JPH0214981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine idle speed control device, and more particularly to an idle speed control device that allows the engine to idle at the most preferable engine speed depending on engine conditions.

Generally, in an automobile engine, the engine rotational speed when the vehicle is stopped, that is, when the engine is in an idling state, is kept as low as possible within the limit that allows a stable operating state to be obtained. However, if this engine speed is set under normal operating conditions, if the engine is at a low temperature such as during a cold start, the atomization or vaporization of the air-fuel mixture may be poor, or the viscosity of the lubricating oil may be high. , stable idling cannot be achieved unless the engine rotational speed is increased to a certain level. For this reason, in conventional engines, when the engine temperature is below a predetermined value, the throttle valve opening of the engine in the idle state is slightly increased to increase the idle speed and enable stable idle operation. Some devices perform idle control.

However, this fast idle control has a problem in that it is not possible to control the idle rotation speed to the most suitable value for the actual temperature of the engine. Additionally, although this fast idle control does not take into account the engine load at all, idling is not necessarily performed under completely no-load conditions, and it is necessary to drive the torque converter of an automatic transmission, drive the air conditioner, etc. It is not uncommon for a load to be added to the engine by driving the engine or turning on lighting equipment, and this load causes fluctuations in the idle speed of the engine. Therefore, maintaining the engine idle speed at a desired value under various load conditions becomes an important issue.

Under such circumstances, a method has been proposed in which electrical feedback control is performed to make the idle speed match a target speed set under certain operating conditions. For example, the idling speed control device disclosed in Utility Model Application Publication No. 55-137234 inputs various conditions such as the use of the air conditioner mentioned above in the form of input information to a calculation device, and the calculation device inputs each input information. The most suitable target idle rotation speed is calculated according to the combination of A pulse having a duty ratio proportional to the difference between the two rotational speeds is outputted, and based on this output, the electric actuation control device controls the diaphragm type negative pressure response means, thereby controlling the opening degree of the engine throttle valve. The idle speed is automatically controlled to a desired idle speed.

However, although it is conceivable that these conventional idling speed control devices provide somewhat satisfactory results under normal conditions, they may cause problems due to load fluctuations caused by shifts in the gear position of the hydraulic automatic transmission during idling operation. Since a feedback control method is adopted in which the control amount changes only when the rotational speed changes, there is a drawback that the deviation from the target idle rotational speed until the rotational speed stabilizes is large and the response is slow.

In order to improve the responsiveness of this idle speed control, in the unloaded speed automatic control method for an internal combustion engine disclosed in JP-A-54-113725, the load change itself is detected and the speed is controlled accordingly. A method is adopted in which changes are predicted and predictive control is added to the feedback control described above.

However, in this automatic control method,
The above predictive control is performed without taking into account the fact that the higher the engine speed, the greater the load on the engine from the torque converter in the hydraulic automatic transmission. If the engine speed is set to a value suitable for a low target, it will be insufficient for the required value when the engine speed is high. Therefore, when shifting the automatic transmission to the drive position as described above, the speed The problem was that the idle speed suddenly dropped temporarily and the idle speed became unstable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel engine idle rotation control device that does not have the above-mentioned drawbacks in idle rotation control when shifting an automatic transmission to a drive position when the engine is in a high-speed rotation state. It is something to do.

The engine idle speed control device according to the present invention includes a rotation detector that detects the engine speed, an actuator that controls control parameters related to increases and decreases in the engine speed in order to adjust the engine speed, and an actuator that controls control parameters related to increases and decreases in the engine speed, and The target idle rotation speed set by the engine is compared with the actual idle rotation speed detected by the rotation detector to detect the difference between the two speeds, and the idle rotation speed is adjusted to the target idle rotation speed based on the difference between the two speeds. A control means outputs a control signal to the actuator in order to drive and control the actuator so as to achieve an idle rotational speed, and a control means outputs a shift signal upon detecting that the shift position of the automatic transmission is shifted from a non-drive position to a drive position. Gear shift detector that occurs,
When the shift signal is received from the speed change detector during idling, a correction means provides a correction signal in the direction of engine speed increase to the actuator, and a speed change of the automatic transmission according to the engine rotation speed detected by the rotation detector. The correction amount adjusting means is configured to adjust the correction signal in the direction of increasing the correction amount in the speed increasing direction when the actual engine is at a high rotation speed when the engine is in the non-drive position.

According to the engine idle rotation control device of the present invention having the above structure, the correction signal given by the correction means to the actuator in the direction of engine speed increase is increased in accordance with the rotation speed of the engine when the engine rotates at high speed. Since the engine rotation speed is adjusted in the direction of increasing it further, even when the transmission shifts from the non-drive position to the drive position, the engine rotation speed does not drop suddenly, thus achieving stable control. The engine can be idled in a desired state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine idle rotation control device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a structural and functional diagram of an idle rotation control device 2 of the present invention incorporated into an engine 1. As shown in FIG.

