JPH0799111B2 - Intake air amount control device for internal combustion engine - Google Patents

Description

The present invention relates to an intake air amount control device for an internal combustion engine, which is effective for adjusting an intake air amount flowing through a bypass passage bypassing a throttle valve of the internal combustion engine. .

[Prior Art] Conventionally, in order to improve the fuel consumption efficiency of an internal combustion engine,
The engine is lightened and the idle speed is set low. In order to maintain such a low idle speed, the opening of the idle speed control valve installed in the bypass that bypasses the throttle valve of the internal combustion engine is adjusted to set the idle speed to the target idle speed. Feedback control is performed.

By the way, an internal combustion engine that performs feedback control so as to maintain the idle rotation speed low as described above has a transient operating state such as a transition from a racing state to an idle state, or a transition from a deceleration state to an idle state. ,
A sudden drop in rotation speed or engine stall is likely to occur. Therefore, it has been considered that when the decrease amount of the rotation speed is equal to or more than a predetermined value, the idle speed control valve is opened by a predetermined opening degree to increase the intake air amount. However,
When shifting from the deceleration state to the idle state, the rotation speed drops from a high value.Therefore, if the above control is performed, the intake air amount will increase before the rotation speed drops to a low value, and the engine speed will decrease. There was a problem that it caused large fluctuations in speed and engine stalls. As a measure against such a problem, for example, "a method for controlling the rotational speed of an internal combustion engine" (Japanese Patent Laid-Open No. 60-19934) has been proposed. That is, this is a technique of increasing the amount of air flowing through the bypass when the engine speed is equal to or lower than a predetermined value and the drop amount of the engine speed is equal to or higher than a predetermined value.

[Problems to be Solved by the Invention] However, in the above-described conventional technique, control for increasing the intake air amount is performed not only when shifting from the deceleration state to the idle state but also when shifting from the racing state to the idle state. Since it is performed, there is a problem that the rotation speed immediately after the racing state does not decrease immediately. This gave the driver a great deal of discomfort.

Further, as described above, there is also a problem that the intake air amount is not always properly increased, such as the intake air amount is increased immediately after the racing state, and the fuel consumption efficiency is deteriorated.

The present invention provides an intake air amount control for an internal combustion engine that smoothly reduces the rotational speed when the internal combustion engine transitions from a deceleration state to an idle state, and quickly reduces the rotational speed when transitioning from a racing state to an idle state. The purpose is to provide a device.

Configuration of the Invention [Means for Solving the Problems] The present invention made to solve the above problems, as illustrated in FIG. 1, is an intake air flowing through a bypass passage bypassing a throttle valve of an internal combustion engine M1. The intake air amount adjusting means M2 for adjusting the amount according to a command from the outside, the operating state detecting means M3 for detecting an operating state including at least the fuel supply cutoff state of the internal combustion engine M1, and the operating state detecting means M3 The determination means M4 that determines whether or not the duration of the fuel supply cutoff state is equal to or longer than a predetermined time and the determination means M4 determines that the duration is equal to or longer than the predetermined time. When it is determined by the first increasing means M5 that outputs a command to increase to the first intake air amount to the intake air amount adjusting means M2 and the determining means M4 that the duration is less than the predetermined time, Inhalation An internal combustion engine comprising: a second increasing means M6 for outputting a command to increase the air amount to a second intake air amount smaller than the first intake air amount to the intake air amount adjusting means M2. The gist is the intake air amount control device of the engine.

The intake air amount adjusting means M2 is for adjusting the intake air amount flowing through the bypass passage bypassing the throttle valve of the internal combustion engine M1. For example, if it is installed in a bypass,
It can be realized by a solenoid valve that opens and closes according to the time ratio of non-energization. Also, for example, it is installed in the bypass
It may be configured by a motor-driven flow rate control valve that changes the opening degree according to the value of the energized current or the number of applied pulses.

The operating state detecting means M3 is for detecting an operating state of the internal combustion engine M1 including at least a fuel supply cutoff state. For example, an idle switch for detecting the fully closed state of the throttle valve and a rotation speed sensor for detecting the rotation speed of the internal combustion engine M1 are provided, and fuel is supplied based on a flag set or a signal generated based on the above detection results. It can be configured to detect a blocking condition.

