JPH077565Y2 - Engine idle control device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention supplies auxiliary air to the exhaust port portion or its vicinity while the engine is idling, and matches its rotational speed with the target idle rotational speed. The present invention relates to an idle control device for an engine, which is configured to perform feedback control so as to perform the control.

(Prior Art) In an engine mounted on a vehicle or the like, when the engine is idling, feedback control of the intake air amount, ignition timing, etc. is performed in order to match the engine speed with a target idle speed. Known to have been made known.

Further, when in a low load operation state including the idling state, a part of the air pressurized by the pressurized air supply means such as the supercharger is supplied as auxiliary air to the exhaust port portion or its vicinity, thereby, An engine in which exhaust gas is forcibly discharged to an exhaust passage in which a catalytic converter is arranged is also known as disclosed in, for example, Japanese Patent Laid-Open No. 61-237814. When the engine in which the pressurized air is supplied to the exhaust port portion or its vicinity is a rotary piston engine, for example, as shown in Japanese Utility Model Laid-Open No. 61-190442, Since the amount of exhaust gas carried from the working chamber in which the process is performed to the working chamber in which the intake process is performed is reduced, the effect of improving the combustion stability of the air-fuel mixture is also obtained.

(Problems to be Solved by the Invention) As described above, both feedback control of the intake air amount and ignition timing in the idling operation state and supply of pressurized air to the exhaust port portion or its vicinity are performed. In the engine made to, in the idling operation state, exhaust gas is forcibly discharged from the combustion chamber, and the combustion state in the combustion chamber is improved, so that the exhaust gas purification performance is improved, and The target idle speed set under the feedback control is set to a relatively low value, and the actual idle speed can be lowered without impairing the stability.

However, the engine is configured to perform both feedback control of the intake air amount and ignition timing in the idling operation state and supply of pressurized air to the exhaust port portion or its vicinity in this manner, and the combustion chamber If the combustion state in the engine is improved and the idle speed is reduced, the pressurized air supply unit fails, which causes the pressurized air to flow to the exhaust port or its vicinity. If the situation where the fuel is not supplied is mimicked, the combustion state in the combustion chamber deteriorates in the idling operation state and the amount of unburned matter adhering to the spark plug increases, and as a result, the target for feedback control of the intake air amount and the ignition timing. Due to the fact that the idle speed is assumed to have a relatively low value, engine operation is significantly impaired. There is a fear that serves as a constant.

In view of such a point, in the present invention, in the idling operation state of the engine, the feedback control of the intake air amount and the ignition timing is performed, and the auxiliary air is supplied to the exhaust port portion or its vicinity, It is said that the combustion state in the combustion chamber has been improved and the idle speed has been lowered, and even when an abnormality occurs and auxiliary air is not supplied, the idle speed is lowered. It was made possible to avoid the situation where engine operation became extremely unstable due to
An object is to provide an idle control device for an engine.

(Means for Solving the Problems) In order to achieve the above object, an engine idle control device according to the present invention has a basic configuration as shown in FIG.
When the engine is in a specific operating state including the idling state, auxiliary air supply means for supplying auxiliary air to the exhaust port portion or its vicinity of the engine, abnormality detection means for detecting abnormality of the auxiliary air supply means, and target idle Target idle speed setting means for setting the rotation speed, and control means for performing feedback control to match the rotation speed in the idling state of the engine with the target idle speed, the target idle speed setting means,
When the abnormality detection means detects an abnormality in the auxiliary air supply means, the target idle speed is set to be higher than when the abnormality is not detected in the auxiliary air supply means.

(Operation) According to the engine idle control device of the present invention configured as described above, the auxiliary air is supplied from the auxiliary air supply means to the exhaust port portion or its vicinity when the engine is in the idling operation state. . Thereby,
Exhaust gas is forcibly discharged to the exhaust passage to improve the combustion condition of the engine, so the idle speed in the feedback control that is performed to match the engine speed with the target idle speed is low. Even when the engine is rotated, the operational stability of the engine is ensured.

