JPH0154526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the idle speed of an internal combustion engine.

For example, in an internal combustion engine equipped with an auxiliary device such as a cooler, if the cooler operates while the engine is idling, the idle rotational speed will fluctuate, which may cause instability or engine stall. Even when the engine is cold, the same phenomenon as described above tends to occur due to friction loss in each moving part.

Therefore, when an auxiliary device such as a cooler is activated, or when the engine is cold and the cooling water temperature is below a predetermined value, the engine idle rotational speed is increased to eliminate the above-mentioned inconvenience.

Such a conventional example is shown in FIG.

FIG. 1 shows an idle rotation control device for a diesel engine.

A stopper 5, which is the output end of a pressure-responsive actuator 4, is locked to the tip of a swing arm 3 connected to a control lever 2 of a fuel injection pump 1. Specifically, the actuator 4 is composed of a diaphragm, a stopper 5 connected to the diaphragm, and a pressure-operated chamber formed on one side of the diaphragm. Through contact with the swing arm 3, the lower limit value of the fuel injection amount of the control lever 2 is regulated. In the pressure working chamber of the actuator 4,
A controlled negative pressure obtained by controlling the negative pressure value generated by the negative pressure generator 6 to be diluted with the atmosphere by a solenoid valve 7 is introduced via a negative pressure passage 8 . The solenoid valve 7 has an atmosphere release port 9 for releasing the negative pressure in the negative pressure passage 8 to the atmosphere, and when energized, the atmosphere release port 9 is closed and the negative pressure passage 8 is opened and communicated. The excitation circuit of the solenoid valve 7 includes a series circuit of an ignition switch (IG), a water temperature switch 11 that turns on when the engine cooling water temperature is below a predetermined value, a key switch (ACC switch), and a cooler switch 1.
It consists of a series circuit with 2. Cooler switch 12
When turned on, the cooler compressor 13 connected in series to the cooler operates and the cooler indicator lamp 14 lights up.

Therefore, when both the key switch (ACC) and the ignition switch (IG) are turned on and the cooler switch 12 is turned on, the cooler compressor 13 is activated to cool the interior of the vehicle. Since the cooler compressor 13 is driven by the engine output, it is naturally necessary to increase the idle rotational speed of the engine to increase the output. At this time, at the same time as the cooler switch 12 is turned on, the electromagnetic valve 7 is energized and the negative pressure of the negative pressure generator 6 is supplied to the negative pressure working chamber of the actuator 4 via the negative pressure passage 8. Therefore, the diaphragm of the actuator 4 is displaced, causing the stopper 5 to move to the left in the figure, and the tip of the swing arm 3, which is locked to this, swings to the left in the figure, thereby rotating the control lever 2 in the fuel increasing direction. This increases the idle rotation speed. As a result, the engine idle rotation can be stabilized, and at the same time, the cooler can be properly operated, thereby stably and rapidly cooling the room. Similarly, when the engine cooling water temperature is below a predetermined value, the water temperature switch 11 senses this and energizes the solenoid valve 7, increasing the idle rotation speed, causing engine damage caused by low cooling water temperature. It is possible to smoothly idle the engine against the motion frictional resistance of each part and to promote warm-up.