The determination means M4 is for determining whether or not the duration of the fuel supply cutoff state is a predetermined time or longer. For example, it can be realized by a timer that measures the duration and a comparator that compares the measured duration with a predetermined time. Here, the predetermined time is, for example, a time at which the fuel supply cutoff state continuation time immediately after the racing state of the internal combustion engine M1 and the fuel supply cutoff state continuation time in the deceleration state can be distinguished.

The first increasing means M5 outputs a command to increase the intake air amount to the first intake air amount when it is determined that the duration is equal to or longer than the predetermined time. Here, the first intake air amount is, for example, a relatively large intake air amount that is determined corresponding to the operating state of the internal combustion engine M1 in the decelerating state.

The second increasing means M6 outputs a command to increase the intake air amount to a second intake air amount smaller than the first intake air amount when it is determined that the duration is less than the predetermined time. It is a thing. Here, the second intake air amount is, for example,
This is a relatively small amount of intake air determined according to the operating state of the internal combustion engine M1 immediately after the racing state.

The determination means M4, the first increasing means M5, and the second increasing means M6 can be realized by, for example, independent logic circuits. Further, for example, a well-known CPU, ROM, RAM, and other peripheral circuit elements may be configured as a logical operation circuit, and each of the above means may be realized according to a predetermined processing procedure.

[Operation] As shown in FIG. 1, the intake air amount control device for an internal combustion engine of the present invention detects the internal combustion engine detected by the operating state detecting means M3.
When the determination means M4 determines that the duration of the fuel supply cutoff state of M1 is longer than or equal to the predetermined time, the first increasing means M5 adjusts the intake air amount by issuing a command to increase the intake air amount to the first intake air amount. When the determination means M4 determines that the duration is less than the predetermined time, the command for increasing the intake air amount to the second intake air amount smaller than the first intake air amount is output to the second intake air amount. The second increasing means M5 serves to output to the intake air amount adjusting means M2.

That is, if the duration of the fuel supply cutoff state is long,
If the deceleration state is changed to the idle state, the intake air amount is increased to the first intake air amount. On the other hand, if the duration is short, the racing state is changed to the idle state and the intake air amount is changed to the first intake air amount. The control is performed to increase the second intake air amount smaller than the intake air amount.

Therefore, the intake air amount control device for an internal combustion engine according to the present invention prevents a sudden decrease in the rotation speed of the internal combustion engine during the transition from the deceleration state to the idle state, and reduces the rotation speed during the transition from the racing state to the idle state. Work so as not to delay. The technical problems of the present invention are solved by the action of each component of the present invention as described above.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a system configuration of an engine intake air amount control device according to an embodiment of the present invention.

The intake air amount control device 1 for the engine is composed of an engine 2 and an electronic control device (hereinafter simply referred to as an ECU) 3 for controlling the engine 2.

The engine 2 forms a combustion chamber 7 from a cylinder 4, a piston 5 and a cylinder head 6, and an ignition plug 8 is arranged in the combustion chamber 7.

The intake system of the engine 2 includes an intake pipe 10 communicating with the combustion chamber 7 via an intake valve 9, a surge tank 11 provided upstream of the intake pipe 10 for absorbing pulsation of intake air, and the surge tank 11 Throttle valve 12 arranged on the upstream side of
Is equipped with. Further, the intake pipe 10 is provided with a bypass passage 13 that bypasses the throttle valve 12, and an idle speed control valve (hereinafter simply referred to as ISCV) whose opening is adjusted based on the control of the ECU 3 is provided in the bypass passage 13. 14) is installed.

On the other hand, the exhaust system of the engine 2 includes an exhaust pipe 16 that communicates with the combustion chamber 7 via an exhaust valve 15.

The fuel system of the engine 2 includes a fuel supply source 17a including a fuel tank and a fuel pump, a fuel supply pipe 17b, and a fuel injection valve 17 arranged in the intake pipe 10.

Further, the ignition system of the engine 2 distributes the high voltage generated by the igniter 18 to the ignition plugs of the respective cylinders by interlocking with an igniter 18 having an ignition coil for outputting a high voltage required for ignition and a crankshaft (not shown). It consists of a distributor 19 that supplies.

The intake air amount control device 1 for an engine includes an intake air pressure sensor 21, an air cleaner, as a detector, which measures an intake pipe pressure derived from a wake portion of a throttle valve 12 by a conduit 11a.
An intake air temperature sensor 22 provided inside 10a for measuring the intake air temperature, a throttle position sensor 23 for detecting the opening of the throttle valve 12 in conjunction with the throttle valve 12,
Water temperature sensor installed in the cooling system to detect the cooling water temperature
24, an oxygen concentration sensor 25 provided in the exhaust pipe 16 for detecting the residual oxygen concentration in the exhaust as an analog signal.

