the like is provided opposite to a cam rotor 35 connected to the intake camshaft 5 that makes a half turn with respect to the crankshaft 4.

An accelerator sensor 37 comprising a potentiometer or the like is also provided on the support portion of the accelerator pedal 15 for detecting a depression amount (accelerator stroke) ACS of the accelerator pedal 15 as a required load.

As shown in FIG. 21, the crank rotor 33 has protrusions 33a, 3
3b and 33c are formed, and these projections 33a and 33c are formed.
b, 33c are formed at positions before the compression top dead center (BTDC) θ1, θ2, θ3 of each cylinder (# 1, # 4 cylinder and # 3, # 2 cylinder). In the present embodiment, θ1 =
97 ° CA, θ2 = 65 ° CA, θ3 = 10 ° CA.

As shown in FIG. 22, projections 35a and 35b for discriminating cylinders are formed on the outer periphery of the cam rotor 35, and the projections 35a are located after the compression top dead center of the # 3, # 4 and # 2 cylinders. (ATDV) formed at the position of θ4, and the protrusion 35b
Is composed of two projections, and the first projection is the AT of the # 1 cylinder.
It is formed at the position of DCθ5. In the present embodiment, θ4 = θ5 = 20 ° CA.

As shown in the time chart of FIG. 12, the crank rotor 33 and the cam rotor 35 are rotated by the rotation of the crankshaft 4 and the camshaft 5 with the operation of the engine, and the projections 33a and 33b of the crank rotor 33 are rotated. , 33c are detected by the crank angle sensor 34, and θ1, θ
Each crank pulse of 2, θ3 (BTDC 97, 65, 10 ° CA) is output every 1/2 engine revolution (180 ° CA). On the other hand, each protrusion of the cam rotor 35 is detected by the cylinder discrimination sensor 36 between the θ3 crank pulse and the θ1 crank pulse, and the cylinder discrimination sensor 36
Output a predetermined number of cylinder discrimination pulses.

As will be described later, the ECU 40 calculates the engine speed NE based on the input interval time Tθ of each pulse output from the crank angle sensor 34, and calculates the order of the combustion strokes of the cylinders (in this embodiment, , # 1 cylinder → # 3
(Cylinder → # 4 cylinder → # 2 cylinder)
Based on the pattern of the cylinder discrimination pulse from No. 6 and the value counted by the counter, cylinder discrimination such as a cylinder subject to throttle valve control (next intake stroke cylinder), a cylinder subject to fuel injection, a cylinder subject to ignition, and the like is performed.

The ECU 40 determines whether the throttle actuator 16, the injector 20, the igniter 23
And the like, and outputs a drive signal corresponding to the control amount, that is, engine control such as intake control, fuel injection control, ignition timing control, and the like.
In the present embodiment, the fuel injection amount is set by the L jetronic method.

The ECU 40, as shown in FIG.
CPU 41, ROM 42, RAM 43, backup R
The AM 44, the counter / timer group 45, and the I / O interface 46 are configured around a microcomputer connected to each other via a bus line.
A constant voltage circuit 47 for supplying a stabilized power to each section,
A peripheral circuit such as a drive circuit 48 connected to the O interface 46 and an A / D converter 49 is built in.

The counter / timer group 45 includes various counters such as a free-run counter, a counter for counting the input of a cylinder discrimination sensor signal (cylinder discrimination pulse), a throttle opening timing timer, a throttle closing timing timer, and a fuel injection. Timer, ignition timer, periodic interrupt timer for generating a periodic interrupt, timer for measuring the input interval time of a pulse signal (crank pulse) input from the crank angle sensor 34, and watchdog timer for monitoring a system abnormality Are collectively referred to for convenience, and other various software counters and timers are used.

The constant voltage circuit 47 is connected to a battery 51 via a first relay contact of the power supply relay 50 having two circuit relay contacts. The battery 51 is connected to an ignition switch 52 (see FIG. 16). Is IG
Is connected to one end of a relay coil of the power supply relay 50, and the other end of the relay coil is connected to the A / D.
It is connected to a converter 49.

The constant voltage circuit 47 is connected to the battery 51 via a first relay contact of the power supply relay 50.
Not only connected to the battery 51 but also directly
When the ignition switch 52 is turned on and the relay contact of the power supply relay 50 is closed, power is supplied to each unit in the ECU 40. On the other hand, regardless of whether the ignition switch 52 is on or off, A power supply for backup is supplied to the backup RAM 44. A power supply line to each actuator extends from the second relay contact of the power supply relay 50.

The input ports of the I / O interface 46 include the knock sensor 30 and the crank angle sensor 3.
4. A cylinder discriminating sensor 36, a vehicle speed sensor 38, and a starter switch 39 for detecting an engine starting state are connected, and further, via the A / D converter 49, the intake air amount sensor 28, the cooling Water temperature sensor 31, O2
The sensor 32 and the accelerator sensor 37 are connected, and the ignition switch 52 and the power relay 50 are connected.
Is input and monitored.

On the other hand, the output port of the I / O interface 46 is connected to the valve opening excitation coil 16c, the valve closing excitation coil 16d, and the injector 20 of each of the throttle actuators 16 provided for each cylinder. The igniter 23 is connected while being connected via the circuit 48.

In accordance with the control program stored in the ROM 42, the CPU 41 processes the detection signals from the sensors and switches, which are input via the I / O interface 46, the battery voltage, and the like, and stores them in the RAM 43. Based on various data, various learning value data stored in the backup RAM 44, and fixed data stored in the ROM 42, the opening / closing valve timing, fuel injection amount, ignition timing, and the like of each throttle valve 14 are calculated for each cylinder. Then, engine control such as intake control, fuel injection control, and ignition timing control is performed.

In such an engine control system, EC
In U40, based on the engine operating state,
The opening period of the throttle valve 14 during the opening period of the intake valve 7, that is, the opening timing TMGOPEN of each throttle valve 14.
And the valve closing timing TMGCLOSE is set. The effective intake period is controlled by opening and closing each throttle valve 14 via the throttle actuator 16 for each cylinder based on the valve opening timing TMGOPEN and the valve closing timing TMGCLOSE (see FIG. 11).

That is, the function of the control means according to the present invention is realized by the ECU 40.

The specific control processing according to the present invention executed by the ECU 40 will now be described with reference to FIGS.
This will be described according to the flowchart shown in FIG.

When the ignition switch 52 is turned on,
When the power is supplied to the ECU 40, the system is initialized, and each flag and each counter are initialized except for data such as various learning values stored in the backup RAM 44. Then, the starter switch 39 is turned on.
When the engine 1 is started, the crank angle sensor 34
Each time the crank pulse is input from the
An engine speed calculation routine is executed to determine the cylinder and calculate the engine speed NE.

In this cylinder discriminating / engine rotational speed calculating routine, first, in step S1, the crank pulse from the crank angle sensor 34 inputted this time is θ1, θ2, θ3.
Is determined based on the input pattern of the cylinder discrimination pulse from the cylinder discrimination sensor 36. Then, in step S2, cylinder discrimination such as a throttle valve control target cylinder (next intake stroke cylinder), a fuel injection target cylinder, and an ignition target cylinder is performed based on the input pattern of the crank pulse and the cylinder determination pulse.

That is, as shown in the time chart of FIG. 12, for example, if there is a cylinder discrimination pulse input between the input of the previous crank pulse and the input of the current crank pulse, the current crank pulse is The crank pulse can be identified as a θ1 crank pulse, and the crank pulse input next time can be identified as a θ2 crank pulse.

When there is no cylinder discrimination pulse input between the previous and current crank pulse inputs and there is a cylinder discrimination pulse input between the last and previous crank pulses, the current crank pulse is identified as a θ2 crank pulse. Can,
The crank pulse input next time can be identified as the θ3 crank pulse. Further, when there is no cylinder discrimination pulse input between the previous and current times and between the last and last crank pulse inputs, the crank pulse input this time is θ
It can be identified as three crank pulses, and the next input crank pulse can be identified as a θ1 crank pulse.

Further, two cylinder discrimination pulses are input between the previous and current crank pulses (θ corresponding to the projection 35b).
(5 cylinder discrimination pulse), the next compression top dead center is #
The cylinders to be ignited can be determined to be # 3 cylinders, and the next cylinder to be controlled by the throttle valve (next intake stroke cylinder) #i and the cylinder to be fuel injected are # 2 Can be determined. Further, it is possible to determine the next cylinder and subsequent cylinders in the order of the combustion strokes (in this embodiment, # 1 cylinder → # 3 cylinder → # 4 cylinder → # 2 cylinder).

In the following step S3, the time from the previous crank pulse input to the present crank pulse input measured by the crank pulse input time counting timer, that is, the crank pulse input interval time (θ1 crank pulse and θ2 crank pulse) Input interval time Tθ1
2. The input interval time Tθ23 between the θ2 crank pulse and the θ3 crank pulse or the input interval time Tθ31 between the θ3 crank pulse and the θ1 crank pulse is read out, and the crank pulse input interval time Tθ is detected.

Then, the process proceeds to a step S4, wherein the angle between the crank pulses corresponding to the crank pulse identified this time is read, and the current engine speed NE is calculated based on the angle between the crank pulses and the pulse input interval time Tθ. Is stored at a predetermined address in the RAM 43 and the processing exits from the routine. Incidentally, the angle between the crank pulses is known,
In the present embodiment, the angle θ12 between the θ1 crank pulse and the θ2 crank pulse is 32 ° CA, θ2
The angle θ23 between the crank pulse and the θ3 crank pulse is 5
The angle θ31 between the 5 ° CA, θ3 crank pulse and the θ1 crank pulse is 93 ° CA.

Each data of the engine speed NE and the cylinder discrimination result (throttle valve control target cylinder) calculated by the cylinder discrimination / engine rotation speed calculation routine is used for setting the throttle valve opening / closing timing shown in FIGS. It is read out in a routine, and for each cylinder, the opening period of the throttle valve 14, that is, the opening timing TMG of each throttle valve 14,
OPEN and valve closing timing TMGCLOSE are set.

Next, the throttle valve opening / closing timing setting routine shown in FIGS. 3 and 4 will be described.

The throttle valve opening / closing timing setting routine is executed at predetermined intervals after the system initialization. First, in steps S11 and S12, the starter switch 39 is set.
An engine start determination is made based on the operating state of the engine and the engine speed NE.

Then, the starter switch 39 is turned ON, or the engine speed NE is set to a preset complete engine speed NE.
When the speed falls below SET (for example, 500 rpm) and it is determined that the engine is started or engine stalls, the process proceeds from the corresponding step to step S13. Then, steps S13 and S14
Then, both the valve opening excitation coil 16c and the valve closing excitation coil 16d of the throttle actuators 16 of all cylinders are turned off.
Then, in a succeeding step S15, a throttle valve operation prohibition flag FTH is set (FTH ← 1), and in a step S16, a cylinder deactivation control flag FCY instructing execution of cylinder deactivation control described later.
Clear L (FCYL ← 0) and exit the routine.

