JPH0828330A - Idle rotation speed control method - Google Patents

Abstract

PURPOSE:To check the occurrence of shortage of a suction air quantity by comparing a feedback correction quantity at load changing time, a learing correction quantity and a feedback correction quantity at that time with each other, and setting a correction quantity becoming largest as a compared result as an initial quantity of a feedback correction value after a condition changes to a no-load condition. CONSTITUTION:Whether or not a condition changes to an AT (automatic transmission) no-load condition is judged from a shift signal (p) outputted from a shift position switch 20. When it changes to the no load condition, a feedback correction quantity at that time, a stored feedback correction quantity at changing time and a learning value are compared with each other, and the largest one is set as an initial quantity of a feedback correction quantity of this time. Operation is performed on the operation duty ratio being a control value of a flow rate control valve 4 of a bypass passage 3. As a result, since opening of the flow rate control valve 4 is not suddenly reduced, engine speed is not reduced when a load condition of an AT changes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates mainly to an idle speed control method for an automobile engine equipped with an automatic transmission, that is, an automatic transmission.

[0002]

2. Description of the Related Art Conventionally, in an automobile engine equipped with an automatic transmission (hereinafter referred to as AT), a flow control valve is provided in a bypass passage bypassing a throttle valve, and the opening degree of the flow control valve is controlled. It is known to control the intake air amount during idling so that the intake air amount is adjusted to absorb the change in the engine speed when the AT load changes. For example, in Japanese Unexamined Patent Publication No. 3-88934, the duty ratio during feedback control when the air conditioner is turned on and the duty ratio during feedback control when the air conditioner is turned off are stored, and at the moment when the state of the air conditioner changes. There is described a method for controlling the idling speed in which the flow control valve is controlled by the stored duty ratio regardless of the duty ratio up to that point.

[0003]

However, in the above, when the air conditioner is turned on and off, the duty ratio stored at that time is always used.
For example, if the vehicle continuously moves to a highland where the atmospheric pressure is low after traveling on the flatland, if the duty ratio on the flatland is applied, the intake air amount becomes insufficient and the air conditioner is turned on. , There is a possibility that the number of rotations does not rise sufficiently, or that the rotation may drop when it is turned off. In other words, the duty ratio during the feedback control when the air conditioner is turned on and the duty ratio during the feedback control when the air conditioner is turned off are stored in the idle operation place and the idle operation place using the value, When there is a difference in temperature or atmospheric pressure, the amount of air passing through the bypass passage is small, and thus the intake air amount may be insufficient.

An object of the present invention is to eliminate such a problem.

[0005]

In order to achieve the above object, the present invention takes the following measures. That is, the idle speed control method according to the present invention is provided with a flow rate control valve in a bypass passage bypassing the throttle valve, and the opening degree of the flow rate control valve is adjusted to at least the feedback correction amount and the learning correction according to the operating state at idling. It is an idle speed control method that controls the engine speed when the load changes by controlling the control value calculated using the quantity and correcting the control value when the load status changes. It stores the change-time feedback correction amount when it changes, detects that the loaded state has changed to the unloaded state, and detects the change from the loaded state to the unloaded state, the changing feedback correction amount. And the learning correction amount and the feedback correction amount at that time are compared,
It is characterized in that the maximum correction amount as a result of the comparison is set as the initial amount of the feedback correction amount after the change to the no-load state.

[0006]

With such a structure, when the loaded state by the AT or the air conditioner (hereinafter referred to as an air conditioner) is changed to the unloaded state, the feedback correction amount at the time of change and the learning correction amount and The maximum value of the feedback correction amount at the time point is the initial amount of the feedback correction amount in the no-load state.
Normally, after changing from the no-load state to the loaded state, the control value is increased to increase the amount of air flowing through the bypass passage.However, if the idle speed increases too much due to the increase, it will cause a problem. However, when there is no load, the maximum value becomes the initial amount of the feedback correction amount as described above, so there is a change in the control value, that is, when the load is applied and when it is turned off. The amount of difference in the feedback correction amount of is set to the minimum.

