JPH0718372B2 - Idle speed control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an idle speed control device for an internal combustion engine.

BACKGROUND ART Certain prior art controls the idle speed of an internal combustion engine to a preset value.

In the prior art having such a configuration, it is not possible to adjust the idle speed, and therefore the preset speed may be inappropriate due to variations in the characteristics of the internal combustion engine. In such a case, a so-called engine stall that stops during the operation of the internal combustion engine is likely to occur.

Another traveling technique for solving this problem is to use a variable resistor and an analog-digital converter that converts its output into a digital value, and obtain an idle speed corresponding to the resistance value of the variable resistor. To control the internal combustion engine.

Problems to be Solved by the Invention In such a prior art, it is possible to adjust the idle speed to determine the optimum idle speed for each internal combustion engine. This new problem of the prior art requires electronic parts such as a variable resistor and its associated analog-to-digital converter, which is costly and requires the installation of such variable resistor and analog-to-digital converter. Must be devised, and the reliability may be reduced.

The object of the present invention is to increase the number of electronic components without increasing
It is an object of the present invention to provide an idle speed control device for an internal combustion engine, which can set the idle speed of the internal combustion engine to a desired value.

Means for Solving the Problem The present invention gradually changes the idle rotation speed by setting the rotation speed condition setting means for setting that the idle rotation speed is set and the condition setting of the rotation speed condition setting means. The rotation speed changing means, the means for detecting and storing the actual rotation speed when the rotation speed condition setting means is in the idle rotation speed setting condition, and the idle speed setting condition released by the rotation speed condition setting means, An idle speed control device for an internal combustion engine, comprising: means for controlling an idle speed to a speed stored in a storing means.

Operation According to the present invention, the rotation speed changing means gradually increases or decreases the idle rotation speed of the internal combustion engine by setting that the rotation speed condition setting means sets the condition for setting the idle rotation speed. And change. When the idle speed setting condition is set, the actual rotation speed is detected and stored by the storing means. After canceling the idle rotation speed setting condition by the rotation speed condition setting means, idle rotation is performed at the rotation speed stored in the storing means. In this way, the actual rotation speed when the idle rotation speed setting condition is canceled is set as the idle rotation speed that is the target value. In this way, the desired rotation speed can be set as the idle rotation speed.

Embodiment FIG. 1 is a block diagram of an embodiment of the present invention. A throttle valve 3, which is operated by an accelerator pedal or the like, is interposed in an intake pipe line 2 of the internal combustion engine 1. The intake pipe line 2 is provided with a bypass pipe line 4 in parallel with the throttle valve 3, and a flow control valve 5 is interposed in the middle of the bypass pipe line 4. During idle rotation, that is, when the accelerator pedal is not depressed, the opening degree of the throttle valve 3 is a predetermined minimum value. At this time, the idle speed of the internal combustion engine 1 can be adjusted by changing the opening degree of the flow rate control valve 5 and adjusting the flow rate of the air flowing through the bypass conduit 4. When the opening degree of the flow rate control valve 5 is increased and the bypass flow rate of air is increased, the idle speed of the internal combustion engine 1 can be increased. On the contrary, by closing the flow control valve 5, the idling speed can be reduced.

In order to set the condition for setting the idle speed, the switch SW1 is turned on, whereby a low level signal is input from the line 6 to the interface 8 of the control device 7. When the condition for setting the idle speed is cancelled, the switch SW1 is open, and at this time, the interface 6 gives a high level signal from the line 6. The power from battery 9 mounted on the car is
The ignition switch SW2 supplies the constant voltage circuit 10 with electric power, the electric power from the constant voltage circuit 10 is supplied to the processing circuit 11 and the random access memory 12, and the operation program of the processing circuit 11 is stored in the read-only memory.
Also given to 13. The power from the battery 9 is always applied to the other constant voltage circuit 14 so that the standby random access memory 15 is always energized. The standby random access memory 15 can hold the stored contents regardless of the switching mode of the ignition key SW2. The standby random access memory 15 stores the set idle speed, as will be described later. The rotation speed of the internal combustion engine 1 is
It is detected by the rotation speed detector 16. The detector 17 detects whether or not the air conditioner for cooling and heating the passenger compartment is operating. Further, there is provided a detector 18 for detecting whether the gear stage of the automatic transmission equipped with a torque converter or the like for transmitting power from the internal combustion engine 1 to the wheels is neutral or driving position. The outputs from these detectors 16 to 18 are given to the processing circuit 11 via the interface 8.