Therefore, when the engine is started or stalled, both exciting coils 16c and 16d of each throttle actuator 16 are turned off, so that the biasing forces of the springs 16e and 16f of the throttle actuator 16 cause the throttle valves of all cylinders to be throttled. As shown by a two-dot chain line in FIG. 18, 14 is fixed to a predetermined small opening degree (for a rotary valve type throttle valve, see FIG. 20B).

That is, when the engine stalls, the intake valve 7 does not open or close, and it is meaningless to open or close the throttle valve 14 at this time. To prevent unnecessary control. Further, at this time, since the throttle valve 14 is fixed at the predetermined small opening degree, even if the operation is shifted to the engine start, the intake air is secured and the engine start is prevented from being hindered.

When the engine is started, the electric load of the battery 51 is large due to the operation of a starter motor (not shown), and the power supply voltage (battery voltage VB) of the throttle actuator 16 is unstable. The opening / closing control of the throttle valve 14 is stopped, and FIG.
As shown in (c), a fixed throttle opening is set. still,
As described above, the fixed throttle opening at this time is determined by the springs 16e and 16e of the throttle actuator 16.
By the biasing force of f, the opening degree is set to an appropriate value so as to ensure the engine startability and the minimum required vehicle traveling, and the appropriate engine startability is ensured.

On the other hand, in steps S11 and S12, the starter switch 39 is turned off and the engine speed NE
When the engine speed is equal to or higher than the complete explosion speed NESET and the engine is in a normal operation after the complete explosion, the process proceeds to step S17 to diagnose the intake control system (throttle valve control system).

That is, the ECU 40 determines abnormalities in the crank angle sensor 34, the accelerator sensor 37 and the like, and the throttle actuator 16 and the like for detecting the parameters related to the throttle valve control by the self-diagnosis function. The sensor itself or the sensor and the ECU 40
If an abnormality such as disconnection or short-circuit occurs in the connector harness between them, the signal value input from the sensor to the ECU 40 indicates a value that cannot be normally taken, and the throttle actuator 16 itself or the throttle actuator 16 and E
If an abnormality such as disconnection or short circuit occurs in the connector harness between the CUs 40, the drain voltage of the throttle actuator 16 indicates an abnormal value. Therefore, the diagnosis in the ECU 40 is determined to be NG when the sensor system indicates a value that cannot be normally obtained, and when the drain voltage indicates an abnormal value for the throttle actuator system, the diagnosis is determined to be N.
J is determined.

When the sensor for detecting a parameter related to the throttle valve control or the throttle actuator 16 is abnormal, the process proceeds to step S13 and exits the routine via steps S13 to S16.

Therefore, when the intake control system (throttle valve control system) is abnormal, both the excitation coils 16c and 16d of each throttle actuator 16 are turned off, so that the throttle valves 14 of all cylinders have a fixed throttle opening. (See FIG. 14 (c)). As a result, the sensor for detecting the parameter related to the throttle valve control or the throttle actuator 16 or the like is abnormal,
Even if an abnormality occurs in the intake control system, the minimum required vehicle traveling is ensured.

On the other hand, when the system is normal in step S17, the process proceeds to step S18, where steps S18 and S19 are performed.
Then, based on the engine speed NE and the accelerator stroke (accelerator pedal depression amount) ACS representing the required load, the throttle opening angle table and the throttle closing basic angle table stored in the ROM 42 are referenced with interpolation calculation. , A throttle opening angle THAOPEN which determines the opening timing of the throttle valve 14, and a basic throttle closing angle T which determines the basic closing timing of the throttle valve 14.
Set HACLOSEBASE.

Each of the above tables shows the target intake air per cylinder per cycle appropriate for obtaining the target engine output for each region of the engine speed NE and the accelerator stroke ACS representing the required load by simulation or experiment in advance. The effective intake period (unit: crank angle) of the throttle valve 14 that is appropriate for obtaining the target intake air amount during the valve opening crank angle period of the intake valve 7 is obtained. Proper throttle opening angle THAOPEN and basic throttle closing angle T
HACLOSEBASE is set as a throttle opening angle table and a throttle basic closing angle table using the engine speed NE and the accelerator stroke ACS as parameters, respectively, and is stored in a series of addresses in the ROM 42.

In this embodiment, as shown in FIG. 12, the throttle valve opening angle THAOPEN is θ2
Based on the crank pulse input, it is set as a value that determines at what CA the throttle valve 14 is opened after the θ2 crank pulse is input. The basic throttle closing angle THACLOSEBASE is based on the input of the θ1 crank pulse, and is set to what degree CA after the input of the θ1 crank pulse.
Is set as a value that determines whether the throttle valve 14 is closed.

The throttle valve opening angle THAOPEN and the basic throttle valve closing angle THACLOSEBASE based on the above tables are shown.
The characteristics of are shown in FIG.

That is, when the accelerator stroke ACS is small and the required load is small, the required engine output is small, the target intake air amount is small, and the required effective intake period is short. Therefore, when the accelerator stroke is small and the load is low, the throttle opening angle THAOPEN for opening the throttle valve 14 and the throttle basic angle for closing the throttle valve 14 are set in order to set the opening period of the throttle valve small. Valve closing angle THACLOSEBASE
Are set to close values.

Then, as the required load increases, the required engine output increases, and the target intake air amount increases. Accordingly, as the required load increases due to an increase in the accelerator stroke ACS, the throttle opening angle THAOPEN is gradually advanced to increase the effective intake period due to the opening period of the throttle valve 14, and the throttle basic angle is increased. The valve closing angle THACLOSEBASE is retarded.

Further, as the engine speed NE increases,
In order to increase the target intake air amount and improve the charging efficiency, FIG.
As shown in FIG. 13 (c) at the time of medium rotation and at the time of high rotation of FIG. , The advance amount of the throttle opening angle THAOPEN and the retard amount of the basic throttle valve closing angle THACLOSEBASE are relatively increased.

As a result, at the time of high revolution full load (full accelerator stroke), the opening period of the throttle valve 14 is widened as shown in FIG. The period is determined. The maximum effective intake period increases the in-cylinder intake air amount, improves the charging efficiency, and increases the engine output.

As the required load and the engine speed NE decrease due to the accelerator stroke ACS, FIG.
As shown in (b), during the opening period of the intake valve 7, the opening period of the throttle valve 14 is narrowed, the effective intake period is reduced, and the engine output is reduced.

In the following step S20, the cooling water temperature sensor 3
1, a water temperature correction coefficient KT for correcting the throttle basic valve closing angle THACLOSEBASE according to the engine warm-up state by referring to a table based on the cooling water temperature TW according to 1.
Set W. That is, in the present embodiment, the idle speed control valve (ISC valve) is abolished.
It is necessary to substitute the function of the ISC valve by the throttle valve 14.

The water temperature correction coefficient KTW is determined based on the engine coolant temperature TW, that is, the engine warm-up state, by increasing the valve opening period of the throttle valve 14 when the engine temperature is low to increase the effective intake period, thereby obtaining the in-cylinder intake air. The purpose is to increase the amount to increase the idle speed and promote the warm-up of the engine. In the present embodiment, the throttle valve 14
The valve closing timing is retarded by the water temperature correction coefficient KTW to increase the effective intake period.

As shown in step S20, when the engine coolant temperature TW is low, the table shows that the effective intake period is increased by increasing the amount of retard correction with respect to the closing timing of the throttle valve 14, and the idling speed is increased. A water temperature correction coefficient KTW of a large value is stored to increase the number. Then, the water temperature correction coefficient KTW is decreased in accordance with the rise of the engine cooling water temperature TW. When the engine warm-up is completed, the water temperature correction advance angle KTW becomes KTW = 1.0, and there is no correction by the water temperature correction coefficient.

Next, at step S21, the engine speed NE
The learning value KLR is searched by referring to a learning value table composed of a series of addresses in the backup RAM 44 based on the acceleration stroke ACS representing the required load and the learning correction coefficient KTHLR is set by interpolation calculation, and the process proceeds to step S22. .

That is, as described above, the throttle valve 14
Is set so as to obtain the target intake air amount obtained for each region based on the engine speed NE and the accelerator stroke ASC representing the required load.

Therefore, according to the learning routine of FIG. 5 described later, the throttle for providing the effective intake period in accordance with the deviation of the actual intake air amount from the target intake air amount for each region based on the engine speed NE and the accelerator stroke ASC. A learning value KLR for correcting the valve opening period of the valve 14 is learned, and a learning correction coefficient K set by the learning value KLR.
By THLR, the basic throttle closing angle THACLOSEBAS
By correcting E, the opening period of the throttle valve 14 is corrected, and the intake air amount with respect to the target intake air amount due to variations in production of intake control systems such as the throttle valve 14 and the throttle actuator 16 and deterioration over time. To compensate for the deviation.

In step S22, the water temperature correction coefficient KT is added to the throttle basic closing angle THACLOSEBASE.
The water temperature is corrected by multiplying by W, and the learning correction coefficient KT is calculated.
A learning correction is performed by multiplying by HLR, and a throttle closing angle THACLOSE that determines the closing crank angle of the throttle valve is set (THACLOSE ← THACLOSEBASE × KTW × KTHLR).

In this embodiment, in order to enable internal exhaust gas recirculation (internal EGR), a valve overlap period of the exhaust valve 8 and the intake valve 7 is provided as shown in FIG. Accordingly, if the throttle valve closing angle THAOPEN, which determines the valve opening timing of the throttle valve 14, is corrected for water temperature or learned to correct the valve opening period of the throttle valve 14, the correction causes the valve opening timing of the throttle valve 14 to exceed the valve opening time. During the lap period, the internal EGR is performed even in a region that does not require the internal EGR, and the influence of the internal EGR deteriorates the combustibility.

For this reason, in this embodiment, only the throttle valve closing angle THACLOSE, which determines the throttle valve closing timing, is subjected to the water temperature correction and the learning correction. However, if the internal EGR is not taken into consideration, the valve opening timing of the throttle 14 is not changed. The water temperature correction and the learning correction may be performed only for the determined throttle valve opening angle THAOPEN, or for both the throttle valve opening angle THAOPEN and the throttle valve closing angle THACLOSE.

Next, in step S23, based on the engine speed NE, the accelerator stroke ACS, the vehicle speed VSP detected by the vehicle speed sensor 38, and the like, the driving state is set to idle, extremely low load, idle idle, or maximum vehicle speed limit.
It is determined whether or not the cylinder is in a cylinder rest area where the predetermined cylinder is stopped.

