JP2795734B2 - Engine idle speed control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an engine in which, for example, an ISC valve is provided in a bypass passage that bypasses a throttle valve.

(Prior art) Conventionally, in order to suppress idle vibration during idling,
There is an engine control device configured to delay the ignition timing (see JP-A-60-17268).

According to this conventional device, there is an advantage that the rotation stability at the time of idling can be achieved, but on the other hand, there is a problem that fuel efficiency deteriorates because the ignition timing is retarded.

(Object of the Invention) The invention according to claim 1 of the present invention reduces the idling speed when the vehicle shifts from the running state to the idling state by decelerating, and corrects the ignition timing to the advanced side to reduce the idling time. It is an object of the present invention to provide an idle speed control device for an engine that can achieve both combustion stability and improved fuel efficiency.

In addition to the object of the first aspect of the present invention, the invention according to a second aspect of the present invention provides an idle speed reduction control and an ignition timing correction control only at the time of so-called sudden deceleration in which the transition to the idle state is performed rapidly. By doing so, it is an object of the present invention to provide an engine idle speed control device that does not cause a driver to feel idle vibration without feeling uncomfortable.

(Constitution of the Invention) The invention according to claim 1 of the present invention is an engine idle speed control device for feeding back an idle speed to a target speed by an ISC means based on intake air amount control, and decelerates from a running state. Idle transition detecting means for detecting that the state has shifted to the idle state, and idle speed reduction means for lowering the idle speed by a predetermined value via the ISC means only for a predetermined period after the transition to the idle state,
An idle speed control device for an engine, comprising a control means for controlling the drive of the idle speed reduction means and the ignition timing correction means based on the output of the idle shift detection means.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a transition speed detecting means for detecting a transition speed to the idle state is provided, and the transition speed detecting means is provided only during a rapid transition to the idle state. An engine idle speed control device for performing idle speed reduction control and ignition timing correction control.

(Effect of the Invention) According to the first aspect of the present invention, when the idle transition detecting means detects that the vehicle has decelerated from the running state and has transitioned to the idle state, the control means causes the idle rotation reducing means to operate. And drive control of the ignition timing correction means, so that the idle speed is reduced by the above-mentioned idle rotation reduction means only for a predetermined period after transition to idle, and the ignition timing is corrected to the advance side by the above-mentioned ignition timing correction means. I do.

In other words, immediately after the transition to the idle state, the engine temperature is high due to the running up to that point, and even if the idle speed is reduced, the degree of influence on the combustibility is relatively small. Thus, by improving the fuel efficiency and correcting the ignition timing to the advanced side, there is an effect that the combustion stability can be ensured, and both the above-described improvement in the fuel efficiency and the securing of the combustion stability can be achieved.

According to the second aspect of the present invention, in addition to the effects of the first aspect, the above-described respective controls are performed only when the above-mentioned transition speed detecting means detects a rapid transition to the idle state. Therefore, the above-mentioned controls are prohibited for slow deceleration, which has less downshoot and forcible lowering of idling speed causes a sense of incongruity. Since each control described above is performed only at the time, there is an effect that the driver does not experience idle vibration.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

The drawing shows an idle speed control device for an engine for a vehicle with an automatic transmission. In FIG. 1, an air flow sensor 2 is connected to the rear of an air cleaner 1 for purifying intake air. Is configured to be detected.

A throttle body 3 is connected to the rear of the above-mentioned air flow sensor 2, and a throttle valve 4 as a control valve for controlling an intake air amount is disposed in a throttle chamber 4 in the throttle body 3.

A surge tank 6 as an enlarged chamber having a predetermined volume is connected to an intake passage downstream of the throttle valve 5, and an intake manifold 8 communicating with an intake port 7 is connected downstream of the surge tank 6. The manifold 8 is provided with a fuel injection valve 9.

On the other hand, the above-described intake port 7 and exhaust port 12, which are appropriately communicated with the combustion chamber 11 of the vehicle engine 10 with an automatic transmission, have an intake valve that is opened and closed by a valve mechanism (not shown).
13 and exhaust valve 14 respectively, and the cylinder head
A spark plug 16 having a spark gap facing the above-described combustion chamber 11 is attached to 15.

An O ₂ sensor is provided in the exhaust passage 17 communicating with the exhaust port 12 described above.
At the rear of the exhaust passage 17, a catalytic converter 19 for rendering harmful gas harmless, a so-called catalyst, is connected.

By the way, an engine water temperature sensor 22 is attached to a water jacket 21 formed on the outer periphery of the intake manifold 8, and a bypass passage 23 for bypassing the throttle valve 5 is provided. The bypass passage 23 has an ISC (idle speed control). ) An ISC valve 24 is provided as a means.

