JPH0726583B2 - Engine idle speed control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle rotation speed control method for controlling a rotation speed of an automobile engine at a desired speed.

[0002]

2. Description of the Related Art In order to control the idle speed during warm-up to a target value according to the cooling water temperature of the engine, or the connection state of an on-vehicle load driven by an engine such as a compressor of an automobile air conditioner to the engine In order to control the idle speed to a target value according to the above, the actual engine speed is detected and the amount of auxiliary air that bypasses the throttle valve or the throttle valve is detected according to the difference between the target value and the actual speed. It has been proposed to adjust and control the feedback control amount of the rotational speed feedback control target such as the opening degree.

[0003]

By the way, in such a control device, when the aging of the control device occurs, for example, when the opening area changes due to adhesion of dust to the valve for adjusting the auxiliary air amount, etc. However, there are cases where the actual rotation speed does not easily reach the target value, but with respect to such secular change, if the feedback control amount is large, that is, the control response is quick, the idle rotation speed changes rapidly. There is a problem of hunting in an extreme case due to poor stability.On the contrary, the feedback control amount is small, that is, if the control response is slowed, for example, when switching from normal load operation to idle operation, idle rotation It takes time for the speed to converge to the target value, that is, the rotation speed is too high to deteriorate fuel economy, or too low to cause engine stall. Plus Mora die.

Therefore, an object of the present invention is to provide an idle rotation speed control method capable of controlling the idle rotation speed to a target value with high response and accuracy.

[0005]

In order to achieve the above object, in the present invention, it is determined whether or not the engine is in an idle state. Intake control that adjusts the intake air amount to the engine so that the actual rotation speed when the engine is idle matches the target value by the control amount that is set by integrating the comparison result with the actual rotation speed of A method of driving an engine to control an idle speed of an engine, wherein the control amount is compared with a predetermined value, and a value that is integrated according to the comparison result is readable and writable and stored even when the engine is stopped. A memory capable of holding contents is stored as rotation speed correction information, and the intake air adjustment hand is stored based on the rotation speed correction information and the control amount stored in the memory. By driving the is characterized by controlling the idle speed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. In FIG. 1, 1 is an internal combustion engine, 2 is an intake system, and 3 is a throttle system (balf). Reference numeral 4 denotes an idle switch for detecting the fully closed state of the throttle valve 3. 5 is an actuator for controlling the amount of auxiliary air that bypasses the throttle valve 3, 51 is an electromagnetic coil, the magnetic force of which is determined by the output current of the control circuit 30.

Reference numeral 52 denotes a magnetic material, which is connected to the valve 53, and adjusts the opening of the valve 53, that is, the amount of auxiliary air bypassing the throttle valve 3 by balancing the output currents of the springs 54 and 55 and the control circuit 30. is doing.
Reference numerals 6 and 7 are air passages. Reference numeral 9 is a rotation sensor that outputs an ignition device interruption signal as an engine rotation signal.

FIG. 2 is an electric circuit diagram showing the control circuit 30. A DA conversion circuit 301 receives a signal from the rotation sensor 9, that is, an intermittent signal IG of the ignition device, and converts a frequency signal into an analog voltage. A function generation circuit 302 receives a signal from a water temperature sensor 303a that detects the engine cooling water temperature and a signal from a cooler switch 303b that switches on / off of an electromagnetic clutch of a compressor of an air conditioner for a vehicle as an on-vehicle load to input warm-up operation. An analog voltage that determines the target value of the idle rotation speed at the time and the target value of the idle rotation speed when the cooler as the load is turned on is generated and supplied to the comparator 304.

The comparator 304 compares the output voltage of the DA conversion circuit 301 and the output voltage of the function generating circuit 302 to determine the set rotation speed, that is, the magnitude of the target value and the actual rotation speed, and respectively, high level and low level. The voltage of the level is output to the integrating circuit 305. The integrating circuit 305 is the operational amplifier 30.
6, the resistor 307, the capacitor 308, the analog switch 31 that is turned on and off by the signals of the idle switch 4
9 and integrates in the increasing / decreasing direction according to the output of the comparator 304, and when the idle switch 4 is off, the analog switch 319 is closed to output a constant voltage. Reference numeral 309 denotes an adding circuit, which is an operational amplifier 3
10 and resistors 311, 312, 313, and adds the output of the integration circuit 305 and the output of the learning control circuit 314 described later.

The learning control circuit 314 includes a microcomputer 315 including an A / D converter, a readable / writable non-volatile memory (that is, a readable / writable memory that can retain its stored contents even when the engine is stopped) 31.
6, a D / A converter 317 for D / A converting the output of the microcomputer 315, and a comparator 318. This learning control circuit 314 receives a control amount of a value corresponding to the difference between the target value and the actual value of the idle speed, that is, the integrated output of the integrating circuit 305 in this embodiment, and the value related to this component output, that is, The output of the comparator 318 that compares the integrated output with the set voltage is compared with the nonvolatile memory 316.
Is stored as rotation speed correction data.