Then, when the operation state is the cylinder-stop region (idle,
Extremely low load, idle blowing or maximum vehicle speed limit etc.)
In step S24, the process proceeds to step S24, where the cylinder deactivation control flag F instructs cylinder deactivation control for deactivating a predetermined cylinder.
Set CYL (FCYL ← 1) and jump to step S29.

If the operation state is outside the cylinder stall region in step S23, the flow proceeds to step S25, the cylinder deactivation control flag FCYL is cleared (FCYL ← 0), and the flow proceeds to step S26.

In step S26, based on the engine speed NE, the accelerator stroke ACS, etc., the engine operating state is set to the internal EGR in the low-load, medium-low rotation region where the nitrogen oxides (NOx) in the exhaust gas increase. It is determined whether or not the internal EGR area is required. When the engine operation state is outside the internal EGR range, the process jumps to step S29.

On the other hand, when the engine operating state is the internal EGR region such as the low load, medium and low speed region, the process proceeds to step S27, and in steps S27 and S28, the throttle valve opening angle THAOPEN and the throttle valve closing angle THACLOSE are set. The values ADOPEN and ADCLOSE are subtracted to advance the throttle valve opening timing and the throttle valve closing timing, and a new throttle opening angle THAOPEN and a new throttle closing angle THACLOSE are set (THAOPEN ← THAOPEN−A).
DOPEN, THACLOSE ← THACLOSE−ADCLOSE), and proceeds to step S29.

That is, when the engine operation region is a low-load medium-low rotation region where NOx in the exhaust gas increases,
The throttle opening angle THAOPEN and the throttle closing angle THACLOSE are determined according to the set values ADOPEN and ADCLOSE.
Is advanced, the valve opening period of the throttle valve 14 is relatively advanced. As a result, as shown in FIG. 14 (d), the effective intake period due to the opening period of the throttle valve 14 overlaps with the valve overlap period of the exhaust valve 8 and the intake valve 7, and exhaust from the intake system by this valve overlap. Internal EGR can be performed.
Then, the internal EGR lowers the combustion temperature, and the lowering of the combustion temperature reduces the NOx emission.

In this embodiment, the set values ADOPEN and ADCLOSE for the advance correction of the valve opening timing and the valve closing timing of the throttle valve 14 are respectively set by fixed values, but the engine speed is not changed. The setting may be made according to the engine operating state such as the number NE and the cooling water temperature TW.

In this embodiment, the throttle valve 1
The internal EGR is performed by advancing both the valve opening timing and the valve closing
However, the advance angle may be corrected only for the opening timing of the throttle valve 14.

Then, the process proceeds to a step S29, wherein the throttle valve opening angle THAOPEN is converted into a time to set the valve opening timing TMGOPEN of the throttle valve 14 based on the θ2 crank pulse input. The angle THACLOSE is converted into time, and the closing timing TMGCLOSE of the throttle valve 14 is set based on the θ1 crank pulse input.

In the present embodiment, a so-called time control method is adopted, and a throttle opening timing TMGOPEN for determining the opening timing of the throttle valve 14 and a throttle closing timing TMGCLOSE for determining the closing timing are set by time. I do. That is, since the throttle valve opening angle THAOPEN and the throttle valve closing angle THACLOSE are angle data (crank angle; CA), as shown in FIG. It is converted to the time until the valve 14 is opened, and the throttle closing angle THA
It is necessary to convert CLOSE to the time from when the θ1 crank pulse is input to when the throttle valve 14 is closed.

The latest crank pulse input interval time T obtained by the above-described cylinder discrimination / engine speed calculation routine.
In this embodiment, the throttle valve opening timing TMGOPEN based on the θ2 crank pulse input and the throttle valve closing timing TMGCL based on the θ1 crank pulse input are used.
OSE is set by the following equations.

TMGOPEN ← (Tθ / θ) × THAOPEN TMGCLOSE ← (Tθ / θ) × THACLOSE The cylinder data to be controlled by the throttle valve obtained by the above-described cylinder discrimination / engine speed calculation routine #
i is read, and in step S31, the throttle valve opening timing TMGOPEN of the cylinder #i in the counter / timer group 45 is set to the throttle valve opening timing TMGOPEN. In step S32, the throttle valve of the cylinder #i is closed. The throttle valve closing timing TMGCLOSE is set in the timing timer. And the following step S
At 33, the throttle valve operation prohibition flag FTH is cleared (FTH ← 0), and the routine exits.

As a result, the above-described throttle valve opening timing timer is started by a .theta.2 crank pulse interruption routine shown in FIG. 7, which is started in synchronization with the .theta.2 crank pulse input, and the throttle valve opening timing TMGOPEN
Is reached, the throttle valve 14 of the corresponding cylinder #i is opened and fully opened. Thereafter, the throttle closing timing timer is started by the θ1 crank pulse interruption routine of FIG. 8 which is started in synchronization with the θ1 crank pulse input, and the throttle closing timing TMGCLOS
When the value reaches E, the throttle valve 14 is closed and fully closed.

Thus, for each cylinder, each throttle valve 14 is opened and closed via the throttle actuator 16 in accordance with the opening period of the intake valve 7, and the effective intake period is controlled in accordance with the operating state, and adapted to the operating state. As a result, an accurate engine output can be obtained in the entire operation range.

The intake air amount sensor 28 detects the actual amount of intake air that is taken in by opening and closing each of the throttle valves 14, and the learning routine shown in FIG. Is reflected in the learning value KLR for correcting the opening period of the throttle valve 14 that gives the effective intake period. Then, as described above, the opening period of the throttle valve 14 is corrected by correcting the throttle basic closing angle THACLOSEBASE with the learning correction coefficient KTHLR set based on the learning value KLR. As a result, the intake air amount converges to the target intake air amount, and a deviation of the intake air amount from the target intake air amount due to a variation in production of the intake control system such as the throttle valve 14 and the throttle actuator 16 and deterioration over time, etc. Compensated.

Next, the learning routine of FIG. 5 will be described.

This learning routine is executed at predetermined time intervals after system initialization, and first, steps S41 and S42.
Then, the learning condition is determined.

In step S41, referring to the throttle valve operation prohibition flag FTH, the routine is executed without performing the learning process when the throttle valve 14 is at a fixed throttle opening when FTH = 1 or when the engine stalls or starts, or when the throttle valve 14 is opened due to a system abnormality. Exit.

That is, when the throttle opening is fixed at FTH = 1, the opening / closing control of the throttle valve 14 is stopped. If learning is performed in this state, erroneous learning occurs.
Therefore, at this time, it is determined that the learning condition is not satisfied, and the learning is stopped.

On the other hand, when it is determined that the opening and closing of the throttle valve 14 is normally performed at FTH = 0, the step
In S42, it is determined whether or not the engine operation region is in the engine steady operation state associated with the same region for a predetermined time or more. If the engine operation region is in the transient operation state, the routine exits similarly without performing the learning process.

That is, during a transient operation state in which the engine operation range changes, the intake air amount changes suddenly, and the target intake air amount set based on the engine operation state does not match the actually detected intake air amount. Causes erroneous learning. Therefore, also at this time, the learning condition is not satisfied and the learning is stopped.

If the learning conditions are satisfied in steps S41 and S42 during the throttle valve opening / closing control and the engine is in a steady operation state, the process proceeds to step S43, where the engine speed NE and the accelerator stroke ACS representing the required load are determined. Then, the target intake air amount QATAGT is set by referring to a target intake air amount table composed of a series of addresses in the ROM 42 with interpolation calculation.

As described above, the throttle opening angle THAOPEN and the throttle basic closing angle THACLOSE, which determine the effective intake period by the throttle valve 14, that is, the opening period of the throttle valve 14, are determined by the engine speed NE and the accelerator stroke ACS. Is set based on a target intake air amount QATAGT obtained in advance by simulation or experiment.

Accordingly, in the target intake air amount table, the target intake air amount QATAGT is stored with the engine speed NE and the accelerator stroke ACS as parameters.

One example of the target intake air amount table is shown in step S43. As described above, the engine speed NE
As the load required by the accelerator stroke ACS increases, the target intake air amount QATAGT increases in order to increase the engine output. Therefore, a value corresponding to this is stored in the target intake air amount table.

Then, the process proceeds to a step S44, wherein the actual intake air amount QA detected by the intake air amount sensor 28 is subtracted from the target intake air amount QATAGT to calculate the actual intake air amount QA with respect to the target intake air amount QATAGT. Deviation ΔQA
Is calculated (ΔQA ← QATAGT−QA).

In the following step S45, an address in the learning value table stored in the backup RAM 44 is specified by the current engine speed NE and the accelerator stroke ACS. Then, in step S46, the learning value K stored at the corresponding address in the learning value table is obtained.
LR is read out, and a new learning value KLR is calculated by the following equation based on the learning value KLR and the deviation ΔQA.

KLR ← KLR + M × ΔQA Note that M in the above equation is a coefficient for determining the update ratio of the learning value KLR based on the deviation ΔQA, and is set according to the value of the deviation ΔQA (0 <M <1.0).

Then, the learning value stored at the corresponding address in the learning value table is updated with the newly calculated learning value KLR, and the routine exits.

Incidentally, the initial set value of each learning value KLR stored in the learning value table is KLR = 1.0 (a value without correction). Then, as shown in FIG. 15, a deviation ΔQA of the intake air amount QA with respect to the target intake air amount QATAGT.
Is larger on the plus side, that is, the target intake air amount Q
As the actual intake air amount QA is smaller than ATTAG, the learning value KLR is sequentially increased and updated. Conversely, the deviation ΔQA
Is on the minus side, and as the actual intake air amount QA is larger than the target intake air amount QATAGT, the learning value KLR is sequentially reduced and updated.

Therefore, in the above-described throttle valve opening / closing setting routine, the learning correction coefficient KTHLR set by the learning value KLR together with the interpolation calculation is incorporated into the equation for calculating the throttle valve closing angle THACLOSE which determines the throttle valve closing timing. As a result (see step S22 in FIG. 3), when the actual intake air amount QA is smaller than the target intake air amount QATAGT, the throttle closing angle THACLOSE is corrected by retarding, and the effective intake period by the throttle valve 14 increases. The intake air volume is corrected to increase. When the actual intake air amount QA is larger than the target intake air amount QATAGT, the throttle valve closing angle THACLOSE is advanced and the effective intake period by the throttle valve 14 is reduced, and the intake air amount is corrected to be reduced. .

That is, by the learning feedback control, the intake air amount QA converges to the target intake air amount QATAGT in each operation region, and the production variation and the deterioration with time of the intake control system such as the throttle valve 14 and the throttle actuator 16 are produced. The deviation of the intake air amount from the target intake air amount due to the above factors is compensated. As a result, accurate engine output performance can be obtained in each operating region.

