JPH11200928A - Idling speed controller of vehicle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve unpleasant feeling in a torque variation by installing a self- propelling state detection means detecting a vehicular idle self-propelling state, and reducing a compensation value in time of feedback control over idling speed as compared with that in time of usual idling state at the time of detecting the idle self-propelling state. SOLUTION: At the time of idling speed feedback control by a control unit 25, first of all, when accelerator opening is in aidling state on the basis of a signal out of an accelerator sensor 26, an idling speed desired value is set up on the basis of a signal showing a transmission position and another signal showing an operating state of auxiliary load. A difference between this idling speed desired value and the actual speed is sought, then an injection quantity compensation value is found out on the basis of the speed difference, and this compensation value is added to a basic injection quantity and a fuel quantity to be injected is finally determined. In addition, when a vehicular driving system is judged as an idle self-propelling state, an idling fuel compensation value in time of this idle self-propelling state is determined, and the compensation value is added to the basic injection quantity and thereby a final idling time fuel injection quantity is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idling speed control device for a vehicle engine.

[0002]

2. Description of the Related Art In recent vehicle engines, the amount of fuel supplied and the amount of intake air during idling are corrected so that the actual rotational speed converges within an allowable range near a target rotational speed during idling. Thus, feedback control of the idle speed is performed.

[0003] By the way, the following points become problems in the vehicle engine that performs such feedback control of the idle speed. That is, in a state in which the engine is separated from the drive system and can freely rotate idle (this is referred to as a “normal idle state” in the present application), idle rotation control only causes rotation of the engine itself or torque fluctuation. In contrast, for example, when the vehicle is running in an idle state with the accelerator off, such as during a traffic jam (in this application, the vehicle driving state near idle rotation is referred to as “idle self-propelled state”). In addition, since the change in the engine torque due to the feedback control is transmitted to the vehicle as the change in the driving force, the change in the torque during the idle rotation control is easily felt by the occupant, and the smooth driving feeling is impaired.

[0004] In particular, in a vehicle equipped with a diesel engine, the low-speed torque is large due to the characteristics of the engine, and the torque fluctuation accompanying the idle rotation control is correspondingly large.

Japanese Unexamined Patent Publication No. Hei 3-107556 discloses an auxiliary load in order to reduce the occurrence of a traveling shock caused by turning on / off an auxiliary load such as an air conditioner for creep running in a vehicle with an automatic transmission. There is disclosed an apparatus in which the target value of the idling speed is gradually changed at the time of turning on and off the vehicle. However, only a gradual change of the target value in this manner causes a large torque when the actual idle speed is greatly deviated from the target value due to, for example, an increase in running resistance, since the target value is immediately followed. Changes are inevitable.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to solve the problem by reducing the amount of feedback correction of the idling rotation when the vehicle is running at the idling rotation.

[0007]

In order to solve the above problem, according to the first aspect of the present invention, the fuel supply amount at the time of idling is set such that the actual idle speed of the engine converges within an allowable range near the target speed. Alternatively, the idle speed control means for performing feedback control of the intake air amount, the self-propelled state detecting means for detecting the idle self-propelled state of the vehicle, and comparing the correction amount during the feedback control during the idle self-propelled state during the normal idle state. And a correction amount correcting means for reducing the amount.

According to a second aspect of the present invention, there is provided an idle speed control means for feedback-controlling the fuel injection amount during idling so that the actual idle speed of the diesel engine converges within an allowable range near the target speed, and Self-propelled state detection means for detecting an idle self-propelled state, and correction amount correction means for reducing the injection amount correction amount during the feedback control during the idle self-propelled state as compared with the normal idle state are provided.

According to a third aspect of the present invention, the correction amount correcting means according to the first or second aspect of the present invention comprises a P component (proportional component) and an I component provided by the idle speed correcting device as a correction amount at the time of feedback. At least I of (integral) is reduced in the idle self-running state.

According to a fourth aspect of the present invention, in the third aspect of the invention, the idle speed control means initializes the I component to a predetermined value at the time of transition from the idle self-running state to the normal idle state. The configuration is as follows.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the idle speed control means performs feedback control at the time of transition from the normal idle state to the idle self-running state with the I component immediately before the transition as an initial value. Configure to do so.