If the cooling water temperature is above a predetermined value and the cooler switch is turned off, the solenoid valve 7 is demagnetized, and the atmosphere is introduced into the negative pressure passage 8 from the atmosphere release port 9, so that the atmosphere is introduced into the negative pressure operating chamber of the actuator 4. , the stopper 5 moves to the right in the figure and the control lever 2
Rotate in the direction of fuel reduction to allow normal idle rotation. (Nissan Motor Co., Ltd.: Service Bulletin No. 382, issued in June 1978, “New Nissan Seedrick,
According to this conventional configuration, as shown in Figure 2, the engine is accelerated from idling by operating the accelerator pedal, and after running at a constant speed, when the accelerator pedal is released and decelerated, the engine is activated. The control lever 2 linked to the accelerator pedal is rapidly displaced in the direction of fuel reduction. At this time, in a transient state in which the engine speed shifts from a deceleration state to an idling state, a so-called overshoot phenomenon occurs in which the engine speed once drops to a lower speed than the idling speed and then returns to a steady idling state. Ta. This is for the following reasons. That is, the stopper 5, which is the output end of the actuator, regulates the idle rotation position of the control lever 2 through engagement with the swing arm 3. When the control lever 2 is rotated in the fuel increasing direction, the swing arm 3 moves away from the stopper 5 and moves to the left in the figure, but due to the sudden deceleration caused by the release of the accelerator pedal, the tip of the swing arm Then it suddenly returns to the right and comes into contact with the stopper 5. At this time, the stopper 5 cannot maintain its abutting position, and the diaphragm connected to the stopper 5 is elastically displaced, causing the stopper 5 to move to the right in the figure, and overshoot itself in the direction of fuel reduction. . Therefore, the driver is inconvenienced in that the overshoot causes discomfort in drivability, or misfires occur due to an insufficient amount of fuel, resulting in poor exhaust emissions.

The present invention aims to solve the above-mentioned problems in the conventional idle rotation control device, and the present invention aims to solve the above-mentioned problems with the conventional idle rotation control device. In addition, in operating ranges other than idle rotation, the stopper position, which is the output end of the actuator, is shifted to the fuel increase side position, and the response delay of the pressure-responsive actuator is used to control the fuel control member by its damper action. It is designed to buffer the overshoot phenomenon during transient operation from deceleration to engine idling, and its specific configuration includes a pressure-responsive actuator that controls engine idling rotation, and a pressure-responsive actuator that controls the pressure of the pressure source by diluting it. a solenoid valve that obtains control pressure to be input to the actuator; an engine load sensor; an operating state detecting device during engine idling; and an idling operating state when idle operating is detected by inputting detection signals from the sensor and the detecting device. Accordingly, the stopper position is changed via the solenoid valve, thereby controlling the engine idle rotation to a predetermined value, and in other operating ranges, the stopper position is set to the fuel increase side than the engine idle rotation of the predetermined value. and a control position for controlling the operation of the electromagnetic valve so as to shift the solenoid valve so that the stopper comes into contact with the fuel control member to provide a buffer before the stopper reaches the target idle position during a transient deceleration of the engine.

Embodiments of the present invention will be described based on the drawings from FIG. 3 onwards.

FIG. 3 shows an embodiment of the present invention, including a control lever 2 as a fuel control member of a fuel injection pump 1, a pressure-responsive actuator 4 for engine idle rotation control, a negative pressure generator 6, a negative pressure passage 8, etc. is the same as the conventional example shown in FIG. The solenoid valve 21 installed in the negative pressure passage 8 has its atmosphere release port 9 communicating with an air cleaner of the engine (not shown), and its configuration is simply a two-position ON/OFF switch based on a switch action as shown in FIG. It is not an on-off valve that selects the desired frequency, but is a type of electromagnetic valve that opens and closes continuously at an appropriate frequency and whose opening/closing time ratio is controlled by a control device 22 such as a microcomputer.

The control device 22 consists of an input/output device (interface), a storage device (memory), and a central processing unit (CPU), and the input/output devices include an ignition switch on/off signal S ₁ , a crank angle sensor, or An engine rotational speed signal S ₂ from a rotation sensor 24 that detects the engine rotational speed consisting of an ignition timing sensor, an auxiliary equipment operation signal S ₃ from an auxiliary equipment switch 25 that detects the operating state of auxiliary equipment such as a cooler and a torque converter, and an accelerator. An accelerator opening signal S ₄ from an accelerator sensor 26 that detects the pedal depression angle and a water temperature signal S ₅ from a water temperature sensor 23 that detects the engine cooling water temperature are respectively input. Here, the accelerator sensor 26 acts on the control lever 2 of the fuel injection pump 1 to control the fuel injection amount, and functions as a load sensor. In addition to this, the load sensor also measures the opening of control lever 2,
It may also be configured to detect the amount of displacement of the fuel control member. The accelerator sensor 26 detects that the engine is idling by detecting the idling position of the accelerator pedal. Auxiliary switch 25 and water temperature sensor 23
functions as a sensor that detects the operating state when the engine is idling.

