JPH0315015B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an engine idle speed control device,
In particular, the present invention relates to an engine idle speed control device that supplies intake air for load correction during load operation.

(Prior art) In automobile engines, etc., in order to improve fuel efficiency and exhaust performance during idling, it is possible to feedback control the engine speed to a predetermined target speed by adjusting the amount of intake air. However, in this type of feedback control, if you try to increase the response more than necessary, hunting will occur and the stability of the control will be impaired. Integral control is employed in which the ratio of the amount of air, that is, the gain, is set relatively small. However, with such integral control with a small gain, when the engine speed suddenly changes due to external load operation, etc., the engine speed quickly reaches the target due to poor control response. Problems will occur if the rotation speed does not return to normal. Therefore, for example,
As disclosed in Japanese Patent No. 98413, a predetermined amount of intake air for load correction is supplied to the engine during load operation, which is different from the intake air supplied by the feedback control. According to such a method, it can be expected that a drop in engine speed due to load operation and engine stalling caused by this can be prevented.

However, in the past, the amount of intake air supplied for load correction was the same for each load of different types, or was set to be a different amount depending on the type of load, but the amount of intake air supplied for each load was Because it was set uniformly, the following problems occurred.

In other words, a fixed amount of intake air is supplied to compensate for the load when operating an air conditioner whose load varies depending on the temperature, or a power steering system whose load varies depending on the steering amount or speed of the steering wheel. However, the amount of intake air supplied may not correspond to the load of the air conditioner, power steering, etc., and as a result, the amount of intake air may be insufficient and the engine speed may not return quickly, or the amount of intake air may be insufficient. If the engine speed is too high, a situation such as an increase in the engine speed may occur, and stable idle control will not be performed. In particular, when a car equipped with an automatic transmission is running at low speed at idle, the amount of intake air supplied for load correction is too large for the power steering load, which varies depending on the steering speed of the steering wheel, etc. In this case, there is a risk that the engine speed will rise more than necessary and the car will fly out of the way, contrary to the driver's expectations.

(Object of the invention) The present invention provides an engine idle speed control device,
In order to prevent the engine speed from dropping especially when a load is applied to the engine, the idle rotation system supplies a predetermined amount of intake air for load compensation in addition to the intake air supplied by normal feedback control. This is to deal with the above-mentioned problems in the engine speed control device, and the amount of intake air for load correction is variably controlled so as to decrease as the engine speed increases. As a result, when the air conditioner, power steering, etc., whose loads vary depending on the operating conditions, etc., operate, the engine speed changes to the target rotation speed that would occur if the intake air amount for load correction was set to a constant value. In addition to ensuring stable idle control by preventing recovery delays and engine racing, this system also prevents power steering from occurring at low speeds, especially in vehicles equipped with automatic transmissions.
The purpose of this invention is to prevent the vehicle from jumping out of the way when the amount of intake air for load correction is too large for the magnitude of the load that changes depending on the steering speed of the steering wheel and the like.

(Configuration of the Invention) In order to achieve the above object, the engine idle speed control device according to the present invention is characterized by being configured as follows.

That is, as shown in FIG. 1, the intake air amount adjusting means B adjusts the amount of intake air passing through the intake passage A during idling, and the actual engine speed detected by the engine speed detecting means C. An engine idle speed control device comprising feedback control means D that controls the intake air amount adjusting means B based on the deviation from the target idle speed to converge the actual engine speed to the target idle speed,
A load detecting means E for detecting the operation of the load, and the above-mentioned suction device for supplying a predetermined amount of intake air for load correction separately from the control by the feedback control means D when the load detecting means E detects the operation of the load. A load correction intake air supply means F for controlling the air amount adjustment means B, and a control means G for adjusting the control amount of the load correction intake air supply means F are provided. The control means G controls the amount of intake air for load correction supplied by the intake air supply means F for load correction when the load is operated.
The higher the engine speed detected by

Therefore, when operating a load whose size is not uniformly determined, if the load is large and the engine speed drops significantly, a large amount of load correction intake air is supplied to reduce the engine speed. If the target rotational speed reliably and quickly increases to the target rotational speed, and the load is small, and therefore the drop in engine rotational speed is relatively small, the amount of air supplied is small and the engine rotational speed does not become excessive. rising is prevented.