According to a sixth aspect of the present invention, the self-propelled state detecting means according to the first or second aspect of the present invention includes a means for detecting an accelerator opening and a means for detecting at least one of a vehicle speed and an engine speed. Means for detecting a state in which the engine driving force is transmitted to the axle side, wherein the accelerator opening is equal to or less than a predetermined reference value, and the vehicle speed or the engine speed is equal to or more than the predetermined reference value, and the engine is driven. When the force is transmitted to the axle side, it is determined that the vehicle is in the idle self-running state.

[0013]

According to the above inventions, the feedback correction amount of the idling speed is reduced in the idling self-running state, so that the change in the engine speed or the torque toward the target value becomes gentler. The torque fluctuation perceived by the occupant as a reaction from the drive system is reduced, and a smooth driving feeling is exhibited.

In particular, in a vehicle equipped with a diesel engine, the effect of torque fluctuation during idling is large,
According to the invention, the driving feeling in the idle self-propelled state is remarkably improved.

When the idling speed is controlled by the PID, the control accuracy and the responsiveness can be improved by appropriately adding the I component as a correction amount at the time of normal idling in which the engine can freely rotate, but the resistance from the driving system can be improved. This may cause erroneous learning in an idle self-running state in which rotation fluctuation may occur due to such disturbance. In this regard, according to the third aspect of the invention, since the I component is reduced, such a problem can be avoided while reducing the correction amount.

Further, the PID of such an idle speed is
In the control, according to the fourth aspect of the invention, when the state shifts from the idle self-running state to the normal idle state, the value of I is initialized to a predetermined value. As a result, the erroneous learning operation described above can be avoided, and when the actual idle speed is likely to suddenly change with the transition to the normal idle state, it can be quickly converged to the target value.

On the other hand, according to the invention of claim 5, when shifting from the normal idle state to the idle self-running state,
Feedback control is performed using the I component immediately before the transition as an initial value. This makes it possible to smoothly transition from the normal idle state to the idle self-propelled state.

According to the sixth aspect of the present invention, even in the idle running state, the control for reducing the correction amount is not performed in an operating range where the vehicle speed or the engine speed is low. Under low-speed conditions, the engine may stall when the running resistance suddenly increases due to the road surface condition. However, according to the present invention, the normal idle speed control is performed under such conditions, resulting in high responsiveness characteristics. To reduce the risk of stalls.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a diesel engine to which the present invention can be applied.

In FIG. 1, 10 is an engine body of a diesel engine, 11 is an intake passage, 12 is an exhaust passage,
The intake air is supercharged by the turbocharger 13. Reference numeral 14 denotes an exhaust gas recirculation passage.
The amount of exhaust gas recirculated to 1 is controlled. At the time of exhaust gas recirculation, a throttle valve 16 provided in the intake passage 11 is used.
Squeeze.

A fuel injection valve 18 for injecting fuel into a combustion chamber 17 of the engine body 1 is provided, and fuel from a fuel injection pump 19 is supplied to the fuel injection valve 18. The fuel injection pump 19 rotates the plunger 2 in synchronization with the engine speed.
0 operates to increase the pressure of the fuel pre-pressed by the feed pump 21 and feed the fuel to the fuel injection valves 18 of the respective cylinders near the compression top dead center. The fuel injection amount changes depending on the position of the control sleeve 22 and is operated by a signal from the control device 25. A rotary solenoid (electric governor)
23 controls the position of the control sleeve 22.

A control device 25 comprising a microcomputer receives a signal from an accelerator sensor 26 for detecting an accelerator opening and an engine speed signal, and calculates a basic fuel injection amount according to the accelerator opening and the speed. Based on this, the rotary solenoid 23 is controlled.

In order to correct the basic injection amount and control the exhaust gas recirculation amount, the control device 25 composed of a microcomputer transmits signals representative of the operating state, such as the accelerator opening and the rotational speed, as well as the engine speed. A top dead center position signal from a sensor (TDC sensor) 27 for detecting the top dead center position, a vehicle speed signal, and a transmission position signal from a transmission switch are input. Furthermore, the fuel injection pump 19
A sensor 29 for detecting a control sleeve position for measuring an actual fuel injection amount, a signal from a sensor 30 for detecting fuel temperature, a sensor 31 for detecting a needle lift amount of the fuel injection valve 18 of the engine body 1, A signal from the sensor 32 for detecting the engine cooling water temperature is also input. Further, an air flow meter 33 for detecting a mass flow rate of the engine intake air is attached to the intake passage 11, and the intake air signal is also input.