FIG. 2 is a waveform chart for explaining the operation of the embodiment shown in FIG. 1, and FIG. 3 is a flow chart for explaining the operation. Referring to these drawings, the ignition switch SW2 is turned on at step r1 in FIG. At step r2, it is judged whether or not the switch SW1 is conducting. To set the condition for setting the idle speed, the switch SW1 is turned on. As a result, the process moves from step r2 to step r3, and it is determined whether the count value of the timer T is the upper limit value T1. If so, the process proceeds to step r4, the count value of the timer T is set to zero, and the timer counts up to the upper limit value T1. This timer T
The upper limit value T1 of is about 2 seconds, for example. This upper limit T1
Is the time necessary and sufficient to calculate and obtain the average value of the rotational speed of the internal combustion engine 1 which is constantly changing, and the rotational speed N of the internal combustion engine 1 is controlled to the control target value N5 of the idle rotational speed. It has been selected in sufficient time. The switching mode of the switch SW1 is as shown in FIG. 2 (1), and the target value of the rotation speed of the internal combustion engine 1 under the idle speed setting condition is shown in FIG. 2 (2). As shown, it gradually changes with time, whereby the actual rotational speed N of the internal combustion engine 1 is controlled as shown in FIG. 2 (3). Under the idle speed setting condition, the target value is shown in Fig. 2 (2) as described above, and is a predetermined value AN higher than the minimum value M by n1.
From then on, the value decreases by a predetermined value n0 every time T1. The minimum value M is described in the ROM 13 and is a value N1 to N4 that varies depending on the operating conditions of the air conditioner 17 and the automatic transmission 18. The increment that is the difference from the minimum value MA when the current control target value is N5 is indicated by reference numeral N0.

At step r5, the value obtained by subtracting the rotation speed n0 for one step from the increment N0 is changed to a new increment N0 which is the difference from the next target value. At step r6 it is determined if the set increment N0 is negative, if not then go to step r8 and when increment N0 becomes negative the value N0 at step r7.
Is zero.

At step r8, the actual speed of the internal combustion engine 1 is detected by the detector 16
The value N is stored in the storage area B. At step r9, based on the output from detector 17,
It is determined whether or not the air conditioner indicated by reference symbol A / C is operating, and when the air conditioner is at rest, the process moves to step r10 to determine whether the transmission is in a neutral state where no power is transmitted. If so, the process proceeds to step r11 to store a predetermined value N1 in the store area A. Step r1
In 2, the stored contents of the store area B are transferred to the store area NE1 of the standby random access memory 15 and stored.

In step r10, when the gear position of the transmission is not neutral, that is, when the driving position is reached, the process moves to step r13 to store a predetermined value N2 in the store area A, and in step r14 the store area B
The contents of is transferred to the store area NE2 of the standby random access memory 15.

When it is determined in step r9 that the air conditioner is operating, it is determined in step r15 whether the gear position of the transmission is neutral, and when it is not neutral, that is, when the vehicle is in the driving position,
Move to step r16. At step r16, a predetermined value N3 is stored in the store area A, and at step r17, the contents of the store area B is transferred to the store area NE3 of the standby random access memory 15.

When it is determined in step r15 that the shift speed is neutral, a predetermined value N4 is stored in the store area A in step r18, and the contents of the store area B are transferred to the store area NE4 of the standby random access memory 15. .

In this way, the air conditioner 1 is operated by steps r9 to r19.
Store area N corresponding to the operating conditions of 7 and automatic transmission 18
The idle speed will be stored in E1 to NE4.

