JP2843913B2 - Idle speed learning control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed learning control method for controlling a valve control value by learning a valve control value during idle speed feedback control. 2. Description of the Related Art This type of idle speed learning control method is disclosed in
The one described in Japanese Patent Publication No. 58-158343 is known. Here, when the idle speed control is started, for example, when the engine is shifted from the load operation state to the idle operation state, the control value of the idle speed control valve as valve means for regulating the intake air amount of the engine, The learning value is corrected based on the deviation from the previous learning value. In this case, if the correction is set so as to increase the gain of the control value by feedback in order to speed up the convergence of the learning value, temporary disturbance during feedback may cause the correction. The learning value is disturbed. If the gain of the control value is set small in order to reduce the influence of the disturbance, the convergence of the learning will deteriorate. Accordingly, the present invention provides an idle speed learning control that enables a learning value close to a steady-state control value to be obtained at an early stage when the idle speed control is started, and prevents disturbance of the learning value due to disturbance. It seeks to provide a way. [Means for Solving the Problems] For this reason, the idle speed learning control method of the present invention
A valve means for regulating an intake air amount provided in an intake system of an engine, a control value of the valve means is learned during idle speed feedback control, and a learned value of the valve means is given to a next feedback control. In the above, after shifting to the idle state, at least one state of whether the actual engine speed is within the target speed range or the control value of the valve means is stuck to the upper limit or the lower limit of the set value continues for a predetermined time. If the learning condition is satisfied by setting a new learning value based on the previous learning value and the current control value of the valve means, the learning condition is not satisfied and the control value of the valve means is not learned. In the case of implementation,
The control value of the valve means at that time is set as a learning value. Therefore, if some of the above-mentioned set conditions such as the idle speed being within the target range are continuously satisfied for a predetermined time, it is determined that this is a stable steady state, and the previous learning value and With the current valve control value, the learning of the valve control value can be performed gently. Further, under the condition that the above-mentioned condition is not satisfied and the condition is not yet learned, by setting the valve control value at that time as the learning value, a value close to the true learning value can be quickly set as the learning value. . After the above condition is satisfied, the disturbance of the learning value due to disturbance is also avoided. Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an engine, and a water temperature sensor 2 for detecting a cooling water temperature is provided on one side of a cylinder of the engine. Further, an injector 3 is provided at a stage preceding the intake port of the engine, and an idle switch 5 is provided at a position of the throttle valve 4. A bypass 6 is provided in the intake pipe in parallel with the throttle valve 4, and an idle speed control valve (hereinafter referred to as an ISC valve) 7 is provided here as valve means for regulating an intake air amount of the engine. Have been. The control signal to the ISC valve 7 is given from the control circuit 8. In the drawing, reference numeral 9 denotes a crank angle sensor, 10 denotes an intake air temperature sensor provided upstream of the throttle valve 4, for example, provided in an air cleaner 11, 12 denotes a pressure sensor provided downstream of the throttle valve 4, and 13 denotes an exhaust system. was an O ₂ sensor. As shown in FIG. 2, the control circuit 8 includes a valve control value setting means 81 for the ISC valve 7, and the valve control value setting means 81 includes a learning value storage means 82.
Thus, the learning value of the ISC valve 7 learned during the previous feedback control is given. Further, the control circuit 8 is provided with an engine speed detecting means 83, which detects the engine speed from a signal detected by the crank angle sensor 9. Further, the output of the water temperature sensor 2 is input to a target engine speed setting means 90, and a target engine speed according to the coolant temperature is set. Then, the engine speed from the engine speed detecting means 83 and the target engine speed from the target engine speed setting means 90 are input to the valve control value setting means 81, and a feedback gain amount is set in accordance with the deviation therebetween. Calculate and set the valve control value. The signal from the engine speed detecting means 83 is also given to the learning condition detecting means 84. When the idle switch 5 is turned on, the learning condition detecting means 84 is supplied with the engine speed signal,
The control value of the ISC valve 7 is given from the valve control value setting means 81. The result is input to the learning mode switching means 85,
In the learning mode switching means 85, a method of setting a learning value of the ISC valve 7 is selected. If the actual idle speed is within the target range or the control value of the ISC valve 7 is stuck to the upper or lower limit of the set value,
If any one is satisfied, and if the above condition is satisfied within a predetermined time set by the timer 86, the learning value setting means 87 is operated to achieve normal learning of the valve control value. For example, an average value of the previous learning value and the current valve control value set by the feedback control by the valve control value setting means 81 is set as a new learning value, and the previous learning value stored in the learning value storage means 82 is set. Update the learning value.
If none of the above conditions is satisfied, it is determined whether or not the vehicle is in an unlearned state. By operating the setting control value setting means 88, the ISC valve control value set by the valve control value setting means 81 is fetched, set as a learning value as it is, and the stored value of the learning value storage means 82 is updated. In this way, the valve control value setting means 81 drives the driving means 89 with the learning value or the ISC valve control value that is fed back according to the deviation of the engine speed from the target engine speed.