The control device 25 controls the fuel injection timing according to the operating state.
5, the pressure applied to the timer piston 36 is changed. Further, in order to prevent fuel leakage, the fuel cut valve 37 is closed when the engine is stopped. further,
The duty control of the negative pressure control valve 34 for controlling the driving negative pressure of the exhaust gas recirculation control valve 15 and the opening degree of the first solenoid valve 38 and the second solenoid valve 39 for simultaneously controlling the driving voltage of the throttle valve 16 are controlled. Thus, optimal exhaust gas recirculation is performed in accordance with the operation state in order to reduce NOx.

Next, an outline of the idle speed feedback control by the control device 25 will be described. In this control, based on a signal from the accelerator sensor 26, it is determined that the engine is in the idle state when the accelerator opening is at the fully closed position. Judgment, and then, in addition to the coolant temperature, start switch, battery voltage, a signal indicating the position of the transmission, a signal indicating the operating state of auxiliary equipment loads such as an air conditioner and power steering, and the operating state of electric loads such as lights The target value of the idle speed is set based on a signal indicating the above. Then, a difference between the idle speed target value and the actual speed is obtained, and based on the speed difference, an injection amount correction amount is obtained by, for example, PID control. The amount of fuel to be determined is determined, and the position of the rotary solenoid 23 is controlled while feeding back the control sleeve position by a signal from the sensor 29 so that the amount of fuel is obtained.

FIG. 2 is a flowchart showing the content of the fuel injection amount control according to the embodiment of the present invention including such a basic idle speed feedback control portion. First, at step 201, a basic injection amount of fuel to be supplied to the engine is determined. This is determined, for example, by reading or calculating from a storage device set to give a predetermined injection amount value based on the accelerator opening and the engine speed.

Next, at step 202, the accelerator opening is determined based on the signal from the accelerator sensor 26. Here, when the accelerator opening is smaller than a predetermined reference value, it is determined that the vehicle is in the idle state, and the control enters the idle speed correction control in step 203 and subsequent steps. On the other hand, when the opening degree of the idle exceeds the reference value, the idle correction amount is not performed (idle correction amount = 0, step 208) because the state is the non-idle state.

In step 203, whether or not the engine rotation is transmitted to the vehicle drive system is determined based on signals from various sensors. For example, in the case of a vehicle with an automatic transmission, since the position of the selector lever is in a travel range such as the D range, it is determined that the vehicle drive system is in an idle self-propelled state driven by an engine. In the case of a vehicle with a manual transmission, it is determined that the vehicle is in the idle self-propelled state when the clutch is connected and the transmission shift lever is located at a position other than neutral. If it is determined that the vehicle drive system is not driven by the engine, the engine is in the normal idle state in which the engine can be freely idled. The feedback correction amount is determined. In step 209, the feedback correction amount is added to the basic injection amount to determine the final idle fuel injection amount, and the idle speed is controlled near the target value (see FIG. 3).

If it is determined in step 203 that the vehicle drive system is in the idling self-propelled state driven by the engine, then in steps 204 and 205, the vehicle speed V and the engine speed Ne are determined, respectively. You. here,
For example, when the vehicle speed V is 8 km / h or more and the engine speed Ne is 3
If it is not less than 00 rpm, the routine proceeds to step 206, where the idle fuel correction amount in the idle self-running state is determined.

As the correction in the idle self-running state, the correction amount to be added to the basic injection amount is reduced. For this, in the case of PID control, I
Decrease or zero the minute (see FIG. 4). This is because, during normal idling, the effect of learning the deviation from the target value can be obtained by appropriately adding the I component to improve the accuracy and responsiveness of the idle speed control, but the resistance from the drive system can be improved. This is because in an idle self-running state in which rotation fluctuation may occur due to disturbance, this may cause erroneous learning.

