JPH0435616B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine idle rotation control device, and more particularly to an idle rotation control device that allows an engine to idle at the most preferable rotation speed depending on engine load 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 these conventional idling speed control devices may give somewhat satisfactory results under normal conditions, when the control system fails, for example, the electrically operated control device that controls the operation of the throttle valve fails. When this occurs, the idle speed may be controlled excessively or insufficiently, and the idle speed may become too high or too low. Such excessive idle speed not only causes discomfort to the driver, but also
In a vehicle equipped with an automatic transmission, a dangerous situation such as an unexpected start of the vehicle may occur, while an excessively low idle speed may cause an inconvenience such as the engine stopping.

SUMMARY OF THE INVENTION Therefore, the present invention provides an idle speed control device that feedback-controls the engine's idle speed to a target value so that the idle speed does not go into an abnormal state even when the control system fails as described above. The object of the present invention is to provide an engine idle rotation control device that can control the idle rotation of an engine.

The engine idle speed control device according to the present invention uses an abnormality detection device to detect a state in which the actual idle speed does not match the target idle speed for a predetermined period of time or more, that is, an abnormality;
The auxiliary actuator, which controls the inflow control valve independently from the main actuator, is driven and controlled based on abnormality detection by the abnormality detection device to set the intake air amount to a predetermined value, thereby reducing the idle rotation speed. It is characterized by performing correction. As the main actuator, for example, a diaphragm type actuator can be used, and as the auxiliary actuator, for example, a solenoid type actuator can be used.

According to the engine idle rotation control device of the present invention, when the idle rotation becomes abnormal, the abnormality is detected by the abnormality detection device, and based on this detection, the auxiliary actuator adjusts, for example, the throttle valve opening. is set at a predetermined position to maintain the intake air amount at a predetermined value, so even if the control system etc. malfunctions, the idle speed will be maintained within the predetermined range and the engine will idle under favorable conditions. rotation can be performed. Furthermore, in the present invention, the abnormal signal for operating the auxiliary actuator is generated by detecting that the actual idle rotation speed does not match the target idle rotation speed for a predetermined period or more. Compared to a case where an abnormal signal is generated every time a state in which the rotation speed and the target idle rotation speed do not match, hunting does not occur and control stability can be obtained. If the actual idle rotation speed does not match the target idle rotation speed for a predetermined period of time or more, there is a risk that the engine will stop or run rough, but in the present invention, such conditions that cause problems in engine operation can be avoided. When this occurs, an abnormality signal is generated and the auxiliary actuator is driven, making it possible to avoid engine stoppage or the like.

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

As is clear from FIG. 1, the intake system of the carburetor engine 1 consists of an intake pipe section 2, a throttle valve 3, and an intake manifold 4. The throttle valve 3 is a lever 3a provided integrally with this valve 3.
The opening is controlled by a diaphragm actuator 5, which is part of an idle rotation control device, to set the opening degree during idle operation.

The actuator 5 is a diaphragm actuator having a diaphragm 6 and a pressure-operated chamber 7 defined by the diaphragm 6. When the pressure in the pressure working chamber 7 becomes low, the diaphragm 6 moves to the left in the figure, thereby causing the connecting rod 8 fixed to the diaphragm 6 to move to the left in the figure.
The throttle valve 3 is slightly opened via the . In addition, at the tip of this connecting rod 8, when this connecting rod moves to the left together with the diaphragm 6,
A hook 8a is provided so that the throttle valve 3 can be rotated clockwise (opening direction) in the figure by acting on the lever 8a.

The pressure working chamber 7 is communicated with the upstream side of the throttle valve 3 of the intake pipe section 2 through an atmospheric pipe line 9, and is communicated with the downstream side of the throttle valve 3 of the intake pipe section 2 via a negative pressure pipe line 10. is communicated with. A first solenoid valve 11 which is a normally open valve is disposed in the atmosphere pipe 9, and a second solenoid valve 12 which is a normally closed valve is disposed in the negative pressure pipe 10. Therefore, in the normal state, the pressure operating chamber 7 is maintained at atmospheric pressure, and the actuator 5 is configured to set the throttle valve 3 at the minimum opening corresponding to normal idling operation.

The first and second solenoid valves 11 and 12 are controlled so that when one is in an operating region, the other is in a non-operating region, and this control is performed by a microcomputer 13. The microcomputer 13 includes, for example, idle operation information D1 from an idle detection device 14 that detects the closed state of the throttle valve 3 to detect the idle operation state of the engine, and engine temperature information from a water temperature sensor 15 that detects the engine temperature. Information D2, air conditioner ON from air conditioner drive switch 16
Engine operating state information such as OFF information D3 and actual idle rotation speed information D4 from the rotation detector 17 that detects the engine rotation speed is input.

