JP2503384B2 - Engine controller - Google Patents

Description

The present invention relates to a control device for an engine during idling.

BACKGROUND ART Conventionally, many engines for automobiles and the like have been proposed in which the output is automatically controlled according to the operating state.

One example is to control the idling speed of the engine to an appropriate value according to the warm-up condition of the engine and the load condition due to the drive of auxiliary equipment such as a cooler compressor. For this reason, the engine speed is normally detected. Then, the detection result is compared with the target rotation speed set according to the warm-up state or load state of the engine, and based on the comparison result, the throttle valve or the throttle valve that bypasses the intake flow rate adjusting means is bypassed. Feedback control of so-called rotation speed is performed in which the opening speed of a throttle bypass valve provided in the intake passage is controlled to control the rotation speed of the engine to the target rotation speed. However, in the feedback control of the rotational speed, a considerable delay occurs after the opening of the throttle valve (slottle bypass valve) is changed until it is reflected in the engine speed. However, there is a drawback that the rotational speed cannot be controlled sufficiently when a transient change occurs in the load condition of the engine.

Therefore, a position sensor is installed in the throttle valve and throttle bypass valve, and the throttle valve opening and throttle bypass opening that give the intake air amount that causes the idle speed depending on the engine warm-up state and load state are set. A so-called position feed, which is set as a target value, compares the output of the position sensor with a target valve opening value, and controls the opening of the throttle valve or throttle bypass valve to the target value according to the comparison result. It is also proposed to control the engine speed by performing back control. JP
No. 55-57638 is equipped with a position sensor that detects the position of the actuator that drives the throttle valve. The output of this sensor is compared with the target opening that is set according to the warm-up state to drive the actuator. What controls the opening of the valve is shown.

However, when performing position feed back control of the throttle valve in this way, the responsiveness of control is prompt, but the amount of intake air that gives the target number of revolutions is not directly measured. When a large number of engines are mass-produced, the intake air flow rate obtained with respect to the throttle opening varies due to manufacturing errors, and it is not always possible to obtain the planned idle speed and the engine stalls easily occur. Or, on the contrary, it may cause runaway or increase in noise.

The present invention has been proposed in view of the above, and is configured such that the flow rate of intake air supplied to the combustion passage of the engine through the passage is controlled to the target intake air flow rate. The intake air flow rate detecting means for detecting the flow rate of all intake air supplied to the combustion chamber of the engine through the control device for the engine and the intake air passage of the engine and the intake air passage of the engine. Idle target intake air flow rate information is provided by providing intake air flow rate adjusting means for adjusting the flow rate of intake air, and decreasing the flow rate as the engine temperature increases in accordance with the engine operating conditions including the engine warm-up state. The target intake air amount information means for setting the intake air amount information, the idle target intake air amount information and the detection information of the intake air flow rate detecting means are compared, and the intake air amount is determined according to the comparison result. First intake flow rate control means for controlling the amount adjusting means, rotation speed detecting means for detecting the rotation speed of the engine, target rotation speed setting means for setting idle target rotation speed information according to the operating state of the engine, The second target for controlling the intake air flow rate adjusting means so that the idle target speed information is compared with the detection information of the speed detecting means and the engine speed approaches the target speed according to the comparison result. Intake flow control means, idle detection means for detecting that the engine is in an idle state, stable state detection means for detecting that the engine is in a stable rotational speed state, detection result of the idle detection means, and the stable state Switching control means for selectively activating the first intake air flow rate control means or the second intake air flow rate control means based on the detection result of the detection means is provided. , When the engine is in the idle state and is in the stable rotational speed state, the switching control means operates the second intake air flow rate control means, and the engine is in the idle state and is not in the stable rotational speed state. The gist of an engine control device is characterized in that the switching control means is sometimes configured to operate the first intake air flow rate control means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the downstream end communicates with a combustion chamber (not shown) of the engine E. A throttle valve 2 is arranged in the intake passage 1, and a shaft 2a of the throttle valve 2 is connected to a throttle lever 3 outside the intake passage 1.

When the accelerator pedal (not shown) is depressed at the end 3a of the throttle lever 3, the throttle valve 2 is rotated in the clockwise direction (opening direction) in FIG. 1 via the throttle lever 3. A wire (not shown) for connecting the wire is connected, and further, a return spring (not shown) for urging the throttle valve 2 in the closing direction is attached to the throttle valve 2 so that the pulling force of the wire is increased. When weakened, the throttle valve 2 is closing.

Further, a fuel injection device 20 and an air flow sensor (Kalman vortex flowmeter) 30 are installed in the upstream intake passage of the throttle valve 2 installed position, and the upstream end of the intake passage 1 is connected to the outside air through an air cleaner 40. Is in communication with.

