JPH0631159Y2 - Idle speed control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for controlling an idle speed of an internal combustion engine, and more particularly to a device for suppressing engine vibration.

<Prior Art> Conventionally, there is an internal combustion engine mounted on a vehicle that variably controls the rotational speed during idling according to operating conditions. Specifically, an idle control valve is installed in the auxiliary air passage formed by bypassing the intake throttle valve, and when the electrical load is large, the valve opening is increased to increase the auxiliary air amount and idle speed. Is controlled to increase the (Actual development 60-1
88840, etc.).

<Problems to be solved by the invention> In an engine not equipped with the above idle speed control device, when the consumed electric load is large, the engine speed decreases, the rotation becomes unstable, and the engine vibration increases. This caused problems such as steering wheel shake and abnormal noise.

Further, even in the case where the idle speed control device is provided, the engine speed is controlled to match the preset target speed, and the engine is not controlled in consideration of the vibration level. Therefore, there are problems that the engine vibration cannot be controlled sufficiently, and conversely, the number of revolutions is increased more than necessary and fuel economy is impaired.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an idle speed control device for an internal combustion engine capable of suppressing engine vibration while maintaining good fuel economy during idling. .

<Means for Solving Problems> Therefore, the present invention is configured to include an engine idle speed control means.

<Operation> The low vibration level area determination means determines the rotation speed area in which the engine vibration level detected by the engine vibration level detection means is equal to or lower than a predetermined value from the idle rotation speed area determined by the idle speed area determination means. .

The low fuel consumption region determination means selects a particularly low fuel consumption rotation speed region in the determined low vibration level region, and controls the engine rotation speed by the rotation speed control device so as to maintain the selected rotation speed region. To do.

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

A throttle valve 3 is provided in an intake passage 2 connected to the engine body 1, and an idle control valve 5 is provided in an auxiliary air passage 4 that bypasses the throttle valve 3 and is connected.

As the idle control valve 5, an electromagnetically driven type is used,
It is driven by inputting a pulse signal, and the valve opening can be controlled by variably controlling the duty ratio of the pulse.

An acceleration sensor 6 for detecting a vibration acceleration α of the wall of the intake passage 2 is attached to the outer wall of the intake passage 2.
The acceleration signal from the acceleration sensor 6 is input to the integrating circuit 7. The integrating circuit 7 integrates the detected acceleration signal to output a signal corresponding to the vibration velocity v.
This signal is further input to the second integrating circuit 8, and the integrating circuit 8 integrates the vibration velocity signal to output a signal corresponding to the signal amplitude f (vibration level).

That is, the acceleration sensor 6 and the two integrating circuits 7 and 8 constitute engine vibration level detecting means.

The vibration level signal is input to the control unit 9, which controls the vibration level signal and the engine speed signal from the crank angle sensor 10 for detecting the engine speed in the idle speed range. , The idle speed is controlled so as to reduce the engine vibration level while maintaining good fuel economy.

The control of the idle speed by the control unit 9 will be described below with reference to the flowchart shown in FIG.

In step (denoted as S in the figure) 1, the crank angle sensor 10
Based on a signal from the determining whether the idle speed range of the current engine speed N No ≦ N ≦ N ₁ (e.g., _{No = 600, N 1 = 700rpm} ).

The function of step 1 together with the crank angle sensor 10 constitutes an idle speed region determination means.

When it is determined that the engine speed is in the idle speed range, the routine proceeds to step 2, where the current engine speed is set as the speed Ns at the time when the control described later is started.

In step 3, it is determined based on the vibration level signal input from the integration circuit 7 whether the vibration level f is a low fuel consumption level less than the predetermined value fo.

When it is determined that it is less than the predetermined value fo, the routine proceeds to step 4, where it is determined that the engine speed N at this time is in the low vibration level region, and the flag F indicating the existence of the low vibration level region is set to 1, In step 5, the current engine speed N is stored as a region Nm.

When it is determined in step 3 that the vibration level f is equal to or higher than the predetermined value fo, the process proceeds to step 6 without storing this rotation speed region.

In step 6, from the current engine speed N to the predetermined speed ΔN
The value obtained by subtracting is calculated as the target speed Na to be controlled.

In step 7, it is determined whether the target rotation speed Na calculated in step 6 is equal to or less than No, which is the minimum rotation speed in the idle rotation speed region.

When it is determined that N> No, the process proceeds to step 8 and the engine speed N is controlled so as to be the target speed.