As described above, in the present embodiment, in order to set the fuel injection amount by the L jetronic method, the intake air amount sensor 28 is provided, and the intake air amount sensor 28 Can be detected directly. On the other hand, when the D jetronic method is adopted, the intake pipe pressure downstream of the throttle valve 14 is detected by an intake pipe pressure sensor, and the intake air amount QA is indirectly determined based on the intake pipe pressure and the engine speed NE. The present invention can be applied to the D-Jetronic method, and the above-described learning control can be applied.

Further, since the throttle valve 14 opens and closes in response to the opening and closing of the intake valve 7, the fluctuation of the intake pipe pressure downstream of the throttle valve 14 is large. Therefore, when applying to the D JETRONIC system, it is desirable to average the intake pipe pressure and to use this average intake pipe pressure as a parameter.

On the other hand, the cylinder deactivation control flag FCYL in the above-described throttle valve opening / closing control routine is referred to in the cylinder deactivation control routine of FIG. 6 which is executed at predetermined time intervals. Cylinder deactivation control for deactivating is performed.

Next, the cylinder deactivation control routine of FIG. 6 will be described.

In this cylinder deactivation control routine, first, in step S51, the cylinder deactivation control flag FCYL is referred to, and
It is determined whether or not the cylinder deactivation control is instructed. If FCYL = 0 and the cylinder deactivation control is not instructed, the process proceeds to step S52, where the initial discrimination flag FINI for determining the first execution of the cylinder deactivation control is cleared (FINI
← 0), the routine exits without performing the cylinder deactivation control.

On the other hand, in the above step S51, FCYL = 1
If the operating state is in the cylinder-stop region (idle, extremely low load, idle idling, maximum vehicle speed limit, etc.), and cylinder stop control is instructed, the process proceeds to step S53, and the initial determination flag FINI is referred to. I do.

When FINI = 0 and the first routine is executed after the transition to the cylinder deactivation control, the process proceeds to step S54,
The first discrimination flag FINI is set (FINI ← 1), and in step S55, cylinders to be deactivated (rest cylinders) # N1 and # N2.
To select # 1 cylinder and # 4 cylinder (# N1 ← #
1, # N2 ← # 4), and the process proceeds to step S56.

That is, in the present embodiment, # 1, # 4
Cylinders and # 2 and # 3 cylinders are grouped.
Stop fuel injection and ignition of the # 4 cylinder and deactivate the cylinder.
Thereafter, the cylinders # 1 and # 4 and the cylinders # 2 and # 3 are alternately deactivated at predetermined intervals.

Then, in step S56, the group change time count value CCYL for counting the time for alternately changing the idle cylinder group at predetermined intervals is cleared (CC
YL ← 0), and in subsequent steps S57 and S58, the valve-opening excitation coil 16c of the throttle actuator 16 of the currently selected inactive cylinder group # N1, # N2, ie, # 1, # 4 cylinder, is turned on and the valve is closed. Excitation coil 16d to O
FF and exit the routine.

As a result, when shifting to the cylinder deactivation control, the cylinders # 1 and # 4 are first deactivated by stopping the fuel injection and ignition, and the throttle valves 1 of the # 1 and # 4 cylinders are deactivated.
4 is fully opened.

Then, at the time of executing the second and subsequent routines after the transition to the cylinder deactivation control, the initial discrimination flag FINI is set in step S54 described above (FINI =
1) The process proceeds from step S53 to step S59.

In step S59, the group change time count value CCYL is counted up (CCYL ← CCYL +
1) In a succeeding step S60, the group change time count value CCYL is compared with a set value CS1 which determines a change cycle of the deactivated cylinder group. If CCYL <CS1 and the group change time count value CCYL has not reached the predetermined time determined by the set value CS1, the routine exits from the routine and continues the deactivation of the currently selected deactivated cylinder group.

Thereafter, in step S60, CCYL
When ≧ CS1, and the group change time count value CCYL reaches a predetermined time determined by the set value CS1, the process proceeds to step S61, where the currently selected deactivated cylinder group #
It is determined whether N1 and # N2 are # 1 and # 4 cylinders.

When the currently selected deactivated cylinder groups # N1 and # N2 are the # 1 and # 4 cylinders (#N
1, # N2 = # 1, # 4), the process proceeds to step S62, and # 2 cylinder and # 3 cylinder are selected as the cylinders # N1, # N2 (# N1 ← # 2, # N2 ← # 3). Proceeding to step S56, clear the group change time count value CCYL,
After steps S57 and S58, the valve-opening excitation coil 16c of the throttle actuator 16 of the selected deactivated cylinder group # N1, # N2, that is, the cylinder # 2, # 3, is turned on and the valve-closing excitation coil 16d is turned off. And exit the routine.

Therefore, after the cylinders of the # 1 and # 4 cylinders are deactivated, the deactivated cylinder group is changed to the # 2 and # 3 cylinders when the predetermined time based on the set value CS1 has been reached.

As a result, the cylinders # 2 and # 3 are stopped by stopping the fuel injection and ignition, and the throttle valves 14 of the # 2 and # 3 cylinders are fully opened. Further, in synchronization with this, fuel injection and ignition of the # 1 and # 4 cylinders are restarted, and the # 1 crank pulse interrupt routine of FIG. 7 and the θ1 crank pulse interrupt routine of FIG. The opening and closing of the throttle valve 14 of the # 4 cylinder is restarted.

On the other hand, in step S61, the currently selected deactivated cylinder groups # N1 and # N2 are
When # 1, # N2 ≠ # 1, # 4, that is, when the cylinders are # 2, # 3, the process proceeds to step S55, and the cylinders # N1, # N2 are closed.
And select # 1 cylinder and # 4 cylinder
After S56 to S58, the process exits the routine.

Therefore, during the execution of the cylinder deactivation control, the deactivated cylinders are set to # 1 and # 4 every predetermined cycle based on the set value CS1.
The cylinders are alternately changed to # 2 and # 3 cylinders.

Since the throttle valve 14 is fully opened in the idle cylinder, the pumping loss caused by the unnecessary expansion and compression of the air in the idle cylinder can be reduced, and the fuel efficiency can be improved. .

Further, the deactivated cylinders are set to # 1,
Since it is alternately changed to # 4 cylinder and # 2, # 3 cylinder,
It becomes possible to prevent the spark plug 21 of the idle cylinder from being stained by fixing the idle cylinder, thereby preventing deterioration of ignitability. In addition, a decrease in the temperature of the deactivated cylinder due to the deactivated cylinder being fixed prevents deterioration of the flammability of the cylinder when the deactivation of the cylinder is canceled, and prevents combustion fluctuation between the cylinders due to temperature variation between the cylinders. It is possible to do.

Further, 1 is set in the combustion order so that the combustion is performed at regular intervals.
Since the cylinders are grouped for each cylinder and the deactivated cylinders are changed at predetermined intervals, it is possible to prevent engine rotation fluctuations due to variations in the combustion intervals when the cylinders are deactivated.

In this embodiment, the fuel injection and the fuel supply to the idle cylinder are stopped. However, for the idle cylinder, the cylinder is stopped if at least the fuel injection to the cylinder is stopped. Therefore, at least the fuel injection to the cylinder may be stopped, and the ignition may be continued.

Next, the respective routines shown in FIGS. 7 to 10 for performing the processing for operating the throttle valve opening timing timer and the throttle closing timing timer and the processing for opening and closing each throttle valve 14 will be described.

The .theta.2 crank pulse interruption routine shown in FIG. 7 starts in synchronization with the .theta.2 crank pulse input, and refers to the throttle valve operation inhibition flag FTH and the cylinder deactivation control flag FCYL in steps S71 and S72, respectively.

Then, when the system is normal at FTH = 0 and during normal operation after the complete combustion of the engine, and when FCYL = 0, no cylinder deactivation control is instructed and the operation region is outside the cylinder deactivation region, The process jumps to step S74, starts the throttle valve opening timing timer of the cylinder #i to be controlled, and exits the routine.

When the throttle valve opening timing timer reaches the throttle valve opening timing TMGOPEN, the routine shown in FIG. 9 is started by interruption. In step S91, the throttle actuator 1 of the corresponding cylinder #i is started.
6, the valve opening excitation coil 16c is turned on, and in step S92, the valve closing excitation coil 16d of the throttle actuator 16 is turned off, and the throttle valve 16 of the corresponding cylinder #i is opened and fully opened (FIG. 12).

Thereafter, when the θ1 crank pulse is input, the θ1 crank pulse interrupt routine shown in FIG. 8 is started in synchronization with the input, and in steps S81 and S82, the throttle valve operation prohibition flag FTH and the cylinder deactivation control flag FCYL, respectively. See

Since both the flags FTH and FCYL are cleared, the system is normal, the engine is in normal operation after the complete explosion, and the cylinder deactivation control is not instructed, and the operation region is in the cylinder stop region. If not, the process jumps to step S84, starts the throttle closing timing timer of the cylinder #i, and exits the routine.

As a result, the throttle closing timing TMGCLOSE is determined by the timing of the throttle closing timing timer.
10, the routine shown in FIG. 10 is started by interruption. In step S101, the valve opening excitation coil 16c of the throttle actuator 16 of the corresponding cylinder #i is turned off, and in step S102, the throttle actuator 16 is turned off. The valve closing excitation coil 16d is turned on, and the corresponding cylinder #
The i-th throttle valve 16 is closed and fully closed (see FIG. 12).

Therefore, when the system is normal and during normal operation after the complete combustion of the engine, and when the cylinder deactivation control is not instructed and the operation region is outside the cylinder deactivation region, as shown in FIG. For each cylinder, each throttle valve 14 is opened and closed via the throttle actuator 16 in accordance with the valve opening period of the intake valve 7, and the effective intake period is optimally controlled in accordance with the operating state. That is, the conventional conventional valve operating mechanism is adopted, and the cylinder opening period (valve timing) by the intake valve 7 is not controlled, and each cylinder is separately operated.
The effective intake period can be continuously controlled in accordance with the operation state, and an accurate engine output can be obtained in the entire operation range according to the operation state, and the engine output can be improved.

Further, the effective intake period can be controlled only by controlling the opening / closing timing of the throttle valve 14, and a complicated and high-cost mechanism such as a variable valve timing mechanism is not required. It is possible to do.

Further, the effective intake period can be continuously varied according to the operation state, and if the sealability of the throttle valve 14 can be ensured to some extent, the pump loss in the intake stroke is reduced, and the fuel efficiency at the partial load is reduced. Improvement can be achieved.