In addition, in FIG. 1, a bypass passage that bypasses the throttle valve H in the intake passage A is shown.
Although the control valve B ₁ provided in A ₁ and the actuator B ₂ that drives it are used as the intake air amount adjusting means B, the throttle valve H is driven by the actuator, and this can also be used as the intake air amount adjusting means. good.

(Effects of the Invention) According to the above configuration, in the engine idle speed control device which supplies a predetermined amount of intake air for load correction in addition to the supply of intake air by normal feedback control when the load is operated. ,
The supply amount of the intake air for load correction is variably controlled so that it decreases as the engine speed increases, so when operating air conditioners, power steering, etc. whose loads vary depending on the operating conditions, etc. If the engine speed decreases significantly, a large amount of the intake air for load correction is supplied to prevent engine stalling, and the engine speed is reliably and quickly returned to the target speed. If the decrease in engine speed is small, the amount of air supplied is set to a small amount, preventing the engine speed from rising, and stable idle control is performed. Especially in cars with automatic transmissions,
When the power steering is activated while driving at low speed due to idling in the D range, the load acting on the engine is small because the steering speed of the steering wheel is small, and therefore a large amount of load is applied even though the engine speed decreases little. By supplying the correcting intake air and causing the engine speed to rise excessively, problems such as the car launching contrary to the driver's expectations can be prevented.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

As shown in FIG. 2, an intake passage 5 and an exhaust passage 6 are communicated with the combustion chamber 2 of the engine 1 via intake and exhaust valves 3 and 4, respectively. In the intake passage 5, an air flow meter 7, a throttle valve 8, and a fuel injection nozzle 9 are arranged from the upstream side, and between the upstream side and the downstream side of the throttle valve 8 in the intake passage 5. A bypass passage 10 for idle control is provided, and an electromagnetic control valve 11 for adjusting the flow rate of air passing through the passage 10 is installed on the bypass passage 10. Incidentally, the exhaust passage 6 is provided with a catalytic converter 12 for removing harmful components of exhaust gas.

On the other hand, this engine 1 includes a fuel control section ₁₃₁ that outputs a fuel control signal a to the fuel injection nozzle 9 to control the fuel injection amount, and an idle control section 131 that outputs an idle control signal b to the electromagnetic control valve 11 during idle. a feedback control unit 13 ₂ that feedback-controls the engine rotation speed to the target rotation speed by adjusting the flow rate of air passing through the bypass passage 10;
A load correction unit 13 ₃ that outputs an idle control signal b to the electromagnetic control valve 11 to increase the air flow rate when the load operates during idle, and a load correction control that adjusts the amount controlled by the load correction unit 13 ₃ . a control unit 13 having a section ₁₃₄ ;
is provided. The fuel control unit 13 ₁ includes an engine rotation sensor 14 that detects the engine rotation speed.
In response to the rotational speed signal c from the airflow meter 7 and the air flow rate signal d from the airflow meter 7, the air-fuel ratio is
The control value of the fuel control signal a is set to be 14.7. The feedback control section 13 ₂ also receives a throttle opening signal e from a throttle opening sensor 15 that detects the opening of the throttle valve 8 and an engine rotational speed signal c.
When it is determined that the operating state of the engine 1 is in the idle region based on The feedback control amount, that is, the opening/closing time ratio (duty ratio) of the electromagnetic control valve 11 is determined according to the deviation from the actual engine rotation speed indicated by the rotation speed signal c.
is set, and this set value is output to the electromagnetic control valve 11 as an idle control signal b. Furthermore, the load correction section 13 ₃ includes an air conditioner,
A load correction amount is set based on a load signal g from a load sensor 17 that detects the operation of loads such as power steering and lights, and this correction amount is output to the electromagnetic control valve 11 as an idle control signal b. It's summery.

