JPH0219296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a learning control device for the idle speed of an internal combustion engine.

<Prior art> As an idle speed control device for an internal combustion engine, for example, as shown in FIG. 4, an idle control valve (ISC valve) 3 is provided in the middle of an auxiliary air passage 2 that bypasses a throttle valve 1. Some models control the idle speed by adjusting the auxiliary air passage. The idle control valve is of a rotary type, and pulse signals are sent to a valve-opening coil and a valve-closing coil (not shown) in an inverted state, and the opening degree is adjusted according to the duty ratio of the pulse signals. be done. Note that 4 is an SPI fuel injection valve, 5 is a hot wire air flow meter, and 6 is a blow-by gas recirculation pipe.

By the way, the duty ratio of the pulse signal to the idle control valve is the control value calculated by the following formula:
Determined by ISCdy. The unit of this control value is expressed in (%), and the valve opening coil is
Output as the percentage of time that it is ON.

ISCdy=ISCtw+ISCet+ISCfb Here, ISCtw is a basic control value dependent on cooling water temperature (hereinafter referred to as water temperature), ISCet is various correction amounts for air conditioner, D range, and acceleration/deceleration correction, and ISCfb is idle speed feedback control (ISC), which will be described later. )
This is the amount of feedback correction for .

Regarding the feedback control of the idle rotation speed, the target rotation speed depends on the water temperature detected by the water temperature sensor, and the actual rotation speed detected by the rotation angle signal from the crank angle sensor or the signal from the ignition coil. (hereinafter referred to as the actual rotation speed), and if there is a difference, the control value at that time is corrected to achieve the target rotation speed. For this reason, a feedback correction amount ISCfb is defined. ing.

The value of the feedback correction amount ISCfb is changed by integral control or proportional-integral control to achieve stable control. In other words, the target rotation speed and the actual rotation speed are compared, and if the actual rotation speed is lower (higher) than the target rotation speed, the feedback correction amount ISCfb is
increases (decreases) little by little.

By the way, the open loop duty (feedback correction amount) corresponding to the basic control value ISCtw (or the addition value of this and the correction amounts ISCtr and ISCet)
If the rotation speed obtained by the control value ISCdy (when ISCfb is the reference value) completely matches the target rotation speed, the feedback correction amount ISCfb will remain at the reference value, so feedback control is not necessary. However, in reality, the throttle chamber is blocked.
Feedback control is performed because the correlation may deviate due to variations in parts.

However, if the correlation between the open-loop duty and the target rotational speed is off, when the actual rotational speed deviates from the target rotational speed, feedback control is performed to compensate for the deviation in the correlation between the open-loop duty and the target rotational speed. It takes time for the rotation speed to be corrected, that is, for the rotation speed to settle down to the original target rotation speed. This may lead to the engine stalling or the like. In addition, in order to solve this problem, if the integral constant of integral control is increased when setting the feedback correction amount ISCfb, hunting, over (under) shooting, etc. will occur, resulting in unstable idle rotation and engine stall due to drop in rotation. There are some problems that may arise.

Therefore, by correcting the open-loop duty, that is, the basic control value through learning and correlating it with the target rotation speed, it is possible to eliminate correlation deviations and quickly control the idle rotation speed. The applicant of the present invention has already filed an application for a system that improves the stability of idle rotation by making it possible to reduce the integral constant at the time of engine rotation.

However, when starting the engine (particularly when starting at a low temperature) and immediately after starting, friction is large due to oil viscosity and lubrication delays, making it difficult for the rotational speed to increase.As shown in Figure 5, the integral of feedback correction is The correction amount is large, and if this value is learned, it will have an adverse effect on the learning correction amount in the stable state that was learned until the previous time, and as a result, the effectiveness of learning control will be reduced.

<Problems to be Solved by the Invention> The present invention has been made in view of the above points, and is capable of continuously performing good learning control after startup without adversely affecting the learning correction amount during startup. The purpose is to solve the above problems.

<Means for solving the problem> For this reason, the present invention, as shown in FIG. basic control value setting means A that sets the basic control value, and feedback correction amount setting means B that sets the feedback correction amount by integral control by comparing the engine target rotation speed set based on the engine operating state and the actual rotation speed. , a learning correction amount search means D for searching the learning correction amount stored in the map C of the RAM according to the engine operating state, and adding a predetermined percentage of the deviation amount from the reference value of the feedback correction amount to the learning correction amount. a learning correction amount correcting means E for setting a new learning correction amount and updating the data of the same engine operating state in RAM; a means F for detecting the starting state of the engine; and a means F for detecting the starting state of the engine, and the elapsed time after starting the engine. a learning stop means H that stops the data update operation of the learning correction amount at the time of starting and for a certain period of time after the starting; a control value calculation means I for calculating a control value of the duty ratio of the pulse signal;
The configuration includes pulse signal output means J that outputs a pulse signal of a duty ratio based on the calculated control value to the idle control valve.

