JPH0436039A - Idling speed control device of engine - Google Patents

Abstract

PURPOSE:To adjust engine speed to desired speed during loaded operation just after a load is applied to an engine and prevent the adjustment from being delayed by constantly maintaining a control parameter amount at its optimal value as a result of learning, the control parameter amount being corrected correspondingly to the load when the load is applied to the engine during idling operation. CONSTITUTION:The control parameter of an engine 1 is computed by a means 3 according to a state parameter detected by a means 2 and a predetermined expression. The speed of the engine 1 is controlled by a means 4 according to this parameter. The amount by which the control parameter is corrected when the loaded condition of the engine 1 is detected by a means 6 is stored in a means 7. Actual engine speed by the control parameter corrected according to a control parameter correction amount during loaded idling operation of the engine 1 is compared by a means 8 with desired engine speed during loaded idling operation. The control parameter correction amount is computed according to the result of the comparison and a value stored in the correction amount storage means 7 is renewed by a means 9 according to the computed value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine idle speed control device, and in particular, when the vehicle is stopped and the engine is idling, it can be used to control the engine idle speed, for example, an air conditioner compressor or a generator. The present invention relates to a device for optimally controlling the idle speed of a vehicle engine to which a load is applied to rotate the engine.

Although the present invention is particularly suitably used for controlling vehicle engines, it is widely applicable to engines to which a load is applied or not applied in an idling state.

[Prior Art] A widely known technique is to perform feedback control on engine control parameters (for example, intake air amount) in order to adjust the idle speed of the engine to a target idle speed.

Also, the target rotation speed is set higher than the target rotation speed when no load is applied to the engine, for example when a load is applied to drive the generator when the compressor for the air conditioner or the defogger switch is turned on. It is also known that

Here, when a load is applied during idle rotation, it seems that simply changing the target rotation speed will adjust the target idle rotation speed to the target idle rotation speed under load, but in reality, the engine stops when the load is applied. Moreover, if only feedback control is used, it will take time to adjust to the target rotation speed under load.

Therefore, a technique disclosed in Japanese Patent Publication No. 63-29100 has been proposed. With this technology, when it is detected that a load has been applied to the engine, the control parameters are corrected by a predetermined amount to prevent the engine from stopping, and to feedback control to the target rotation speed under load in a short time. I am considerate.

[Problems to be Solved by the Invention] However, in the conventional technology described above, the amount of correction of the control parameter is fixed at a predetermined value. This value is normally set to be the optimum value for changing the target rotational speed under no load to the target rotational speed under load, but since there are variations from engine to engine, it is not necessarily the optimum value for the engine in question. Furthermore, if engine characteristics change over time, they may gradually deviate from the optimum value.

Furthermore, the load for driving an air conditioner compressor may vary depending on the season, and in this case as well, it is not guaranteed that the predetermined value is the optimum value.

Therefore, even if a loaded state is detected and the control parameters are corrected by a predetermined amount, the resulting engine speed will not be the target speed under load, and the engine speed will be adjusted to the target speed by further feedback control. It takes time for this to occur, and during this time fuel is wasted or the necessary output cannot be obtained.

Therefore, the present invention aims to realize an engine idle speed control device that can control the engine speed to the target speed under load immediately after the load operation is detected.

[Means for Solving the Problem] The above problem is solved by a system whose outline is shown in FIG. means 3 for calculating control parameters of the engine 1 based on a predetermined formula; and means 4 for controlling the engine and the rotation speed of the engine 1 based on the calculated control parameters; means 6 for detecting the presence or absence of a load applied to the engine 1; means 7 for storing an amount by which the control parameters are to be corrected when a loaded state is detected by the detection means 6; During idling operation, the actual engine rotation speed when the control parameters are corrected based on the control parameter correction amount;
A means 8 for comparing the target engine rotation speed during idle operation with load, and a correction amount of the control parameter is calculated based on the comparison result of the comparison means 8, and the calculated value is used as a stored value in the correction amount storage means 7. This problem is solved by an engine idle speed control device comprising a system having means 9 for updating the engine speed.