Therefore, the feedback correction amount rises faster than the case where the feedback correction amount is lowered when there is a load and is increased in accordance with the operating state after changing to no load. ,
There is no drop in rotation when changing to no load. That is,
The feedback correction amount is set from the largest value of the feedback correction amount at the time of change, the learning correction amount, and the feedback correction amount at that time, so the control value is compared with that by the feedback correction amount that decreased while there was a load. Then, the opening of the flow control valve increases. As a result, the intake air amount is increased, and the drop in rotation when the no-load state is achieved is eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The engine schematically shown in FIG. 1 is for an automobile. The intake system 1 is provided with a throttle valve 2 which opens and closes in response to an accelerator pedal (not shown), and bypasses the throttle valve 2. Vice passage 3
The bypass passage 3 is provided with a flow control valve 4 for idle speed control. The flow rate control valve 4 is of an electronic opening / closing type, which is abbreviated as a large flow rate VSV, and controls the operation duty ratio DISC of the drive voltage applied to the terminal 4a, which is a control value, to control the flow rate per unit time. The degree of opening can be changed so that the flow rate of air in the bypass passage 3 can be adjusted. In other words, one set of the bypass passage 3 and the flow control valve 4 normally forms a single bypass passage for each correction item in the feedback control during idling.

The operation duty ratio DISC
Includes those things, for example, the correction amount DS at the time of starting
TA, water temperature correction amount DAAV, feedback correction amount DF
B, learning correction amount DLRN, AT load correction amount DSET _AT
The variable range is limited so that each correction item such as is not extremely increased or decreased by being added. The feedback correction amount DFB is a correction amount calculated according to the engine speed NE, and for example, during idle operation, fuel cut during deceleration is not performed, and the vehicle speed is 2 km / h or less. Then, the intake pressure sensor 13,
When the water temperature sensor 17 and the vehicle speed sensor 15 are all operating normally, the feedback control is executed and calculated. The learning correction amount DLRN is set by calculating the feedback correction amount DFB in a predetermined cycle, and the calculation method itself may be one widely used in the field. The feedback correction amount DFB is calculated immediately after starting, whereas the learning correction amount DLRN is calculated after complete warm-up.

The intake system 1 is further provided with a fuel injection valve 5, and the fuel injection valve 5 and the flow rate control valve 4 are controlled by an electronic control unit 6.

The electronic control unit 6 includes a central processing unit 7
And a storage device 8, an input interface 9, and an output interface 11 are mainly configured. Therefore, the input interface 9 has an intake pressure signal a output from an intake pressure sensor 13 for detecting the pressure in the surge tank 12 and a rotation speed output from a rotation speed sensor 14 for detecting the engine speed NE. The signal b, the vehicle speed signal c output from the vehicle speed sensor 15 for detecting the vehicle speed, the opening signal d output from the throttle sensor 16 for detecting the open / closed state of the throttle valve 2, and the engine temperature as the engine temperature. Water temperature sensor 1 for detecting cooling water temperature
The water temperature signal e output from 7 and the shift signal p output from the shift position switch 20 for detecting the shift position of the AT are input. Further, from the output interface 11, a drive signal f corresponding to the calculated fuel injection time is supplied to the fuel injection valve 5, and a calculated duty ratio DIS to be described later is supplied to the flow rate control valve 4.
The control signal g based on C is output.

Although not shown, the electronic control unit 6 has a built-in A / D converter for converting an input analog signal into digital data, and keeps the atmospheric pressure signal h and the water temperature signal e constant. It is converted into digital data at intervals and output to the central processing unit 7. As the AT itself, one widely known in this field can be used. For example, the AT can be selected depending on the vehicle speed and the output of the engine, such as a fluid torque converter, an auxiliary transmission having a three or four gear ratio. It may be provided with a control system for automatically controlling the shift.

The electronic control unit 6 determines the fuel injection valve opening time based on the respective signals from the intake pressure sensor 13 and the rotation speed sensor 14 as main information, and controls the fuel injection valve 5 based on the determination to determine the load. The program for injecting the fuel corresponding to the above from the fuel injection valve 5 to the intake system 1 is built in. Further, in the engine connected to the AT, a flow rate control valve 4 is provided in a bypass passage 3 that bypasses the throttle valve 2, and the opening degree of the flow rate control valve 4 is learned at least as a feedback correction amount according to an operating state during idling. The AT is controlled by the control value calculated using the correction amount and
When the load condition of changes, the control value is corrected to control the engine speed NE when the load changes.
The feedback correction amount at the time of change to the loaded state of the AT is stored, the change of the loaded state of the AT to the unloaded state is detected, and the change from the loaded state to the unloaded state is detected. At this time, the feedback correction amount at the time of change, the learning correction amount and the feedback correction amount at that time are compared, and the maximum correction amount as a result of the comparison is set as the initial amount of the feedback correction amount after the change to the no-load state. It also has a built-in program to set it.

