KR100194176B1 - Idle speed control of engine - Google Patents

Abstract

The present invention changes the cycle of feedback control according to the magnitude of the rotational deviation between the actual engine speed and the target idle speed to solve the problem of overshoot and responsiveness delay caused by the short and long period of the control cycle. will be.

When the ECU 9 incorporating the microcomputer detects the idling state of the engine 1 at the output from the idle sensor 8, the ECU 9 enters the output from the rotation speed sensor 7 and the ECU 9. The rotation speed deviation with the preset target idle speed is calculated, and if the rotation speed deviation is less than the first determination value, the feedback control is not executed. When the rotation speed deviation becomes the first determination value or more, the feedback is performed in the first cycle. In this feedback control, if the rotation speed deviation becomes equal to or greater than the second determination value, the feedback control is started in a second period shorter than the first period.

Description

Idle speed control of engine

The present invention relates to an idle rotation speed control device that performs feedback control so that an actual idle rotation speed is converged to a target idle rotation speed in an engine.

Conventional technology

For example, Japanese Patent Application Laid-Open No. 2-14979 sets a feedback control value according to the deviation between the actual engine speed and the target idle speed, and controls the amount of intake air supplied to the engine according to this control value. An idle rotation speed control device for controlling feedback of the engine speed of the engine to the target idle rotation speed is specified.

However, in the above-described control apparatus, for example, in order to execute feedback control at every control cycle at a predetermined timing, for example, if the control cycle is short, the actual engine speed is overshooted for a predetermined target idle speed. On the contrary, if the control period is set longer, the response time until the actual engine speed reaches the target idle speed is slow, and as a result, the driver's (drivability) decreases, and more There was a problem that it would lead to engine stall. In other words, in the above-described control apparatus, since only the feedback control value is switched in accordance with the rotational speed deviation in a constant control period T, the load of the engine into which the load with small electric consumption shown in FIG. 6 is small and in FIG. As shown, in the case where the load of the engine to which the electric consumption is added is large, the timing of starting the feedback control has the same feedback control value for both because the rotation speed deviation is the same as ΔNe for both of the time A. Is set. Then, as shown in FIG. 7, when the load is large, the next update timing is after a predetermined control period T, and there is a possibility that engine stall occurs between the control period T from the time A. FIG.

Therefore, in order to solve the above problems, the present invention changes over the period of feedback control according to the magnitude of the rotational deviation between the actual engine speed and the target idle speed, resulting in overshoot and responsiveness caused by short and long periods of the control period. It is an object of the present invention to provide an engine idle speed control device capable of eliminating the problem of delay and improving driver reliability and preventing engine stall.

Means to solve the problem

When the engine of claim 1 is idle, the amount of intake air of the engine is controlled by a comparison output between the preset target idle speed and the actual engine speed so that the actual engine speed becomes the target idle speed. An idle rotation speed control device for feedback control at each control cycle based on timing includes first comparison means for comparing a rotation speed deviation between the target idle rotation speed and an actual engine rotation speed and a first predetermined determination value, and the rotation. A second comparison means for comparing the number deviation and a second predetermined determination value larger than the first determination value, and a determination output means that the most significant deviation in the first comparison means is larger than the first determination value. It means that the feedback control is executed every first period T1, and the rotation speed deviation in the second comparing means is larger than the second determination value during the feedback control. It is characterized in that it includes switching means for a period immediately starts the feedback control for each first period (T1) than the second period (T2) of the short predetermined by the judgment output.

According to claim 1, if the engine speed is in the idle state when the speed deviation ΔNe is less than the first determination ΔNe value, no feedback control is executed, and the rotation speed deviation ΔNe is equal to or greater than the first determination value ΔNe1 (ΔNe ≧ ΔNe1). ), The feedback control is executed in a predetermined first period T1, and during this feedback control, when the engine speed is large due to the rotational deviation? Ne starting the feedback control in the second period T2. As described above, when the rotational speed difference ΔNe becomes equal to or greater than the second determination value ΔNe2, the driver reliability can be improved by shortening the next update timing by switching the cycle of feedback control from the first period T1 to the second period T2. The engine stall can be prevented.

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

2 is a flowchart of idle rotation speed control of the embodiment;

3 is a flowchart of a timer of the embodiment.

4 is a timing diagram of the embodiment.

5 is an explanatory view of the operation of the embodiment;

6 is an explanatory view of the operation when the conventional load is small.

7 is an explanatory view of the operation when the conventional load is large.