According to the above system, if the target idle speed under load is not achieved as a result of detecting a load and correcting the control parameters, the amount of correction is learned to increase or decrease, and the target idle speed is achieved. The amount of correction required is calculated. Then, the subsequent control parameters are corrected based on this newly determined correction amount. Therefore, the amount of correction is optimally determined for each engine. Furthermore, even if the engine characteristics or load characteristics change over time, the amount of correction is always maintained at the optimum value by following it. As a result, when a load is applied during idling operation, the corresponding correction amount becomes the optimum value, and the engine speed is adjusted to the target rotation speed under load immediately after the load is applied to the engine. This solves problems such as wasted fuel or insufficient power.

[Example] Next, an example that embodies the present invention will be described. Second
The figure shows the system configuration of this idle speed control device.
FIG. 3 shows the signal processing system.

The engine 1 is provided with an intake passage 12, and the amount of intake air is determined by a throttle valve 1 that opens and closes in conjunction with the accelerator pedal.
Adjusted by 1. A throttle valve 1 is installed in the intake passage 12.
An inlet passage 13 is provided that bypasses the air intake passage 1, and the amount of intake air therein is adjusted by an auxiliary air adjustment valve 4a. When the accelerator pedal is not depressed, the throttle valve 11 substantially completely closes the intake passage 12, and the amount of intake air during idling is determined by the opening degree of the auxiliary air adjustment valve 4a. Therefore, the idle speed of the engine 1 is basically determined by the opening degree of the auxiliary air regulating valve 4a. Therefore, in this embodiment, the opening degree of the auxiliary air regulating valve 4a corresponds to the control parameter. Note that this auxiliary air adjustment valve 4a is used to turn on/off the drive current flowing to the solenoid coil.
The degree of opening can be adjusted by the off time ratio, that is, the duty ratio. In addition, the opening degree of the auxiliary air regulating valve 4a may be adjusted by a step motor.

This engine l includes an idle switch 2a that is turned on when the throttle valve 11 is in the idle position, and an intake passage 1.
2, a crank angle sensor 2C that outputs a pulse wave in synchronization with the rotation of the crankshaft of the engine 1 by a predetermined angle, a water temperature sensor 2d that detects the cooling water temperature of the engine 1, etc. Sensors are attached, and state parameters of the engine 1 are detected by these sensors 2a, 2b, 2c, and 2d.

The detected values of these state parameters are input to the engine control unit ECUIO. Also connected to the ECUIO are an air conditioner switch 6a that is turned on while the air conditioner is working and the compressor is being driven, and a defogger switch 6b that is turned on while the defogger is energized and the generator is being rotated. Further, the ECUIO is connected to the auxiliary air regulating valve 4a and the injector 14, and can control these.

The signal processing system mainly consisting of the ECUIO is configured as roughly shown in FIG. Namely, the idle switch 2a, the air conditioner switch 6a, and the default switch 6b.
The on/off signals such as the above are converted into high/low data by the level correction circuit 21 and can be input to the CPU 22. Analog signals generated from the intake pressure sensor 2b and the water temperature sensor 2d are appropriately amplified by a level correction circuit 23, and then converted into digital signals by an analog-to-digital converter 24, which can be input to the CPU 22.

In addition, the pulse wave of the crank angle sensor 2C is generated by the waveform shaping circuit 2.
After the waveform is shaped in step 5, it can be input to the CPU 22. In addition, the CPU 22 has an RO that stores programs.
M26 and a RAM 27 used for data calculation are connected. Further, the CPU 22 can control the opening degree of the auxiliary air regulating valve 4a via the drive circuit 28, and can control the opening/closing of the injector 14 via the drive circuit 29.

In the ROM 26, when the idle switch 2a is on and the air conditioner switch 6a and the default switch 6b are off,
That is, during idle operation with no load, the time interval of the pulse wave of the crank angle sensor 2C and the signal of the water temperature sensor 2d are input, and these are calculated based on a certain formula to set the control parameters, that is, the auxiliary air adjustment valve 4a. A program is stored that calculates the duty ratio that determines the opening degree. That is, the control parameter calculation means 3 is constituted by the program stored in the ROM 26, the CPU 22 controlled by the program, and the RAM 27 used in the calculation processing of the CPU 22. Then, the CPU 22 outputs a control signal to the drive circuit 28 based on this calculation result, whereby the opening degree of the auxiliary air adjustment valve 4a is controlled to the calculated value, and the idle speed of the engine at no-load is controlled. Ru.

