JPH01200042A - Idle revolution speed controller for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an idle rotation speed control device for an internal combustion engine.
More specifically, the present invention relates to an idle rotation speed control device configured to feedback control an actual idle rotation speed to a target rotation speed by controlling the amount of auxiliary air supplied by bypassing a throttle valve.

<Prior Art> As disclosed in Japanese Patent Application Laid-Open No. 62-129544, an idling speed control device for an internal combustion engine uses an auxiliary air passage that bypasses a throttle valve installed in the intake system of the engine. There is one in which an idle control valve (ISC pulp) is provided in the middle, and the idle rotation speed is controlled by regulating the amount of auxiliary air using the idle control valve.

The idle control valve includes, for example, a valve opening coil and a valve closing coil, and a pulse signal (
The drive signals) are sent in an inverted state, and the opening degree is adjusted according to the duty ratio of the pulse signal.

The duty ratio of the pulse signal is determined, for example, by a control value l5Cdy calculated by the following equation. still,
The unit of this control value l5Cdy is expressed in %, and is output as a percentage of time that the valve opening coil is ON.

I S Cdy= I S Ctw+ I S Cet
+ I S Cfd Here, ISCtw is a basic control value dependent on engine cooling water temperature, l5Cet is various correction amounts such as acceleration/deceleration correction, and l5Cfd is a feedback correction amount for feedback control of idle rotation speed, which will be described later.

In idle rotation speed feedback control, the target idle rotation speed, which depends on the engine temperature represented by the cooling water temperature, is compared with the actual rotation speed detected by the rotation angle signal from the crank angle sensor, etc., and the difference is calculated. If there is a problem, the control value at that time is corrected to control the target rotation speed, and for this reason, the feedback correction 111scfd described above is defined.

The feedback correction amount l5CfdO value is changed by integral control or proportional-integral control to achieve stable control. That is, 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 l5Cfd is increased (decreased) by a minute amount (integral constant). I'll let you do it.

However, the feedback control of the idle rotation speed using the feedback correction amount l5Ofd is performed when predetermined conditions are met, that is, in a predetermined idling operating state. This predetermined condition is when the throttle valve is in a fully closed position (idle position) and the transmission is in a neutral state, or when the throttle valve is in a fully closed position and the vehicle speed is below a predetermined speed (for example, 8 km/h).

However, if feedback control is started immediately from a high speed state, such as after acceleration with the transmission in the neutral state, there will be a large difference between the target idle speed and the actual value, so the opening of the idle control valve is controlled to the fully closed side, and as a result, when the rotation speed returns to around the target idle rotation speed, the control response delay causes a large rotation drop. Feedback control is started after a predetermined delay time after all are completed.

(Problem to be Solved by the Invention) The time for delaying the feedback control as described above is, for example, the time from a high rotation of around 6000 rpm+ to a return to around idling rotation when the transmission is in a neutral state (for example, 4 seconds). This is to ensure that even after high-speed dry cooking, feedback control is started after the rotation has sufficiently decreased to prevent a dramatic drop in rotation speed. However, if the time to return to idle rotation after dry cooking is shorter than the delay time of the feedback control, that is, if dry cooking is performed with a peak rotation at a low rotation of about 200 rpm, the feedback control starts with a delay. Until this feedback control is started, as shown in Fig. 4, the target is determined by the basic control value ISCtw (idle sustained demand amount + engine stall prevention flow rate) etc., which depends on the cooling water temperature. A control value l5Cdy that is larger than the idle rotation speed request is sometimes set, resulting in a failure to return the idle rotation speed.

The present invention has been made in view of the above problems, and while avoiding a large drop in idle rotation speed after idling,
It is an object of the present invention to provide an idle rotation speed control device that can prevent the occurrence of a failure in returning to the idle rotation speed after idling.

<Means for solving the problem> Therefore, in the present invention, as shown in FIG.
The idle speed control device for an internal combustion engine is configured to include means G.