A schematic structure of this idle-up control program is shown in FIG.

First, in step S1, the AT signal is output from the shift signal p output from the shift position switch 20.
It is determined whether or not the state has changed to the loaded state, and if the state has changed to the loaded state, the process proceeds to step S2. In step S2, the change feedback correction amount DFB _ON at that time is stored. In step S3, it is determined from the shift signal p whether the AT is unloaded or not. If the AT is unloaded, the process proceeds to step S4. If not, the process proceeds to another routine. In step S4, the feedback correction amount DFB at that time is compared with the stored feedback correction amount DFB _ON and the learned value DLRN, and the largest value among them is the initial amount of the current feedback correction amount DFB. And Then, the calculated duty ratio DISC which is the control value of the flow rate control valve 4 in the bypass passage 3
Is calculated by the following equation.

DISC = DSTA + DFB + DAAV + DSET _AT In such a configuration, when the AT is changed from the neutral range to the drive range when idling,
The shift position switch 20 operates and the shift signal p
Is turned on, the control is performed from step S1 to step S2.
Then, the feedback correction amount DFB at the time when the AT load state changes is stored in the storage device 8. in this case,
Since AT becomes a load, the calculation duty ratio DISC is A
By adding the T load correction amount DSET _AT, it becomes larger than the previous value, and as shown in FIG. 3, the opening degree of the flow control valve 4 becomes large and the engine speed NE rises. At the same time, the feedback correction amount DFB is
As the engine speed NE increases, it decreases.

After that, when the state changes to the AT no-load state, the calculated duty ratio DISC becomes the AT load correction amount DSET _AT.
Becomes 0 and becomes smaller, and accordingly, the engine speed NE begins to change so as to decrease. On the other hand, the control is performed in step S1 →
The process proceeds from step S3 to step S4. As the feedback correction amount DFB, the largest one of the feedback correction amount DFB at that time point, the stored feedback correction amount DFB _ON and the learning value DLRN is adopted, and the calculation is performed. The duty ratio DISC is calculated.

Therefore, if the AT load condition continues for a long time and the feedback correction amount DFB greatly decreases during that period, the decreased feedback correction amount DFB is AT.
It is no longer used when there is no load, and the calculation duty ratio DISC does not become extremely small. As a result, the opening degree of the flow control valve 4 does not suddenly decrease, and the engine speed NE does not drop when the AT load condition changes.

The present invention is not limited to the embodiment described above. For example, in the above embodiment, the case where the AT changes from the neutral range to the drive range has been described, but such a load may be an air conditioner. In this case, instead of determining the load change based on the shift signal p in the above embodiment, the load change may be determined based on the ON / OFF signal of the air conditioner.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0022]

As described in detail above, the present invention, when the load is removed, even if the feedback correction amount at that time is an inappropriate value, the change feedback correction amount and the learning correction amount are changed. Since the largest value of the feedback correction amount at that time and the feedback correction amount at that time is adopted as the initial amount of the feedback correction amount in the subsequent control, the initial value of the feedback correction amount is always set large and the control value becomes large, Therefore, the opening degree of the flow control valve can be increased, the amount of air passing through the bypass passage increases,
It is possible to reliably prevent the rotation from decreasing.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of the embodiment.

FIG. 3 is an operation explanatory view of the same embodiment.

[Explanation of symbols]

 2 ... Throttle valve 3 ... Bypass passage 4 ... Flow control valve 6 ... Electronic control device 7 ... Central processing unit 8 ... Memory device 9 ... Input interface 11 ... Output interface 20 ... Shift position switch

Claims (1)

[Claims] 1. A control in which a flow control valve is provided in a bypass passage bypassing a throttle valve, and the opening of the flow control valve is calculated using at least a feedback correction amount and a learning correction amount in accordance with an operating state during idling. It is an idle speed control method that controls the engine speed when the load changes by controlling the value based on the value and correcting the control value when the load status changes.Feedback correction during change when the load status changes The amount is stored, when the change from the loaded state to the unloaded state is detected, and when the change from the loaded state to the unloaded state is detected, the change feedback correction amount and the learning correction amount and at that time It is characterized in that the maximum amount of correction as a result of comparison is set as the initial amount of the feedback correction amount after the change to the no-load state. Idle speed control method.