FIG. 3 is a flow chart for schematically explaining the function of the microcomputer 315 of the learning control circuit 314, which will be described below. The engine is started and the processing routine is started. First, in step 1001, it is determined whether or not the idle switch 4 is on, that is, the throttle valve 3 is closed and the idle operation is being performed. When the idle switch 4 is turned on, the engine cooling water temperature T from the water temperature sensor 303a is fetched as digital binary information in step 1002,
Moreover, the engine rotation speed N from the rotation sensor 9 is fetched as digital binary information.

In the next step 1003, the water temperature correction data F = F ^m _n of the corresponding address stored in the non-volatile memory 316 shown in FIG. 4 is read. This F
^m _n is the cooling water temperature in the map shown in FIG.
The second is the data of the address corresponding to the n-th engine rotation speed. In the next step 1004, it is determined whether or not the cooler switch 303b is on, that is, whether or not a compressor for a vehicle air conditioner as a load is connected to the engine. When the cooler switch 303b is on, the load is determined in step 1005. Read correction data f = f ₁ from the non-volatile memory 316. Cooler switch 303b
When is off, step 1006 reads f = f ₂ from the memory 316.

Next, in step 1007, the comparator 31
8 is at a high level, that is, whether the integrated output of the integrating circuit 305 is at a predetermined level or higher, and the comparator 318
Is high, an integration process of adding a predetermined value ΔF to the water temperature correction data F (= F ^m _n ) is executed in step 1008, and the data is updated by writing it in the corresponding address of the nonvolatile memory 316. In step 1009, the load correction data f is similarly integrated by adding a predetermined value Δf, and the write data is updated in the corresponding address of the memory 316. When the comparator 318 is at the low level, the process proceeds to step 1010, the integration process of subtracting the predetermined value ΔF from the data F (= F ^m _n ) is executed, the write data is updated in the corresponding address of the memory 316, and then, Step 1011
In the same manner, the data f is also subjected to the integration process of subtracting the predetermined value Δf, written in the corresponding address of the memory 316, and the data is updated.

In the next step 1012, the correction value A is obtained by adding the water temperature correction data F and the load correction data f.
Is calculated, and the correction value A is set to D in the next step 1013.
Output to the -A converter 317, and the DA converter 31
In step 7, the correction value A is converted into an analog amount. In the next step 1014, the process waits for a time ΔT in order to achieve the above-described processing at every predetermined cycle, and after the time ΔT has elapsed, step 1001
Return to and repeat the above process. When the idle switch 4 is not on, the routine proceeds to step 1015, where a constant correction value Ac is output to the DA converter 317, and then the routine proceeds to step 1014.

Next, the operation of the above configuration will be described. A target value representing a target rotation speed according to the engine cooling water temperature and the connection state of the cooler as the engine load is output from the function generating circuit 302. The comparator 304 compares the target value with the actual rotation speed, and outputs a high or low level signal according to the magnitude. When the engine is idle, that is, when the idle switch 4 is on, the analog switch 319 of the integrating circuit 305 is open, and the integrating circuit 305 integrates and outputs according to the determination signal of the comparator 304.

When the engine speed is equal to or higher than the target value, the comparator becomes high level, the integrated output decreases, and the adding circuit 30
The output of 9 also decreases, and the output to the actuator 5 is small. The actuator is configured to increase the bypass air amount when the supplied output current increases and decrease the bypass air amount when the supplied output current decreases. Therefore, when the engine rotation speed is equal to or higher than the target value, the actuator 5 reduces the bypass air amount. , Reduce the rotation speed.

Further, the output of the learning control circuit 314 is supplied to the adding circuit 309, and from this learning control circuit, the correction value obtained by adding the water temperature correction data F and the load correction data f as described above. A, that is, the past rotational deviation correction amount corresponding to the current water temperature state and the load state is output. Therefore, the feedback control based on the difference between the current rotational speed and the target value is the same as the past feedback control from the addition circuit 309. The correction signals for both learning control based on the correction amount under the condition are added and output.

By the way, as described above, when the control amount in the feedback control based on the difference between the current rotation speed and the target value is calculated, the difference is obtained by the integration processing by the integration circuit 305. The control amount is a value that changes according to the secular change in the vicinity of the engine 1 and the valve 53. That is, due to the secular change, the valve 53 corresponding to the required air amount of the engine for the target value at that time and the current to the actuator 5
If the opening area of is deviated from the reference at the time of design, the current rotation speed will deviate to a value that is always higher than the target value or a value that is lower than the target value. Becomes

Therefore, the control amount gradually changes with a time constant based on the integration constant of the integration circuit 305 in the direction of eliminating the deviation. Then, in response to this change, the comparator 318 of the learning control circuit 314 outputs a high level or low level output to the microcomputer 315.
The water temperature correction data F and the load correction data f are also increased / decreased by the integration processing by the above-described processing, and the correction value A obtained by adding the both changes to a value that eliminates the above-described deviation.

Therefore, the output of the adder circuit 309 is centered on the correction value A for compensating for the above deviation, and the integrating circuit 305 is provided.
It becomes a value that fluctuates up and down in the vicinity according to the integrated output of. That is, the fluctuation range of the integrated output can be small.