The control value of the SC valve is controlled. The logic circuits of the learning condition detecting means 84 and the learning mode switching means 85 of the above embodiment are shown in FIG. Here, during feedback control of the idle speed, a signal of “H” is given from a to each of the AND gate circuits AND-1 to AND-4, and if the idle speed is within the target range, b The signal of "H" is supplied to the AND gate circuit AND-1. If the opening of the ISC valve is at the upper limit, a signal of “H” is given from c to the AND gate circuit ADN-2, and if the opening of the ISC valve is at the lower limit, d and the above AND gate circuit AN
The signal of “H” is given to D-3. When the opening degree learning has never been performed, the AND gate circuit AN is obtained from e.
An "H" signal is applied to D-4. Also, for a certain time,
When the signals a to d are maintained, an "H" signal is given to the AND gate circuits AND-5 and AND-6 from f. The output signals from the AND gate circuits AND-2 and AND-3 are supplied to an OR circuit OR-1, and the output therefrom is supplied to the AND gate circuit AND-6 and the AND gate circuit A
The output signal of ND-1 is applied to an AND gate circuit AND-5. The output signals of the AND gate circuits AND-5 and AND-6 are output to the learning value setting means 82 via the OR circuit OR-2. In addition, the AND gate circuit AND-
The output signal of 4 is output to the setting control value setting means 88.
FIG. 4 shows such a series of processes in a time chart. Here, at the first stage when the engine is switched from the load operation state to the idle operation state, the learning value learned during the previous idling is set as the initial value of the ISC valve control value, and the engine value is maintained until the learning condition is satisfied. The engine speed is fed back to the target engine speed, the set ISC valve control value is set as a learning value, and after the learning conditions are satisfied, the average value of the previous learning value and the current ISC valve control value Is updated as a new learning value. Next, a control routine in the control circuit 8 will be described with reference to FIG. In step S101, it is determined whether feedback control of the idle speed is being performed, for example, based on the on / off state of the idle switch 5. If the feedback control is not being performed, the control value learning of the ISC valve is not performed. If it is determined that the feedback control is being performed, first, in step S102, it is determined whether or not the engine speed is within a target range. If it is within the target range, the process proceeds to step S105. If not, then in step S103, it is determined whether or not the control value of the ISC valve is at the upper limit. If so, the process proceeds to step S105. If not, the process proceeds to step S104, where it is determined whether the control value of the ISC valve has reached the lower limit. Here, if it is stuck, the process proceeds to step S105.
Move to. In step S105, it is determined whether or not the idle speed has been within the target range for a predetermined time and whether or not the control value of the ISC valve has stuck to the upper limit or the lower limit for a predetermined time. Move to S201. If the above condition is satisfied, the process proceeds to step S106, where, for example, new learning value = (old learning value + ISC
Set the learning value of the ISC valve to be (valve control value) / 2. In step S201, it is determined whether learning of the control value after transition to the idle state has been performed.If not, in step S202, the ISC valve control value at that time is set as a learning value. Become. As can be understood from the above, the time position at which the learning condition is satisfied in FIG. However, in any case, when it is determined that learning has not been performed, convergence to a true learning value can be realized quickly. In the above embodiment, the control target of the valve control value is IS
Although the C-valve is used, the control method of the present invention is of course also applicable to idle speed control for a throttle valve. As described in detail above, the present invention distinguishes between the two states of whether or not the learning of the valve control value has been performed, and separates the logic for taking in the learning value. When shifting from the operating state to the idle operation state, the valve control value that is feedback-controlled is updated as a learning value until the learning condition is satisfied, and convergence to a true learning value can be achieved early. After the learning condition is satisfied, the value obtained by averaging the previous learning value and the valve control value is used as the new learning value, so that the learning value is changed slowly, and the fluctuation of the valve control value is not unnecessarily incorporated into the learning value. A stable learning value can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a block configuration diagram of a control circuit, FIG. 3 is a logic diagram, FIG.
FIG. 5 is a time chart of the idle rotation control, and FIG. 5 is a flowchart of the control system. 5 ... Idle switch, 7 ... ISC valve, 8 ... Control circuit, 9 ... Crank angle sensor, 81 ... Valve control value setting means, 82 ... Learning value storage means, 83 ... Engine speed detection means .. 84 learning condition detecting means 85 learning mode switching means 86 timer 87 control value correction amount setting means 88 setting control value setting means 89 driving means.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/00-41/40

Claims (1)

(57) [Claims] A valve means for regulating an intake air amount provided in an intake system of an engine, a control value of the valve means is learned during idle speed feedback control, and a learned value of the valve means is given to a next feedback control. In the above, after shifting to the idle state, at least one state of whether the actual engine speed is within the target speed range or the control value of the valve means is stuck to the upper limit or the lower limit of the set value continues for a predetermined time. If the learning condition is satisfied, a new learning value is set based on the previous learning value and the current control value of the valve means, and the learning condition is not satisfied and the learning of the control value of the valve means has not been performed. In this case, the control value of the valve means at that time is set as a learning value.