JPH0460145A - Idle speed control device of engine - Google Patents

Abstract

PURPOSE:To contrive compatibility of fuel stability and fuel consumption improvement at idle time by correcting ignition timing to an advance timing side while decreasing an idle speed at the time of a transfer with a speed decreased from a running condition to an idle condition. CONSTITUTION:A control circuit of an idle speed control device has a CUP 30 to which an engine speed signal from a distributor 31 is input in addition to output signals of an air flow sensor 2, water temperature sensor 22, intake air temperature sensor 25, inhibiter switch 26, throttle sensor 27, idle switch 28 and a car speed sensor 29. An ignitor coil 33, spark plug 16 and an ISC valve 24 are drive-controlled in accordance with a program stored in a ROM 32. When a transfer by reducing a speed from a running condition to an idle condition is detected, ignition timing is corrected to a predetermined advance timing side simultaneously with decreasing an idle speed by a predetermined value through the ISC valve 24 only for a predetermined period set by a timer 34.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine idle speed control device in which, for example, an ISC valve is interposed in a bypass passage that bypasses a throttle valve.

(Prior Art) Conventionally, there is an engine control device (see Japanese Unexamined Patent Publication No. 117268) that is configured to delay ignition timing for the purpose of suppressing idling vibration during idling.

This conventional device has the advantage of improving rotational stability during idling, but has the problem of poor fuel efficiency because it retards the ignition timing.

(Object of the Invention) The invention according to claim 1 of the present invention reduces the idle rotation speed when decelerating from a running state and shifts to an idling state, and also corrects the ignition timing to the advance side.
The purpose of the present invention is to provide an engine idle speed control device that can achieve both combustion stability and improved fuel efficiency during idling.

The invention set forth in claim 2 of the present invention, in addition to the object of the invention set forth in claim 11, provides idle speed reduction control and ignition timing correction only during so-called sudden deceleration when the transition to the above-mentioned idle state occurs rapidly. An object of the present invention is to provide an engine idle rotation speed control device that does not give a sense of discomfort and does not cause a driver to experience idle vibration by performing the control.

(Structure of the Invention) The invention according to claim 1 of the present invention is an engine idle speed control device that feeds back the idle speed to a target speed using 186 means based on intake air amount control. an idle transition detection means for detecting that the vehicle has entered the idle state; and an idle rotation reduction means for reducing the idle revolution speed by a predetermined value via the ISC means for a predetermined period only after the transition to the idle state;
The engine idle speed control device is characterized in that it includes a control means for driving and controlling the idle speed reduction means and the ignition timing correction means based on the output of the idle transition detection means.

The invention set forth in claim 2 of the present invention provides, in addition to the configuration of the invention set forth in claim 1, transition speed detection means for detecting the speed of transition to the idle state, and only when the rapid transition to the idle state occurs. The present invention is characterized by an engine idle speed control device that performs idle speed reduction control and ignition timing correction control.

(Effects of the Invention) According to the invention as set forth in claim 1 of the present invention, when the above-mentioned idle transition detection means detects that the driving state has decelerated and shifted to the idle state, the above-mentioned control means controls the idle speed reduction means. Since the ignition timing correction means is drive-controlled, the idle rotation speed is reduced only for a predetermined period after the transition to idle by the above-mentioned idle rotation reduction means, and the ignition timing is corrected to the advanced side by the above-mentioned ignition timing correction means. do.

In other words, immediately after the transition to the idle state, the engine temperature is high due to previous driving, and reducing the idle speed has relatively little effect on combustibility, so the idle speed is reduced immediately after the transition to the idle state. Therefore, by aiming to improve fuel efficiency and correcting the ignition timing to the advanced side, combustion stability is ensured, and there is an effect that it is possible to achieve both the above-mentioned improvement in fuel efficiency and ensuring combustion stability.