Also, by independently providing the throttle valve 14 for each cylinder, that is, by using a so-called independent throttle,
Since the intake resistance of the throttle valve 14 is reduced, it is possible to improve the full load maximum output.

Further, the throttle valve 14 which is required to easily seal the intake valve 7 is used. As described above, the throttle actuator 16 uses the battery voltage because the electric energy required to drive the throttle valve 14 is small. And the throttle valve 14 can operate stably even when the battery voltage decreases. Further, since the throttle actuator 16 is provided alongside the intake manifold 9 having good thermal environmental conditions, the effect of electromagnetic performance deterioration due to high temperature is small, and the operation reliability is high. Therefore, the intake period can be appropriately controlled for each cylinder, and control reliability can be improved.

Further, in an internal EGR region such as a low-load medium-low rotation region where NOx in the exhaust gas increases, the opening period of the throttle valve 14 is relatively advanced, thereby opening the throttle valve 14. The effective intake period due to the valve period overlaps with the valve overlap period of the exhaust valve 8 and the intake valve 7, and the internal EGR is performed by this valve overlap, so that the NOx emission can be reduced by lowering the combustion temperature. Become. That is, since the internal EGR can be controlled only by controlling the opening / closing timing of the throttle valve 14, a complicated and expensive mechanism for continuously and variably controlling the phase of the intake cam 5a or the opening period of the intake valve 7 is provided. Is unnecessary, and the control speed can be dramatically improved. Further, the present invention can be realized without employing an external EGR system, and contamination of the intake system by EGR gas can be prevented.

On the other hand, when FTH = 1 and the throttle valve operation prohibition flag HTH is set, the routine proceeds from step S71 in the θ2 crank pulse interrupt routine of FIG. 7 to the above-described routine in the θ1 crank pulse interrupt routine of FIG. From step S81, the process exits the routine.

Therefore, when the engine stops at FTH = 1 or when the engine is started, or when the intake control system (throttle valve control system) is abnormal, the routine immediately exits the routine in each of the crank pulse interrupt routines. Double excitation coil 1
6c and 16d are both kept OFF, and the throttle valves 14 of all cylinders are maintained at a fixed throttle opening.

In the normal operation of the system with FTH = 0 and normal operation after the complete combustion of the engine, if FCYL = 1 and the cylinder deactivation control is instructed, the above-mentioned θ2 crank pulse interruption routine in FIG. Step S7
After step S72, the process proceeds to step S73.
In the crank pulse interrupt routine, step S8
The process proceeds to step S83 via steps 1 and S82, and steps S73 and S83 are performed.
, It is determined whether or not the cylinder #i to be controlled by the throttle valve is the currently selected deactivated cylinder group # N1, # N2.

When the corresponding cylinder #i is selected as a deactivated cylinder group (# i = # N1 or #N
2) Exit the routine.

In each of the above steps S73 and S83,
When the corresponding cylinder #i is not a paused cylinder group (#i
(# N1 or # N2), through the above steps S74 and S84, the throttle valve opening timing timer and the throttle valve closing timer of the cylinder #i to be controlled are started, and the routine exits.

Therefore, at the time of the cylinder deactivation control, for the deactivated cylinder group currently selected by the above-described cylinder deactivation control routine of FIG.
By exiting the routine as it is, the valve opening excitation coil 1 of each throttle actuator 16 of the idle cylinder group is opened.
6c is kept ON and the valve closing excitation coil 16d is kept OFF.
Is kept fully open.

At this time, for the cylinders outside the idle cylinder group, the operation of each timer causes the throttle valve 14 to be opened and closed in accordance with the opening period of the intake valve 7 and the effective intake according to the operating state. The period is controlled optimally.

Next, a second embodiment of the present invention will be described with reference to FIGS.

The present embodiment is different from the first embodiment in that a bypass passage bypassing each throttle valve 14 and connected to an intake passage, and an idle speed control provided in the bypass passage are further provided. And a valve. During extremely low load operation, the throttle valves of all cylinders are fully closed, and the amount of intake air is controlled by the idle speed control valve.

That is, when the effective intake period is controlled by the throttle valve 14, the required output is small and the opening period of the throttle valve 14 becomes very short during an extremely low load operation such as idling. Is required to have high sealing properties. Also, if there is a variation in the sealability of the throttle valve 14 between the cylinders, a variation in the in-cylinder intake air amount will occur for each cylinder at the time of idling, and the combustion state will differ between the cylinders. As a result, the engine speed fluctuates, and the idle speed becomes unstable.
For this reason, when the effective intake period is controlled by the throttle valve 14 in the entire operation range, the accuracy required for the throttle valve 14 is extremely high, which leads to an increase in cost. There is a problem in the controllability of the intake air flow rate of the fuel cell.

Therefore, during an extremely low load operation including the idling time when the sealing property of the throttle valve 14 becomes a problem, the throttle valves 14 of all the cylinders are fully closed and the control of the effective intake period by opening and closing the throttle valve 14 is stopped. By controlling the intake air amount by the idle speed control valve, the idle speed controllability and the intake air amount controllability under extremely low load are improved.

Also, only in the operation state except for the extremely low load where the sealing performance of the throttle valve 14 is not required to be relatively high, each cylinder is controlled via the throttle actuator 16 in correspondence with the opening period of the intake valve 7 for each cylinder. The throttle valve 14 is opened and closed to control the effective intake period.

Specifically, the present embodiment is different from the above-described FIG.
As shown by a two-dot chain line in FIG. 6 and FIG. 17, a bypass passage 60 that bypasses each throttle valve 14 and that connects the intake pipe 11 and the intake manifold 9 of each cylinder downstream of the throttle valve 14 is provided as an intake passage. . The idle speed control valve (I
SC valve) 61 is provided.

As shown by the two-dot chain line in FIG.
The ISC valve 61 is connected to an output port of the I / O interface 46 of the CU 40 via a drive circuit 48.

The ISC valve 61 is controlled by the ECU 40. In this embodiment, as the duty ratio of the drive signal output from the ECU 40 increases, the valve opening increases to increase the intake air flow rate. As the duty ratio decreases, the valve opening decreases and the intake air flow rate decreases.

Then, in the ECU 40, based on the accelerator stroke ACS, the idling operation (ACS =
(0; accelerator pedal released state). During the extremely low load operation, the throttle valves 14 of all the cylinders are fully closed and the ISC valve 61 controls the amount of intake air. On the other hand, in the operating state except for the extremely low load, the opening timing TMGOPEN and the closing timing TMGCLOSE of each throttle valve 14 are set for each cylinder based on the engine operating state, as in the first embodiment. The valve opening timing TMGOPEN and the valve closing timing TMGCLOSE
Accordingly, each throttle valve 14 is controlled via the throttle actuator 16 in accordance with the opening period of the intake valve 7 for each cylinder.
By opening and closing, the effective intake period is controlled.

That is, in the present embodiment, the ECU 40 realizes a function as an extremely low load determining means and a control means according to the third aspect of the present invention.

In this embodiment, a throttle valve opening / closing timing setting routine shown in FIGS. 24 to 25 is employed instead of the throttle valve opening / closing timing setting routine of FIG. 3 in the first embodiment.

The latter half of the throttle valve opening / closing timing setting routine and other routines are the same as in the first embodiment, and a description thereof will be omitted. Also,
In the throttle valve opening / closing timing setting routines of FIGS. 24 and 25, the same steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Hereinafter, the throttle valve opening / closing timing setting routine shown in FIGS. 24 and 25 will be described.

The throttle valve opening / closing timing setting routine shown in FIGS. 24 and 25 is executed at predetermined intervals after system initialization, as in the first embodiment. First, in steps S11 and S12, an engine start determination is made. Do.

Then, the starter switch 39 is turned on, or the engine speed NE falls below the complete explosion speed NESET,
When it is determined that the engine has been started or stopped, the process proceeds from the corresponding step to step S201, where the ISC valve 61 at the time of engine stall or startup is referred to by referring to the starting characteristic value table based on the coolant temperature TW representing the engine temperature.
The duty ratio DUTY which determines the control amount with respect to is set.

The starting characteristic value table shows that the ISC valve 61 for obtaining the appropriate opening degree of the ISC valve 61 in preparation for the engine operation for each region based on the coolant temperature TW representing the engine temperature.
The duty ratio DUTY of the drive signal with respect to is obtained in advance by simulation or experiment and stored in a series of addresses in the ROM 42.

An example of the starting characteristic value table is shown in step S201. As shown in step S201, when the cooling water temperature TW is low and the engine is cold, the valve opening of the ISC valve 61 is increased, and the ISC
A high value of the duty ratio DUTY is stored in order to increase the idle speed by increasing the intake air flow rate by the valve 61 to prevent the combustion performance from deteriorating and to promote the warm-up of the engine 1. Further, as the cooling water temperature TW increases, I
The opening degree of the SC valve 61 is reduced to reduce the idle speed after the shift to the engine operation. In the normal temperature range where the engine warm-up is completed, a low idle speed is obtained for the purpose of reducing engine noise and improving fuel efficiency. The duty ratio DUTY is stored.

In step S202, the duty ratio DUTY is set. In steps S203 and S204, the valve opening excitation coil 16c of the throttle actuator 16 for all cylinders is turned off and the valve closing excitation coil 16d is set.
Is turned on, and the routine jumps to step S15. Then, in step S15, the throttle valve operation prohibition flag FTH is set, and in step S16, the cylinder deactivation control flag FCYL is cleared, and the routine exits.

As a result, when the engine stalls or the engine is started, the throttle valves 14 of all the cylinders are fully closed and the drive signal of the duty ratio DUTY is transmitted to the ECU 40.
Is output to the ISC valve 61 to prepare for engine operation.
The valve opening of the ISC valve 61 is maintained at an appropriate value according to the engine temperature.

In steps S11 and S12, on the other hand, the starter switch 39 is turned off and the engine speed NE is set.
When the engine speed is equal to or higher than the complete explosion rotational speed NESET and the engine is in normal operation after the complete explosion, the process proceeds to step S206, and it is determined whether or not the current operation state is an extremely low load operation such as idle. This determination is made, for example, by the accelerator stroke A by the accelerator sensor 37.
CS is compared with a predetermined value, and when the accelerator stroke ACS is equal to or less than the predetermined value, it can be determined that the operation is extremely low load.

At the time of extremely low load operation including idling, the routine proceeds to step S206, where the basic characteristic value table is referenced with interpolation calculation based on the accelerator stroke ACS and the engine speed NE indicating the required load, and the extremely low load operation is performed. A basic duty ratio DUTYBASE that determines a basic control amount for the ISC valve 61 suitable for operation is set.

