JPH0610438B2 - Fuel control system for combined intake engine - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a device for controlling the fuel quantity of a hybrid intake engine.

[Conventional technology]

2. Description of the Related Art Conventionally, in an automobile engine that uses gasoline as fuel, it is necessary to detect the flow rate of air passing through the intake passage or the pressure in the intake passage and supply it to the combustion chamber based on the detection result. Adjustment of the fuel amount is performed.

[Problems to be solved by the invention]

However, when the conventional fuel control device for an engine is simply applied to a composite intake type engine, in the case where fuel is supplied to the intake passage, the operation of the secondary intake valve is limited (hereinafter, this state is referred to as "P"). "), The air-fuel ratio A / F supplied to the combustion chamber is temporarily changed when the operation restriction of the secondary intake valve is resolved (hereinafter, this state is represented by reference sign" P + S "). However, there is a problem that the output of the engine changes and a shock is generated.

That is, since an extremely thin air-fuel mixture is retained in the secondary intake passage when the operation of the secondary intake valve is restricted, immediately after releasing the operation restriction of the secondary intake valve, the intake port wall surface of the secondary intake system is Therefore, the amount of fuel adhering to the combustion chamber increases, and the air-fuel mixture supplied to the combustion chamber becomes thinner.

The present invention is intended to solve such a problem, and is supplied to the combustion chamber even when switching from the operation restriction state of the secondary intake valve to the state where the operation restriction of the secondary intake valve is released. SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel control device for a combined intake type engine capable of preventing the occurrence of switching shock by making it possible to keep the air-fuel ratio of the air-fuel mixture substantially constant.

[Means for solving problems]

Therefore, the fuel control system for a combined intake type engine of the present invention includes a primary intake system having a primary intake valve, a secondary intake system having a secondary intake valve, the primary intake valve and the secondary intake system. A valve drive mechanism that opens the intake valve in synchronism with the first stroke phase of the engine and repeatedly operates each valve to close it in synchronism with the second stroke phase, and limits the operation of the secondary intake valve. A valve operation limiting mechanism that suppresses the amount of intake air that flows into the combustion chamber of the engine via a secondary intake valve, and outputs a first signal when the operating state of the engine shifts to a specific operating state and also performs the specific operation. Second when you get out of the state
Switching signal output means for outputting the signal, and limiting the operation of the secondary intake valve in response to the output of the first signal and limiting the operation of the secondary intake valve in response to the output of the second signal. The valve operation limiting mechanism is operated in synchronization with the third stroke phase from the second stroke phase to the next first stroke phase after the output of the first or second signal in order to release Secondary intake valve control means, intake air amount detection means for detecting the intake air amount of the engine, and fuel for supplying fuel to the intake passage of the engine according to the intake air amount detected by the intake air amount detection means. Supply means, fuel increase control means for temporarily increasing the amount of fuel supplied to the intake passage in response to the second signal, and synchronization with the third stroke phase from the time when the second signal is output. Then, the operation restriction of the secondary intake valve The secondary intake valve is not added to the intake air sucked into the combustion chamber in the intake stroke executed until it is removed and is synchronized with the third stroke phase. In the intake stroke that is first executed after the operation restriction of (1) is released, the fuel increase control means starts the fuel increase amount so that the fuel increase amount is added to the intake air sucked into the combustion chamber. It is characterized in that it is provided with a fuel amount increase start timing setting means for synchronizing with a fourth stroke phase from the third stroke phase in which the operation restriction of the secondary intake valve is released to the next first stroke phase. .

[Work]

With the above-described configuration, release of the operation restriction state of the second intake valve from the operation restriction state of the secondary intake valve (that is, the state in which the amount of intake air flowing into the combustion chamber via the secondary intake valve is suppressed), Since it is positively synchronized with a predetermined stroke phase of the engine and the start time of fuel increase is set between the predetermined stroke phase and the next intake stroke, the fuel is supplied to the combustion chamber regardless of the engine speed. The air-fuel ratio of the air-fuel mixture is always appropriate.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a fuel control system for a compound intake type engine as an embodiment of the present invention. FIG. 1 is an overall configuration diagram and FIG. 2 is a configuration diagram showing a valve operation stopping device of an engine valve system. FIG. 3 is a partial plan view of the lock plate, FIG. 4 is a configuration diagram of relevant parts, FIG. 5 is a vertical cross-sectional view of relevant parts of the engine, and FIG. 6 is a schematic diagram illustrating essential parts of the engine. The plan views, FIGS. 7 to 11 and FIGS. 12 (a) to (h) are all graphs for explaining the operation, and FIGS. 13 to 17 are flow charts for explaining the operation. .

As shown in FIGS. 1 to 6, an internal combustion engine E such as an in-line four-cylinder gasoline engine mounted on a vehicle according to this embodiment is used.
The engine (hereinafter simply referred to as “engine E”) has a turbocharger 3. The turbocharger 3 includes a turbine 4 installed in the exhaust passage 2 of the engine E and a compressor 5 installed in the intake passage 1 of the engine E and rotationally driven by the turbine 4.

A bypass passage that bypasses the turbine passage portion of the exhaust passage 2 is connected to the exhaust passage 2, and a waste gate valve 6 that opens and closes the bypass passage is provided. The waste gate valve 6 is configured to be opened and closed by a two-diaphragm visual pressure response device 7, and an electromagnetic switching valve 34 (the valve 34 has a return spring (not shown) for the valve body) By selectively supplying the atmospheric pressure and the supercharging pressure to one pressure chamber of the pressure response device 7, it is possible to adjust the opening timing of the waste gate valve 6 and the like and realize at least two types of supercharging pressure characteristics. ing.

In the intake passage 1 of the engine E, an air flow sensor 16, a compressor 5, an intercooler 8 of the turbocharger 3, an electromagnetic fuel injection valve 9, 10 (these valves 9, 10 are arranged in this order from the upstream side (air cleaner side) thereof. Have different injection capacities) and a throttle valve 11, and the exhaust passage 2 of the engine E has an upstream side (engine combustion chamber side) thereof.
In this order, the turbine of the turbocharger 3, the catalytic converter 31, and a muffler (not shown) are provided.

As shown in FIG. 4, the shaft 11a of the throttle valve 11 arranged in the intake passage 1 of the engine E is connected to the throttle lever 11c outside the intake passage 1.

When the accelerator pedal (not shown) is depressed at the end 11d of the throttle lever 11c, the throttle lever 11c
A wire (not shown) for rotating the throttle valve 11 in the clockwise direction (opening direction) in FIG. 4 is connected to the throttle valve 11 by means of, and the throttle valve 11 is urged in the closing direction. When a return spring (not shown) is installed to weaken the pulling force of the wire, the throttle valve 1
1 is closed.

By the way, when the engine is idle, the throttle valve 11
An actuator 12 for controlling the opening degree of the worm 14a is provided on the rotary shaft.
A DC motor (hereinafter simply referred to as "motor") having 1
The worm 14a with the moh 13 meshes with the annular worm wheel 14b.

The worm wheel 14b is integrally provided with a pipe shaft 14c having a female screw portion 14d, and a rod (stopper member) 15 having a male screw portion 15a screwed to the female screw portion 14d of the pipe shaft 14c is attached to the worm wheel 14b. And, it is attached by penetrating the pipe shaft 14c.

Then, the tip of the rod 15 is connected to the throttle lever 11 via an idle switch 25 as an idle sensor.
The end 11d of c is brought into contact with the throttle 11 when the throttle 11 is fully closed. That is, the rod 15 regulates the fully closed stop position of the throttle valve 11.

Here, the idle switch 25 is a switch that is turned on (closed) when the throttle valve 11 is at the fully closed stop position (during engine idle operation), and turned off (open) at other times.

An elongated hole 15b is formed in the rod 15, and a pin (not shown) on the actuator body side is guided in the elongated hole 15b, which prevents the rod 15 from rotating. It's peeled off.

As described above, since the tip of the rod 15 is in contact with the engine E when the engine E is in the idle state, the motor 13 is rotated in a certain direction to rotate the pipe shaft 14c via the worm gear, and the rod 15 is rotated. When 15 is projected (moved forward) from the actuator 12, the throttle valve 11 is opened, the motor 13 is rotated in the reverse direction, and the rod 15 is retracted (retracted) into the actuator 12, and the throttle valve 11 is returned to the spring. Can be controlled to close by the action of.

That is, by driving the rod 15, the fully closed stop position of the throttle valve 11 can be changed to control the idle opening degree of the throttle valve 11.

In the present embodiment, the CIS engine is provided with a primary intake system and a secondary intake system that communicate with each cylinder S _{1 to} S ₄ , and this engine E has a primary intake system 1P and a full engine rotation speed. The secondary intake system 1S is provided with a primary intake valve 40 that operates over a range, and the secondary intake system 1S is provided with a secondary intake valve 41 that stops operating in a low engine speed range and starts operating in a high engine speed range. .

In the engine valve system of this embodiment, the primary intake valve 4
The 0, secondary intake valve 41 and exhaust valve 42 are configured to be opened and closed by a rocker arm and a cam as a valve drive mechanism, respectively. As shown in FIG. 2, the secondary intake valve 119 is opened and closed by a cam 101. The rocker arm 102 to be driven is provided with a valve operation stopping mechanism M'as a valve operation limiting mechanism. That is, rocker arm 1
A cylinder 112 is attached to 02, and a bottomed cylindrical plunger 113 is slidably fitted in the cylinder 112. The plunger 113 is pressed downward in FIG. 2 by the spring 114 mounted therein, and the bottom surface of the lower end of the plunger 113 has the secondary intake valve 11
9 is in contact with the valve shaft end.

Two elongated holes 112a face the cylindrical wall of the cylinder 112 at a position directly above the upper end of the plunger 113 when the plunger 113 is at the lowest position (position shown in the drawing) with respect to the cylinder 112. The lock plate 106 constituting the locking mechanism EN is inserted into these elongated holes 112a.

A two-forked fork portion is formed at the tip of the lock plate 106. As shown in FIG. 3, the forked fork portion has a narrow gap portion whose tip portion is approximately equal to the inner diameter of the plunger 113. 106a, and a portion near the base end thereof is formed as a wide gap 106b that is slightly wider than the outer diameter of the plunger 113.

Further, the rocker arm 102 is interposed between a cylinder 104, a piston 105 that slides in the cylinder 104, and is interposed between the piston 105 and the spring bearing 108 to press the piston 105 to the right in FIG. A hydraulic actuator 103 including a return spring 107 is provided.

The piston 105 and the lock plate 106 are connected to each other, and the connecting portion 133 is as follows.

That is, at the outer end of the piston 105, the piston 105
A tubular connecting member having a quadrangular cross section at a right angle with respect to the sliding direction is fixed, and a hook-shaped portion having a substantially C shape provided on the piston 105 side of the lock plate 106 extends along the sliding direction of the piston 105. Is provided so as to surround the connecting member with a gap therebetween, whereby the lock plate 106 and the piston 105 are connected with a gap.

Furthermore, the timing cam 1 is attached to the rocker shaft 124.
25 is provided, and the timing cam 125 is
When the rocker arm 102 swings to the maximum or its vicinity (the cam lift is the maximum or its vicinity), the timing follower 126, which has a substantially cylindrical shape, is slid largely outward in the radial direction of the rocker shaft 124. ing.

Further, the timing plate 109 is used for the rocker arm 10.
The piston 105 is rotatably supported by a shaft attached to the main body 2 and is slid in a groove 104a provided outside the cylinder 104, and is provided above the left end portion and the middle portion of the piston 105 in the figure. It is configured to be engageable with the cut 105a.

Further, the timing plate 109 is biased in the piston engagement direction by the spring, and when the timing cam follower 126 is pushed upward by the timing cam 125 in FIG.
6 is rotated so that the engagement with the piston 105 is released. Note that the oil chamber 110 of the cylinder 104 in the actuator 103 is the rocker arm 102.
Irrespective of the swing of the
Is always communicated with the oil passage 123 in the rocker shaft 124.

Since the lock plate 106 and the actuator 103 for driving the lock plate 106 are configured as described above, when the pressure oil is supplied to the actuator 103, the lock plate 106 is caused to protrude at a required timing (stroke phase), and the lock plate 106 is then projected. The wide gap portion 106b of the plunger 1 is located above the plunger 113.
Reference numeral 13 denotes a cylinder 112 as the rocker arm 102 swings.
By sliding inside, a valve stop state can be realized, and the amount of intake air flowing into the combustion chamber via the secondary intake valve 119 can be suppressed.

Further, when the oil is discharged from the actuator 103, the lock plate 106 is retracted at a required timing (stroke phase) by the action of the return spring 107, and the narrow gap portion 106a of the lock plate 106 is positioned above the plunger 113. , This makes the plunger 11
3 can be locked to the lock plate 106 to realize a valve operating state.

Further, a hydraulic pressure supply system for supplying a high hydraulic pressure to the oil passage 123 is provided, and the pump 51 supplies the hydraulic oil from the oil tank 52 to the oil passage 123 through the oil passage 53.

Then, an oil control valve (O
CV) 50 is installed, and this solenoid 50a is O
When receiving the control signal from the CV control means M1, O
The CV 50 is turned on to bring the oil passage 53 into communication, and the solenoid 50a is connected to the OCV control means M.
When the control signal from 1 is not received, the OCV 50 is turned off (OFF) and the pressure oil in the oil passage 123 is transferred to the oil passage 54.
To discharge.

That is, the OCV control manual step M1, the oil passage 53, the OCV5
0, timing cam 125, timing cam follower 1
26, the timing plate 109 constitutes a secondary intake valve control means.

Further, reference numeral 121 in FIG. 2 indicates a valve spring 120.
Shows a spring bearing for.

The OCV control means M1 is the air-fuel mixture increase control means M.
2, an actuator control unit M3, a fuel supply amount setting unit M4, etc., and the controller 27.

By the way, the controller (computer) 29 has a microprocessor (CPU) as a main control unit, and the output from the A / D converter is input to this microprocessor via a bus line, and The frequency-divided output of the airflow sensor 16 from the frequency-dividing circuit, the output from the O ₂ sensor 22 (this output is actually supplied via a comparator), and the output from the rotation speed sensor 17 are input.

The microprocessor, based on the information from the sensors 17 to 28, multiplies the basic data by the correction coefficient to obtain the fuel injection pulse width Tout and supplies the fuel to the intake passage of the engine. Of the fuel supply amount setting means M4 configured to include the fuel increase control means for increasing the supplied fuel according to the output of the means and the fuel increase start timing setting means for setting the start timing of the fuel increase by the fuel increase control means. It has a function.

Then, the microprocessor supplies its control output to a timer circuit having three timers via a bus line. Here, the two timers are for the fuel injection valves 9 and 10 and turn on / off the solenoid coils of the fuel injection valves 9 and 10.

The timer is for triggering the control means M5.

By the way, when the engine output is plotted on the vertical axis and the engine speed is plotted on the horizontal axis, there are various operating modes of this engine.

Then, the microprocessor multiplies the basic data by an appropriate correction coefficient according to the operation mode and outputs desired fuel injection pulse width Tout information to the timer circuit.

Further, a throttle sensor 20 for detecting the opening of the throttle valve 11 (throttle opening) is provided, and as the throttle sensor 20, a potentiometer or the like that generates a voltage proportional to the throttle opening is used.

Further, as shown in FIG. 1, a water temperature sensor 21 for detecting a cooling water temperature as a warming-up temperature of the engine E is provided, and the engine speed is, for example, ignition pulse information obtained from the primary minus terminal of the ignition coil 32. A rotation speed sensor 17 is provided for detecting.

Furthermore, a vehicle speed sensor 24 for detecting the vehicle speed with a pulse signal having a frequency proportional thereto is provided, and as the vehicle speed sensor 24, a known reed switch is used.

Further, a cranking switch 26 is provided as a cranking sensor for detecting an engine cranking state. The cranking switch 26 is on (closed) when the starter motor is turned on, and is off (open) otherwise.
Is a switch.

By the way, the air flow sensor 16 detects the number of Karman vortices generated by the columnar body arranged in the intake passage 1 by the ultrasonic modulator or by detecting the change in the resistance value. Of the intake air amount, and the digital output from the air flow sensor 16 is input to the controller 29. The digital output from the air flow sensor 16 is, for example, applied to various processes after being applied to, for example, a 1/2 frequency divider in the controller 29.

Further, it is generally said that the air flow sensor 16 malfunctions due to intake pulsation or the like in a low speed and high load state of the engine E, but in the present embodiment, the intercooler 8 is provided on the downstream side of the air flow sensor 16 and the dimensions and the like of the air cleaner portion are appropriately adjusted. By doing so, since the above-mentioned intake pulsation hardly occurs, it is considered that the measurement reliability or accuracy of the air flow sensor 16 is sufficiently high.

Further, in addition to the sensors and switches described above, an intake air temperature sensor 18 for detecting the intake air temperature, an atmospheric pressure sensor 19 for detecting the atmospheric pressure, an O ₂ sensor 22 for detecting the oxygen concentration in the exhaust gas,
A knock sensor 23 that detects an engine knock state, a crank angle 27 that detects a crank angle by a photoelectric conversion means with a distributor 33, and a reference opening of the throttle valve 11 (this opening is, for example, an engine speed of 600 rp).
It is set as a small opening corresponding to around m. )
Is provided with a motor position switch 28 or the like as a position sensor for detecting the position (reference position) of the rod 15 with the actuator 12 corresponding thereto, and signals from these sensors and switches are input to the controller 29. Has become.

As shown in FIG. 4, the motor position switch 28 is provided rearward of the rear end surface of the rod 15, and is turned on (closed) in the vicinity of the most retracted state of the rod 15 and turned off (open) at other positions. Is configured to be.

Further, since the intake air temperature sensor 18, the atmospheric pressure sensor 19, the water temperature sensor 21, the throttle sensor 20, the O ₂ sensor 22, the knock sensor 23, etc., have detection signals which are analog signals, the controller 29 via the A / D converter. Is input to.

The atmospheric pressure sensor 19 may be incorporated in the controller 29.

Further, an ignition coil 32 is provided, and the ignition coil 32 is configured so that the primary side current is interrupted by a power transistor 30 as a switching transistor.

Further, a display meter 35 is provided in the vehicle compartment.

As the indicator 35, one having a needle type display portion 35a, one having light emitting diodes (LEDs) arranged in a row and having a segment type display portion 35b in which these LEDs blink appropriately can be considered. .