At step r20, the sum of the contents of the store A and the value N0 is set as the control target value N5 of the idle speed. In step r21,
It is judged whether this value N5 exceeds the actual rotational speed N, and if it exceeds, the opening degree D of the flow control valve 5 is increased by one step d1.
Just reduce and go back to step r2. Further, in step r21, when the value N5 stored in step r20 is equal to or less than the actual number of revolutions N, the process proceeds to step r23 and the opening degree D2 of the flow control valve 5 is increased by one step d2. Then return to step r2. In this way, the actual rotation speed N is controlled so as to reach the rotation speed set in step r20.

When the idle speed setting is completed, switch SW
Cut off 1 to cancel the idle speed setting condition. As a result, the process moves from step r2 to step r24, and the value N0 is set to the initial setting value n1. In steps r25 to r27, as in steps r9, r10, and r15 described above, cases are classified according to the outputs of the detectors 17 and 18 in accordance with the driving conditions. In steps r28 to r31, the idle speeds NE1 to NE4 set in each of the above cases are used as the value N5, and
Move to r21. In this way, the opening degree of the flow control valve 5 is controlled, and the idle speed of the internal combustion engine 1 is set to the set value NE1.
~ NE4.

FIG. 4 is a flow chart for explaining the operation of another embodiment of the present invention. The process proceeds from step s1 to s2, and it is determined whether the switch SW1 is conducting. Step s2
If the switch SW1 is turned on at, and thus it is determined that the condition for setting the idle speed is satisfied, the process proceeds to step s3, and it is determined whether the count value of the timer T has reached the upper limit value T1. If there is, the process proceeds to step s4 and the count value of the timer T is reset to zero. Steps s5 to s11
Is the step r9 of the embodiment described in connection with FIG. 3 above.
Corresponds to ~ r19 respectively. In this way, the rotation speeds NE1 to NE4 of the detectors 17 and 18 for each operation state are set to the predetermined value N1.
It is set to a value obtained by subtracting the rotation speed n0 for one step from N4. Steps s12 to s14 are the steps r21 in FIG.
.About.r23 and steps s16 to s23 correspond to steps r24 to r31 in FIG. 3, respectively. In this way, the set rotational speeds NE1 to NE4 are gradually changed and set in accordance with the time until the switch SW1 is turned on again after being turned on.

As still another embodiment of the present invention, the target value of the internal combustion engine 1 may be periodically changed after the switch SW1 is turned on. Although the target value is gradually decreased with the passage of time after the switch SW1 is turned on in the above-mentioned embodiment, the target value is gradually increased as another embodiment of the present invention. Good.

The invention is not only implemented in connection with the internal combustion engine of a motor vehicle, but can also be implemented extensively for controlling the idle speed of internal combustion engines used in other applications.

As described above, according to the present invention, the idle speed is adjusted to an optimum value for each internal combustion engine without requiring electronic parts such as the variable resistor and the analog-digital converter in the above-mentioned prior art. It becomes possible to do. Thereby, the cost can be reduced and the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation, FIG. 3 is a flow chart for explaining the operation, and FIG. 4 is another embodiment of the present invention. 4 is a flowchart for explaining the operation of the example. 1 ... Internal combustion engine, 2 ... Intake line, 3 ... Slot valve, 4 ... Bypass line, 5 ... Flow control valve, 7 ... Control device, 8 ... Interface, 11 ... Processing circuit , 12 ...
… Random access memory, 13 …… Read only memory, 15 …… Standby random access memory, 16 ……
Rotation speed detector, 17,18 …… Detector, SW1 …… Switch, SW
2 …… Ignition switch

Claims (1)

[Claims] 1. A rotation speed condition setting means for setting a condition for setting an idle rotation speed, and a rotation speed changing means for gradually changing the idle rotation speed according to the condition setting of the rotation speed condition setting means. The rotation speed condition setting means detects and stores the actual rotation speed when the idle rotation speed setting condition is met, and the rotation speed condition setting means releases the idle rotation speed setting condition and then stores it in the storing means. And a means for controlling the rotational speed of the internal combustion engine to control the idle rotational speed of the internal combustion engine.