Further, when an abnormality of the auxiliary air supply means is detected while the engine is in the idling operation state, it is prioritized that the combustion state of the engine is improved rather than the reduction of the idle speed. Thus, the target idle speed is set higher than when the auxiliary air supply means has no abnormality. Therefore, the functional deterioration of the spark plug due to the deterioration of the combustion state in the engine is prevented, and the situation in which the operation of the engine becomes unstable is avoided.

(Embodiment) FIG. 2 shows an example of an engine idle control device according to the present invention together with a main part of a rotary piston engine to which the same is applied.

In FIG. 2, the engine body 10 is a rotor housing.
12 and a pair of side housings 14 arranged on both sides of the rotor housing 12 (one side housing 14 is not shown in the figure). Is a rotor having a substantially triangular cross-section and having an apex seal 18 mounted on the apex thereof slidably contacting the trochoidal inner peripheral surface 12a of the rotor housing 12 while performing a planetary rotational movement about the eccentric shaft 20. 16 are arranged. This rotor
Side seals 22 are attached to both side surface portions of each of 16 along the peripheral edge portions thereof, and a corner seal 23 is arranged between the side seal 22 and the apex seal 18.

Between the surface of the rotor 16 and the inner peripheral surface of the rotor housing 12 and the inner surface of the side housing 14, three working chambers of variable volume, that is, an intake working chamber 26a, a compression working chamber 26b and an exhaust working chamber 26c are formed. Two ignition flags 24A and 24B are arranged along the rotation direction of the rotor 16 in a portion of the rotor housing 12 that forms the compression working chamber 26b.
In addition, the exhaust port 2 is provided in the portion forming the exhaust working chamber 26c.
7 is opened, and the exhaust port 27 communicates with the exhaust passage 25. Then, the intake working chamber 26 in the side housing 14
An intake port 30 opens in a portion forming a, and the intake port 30 communicates with an intake passage 32.

The intake passage 32 has an air cleaner 33,
An air flow meter 34 and a throttle valve 35 that opens and closes the intake passage 32 in conjunction with the accelerator pedal are arranged.
The injection ports of the two fuel injection valves 38A and 38B are
It is supposed to face the portion close to 10 and the portion close to the intake port 30, respectively. In addition, the intake passage 32 is provided with a bypass portion 36 that connects the upstream side portion and the downstream side portion of the throttle valve 35, and the bypass portion 36 is provided with a flow rate adjusting valve 37.

On the other hand, a communication passage 40 is formed near the portion of the rotor housing 12 where the exhaust port 27 is formed. The downstream end 40a of the communication passage 40 forms an annular portion surrounding the exhaust port 27 and is opened to the exhaust working chamber 26c, and the upstream end thereof is provided with a check valve 43. It is also connected to one end of the first pressurized air supply passage 41.
The other end of the first pressurized air supply passage 41 has a second pressurized air in which a diaphragm type opening / closing valve 44 controlled by an electromagnetic switching valve 48 and a pressure pump 46 driven by an engine are arranged. It is connected to a downstream side portion of the supply passage 42, and one end of the second compressed air supply passage 42 has an intake passage 32.
Is connected to the upstream side of the throttle valve 35, and the other end is connected to an air outlet passage 47 in which a diaphragm type on-off valve 45 controlled by an electromagnetic switching valve 48 is arranged. The communication passage 40, the first and second pressurized air supply passages 41 and 42, the check valve 43, the diaphragm type opening / closing valves 44 and 45, the pressurizing pump 46, the air outlet passage 47, and the electromagnetic switching. Pressurized air supply means is constituted by the valve 48 and the like.

The pressurizing pump 46 pressurizes the intake air guided from the intake passage 32 through the upstream side portion of the second pressurized air supply passage 42 and discharges it to the downstream side portion of the second pressurized air supply passage 42. To be done. Further, the opening / closing valve 44 has a valve body 44a and a diaphragm chamber 44b, and is located at a position downstream of the second pressurized air supply passage 42 opposite to the other end of the first pressurized air supply passage 41. The negative pressure is applied to the diaphragm chamber 44b from the portion of the intake passage 32 downstream of the throttle valve 35 through the main negative pressure introduction passage 49, the electromagnetic switching valve 48 and the sub negative pressure introduction passage 49a. When introduced, the valve element 44a is pulled in, whereby the first pressurized air supply passage 41 and the second pressurized air supply passage 42 are brought into communication with each other.