By the way, the controller 29 is configured to include a CPU, a memory (including a map), and an appropriate input / output interface. The controller 29 is configured to detect the idle operation state by the idle switch 25 (when the idle switch is in the on state). Under the set condition I (when the engine speed is smaller than a predetermined value), the engine speed feedback control (rotation speed feedback control) is performed by the signal from the speed sensor 17 while
Under the other set condition II when the idle state is detected, in order to perform the position feedback control of the throttle valve 11 by the signal from the throttle sensor 20, the idle switch 25, the rotation speed sensor 17, the throttle sensor 20, the vehicle speed, It has a function of an idle control means for receiving the detection signals from the sensor 24 and outputting an idle control signal based on these detection signals to the motor 13 of the actuator 12.

Also, when performing the rotational speed feedback control,
When the target engine speed is changed according to the cooling water temperature as shown in FIG. 7 and the position feedback control is performed, the target throttle opening is changed according to the cooling water temperature as shown in FIG.

Further, the drive time Δ of the motor 13 of the actuator 12
The relationship between D and the deviation ΔN or ΔP is 9th,
It is as shown in FIG. Here, the deviation ΔN means the difference between the actual engine speed and the target engine speed, and the deviation ΔP means the difference between the actual throttle opening and the target throttle opening.

The condition I means that at least the following items are satisfied, and the condition that the engine is relatively stable.

(1) A predetermined time has elapsed after the idle switch 25 changed from off to on.

(2) The vehicle speed is extremely low (for example, 2.5 km / h or less).

(3) The deviation of the actual engine speed (actual speed) from the target speed must be within the specified range.

(4) For vehicles with a cooler, the specified time has elapsed after the cooler relay etc. was switched according to the cooler load.

The condition II means a condition when the condition I is not satisfied, the engine is not relatively stable, and quick feedback control is desired.

Since the fuel control device for the combined intake type engine of the present invention is configured as described above, the fuel injection pulse width setting flow as the fuel supply amount setting means M4 is performed by turning on the key switch as shown in FIG. , Memory L, M, J,
Although S is reset and triggered by interruption of each ignition signal, in step A1,
Operating state information [air supply amount (intake air amount) Aq, air supply temperature A
t, cooling water temperature TW, engine speed NR, throttle opening PR, change speed (acceleration information) d (PR) / dt, oxygen concentration in exhaust gas O ₂ and idle switch on / off information IS
W] is read.

Next, at step A2, it is judged if the idle switch 25 is on, that is, if the throttle opening is fully closed.

If the idle switch 25 is off (throttle valve 11
Is open), the basic injection pulse width τb corresponding to Aq (air supply amount) is set in slop A5. The pulse width τb is obtained from a signal obtained by appropriately dividing the output of the air flow sensor 16 according to the operation mode (this division ratio may be fixed depending on the operation mode, but may be changed). It can be obtained or obtained from the output signal of the rotation speed sensor 17.

Then, in step A6, various correction coefficients K ₁ , ... According to the operating state [TW (cooling water temperature), At (supply air temperature), acceleration, O ₂ feedback, outside temperature, etc., respectively.
Kn (warm-up correction coefficient, outside air temperature correction coefficient, etc.)] is set.

Next, in block KK, the switching fuel increase coefficient Kp is set by the fuel increase control means and the fuel increase start timing setting means.

That is, in step A7, it is determined whether or not the memory L is zero, and since the initial value of the memory L is zero,
Next, in block AA, it is judged whether or not the value of the memory J is zero (step A8). Since the initial value of the memory J is zero also in this case, the process goes to step A9.

At step A9, the value of the memory M is set to the set value M1 (≧ 0,
Here, it is determined whether or not it is equal to 2), and since M = 0, the process goes to step A10, and further, the YES route is taken and it is determined that the P region is switched to the P + S region (step A11). , A12), Step A
In step 13, M = 1 is set, and the fuel increase coefficient Kp is set to "1".
(Step A14).

That is, the fuel is not increased, and the time at this time is
It is indicated by the symbol T ₁ in FIGS. 12 (a) to 12 (h).

When the P + S area is switched to the P area or when the P area is not switched, the memory M is not set, and the process proceeds to step A14.

Next, at the next ignition pulse (time T ₂ ), NO is determined in step A10, and the content of the memory M is incremented by 1 to become “2” (step A15).
The fuel increase coefficient Kp remains in the state of "1" (step A14).

Further, at the next ignition pulse (time T ₃ ), it is determined that M = M1 in step A9, so YES.
The memory M is reset via the route (step A1
6) The value of the memory L is set to a set value N (here, 2) (step A17), the value of the memory J is set to "1" (step A18), and the value of the memory S is set to the increased fuel value K.
₀ (> 1) (step A19).

Then, the increased fuel value K ₀ is set to the fuel increase number K _p (step A20).

Further, at the next ignition pulse (time T ₄ ), it is determined in step A7 that L ≠ 0, and then in step A21, the value of the memory L is subtracted, and the value of the fuel increase coefficient K _p is increased. Maintain the value K ₀ .