That is, the CPU 22, the drive circuit 28, and the auxiliary air adjustment valve 4.
A constitutes a rotation speed control means 4. Note that a program for feedback controlling the engine speed may be added as necessary. The CPU 22 also calculates the optimum fuel amount based on state parameters detected by the intake pressure sensor 2b and the like, and outputs a control signal to the drive circuit 29 based on this result to control the injector 14.

The air conditioner switch 6 is stored in the ROM 26 by the CPU 22.
a. A program for reading the on/off state of the defogger switch 6b is stored, thereby forming a means 6 for detecting whether or not a load is applied to the engine 1.

In addition, at least a part of the RAM 27 is a backup RAM whose memory is not erased even when the engine is not in operation due to a backup power source, and contains the control parameters, that is, the duty ratio that determines the opening degree of the auxiliary air regulating valve in this embodiment. The amount to be modified can be memorized. That is, this backup RAM constitutes the control parameter modification amount storage means 7. Note that the ROM 26 includes the CPU 22.
A program for calculating the amount of correction and storing it in the backup RAM is stored, and the updating means 9 is constituted by this program. Also stored is a program that reads the amount of correction stored in the backup RAM and uses this to correct the control parameters.

Note that the target idle speed under load is stored in advance in the ROM 26, and the actual engine speed calculated by the CPU 22 from the time interval of the pulse wave from the crank angle sensor 2C is stored in the ROM 26. A program is stored that compares the target idle rotation speed under load. Comparing means 8 is constituted by these.

Next, a series of processing procedures executed by the portion of the program stored in the ROM 26 that is related to the present invention will be explained with reference to FIG.

Since this process involves a large load during air conditioner operation, a process is executed to correct the control parameters or update the amount of correction during air conditioner operation.

In step Sl, when the idle switch 2a is turned on, it is determined from the time interval of pulse waves from the crank angle sensor 2C whether or not the engine rotation speed is below a predetermined number.

If the idle switch 2a is not on, the accelerator pedal is depressed and the vehicle is not in an idle state.

Further, even if the idle switch 2a is on, the engine speed may be higher than a predetermined engine speed, and this occurs when the vehicle is in a deceleration state. In this case, the counter CAC that measures the time from when the air conditioner switch is turned on during idling should be zeroed out, and the learning correction coefficient MGK learned from the feedback control tendency when the engine is not loaded should be finalized. Let the correction coefficient be Mx. This Mx is determined as an increase/decrease coefficient of the duty ratio that determines the opening degree of the auxiliary air control valve. This will be explained later.

When it is detected at S1 that the engine is not decelerating and is in a so-called normal idle state, it is determined at S2 whether the air conditioner switch 6a is on.

If it is not ON, it is determined that no load is being applied to the engine. In this case, the counter CAC that measures the time since the air conditioner switch was turned on during idling as described above is re-initialized in S5).
Furthermore, the control parameter correction amount MAC is set to zero (S
6). Since there is no load here, there is no need to modify it according to the load.

Next, in step S14, the no-load target rotation speed stored in the ROM 26 is compared with the actual engine rotation speed calculated from the time interval of the pulse wave from the crank sensor 2C, and the no-load rotation speed calculated by the CPU 22 is calculated. A correction coefficient MFB for control parameters during idling operation is determined (S14).

This MFB is also determined as a correction coefficient for the duty ratio of the auxiliary air regulating valve 4a. As a result, according to the duty ratio corrected by MFB, the engine speed is adjusted to the target no-load idle speed. In step S18, the tendency of MFB obtained in this way is extracted and the learning correction coefficient MG is
Calculate K. For example, if the control parameter calculated by the CPIJ 22 is always small and the MFB calculated in step S14 is always on the increasing side, MGK is updated to the increasing side. As a result, the value of the control parameter calculated by the CPU 22 corrected by the MGK comes to match the value adjusted to the target rotation speed, and the feedback correction in step 814 becomes a very fine feedback correction near the target rotation speed. The idle speed during no-load is accurately and quickly adjusted to the target value.

