JP2532659Y2 - Idle speed control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to an idle speed control device for an internal combustion engine.

<Related Art> The following is a conventional example of an idle speed control device for an internal combustion engine.

That is, an electromagnetic idle control valve for an auxiliary air passage that bypasses the throttle valve is interposed, and a flow rate of the auxiliary air flowing through the auxiliary air passage is controlled by controlling a duty signal to the idle control valve. Specifically, the duty ratio to the idle control valve is feedback-controlled so that the idle rotation speed becomes the target rotation speed.

In addition, air conditioners (hereinafter abbreviated as air conditioners)
Alternatively, when an external load such as power steering is applied to the engine, the air conditioner electromagnetic coil is wound in parallel with the electromagnetic coil of the idle control valve so as to increase and compensate the auxiliary air flow rate. Japanese Patent Application Laid-Open No. Hei 1-292540 and Japanese Patent Application No. 1-2692982 have proposed a method in which the flow rate of auxiliary air is increased by energization.

<Problem to be Solved by the Invention> By the way, as shown in FIG. 5, when the duty ratio of only one of the electromagnetic coils is controlled when the air conditioner is turned off, the maximum when the idle control valve is closed and the auxiliary air flow becomes zero is obtained. When the air conditioner is turned on, the other electromagnetic coil is also energized, so that the valve opening force is large, so that the duty ratio can be varied by opening the valve even at a duty ratio smaller than the duty ratio a. Can control the valve opening amount.

However, conventionally, control was performed in the range of duty ratio a or more in accordance with turning on and off of the air conditioner, so that control in a small flow rate range could not be performed.

The present invention has been made in view of such circumstances.
It is an object of the present invention to provide an idle speed control device capable of optimally controlling the auxiliary air flow rate even when an external load is applied.

<Means for Solving the Problems> Accordingly, the present invention is as shown in FIG. 1, the electromagnetic external load that Hirakihen driving the valve body and the normal control solenoid coil A ₁ to be opened driving the valve body and the coil a ₂ is provided in parallel, set the idling control valve a for controlling the auxiliary air flow rate of auxiliary air passage bypassing the throttle valve, the control amounts to control the idle speed based on the engine operating condition the control amount setting means B, a first conductive member C to be supplied to the normal control solenoid coil a _1, the external load detecting means and D for detecting the presence or absence of the input of the external load, when the external load is turned second energizing means E for energizing the external load electromagnetic coil a ₂
And a minimum limit amount setting means G for setting a minimum control amount so as to be smaller when the external load is applied than when the external load is not applied, and a set minimum control amount and the set control amount. And an energization control means I for controlling the first energization means C based on the selected control amount or the minimum control amount.

<Operation> As described above, when the external load is applied and the electromagnetic coil for external load is energized, the energization control of the normal control electromagnetic coil is performed by setting the control amount to be smaller than when the external load is not applied. I did it.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2, an electromagnetic idle control valve 1 is interposed in an auxiliary air passage (not shown) that bypasses a throttle valve (not shown). As shown in FIG. 3, the idle control valve 1 has an electromagnetic coil for controlling the idling rotational speed.
1A and an air conditioner electromagnetic coil 1B are wound in parallel, and a duty signal is input to these electromagnetic coils 1A and 1B via transistors 2A and 2B, respectively.

The control device 3 including a microcomputer and the like includes a rotation speed detection signal from a rotation speed sensor 4, an on / off signal from an idle switch 5 that is turned on during idling, and a cooling water temperature detection signal from a water temperature sensor 6. And an on / off signal from the air conditioner switch 7 as an external load detecting means.

The control device 3 operates according to the flowchart of FIG. 4, and outputs a duty signal to the idle control valve 1 via a drive circuit 8 including the transistors 2A and 2B.

Here, the idle control valve 1 forms a control amount setting unit, a minimum control amount setting unit, a selection unit, and an energization control unit.
Further, the control device 3 and the drive circuit 8 constitute first and second energizing means.

Next, the operation will be described with reference to the flowchart of FIG.

First, the energization control when the air conditioner is turned on will be described. When the air conditioner switch 7 is turned on, the control device 3 outputs a duty signal to the air conditioner electromagnetic coil 1B of the idle control valve 1 via the drive circuit 8, By opening the valve quantitatively, the flow rate of the auxiliary air is increased to suppress a decrease in the idle speed.

During this control, the routine shown in the flowchart of FIG. 4 is executed.

That is, in S1, the basic control value ISCT _w is retrieved from the map based on the cooling water temperature detected by the water temperature sensor 6.