Explanation of symbols for main parts of the drawings

1: internal combustion engine 2: intake pipe

3: Throttle Valve 4: ISC Valve

5: air floor sensor 6: inject

7: RPM sensor 8: idle sensor

9: electronic control unit (ECU) 9a: first comparison means

9b: second comparison means 9c: cycle switching means

10: Load information from various sensors

Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 5. Fig. 1 is a block diagram showing an internal combustion engine controller including idle speed control (ISC control). In this figure, reference numeral 1 denotes an internal combustion engine consisting of a four-cycle engine, and 2, air is introduced into the internal combustion engine 1. 3 is a throttle valve for controlling the amount of air introduced into the intake pipe 2 in relation to an accelerator pedal (not shown) operated by a crew member, and 4 is an internal combustion engine when all of the throttle valves 3 are closed. ISC valve for adjusting the bypass air amount of the intake pipe 2 to the output from the electronic control unit 9 (hereinafter referred to as ECU) 9, which includes a microcomputer, which will be described later when 1) is idle, and 5 is internal combustion. An airflow sensor that detects and converts an intake air amount of the engine 1 and outputs the converted electrical signal to the ECU 9, 6 is an output from the ECU 9 between the internal combustion engine 1 and the throttle valve 3. Injecting fuel into the intake pipe 2 located at 7 denotes a rotational speed sensor which detects the rotational speed of the internal combustion engine 1 and outputs the converted electrical signal to the ECU 9, and 8 denotes a closed state of the throttle valve 3, that is, the idle of the internal combustion engine 1. It is an idle sensor which outputs the electrical signal which detected and converted the state to ECU9.

The ECU 9 includes a smoke control section and an idle rotation speed control section. The fuel control section controls the fuel injection amount to the injector 6 by the amount of intake air from the airflow sensor 5. The idle speed control unit outputs a control signal to the ISC valve 4 by various load information 10 such as an idle sensor 8 and other water temperature sensors (not shown), and sends the control signal to the suction pipe 2. Adjust the pass air volume.

In addition, the idle rotation speed control unit includes a first comparison means 9a, a second comparison means 9b, and a period switching means 9c. The first comparing means 9a is a rotation speed deviation ΔNe (ΔNe) between the actual engine speed Ne of the internal combustion engine 1 detected by the rotation speed sensor 7 and the preset target idle speed Neobj. = | Neobj-Ne | is compared with the 1st judgment value (DELTA) Ne1 preset. The second comparing means 9b compares the rotational speed deviation ΔNe with a preset second determination value ΔNe2. The period switching means 9c has a feedback control period that is shorter than the predetermined first period T1 based on the comparison result in the first comparison means 9a and the comparison result in the second comparison means 9b. The idle speed control signal is output to the ISO valve 4 by switching to the second predetermined period T2.

The first determination value ΔNe is data set to prevent excessive feedback control, and is usually set at about 30-50 rpm, and the rotation speed deviation ΔNe is synonymous with a dead band of ΔNe1 or more (ΔNe≥ The data determined to start the feedback control when ΔNe1) is set is data which does not depend on the operating state of the engine such as, for example, the transition from the deceleration state to the idle state.

The second determination value [Delta] Ne2 is data set for small feedback control because engine stall is prevented from occurring when the load of the internal combustion engine 1 is large during feedback control.

Reference numeral 11 is an air filter for filtering the air sucked into the suction pipe (2).

Next, the idle rotation speed control operation in the ECU 9 will be described in accordance with the flowchart of FIG. 2.

The processing in Fig. 2 is executed by the main routine processing of the microcomputer in the ECU 9. In step 201, the rotation speed deviation ΔNe between the actual engine speed Ne of the internal combustion engine 1 and the target idle speed Neobj is calculated. In step 202, the value of the second timer determines whether or not the switching determination timing is performed in the feedback control period. When the second timer? 0, it is determined by the switching determination timing, and the flow advances to step 203. In step 203, it is determined whether or not the cycle of feedback control is to be switched. In other words, when ΔNe is less than the second determination value ΔNe2, the cycle of feedback control is not switched. Therefore, the flow advances to step 206. When ΔNe is equal to or greater than the second determination value ΔNe2, the flow proceeds to step 204 to switch the period of the feedback control. In step 204, the first timer is reset to zero, and the flow proceeds to step 205. FIG. In step 205, the second timer is preset to a predetermined second period T2 shorter than the predetermined first period T1 of feedback control.

Here, the first timer indicates the first period T1 of feedback control. In addition, the second timer indicates the feedback control period switching determination timing and indicates the second period T2 of feedback control when? Ne is equal to or larger than the second determination value? Ne2.

Since both the first timer and the second timer are decremented every predetermined time as shown in the flowchart of Fig. 3, it means that the predetermined time has elapsed when the timer value is zero.

Subsequently, at step 206, it is determined whether or not the timing for starting feedback control is denied based on the value of the first timer. When the first timer? 0, it is determined that it is not the timing to start the feedback control, the process proceeds to step 210, and the process ends. When the first timer = 0, it is determined that the feedback control timing is reached, and the flow proceeds to step 207. In step 207, it is determined whether or not the feedback control is actually executed. That is, if ΔNe calculated above is less than the first determination value ΔNe1, it is determined that the feedback control condition is out of step, and the process proceeds to step 210 to end the present process. If it is equal to or more than the first determination value? Ne1, it is determined that the feedback control condition is satisfied, and the flow proceeds to step 208. In step 208, the value of the first timer is preset to the first period T1, and the flow proceeds to step 209. In step 209, the process proceeds to step 210 after the feedback control is performed.