According to the invention recited in claim 2 of this invention, the above claim 1
In addition to the effects of the invention described above, since each of the above-mentioned controls is performed only when the above-mentioned transition speed detection means detects a rapid transition to the idle state, there is little downshoot, and there is no discomfort when the idle speed is forcibly lowered. Each of the above-mentioned controls is prohibited during certain slow decelerations, and the above-mentioned controls are performed only during sudden decelerations when there is undershoot and no discomfort is felt even if the idle speed is lowered, so the driver can experience no idle vibration. There is no effect.

(Example) An embodiment of the present invention will be described in detail below based on the drawings.

The drawing shows an idle speed control device for an engine for a vehicle with an automatic transmission, and in FIG. 1, an air flow sensor 2 is connected to the rear of an air cleaner 1 that purifies intake air.
This air flow sensor 2 is configured to detect the amount of intake air.

A throttle body 3 is connected to the rear of the air flow sensor 2 described above, and a throttle chamber 4 within the throttle body 3 is provided with a throttle valve 5 as a control valve for controlling the amount of intake air.

A surge tank 6 serving as an expansion chamber having a predetermined volume is connected to the intake passage downstream of the throttle valve 5.
An intake manifold 8 that communicates with the intake photo 7 is connected downstream of the surge tank 6, and a fuel injection valve 9 is disposed in the intake manifold 8.

On the other hand, the above-mentioned intake boat 7 and exhaust boat 12, which communicate with the combustion chamber 11 of the engine 10 for a vehicle with an automatic transmission, as appropriate.
An intake valve 13 and an exhaust valve 14 which are opened and closed by a valve mechanism (not shown) are respectively attached to the cylinder head 15, and an ignition plug 16 with a spark gap facing the combustion chamber 11 is attached to the cylinder head 15. It is installed.

An 02 sensor 18 is disposed in the exhaust passage 17 that communicates with the exhaust boat 12, and a so-called catalyst is connected downstream of the exhaust passage 17 to render harmful gases harmless.

By the way, an engine water temperature sensor 22 is attached to the water jacket 21 formed on the outer periphery of the above-mentioned intake manifold 8, and a bypass passage 23 that bypasses the above-mentioned throttle valve 5 is provided.
An ISC valve 24 is provided as an idle speed control means.

Figure 2 shows the control circuit of the idle speed control device, and shows the control circuit of the idle speed control device.
PU30 is the intake air amount signal from the air flow sensor 2;
A water temperature signal from the water temperature sensor 22, an intake air temperature signal from the intake air temperature sensor 25, an automatic transmission shift position detection signal from the inhibitor switch 26, a throttle opening signal from the throttle sensor 27, an idle signal from the idle switch 28, Based on each input of the vehicle speed signal from the vehicle speed sensor 29 and the engine speed signal from the distributor 31 or ignition coil (not shown), the ROM 3
According to the program 2 stored in 2, the igniter coil 3
3. Drive and control the spark plug 16, ISC valve 24, and timer 34, and set R and A M 35 to 80°C, for example.
water temperature predetermined value data corresponding to 20°C, intake temperature predetermined value data corresponding to 20°C, idle target rotation reduction amount data, idle ignition timing data, idle ignition timing advance value data, ignition timing data corresponding to each operating state, idle Stores necessary data such as rapid transition determination data.

Here, the above-mentioned CPU 30 includes an idle transition detection means that detects deceleration from the running state to the idle state, and the ISC valve 24 for only a predetermined period set by the timer 34 after the transition to the idle state. an idle speed reduction means for reducing the idle speed by a predetermined value via the idle speed reduction means; an ignition timing correction means for correcting the ignition timing to advance by a predetermined amount while the idle speed reduction means is in operation; and an output of the idle shift detection means. It also serves as a control means for driving and controlling the idle speed reduction means and the ignition timing correction means based on the above, and a transition speed detection means for detecting the speed of transition to the idle state.

The operation of the idle speed control device for an engine for a vehicle with an automatic transmission configured as described above will be explained with reference to the flowcharts shown in FIGS. 3 and 4.

First, the IsC processing will be described with reference to the flowchart in FIG.

In a first step 41, the CPL 130 reads various signals.