In S2, various correction amounts for air conditioner, D range, acceleration / deceleration, etc.
Set up ISCet.

In S3, it is determined whether or not the condition is the 1SC condition (the area where ISC is performed). If YES, the process proceeds to S4, and if NO, the process proceeds to S9.

In S4, the target rotation speed Ns is set based on the cooling water temperature.

In S5, the target rotation speed Ns is compared with the actual rotation speed N detected by the rotation speed sensor 4. Then, the feedback correction amount ISCfb is set by the integral control. That is, if Ns> N, the feedback correction amount ISCfb is increased by a predetermined amount from the previous value based on the integral control in S6, and N
If s <N, the feedback correction amount ISCfb is decreased by a predetermined amount from the previous value based on the integral control in S7. Ns
= N (including dead zone), feedback correction amount IS
Leave Cfb at the previous value.

In S8, the control value 1SCdy is obtained by adding the basic control value ISCTw, the various correction amounts ISCet, and the feedback correction amount ISCfb.

On the other hand, when the ISC condition is not satisfied, the control value ISCdy is obtained by adding the basic control value ISCTw and the various correction amounts ISCet in S9.

In S10, it is determined whether or not the air conditioner switch 7 is turned on. If YES, it is determined that the air conditioner electromagnetic coil 1B is energized, and the process proceeds to S11. If NO, the process proceeds to S12.

In S11, the minimum limit value LMTAC when the air conditioner is turned on is searched from the map.

In S12, the minimum limit value LMTN0M when the air conditioner is off is searched from the map. This minimum limit value LMTNOM is set to be larger than the minimum limit value LMTNOM when the air conditioner is turned on.

In S13, the control value ISC set in S8 or S9 is used.
dy is the minimum limit value LMTA searched in S11 or S12.
It is determined whether or not C is larger than LMTNOM, and if YES, S14
Proceeds to NO and S15 proceeds.

In S14, the control value ISCdy set in S8 or S9 is selected.

In S15, the minimum limit value L searched in S11 or S12
Select MTAC, LMTNOM.

Then, the selected control value ISCdy or the minimum limit value L
Duty signal corresponding to MTAC, LMTNOM
To control the auxiliary air flow rate.

By the way, when the air conditioner is on, the electromagnetic coil for the air conditioner
1B, a predetermined amount of auxiliary air is flowing through the idle control valve 1. Therefore, the duty ratio a (see FIG. 5) at which the auxiliary air flow rate is searched when the air conditioner is off is smaller than the duty ratio a (see FIG. 5). Even if the duty ratio is reduced, the auxiliary air flow rate can be controlled by the electromagnetic coil 1A without performing a search rate. Therefore, when the air conditioner is on, the auxiliary air flow rate can be optimally controlled to a smaller duty ratio than when the air conditioner is off, and controllability can be improved.

<Effects of the Invention> As described above, the present invention provides the minimum control amount of the normal control electromagnetic coil when the external load electromagnetic coil used when the external load is applied is arranged in parallel with the normal control electromagnetic coil. Is set to be smaller than when no external load is applied, so that the auxiliary air flow rate can be optimally controlled up to a small control amount range when the external load is applied.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG.
FIG. 5 is a flowchart for explaining the above, and FIG. 5 is a diagram for explaining the conventional disadvantages of the above. DESCRIPTION OF SYMBOLS 1 ... Idle control valve, 1A ... Electromagnetic coil 1B ... Electromagnetic coil for air conditioners, 3 ... Control device 5 ... Idle switch, 7 ... Air conditioner switch

Claims (1)

(57) [Scope of request for utility model registration] An electromagnetic coil for normal control for driving a valve element to open and an electromagnetic coil for external load for driving the valve element to open are provided in parallel, and auxiliary air in an auxiliary air passage bypassing a throttle valve. An idle control valve for controlling a flow rate, control amount setting means for setting a control amount for controlling an idle speed based on an engine operating state, first energizing means for energizing the electromagnetic coil for normal control, and an external load An external load detecting means for detecting whether or not the external load is applied, and a second energizing means for energizing the external load electromagnetic coil when an external load is applied. A minimum control amount setting means for setting a minimum control amount so as to be smaller when the load is not applied than when no load is applied; and comparing the set minimum control amount with the set control amount to select a larger one. Selection means for, idle speed control apparatus for an internal combustion engine, characterized by comprising, a power supply control means for controlling said first power supply means based on the control amount or minimum control amount is selected.