At this time, the air flow sensor 30 is composed of a Karman vortex flowmeter, which uses ultrasonic waves to determine the number of Karman vortices of the intake air generated on the downstream side of the vortex generation column 32 arranged in the measurement passage 31. The absolute flow rate of the intake air is measured by performing the measurement with this, and this measurement information is input to the control unit 15 described later. Also,
The fuel injection device 20 has a solenoid valve 21 interposed in a fuel passage to which low-pressure fuel is supplied from a fuel pump, and the amount of fuel injected into the intake passage 1 corresponds to the opening time of the solenoid valve 21. Then it is set.

By the way, an actuator 4 is provided which controls the opening degree of the throttle valve 2 by engaging the throttle lever 3 during the engine idle operation.
A DC motor (hereinafter simply referred to as "motor") 5 having a worm 6a on its rotating shaft is provided, and the worm 6a with the motor 5 is meshed with an annular worm wheel 6b.

The worm wheel 6b is integrally provided with a pipe shaft 6c having a female threaded portion 6d. It is attached through.

The tip of the rod 7 is in an idle operating state (the accelerator pedal is not depressed by the driver by the driver) to the end 3a of the throttle lever 3 via the idle switch 9 as an idle detecting means. It comes to contact when it is in the state).

Here, the idle switch 9 is a switch that is turned on (closed) in the engine idle operation state and turned off (open) in other states.

The rod 7 has a long hole 7b formed in it.
A pin (not shown) on the actuator body side is guided to 7b, thereby preventing rotation of the rod 7. As described above, since the tip of the rod 7 is in contact with the end 3a of the throttle lever 3 when the engine E is in the idling state, by rotating the motor 5 in a predetermined direction, the rod 7 is piped through the worm gear. When the shaft 6c is rotated and the rod 7 is projected (moved forward) from the actuator 4, the throttle valve 2 is controlled to open, and the motor 5 is rotated in the reverse direction.
When the rod 7 is retracted (retracted) into the actuator 4, the throttle valve 2 is controlled to be closed by the action of the return spring.

Further, a water temperature sensor 11 for detecting a cooling water temperature as a warm-up temperature of the engine E is provided, and a rotation speed sensor 12 for detecting an engine rotation speed by an ignition pulse is provided.

Furthermore, a vehicle speed sensor 13 for detecting the vehicle speed with a pulse signal having a frequency proportional thereto is provided, and as the vehicle speed sensor 13, a known reed switch is used.

Further, a cooler sensor 14 for detecting the operation / non-operation of a cooler compressor (not shown) driven by the engine E is provided.

Then, it receives the detection signals from the respective sensors 9, 11 to 14, 30 and outputs a motor forward rotation drive signal or a motor reverse rotation drive signal, which is an intake air flow rate control signal, based on these signals.
The control unit (microcomputer) 15 that outputs the fuel flow rate control signal to the solenoid valve 21 is also provided. The control unit 15 is idle when the intake flow rate control signal is output to the motor 5. Set condition I when the idle operation state is detected by the switch 9 (when the idle switch 9 is on) (described later)
Under the condition that the feedback control of the engine speed (idle speed control) is performed by the signal from the speed sensor 12, under the other set condition II (described later) when the idle condition is detected, the air flow sensor 30 The feedback control of the intake air flow rate supplied to the combustion chamber of the engine is performed by the signal from the. That is, the control unit 15 cooperates with the actuator 4 to configure the first and second intake air flow rate control means, and alternatively, the first intake air flow rate control means or the second intake air flow rate control means can be selectively used during idling. It is equipped with a switching control means for operating.

Here, the condition I means that at least the following items are satisfied and the engine is relatively stable.

(1) A predetermined time has elapsed after the idle switch 9 changed from off to on.

(2) The vehicle speed is extremely low (for example, 3 km / h or less).

(3) The deviation of the actual engine speed (actual speed) from the target number of times is within a predetermined range.

(4) The specified time has elapsed after the cooler compressor was switched between active and inactive.

The condition II is a condition when the condition I is not satisfied, the engine is not relatively stable, and quick feedback control is desired.

The intake air amount control during idling by the control unit 15 will be described below with reference to the flow chart of FIG.