However, the load correction control unit 13 ₄ adjusts the load correction amount by the load correction unit 13 ₃ based on the engine rotation speed signal c, and when the load is activated, the engine rotation speed is higher than the target rotation speed. If the engine rotation speed becomes lower than the target rotation speed, the load correction amount is decreased, and if the engine speed becomes lower than the target rotation speed, the correction amount is increased.

Next, the operation of the control unit 13, particularly the feedback control section 13 ₂ , the load correction section 13 ₃ and the load correction control section 13 ₄ will be explained according to the flowchart of FIG.

First, the control unit 13
In step _X1 , the engine speed N and throttle opening indicated by the engine speed signal c and throttle opening signal e are read, and in _step
Based on the opening degree, it is determined whether the engine 1 is in the idle region. As a result, if the water temperature is in the idle region, the control unit 13 controls the solenoid control valve 1 based on the water temperature signal f in step _X3 .
The basic control amount (duty ratio) _D0 for 1 is calculated, and then in _step If none of the above loads are operating, set the total load correction amount (duty ratio) _D1 to 0 in step _X5 .
Set to . On the other hand, if it is determined in step _X4 that the load has been activated, the control unit ₁₃ determines in step If not, the power steering _load correction amount D _{1 ′} is set to ₀ in _step Then, the total load correction amount D _{1 is determined by adding the power steering load correction amount D 1} ′ (in this case, D ₁ ′=0) and other load correction amounts D _{1 ″} .

Next, the control unit 13
At X ₁₀ , set the target rotation speed N ₀ according to the warm-up state of the engine 1 based on the water temperature signal f, and then execute steps X ₁₁ to X ₁₄ to set the feedback control amount.
Calculate D ₂ . In other words, as a result of comparing the actual engine rotation speed N and the rotation speed obtained by adding the predetermined dead zone α to the target rotation speed _N0 , the engine rotation speed N
If is larger, step from step X ₁₁
Execute X ₁₂ and set engine speed N and target speed N ₀
The control amount ΔD ₂ corresponding to the deviation from the previous deviation is subtracted from the feedback control amount D ₂ which is the integral value of the control amount corresponding to the previous deviation, and this subtracted value is used as the new feedback control amount (duty ratio) D ₂ Set as . Also, the engine speed N is the target speed
If _the engine rotational speed N is smaller than the value obtained by subtracting the deadband α from the target rotational speed _N0 , step _X13 to step _X14 are executed; The control amount ΔD ₂ corresponding to the deviation between the engine rotation speed N and the target rotation speed N ₀ is added to the previous feedback control amount D ₂ , and this added value is used as the new feedback control amount.
Set as _D2 . Incidentally, if the engine speed N is within the dead band α, the previous feedback control amount _D2 is used as the new control amount _D2 . When each control amount is set in this way, the control unit 13 adds the basic _control amount D0, the full load correction amount _D1 , and the feedback control amount _D2 to the final control amount Dx in step _X15 . After that, in step _X16 , this final control amount Dx is outputted to the electromagnetic control valve 11 as the idle control signal b. Then, while the operating range of the engine 1 is in the idle range, the control unit 13 repeats the processing of steps _X1 to _X16 .

By the way, the magnitude of the load that acts on the engine when various external loads are activated is always approximately constant regardless of the operating state for external loads other than power steering, such as lights, so the above steps are not applicable.
The other load correction amount D _{1 ″} calculated by As the magnitude of the load fluctuates, if the load compensation amount is set to a constant value, as with the operation of the other external loads mentioned above, this constant load compensation amount may not correspond to the varying magnitude of the load. occurs, thereby impairing the stability of the idle control.However, in the control unit 13, the following processing is performed in order to avoid the above-mentioned problems.