Further, inside the distributor 19, a rotation angle that also functions as a rotation speed sensor that outputs a rotation angle signal for every 1/24 rotation of the camshaft of the distributor 19, that is, for each integral multiple of the crank angle of 0 ° to 30 °. A sensor 26 and a cylinder discrimination sensor 27 that outputs a reference signal once for each rotation of the camshaft of the distributor 19, that is, for every two rotations of a crankshaft (not shown) are provided.

The signals from each of the above sensors are input to ECU3 and EC
U3 controls the engine 2.

As shown in FIG. 3, the ECU 3 is composed of a CPU 3a, a ROM 3b, a RAM 3c and a backup RAM 3d as a logical operation circuit, and an input / output port 3f and an input port via a common bus 3e.
Connected to 3g and output port 3h for external input / output. Intake pressure sensor 21, water temperature sensor 24, intake temperature sensor 22
And the detection signal from the throttle position sensor 23, buffers 3i, 3j, 3k provided for each sensor,
3m, and further input from the input / output port 3f to the CPU 3a via the multiplexer 3n and the A / D converter 3P. The detection signal of the oxygen concentration sensor 25 is sent via the buffer 3q and the comparator 3r, and the detection signals of the cylinder discrimination sensor 27 and the rotation angle sensor 26 are sent via the waveform shaping circuit 3s from the input port 3g to the CP.
Input to U3a. Further, the CPU 3a outputs a control signal from the output port 3h to the drive circuits 3t, 3u, 3v to inject the fuel injection valve 17,
Drives igniter 18 and ISCV14.

Next, the increase amount calculation process in the bypass intake air amount calculation process executed by the ECU 3 will be described based on the flowchart of FIG. This increase amount calculation process is executed as part of the bypass intake air amount calculation process, and
It is started with the start of and is repeatedly executed every 40 [msec].

First, in step 100, the throttle position sensor 2
Idle switch signal output from 3 is high level (O
N), and if affirmative, step 1
On the other hand, if negative determination is made, the process proceeds to step 230. In step 110, which is executed when the throttle valve 12 is in the fully closed idle state, a process of reading the value of the F / C flag is performed. The F / C flag is a flag that is set to a value 1 while the fuel supply is cut off and reset to a value 0 when the fuel is supplied. In the following step 120, based on the value of the F / C flag read in the above step 110, it is determined whether or not the fuel supply is being cut off. Proceed to step 130. In step 130, which is executed when it is determined that the fuel is being supplied, the process of resetting the time count value of the timer counter CFCUT to 0 is performed, and then the process proceeds to step 170.
On the other hand, in step 140 executed when it is determined that the fuel supply is being cut off, it is determined whether or not the time count value of the timer counter CFCUT is the reference time A (in the case of the present embodiment, 3 [sec] or more). Then, if an affirmative decision is made, the operation proceeds to step 160,
On the other hand, if a negative decision is made, the operation proceeds to step 150. In step 150, which is executed when it is determined that the fuel supply is being cut off and the reference time A has not yet elapsed, the value of 1 is added to the measured value of the timer counter CFCUT, and then step 170 is performed. Proceed to. On the other hand, in step 160, which is executed when it is determined that the reference time A has elapsed while the fuel supply is being cut off, after the process of setting the flow rate increase flag FQH to the value 1, the process proceeds to step 170. In step 170, it is determined whether or not the rotation speed decrease rate ΔNe is the determination value B (20 [rpm] / [40 [msec] in the present embodiment) or more, and if an affirmative determination is made, step 180 is performed.
If a negative decision is made, the operation proceeds to step 210. In step 180, which is executed when it is determined that the rotation speed has suddenly decreased, it is determined whether or not the flow rate increase flag FQH is set to the value 1, and if a positive determination is made, step 190
On the other hand, if a negative decision is made, the process proceeds to step 200.
In step 190 executed when the flow rate increase flag FQH is set to the value 1, that is, when the deceleration state is changed to the idle state, the ISCV opening increase command value QN is changed to
After performing the process of setting the multi-flow rate increase opening QH corresponding to the first intake air amount which is a relatively large flow rate, the increase amount calculation process is once ended. Then, in a subsequent process (not shown), the ISCV opening increase command value QN is added to the ISCV opening command value calculated in another process. The ISCV opening command value is a command value obtained according to the cooling water temperature detected by the water temperature sensor 24, or the current rotation speed and cooling obtained based on the signal from the rotation angle sensor 26. The command value obtained according to the deviation from the target speed set according to the water temperature, the command value set according to the load on the engine 2 by the auxiliary machinery, and the like are added.