Note that, as mentioned above, in step 817, step 818
The learning correction coefficient calculated by is used as the final correction coefficient. For this reason, auxiliary air is taken in even when the engine is not idling, but this allows the amount of intake air to be corrected in all operating conditions, providing good operating performance with no variation from engine to engine even when the engine is not idling. It turns out.

Next, idle rotation speed control under load, which is the subject matter of the present invention, will be explained.

First, when the air conditioner switch is turned on during idle rotation, the correction amount MAC stored in advance in the backup RAM is read out as described above (S3). Then, 1 is added to the counter CAC. Steps S1 to 815
Since the processes from S17 to S17 are repeatedly executed at fixed time intervals, a value proportional to the time since the air conditioner switch was turned on during idling is stored in the CAC.

Step S7 executes a process of determining whether a first predetermined period of time has elapsed since the air conditioner switch was turned on. Here, the first predetermined time is set to the time until the result of starting to correct the intake air amount based on the correction amount MAC in step 815 appears in the engine speed. 1st
Since it is not possible to determine whether the correction amount MAC is the optimum value until the predetermined time has elapsed, steps 89 to 813 described later are skipped and step 815 is executed. That is, step 814
A correction amount MAC is further added to the feedback correction coefficient MFB and learning correction coefficient MGK calculated in steps 818 and 818 to determine a correction coefficient for the duty ratio to be applied to the auxiliary air regulating valve 4a. The engine speed is adjusted to the no-load target speed by the first two corrections, and the final correction amount MAC is used to increase the engine speed in accordance with the air conditioner load.

Next, when it is determined in step S7 that a first predetermined time period or more has elapsed, the time period is compared with a second predetermined time period in S8. Here, the second predetermined time is set as the time necessary for updating or learning the correction amount MAC, and if more than this has elapsed, 814
The feedback control of 89 to 813 is not performed. The correction amount MAC should be the correction amount immediately after the air conditioner starts operating, and if the second predetermined time period or longer elapses, the optimum correction amount itself will change, and the learning of the optimum correction amount MAC immediately after the air conditioner is turned on is necessary. It is not suitable for

Now, S9 to S13 are processes for updating or learning the correction amount MAC, and in step S9, the actual engine speed NE is compared with the maximum value of the target idle speed under load, and if it is greater than or equal to the maximum value, The correction amount MAC is reduced by a predetermined value α. If it is less than the maximum rotation speed, it is compared with the minimum value of the target idle rotation speed under load in 811, and if it is less than the minimum value, the correction amount MAC is increased by a predetermined value α. The new correction amount MAC calculated in this way is stored in the backup RAM (S13), and in the next process, the updated correction amount MAC is read and compared in step S3. Then, in step S15, a duty ratio correction coefficient for determining the opening degree of the auxiliary air regulating valve 4a is determined based on the updated correction amount MAC.

Note that the target maximum rotational speed and the target minimum rotational speed at the time of loading in step S9 and Sll are stored in the ROM 26 in advance. In this embodiment, the correction amount MAC is prevented from being updated too frequently by giving a range to the target rotational speed, but the range can be adjusted appropriately, and there is no need to provide a range in practice.

Next, a second embodiment embodying the present invention will be described with reference to FIG. This is a case where both the air conditioner switch 6a and the default switch 6b are on (hereinafter referred to as case 1).
), the magnitude of the load is different when only the air conditioner is on (hereinafter referred to as case 2) and when only the differential off is on (hereinafter referred to as case 3), so the optimal correction amount for each case is learned or updated. I try to do that.

Also, during the same process, C(1) is the name of the variable that counts the elapsed time since both the air conditioner and the differential were turned on.
(2) is used as a variable name for counting the elapsed time since only the air conditioner was turned on, and C(3) is used as a variable name for counting the elapsed time since only the defogger was turned on.

When it is determined in step 5IOI that it is not in the idle state, it is the same as in the first embodiment, and each counter is initialized in step 8124 to prepare for the next time measurement.
Then, the opening degree correction coefficient of the auxiliary air regulating valve 4a is set as the learning value MGK, and the intake air characteristics in the entire area are corrected. Further, if the air conditioner is off in step 5102 and the defogger is off in step 5104, that is, if the engine is in a no-load idling state, each counter is cleared to zero in step 5120 in preparation for the next time measurement.