At the next ignition pulse (time T ₅ ), the same processing as at time T ₄ is performed, and L = N−2 = 0, and at the next ignition pulse (time T ₆ ), from step A7. After the YES route, the value of the memory J is determined in step A8, and since J = 1, the value of the memory S is subtracted by ΔK in step A22.

Then, in step A23, it is determined whether or not the value of the memory S is less than 1, and if it is 1 or more, in step A24, the subtracted value of the memory S (K ₀ > S ≧).
1) is set as the fuel increase coefficient K _p .

At each ignition pulse (time T _{7 to} T ₉ ), the same process as at time T ₆ described above is performed, and the value of the memory S is subtracted by ΔK.

When the value of the memory S becomes less than 1 at the ignition pulse at time T ₁₀ , the YES route is followed by step A25,
The value of the memory J is reset, and the value of the fuel increase coefficient _Kp is set to "1".

At time T _{10 J} or later, to switch the P → P + S is performed, the value of the fuel increase coefficient K _p is kept "1".

Thus, in block KK, the value of the fuel increase coefficient K _p is of being appropriately determined in the range of 1 to K _0.

Then, after the processing of block KK, in step A26, the fuel injection pulse width T _out is set so as to satisfy the following equation.

T _out = τb × K ₁ × K ₂ × ... × K _n × K _{p When} the idle switch 25 is on, NR ≧ NS1 (NS1; positive predetermined value) in step A3 of FIG. ) Is determined, and if NR ≧ NS1,
In step A4, it is determined whether or not TW ≧ TWS (TWS; a positive predetermined value).

If the conditions in step A3 or step A4 are not satisfied, the process of step A5 is performed next.
If the conditions in steps A3 and A4 are both correct, the fuel injection pulse width T _{out is set} to τd (τd; 0 or a very small value) in step A27 in FIG. As a result, a so-called fuel cut or a state close to this can be achieved.

Next, the flow of processing by the switching signal output means and the OCV control means M1 described above is shown in FIG. 14, and this processing flow is caused by interruption for each ignition pulse.

That is, first, in step B1, various data (engine speed NR, throttle valve opening PR) are input, and then the switching signal output means sets P based on this data.
A determination signal of whether it is a region is output (step B
2).

If it is the P region, the OCV 50 is turned off by the OCV control means M1 in step B3, and if it is the P + S region, the OCV 50 is turned on in step B4.

In this way, as shown in FIGS. 12 (a) to 12 (h), the state where only the primary intake valve 40 is operating is changed to the primary intake valve 40
And the cylinder in which the intake stroke is first executed after the state where the secondary intake valve 41 is operated is changed to the switching signal (reference time:
The first pulse) is generated [see FIG. 12 (b)], and the OCV 50 is turned off at the required timing [see FIG. 12].
[see (c)], and the cylinder in the intake process [see FIG. 12 (d)].

The intake amounts of the primary intake valve 40 and the secondary intake valve 41 to this cylinder change as shown in FIGS. 12 (e) and 12 (f), respectively, and are supplied to the combustion chamber.

The fuel increase coefficient K _p, as shown in Fig. 12 (g), the fuel increase is performed from the third pulse, the ignition pulse and the EGR map is changed from the P map to P + S map.

Then, since the fuel amount is increased with respect to the intake air that is initially taken in while the secondary intake valve is operating in this manner, the secondary intake system 1S (see FIG. 5) leading to the secondary intake valve 41 is connected. Sufficient fuel is sent, and the air-fuel mixture maintained at a predetermined air-fuel ratio A / F is supplied to the combustion chamber.

Thus appropriately adjusted with the gas mixture at the ignition timing instructed by the P + S map is being explosion (time T _6).

Then, from time T ₆ to time T ₁₀ , the fuel decreases in a stepwise manner, so sufficient fuel is sequentially sent to the secondary intake system 1S leading to the other cylinders, and the predetermined air-fuel ratio A / F is reached. The maintained air-fuel mixture is supplied to the combustion chamber.

At time T ₁₀ later, the increasing correction of the fuel does not need, not performed.

By the way, when the delay of the valve stop switching operation is longer than the delay of the fuel supply to the combustion chamber, the OCV control means M1 is executed according to the process flow shown in FIG.

That is, first, the memory R is reset (= 0) at the start.
After various data (engine speed NR, throttle opening PR, cooling water temperature TW, etc.) are input in step C1, response delay during normal operation (valve stop switching operation delay, etc.) is considered. Then, the ignition pulse number R1 corresponding to the delay time is preset and compared with the value in the memory R (step C2), and switching between P and P + S (see FIG. 11).
Is determined (steps C3 and C4),
At the time of this determination, the content of the memory R becomes "1" (step C5), and the on / off state of the OCV 50 is maintained as it is (step C6).