FIG. 2 shows a control circuit of the idle speed control device,
The CPU 30 receives the intake air amount signal from the air flow sensor 2,
A water temperature signal from a water temperature sensor 22, an intake air temperature signal from an intake air temperature sensor 25, a shift position detection signal of an automatic transmission from an inhibitor switch 26, a throttle opening signal from a slot sensor 27, an idle signal from an idle switch 28, Based on a vehicle speed signal from a vehicle speed sensor 29 and an input of an engine speed signal from a distributor 31 or an ignition coil (not shown), an igniter coil 33, a spark plug 16, an ISC
The valve 24 and the timer 24 are driven and controlled.
Water temperature predetermined value data corresponding to 0 ° C., intake air predetermined value data corresponding to 20 ° C., idle target rotation decrease amount data, idle ignition timing data, idle ignition timing advance value data,
Necessary data such as ignition timing data corresponding to each operation state and data for determining quick transition to an idle state is stored.

Here, the CPU 30 is provided with idle transition detecting means for detecting that the vehicle has decelerated from the running state to the idle state, and after transition to the idle state, the ISC valve is set only by the timer 34 for a predetermined period. An idle speed lowering means for lowering the idle speed by a predetermined value via 24; an ignition timing correcting means for correcting the ignition timing to a predetermined amount advance side during the operation of the idle speed lowering means; and an idle shift detecting means. Control means for controlling the drive of the idle speed reduction means and the ignition timing correction means based on the output;
It also serves as a transition speed detecting means for detecting the transition speed to the idle state.

The operation of the idle speed control device for a vehicle engine with an automatic transmission having such a configuration will be described with reference to the flowcharts of FIGS.

First, the ISC process will be described with reference to the flowchart of FIG.

In a first step 41, the CRU 30 executes reading of various signals.

Next, in a second step 42, the CPU 30 compares the water temperature predetermined value data corresponding to 80 ° C. stored in the RAM 35 in advance with the current water temperature read in the first step 41, and determines whether the current water temperature is For example, during a warm-up operation at a temperature lower than 80 ° C., the process proceeds to an eighth step 48, whereas when the current water temperature is 80 ° C. or higher, the process proceeds to a third step 43.

In the third step 43, the CPU 30 compares the intake air temperature predetermined value data corresponding to 20 ° C. stored in the RAM 35 in advance with the current intake air temperature read in the first step 41, and determines whether the intake air temperature is higher. When the temperature is lower than 20 ° C., the process shifts to the above-described eighth step 48. On the other hand, when the intake air temperature is 20 ° C. or more, the next fourth step 44
Move to

That is, the above-described second step 42 and third step 43
It is determined whether or not the engine 10 is stable, and the routine proceeds to the above-described fourth step 44 only when the engine is stable.

In the fourth step 44, the CPU 30 sets the inhibit switch 2
It is determined from the signal from 6 whether or not it is in the droid range.
At the time of the range, the process proceeds to the next fifth step 45. On the other hand, when the shift range is other than the D range, the above-mentioned eighth step 48 is performed.
Move to

In the above-described fifth step 45, the CPU 30 determines whether or not the throttle is open or fully closed. When the throttle is fully closed, the CPU 30 proceeds to the next sixth step 46.

In the sixth step 46, the CPU 30 determines whether or not the transition speed at which the vehicle decelerates from the running state and shifts to the idle state is steep.

This determination is made based on whether or not the amount of change ΔV of the vehicle speed within the fixed time Δt is within a predetermined range V, that is, whether or not ΔV / Δt> V, to determine whether the transition is rapid or gradual. When the transition is gradual, the process proceeds to the above-described eighth step 48, whereas when the transition is abrupt, the process proceeds to the next seventh step 47.

In the seventh step 47, the CPU 30 determines whether or not the vehicle speed has reached O km / h.

That is, the seventh step 47 and the above-described fifth step 47
Then, the CPU 30 determines whether or not there is an idle state, and proceeds to the next ninth step 49 only during idle time.

In the ninth step 49, the CPU 30 sets the timer 34. The timer 34 is a timer for setting a predetermined period for lowering the idle speed by a predetermined value after the transition to the idle state, and a CPU built-in timer may be used.

In the above-described eighth step 48, the CPU 30 counts down the timer 34 when the total of the six determination conditions in the second to seventh steps 47 is not satisfied.

Next, in a tenth step 50, the CPU 30 determines whether or not the continuation time has elapsed when set by the timer 34, and proceeds to an eleventh step 51 when the time is up, and to a twelfth step 52 when the continuation is in progress. Respectively.