The above-mentioned basic characteristic value table shows that an appropriate engine output for obtaining a target engine output at the time of extremely low load operation is obtained by a simulation or an experiment in advance for each region based on the accelerator stroke ACS indicating the required load and the engine speed NE. A target intake air amount is obtained, and a valve opening of the ISC valve 61 that is appropriate for obtaining the target intake air amount is obtained. The duty ratio DUTY of the drive signal for the ISC valve 61 that obtains the appropriate valve opening is determined by the basic duty. Ratio DUTY
BASE is stored in a series of addresses in the ROM 42.

One example of the basic characteristic value table is shown in step S206. As shown in step S206, as the accelerator stroke ACS is smaller and the engine speed NE is lower, the required engine output is lower. Therefore, the opening degree of the ISC valve 61 is reduced, and the intake air flow rate of the ISC valve 61 is reduced. To reduce the basic duty ratio D
UTY is stored. Also, accelerator stroke A
As CS increases and engine speed NE increases,
The required engine output increases, so that the basic duty ratio D of a large value is increased in order to increase the valve opening by the ISC valve 61 and increase the intake air flow rate by the ISC valve 61.
UTY is stored.

At the following step S207, the cooling water temperature sensor 3
1, the basic duty ratio D according to the engine warm-up state by referring to the table based on the cooling water temperature TW by
A water temperature correction coefficient KTWISC for correcting UTYBASE is set.

The water temperature correction coefficient KTWISC is used to increase the valve opening degree of the ISC valve 61 and increase the intake air flow rate when the engine temperature is low, according to the engine coolant temperature TW, that is, the engine warm-up state. It is for raising the engine warm-up.

As shown in step S207, when the engine coolant temperature TW is low, the table
A large water temperature correction coefficient KTWISC is stored to increase the valve opening of the valve 61 and increase the idle speed. Then, the water temperature correction coefficient KTWISC is decreased according to the rise of the engine cooling water temperature TW, and KTW = 1.0 when the engine warm-up is completed, and there is no correction by the water temperature correction coefficient.

Then, in step S208, the basic duty ratio DUTYBASE is multiplied by the water temperature correction coefficient KTWISC to correct the water temperature, and a duty ratio DUTY that determines a control amount for the ISC valve 61 is set (DUTY ← DUT).
YBASE × KTWISC).

[0221] At idle, the cooling water temperature T
A target rotation speed may be set based on W or the like, and the duty ratio DUTY may be feedback-corrected according to a result of comparison between the target rotation speed and the engine rotation speed NE.

Then, proceeding to step S202, the duty ratio DUTY set in step S208 is set, and through steps S203 and S204, the valve opening excitation coil 16c of the throttle actuator 16 of all cylinders is turned off and closed. The valve excitation coil 16d is turned on. And
Further, through steps S15 and S16, the throttle valve operation prohibition flag FTH is set, the cylinder deactivation control flag FCYL is cleared, and the routine exits.

As a result, during extremely low load operation, the throttle valves 14 of all cylinders are fully closed and the intake air amount control by the ISC valve 61 becomes possible. Then, a drive signal of the duty ratio DUTY is output from the ECU 40 to the ISC valve 61, and the valve opening of the ISC valve 61 is controlled so as to obtain a target intake air amount suitable for extremely low load operation.

Therefore, during an extremely low load operation including an idling time when the sealing property of the throttle valve 14 becomes a problem, the throttle valves 14 of all the cylinders are fully closed and the control of the effective intake period by opening and closing the throttle valve 14 is stopped. In addition, since the intake air amount is controlled by the ISC valve 61, the controllability of the idle speed and the controllability of the intake air amount under an extremely low load are improved. Also, at idle when the background noise is low, the throttle valve 1
Since the opening / closing of the throttle valve 4 is stopped, the operation noise caused by the throttle valve 14 can be eliminated.

On the other hand, in step S205, in the operation state except for the extremely low load, the routine proceeds to step S209, where the duty ratio DUTY is set to 0%, and this duty ratio DU is set.
TY is set in step S210.

As a result, in the operation state except for the extremely low load, the effective intake period is controlled by fully closing the ISC valve 61 and opening and closing each throttle valve 14 in accordance with the opening period of the intake valve 7. It becomes possible.

Then, the process proceeds to a step S17, wherein an abnormality of the intake control system (throttle valve control system) is determined, and
If the system is abnormal, proceed to step S13 and proceed to step S1.
3. At S14, the opening coil 16c and the closing coil 16d of the throttle actuators 16 of all cylinders are turned off.
F, and the process exits the routine through steps S15 and S16.

Therefore, when the intake control system (throttle valve control system) is abnormal and in an operation state except for a very low load, both of the excitation coils 16c and 16d of each throttle actuator 16 are turned off. As in the first embodiment, the throttle valves 14 of all the cylinders have a fixed throttle opening (see FIG. 14C).

As a result, in the operating region in which intake control is performed by opening and closing the throttle valve 14, a sensor for detecting parameters related to throttle valve control, the throttle actuator 16, and the like are abnormal, and an abnormality has occurred in the intake control system. However, the minimum required vehicle traveling is ensured.

On the other hand, when the system is normal in step S17, the process proceeds to step S18, and by the processing after step S18, the opening of each throttle valve 14 for each cylinder based on the engine operating state is performed as in the first embodiment. Set the valve timing TMGOPEN and the valve closing timing TMGCLOSE. The valve opening timing TMGOPEN and the valve closing timing TMGCLOS
In accordance with E, each throttle valve 1 is controlled via the throttle actuator 16 in accordance with the opening period of the intake valve 7 for each cylinder.
By opening and closing 4, the effective intake period is controlled.

Next, a third embodiment of the present invention will be described with reference to FIG.

In each of the above embodiments, the intake air amount sensor 28 or the intake pipe pressure sensor (not shown) is provided to set the fuel injection amount by the L jetronic system or the D jetronic system. The actual intake air amount QA is detected by these sensors, and the deviation ΔQ of the actual intake air amount QA from the target intake air amount QATAGT is detected.
According to A, the learning value KLR for correcting the valve opening period of the throttle valve 14 that gives the effective intake period can be learned.

However, based on the accelerator stroke ACS representing the required load and the engine speed NE, a so-called α
In the case of an engine that sets the fuel injection amount by the -N method, the engine does not include the intake air amount sensor or the intake pipe pressure sensor, and cannot detect the actual intake air amount.

Therefore, the present embodiment detects the actual intake air amount in an engine in which the fuel injection amount is set by the so-called α-N method based on the accelerator stroke ACS indicating the required load and the engine speed NE. A learning value KLR for correcting the opening period of the throttle valve 14, which gives the effective intake period, can be learned even if no sensor is provided.

That is, in the present embodiment, as an example of the O2 sensor 32 for detecting the air-fuel ratio, a linear O2 sensor having an output characteristic linear with respect to the air-fuel ratio (hereinafter, the same reference numeral as the O2 sensor 32 is used) ).
When a fuel injection amount is set in a fuel injection amount setting routine (not shown) or the like, a target air-fuel ratio set according to the engine operating state is used.
2 The deviation Δ between the target intake air amount and the actual intake air amount based on the difference between the actual air-fuel ratio detected by the sensor 32
Estimate QA. Then, the learning value KLR is learned based on the deviation ΔQA, and the opening period of the throttle valve 14 can be learned and corrected.

Specifically, in the present embodiment, the learning routine shown in FIG.
The learning routine shown in FIG.

Note that the other routines are the same as those in the above-described embodiments, and a description thereof will be omitted. In the learning routine of FIG. 26, the same steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The learning routine of FIG. 26 will be described below.

The learning routine shown in FIG. 26 is executed at predetermined time intervals after system initialization, as in the first embodiment, and the learning conditions are determined in steps S41 and S42.

The throttle valve operation inhibition flag FTH
Is set (FTH = 1), and when the opening / closing control of the throttle valve 14 is stopped or in the transient operation state, the routine exits from the corresponding step without performing the learning process.

When the throttle valve opening / closing control is being performed and the engine is in the steady operation state, the flow proceeds to step S301, where the engine speed NE and the accelerator stroke A representing the required load are set.
Correction coefficient KQA based on CS and referring to table
Set.

This correction correction coefficient KQA is determined by the target air-fuel ratio A / FTAGT and the linear
2 To estimate and set the deviation ΔQA between the target intake air amount and the actual intake air amount by correcting the difference (A / FTAGT−A / F) from the actual air-fuel ratio A / F detected by the sensor 32. belongs to.

Here, when the actual intake air amount is larger than the target intake air amount, the actual air-fuel ratio A / F becomes a lean air-fuel ratio with respect to the target air-fuel ratio A / FTAGT (A / FTAGT <
A / F), and when the actual intake air amount is smaller than the target intake air amount, the actual air-fuel ratio A / F becomes a rich air-fuel ratio with respect to the target air-fuel ratio A / FTAGT (A / FTAGT> A).
/ F). Therefore, the difference between the target air-fuel ratio A / FTAGT and the actual air-fuel ratio A / F (A / FTAGT-A / F) corresponds to the deviation ΔQA between the target intake air amount and the actual intake air amount.

However, even if the difference (A / FTAGT-A / F) between the target air-fuel ratio A / FTAGT and the actually detected air-fuel ratio is the same, the target intake air amount and the actual Are different from the intake air amount ΔQA.

That is, as the required load due to the accelerator stroke ACS is higher and the engine speed NE is higher, the required intake air amount increases, and the deviation ΔQA between the target intake air amount and the actual intake air amount becomes relatively large. growing.

Therefore, in order to accurately estimate the deviation ΔQA between the target intake air amount and the actual intake air amount, the target air-fuel ratio A
/ FTAGT and actual air-fuel ratio difference (A / FTAGT-A / F)
Needs to be corrected according to the engine operating state.

For this reason, the above table shows the difference (A / FTAGT-A / F) between the target air-fuel ratio A / FTAGT and the actual air-fuel ratio for each region based on the accelerator stroke ACS indicating the required load and the engine speed NE. Is corrected, and a correction correction coefficient KQA appropriate for estimating the deviation ΔQA between the target intake air amount and the actual intake air amount is obtained in advance by simulation or experiment, and stored in a series of addresses in the ROM 42.

An example of this table is shown in step S301. As described above, even if the difference (A / FTAGT-A / F) between the target air-fuel ratio A / FTAGT and the actual air-fuel ratio A / F is the same, the load required by the accelerator stroke ACS is high, and the engine speed is increased. The higher the NE, the larger the deviation ΔQA between the target intake air amount and the actual intake air amount becomes. Therefore, as shown in step S301, the correction correction coefficient KQA having a smaller value is stored in the table as the accelerator stroke ACS is smaller and the engine speed NE is lower, and the accelerator stroke ACS is increased. As the engine speed NE increases, a larger correction correction coefficient KQA is stored.