Then, by the next ignition pulse, R ≠ R in step C2.
1 (that is, when R <R1), steps C3 to N
Through the O route, the content of the memory R is increased (+1) in step C7, and the operating state of the OCV 50 is maintained as it is (step C6).

Then, in such a state, in step C2, R
Repeated until = R1.

When R = R1, the contents of the memory R are reset (step C8), it is determined whether the operating region is the P region (step C9), and when the engine is started, it is the P region, so YES. OCV50 via the route
Is turned on (step C10), and in the other P + S region, the OCV 50 is turned off via the NO route (step C11).

In addition to setting the fuel injection pulse width T _out in consideration of the operation delay of the OCV 50 as described above, the first
A block AA shown in FIG. 3 (that is, a processing flow of the fuel increase start timing setting means) is shown in block A in FIG.
What is replaced with A ′ may be used, and in this replaced processing flow, a valve stop mechanism with almost no operation delay of the OCV 50 is used.

Although the present embodiment shows an example applied to a four-cylinder engine, the same thing can be done in an engine having other number of cylinders. The fuel is increased in amount from the pulse so that the amount of fuel and the amount of increased fuel determined by the shape of the intake passage and the arrangement of the fuel supply device are supplied to the intake passage, and the explosion starts from the seventh pulse. It is done.

In this way, when the operating range shifts from the operation of only the primary intake valve to the operation of the primary intake valve and the secondary intake valve, when the idling opening of the throttle valve is It becomes larger than the idling opening.

Since switching between the P area and the P + S area shown in FIG. 11 is configured so as to be instructed by two maps, by setting the overlapping portion of the P map and the P + S map in advance, P → P + S switching and P
It is also possible to set by changing the condition of engine speed-output of switching + S → P.

That is, this overlapping portion functions as a hysteresis zone, and as an example, at the same output, P → P
The engine speed at the time of + S switching is set to be higher than the engine speed at the time of P + S → P switching.

This hysteresis zone is set by the cooling water temperature TW.
May be limited to when the water temperature is equal to or higher than the set water temperature TWS.
The confirmation time (t ₂ seconds; t ₂ <1) may be adopted for the zone determination in consideration of prevention of hunting due to rotation fluctuation during sudden acceleration.

Further, after P → P + S switching, re-switching may be prohibited for a certain period of time to stabilize the operating state of the valve operation stopping mechanism M ′.

When the key switch is turned off, the current of the oil pump 51 is turned on for t ₁ seconds, the OCV 50 is turned on, and the operation of the secondary intake valve 41 is stopped, so that the next start is performed by turning on the secondary intake valve 41. The startability may be ensured as the P state to be stopped.

Further, by using an injector type fuel supply means, it is possible to control the air-fuel mixture amount without depending on the control of the opening degree of the throttle valve.

In the present embodiment, the pair of electromagnetic fuel injection valves 9 and 10 having different capacities are always operated, and the fuel injection amount is controlled by controlling the injection time width. The injection valves 9 and 10 may be switched.

〔The invention's effect〕

As described above in detail, in the fuel control system for a composite intake type engine of the present invention, the secondary intake air is synchronized with the third stroke phase of the engine in response to the output of the second signal output by the switching signal output means. The fuel amount increase control means for releasing the operation limit of the valve and adding the fuel amount to the intake air sucked into the combustion chamber in the intake stroke first executed after the operation limit of the second intake valve is released. Is set to the fourth stroke phase from the third stroke phase to the next first stroke phase (next intake stroke), that is, the operation limit of the second intake valve is set. Since the release is positively synchronized with the predetermined stroke phase of the engine and the start timing of the fuel increase is set between the predetermined stroke phase and the next intake stroke, the fuel chamber is irrespective of the engine speed. Mixed supplied to Can make the air-fuel ratio of the air always appropriate, even during the switching from the operating limit state of the secondary intake valve to a state in which operation restrictions are canceled secondary intake valve,
The air-fuel ratio of the air-fuel mixture supplied to the combustion chamber can be kept substantially constant, and the occurrence of switching shock can be prevented.

[Brief description of drawings]