Next, in step 5121, the correction amount MEL for the load is
Let be zero. Here, MEL corresponds to MAC in the first embodiment. Steps 5I22 and 8123 respectively correspond to 314 and 818 in the first embodiment, and their meanings are exactly the same, so their explanation will be omitted.

Now, steps 5102, 103, and 104 are steps for differentiating cases, and if both the air conditioner and the default filter are on, A=1 is set in step 5105.

Further, if only the air conditioner is on, A=2 in 8107. Furthermore, if only the defogger is on, A=3 at 5IO9. Steps 5106, 108 and 110 are means for zeroing counters for cases other than each case. For example, in step 810G, except for C(1), C(2) and C(
3) is zeroed out. Step 5111 is a time counting process, for example, after step 5105 is executed, step 5
When llll is executed, C(1)←-C(1)+1
processing is executed. Step 5112 is a process of searching for one of the load correction amounts M(1), M(2), and M(3). Here, M(1) is the amount of correction for case I, M(2) is the amount of correction for case 2, and M
(3) is the correction amount for case 3, which is calculated in 3117 or 5119.

Steps 5113 and 8114 are 87 and 88 in the first embodiment.
This process corresponds to , and its explanation will be omitted.

Now, step 5115 is a process to search for the target idle rotation speed under load, THI) is the maximum allowable rotation speed when both the air conditioner and the defogger are ON, and T2(1) is the maximum allowable rotation speed when the air conditioner and the defogger are both ON. The minimum allowable rotation speed, TI (2) is the maximum allowable rotation speed when only the air conditioner is on, T 2 (2) is the minimum allowable rotation speed when only the air conditioner is on, and TI (3) is the maximum allowable rotation speed when only the air conditioner is on.
T2(3) is the maximum allowable rotation speed when only the defogger is ON. All of these are stored in the ROM26.

Steps 3116, 117, 118, 119°126 are 89. of the first embodiment. 10. 11. This is a process equivalent to 12°13. And M updated like this
(A) (A is either l or 2.3) as MEL (
S127), this updated MEL in step 8128
The amount of correction for the opening degree of the auxiliary air regulating valve 4a is calculated.

According to this embodiment, both the air conditioner and the default gas are turned on.
Under a total of three load conditions, when the load is N and when only one of them is ON, each correction amount is learned and updated to always become the optimum correction amount.

Furthermore, according to this embodiment, since the configuration can be configured to have both a learned value when no load is applied and a learned value when loaded, the correction range for each learned value can be reduced, so that correction can be performed using only one learned value. It also has the advantage of being able to perform processing with finer resolution and higher accuracy than when using conventional methods.

``Effects of the Invention According to the present invention, when a load is applied during idling operation, the amount of control parameters that are modified in response to the load are always kept at the optimum value as a result of learning, so that the engine Even if there are variations in characteristics or changes over time in engine characteristics or load, this is learned and the optimum correction amount for the engine in question is determined and corrected.As a result, the load is applied. Immediately after that, the target rotation speed under load is adjusted, and there is no delay in adjustment.

Therefore, the idle speed can be controlled extremely well without temporarily causing problems such as wasted fuel or insufficient output.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the concept of the device of the present invention, Fig. 2 is a diagram showing the configuration of the device according to the embodiment, and Fig. 3 is a diagram showing the signal processing system of the device in Fig. 2. , FIG. 4 is a diagram showing an example of processing performed by this device, and FIG. 5 is a diagram showing another example of processing performed by this device. [Explanation of main symbols; see Figure 1]

Claims (1)

[Claims] An engine 1, means 2 for detecting state parameters of the engine, and calculating control parameters for the engine 1 based on the state parameters detected by the detection means 2 and a predetermined formula. means 3 for controlling the engine based on the calculated control parameters to control the rotation speed of the engine 1; means 6 for detecting the presence or absence of a load applied to the engine 1; means 7 for storing an amount by which the control parameter is to be modified when a loaded state is detected by the means 6; means 8 for comparing the actual engine speed according to the parameter with the target engine speed during idle operation with load; calculating the correction amount of the control parameter based on the comparison result of the comparing means 8; An engine idle speed control device comprising a system comprising means 9 for updating the stored value of the correction amount storage means 7 with the value.