(A) An idle control valve that is installed in an auxiliary air passage that bypasses a throttle valve installed in the intake system of the internal combustion engine and controls the flow rate of auxiliary air that is supplied to the engine via the auxiliary air passage. (B) Engine rotation speed An engine rotation speed detection means (C) for detecting the engine rotation speed detected by the engine rotation speed detection means to a target rotation speed by controlling the auxiliary air flow rate according to the opening degree of the idle control valve in a predetermined idle operating state. Idle rotation speed control means for performing feedback control (D) Idle operation state detection means for detecting a predetermined idle operation state that performs feedback control of the idle rotation speed by the idle rotation speed control means (E) Detected by the idle operation state detection means CF) Maximum rotational speed detection means for detecting the maximum rotational speed when the throttle valve is fully closed and the transmission is in the neutral state a immediately before the predetermined idle operating state. Feedback delay period setting means (G) for setting the start delay period of feedback control by the idle rotation speed control means based on the maximum rotation speed detected by the maximum rotation speed detection means when detected; (G) the idle operation state detection; Feedback control activation means for activating the idle rotation speed control means after the start delay period set by the feedback delay period setting means from the first time the predetermined idle operation state is detected by the means. In this configuration, the idle operation state detection means Feedback control of the idle rotation speed by the idle rotation speed control means C is not immediately started even when the idle rotation speed control means C detects a predetermined idle operation state; The maximum rotational speed when the throttle valve is fully closed and the transmission is in the neutral state before detection is detected by the maximum rotational speed detection means E, and the feedback delay period setting means F is set to the predetermined idle according to this maximum rotational speed. Set the delay time until starting feedback control when the operating state is detected.

Then, after the start delay period has elapsed since the initial detection of a predetermined idle operating state by the idle operating state detection means, the idle rotation speed control means is activated by the feedback control activation means G, and the actual speed detected by the engine rotation speed control means B is Feedback control of the opening degree of the idle control valve is started to control the engine rotation speed to the target rotation speed.

That is, the start delay time of feedback control of the idle rotation speed is not set constant, but the delay time is set variably according to the maximum rotation speed when the throttle valve is fully closed and in a neutral state immediately before feedback control of the idle rotation speed is performed. This makes it possible to start feedback control without response delay while avoiding feedback control from high engine speeds.

<Example> An embodiment of the present invention will be described below based on the drawings.

Figure 2 shows a schematic configuration of the hardware.

An idle control valve 5 is installed in the middle of an auxiliary air passage 4 that bypasses a throttle valve 3 installed in an intake passage 2 of an internal combustion engine 1.
This is provided.

The idle control valve 5 includes a valve opening coil and a valve closing coil, and its opening degree is controlled according to the duty ratio of a pulse signal sent from the control unit 6 via the drive circuit 7. There is.

The control unit 6 includes a signal for each predetermined crank angle from a crank angle sensor 8 as an engine rotation speed detection means, a vehicle speed signal from a vehicle speed sensor 9, and an idle switch 10 that is turned ON when the throttle valve 3 is in the fully closed position. ．． Neutral switch 11° ON/OFF signals from starter switch 12, cooling water temperature signal from water temperature sensor 13, throttle valve opening signal from throttle sensor 14, etc. are input.

Further, the output signals from the control unit 6 (driving pulse signals to the idle control valve 5) are inverted by a drive circuit 7 constituted by a phase inverting driver, etc., and then sent to the opening coil of the idle control valve 5. and a valve-closing coil.

Here, the control unit 6 is configured to perform input/output operations, arithmetic processing, etc. according to a program based on the flowchart shown in FIG. Rotation speed control means, feedback control activation means.

It also serves as feedback delay period setting means.

The routine shown in the flowchart of FIG. 3 is a routine for calculating the control value ISCdy that determines the duty ratio of the pulse signal to the idle control valve 5, and is executed every predetermined time (for example, 10 m5).

In step 21, it is determined whether the coolant temperature Tw detected by the water temperature sensor 13 is high or low relative to a predetermined temperature, and if it is lower than the predetermined temperature, the process proceeds to step 28, where a timer is used to measure the idle rotation speed feedback start delay time FBDLY. Reset the value TMFBDLY to zero.

On the other hand, when it is determined in step 21 that the cooling water temperature Tw is equal to or higher than the predetermined temperature and the engine 1 is in a substantially warm state,
In the next step 22, the neutral switch 11 is set to 0N-.
When it is determined that the transmission is OFF and the neutral switch 11 is ON and the transmission is in the neutral state,
Proceed to the next step 23.

In step 23, the idle switch 10 is turned ON/OFF.
F is determined, and if the idle switch 10 is ON, the process proceeds to step 24 to start feedback control of the idle rotation speed.