Specifically, the valve opening duty ratio of the energizing pulse signal to the idle control valve is gradually reduced, the current rotational speed is gradually reduced, and the current rotational speed is held at a position corresponding to the target rotational speed Na.

Next, returning to step 3, the vibration level is judged again, and if the vibration level is below a predetermined level, the storage area is determined by this rotation speed N.
When the value of Nm is updated and is equal to or greater than the predetermined value fo, the value is not stored and is again stored in step 6 from the current speed N to the predetermined speed Δ.
The rotation speed obtained by subtracting N is set as a new target rotation speed Na.

This control is repeated while the determination in step 7 is No, and when the target rotation speed Na becomes equal to or less than the minimum rotation speed No as a result, the routine proceeds to step 9 to control the engine rotation speed to keep the minimum rotation speed No.

Then proceed to step 10 to perform the vibration level determination again,
When the vibration level f is less than the predetermined value fo, the routine proceeds to step 11, where the number i of the memory rotational speed area is reset to 0 and this control is ended.

That is, even if the fuel consumption is kept at the minimum number of revolutions No. which is the best, the vibration level is still kept at a low level, so this state is maintained.

If the vibration level is determined to be equal to or higher than the predetermined value in step 10, the process proceeds to step 12 to determine whether the region number flag is 0, that is, the initial rotation speed Ns stored in step 2 Determine whether there is a low vibration level area while the rotation speed is being reduced. If the flag F is 1 (km), there is a low vibration level area. At this time, proceed to step 13. The engine speed is held in Nm which is selected and stored as the lowest speed in the low vibration level region, that is, the best fuel consumption.

When it is determined in step 12 that the flag F = 0, it means that there is no low vibration level region in the control for lowering the rotational speed, so this time the process proceeds to step 14 where the initial rotational speed Ns is read as N, and then step At 15, a value obtained by adding the predetermined rotation speed ΔN to this rotation speed N is set as the target rotation speed Na.

Next, in step 16, it is determined whether or not the target rotational speed Na is equal to or higher than the maximum rotational speed N _{1 in} the idle rotational speed region, and when it is equal to or higher than N ₁ , proceed to step 17 to perform a vibration level determination. Instead, the engine speed is maintained and controlled at the maximum speed N ₁ .

When it is judged at step 16 that Na <N ₁ , the routine proceeds to step 18, where the engine speed N is controlled to the target rotation speed Na, and then the routine proceeds to step 19 where the vibration level judgment is performed.

And when the vibration level is lower than fo,
It is not necessary to increase the number of revolutions anymore, so the current state is maintained.However, if fo or more, return to step 15 again, repeat the same operation until the vibration level becomes less than fo, and if Na ≧ N ₁ Is fixed at N ₁ .

By performing such control, it is possible to determine the low level region in which the vibration level is less than fo, and select the lowest rotation speed region, that is, the region with the best fuel consumption, and control to this region.

The functions of steps 3, 10, and 19 correspond to the low vibration level area determination means, the functions of steps 4 to 7, 11, 12, and 14 to 16 correspond to the low fuel consumption area selection means, and steps 8, 9, and 13 , 17,18
And the auxiliary air passage 4 and the idle control valve 5 constitute a rotation speed control means.

Further, normally, as the idle speed is decreased, the engine vibration level tends to increase, so when the vibration level f is determined to be fo or more in step 3 of FIG. 3, the engine speed is further decreased. Alternatively, a simple control configuration may be used in which the process proceeds to step 14 and subsequent steps to switch to the rotation speed increase control.

<Effects of the Invention> As described above, according to the present invention, the engine vibration level can be suppressed to a low level in the idling speed range while maintaining as low fuel consumption as possible, and steering wheel shake and abnormal noise are generated. The effect of being able to prevent is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is a flowchart showing an idle speed control routine of the same embodiment. 1 ... Engine body, 4 ... Auxiliary air passage 5 ... Idle control valve, 6 ... Acceleration sensor 7, 8 ... Integration circuit 9 ... Control unit 10 ... Crank angle sensor

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An idle speed range determining means for determining that the engine speed is in an idle speed range; an engine vibration level detecting means for detecting an output level of engine vibration; Low vibration level region determination means for determining a rotation speed region in which the engine vibration level is suppressed below a predetermined level, and particularly low fuel consumption in the rotation speed region of the low vibration level determined by the low vibration level region determination means. A low fuel consumption region selecting means for selecting a proper rotation speed region, and a rotation speed control device for controlling the engine speed so as to maintain the rotation speed region selected by the low fuel consumption region selecting means. A feature of an internal combustion engine idle speed control device.