FIG. 1 shows a fuel control system for a compound intake type engine as an embodiment of the present invention. FIG. 1 is an overall configuration diagram and FIG. 2 is a configuration diagram showing a valve operation stopping device of an engine valve system. FIG. 3 is a partial plan view of the lock plate, FIG. 4 is a configuration diagram of relevant parts thereof, FIG. 5 is a longitudinal sectional view of relevant parts of the engine, and FIG. 6 is a schematic diagram showing essential parts of the engine. The plan views, FIGS. 7 to 11 and FIGS. 12 (a) to (h) are all graphs for explaining the action, and FIGS. 13 to 17 are flowcharts for explaining the action. 1 ... Intake passage, 1P ... Primary intake system, 1S ... Secondary intake system, 2 ... Exhaust passage, 3 ... Turbocharger, 4 ...
... Turbine, 5 ... Compressor, 6 ... Wastegate valve, 7 ... Pressure response device, 8 ... Intercooler, 9, 10 ... Electromagnetic fuel injection valve, 11 ... Throttle valve, 11a ... Shaft, 11c ... throttle lever, 1
1d ... end of throttle lever, 12 ... actuator, 13 ... motor, 14a ... worm, 14b ...
Worm wheel, 14c ... Pipe shaft, 14d ... Female thread part, 15 ... Rod, 15a ... Male thread part, 15b
...... Oval hole, 16 ...... Air flow sensor, 17 ...... Revolution speed sensor, 18 ...... Intake air temperature sensor, 19 ...... Atmospheric pressure sensor, 20 ...... Throttle sensor, 21 ...... Water temperature sensor,
22 …… O ₂ sensor, 23 …… knock sensor, 24 ……
Vehicle speed sensor, 25 ... Idle switch as idle sensor, 26 ... Cranking switch, 27 ... Crank angle sensor, 28 ... Motor position switch, 29 ... Controller, 30 ... Power transistor, 31 ... Catalytic converter , 32 ... Ignition coil, 33 ... Distributor, 34 ... Electromagnetic switching valve, 35 ... Indicator, 35a ... Needle type display section, 35
b ... Segment type display, 36 ... Ignition key switch, 37 ... Battery, 40 ... Primary intake valve,
41 ... Secondary intake valve, 42 ... Exhaust valve, 50 ... Oil control valve (OCV), 50a ... Solenoid, 51 ... Pump, 52 ... Oil tank, 53, 5
4 ... Oil passage, 101 ... Cam, 102 ... Rocker arm, 103 ... Actuator, 104 ... Cylinder,
104a ... Groove, 105 ... Piston, 105a ... Notch, 106 ... Lock plate, 106a ... Narrow gap part, 106b ... Wide gap part, 107 ... Return spring, 108 ... Spring receiver, 109 ... Timing plate, 110 ... Oil chamber, 111 ... Oil passage, 112 ... Cylinder, 112a ... Oblong hole, 113 ... Plunger, 11
4 ... Spring, 119 ... Secondary intake valve, 119a ...
… Stem for secondary intake valve, 120 …… Valve spring,
121 ... Spring bearing, 122, 123 ... Oil passage, 124
...... Rocker shaft, 125 ...... Timing cam, 12
6 ... Timing cam follower, 133 ... Connection part between lock plate and piston, E ... Engine, EN ...
... Locking mechanism, M '... Valve stop mechanism, M1 ... OCV
Control means, M2 ... Mixture amount increase control means, M3 ... Actuator control means, M4 ... Fuel supply amount setting means, S
_{1 to} S ₄ ... Cylinder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-188039 (JP, A) Actually opened 59-196931 (JP, U) Actually opened 57-196220 (JP, U) JP-B 56- 42739 (JP, B2)

Claims (1)

[Claims] 1. A primary intake system having a primary intake valve, a secondary intake system having a secondary intake valve, the primary intake valve and the secondary intake valve in a first stroke phase of an engine. A valve drive mechanism that opens in synchronism and repeatedly operates to occlude in synchronism with the second stroke phase, and the combustion of the engine through the secondary intake valve by limiting the operation of the secondary intake valve. A valve operation limiting mechanism that suppresses the amount of intake air flowing into the room,
When the operating state of the engine shifts to a specific operating state, the first
Switching signal output means for outputting a second signal when the specified state is exited, and the first signal
The operation of the secondary intake valve is restricted in response to the output of the signal and the operation restriction of the secondary intake valve is released in response to the output of the second signal.
Or secondary intake valve control means for operating in synchronization with the third stroke phase between the second stroke phase and the next first stroke phase after the output of the second signal, and the intake air amount of the engine An intake air amount detecting means for detecting, and a fuel fuel supplying means for supplying fuel to the intake passage of the engine according to the intake air amount detected by the intake air amount detecting means,
A fuel increase control means for temporarily increasing the amount of fuel supplied to the intake passage in response to the second signal;
For the intake air that is taken into the combustion chamber in the intake stroke that is executed from the time when the signal is output until the operation restriction of the secondary intake valve is released in synchronization with the third stroke phase. Intake that is sucked into the combustion chamber in the intake stroke that is first executed after the operation restriction of the secondary intake valve is released in synchronization with the third stroke phase without adding the fuel increase amount. In order to add the fuel increase amount, the fuel increase amount control means starts the fuel increase amount from the third stroke phase in which the operation restriction of the secondary intake valve is released to the next first stroke phase. And a fuel amount increase start timing setting means for synchronizing with a fourth stroke phase of the fuel control apparatus for a combined intake type engine.