That is, feedback control of the idle rotational speed is performed only during idle operation when the cooling water temperature Tw is above a predetermined temperature and the transmission is in the neutral state, and feedback control is not performed when each of the above three conditions is not satisfied. Proceeding to step 28, the timer value TMFBDLY is reset to zero. Therefore,
In this embodiment, the idle operation state detection means is the water temperature sensor 13. Neutral switch 11. This corresponds to the idle switch 10.

When the conditions for performing feedback control of the idle rotation speed are met and the process proceeds to step 24, it is determined whether or not the conditions are met for the first time. If it is the first time, the timer value TMFBDLY is reset to zero in step 25 and the maximum value at this time is The peak N which is the rotational speed is detected, and if it is not the first time, the process proceeds to step 26 and the timer value TMFB is detected.
Increase DLY by 1. Therefore, the timer value TMFBDLY is incremented by 1 every time this routine is executed after the conditions for feedback control of the idle rotation speed are met.

Then, in the next step 27, based on the map of target rotational speeds N and T that are set corresponding to the cooling water temperature Tw, the rotation speed is determined according to the current operating state based on the cooling water temperature Tw detected by the water temperature sensor 13. The target rotation speed N stt is searched, and in the next step 28, this target rotation speed N0a is subtracted from the peak N obtained in step 25 (the maximum rotation speed when the throttle valve is fully closed and the neutral state is reached). Then, the rotational speed difference Δpeak N from the peak rotational speed to the target rotational speeds N8 and N7 at the first time when the conditions for performing feedback control of the idle rotational speed are satisfied is determined. still,
The target rotational speed N,1 is set higher as the cooling water temperature Tw is lower, thereby improving idling stability when the engine is cold.

In step 29, a delay time FBDLY is set in advance in correspondence with the Δ peak N, and a delay time FBDLY is determined based on the calculation result in step 28.
Search for BDLY.

The delay time FBDLY is set to a larger value as the Δbeak N (maximum rotational speed when the throttle valve is fully closed and in the neutral state) is larger. When the rotation speed reaches high rotation speed, a long delay time FBDLY is set to avoid starting feedback control when the rotation speed N is high and there is a large difference from the target rotation speed. By setting the delay time FBDLY to be shorter than when the engine is running at high speed, it is possible to avoid a failure in returning to the target rotational speed due to a delay in starting feedback control.

After setting the delay time FBDLY in step 29, in the next step 30, the delay time FBDLY and the timer value T are set.
The delay time FBD after the conditions for performing feedback control of the idle rotation speed are established by comparing with MFBDLY.
Determine whether LY has elapsed.

Here, when it is determined that TMFBDLY>FBDLY and the delay time FBDLY has elapsed, step 3
Feedback correction amount l5C in steps 1 to 34
fb (expressed as the percentage of time that the valve opening coil of the idle control valve 5 is ON) is set, and TMFB
It is determined that DLY≦FBDLY and the delay time FBD
If LY has not elapsed, the setting of the feedback correction amount l5Cfb in steps 31 to 34 is skipped and the process proceeds to step 35.

Setting of the feedback correction amount l5Cfb is performed as follows. First, in step 31, step 27
Target rotational speed N, found by searching for ! , by subtracting the actual rotational speed N from, the target rotational speed NS! ? Calculate the deviation ΔN of the actual rotational speed N from the actual rotational speed N.

Then, in step 32, the deviation ΔN is on the positive side and the actual rotational speed N is the target rotational speed N,! If it is below A, the correction amount l5CI (I
The absolute value of SCfb - previous l5Cfb + l5CI + l5CP) is set to increase on the plus side, and conversely, when the deviation ΔN is on the minus side, the actual rotational speed N is the target rotational speed Ns! ,
If it exceeds, feedback correction 111scfb
In order to decrease the error, the absolute value of the correction amount l5CI is set to increase on the negative side substantially in accordance with the increase in the absolute value of ΔN.

That is, the actual rotational speed N is equal to the target rotational speed N3. .

When the difference is larger, the feedback correction amount l5Cfb is more negatively corrected to reduce the opening degree of the idle control valve 5, and conversely, the actual rotation speed N is lower than the target rotation speed N5ET. Sometimes, the larger the difference, the more positive feedback correction tlscfb is made to open the idle control valve 5 more.