In the above-described eleventh step 51, the CPU 30 sets the idle target rotation speed to a normal target value that does not cause any reduction, while in the above-described twelfth step 52, the CPU 30 sets the idle target rotation speed to a value that reduces the idle target rotation speed by a predetermined value. .

Next, in a thirteenth step 53, the CPU 30 calculates a deviation between the idle target rotation speed and the current engine rotation speed, and executes a so-called rotation feedback control for controlling the ISC valve 24 so that the rotation speed deviation becomes zero when the calculation is performed. Run.

That is, when the idle shift detecting means (see the fifth step 45 and the seventh step) detects that the vehicle has decelerated from the running state and has shifted to the idle state, the CPU 30 described above reduces the idle rotation (see the twelfth step 52). After the transition to idle, the idle speed is reduced only for a predetermined period set by the timer 34 to improve fuel efficiency.

Next, referring to the flowchart of FIG.
The ignition timing control processing performed in parallel with the processing will be described.

In a first step 61, the CPU 30 executes reading of various signals.

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

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

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

That is, it is determined whether or not the above-described timer 34 is in operation and the idle speed reduction means (see step 12 in FIG. 3) is operating.
Move to 66.

In the sixth step 66, the CPU 30 sets the idle ignition timing IgI
By adding the correction amount ΔIg to D to set the ignition timing Ig, the ignition timing Ig is corrected to the advance side by a predetermined amount ΔIg.

Next, in a seventh step 67, the CPU 30 executes ignition for controlling the driving of the ignition plug 16 via the igniter coil 33 based on the above-mentioned ignition timing Ig.

In the above-described fourth step 64, the CPU 30 sets the engine 1
Set the ignition timing Ig corresponding to the operation state of 9.

In short, when the above-mentioned idle shift detecting means (see the fifth step 45 and the seventh step 47) detects that the vehicle has decelerated from the running state and has shifted to the idle state, the CPU 30 described above executes the idle rotation decreasing means (the twelfth step). 52) and the ignition timing correction means (refer to the sixth step 66).
After the shift to the idle state according to step 52), the idle speed is reduced only for a predetermined period, and the ignition timing is corrected to the advanced side by the above-described ignition timing correction means (see the sixth step).

As a result, at the time when the engine temperature is relatively high immediately after the transition to the idle state and the influence on the combustibility is small even when the idle speed is reduced, the idle speed is reduced to improve the fuel efficiency, Since the ignition timing is advanced-controlled to secure the combustion stability, there is an effect that it is possible to achieve both improvement of the fuel consumption and securing of the combustion stability.

In addition, such idle speed reduction control and ignition timing advance control are performed only when the above-mentioned transition speed detecting means (see the sixth step 46) detects a rapid transition to the idle state, so that a downshoot occurs. The above controls are prohibited during slow deceleration when there is a feeling of incongruity of forcibly lowering the idle speed. Therefore, there is an effect that the driver does not experience idle vibration.

In the correspondence between the configuration of the present invention and the above-described embodiment, the ISC means of the present invention corresponds to the ISC valve 24. Similarly, the idle transition detecting means performs the fifth step 45, the seventh step 47, the idle speed reduction means corresponds to the twelfth step 52 controlled by the CPU 30, and the ignition timing correction means controls the sixth step 6 controlled by the CPU 30.
6. The control means corresponds to the CPU 30, and the transition speed detecting means corresponds to the sixth step 4 based on the CPU 30 control.
6, the engine corresponds to the vehicle engine 10 with an automatic transmission. However, the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of the drawings]

1 shows an 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 ISC processing, FIG. It is a flowchart which shows an ignition timing control process. 10 Engine 24 ISC valve 30 CPU (control means) 45 5th step (idle transition detecting means) 46 ... 6th step (transition speed detecting means) 47 7th step (idle transition) Detecting means) 52: 12th step (idle rotation decreasing means) 66: 6th step (ignition timing correcting means)

Claims (2)

(57) [Claims] An idle speed control device for an engine for feeding back an idle speed to a target speed by ISC means based on intake air amount control, wherein the idle speed detecting device detects that the vehicle has decelerated from a running state and shifted to an idle state. Transition detecting means, idle speed lowering means for lowering the idle speed by a predetermined value via the ISC means only for a predetermined period after the transition to the idle state, and a predetermined amount of ignition timing during the operation of the idle speed lowering means. An engine idle speed control device comprising: an ignition timing correction means for correcting the ignition angle to an advanced angle side; and a control means for drivingly controlling the idle speed reduction means and the ignition timing correction means based on the output of the idle transition detection means. . 2. The engine according to claim 1, further comprising a transition speed detecting means for detecting a transition speed to the idle state, and performing the idle speed reduction control and the ignition timing correction control only during a rapid transition to the idle state. Idle speed control device.