Next, the routine proceeds to step S302, in which a target air-fuel ratio A / FTAGT which is set according to the engine operating state when setting the fuel injection amount in a fuel injection amount setting routine (not shown) is read out. A / FTAGT and actual air-fuel ratio A detected by linear O2 sensor 32
/ F (A / FTAGT-A / F) is calculated. The difference (A / FTAGT-A / F) between the target air-fuel ratio A / FTAGT and the actual air-fuel ratio A / F is calculated by the correction correction coefficient KQA.
, A deviation ΔQA between the target intake air amount and the actual intake air amount is estimated and set (ΔQA ← KQA × (A /
FTAGT-A / F)).

In step S45, the address in the learning value table is specified by the current engine speed NE and the accelerator stroke ACS. Then, step S4
In step 6, the learning value KLR stored in the corresponding address of the learning value table is read, and a new learning value KLR is calculated based on the learning value KLR and the deviation ΔQA (KLR ← K
LR + M × ΔQA), the learning value stored at the corresponding address in the learning value table is updated with the newly calculated learning value KLR, and the routine exits.

In the throttle valve opening / closing timing setting routine of each of the above-described embodiments, the learning correction coefficient KTHLR calculated by interpolation using the learning value KLR is used to calculate the throttle opening angle which determines the throttle opening timing. (Step S22 in FIG. 3 or FIG. 25)
Reference), the effective intake period by the throttle valve 14 is controlled so that the actual intake air amount converges to the target intake air amount.

Note that the learning processing according to the present embodiment uses α-
It is intended for an engine that sets the fuel injection amount according to the N method, but is not limited to this.
Alternatively, the present invention can be applied to an engine in which the fuel injection amount is set by the D-Jetronic method.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.

In each of the above embodiments, the throttle actuator 16 is individually provided for each cylinder and each throttle valve 14 is operated. On the other hand, in this embodiment, the opening period of the intake valve 7 is limited. A plurality of non-overlapping cylinders are grouped into one group, and throttle actuators 16 are provided corresponding to the number of cylinder groups, and the throttle valves 14 in this cylinder group are collectively driven.

More specifically, in the present embodiment, as shown in FIG. 27, as cylinder groups in which the opening periods of the intake valves 7 do not overlap, every other cylinder in combustion order, # 1 cylinder and # 4 cylinder , And a cylinder group of # 2 cylinder and # 3 cylinder, and throttle actuators 16A and 16B are arranged corresponding to the cylinder group.

As shown in the time chart of FIG. 28, the throttle valve 14 of the # 1 cylinder and the throttle valve 14 of the # 4 cylinder are simultaneously opened and closed by the throttle actuator 16A, and the throttle valve of the # 2 cylinder is opened and closed by the throttle actuator 16B. The valve 14 and the throttle valve 14 of the # 3 cylinder are simultaneously opened and closed.

That is, for a cylinder in which the intake valve 7 is closed, opening or closing the throttle valve 14 during the valve closing period has no effect, and therefore, a plurality of cylinders in which the valve opening periods of the intake valve 7 do not overlap. Even if each throttle valve 14 of a cylinder is opened and closed simultaneously by a single throttle actuator, it is possible to individually control the effective intake period of each cylinder.

As a result, the required number of throttle actuators can be reduced, and the cost can be reduced.

In this case, in each of the above embodiments, a throttle valve opening timing timer and a throttle valve closing timing timer are provided for each cylinder group. The opening and closing of the valve 14 may be controlled.

In response to this, if the fuel injection and ignition are changed from cylinder-based control to cylinder-group-based control, the need for the cam rotor 35 and the cylinder discrimination sensor 36 for discriminating the cylinders is eliminated, and the cost is further reduced. It is possible to do.

In each of the above embodiments, a so-called time control method is adopted as the opening / closing control of the throttle valve 14. However, the present invention is not limited to this. It goes without saying that an angle control method of directly controlling may be adopted.

[0262]

As described above, according to the first aspect of the present invention, an intake control valve for opening and closing an intake passage is provided for each cylinder immediately upstream of the intake valve of each cylinder. Control valve driving means for opening and closing the valve is provided. Then, an opening period of the intake control valve within the opening / closing period of the intake valve is set based on the engine operating state, and each intake control is performed via a control valve driving unit for each cylinder based on the opening period of the intake control valve. Since the valve opens and closes to control the intake period, it is possible to use a conventional conventional valve operating mechanism, and to have the same function as the variable valve timing device without controlling the valve opening period (valve timing) of the intake valve. it can. Further, it is possible to continuously control the intake period for each cylinder in accordance with the operation state, so that an accurate engine output can be obtained in the entire operation range, and the engine output can be improved.

Further, the sealing performance of the intake control valve required when the intake control valve is fully closed is sufficiently lower than the sealing performance of the intake valve. Therefore, the energy required for driving the intake control valve in the control valve driving means is small, and a stable operation can be always obtained. Further, the control valve driving means can be provided in the intake system of the engine having good thermal environment conditions, and is less affected by electromagnetic performance deterioration due to high temperature, and can achieve high operation reliability.

Therefore, the intake period can be appropriately controlled for each cylinder, and the control reliability can be improved.

According to the second aspect of the present invention, the intake control valves of all cylinders are fixed at a predetermined opening when the engine stalls or when the engine is started. By stopping the opening and closing control of the throttle valve, useless control can be prevented. In addition, at this time, the intake control valves of all cylinders are fixed at a predetermined opening degree. Therefore, even if the operation shifts to the start of the engine, the intake air is secured and the start of the engine can be prevented from being hindered. Also, when the engine is started, the power supply voltage to the intake control valve driving means is unstable, so at this time, the opening / closing control of the intake control valves of all cylinders is stopped and the intake control valves of all cylinders are set to the predetermined opening degree. It has an effect that it can be fixed to ensure proper engine startability.

According to the third aspect of the present invention, an intake control valve for opening and closing an intake passage is provided for each cylinder immediately upstream of the intake valve for each cylinder, and a control valve for opening and closing each intake control valve is provided. The air conditioner further includes a driving means, and further includes a bypass passage bypassing the intake control valve and connected to the intake passage, and an idle speed control valve disposed in the bypass passage. And
It is determined whether or not the operation is an extremely low load operation. When the operation is an extremely low load operation, the intake control valves of all cylinders are fully closed and the amount of intake air is controlled by the idle speed control valve. On the other hand, in the operation state except the extremely low load, the opening period of the intake control valve within the opening period of the intake valve is set based on the engine operation state, and by the opening period of the intake control valve, for each cylinder, Since each intake control valve is opened and closed via the control valve driving means to control the intake period, during extremely low load operation, the intake control valves of all cylinders are fully closed, and the intake air amount can be controlled by the idle speed control valve. Becomes Therefore, in addition to the effect of the first aspect of the present invention, during extremely low load operation including idling when the sealing performance of the intake control valve is a problem, the intake control valves of all cylinders are fully closed to open and close the intake control valves. Therefore, the control of the intake period is stopped and the intake air amount is controlled by the idle speed control valve, so that the idle speed controllability and the intake air amount controllability at the time of extremely low load can be improved.

Also, at the time of idling when the background noise is low,
Since the opening and closing of the intake control valve is stopped, the operating noise caused by the intake control valve can be eliminated.

In the operation state except for the extremely low load,
The effective intake period can be controlled by fully closing the idle speed control valve and opening and closing each intake control valve corresponding to the opening period of the intake valve.

According to the fourth aspect of the invention, in addition to the effects of the third aspect of the invention, at the time of engine stall or engine start, the intake control valves of all cylinders are fully closed, and the idle control is performed based on the engine temperature. Since the opening of the rotation speed control valve is set, at the time of engine stall or engine start, the valve opening of the idle rotation speed control valve is maintained at an appropriate value according to the engine temperature in preparation for engine operation. At this time, since the intake control valves of all cylinders are fully closed, an appropriate intake air amount can be obtained immediately by the valve opening of the idle speed control valve without being affected by the valve opening of the intake control valve. This has the effect of improving engine startability.

According to the fifth aspect of the present invention, when the opening period of the intake control valve is set, the opening period of the intake valve is set based on the required load and the engine speed. In addition to the effects of the invention described in the fourth aspect, there is an effect that an appropriate engine output can be obtained in the entire operation range by adapting to the operation state according to the required load and the engine speed.

In this case, according to the invention described in claim 6, the valve opening period of the intake control valve is corrected according to the engine warm-up state. This has an effect that a suitable intake air amount can be obtained in accordance with the intake air amount. In addition, when the invention is applied to the invention described in claim 1 or each of the inventions dependent on the invention described in claim 1, an idle speed control function can be provided for opening / closing control of the intake control valve.

In the present invention, a target intake air amount is set based on a required load and an engine speed, and the intake control is performed based on a deviation between the target intake air amount and an actually detected intake air amount. Since the opening period of the valve is corrected, the intake air amount can be made to converge to the target intake air amount in each operation region, in addition to the effects of the inventions of the above-described claims 1 to 6, and the intake control valve Of the intake air amount with respect to the target intake air amount due to variations in production of the control valve driving means and the control valve driving unit and the like over time, and the like, can be compensated. As a result, accurate engine output performance can be obtained in each operating region.

According to the present invention, the target intake air amount and the actual intake air amount are determined based on the difference between the target air-fuel ratio set according to the engine operating state and the actually detected air-fuel ratio. Is estimated. The valve opening period of the intake control valve is corrected based on the deviation. Therefore, in addition to the effects of the first to sixth aspects, a sensor for detecting the intake air amount is not provided. Also, the intake air amount can be made to converge to the target intake air amount. As a result, it is possible to compensate for a deviation of the intake air amount from the target intake air amount due to a variation in production of the intake control valve and the control valve driving means and a deterioration with the passage of time. Output performance can be obtained.

According to the ninth aspect of the present invention, the intake control valve is fixed at a predetermined opening when the intake control system is abnormal. Therefore, in addition to the effect of the first aspect, the intake control system and the intake control valve can be controlled. Even if a sensor for detecting a parameter relating to control or a control valve driving means is abnormal and an abnormality occurs in the intake control system, the vehicle travels at a minimum necessary level.

According to the tenth aspect of the present invention, the intake control valve is fixed at a predetermined opening degree when the intake control system is in an abnormal state and the operation state except for an extremely low load is performed. In addition to the effects of the invention, in an operation region in which intake control is performed by the intake control valve, a sensor for detecting a parameter related to control of the intake control valve, or a control valve driving unit, or the like is abnormal, and the intake control system is abnormal. Even if it occurs, there is an effect that the minimum required vehicle traveling can be ensured.