At step 33, a correction amount ISCP is also set according to the ΔN according to the following equation.

l5CP←ΔN/Nt
is set to a small value that is almost negligible, so that hunting in the rotational speed N due to the feedback correction amount l5Cfb does not occur.

Then, in the next step 34, the feedback correction amount l5Cfb is calculated according to the following equation.

l5Cfb←Previous l5Cfb+l5CI+l5CP Once the feedback correction amount l5Cfb is set in this way, in the next step 35, a basic value ISCtw based on the cooling water temperature Tw is set. This basic value l5Ct- is set to be larger as the cooling water temperature Tw is lower, so as to ensure engine stability at the time of starting.

In step 36, a starting diameter correction amount l5CA is set based on the cooling water temperature Tw. This starting diameter correction amount l5Oas
is set for a predetermined period immediately after starting (after turning the starter switch 12 from ON to OFF), thereby increasing the idle rotation speed and smoothing the transition from cranking.

In step 37, a dashpot correction amount 15Coso for preventing the intake manifold negative pressure from reaching about 1620 amHg during deceleration is set in accordance with the engine rotational speed N.

Then, in the next step 38, a control value 5cay that determines the duty ratio of the pulse signal (drive signal) sent to the valve-opening coil and valve-closing coil of the idle control valve 5, respectively, is calculated according to the following equation.

I5Cdy-ISCfb+ISCtw+I5Ca
s+ I S CD3N In the next step 39, the control value l5Cdy calculated in step 38 is output to the drive circuit 7, and the drive circuit 7 outputs the pulse signals of the duty ratio determined by the control value l5Cdy to the idle state in a mutually inverted state. The control value l5 is output to the valve opening coil and valve closing coil of the control valve 5.
The idle control valve 5 is controlled to an opening degree according to Cdy.

Note that the peak N detected in step 25 and the peak N detected in step 27
The delay time FBDLY may be controlled according to the difference between the rotational speed N5ET and the target rotational speed N5ET determined by the water temperature Tw.

In this case, control accuracy is further improved.

<Effects of the Invention> As explained above, according to the present invention, the idle rotation speed is adjusted according to the maximum rotation speed when the throttle valve is fully closed and in the neutral state immediately before the idle operation state in which feedback control is performed is detected. Since the delay time until the start of feedback control is set, feedback control will not be performed when the feedback control starts too quickly and the deviation from the target rotation speed is too large, and the feedback control will not start. This has the effect of preventing a failure in returning to the idle rotation speed due to a delay.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, Fig. 3 is a flowchart showing control details of the above embodiment, and Fig. 4 is a conventional problem. It is a time chart for explaining the points. 1... Engine 3... Throttle valve 4... Auxiliary air passage 5... Idle control valve 6... Control unit 8... Crank angle sensor 10
... Idle switch 11 ... Neutral switch 13 ... Water temperature sensor Patent applicant Japan Electronics Co., Ltd. Representative Patent attorney Fujio Sasashima Figure 1

Claims (1)

[Scope of Claims] An idle control valve that is provided in an auxiliary air passage that bypasses a throttle valve installed in an intake system of an internal combustion engine and controls the flow rate of auxiliary air that is supplied to the engine via the auxiliary air passage; an engine rotation speed detection means for detecting a rotation speed; and a rotation speed detected by the engine rotation speed detection means by controlling an auxiliary air flow rate according to the opening degree of the idle control valve in a predetermined idle operating state as a target rotation speed. an idle rotation speed control means for performing feedback control on the idle rotation speed; an idle operation state detection means for detecting a predetermined idle operation state in which the idle rotation speed is feedback-controlled by the idle rotation speed control means; a maximum rotational speed detecting means for detecting the maximum rotational speed when the throttle valve is fully closed and the transmission is in a neutral state immediately before a predetermined idle operating state; and a predetermined idle operating state is detected by the idle operating state detecting means. feedback delay period setting means for setting a start delay period for feedback control by the idle rotation speed control means based on the maximum rotation speed detected by the maximum rotation speed detection means when an internal combustion engine comprising: feedback control starting means for starting the idle rotation speed control means after a start delay period set by the feedback delay period setting means from the first time the idle operating state of the engine is detected; Idle rotation speed control device.