On the other hand, in step 200 executed when the flow rate increase flag FQH is reset to the value 0, that is, when the racing state is changed to the idle state, the ISCV opening increase command value QN is set to the first intake air After performing the process of setting the small flow rate increase opening QL corresponding to the second intake air amount which is smaller than the amount, the present increase amount calculation process is once terminated, and is obtained by another process in the same manner as the above-described process. Add the above ISCV opening increase command value QN to the ISCV opening command value.

On the other hand, in step 210, which is executed when it is determined in step 170 that the rotational speed has not suddenly decreased, it is determined whether the ISCV opening increase command value QN is 0 or not. . The ISCV opening increase command value QN is still 0
In step 220, which is executed when the ISCV opening is not decreased,
After performing the process of reducing the QN by the decrease amount ΔQ, the present increase amount calculation process is once terminated, and the same process as above is performed.
Further, when it is determined in step 210 that the ISCV opening increase command value QN has decreased to 0, the process bypasses step 220 and the increase amount calculation process is temporarily terminated.

On the other hand, if it is determined in step 100 that the idle switch signal is at the low level (OFF), step 2
After proceeding to 30 and resetting the flow rate increase flag FQH to the value 0, this increase amount calculation processing is once terminated. After that, the bypass intake air amount calculation process including this increase amount calculation process is
It is repeatedly executed every [msec].

Next, an example of the above control will be described with reference to the timing charts of FIGS. 5 and 6. First, control when the racing state is changed to the idle state will be described with reference to FIG. The engine 2 shifts from the idle state to the racing state at time T1, and the idle switch signal changes from the high level (ON) to the low level (OFF) accordingly. Next, when returning from the racing state to the idle state at time T2, the fuel supply is cut off and the F / C flag is set to the value 1. At this time, since the load of the engine 2 is small in inertia only in the engine mechanism portion such as the flywheel, the rotation speed Ne starts to rapidly decrease. Therefore, at the same time T2, the rotation speed decrease rate ΔNe
Increases above the judgment value B. On the other hand, after the F / C flag is set to the value 1, since the reference time A has not yet elapsed, the flow rate increase flag FQH is reset to the value 0.
Therefore, the ISCV opening increase command value is set to the small flow rate increasing opening QL as shown by the solid line (steps 100, 110, 120, 14
0,150,170,180,200). At time T3 after the time t1 has elapsed from the time T2, the rotation speed Ne is the return rotation speed 1000 [rp
m.], the fuel supply is started and the F / C flag is reset to the value 0. Since this time t1 is shorter than the reference time A, the flow rate increase flag FQH remains reset to the value 0. Next, at time T4, the rotation speed decrease rate Δ
Ne is less than the judgment value B. Therefore, the ISCV opening increase command value is decreased by the decrease amount ΔQ as shown by the solid line, and the time T5
At 0, the rotation speed Ne also rapidly decreases to a value determined by the opening of ISCV according to the ISCV opening command value and stabilizes (steps 170, 210, 220). However, in the conventional technology, a large opening is set as the ISCV opening increase command value at time T2 as shown by the broken line. Therefore, even if the ISCV opening increase command value is decreased from the time T4 by the decrease amount ΔQ as shown by the broken line, the rotation speed Ne only gradually decreases as shown by the broken line, and from the time T5 of this embodiment. It was finally stable at time T6, which was delayed.

Next, the case of shifting from the deceleration state to the idle state will be described with reference to FIG. At time T11, the engine 2 shifts from the deceleration state to the idle state, and the idle switch signal changes from the low level (OFF) to the high level (ON) accordingly. At this time, the fuel supply is cut off and the F / C flag is set to the value 1. At this time, the load of the engine 2 includes the entire drive mechanism of the vehicle and has a large inertia, so the rotation speed Ne does not easily decrease. Eventually time T1
In 2, the rotation speed decrease rate ΔNe increases above the judgment value B. On the other hand, since the reference time A or more has elapsed after the F / C flag was set to the value 1, the flow rate increase flag FQH is set to the value 1. Therefore, at the same time T12, the multi-flow rate increase opening QH is set as the ISCV opening increase command value (steps 100, 110, 120, 140, 160, 170, 180, 19).
0). At time T13 after a lapse of time t2 from the time T11, the rotation speed Ne decreases to the return rotation speed 1000 [rpm], so fuel supply is started and the F / C flag is reset to the value 0. Since this time t2 is longer than the reference time A,
The flow rate increase flag FQH is set to the value 1. next,
At time T14, the rotation speed decrease rate ΔNe becomes lower than the determination value B. Therefore, the ISCV opening increase command value is decreased by the decrease amount ΔQ, reaches 0 at time T15, and the rotation speed Ne is rapidly decreased and stabilized (steps 170, 210, 220). After that, the above control is repeated.