The control device 22 to which these signals S ₁ to _{S 5} are input is subjected to arithmetic processing by the central processing unit so as to obtain the target value stored in advance in the memory.
A pulse signal S ₀ is output to the solenoid valve 21 .

Looking at the operation of the control device 22 in FIG. 4, the accelerator opening signal _S4 from the accelerator sensor 26 is input to the discriminator 31, and the discriminator 31 determines whether the accelerator opening is the opening when the engine is idling. Determine whether or not. When the engine is idling, the auxiliary equipment operation signal S ₃ is sent from the auxiliary equipment switch 25, and the water temperature signal S ₅ is sent from the water temperature sensor 23.
The target idle rotational speed is calculated based on the input, and compared with the rotational speed signal _S2 from the engine rotation sensor 24, a pulse signal _S0 is sent to the solenoid valve 21 in order to adjust its opening/closing time ratio (duty). Output. When the supplementary air is in operation or when the engine cooling water temperature is below a predetermined value, the target idle rotation speed is increased, the opening time ratio of the solenoid valve 21 is increased (the duty value is increased), and the actuator 4 by increasing the control negative pressure signal input to the swing arm 3.
The control lever 2 is rotated to the fuel increase side via the control lever 2 to increase the fuel injection amount and increase the idling rotational speed. The control characteristics are shown in FIGS. 5 to 7.

On the other hand, if the discriminator 31 determines that the engine is in a state other than idling,
A pulse signal with a duty value increased to a value that apparently increases the rotation speed above the target idle rotation speed is output to the solenoid valve 21. A flowchart of such control is shown in FIG.

Therefore, according to the above configuration, when the engine is in idle operation, the lower the operating state, that is, the lower the cooling water temperature, the higher the engine rotational speed is increased, or the auxiliary equipment is activated, as shown in FIG. In this case, the engine rotation speed is also increased. The control characteristic is determined by the pulse signal S ₀ output from the control device 22.
By controlling the duty value of the negative pressure passage 8, the control negative pressure signal in the negative pressure passage 8 is diluted by the atmospheric dilution effect of the solenoid valve 21, and the control signal is input to the actuator 4, and the stopper 5 moves the swing arm. The control lever 2 is rotated and adjusted via the control lever 3 to increase or decrease the fuel injection device during idling to obtain the engine rotational speed as shown in FIG.

Furthermore, when the discriminator 31 detects a state other than idling rotation, for example, referring to FIG. 9, the engine rotation accelerates from point A to point B by depressing the accelerator pedal, and then runs at a constant speed until point C. After that, if the accelerator pedal is released and the vehicle is decelerated, and the vehicle returns to the idling state, the accelerator pedal depression is directly transmitted to the control lever 22 via a link mechanism, and the control lever 22 is rotated toward the fuel increase side. The engine responsively increases its rotational speed. At this time, the swing arm 3 rotates together with the control lever 2 and separates from the stopper 5.

On the other hand, based on the discrimination of the discriminator 31, the control device 2
2 sends a signal to the solenoid valve 21 to increase the duty value. Then, the atmospheric dilution ratio of the negative pressure signal in the negative pressure passage 8 decreases, and the negative pressure signal introduced into the actuator 4 increases, causing the stopper 5 to move slightly to the left. At this time, actuator 4
is a pressure-responsive type and has a configuration in which after a negative pressure signal is controlled by the solenoid valve 21, the controlled negative pressure signal acts on the diaphragm of the actuator 4 to displace the stopper 5, as shown in the E curve. The stopper 5 stops at a position where the engine rotational speed apparently increases by α with a response delay. Next, when the accelerator pedal is released at point C, the signal S ₄ is transmitted via the accelerator sensor 26.
The discriminator detects that the engine has shifted to idle operation and reduces the duty value of the pulse signal output to the solenoid valve 21 in order to obtain a target idle rotation according to the idle operation state. However, as mentioned above, due to the response delay of the actuator 4, the response delay of the stopper 5 (C'-
D) occurs and the swing arm 3 moves to the stopper 5 before the stopper 5 reaches the target idle position.
After that, the displacement speed of the swing arm 3 is buffered by the balance between the response delay of the actuator 4 and the spring force acting on the accelerator pedal and control lever, and the swing arm 3 stops at the target idle rotation position while drawing a gentle curve. . Therefore, as shown in FIG. 2, the stopper 5 is always located at the idle rotational speed position, and the overshoot area that occurs when the swing arm 3 comes into impactful contact with the stopper when the engine decelerates is the actuator. It is eliminated by the buffering effect of 4.