Next, in a second step 42, the CPU 30 stores water temperature predetermined value data corresponding to 80° C. stored in the RAM 35 in advance, and
The current water temperature read in the first step 41 is compared with the current water temperature, and when the current water temperature is less than 80°C, for example during warm-up operation, the process moves to the eighth step 48, while when the current water temperature is 80°C or higher, the next step is performed. The process moves to the third step 43.

In this third step 43, the CPU 30 stores the intake temperature predetermined value data corresponding to 20° C. stored in the RAM 35 in advance, and
When the intake temperature is cold (less than 20 degrees Celsius), the process moves to the eighth step 48, while when the intake temperature is 20 degrees Celsius or higher, The process moves to the next fourth step 44.

That is, the above-mentioned second step 42 and third step 4
In Step 3, it is determined whether the engine 10 is stable or not, and the process moves to the fourth step 44 described above only when the engine is stable.

In this fourth step 44, the CPU 30 determines whether or not it is in the tribe range based on the signal from the inhibitor switch 26, and when it is in the D range, it moves to the next fifth step 45, while in the case of a shift range other than the D range, as described above. The process moves to the eighth step 48.

At the fifth step 45 described above, the CPU 30 determines whether the throttle opening is fully closed or not, and when the throttle opening is fully closed, the process proceeds to the next sixth step 46.

In the sixth step 46, the CPU 30 determines whether the speed at which the vehicle decelerates from the running state to the idle state is rapid.

This determination is based on whether or not the amount of change Δ■ in vehicle speed within a certain time Δ is within a predetermined range V, that is, ΔV/
It is determined whether the transition is rapid or gradual depending on whether Δt>V, and when the transition is gradual, the process moves to the above-mentioned eighth step 48, while when the transition is sudden, the process moves to the next seventh step 47.

In this seventh step 47, the CPU 30 determines whether the vehicle speed is Okm/
It is determined whether or not h has been reached.

In other words, this seventh step 47 and the fifth step 4 described above
5, the CPU 30 determines whether or not there is an idle state, and moves to the next ninth step 49 only in the idle state.

In this ninth step 49, the CPU 30 sets the timer 34. After transitioning to the idle state, this timer 34
A CPU built-in timer may be used as a timer that sets a predetermined period for reducing the idle rotation speed by a predetermined value.

Note that in the eighth step 48 described above, the CPU 30
The above-mentioned timer 34 is counted down when a total of six judgment conditions are not met in steps 42 to 7th step 47.

Next, in a tenth step 50, the CPU 30 starts the timer 34.
Determine whether the set elapsed time has elapsed,
When the time is up, the process moves to the 11th step 51, and when the time is in progress, the process moves to the 12th step 52.

In the above-mentioned eleventh step 51, the CPU 30 sets the idle target rotation speed to a normal target value that does not reduce the idle target rotation speed by the same amount, while in the above-mentioned twelfth step 52, the CPU 30 sets the idle target rotation speed to a value that lowers the idle target rotation speed by a predetermined value. Set.

Next, in a thirteenth step 53, the CPU 30 calculates the deviation between the idle target rotation speed and the current engine rotation speed, and adjusts the ISC valve 24 so that the calculated rotation speed deviation becomes zero.
So-called rotation feedback control is executed to control the rotation.

That is, when the idle transition detection means (see the fifth step 45 and the seventh step) detects that the vehicle has decelerated from the running state and has transitioned to the idle state, the CPU 30 described above
controls the idle rotation reduction means (see twelfth step 52), and after transition to idle, the above-mentioned timer 34 is activated.
The idle speed is reduced only for a predetermined period set in
Aim to improve fuel efficiency.

Next, with reference to the flowchart in FIG. 4, the above-mentioned ISC
The ignition timing control processing, which is processed in parallel with the above processing, will be described.

In a first step 61, the CPU 30 reads various signals.

Next, in a second step 62, the CPU 30 determines whether or not it is idle, and when it is idle, it moves to the next third step 63, while when it is not idle, it moves to another fourth step 64.

In the third step 63 described above, the CPU 30 sets the ignition timing IglD corresponding to the idle state.

Next, in a fifth step 65, the CPU 30 determines whether or not the idle target rotation is decreasing.