On the other hand, the on-off valve 45 has a valve body 45a and a diaphragm chamber 45b, and is arranged at an upstream side portion of the air outlet passage 47 at a position facing the other end of the second pressurized air supply passage 42. When the negative pressure is introduced into the diaphragm chamber 45b through the main negative pressure introducing passage 49, the electromagnetic switching valve 48 and the sub negative pressure introducing passage 49b, the valve body 45a is pulled in, and thereby the second pressurization is performed. The compressed air supply passage 42 and the air outlet passage 47 are made to communicate with each other.

In addition to such a configuration, a control unit 60 is provided. The control unit 60 includes a detection output signal S corresponding to the opening of the throttle valve 35 obtained from the throttle opening sensor 50.
t, a detection output signal Sn obtained from the rotation speed sensor 51 according to the engine rotation speed, a detection output signal Sw obtained from the water temperature sensor 53 according to the cooling water temperature of the engine, and the second pressurized air supply passage 42 First obtained from the arranged pressure sensor 54
The detection output signal Sp corresponding to the pressure on the discharge side of the pressurizing pump 46 in the pressurized air supply passage 42 is supplied, and other detection output signal Sx necessary for controlling the engine is also supplied.

The control unit 60 is based on the various detection output signals described above,
Pressurized air supply control and idle speed control are performed.

In the pressurized air supply control by the control unit 60, based on the detection output signals St and Sn, the engine is idling in which the throttle valve 35 is in the fully closed state and the rotation speed is below a predetermined value. When it is detected that the engine is in the low load and low rotation operating state including the state, the drive signal Ca is supplied to the electromagnetic switching valve 48. As a result, the main negative pressure introduction passage 49
And the sub-negative pressure introduction passage 49a are in communication with each other,
Atmospheric port 48a and auxiliary negative pressure introduction passage 4 in the electromagnetic switching valve 48
9b is in communication. In such a state, negative pressure is introduced into the diaphragm chamber 44b of the opening / closing valve 44 to draw in the valve element 44a, so that the first pressurized air supply passage 41 and the second pressurized air supply passage 42 are separated from each other. They are in communication,
The valve body 45a of the on-off valve 45 is projected so that the second pressurized air supply passage 42 and the air outlet passage 47 are shut off, and the pressurized air discharged from the pressure pump 46 serves as auxiliary air. It is supplied into the exhaust working chamber 26c through the second pressurized air supply passage 41 and the communication passage 40.

As a result, the exhaust gas in the vicinity of the exhaust port 27 in the exhaust working chamber 26c is forcibly discharged from the exhaust port 27 to the exhaust passage 25 by the pressurized air, so that it is carried from the exhaust working chamber 26c to the intake working chamber 26a. The amount of exhaust gas is reduced,
The combustion state of the air-fuel mixture in the compression working chamber 26b is made good. Therefore, the operational stability of the engine is ensured and the exhaust gas purification performance is improved.

On the other hand, when it is detected that the engine is not in the low load / low speed operation state including the idling state, the solenoid switching valve
The supply of the drive signal Ca to 48 is stopped. As a result, the main negative pressure introducing passage 49 and the sub negative pressure introducing passage 49b are brought into communication with each other, and the atmosphere port in the electromagnetic switching valve 48 is connected.
The communication between 48a and the sub-negative pressure introducing passage 49a is established. In such a state, the valve element 44a of the on-off valve 44 is made to project, the first pressurized air supply passage 41 and the second pressurized air supply passage 42 are shut off, and the on-off valve 45 is opened. A negative pressure is introduced into the diaphragm chamber 45b of the valve body 45a, the valve body 45a is drawn in, the second pressurized air supply passage 42 and the air discharge passage 47 are brought into communication with each other, and the pressure discharged from the pressure pump 46 is increased. Air is discharged to the outside through the air outlet passage 47.