The engine 1 has a cylinder 3 and a piston 4 fitted into the cylinder 3, like a normal engine, and an intake port 5 and an exhaust port 6 are formed in the upper part of the cylinder 3. The intake port 5 and the exhaust port 6 are provided with an intake valve 7 and an exhaust valve 8 for opening and closing the respective ports.

An intake system 9 and an exhaust system 10 are connected to the intake port 5 and the exhaust port 6, respectively. The intake system 9 includes an intake pipe section 11 and a throttle valve 1.
2 and an intake manifold 13. An air cleaner 14 is provided at the inlet end of the intake pipe section 11, and an air flow sensor 15 for detecting the amount of air flowing through the intake pipe section 11 is arranged downstream of the air cleaner 14. Further, on the upstream side of the throttle valve 12 of the intake pipe section 11, an amount and timing corresponding to the amount of incoming air detected by the air flow sensor 15 and the rotation speed of the engine 1 detected by the engine rotation speed sensor 16 are provided. A fuel injection device 17 for injecting fuel is provided. This fuel injection device 17 is driven and controlled by a microcomputer 18.

A bypass passage 19 is provided in the intake pipe portion 11 to communicate the upstream side and the downstream side of the throttle valve 12. This bypass passage 19 is provided with a flow rate control valve 20 which is opened and closed by a pulse motor, for example, for controlling the flow rate of air or air-fuel mixture flowing through this bypass passage 19 . The opening and closing of this flow rate control valve 20 is controlled by the computer 18. In addition to the inflow air amount information _D1 from the air flow sensor 15 and the actual idle speed information _D2 from the engine speed sensor 16, the computer 18 also detects the closed state of the throttle valve 12 and detects the engine speed. idle operation information D ₃ from the idle detection device 21 that detects the idle operation state of the engine 1, engine temperature information D ₄ from the water temperature sensor 22 that detects the temperature of the engine 1, and non-operation information of the hydraulic automatic transmission (not shown). Engine operating state information such as shift information _D5 from the shift switch 23 which instructs the shift of the gear position from the drive position to the drive position is input.

Next, the operation of the idle rotation control device having the structure described above will be explained with reference to the flowchart shown in FIG. In addition, in the flowchart of Fig. 2, the flowchart symbols attached to the left side ~
is one cycle of control, and control for, for example, one rotation cycle is performed in synchronization with the rotation of the engine.

When the engine is started and the computer 18 is activated, it is first determined whether or not the engine is idling based on the idling operation information _D3 (). Here, if it is determined that the engine is idling, the engine temperature is detected by the water temperature sensor 22 (), and then information
A target idle rotation speed N _set is calculated based on D ₄ ( ), and this target idle rotation speed N _set is stored in the memory of the computer 18 . After this, the actual idle speed N _rpn (according to the information D ₂ ) is detected ( ) and this actual idle speed N _rpn is also input to the computer 18 . The computer 18 uses the central processing unit to calculate the calculated target idle rotation speed.
Using N _set and the detected actual idle rotation speed N _rpn , the formula I = (N _set - N _rpn ) + I I: calculates the integral output value (), and calculates the number of pulses based on the calculated integral output value I. Generate a pulsed control signal _S1 (). This control signal _S1 is for adjusting the opening degree of the flow control valve 20 according to the number of pulses.

Thereafter, the computer 18 receives shift information _D5 from the shift switch 23 and determines whether the transmission is in the non-drive position or in the drive position based on this information _D5 (). When the control signal S 1 is in the non-drive position, the control signal S ₁ is supplied as is to the flow control valve 20, and the control signal S ₁
The flow rate control valve 20 is opened at an opening degree corresponding to the size of the engine, and the air-fuel mixture is caused to flow through the bypass passage 19 to increase the amount of intake air, thereby controlling the normal idle speed. This control mode is shown in solid lines in FIG.

On the other hand, when the transmission is in the drive position, a predetermined amount of correction signal _S2 is generated for a period of time during which the engine speed temporarily falls when shifting to the drive position (). Next, the computer 18 determines, based on the information _D2 from the engine rotation speed sensor 22, whether the engine rotation speed is a predetermined value or more, that is, whether the engine 1 is in a high speed rotation state (). If this judgment is NO, the control signal _is
S ₁ is corrected and increased by the above time (), and the correction signal S ₂ regarding the load is generated by the shift signal to the drive position.
The idle speed is controlled while performing predictive control. The mode of this control is shown by the chain line in FIG. On the other hand, if the determination is YES, increase the correction signal _S2 so that it becomes larger as the engine speed increases (if the magnitude of the correction signal is expressed by the number of pulses, increase the number of pulses). ) generates a correction signal S ₃ (). This correction signal
_S3 is also generated for the above time. Next, the control signal _S1 is corrected and increased by the above-mentioned time using this correction signal _S3 (), and the idle speed is controlled while carrying out anticipatory control using the correction signal _S3 regarding the load due to the shift and the engine speed. This state of control is shown in broken lines in FIG.