The correction amount in the idle self-propelled state determined in this way is added to the basic injection amount in step 209 to obtain a final idle fuel injection amount. By the control of reducing the feedback correction amount added to the basic injection amount during the idle self-running state, the change in the fuel injection amount for each correction, that is, the torque fluctuation is alleviated accordingly. The sense of discomfort experienced is reduced, and a smooth driving feeling is obtained.

On the other hand, in the determinations after step 204, the vehicle speed V is less than 8 km / h or the engine speed Ne is 3
If the speed is less than 00 rpm, the routine proceeds to step 207, where normal idling correction control, that is, control for not reducing the correction amount, is performed.
This is because under such extremely low-speed conditions, the engine may stall when the running resistance suddenly increases due to the road surface condition. Therefore, it is better to secure a certain amount of correction and give priority to responsiveness. .

By the way, the PI of the idle speed described above is
In the D control, when shifting from the idle self-running state to the normal idle state, it is preferable to initialize the value of I to a predetermined value (a fixed value or a value immediately before shifting to the idle self-running state). This avoids the erroneous learning operation described above, and may cause a sudden change in the actual idle speed when the driving force is released with the transition to the normal idle state.
In such a case, the I component is secured so that the target value can be quickly converged. On the other hand, when shifting from the normal idle state to the idle self-running state, by performing the feedback control with the I value immediately before the shift as an initial value, it is possible to smoothly shift to the idle self-running state.

Although the embodiment has been described with reference to an application to a diesel engine, it goes without saying that the present invention is also applicable to a spark ignition type engine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a diesel engine to which an embodiment of the present invention is applied.

FIG. 2 is a flowchart showing control contents of an embodiment of the present invention.

FIG. 3 is a control characteristic diagram showing a feedback control operation in a normal idle state.

FIG. 4 is a control characteristic diagram showing a feedback control operation in an idle self-running state.

[Explanation of symbols]

 Reference Signs List 10 Main body of diesel engine 11 Intake passage 12 Exhaust passage 13 Turbocharger 14 Exhaust recirculation passage 15 Exhaust recirculation control valve 16 Throttle valve 17 Combustion chamber 18 Fuel injection valve 19 Fuel injection pump 25 Control device 26 Accel sensor 33 Air flow meter

Claims (6)

[Claims] An idling speed control means for feedback-controlling a fuel supply amount or an intake air amount during idling so that an actual idling speed of the engine converges within an allowable range near a target speed; A vehicle engine comprising: a self-propelled state detecting means for detecting a running state; and a correction amount correcting means for reducing a correction amount at the time of the feedback control during an idle self-propelled state as compared with a normal idle state. Idle speed control device. 2. An idle speed control means for feedback-controlling a fuel injection amount during idling so that an actual idle speed of a diesel engine converges within an allowable range near a target speed. A self-propelled state detecting means for detecting, and a correction amount correcting means for reducing an injection amount correction amount at the time of the feedback control during an idle self-propelled state as compared with a normal idle state. Idle speed control device. And a correction amount correction means for correcting the amount of P given by the idle speed correction means as a correction amount at the time of feedback.
3. The idling speed control device for a vehicle engine according to claim 1, wherein at least I is reduced during the idle self-running state. 4. The system according to claim 1, wherein the idle speed control means is configured to initialize the I component to a predetermined value at the time of transition from the idle self-running state to the normal idle state. 3. The idle speed control device for a vehicle engine according to claim 3. 5. The system according to claim 1, wherein the idle speed control means is adapted to switch the I / O just before the transition from the normal idle state to the idle self-running state.
4. The idle speed control device for a vehicle engine according to claim 3, wherein the feedback control is performed with the minute as an initial value. 6. The self-propelled state detecting means includes means for detecting an accelerator opening, means for detecting at least one of a vehicle speed and an engine speed, and means for detecting a state in which engine driving force is transmitted to an axle side. When the accelerator opening is smaller than a predetermined reference value, the vehicle speed or the engine speed is equal to or higher than the predetermined reference value, and the engine driving force is transmitted to the axle side, the idle self-running state is provided. The idling speed control device for a vehicle engine according to claim 1, wherein the idling speed control device is configured to determine the idling speed.