Further, the control unit 60 performs idle speed control when it is detected that the engine is in the idling operation state. In the idle speed control by the control unit 60, the operating state of the engine, for example, the cooling water temperature of the engine represented by the detection output signal Sw or the detection output signal Sx
The target idle speed is set in accordance with the operating state of the auxiliary machinery driven by the engine. At this time, the second pressurized air supply passage represented by the detection output signal Sp
The pressure on the discharge side of the pressure pump 46 at 42 is a predetermined value Pa,
For example, when the value is slightly higher than the atmospheric pressure, it is determined that the pressurized air supply means operates normally and the pressurized air is supplied to the exhaust working chamber 26c, and the target idle speed is It is set to a relatively low value, for example, within a relatively narrow range centered at 500 rpm. On the other hand, when the pressure on the discharge side of the pressurizing pump 46 in the second pressurizing air supply passage 42 is less than the value Pa, the pressurizing air supply means has an abnormality such as a failure of the pressurizing pump 46. When it occurs, it is determined that the pressurized air is not supplied to the exhaust working chamber 26c, and the target idle speed is set to a value within a relatively narrow range centered at 800 rpm, for example.

Further, a reference control value according to the cooling water temperature of the engine, and a load correction value according to the operating state of the auxiliary machinery driven by the engine are set, and further, the target idle speed and the detection output signal Sn are shown. The feedback correction value is set based on the difference from the engine speed. Then, the final control value is calculated by adding the load correction value and the feedback correction value to the reference control value, and the drive pulse signal Cp having the pulse width corresponding to the pulse occupancy rate corresponding to the final control value is formed. , Which is supplied to the flow rate adjusting valve 37.
As a result, the flow rate adjusting valve 37 is opened only for the period corresponding to the pulse width of the drive pulse signal Cp, the intake air amount passing through the bypass section 36 is adjusted, and the actual engine speed matches the target idle speed. It is controlled to be forced.

On the other hand, when the engine is not in the idling operation state, for example, a control value having a constant value is set, and a drive pulse signal Cp having a pulse width corresponding to the pulse occupancy rate corresponding to the control value is formed. To be done. Then, the drive pulse signal Cp is supplied to the flow rate adjusting valve 37, whereby open loop control of the intake air amount is performed.

As described above, when the engine is in the idling operation state, the compressed air supply control is performed in which the compressed air is supplied from the compressed air supply unit to the exhaust working chamber 26c, so that the target idle rotation speed in the idle rotation speed control is controlled. It is possible to set the number to a relatively low value. In addition, in such an idling operation state, when abnormality occurs in the pressurized air supply means and the pressurized air is not supplied to the exhaust working chamber 26c, it is avoided that the combustion state in the compression working chamber 26b deteriorates. Therefore, the target idle speed is set to be higher than that when there is no abnormality in the pressurized air supply means, which causes deterioration of the function of the spark plug due to deterioration of the combustion state in the compression working chamber 26b. This prevents the situation where the operation of the engine becomes unstable.

The control unit 60 that performs the operation control as described above is configured using, for example, a microcomputer.
An example of a program for idle speed control executed by the microcomputer in such a case will be described below.
This will be described with reference to the flowchart in the figure.

In the program shown by the flowchart of FIG. 3, after the start, in step 71, various detection output signals are fetched, and in the following step 72, the engine operates the throttle valve based on the detection output signals St and Sn.
It is determined whether or not 35 is in a fully closed state and the engine speed N is in an idling operation state in which it is equal to or less than a predetermined value. As a result of the determination, when the engine is in the idling operation state, in step 74, the pressure P on the discharge side of the pressurizing pump 46 in the second pressurized air supply passage 42 represented by the detection output signal Sp is the value Pa or more. If the pressure P is equal to or higher than the value Pa, in step 75, the cooling water temperature of the engine represented by the detection output signal Sw and the operation of the auxiliary machinery driven by the engine represented by the detection output signal Sx are performed. Target idle speed TN depending on conditions
i is set to take a value within a relatively narrow range around 500 rpm, and the process proceeds to step 78. Also, step 74
If the pressure P on the discharge side of the pressurizing pump 46 in the second pressurized air supply passage 42 is less than the value Pa, the target idle speed TNi is set to 8 in Step 77.
It is set as a value within a relatively narrow range centered around 00 rpm, and the routine proceeds to step 78.