By repeating the above steps, control is performed according to various conditions of the idle rotation speed.

Incidentally, FIG. 4 shows this embodiment constructed from an analog circuit. As shown in this figure,
A set voltage generator 30 is connected to the water temperature sensor 22 . This set voltage generator 30 generates a voltage V _set according to the engine temperature information _D4 from the water temperature sensor 22, and this voltage
V _set ′ corresponds to the target idle rotational speed N _set described above. This voltage V _set is input to one input terminal of the comparator 31 .

On the other hand, a rotation speed-voltage transmission 32 is connected to the engine rotation speed sensor 16, and this transmission 32 is configured to generate a voltage proportional to the actual idle rotation speed _Nrpn of the engine detected by the rotation speed sensor 16. Generates voltage _Vrpn . This voltage V _rpn is
1 is input to the other input terminal of 1.

Comparator 31 compares two voltages V _set and V _rpn and outputs an electrical signal proportional to the difference. This electrical signal is input to an integrator 33, which integrates this electrical signal based on the formula I=(N _set −N _rpn ) ₊₉ I: integral output value, and generates a control signal which is a voltage. It outputs _V1 .

The output end of the integrator 33 is connected to the input end of a drive circuit 34 that drives and controls the flow rate control valve 20. The drive circuit 34 receives the control signal V ₁ from the integrator 33 and generates control pulses P with a number of pulses corresponding to the voltage value of the control signal V ₁ . This drive circuit 34 includes an estimated correction circuit 35.
The shift switch 23 and the timer 36 are connected to the estimated correction circuit 35, as well as the engine rotation speed sensor 16.
The correction amount control circuit 37 is connected to the correction amount control circuit 37 . The expected correction circuit 35 is connected to the shift switch 23.
The correction amount control circuit 37 outputs the estimated correction signal S ₄ for a time determined by the timer ₃₆ in accordance with the information D 5 from the engine rotation speed sensor 16 . ₂ , a correction amount control signal _S5 is output in accordance with the degree of high engine speed. When the engine 1 is in a high-speed rotation state, the estimated correction signal S ₄ is increased by the correction amount control signal S ₅ , and the control pulse P to be emitted by the drive circuit 34 is corrected by the increased correction signal S ₄ . do. Next, this estimated-corrected control pulse P is supplied to the flow rate control valve 20, and the flow rate control valve 20 is opened at an opening degree corresponding to the number of pulses of this control pulse P, and the air-fuel mixture is caused to flow through the bypass passage 19. The amount of intake air is increased, thereby controlling the idle rotation speed while performing prospective control according to the load caused by shifting the transmission from the non-drive position to the drive position and the high speed rotation of the engine.

In the embodiments described above, the present invention has been described as being applied to a type in which predictive control is performed by opening and closing a bypass passage arranged in parallel with the intake pipe line. It goes without saying that the present invention can also be applied to systems that perform predictive control by directly operating a diaphragm device or the like.

[Brief explanation of drawings]

FIG. 1 is a functional configuration diagram of an idle rotation control device of the present invention incorporated into an engine, FIG. 2 is a flowchart showing an example of the operation of the idle rotation control device of the present invention, and FIG. FIG. 4, which is a graph showing an example of an aspect of idle rotation control by the idle rotation control device of the present invention, is a block diagram showing an example of an analog circuit in the idle rotation control device of the present invention. DESCRIPTION OF SYMBOLS 1... Engine, 2... Idle rotation control device, 9... Intake system, 16... Engine rotation speed sensor, 17... Fuel injection device, 18... Computer, 19... Bypass passage, 20... Flow rate control Valve, 21... Idle detection device, 22... Water temperature sensor, 23... Shift switch.

Claims (1)

[Claims] 1. A rotation detector that detects the engine rotation speed, an actuator that controls control parameters related to increases and decreases in the engine rotation speed in order to adjust the engine rotation speed, and a target idle rotation speed that is set according to the operating state of the engine. A difference between the two speeds is detected by comparing the actual idle rotation speed detected by the rotation detector, and the actuator is operated so that the idle rotation speed becomes the target idle rotation speed based on the difference between the two speeds. A control means that outputs a control signal to the actuator for drive control; a shift detector that detects that the shift position of the automatic transmission is shifted from a non-drive position to a drive position and generates a shift signal;
When the shift signal is received from the speed change detector during idling, according to the engine rotation speed detected by the correction means and the rotation detector, which provides a correction signal in the direction of increasing engine speed to the actuator,
Idle rotation of the engine, which comprises a correction amount adjusting means that adjusts the correction signal in a direction to increase the correction amount in the direction of speed increase when the actual engine is at high rotation when the shift position of the automatic transmission is in the non-drive position. Control device.