As shown in Fig. 2, this control program initializes each register etc. of the microcomputer in A-100, and then processes and discriminates between A-101 to A-117 by timer allocation for each set time. It is executed by default. And first, A-
At 101, operating state information from each of the sensors 9, 11 to 14, 30, that is, idle information Isw from the idle switch 9, cooling water temperature information Tw from the water temperature sensor 11, actual rotation speed information Nr from the rotation speed sensor 12, The vehicle speed information Vr from the vehicle speed sensor 13, the compressor operation information Csw from the cooler sensor 14, and the intake air amount information Qr from the air flow sensor 30 are read into each address of the RAM of the microcomputer, and then in A-102, A-101. The ROM of the microcomputer based on the cooling water temperature information Tw and the compressor operation information Csw read by
The target rotation speed data Ns and the target intake air amount data Qs are input to each address of the RAM from the data map. Here, the target rotation speed data Ns and the target intake air amount data Qs are mapped to the cooling water temperature information Tw and the compressor operation information Csw, respectively, as shown in FIGS. 3 and 4. That is, here, the functions as the target rotation speed setting means and the target intake air amount information setting means are fulfilled. It should be noted that the target intake air amount data Qs shown in FIG. 4 is data that gives the intake air amount at which the idle speed of the engine becomes the target speed substantially according to the cooling water temperature information Tw. This has been determined experimentally. Next, in A-103, it is determined whether the idle switch 9 is on or off. If the idle switch 9 is off, that is, if the access pedal is depressed, this program ends there, and the next timer interrupt occurs. Therefore, when the idle switch 9 is in the idle state, that is, when the idle switch 9 is in the idle state, A-104 is reached. In this A-104, the time after the idle switch 9 is switched from OFF to ON is the first set time T ₁ (for example, 1 (Seconds) or more is determined. Below A-105
Determines whether the vehicle speed is extremely low (for example, 3 km / h or less), and the A-106 sets the second set time T ₂ (for example, ₂ seconds after the cooler compressor is switched on / off). 1
It is determined whether or not more than a second) has elapsed, and the deviation ΔN between the target rotation speed data Ns and the actual rotation speed information Nr is obtained in A-107, and then the deviation amount with respect to the target rotation speed is determined in A-108. It is determined whether or not it is within the range α (for example, 30%), and as a result of the determination of all stable states of these A-104, A-105, A-106 and A-108, the engine is in a stable state. When the idle switch 9 is turned on, T ₁ hour or more has passed since the idle switch 9 was turned on, the vehicle speed was extremely low, and the cooler compressor was switched between operating and non-operating. ₂
The program reaches A-109 in order to perform the feed back control of the engine speed when the time deviation has passed and the speed deviation ΔN is within the predetermined range α with respect to the target speed. If any one of A-104, A-105, A-106, A-108 is NO, the program is to control the intake air flow rate feedback control.
It has reached to A-113. In the A-109, the third set time T ₃ (for example, 1 second) after the output counter (down counter) that outputs the drive pulse to the motor 5 becomes 0
It is determined whether or not the above has passed. That is, here, the output counter becomes 0 and the motor 5 is stopped after the motor 5 is stopped.
If the drive prohibition time is set and T ₃ hours or more have not passed since the last drive of the motor 5, the program ends as it is. On the other hand, if T ₃ hours or more has passed, A-110 is set. The output pulse width data Dn corresponding to the maximum rotation speed deviation ΔN is read from the ROM and input to a predetermined register. The output pulse width data Dn is mapped to the rotation speed deviation ΔN and stored in the ROM as shown in FIG. Then, in A-111, this pulse width data Dn is set in the output counter for driving the motor 5, and A-1
At 12 it triggers this output counter. As a result, the output counter of the motor 5 is triggered and then the counter becomes 0.
Will be driven until. At this time, A-1
When the deviation ΔN obtained in 07 is positive, that is, when the actual rotation speed is smaller than the target rotation speed, the control unit 15 rotates the motor 5 in the forward direction so that the rod 7 moves forward and the throttle valve 2 is controlled to the open side. When the drive signal is supplied and the deviation .DELTA.N is negative, that is, when the actual rotation speed is higher than the target rotation speed, the control unit 15 controls the motor so that the rod 7 is retracted and the throttle valve 2 is controlled to the closing side. A reverse rotation drive signal is supplied to 5. On the other hand, A-104, A-
If NO is determined by any one of 105, A-106, and A-108, and the program reaches A-113, the fourth set time after the output counter becomes 0. T ₄ (eg
(0.2 seconds) or more is determined. At this time, the motor 5 drive prohibition time T _{4 in} the case of the feed back control of the intake air flow rate is set shorter than the motor 5 drive prohibition time T ₃ in the case of the engine speed feed back control described above. The control is based on the fact that the feedback system has less delay and the system is more stable.
And when the elapsed as program finishes, the other T ₄ hours or more in the case where it is determined that the driving of the last motor 5 in A-113 has not elapsed T ₄ or more hours from the completion A- At 114, the deviation ΔQ between the target intake air amount data Qs and the actual intake air amount information Qr is obtained, and the output pulse width data Dq corresponding to this intake air amount deviation ΔQ is read out from the ROM at A-115. Input to the register. The output pulse width data Dq is mapped to the intake air amount deviation ΔQ and stored in the ROM as shown in FIG. Then, in A-116, this pulse width data Dq is set in the above-mentioned output counter for driving the motor 5, and in A-117, this output counter is triggered. As a result, the motor 5 is driven from when the output counter is triggered until the counter becomes zero. At this time, if the deviation ΔQ obtained in A-114 is positive, that is, if the actual intake air amount is less than the target intake air amount,
The control unit 15 supplies the forward rotation drive signal to the motor 5 to control the throttle valve 2 to the open side, while the deviation ΔQ
When is negative, that is, when the actual intake air amount is larger than the target intake air amount, the control unit 15 supplies a reverse drive signal to the motor to control the throttle valve 2 to the closing side.