4 is a diagram showing an actual feedback control operation in the above-described flow chart processing. In FIG. 4, a represents the actual engine speed Ne of the internal combustion engine 1, and Neobj in the figure is the target idle speed. b represents the rotational speed difference (DELTA) Ne between Ne and Neobj, (DELTA) Ne1 is a 1st determination value and (DELTA) Ne2 is a 2nd determination value in a figure. c denotes the operation of the second timer in the idle heater control in the microcomputer in the ECU 9, and d denotes the operation of the first timer in the idle revolution control in the microcomputer in the ECU 9. The operation is shown. e denotes a cycle of feedback control during idle rotation control in the microcomputer in the ECU 9, where T1 is a first cycle and T2 is a second cycle. f indicates the timing of starting the feedback control during the idle rotation speed control in the microcomputer in the ECU 9.

In the idle state, when the rotation speed Ne of the internal combustion engine 1 is overshooted than the target idle rotation speed Neobj, the rotation speed deviation ΔNe occurs as shown in b. If ΔNeΔNe1, feedback control is not executed, and both the first timer and the second timer remain as zero. Subsequently, when the conditions of? Ne?? Ne1 are established at the times t1 and t8, the feedback control is executed immediately, and the first timer is preset in the first period T1. Therefore, when the transition is made under the condition of? Ne1?? Ne? Ne2 as at time t9, the feedback is controlled at the time of the first timer = 0, that is, at the first period T1. Subsequently, if the condition of? Ne?? Ne2 is established as at time t2, and the second timer is 0, the first timer is reset to 0, so that feedback control is executed at that time. Thereafter, a first period T1 is preset in the first timer, and a second period T2 is preset in the second timer.

Further, although the relationship of T1? T2 is established between the first period T1 and the second period T2 of the feedback control, when the second timer = 0, the first timer is cleared immediately. Therefore, the period of feedback control is determined by the operation cycle of the first timer, but when the condition of ΔNe ≧ ΔNe2 is established, the operation cycle of the first timer is apparently coincident with the second timer operation cycle, and the second cycle T2 is performed. Feedback control can be started.

That is, according to the present embodiment, when the internal combustion engine 1 is in the idle state, if the rotation speed deviation ΔNe is less than the first determination value ΔNe1 (ΔNeΔNe1), the feedback control is not executed, and the rotation speed deviation is If ΔNe is equal to or larger than the first determination value ΔNe1 (ΔNe ≧ ΔNe1), feedback is performed at a predetermined first period T1, and during this feedback control, ΔNe is equal to or greater than the second determination value ΔNe2 ( When ΔNe ≧ ΔNe2, feedback control is started in a predetermined second period T2 shorter than the first period T1.

Therefore, as shown in Fig. 5, even when the engine is loaded with a large load of electricity consumption, when the rotation speed difference ΔNe becomes ΔNe2 or more, the period of the feedback control is the first period T1 to the second period T2. ), And the next update timing can be shortened to prevent engine stall.

For example, when the hand lamp is turned on, the amount of charge of the battery mounted on the vehicle operating as the internal combustion engine 1 decreases, and a load is applied to the internal combustion engine 1 so that the generator mounted on the vehicle starts power generation. The rotation speed of the internal combustion engine 1 falls. Thus, when the rotation speed deviation? Ne becomes equal to or greater than the first determination value? Ne1 (? Ne?? Ne1), feedback control is started to control the actual engine speed Ne to match the target idle speed Neobj. Run In this case, when the load applied to the internal combustion engine 1 is small, the feedback control is executed in the first period T1, and the internal combustion engine 1 is controlled at the desired rotational speed. In order to prevent the divergence of the control system, this first period T1 employs a time of about 1 second. When the load having a large power consumption is inputted, the rotation speed of the internal combustion engine 1 increases, so in this embodiment, the rotation speed deviation ΔNe is greater than or equal to the second determination value ΔNe2 (ΔNe ≧ ΔNe2). In this case, it is possible to prevent the engine stall from occurring by making the period of feedback control shorter than the first period T1.

According to the invention of claim 1, in the idle state of the engine, the overshoot and the responsiveness delay which are raised by switching the control period long and short in accordance with the rotational deviation between the actual engine rotational speed and the target idler rotational speed. The problem can be solved, and the driver's ability can be improved, and engine stall can be prevented.

Claims (1)

When the engine is in the idle state, the amount of intake air of the engine is controlled by the comparative output between the preset target idle rotational speed and the actual engine rotational speed so that the actual engine rotational speed is set to be the target idle rotational speed. In the idle rotation speed control device for feedback control for each control cycle based on the timing, A first comparison means for comparing the rotational deviation between the target idle rotational speed and the actual engine rotational speed and a predetermined first determination value, and comparing the rotational deviation and a second predetermined determination greater than the first determination value. Feedback control is executed for each predetermined first period T1 by the second comparing means and the determination output which means that the rotation speed deviation in the first comparing means is larger than the first determination value, and during the feedback control, Period switching means for immediately starting feedback control every predetermined second period T2 shorter than the first period T1 by a judgment output indicating that the rotational speed deviation in the second comparing means is greater than the second determination value. Idle speed control device of the engine, characterized in that provided with.

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