In the present embodiment, the correction value A is used as the water temperature correction data F and the load correction data f as the memory 316.
Since it is stored in, the fluctuation range of the integrated output can always be kept small. Therefore, even if the feedback control amount is not increased, the rotation speed at the time of engine idling can be controlled with high responsiveness and high control accuracy. In particular, when the load operation of normal running is switched to the idle operation state, or when the connection state of the engine load such as the cooler is switched during the idle operation, the correction value A corresponding to the idle operation after the switch is performed. Immediate output from the learning control circuit 314 to the adder circuit 309 makes it possible to control the idle rotation speed to a target value with a response that is unprecedented.

Further, the engine is cooled and the temperature of the cooling water is low, and the engine is warmed up from the idle state where the engine is controlled to a high target rotational speed to the load operation. During the load operation, the engine warms up and the cooling water temperature is high. When the state shifts to the idle state after the state, the low target rotation speed is set, but as described above, in the present embodiment, the water temperature correction data F corresponding to the water temperature and the rotation speed is provided. Since the water temperature correction data F corresponding to the water temperature and the rotation speed at that time are used, when only one correction data is provided, the correction data is slightly controlled until the learning control reaches a value suitable for the operating state. However, since the correction data F corresponding to the operating state is immediately reflected in the control, the controllability is significantly improved.

When the engine is in a load operation such as normal running, the idle switch 4 is opened and the integration circuit 305 outputs a predetermined voltage because the analog switch 319 is closed. The learning control circuit 314 also outputs a constant value Ac. As a result of outputting the correction signal of, the actuator 5 supplies a constant amount of bypass air to the engine.

Although the compressor of the air conditioner (cooler) for automobiles has been described as the load in the above embodiments, a hydraulic motor for power steering or the like can be similarly considered. Further, the actuator 5 is the throttle valve 3
Although the control of the amount of air that bypasses is shown, it goes without saying that the same control can be applied to the control of the opening degree of the throttle valve 3. Further, the correction information for the engine cooling water temperature is stored as a map that is distinguished by the rotation speed and the cooling water temperature as shown in FIG. 4, but it is of course possible to store it as a map that is distinguished by the intake negative pressure and the cooling water temperature. is there.

[0025]

As described above, in the method of the present invention, the control amount fluctuates according to the secular change of the engine and the like, and therefore the rotational speed correction information changes with the lapse of time in response to the change of the control amount. Is stored in the memory as a value capable of compensating for the deviation of the control system of the idle rotation speed including the engine due to the secular change, for example, the deviation of the flow rate characteristic due to dust adhesion of the intake air adjusting means. Become. Then, by controlling the idle rotation speed by the control amount according to the comparison result of the target value and the actual rotation speed and the rotation speed correction information, the rotation speed correction information for compensating for the deviation of the control system is obtained. Since the control amount is changed by an insufficient amount and the actual rotation speed is controlled so as to match the target value, the fluctuation range of the control amount can be made sufficiently small. Even when the load operation is switched to the idle operation, the rotation speed can be controlled responsively to the target value without increasing the control amount, and it is not necessary to increase the control amount. Can be controlled.

Further, since the rotational speed correction information is readable and writable and stored in the memory that can retain the stored contents even when the engine is stopped, even if the engine is stopped and restarted, the previous engine The rotation speed correction information set at the time of operation is stored and held. Therefore, the fluctuation range of the control amount can be constantly reduced, so that stable idle rotation control can always be realized.

In addition, the result of comparison between the target speed and the actual value is integrated to obtain a control amount for feedback control, and this control amount is compared with a predetermined value, and integration is performed based on the comparison result. Since the value obtained by the above is learned as the rotation speed correction information, the rotation speed correction information is mainly intended to compensate for the deviation of the drivability due to a long period of time, which is different from the above-mentioned control. Since the amount is mainly intended to absorb driving fluctuations in a relatively short period other than that, it is necessary to have corresponding integral characteristics when determining both during actual engine operation. This becomes possible, and optimal feedback control and learning control can both be achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the control circuit shown in FIG.

FIG. 3 is a flowchart for explaining a schematic function of the microcomputer of FIG.

FIG. 4 is a map stored in the non-volatile memory shown in FIG. 2 for explaining the present invention.

[Explanation of symbols]

 9 rotation sensor 30 control circuit 302 function generating circuit 314 for determining target value 314 learning control circuit 316 non-volatile memory

Claims (1)

[Claims] It is determined whether the engine is in the idle state, and when the engine is in the idle state, the comparison result between the target value of the idle rotation speed and the actual rotation speed at the time of idle is integrated to set the control amount of the engine. A method for controlling an idle rotation speed of an engine by driving an intake air adjusting means for adjusting an intake air amount to an engine so that an actual rotation speed at the time of idling coincides with the target value. The value that is compared with the value, and the value that is integrated according to the comparison result,
The memory is readable and writable and can retain the stored contents even when the engine is stopped, and is stored as rotation speed correction information, and the intake air adjustment means is driven by the rotation speed correction information and the control amount stored in the memory. Then, the engine idle speed control method is characterized by controlling the idle speed.