In the second aspect of the invention, the predetermined time period after startup for stopping the learning correction amount data update operation of the learning stop means H in the first aspect is set in accordance with the temperature state of the engine.

<Function> By adopting such a configuration, learning is stopped during startup and during a predetermined period of time after startup when engine friction is large and good learning of the feedback correction amount cannot be performed, and learning is stopped after the integral correction amount has stabilized. Since learning is started, fluctuations in the learning correction amount can be suppressed, and good learning can be continued.

<Example> Examples will be described below.

Figure 2 shows the hardware configuration.

11 is a CPU, 12 is a P-ROM, 13 is a CMOS-RAM for learning control, and 14 is an address decoder. Note that a backup power supply circuit is used for the RAM 13 in order to retain the stored contents even after the key switch is turned off.

Analog input signals to the CPU 11 for controlling the idle control valve 3 include a water temperature signal from the water temperature sensor 15, a throttle opening signal from the throttle sensor 16, and a battery voltage from the battery 17. The signal is input via an interface 18 and an A/D converter 19. 20 is an A/D conversion timing controller.

Digital input signals include ON/OFF signals from the starter switch 21, idle switch 22, neutral switch 23, and air conditioner switch 24.
There are OFF signals, which are input via the digital input interface 25.

In addition, for example, from the crank angle sensor 26
A reference signal every 180 degrees and a position signal every 1 degree are inputted via a one-shot multi-circuit 27. In addition, the vehicle speed sensor 27
The vehicle speed signal is inputted via the waveform shaping circuit 29.

Input signal from CPU11 (idle control valve 3
pulse signals) are sent to the valve-opening coil 3a and valve-closing coil 3b of the idle control valve 3 via the phase inversion driver 30 in a mutually inverted state.

Here, the CPU 11 executes the flowchart shown in FIG. 3 (routine for calculating the control value ISCdy of the duty ratio of the pulse signal to the idle control valve 3).
Input/output operations, arithmetic processing, etc. are performed according to a program (stored in the ROM 12) based on the ROM 12.

Next, the flowchart shown in FIG. 3 will be explained.

In S1, a basic control value ISCtw is set from the water temperature Tw detected by the water temperature sensor 15. This setting may be made by storing a map of the basic control value ISCtw with water temperature Tw as a parameter in advance in the ROM 12, and searching from the map, or by calculation. good.

Also, if necessary, change the transient correction amount ISCtr in S2 to S3.
Set the other correction amount ISCet with .

Furthermore, in S4, the learning correction amount ISCl is searched from the water temperature Tw. Note that a map of the learning correction amount ISCl with the water temperature Tw as a parameter is stored in the rewritable RAM 13, and all initial values are given at the time when learning has not started.

In S5, it is determined whether the ISC condition (area where ISC is performed) is met. Specifically, when the idle switch 22 that detects the fully closed state of the throttle valve is ON (the throttle valve is in the fully closed position) and the neutral switch 23 is ON (the gear position of the transmission is neutral), or when the idle switch 2
2 is ON and the vehicle speed detected by the vehicle speed sensor 28 is below a predetermined value, it is assumed that the ISC condition is satisfied, and the process proceeds to the next step S6.

In S6, the target rotation speed Ns is set by searching or calculating from the water temperature Tw.

In S7, target rotation speed Ns and crank angle sensor 26
The actual rotation speed N detected by is compared with the actual rotation speed N detected by . Then, the amount of feedback correction is determined by integral control.
Configure ISCfb. That is, if Ns>N, S8
Feedback correction amount based on integral control at
Increase ISCfb by a predetermined amount from the previous value, Ns<N
In this case, the feedback correction amount ISCfb is decreased by a predetermined amount from the previous value based on integral control in S9. When Ns=N (including the dead zone), the feedback correction amount ISCfb is kept at its previous value.

In S10, it is determined whether the starter switch 21 is in the starting (cranking) state depending on whether it is ON or not, and if this determination is NO,
Proceed to S11.

In S11, based on the water temperature Tw, a predetermined time after start-up at which learning is to be stopped is searched as described later.

In S12, it is determined whether the predetermined time set in S12 has passed after the determination in S10 becomes NO, that is, after startup, and when this determination becomes YES,
Proceed to S13.

In S13, the deviation amount ΔISCfb of the feedback correction amount ISCfb from the reference value (median value IC of integral control)
Based on (ISCfb-IC), the learning correction amount ISCle is updated as shown in the following equation.

ISCle←ISCle+ΔISCfb/M (M is a constant, M>1) The new learning correction amount ISCle is written to the corresponding water temperature in the RAM 13, and the data in the RAM 13 is updated. Next, proceed to S14.