In the above embodiment, the actuator is configured as a negative pressure responsive type, but it goes without saying that the actuator 4 may be configured as a positive pressure responsive type by replacing the negative pressure generating device 6 with a positive pressure generating device. stomach.

As described above, according to the present invention, when the engine is idling, it is possible to obtain the idle rotation calculated by the control device according to the operating state, so that the idle rotation speed can be adjusted appropriately when auxiliary equipment is used or when the engine is cold. Therefore, the idle rotation can be stabilized and engine stoppage can be prevented. Furthermore, controlling the idle rotation speed according to the engine operating state can save fuel supply amount compared to simple stepwise idle rotation control, and can reduce fuel consumption and improve exhaust emissions. Furthermore, in areas other than engine idling, the stopper is shifted to the fuel increase side relative to the engine idling position caused by the actuator, which reduces the response delay and buffering effect of the pressure-responsive actuator in the transient area from engine deceleration to idling. As a result, the fuel control member returning to the engine idle rotation position is brought into contact with the stopper, which is also about to reach the engine idle rotation position with a delay, before reaching the engine idle rotation position, and the movement of the fuel control member is buffered. Overshoot phenomenon can be prevented, and drivability and exhaust emissions can be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram of a conventional idle rotation control device, Fig. 2 is a graph showing the operation control characteristics of the same as above, Fig. 3 is a schematic system diagram of an idle rotation control device according to the present invention, and Fig. 4 is the same as above. 5 is a graph showing the characteristics of the idling rotation speed corresponding to the cooling water temperature of the same embodiment as above, and FIG. 6 is the idling rotation speed control corresponding to the operating state of the auxiliary equipment. Characteristics diagram, Fig. 7 is a graph showing the characteristics of the actuator stroke and idling rotation speed according to the duty value of the control device, Fig. 8 is a flowchart of the same example, and Fig. 9 is the operation of the same example. It is a graph showing control characteristics. DESCRIPTION OF SYMBOLS 1... Fuel injection pump, 2... Control lever, 3... Swing arm, 4... Actuator, 5... Stopper, 6... Negative pressure generator, 8
... Negative pressure passage, 9 ... Atmospheric release port, 21 ... Solenoid valve, 22 ... Control device, 23 ... Water temperature sensor, 2
4... Rotation sensor, 25... Auxiliary switch, 26
...Accelerator sensor.

Claims (1)

[Claims] 1. A pressure-responsive actuator that is provided with a stopper as an output end within the movement locus of the fuel control member and that controls engine idle rotation by engaging the stopper with the member, and a pressure-responsive actuator that controls dilution of the pressure of a pressure source to a solenoid valve that outputs control pressure to be input to the engine, an engine load sensor, an operating state detection device during engine idling operation, and a detection signal from the sensor and the detection device to detect the idling operating state when idling operation is detected. The engine idle rotation is controlled to a predetermined value by changing the stopper position via the solenoid valve according to the engine speed, and in other operating ranges, the stopper position is shifted to a side where the amount of fuel is increased compared to the engine idle rotation of the predetermined value. and a control device for controlling the operation of the electromagnetic valve so that the stopper comes into contact with a fuel control member to provide a buffer before the stopper reaches the target idle position during an engine deceleration transient. idle rotation control device.