In step 78, the basic control value GB is set according to the engine cooling water temperature, etc., and in step 79, the load correction value according to the operating state of the auxiliary machinery driven by the engine.
Set the GL. In the following step 80, the engine speed N is subtracted from the target idle speed TNi to calculate the difference ΔNi, and then, in step 81, the feedback correction value GF is set according to the difference ΔNi, and the process proceeds to step 82. In step 82, the final control value GA is calculated by adding the load correction value GLJ feedback correction value GF to the basic control value GB, and in step 83, it corresponds to the pulse occupancy rate according to the final control value GA. A drive pulse signal Cp having a pulse width is formed, and the drive pulse signal Cp is sent to the flow rate adjusting valve 37 and returned to the original state.

On the other hand, as a result of the determination in step 72, when the engine is not in the idling operation state, in step 84, the open loop control program is executed and the process returns to the original.

In the above example, the feedback control on the engine idle speed is performed by changing the intake air amount, but in the engine idle control device according to the present invention, such feedback control is performed. Instead of the intake air amount, another control target in the engine, for example, the ignition timing may be changed.

Further, in the above-mentioned example, the pressurized air obtained from the pressurizing pump 46 is used as auxiliary air, but instead of such a configuration, the intake passage 32 and the exhaust passage 25 are The reed valve may be connected by a communication passage, and unpressurized air obtained through the communication passage may be used as auxiliary air.

(Effect of the Invention) As is clear from the above description, according to the engine idle control device of the present invention, when the engine is in the idling operation state, the auxiliary air is supplied from the auxiliary air supply means to the exhaust port portion or its vicinity. By being supplied, the exhaust gas is forcibly discharged to the exhaust passage and the combustion state of the engine is improved, so feedback control is performed to match the engine speed with the target idle speed. Even when the idle speed is reduced in the engine, it is possible to secure the operation stability of the engine and improve the exhaust gas purification performance.

Further, when an abnormality of the auxiliary air supply means is detected while the engine is in the idling operation state, it is prioritized that the combustion state of the engine is improved rather than the reduction of the idle speed. As a result, the target idle speed is set higher than when the auxiliary air supply means is not abnormal, so that it is possible to prevent the function of the spark plug from deteriorating due to the deterioration of the combustion state in the engine, and to operate the engine. It is possible to avoid the situation where is unstable.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an engine idle control device according to the present invention in correspondence with a utility model registration claim, and FIG.
FIG. 3 is a schematic configuration diagram showing an example of an idle control device according to the present invention together with a rotary piston engine to which the idle control device is applied. FIG. 3 shows a case where a microcomputer is used in the control unit of the example shown in FIG. 3 is a flowchart showing an example of a program executed by such a microcomputer. In the figure, 26a is an intake working chamber, 26b is a compression working chamber, 26c is an exhaust working chamber, 27 is an exhaust port, 32 is an intake passage, 35 is a throttle valve, 36 is a bypass section, 37 is a flow control valve, and 40 is a continuous valve. aisle,
41 is a first pressurized air supply passage, 42 is a second pressurized air supply passage, 44 and 45 are opening / closing valves, 46 is a pressure pump, 47 is an air outlet passage, 48 is an electromagnetic switching valve, 54 is a pressure A sensor, 60 is a control unit.

Claims (1)

[Scope of utility model registration request] 1. When the engine is in a specific operating state including an idling state, auxiliary air supply means for supplying auxiliary air to the exhaust port portion or its vicinity of the engine, and an abnormality of the auxiliary air supply means are detected. Abnormality detection means, and a target idle rotation speed for setting a target idle rotation speed that is increased when abnormality of the auxiliary air supply means is detected by the abnormality detection means as compared with when abnormality of the auxiliary air supply means is not detected. An engine idle control device comprising: setting means; and control means for performing feedback control so that the engine speed in the idling state matches the target idle speed.