That is, if it is determined that the load has been activated in step _X4 and that the power steering has been activated in step _X6 , the control unit 1
Step 3 executes step _X17 , and calculates the power steering load correction amount D ₁ ' in accordance with the engine speed N indicated by the engine speed signal c. In that case, if the engine rotational speed N does not decrease as markedly as the left because the steering speed, etc. of the steering wheel is small, the power steering load correction amount D ₁ ' is set to be relatively small; When the drop in engine speed is significant, the correction amount D ₁ ' is set to be large. Then, _the control unit ₁₃ adds this power steering load correction amount D ₁ ′ and other load correction amounts D _{1 ″} in step The final control amount Dx is obtained by adding the correction amount _D1 , the basic control amount _D0 , and the feedback control amount _D2 , and then in step _X16 , the final control amount Dx is output to the electromagnetic control valve 11. Even if the steering speed of the steering wheel changes over time after the final control amount _Dx set in The correction amount D ₁ ′ is changed according to the engine speed N at that time.In other words, as shown by the symbol A in FIG. 4, when the engine speed N is high, the power steering load correction amount D ₁ ′ is reduced. , and when the engine speed N is low, the correction amount D ₁ ' will be increased. In this way, the power steering load correction is made according to the level of the engine speed N, that is, the magnitude of the load acting on the engine 1. The amount D ₁ ′ is adjusted, and the final control amount Dx calculated based on this correction amount D ₁ ′ is output to the electromagnetic control valve 11 as the idle control signal b. It is possible to perform stable idle control by preventing a delay in the return of the engine speed and speed-up, etc., which occur when the To prevent a situation in which the engine speed increases due to the above-mentioned power steering load correction amount being too large for the power steering load during low-speed driving at low speeds, and the vehicle jumps out contrary to the driver's expectations. becomes possible.

When the engine 1 is not in the idle region, _{the control unit 13 executes} steps _X2 to _X18 in FIG. Let the control amount Dx be the control amount. In other words, this standby amount D ₃ is set to the idle speed in order to prevent the engine speed from dropping due to a delay in the start of idle speed control when the operating range shifts from outside the idle range to within the range. This is for opening the electromagnetic control valve 11 by an appropriate amount in advance outside the area.

Here, in this embodiment, the power steering load correction amount when the power steering is activated is variably controlled according to the engine speed, but the load on air conditioners, etc. whose load size varies depending on the temperature etc. The correction amount may be variably controlled depending on the engine speed.

Furthermore, in this embodiment, the bypass passage 1
Although the idle speed is controlled by adjusting the flow rate of air passing through the intake passage 5 using the electromagnetic control valve 11, the flow rate of air passing through the intake passage 5 is controlled by the throttle valve 8. Idle control may be performed by this.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the basic concept of the present invention. Figures 2 to 4 show examples of the present invention, with Figure 2 being a control system diagram, Figure 3 being a flowchart showing the operation of the control unit, and Figure 4 being a characteristic diagram of the power steering load correction amount. be. B... Intake air amount adjustment means, C... Engine rotation speed detection means, D... Feedback control means,
E... Load detection means, F... Intake air supply means for load correction, G... Control means, 1... Engine, 1
0... Bypass passage, 11... Solenoid control valve, 13
... Control unit, 13 ₃ ... Load correction section, 13 ₄ ... Load correction control section, 17 ... Load sensor.

Claims (1)

[Claims] 1. A rotation speed detection means for detecting the engine rotation speed, and an intake air amount adjusting means for adjusting the amount of intake air supplied to the engine, the engine rotation speed detected by the rotation speed detection means and a target idle rotation speed. An engine idle speed control device that adjusts the intake air amount by the intake air amount adjusting means based on the deviation from the engine speed and feeds back the engine speed to the target idle speed, and detects the operation of the load. and a load correction intake air supply means for supplying a predetermined amount of intake air to the engine when load operation is detected by the load detection means, and the load correction intake air supply means supplies a predetermined amount of intake air to the engine. 1. A control device for controlling an idle rotation speed of an engine, comprising a control means for adjusting the amount of intake air to be decreased as the engine rotation speed detected by the rotation speed detection means increases.