According to the eleventh aspect, when the engine operating state is in the internal exhaust gas recirculation region, at least the valve opening timing of the intake control valve is advanced in angle.
In addition to the effects of the invention described in claim 8, at least in the internal exhaust gas recirculation region such as a low-load medium-low rotation region where nitrogen oxides (NOx) in the exhaust gas increase, at least the opening timing of the intake control valve is advanced. The effective intake period due to the opening period of the intake control valve overlaps with the valve overlap period of the exhaust valve and the intake valve, and internal exhaust gas recirculation (internal EGR) can be performed by the valve overlap. And
The reduction in combustion temperature due to the internal EGR can reduce the amount of NOx emission. Further, since the internal EGR can be controlled only by controlling at least the opening timing of the intake control valve, a complicated and high-cost mechanism for continuously variably controlling the phase of the intake cam or the opening period of the intake valve. Is unnecessary, and the control speed can be drastically improved. Further, the present invention can be realized without employing an external EGR system, and has an effect of preventing contamination of the intake system by EGR gas.

In the twelfth aspect of the present invention, when the operating state is in the cylinder deactivation region in which the cylinder is deactivated, the intake control valve of the predetermined cylinder is fully opened, and at least fuel injection to the cylinder is stopped to stop the cylinder. In addition to the effects of the invention described in claim 1 or claim 3, since the intake control valve is fully opened for the deactivated cylinder, the pumping loss in this deactivated cylinder can be reduced. The fuel consumption can be improved by reducing the fuel consumption.

In this case, according to the thirteenth aspect of the present invention, the cylinders are divided into groups so that combustion is performed at equal intervals, and the cylinder groups are alternately deactivated at predetermined intervals. In addition to the effect, since the deactivated cylinders are alternately changed at predetermined intervals, it is possible to prevent the ignition plug of the deactivated cylinder from being stained by fixing the deactivated cylinder, and to prevent deterioration of ignitability. it can. Also,
To prevent deterioration in flammability of the cylinder when cylinder deactivation is canceled due to a temperature drop of the deactivated cylinder due to fixing of the deactivated cylinder, and to prevent combustion fluctuation between cylinders due to temperature variation between cylinders. Can be. Further, the cylinders are divided into groups so that combustion is performed at equal intervals, and the deactivated cylinders are changed for each group at predetermined intervals. Therefore, fluctuations in engine rotation due to variations in combustion intervals during deactivated cylinders can be prevented.

According to the fourteenth aspect of the present invention, a plurality of cylinders in which the opening periods of the intake valves do not overlap each other are grouped into one group, and the control valve driving means drives the intake control valves in this cylinder group collectively. Claim 1 or Claim 3
In addition to the effects of the described invention, the number of required control valve driving means can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a flowchart of a cylinder discrimination / engine speed calculation routine according to the first embodiment of the present invention;

FIG. 3 is a flowchart of a throttle valve opening / closing timing setting routine;

FIG. 4 is a flowchart of a throttle valve opening / closing timing setting routine (continued)

FIG. 5 is a flowchart of a learning routine according to the first embodiment;

FIG. 6 is a flowchart of a cylinder deactivation control routine;

FIG. 7 is a flowchart of the θ2 crank pulse interruption routine;

FIG. 8 is a flowchart of the θ1 crank pulse interrupt routine;

FIG. 9 is a flowchart of a TMGOPEN interrupt routine.

FIG. 10 is a flowchart of a TMGCLOSE interrupt routine.

FIG. 11 is an explanatory diagram showing valve lift characteristics of an exhaust valve and an intake valve, and a control state of an effective intake period based on a valve opening period of the throttle valve.

FIG. 12 shows a crank pulse, a cylinder discrimination pulse, opening and closing of a throttle valve and opening of an intake valve of each cylinder, and
Time chart showing stroke relationship for each cylinder

FIG. 13 is an explanatory diagram of a throttle valve opening angle table and a throttle valve closing basic angle table according to the first embodiment;

FIG. 14 is a timing chart showing the control state of the throttle valve in each state with respect to the valve lift characteristics of the exhaust valve and the intake valve.

FIG. 15 is an explanatory diagram showing a relationship between a deviation of an intake air amount from a target intake air amount and a learning value;

FIG. 16 is an overall schematic diagram of the engine.

FIG. 17 is a top view schematically showing the main parts of the engine.

FIG. 18 is a schematic configuration diagram of a butterfly type throttle valve and a throttle actuator according to the first embodiment;

FIG. 19 is a schematic configuration diagram of a rotary valve type throttle valve and a throttle actuator;

FIG. 20 is an explanatory view showing an operation state of a rotary valve type throttle valve according to the first embodiment;

FIG. 21 is a front view of the crank angle sensor and the crank rotor according to the first embodiment;

FIG. 22 is a front view of the cylinder discrimination sensor and the cam rotor according to the first embodiment;

FIG. 23 is a circuit configuration diagram of an electronic control system according to the embodiment.

FIG. 24 is a flowchart of a throttle valve opening / closing timing setting routine according to the second embodiment of the present invention;

FIG. 25 is a flowchart of a throttle valve opening / closing timing setting routine (continued)

FIG. 26 is a flowchart of a learning routine according to the third embodiment of the present invention.

FIG. 27 is a top view schematically showing a main part of an engine according to a fourth embodiment of the present invention.

FIG. 28 shows a crank pulse, a cylinder discrimination pulse, opening / closing of a throttle valve and opening of an intake valve of each cylinder, and
Time chart showing stroke relationship for each cylinder

FIG. 29 is an explanatory diagram showing valve lift and timing characteristics of an exhaust valve and an intake valve according to a conventional example.

FIG. 30 is an explanatory view of a lost motion type intake valve according to a conventional example.

FIG. 31 is an explanatory view of an electromagnetically driven intake valve according to a conventional example.

[Explanation of symbols]

Reference Signs List 1 engine 7 intake valve 14, 18 throttle valve (intake control valve) 16, 16A, 16B, 19 throttle actuator (control valve driving means) 28 intake air amount sensor 31 cooling water temperature sensor 32 O2 sensor (linear O2 sensor; air-fuel ratio sensor) ) 34 Crank angle sensor 37 Accelerator sensor 39 Starter switch 40 Electronic control unit (control means, extremely low load determining means) 60 Bypass passage 61 Idle speed control valve (ISC valve) NE Engine speed ACS Accelerator stroke (Accelerator pedal depression amount) THAOPEN Throttle opening angle THACLOSE Throttle closing angle TMGOPEN Throttle opening timing (Throttle valve opening timing) TMGCLOSE Throttle closing timing (Throttle valve closing timing) TW Cooling water temperature (Engine temperature) TW water temperature correction coefficient QATAGT target intake air amount QA of intake air quantity (actual detected intake air amount) .DELTA.Qa deviation KLR learned value KTHLR learning correction coefficient A / FTAGT target air-fuel ratio A / F air-fuel ratio (air-fuel ratio actually detected)

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/04 310 F02D 41/04 310C 315 315 41/06 310 41/06 310 41/08 310 41/08 310 315 315 41/14 310 41 / 14 310P 320 320A 41/22 310 41/22 310M 43/00 301 43/00 301K 301H

Claims (14)

[Claims] 1. An intake control valve disposed immediately upstream of an intake valve of each cylinder for opening and closing an intake passage for each cylinder, control valve driving means for driving the intake control valve to open and close, and an engine operating state. The opening period of the intake control valve within the opening period of the intake valve is variably set based on the opening period of the intake control valve, and for each cylinder, each intake control valve is controlled via the control valve driving means for each cylinder. An intake control device for an engine, comprising: control means for opening and closing to control an intake period. 2. An intake control system for an engine according to claim 1, wherein said control means fixes the intake control valves of all the cylinders to a predetermined opening at the time of engine stall or engine start. 3. An intake control valve disposed immediately upstream of an intake valve of each cylinder, for opening and closing an intake passage for each cylinder, control valve driving means for driving the intake control valve to open and close, and the intake control valve. An idle speed control valve disposed in a bypass passage connected to the intake passage so as to bypass the intake passage; an extremely low load determining means for determining whether or not the operation is an extremely low load; The intake control valve of the cylinder is fully closed and the amount of intake air is controlled by the idle speed control valve.On the other hand, during an operation state except for an extremely low load, the intake valve is controlled based on the engine operation state during the opening period of the intake valve. A control means for variably setting the valve opening period of the intake control valve, and controlling the intake period by opening and closing each intake control valve via the control valve driving means for each cylinder according to the valve opening period of the intake control valve. Engine suction characterized by having Air control device. 4. The control means according to claim 1, wherein when the engine stalls or the engine is started, the intake control valves of all the cylinders are fully closed, and the opening of the idle speed control valve is set based on the engine temperature. The engine intake control device according to claim 3. 5. The intake control system for an engine according to claim 1, wherein the opening period of the intake control valve is set based on a required load and an engine speed. 6. An intake control system for an engine according to claim 5, wherein a valve opening period of said intake control valve is corrected in accordance with an engine warm-up state. 7. The control means sets a target intake air amount based on a required load and an engine speed, and controls the intake control valve based on a deviation between the target intake air amount and an actually detected intake air amount. 7. The intake control device for an engine according to claim 1, wherein the valve opening period is corrected. 8. The control means calculates a deviation between a target intake air amount and an actual intake air amount based on a difference between a target air-fuel ratio set according to an engine operating state and an actually detected air-fuel ratio. 7. The method according to claim 1, further comprising: estimating and correcting the opening period of the intake control valve based on the deviation.
An intake control device for an engine as described in the above. 9. An intake control system for an engine according to claim 1, wherein said control means fixes the intake control valve at a predetermined opening when the intake control system is abnormal. 10. The control means according to claim 3, wherein said control means fixes said intake control valve to a predetermined opening when said intake control system is in an abnormal condition and in an operation state other than an extremely low load. Engine intake control device. 11. The control device according to claim 1, wherein the control means corrects the advance of at least the valve opening timing of the intake control valve when the engine operating state is in the internal exhaust gas recirculation region. Engine intake control device. 12. The control means, when the operating state is in a cylinder deactivated region in which the cylinder is deactivated, fully opens and fixes the intake control valve of the predetermined cylinder, and at least stops the fuel injection to the cylinder to stop the cylinder. The intake control device for an engine according to claim 1 or 3, wherein the engine is stopped. 13. The intake control of an engine according to claim 12, wherein said control means divides the cylinders into groups so that combustion is performed at equal intervals, and alternately suspends the cylinder groups at predetermined intervals. apparatus. 14. The control valve driving means collectively drives a plurality of cylinders in which the valve opening periods of the intake valves do not overlap with each other, and the control valve driving means drives the intake control valves in the cylinder groups collectively. Alternatively, the intake control device for an engine according to claim 3.