That is, it is determined whether the above-mentioned timer 34 is running and the idle speed reduction means (see step 12 in FIG. 3) is in operation, and when the target idle speed is being reduced, the next step 66 is executed. to move to.

In this sixth step 66, the CPU 30 sets the ignition timing rg by adding the correction amount ΔIg to the idle ignition timing 1gID, thereby correcting the ignition timing 1g to the advance side by a predetermined amount ΔIg.

Next, in a seventh step 67, the CPU 30 executes ignition to drive and control the spark plug 16 via the igniter coil 33 based on the above-mentioned ignition timing 1g.

Note that in the fourth step 64 described above, the CPU 30 sets the ignition timing Ig corresponding to the operating state of the engine 10.

In short, when the above-mentioned idle transition detection means (see the fifth step 45 and the seventh step 47) detects that the vehicle has decelerated from the running state and shifted to the idle state, the above-mentioned CPU 30 detects the idle speed reduction means (see the twelfth step). 52) and ignition timing correction means (sixth step 6)
6)), the above-mentioned idle speed reduction means (see 12th step 52) reduces the idle speed only for a predetermined period after the transition to idle, and the above-mentioned ignition timing correction means (see 6th step 52) reduces the idle speed. (see) to correct the ignition timing to the advanced side.

As a result, the engine temperature is relatively high immediately after the transition to the idle state, and lowering the idle speed will have little effect on combustibility.At the same time, lowering the idle speed will improve fuel efficiency. Since combustion stability is ensured by advanced control of the ignition timing, it is possible to improve fuel efficiency and ensure combustion stability at the same time.

In addition, such idle speed reduction control and ignition timing advance control are performed by the above-mentioned transition speed detection means (sixth
(see step 46) or when a rapid transition to the idle state is detected. Therefore, the above-mentioned controls are inhibited during slow deceleration when there is little downshoot and it would feel strange to forcefully lower the idle speed. Since the above-mentioned controls are performed only during sudden deceleration when there is no discomfort even if the idle speed is lowered, there is an effect that the Drino does not experience idle vibration.

In the correspondence between the configuration of the present invention and the above-described embodiments, the ISC means of the present invention corresponds to the ISC valve 24, and similarly, the idle transition detection means corresponds to the fifth step 45 and the seventh step controlled by the CPU 30. 47, the idle speed lowering means is the twelfth step 5 controlled by CPtJ30.
2, the ignition timing correction means corresponds to the sixth step 66 controlled by the CPU 30, the control means corresponds to the CPU 30, the transition speed detection means corresponds to the sixth step 46 controlled by the CPU 30, and the engine Although the present invention corresponds to an engine 10 for a vehicle with an automatic transmission, the present invention is not limited to the configuration of the above-described embodiment.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, Fig. 1 is a system diagram showing an engine idle speed control device, Fig. 2 is a control circuit block diagram, Fig. 3 is a flowchart showing SC processing, and Fig. 4 is a flowchart showing ignition timing control processing. 10... Engine 24... ISC valve 30... CPU (control means) 45... Fifth step (idle transition detection means) 46.
...6th step (transition speed detection means) 47...7th step
Step (idle shift detection means) 52...12th step (idle rotation reduction means) 66...6th step (ignition timing correction means) Fig. 2 gripping hand Q)

Claims (2)

[Claims] (1) An engine idle speed control device that feeds back the idle speed to a target speed using ISC means based on intake air amount control, and has an idle transition detection system that detects deceleration from a running state to an idle state. means for reducing the idle speed by a predetermined value via the ISC means for a predetermined period only after the transition to the idle state; and advancing the ignition timing by a predetermined amount while the idle speed reducing means is in operation. An engine idle speed control device comprising: ignition timing correction means for correcting the ignition timing to the side; and control means for driving and controlling the idle speed reduction means and the ignition timing correction means based on the output of the idle transition detection means. (2) The idle speed of the engine according to claim 1, further comprising transition speed detection means for detecting the speed of transition to the idle state, and performing the idle speed reduction control and the ignition timing correction control only when rapidly transitioning to the idle state. Number control device.