Even with the configuration described above, it is possible to perform idle rotation control to some extent, but in this configuration, normal control of the idle rotation speed may not be performed due to a failure in the control system, etc., as described above. Therefore, the idle rotation control device of the present invention includes a control correction device 20 as shown below.
This control correction device 20 is shown in an enlarged scale in FIG.
This control correction device 20 is also shown in FIG. 1, but for convenience of drawing, the structure of the device 20 shown in this drawing is somewhat different from the structure of the device 20 shown in FIG. 2, but the functions are the same. .

The control correction device 20 includes first and second auxiliary actuators 21 and 22 disposed on both sides of the lever 3a. Either one of the first and second auxiliary actuators 21, 22 may be installed depending on the purpose. The first and second auxiliary actuators 21 and 22 are turned on by the computer 13.
- It has first and second armatures 21a and 22a that can take either of two positions, an extended position and a retracted position, by OFF control. These auxiliary actuators 21, 22
When the armatures 21a and 22a are in the extended position, the lever 3a is pressed to maintain the throttle valve 3 at a predetermined opening. The first auxiliary actuator 21 acts in the direction of opening the throttle valve 3, while the second auxiliary actuator 22 acts in the direction of closing the throttle valve 3.

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. 3, the flowchart symbols attached to the left side ~
is one cycle of control, and control is performed for one cycle per revolution in synchronization with the rotation of the engine.

The engine starts and the microcomputer 13
When activated, it is first determined whether or not the vehicle is idling based on the idling operation information D1. Here, if it is determined that the operation is idling, the operating status such as engine temperature and cooler operating status is detected,
Next, a target idle rotation speed Nset is calculated based on the information D2, D3, etc., and this target idle rotation speed Nset is stored in the memory m of the microcomputer 13.
is memorized. After this, the actual idle speed
Nrpm (according to information D4) is detected, and this actual idle rotation speed Nrpm is also input to the computer 13. The computer 13 is a central processing unit
Target idle speed calculated by CPU
Nset and the detected actual idle rotation speed Nrpm are compared and calculated, and a pulse-like correction signal having a duty ratio corresponding to the difference between these two rotation speeds is generated. This operation is performed by the formula I=(Nset-Nrpm)+I. Here, I is an integral output value. This correction signal is a close signal S1 supplied to the first solenoid valve 11 to close the first solenoid valve 11 on the atmosphere side, and a close signal S1 supplied to the second solenoid valve 12 to open the second solenoid valve 12 on the negative pressure side. It consists of an open signal S2.

The first and second solenoid valves 11 and 12 are controlled by the close signal and the open signal S1 and S2, which are pulse signals with a duty ratio proportional to the amount of rotation speed to be corrected, as described above,
Therefore, the air in the pressure working chamber 7 is sucked in proportion to the amount of rotational speed to be corrected. The diaphragm 6 moves to the left with a stroke corresponding to this suction amount, and the connecting rod 8 moves to the left accordingly, and as a result, the throttle valve 3 opens to an opening corresponding to the amount of rotation speed to be corrected. only opened.

As described above, control is performed according to various conditions of the idle rotation speed.

However, as described above, there is a risk that the idle rotation may become abnormal due to a failure in the control system or the like.

Therefore, the microcomputer 13 determines whether or not the corrected actual idle speed Nrpm has reached the target idle speed Nset.
When this determination is NO, it is determined whether this state has continued for a predetermined period of time or more. Then, the above judgment is
When YES, it is determined whether Nrpm<Nset or Nrpm>Nset, and when Nrpm<Nset, the first abnormal signal S3 is supplied to the first auxiliary actuator 21.
and a second abnormality signal S4 to be supplied to the second auxiliary actuator 22 when Nrpm>Nset.
occurs. As a result, when Nrpm<Nset, the first auxiliary actuator 21 is operated to rotate the throttle valve 3 in the opening direction until it reaches a predetermined opening degree, while when Nrpm>Nset, the second auxiliary armature 22 is operated. The throttle valve 3 is rotated in the closing direction until it reaches the predetermined opening degree. The idle speed of the engine is corrected in the manner described above.

Note that the first or second auxiliary actuator 2
1 and 22 are activated, the operation of the control system may be stopped and the throttle valve 3 may be held at the predetermined fixed position.