On the other hand, at startup when S10 judgment is YES and S10
Until a predetermined period of time has elapsed after starting when the determination is NO, the process proceeds to S14 without updating the data of the learning correction amount ISCle in S13, that is, without performing learning.

In this way, learning starts when a predetermined period of time has elapsed after starting the engine.

In S14, the control device ISCdy is calculated using the following equation.

ISCdy=ISCtw+ISCtr+ISCet+ISCle+ISCfb If the ISC condition is not satisfied in S5, the process jumps to S14 without performing feedback control or learning, and calculates the control value ISCdy.

The control value ISCdy is calculated above, and this control value
A pulse signal with a duty ratio corresponding to ISCdy is transmitted to the idle control valve 3 via the phase inversion driver 30.
is applied to the valve opening coil 3a and the valve closing coil 3b.

In addition to the idle control valve of the type shown in FIG. 4, the present invention is applicable to control of various types of idle control valves that are opened and closed by pulse signals.

Further, in this embodiment, an embodiment of the second invention is shown in which a predetermined time after startup for stopping learning is set based on the water temperature Tw, but if this predetermined time is set constant, the first invention This is an example.

<Effects of the Invention> As explained above, according to the present invention, in the feedback control of the idle rotation speed, engine friction is large and the integral correction amount of the feedback correction amount obtained by integral control is large. Since learning of the feedback correction amount is stopped for a predetermined period of time and after startup, good learning control can be continuously performed, and the stability of idling rotation due to learning is increased to prevent engine stalling during transient operation.
The effect of truly promoting improvements in fuel efficiency, etc. can be obtained.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
The figure is a hardware configuration diagram showing an embodiment of the present invention, Figure 3 is a flowchart of the same as above, Figure 4 is a sectional view of a throttle chamber showing an example of an idle control valve, and Figure 5 is a conventional learning method. FIG. 3 is a diagram showing the characteristics of the feedback correction amount and engine speed immediately after starting by the control device. 1... Throttle valve, 2... Auxiliary air passage, 3
...Idle control valve, 11...CPU, 12...
P-POM, 13...CMOS-RAM, 15...
Water temperature sensor, 21... Starter switch, 22...
... Idle switch, 23 ... Neutral switch, 26 ... Crank angle sensor, 28 ... Vehicle speed sensor.

Claims (1)

[Claims] 1. In an internal combustion engine equipped with an idle control valve in an auxiliary air passage bypassing a throttle valve, the idle control valve is driven by a pulse signal and its opening degree is adjusted according to its duty ratio. a basic control value setting means for setting a basic control value for the duty ratio of the pulse signal; and a basic control value setting means for setting a basic control value for the duty ratio of the pulse signal, and a feedback correction amount being set by integral control by comparing the target rotation speed set based on the engine operating state and the actual rotation speed. A feedback correction amount setting means, a learning correction amount search means for searching a learning correction amount stored in the RAM according to the engine operating state, and adding a predetermined percentage of the deviation amount of the feedback correction amount from a reference value to the learning correction amount. A learning correction amount correction means for setting a new learning correction amount and updating data of the same engine operating state in RAM, a means for detecting the starting state of the engine, and a means for detecting the elapsed time after starting the engine. A means for measuring the elapsed time after starting, a learning stopping means for stopping the data update operation of the learning correction amount at the time of starting and a certain period of time after starting, and a pulse signal by adding the feedback correction amount and the learning correction amount to the basic control value. An internal combustion engine comprising: a control value calculation means for calculating a control value of a duty ratio; and a pulse signal output means for outputting a pulse signal of a duty ratio based on the calculated control value to an idle control valve. Learning control device for idle speed. 2. In an internal combustion engine equipped with an idle control valve in the auxiliary air passage that bypasses the throttle valve, the idle control valve is driven by a pulse signal and its opening degree is adjusted according to its duty ratio. basic control value setting means for setting a basic control value; and feedback correction amount setting means for setting a feedback correction amount by integral control by comparing a target rotation speed set based on the engine operating state and an actual rotation speed. a learning correction amount search means for searching the learning correction amount stored in the RAM according to the engine operating state; learning correction amount correction means for setting a learning correction amount and updating data of the same engine operating state in RAM; means for detecting the starting state of the engine; and means for measuring the elapsed time after starting the engine. a time measuring means; a learning stop means for stopping data update operation of the learning correction amount for a predetermined time set according to the temperature state of the engine at the time of starting and after starting; It is characterized by comprising a control value calculation means for calculating a control value of a duty ratio of a pulse signal by adding it, and a pulse signal output means for outputting a pulse signal of a duty ratio based on the calculated control value to an idle control valve. A learning control device for the idle speed of an internal combustion engine.