In this embodiment, the engine 2 is the internal combustion engine M1 and the ISCV
14 correspond to the intake air amount adjusting means M2. Also, ECU3
And the process executed by the ECU 3 (step 110) is the operating state detection means M3, and the step (140, 160) is the determination means M4.
As a result, (steps 180, 190) function as the first increasing means M5, and (steps 180, 200) function as the second increasing means M6.

As described above, according to this embodiment, when the fuel supply cutoff duration of the engine 2 is the reference time A or longer, the ISCV opening increase command value is set to the multi-flow-rate increase value as if the deceleration state is changed to the idle state. Since it is set to QH, engine 2
By gradually decreasing the rotation speed of the engine, it is possible to effectively prevent the occurrence of engine stall and the deterioration of driving performance.

Further, the fuel supply interruption time of the engine 2 is the reference time A.
If it is less than 0, 220 from the racing state. After that, since the ISCV opening increase command value is set to the small flow rate increasing opening QL assuming that the engine has moved to the upper idle state, the engine speed can be quickly reduced to adapt to the driver's operation and cause discomfort. It is possible to drive without giving.

Further, when the racing state is changed to the idle state, appropriate bypass intake air amount control such as setting the ISCV opening increase command value to the small flow rate increasing opening QL is performed, so that the fuel consumption efficiency is also improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. .

As described in detail above, the intake air amount control device for an internal combustion engine according to the present invention controls the intake air amount that bypasses the throttle valve when the duration of the fuel supply cutoff state of the internal combustion engine is a predetermined time or longer. On the other hand, when the duration is less than the predetermined time, the intake air amount is increased to the second intake air amount which is smaller than the first intake air amount. Therefore, there is an excellent effect that the rotation speed of the internal combustion engine can be smoothly reduced at the time of shifting from the deceleration state to the idle state, and the rotation speed can be quickly reduced at the time of shifting from the racing state to the idle state.

Further, along with the above effect, the internal combustion engine can be smoothly operated in an excessive state, and an operating state that is also suitable for the driver's operation feeling can be realized.

Further, since the increase in the intake air amount that bypasses the throttle valve is reduced during the transition from the racing state to the idle state, the fuel consumption efficiency is also improved by the appropriate intake air amount control.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram conceptually illustrating the content of the present invention, FIG. 2 is a system configuration diagram of an embodiment of the present invention, and FIG. 3 is a block for explaining the configuration of the electronic control unit thereof. FIGS. 4 and 5 are flowcharts showing the same control, and FIGS. 5 and 6 are timing charts showing the manner of the control. M1 ...... Internal combustion engine M2 ...... Intake air amount adjusting means M3 ...... Operating state detecting means M4 ...... Judging means M5 ...... First increasing means M6 ...... Second increasing means 1 ...... Engine intake air amount control Device 2 ... Engine 3 ... Electronic control unit (ECU) 3a ... CPU 14 ... Idle speed control valve (ISCV)

Claims (1)

[Claims] 1. An intake air amount adjusting means for adjusting an intake air amount flowing through a bypass passage bypassing a throttle valve of an internal combustion engine according to a command from the outside, and an operating state including at least a fuel supply cutoff state of the internal combustion engine. The operating state detecting means for detecting, the determining means for determining whether or not the duration of the fuel supply cutoff state detected by the operating state detecting means is a predetermined time or more, and the determining means, the duration is a predetermined time or more If it is determined that the duration is a predetermined time, the first increasing means for outputting a command to increase the intake air amount to the first intake air amount to the intake air amount adjusting means, and the determining means. If it is determined that the second intake air amount is less than the first intake air amount, a second increase command is output to the intake air amount adjusting means to increase the intake air amount to a second intake air amount that is smaller than the first intake air amount. An intake air amount control device for an internal combustion engine, comprising: an adding unit.