FIG. 5 is a functional configuration diagram showing the main parts of a bypass type idle rotation control device according to an embodiment of the present invention. In the members and elements shown in Fig. 5, the first
Components having the same functions as those shown in FIG.

Main and sub atmospheric ports 30 and 31 are formed on the upstream side of the throttle valve 3 of the intake pipe section 2, and main and sub negative pressure ports 32 and 33 are formed on the downstream side, respectively. The main atmospheric port 30 and the main negative pressure port 32 are communicated with each other through a control pipe 34, and the control pipe 3
A solenoid control valve 35 to adjust the amount of air flowing through the
is installed. On the other hand, the sub-atmosphere port 31 and the sub-negative pressure port 33 are communicated through a correction pipe 36, and a normally closed electromagnetic correction valve 37 is provided in the middle of the correction pipe 36 to open and close the correction pipe 36. is installed. The control valve 35 and the correction valve 37 each consist of valve bodies 35a, 37a and actuators 35b, 37b that actuate the valve bodies.

Next, the operation of the above-mentioned idle rotation control device will be explained.

The microcomputer 13 compares and calculates the target idle rotation speed Nset calculated based on the engine temperature information D2 and the air conditioner ON/OFF information D3 and the actual idle rotation speed Nrpm, and generates a control signal.
Generate S _c . This calculation is performed by the formula I=(Nset-Nrpm)+I as in the above embodiment.

This control signal _SC is supplied to the electromagnetic control valve 35, and the opening degree of the electromagnetic control valve 35 is determined according to this control signal _SC . In this way, the amount of intake air is controlled depending on the amount of rotational speed to be controlled.

However, due to a failure of the control valve 35 system,
This control valve 35 may remain closed, or may not open sufficiently even if it opens.

Therefore, the microcomputer 13 compares the target idle rotation speed Nset with the actual idle rotation speed Nrpm after a predetermined period of time after control, and issues a correction signal S _A when Nrpm does not reach Nset, that is, in the case of an abnormal state. Program it. This correction signal S _A is supplied to the correction valve 37, and the correction valve 37 opens when this correction signal S _A is supplied.
It is designed to adjust the amount of incoming air.

Furthermore, if the microcomputer 13 is configured to emit an alarm signal such as sound or light when it detects the above-mentioned abnormal condition, the driver can be informed of a failure in the control system, etc., and based on this, the control system It will be possible to carry out repairs at an early stage.

[Brief explanation of drawings]

FIG. 1 is a structural functional diagram of an engine idle speed control device of the present invention incorporated into a carburetor engine, and FIG. 2 is an enlarged view showing the main parts of the idle speed control device shown in FIG. 1. Figure 3 is
FIG. 4 is a flowchart showing an example of the operation of the idle rotation control device of the present invention, and is a functional diagram of the bypass type idle rotation control device for an engine according to the present invention. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake pipe section, 3... Throttle valve, 5... Actuator, 6... Diaphragm, 7... Pressure operation chamber, 9... Atmospheric pipe line, 1
0... Negative pressure pipe line, 11, 12... First and second electromagnetic valves, 13... Microcomputer, 20... Control correction device, 21, 22... First and second auxiliary actuator.

Claims (1)

[Scope of Claims] 1. A rotation detector for detecting the engine rotation speed, a flow rate control means for controlling the amount of intake air supplied to the engine in order to adjust the engine rotation speed during idling, and driving the flow rate control means. The target idle rotation speed set according to the operating state of the actuator to be controlled and the engine is compared with the actual idle rotation speed detected by the rotation detector to detect the difference between the two speeds. In the engine idle rotation control device, the engine idle rotation control device includes an actuator control means for driving and controlling the flow rate control means by causing the actuator to drive and control the flow rate control means so that the idle rotation speed becomes the target idle rotation speed based on the difference, an auxiliary actuator that drives and controls the flow rate control means, an abnormality detection means that detects that the actual idle rotation speed does not match the target idle rotation speed for a predetermined period or more and generates an abnormal signal; An engine idle comprising: a correction means for driving and controlling the auxiliary actuator based on an abnormal signal from the detection means to correct the amount of air flowing into the flow rate control means in accordance with a signal from the actuator control means. Rotation control device. 2. The engine idle rotation control device according to claim 1, wherein the flow rate control means is a throttle valve provided in an intake pipe. 3. The flow rate control means includes main and auxiliary bypass lines that bypass the throttle valve, and main and auxiliary control valves provided in the two bypass lines, respectively, and the actuator drives the main control valve. 2. The engine idle rotation control device according to claim 1, wherein the auxiliary actuator drives and controls the auxiliary control valve.