Further, the fuel flow rate control signal output from the control unit 15 forms a basic signal based on the intake air amount information detected by the air flow sensor 30, and a correction value is added to this basic signal by other operating state information. Things are supplied to the solenoid valve 21.

According to the above-mentioned configuration, immediately after the driver releases his / her foot from the accelerator pedal (mainly after leaving the vehicle empty), or when the cooler compressor is switched between active and inactive during idle operation, immediately after that switching, Alternatively, when the driver releases his / her foot from the accelerator pedal and the vehicle speed is high, that is, engine braking is normally performed, and it is highly possible that the crankshaft of the engine is connected to the wheels via the power transmission system. When the engine speed is unstable or greatly deviates from the target speed even during idle operation, such as in the case such as when there is a high possibility, the intake air amount is controlled by the feedback control of the intake air amount. Is controlled to the target value, the idle speed quickly and stably approaches the target speed, and thereafter, the feed back control of the engine speed causes Idle speed is obtained and indeed target.

Therefore, it is possible to prevent the idle speed from temporarily increasing to give an occupant an uncomfortable feeling when an engine stall is generated at the time of idling or when the compressor is switched from operating to non-operating. It is the one that can get the virility.

Further, since the actual intake air amount detected by the air flow sensor 30 is configured to be feedback-controlled, when a large number of engines with the same specifications are produced, each engine will rotate at substantially the same engine speed under the same idle operation condition. The number is obtained, and each engine is capable of stable idle operation without the occurrence of stalls.

Further, in the above embodiment, the Karman vortex flowmeter is used to measure the absolute flow rate of the intake air, so the intake air amount information Qr based on this measurement result is the zero point correction when obtaining the intake flow rate control signal. It is possible to compare with the target intake air amount data without performing the above, and the configuration of the entire device is simplified.

Furthermore, in the above embodiment, the throttle valve 2 connected to the accelerator pedal is used as the intake flow rate adjusting means, but the intake flow rate adjusting means is disclosed in JP 54-27624A or JP 54-76723. It may be configured by an air control valve (idle control valve) provided in a bypass passage that bypasses the throttle valve as shown in Japanese Patent Laid-Open Publication No. 1994-13827 and conducts intake air to the combustion chamber.

Further, in the above embodiment, the water temperature sensor 11 for detecting the cooling water temperature as the warm-up temperature of the engine E is shown, but the warm-up temperature is detected by the oil temperature for detecting the lubricating oil temperature of the engine. A sensor may be provided.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the action, and FIGS. 3 to 6 are graphs for explaining the action. 1 ... Intake passage, 2 ... Slot valve, 4 ... Actuator, 9 ... Idle switch, 11 ... Water temperature sensor, 12 ... Rotation speed sensor, 13 ... Vehicle speed sensor, 14 ... Cooler sensor, 15
...... Control unit, 30 ...... Air flow sensor

Claims (1)

(57) [Claims] An intake air flow rate detecting means for detecting a flow rate of all intake air supplied to a combustion chamber of the engine through an intake passage of the engine and an intake air flow rate passing through the intake passage. A target intake air amount information setting for setting the idle target intake air amount information such that the intake air flow rate adjusting means is provided and the flow amount becomes smaller as the engine temperature becomes higher according to the operating state of the engine including the engine warm-up state. Means, first intake air flow rate control means for comparing the idle target intake air amount information and detection information of the intake air flow rate detection means, and controlling the intake air flow rate adjusting means according to the comparison result, the engine speed Rotational speed detection means for detecting the engine speed, target rotational speed setting means for setting idle target rotational speed information according to the operating state of the engine, idle target rotational speed information Second intake flow rate control means for controlling the intake flow rate adjusting means so that the engine speed approaches the idle target speed according to a result of the comparison. An idle detection means for detecting that the engine is in an idle state,
The stable state detecting means for detecting that the engine is in a stable rotational speed state, the detection result of the idle detecting means, and the stable state detecting means based on the detection result of the stable state detecting means.
Of the intake air flow rate control means or the second intake air flow rate control means is selectively operated, and when the engine is in an idle state and in a stable rotational speed state, the switch control means is the first No. 2 intake air flow rate control means is operated, and when the engine is in an idle state and is not in a stable rotation speed state, the switching control means is configured to operate the first intake air flow rate control means. An engine control device characterized by: