JP2513176B2 - Idle speed control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for controlling an engine speed (hereinafter referred to as an idle speed) when an engine used as a driving prime mover of a vehicle is idle, and more specifically, a cooling device. The present invention relates to a control device that automatically adjusts an idle speed according to a cooling load that indirectly applies a load to the engine.

[Prior Art] A vehicle air conditioner uses a compressor driven by a running engine. There are two types of compressors, one with a fixed discharge capacity of the refrigerant and one with a continuous or stepwise change. Both are used. This variable capacity compressor needs to be controlled so as to increase the discharge capacity when the cooling load is large, such as in summer. Therefore, in such a case, the load on the engine becomes large, and overheating or engine stoppage may occur when the engine speed is low when the vehicle is stopped or when traffic is congested. In order to prevent this inconvenience, a method of increasing the idle speed when the compressor is driven is conventionally used.

[Problems to be Solved by the Invention] A compressor having a fixed discharge capacity of refrigerant has been controlled by simply being turned on and off. And in this case the compressor
The idle speed at ON was controlled to be larger than the idle speed at compressor OFF. When this method is applied to an air conditioner that uses a compressor whose discharge capacity changes in stages, the idle speed is usually adjusted so that the compressor normally operates at an optimum speed when driven at its maximum discharge capacity. The target value was set. However, even when the cooling load becomes small and the compressor discharge capacity becomes small, the target value of the idle speed remains unchanged and remains large, and even when the vehicle is stopped, the engine speed is high and noise levels are low. Therefore, it was not preferable in terms of energy saving.

As a means for solving these problems, JP-A-58-2209
No. 39, U.S. Patent No. 3010289, the discharge capacity of the compressor is changed stepwise or continuously by the cooling load,
And a method of changing the idle speed accordingly is disclosed. However, these methods are suitable for use in an air conditioner equipped with an external variable type variable displacement compressor in which the variable displacement mechanism of the compressor is electrically controlled by an actuator. It cannot be said to be suitable for use in an air conditioner equipped with an internal variable type variable displacement compressor that is mechanically controlled according to the suction pressure. That is, the external displacement type variable displacement compressor can directly detect the discharge volume of the compressor by directly using the electric signal to the actuator that changes the discharge volume, but the internal variable volume with a mechanical variable volume mechanism can be directly detected. Since such an electric signal cannot be obtained in the compressor of the type, a pressure sensor for measuring the suction pressure in order to detect the discharge amount of the compressor must be separately provided for that purpose, which leads to an increase in cost. The system is complicated and not practical. Therefore, in an air conditioner using an internal variable compressor, it is difficult to control the required idle speed according to the cooling load, and it is more cost-effective than an external variable type because of its cost structure. However, it has been a big problem for practical use of a useful internal variable type variable displacement compressor.

The present invention has been made in view of the above circumstances, and also in an air conditioner using an internal variable type variable displacement compressor,
Idle speed control device that controls the idling speed to the required idling speed according to the cooling load, reduces the fuel consumed by the engine without disturbing the period, and performs the minimum idling The purpose is to provide.

[Means for Solving Problems and Actions Thereof] In order to achieve the above object, the present invention has a control valve (23) that operates in response to an intake pressure of a refrigeration cycle that is changed by a cooling load using an engine as a drive source. An idle speed control device used for an automobile having an air conditioner equipped with a variable displacement compressor (4) that changes a discharge capacity according to the movement of a control valve, comprising: A cooling load sensor (1a) for detecting a physical quantity related to the load; (b) a cooling load calculating means (1b) for inputting a signal from the cooling load sensor to calculate a cooling load of the cooling device; A cooling load comparing means (106) for comparing the cooling load calculated by the cooling load calculating means with a predetermined cooling load set in advance; An engine speed sensor (14) for outputting; and (e) an engine speed comparison means (104) for comparing the engine speed detected by the engine speed sensor with a predetermined engine speed. (F) rotation speed setting means (1e) for estimating the actual discharge capacity of the compressor according to the cooling load calculated by the cooling load calculation means and setting the required target rotation speed of the engine during idling (G) idle speed control means (2) for controlling the idle speed of the engine, and (h) the engine speed is equal to or lower than a predetermined engine speed and the cooling load is equal to or higher than a predetermined cooling load. A rotation speed control device (1f) that sends a signal to the idle rotation speed control means so that the rotation speed of the engine becomes the target rotation speed when it is determined that the capacity of the compressor is large. Adopting technical means that comprises a.

Description will be given below based on the block diagram of the control device shown in FIG.

As the physical quantity related to the cooling load according to the present invention, the outside air temperature, the air temperature inside the vehicle compartment, the amount of solar radiation, the air temperature before and after the evaporator, the air volume passing through the evaporator, the vehicle interior humidity, etc. can be considered. Therefore, as the cooling load sensor 1a for detecting these, a temperature sensor,
A single or a plurality of humidity sensors, rotation speed sensors, pressure sensors, etc. can be selected.

The signal of the physical quantity related to the cooling load detected by the cooling load sensor 1a enters the cooling load calculation device 1b. The cooling load calculation device 1b calculates the cooling load amount at that time from the signal.

The control device 1c controls the idle speed according to the calculated cooling load amount. That is, when the cooling load is large, it is estimated that the load on the engine from the air conditioner is also large.Therefore, in order to prevent the engine from stopping during idling, the idle speed should be higher than the normal idle speed. The idle speed control means 2 is operated.

The controller 1c has an engine speed sensor that detects a physical quantity related to the speed of the running engine. Then, the actual driving state of the engine is determined, and when it is determined that the engine is rotating at a low speed, the idle speed is controlled according to the cooling load amount as described above. This also has the effect of maximizing the braking effectiveness when using engine braking. As the engine speed sensor, a speed sensor that detects the speed of a linear engine, or a pressure sensor or the like to detect the engine oil pressure, to detect the wind pressure during traveling, or to detect the actual speed from a speedometer For example, one that indirectly detects the engine speed can be used alone or in combination of two or more.

The control device 1c includes an engine rotation speed sensor 1d, a rotation speed setting device 1e, and a rotation speed control device 1f, and a target rotation speed of an idle rotation speed according to the cooling load calculated by the cooling load calculation device 1b. Can be decided. That is, the actual engine speed is input from the engine speed sensor 1d to the speed control device 1f and compared with the target speed determined by the speed setting device 1e. Then, the rotation speed control device 1f sends a signal to the idle rotation speed control means 2 so that the idle rotation speed becomes the target rotation speed. This allows smooth control of the idle speed. The idle speed control means 2 includes, for example, a device for controlling the flow rate of the air-fuel mixture from the carburetor by a flow rate control valve driven by an electromagnetic actuator, a device for controlling a throttle valve controlled by an accelerator pedal by an electromagnetic actuator, or the like. Known means can be used. Then, this idle speed can be continuously changed.

The control device 1c may further include a blower control device that sends a signal for controlling a blower that sends an air flow to the condenser of the refrigeration cycle. That is, when the cooling load is small, the capacity of the condenser may be small, and the air volume from the blower may be small, and when the cooling load is large, it is desirable to increase the air volume of the blower. Therefore, the blower control device stores the air flow rate control target value of the cooling load or the idle rotation speed, and increases the air flow rate when the actual value of the cooling load or the idle rotation speed becomes larger than this air flow rate control target value. If it is not, it is preferable to control it to be small.

INDUSTRIAL APPLICABILITY The idle rotation control device of the present invention is applied to an automobile equipped with an air conditioner using a running engine as a drive source. As the compressor of this air conditioner, it is possible to use a so-called internal variable type variable capacity compressor which has a control valve that responds to the suction pressure of the refrigeration cycle and changes the discharge capacity according to the movement of this control valve.

[Embodiment] The embodiment will be described in detail below.

FIG. 2 shows a system diagram of a refrigeration cycle of an automobile using the idle speed control device of the first embodiment of the present invention.

The high-pressure, high-temperature refrigerant gas in the compressor 4 having the variable discharge capacity mechanism 3 is cooled in the condenser 6 by the electric blower 5 to become a liquid, and the gas-liquid separator 7 separates the liquid and the gas. . Then, only the liquid becomes a low-pressure mist at the expansion valve 8 and enters the evaporator 9. In the evaporator 9, the low-pressure refrigerant takes the heat of the air flow from the blower 10 to be vaporized, and the vaporized refrigerant is compressed by the compressor 4 and returns to the liquid again. The refrigeration cycle is configured in this way.

The compressor 4 used here is of a type in which the discharge capacity is continuously varied, and the discharge capacity varying mechanism 3 is schematically shown as a third
Shown in the figure.

A bypass hole 24 that connects the suction chamber B and the compression chamber A is provided, and a spool 23 is provided as a bypass valve that opens and closes the bypass hole 24. At one end of the spool 23, a compression chamber A, which is the end of compression or is in the middle of compression
A control chamber 22 into which the high pressure is introduced is formed, and a spring 25 is arranged at the other end. The position of the spool 23 is controlled by the balance between the pressure in the control chamber 22 and the urging force of the spring 25, and the opening degree of the bypass hole 24 is adjusted.

Reference numeral 20 in FIG. 3 is a pressure regulator, and details of the pressure regulator 20 will be described with reference to FIG. The outer shape of the pressure regulator 20 is formed by the first housing 30 and the second housing 31, and the diaphragm 32 is held between the joint surfaces of the first and second housings 30, 31. Suppression plates 33a and 33b are arranged on the front and back surfaces of the diaphragm 32, respectively. The first chamber 34 formed by the first housing 30 and the diaphragm 32 has a first passage 35 and a second passage 36 that form the control chamber 22.
And to the suction chamber B. A ball valve 37 for opening and closing the passage is arranged in the second passage 36, and the ball valve 37 is interlocked with the movement of the diaphragm 32 via a spring 38 and the restraining plate 33a.

A spring 40 is arranged in a second chamber 39 formed by the second housing 31 and the diaphragm 32. One end of the spring 40 is fixed to the pressing plate 33b and the other end of the spring plate 41 is provided. It is fixed on one side. The other surface of the spring plate 41 is in contact with the tip of an adjusting bolt 42 screwed to the second housing 31, and the adjusting bolt 42
The spring force of the spring 40 is set by moving back and forth.

When the compressor is started, it is necessary to reduce its starting load because it does not give a large impact to the vehicle running engine. That is, it is necessary to open the bypass hole 24 at the time of startup to reduce the discharge capacity of the compressor. In the case of the present example, at the time of starting, since there is no pressure difference between the front and rear surfaces of the spool 23, the spool 23 is driven by the spring 25 and opens the bypass hole 24, so that the spool 23 is started with a small capacity. After the startup, the pressure of the refrigerant sucked into the compressor is high, so that the pressure from the second passage 36 moves the diaphragm 32 to the second chamber 39 side, and the ball valve 37 closes the second passage 36 accordingly. As a result, the communication between the control chamber 22 and the suction chamber B is cut off, and only the control chamber 22 and the compression chamber A are communicated. Therefore, all the high pressure refrigerant from the compression chamber A is guided into the control chamber 22, the pressure of this high pressure refrigerant overcomes the biasing force of the spring 25, and the spool 23 moves to close the bypass hole 24. Therefore, the compressor operates at the maximum capacity and exhibits sufficient cooling capacity.

After that, when the vehicle interior is sufficiently cooled and the suction pressure of the compressor is reduced, the ball valve 37 of the pressure regulator 20 opens the second passage 36, and the high pressure refrigerant in the compression chamber A has the first passage 35.
And escapes to the suction chamber B side through the second passage 36. As a result, the pressure in the control chamber 22 decreases, the spool 23 moves by the urging force of the spring 25, the bypass hole 24 is opened, and the discharge capacity is reduced. The compressor 4 is provided with an electromagnetic clutch 4a. When the compressor 4 has a minimum discharge capacity but its capacity is excessive, the clutch 4a is turned off by another control circuit (not shown) to turn off the evaporator 9. Prevents frost.

The above operation is repeated according to the suction refrigerant pressure of the compressor. However, when such a pressure regulator 20 is used, a pressure sensor or the like for measuring the suction refrigerant pressure in order to detect the discharge amount of the compressor must be separately provided for that purpose, and Knowing the actual load was laborious and very complicated.

The refrigeration cycle shown in FIG. 2 configured as described above has a temperature sensor 12 for detecting the temperature of the air blown at the outlet of the evaporator.
And a temperature sensor that detects the temperature of the air flow from the blower 10.
An idle speed control device 11 including a rotation speed sensor 14 for detecting the rotation speed of a crankshaft (not shown) 11
Is provided. The idle speed control device controls the idle speed control means 16. The idle speed control means 16 is configured as follows.
That is, a thin tube 16c is arranged in the intake pipe 16a of the engine to give a negative pressure to the diaphragm 16b of the power servo, and an electromagnetic valve controlled by the idle speed control device 11 is provided between the diaphragm 16b of the thin pipe 16c and the intake pipe 16a. A valve 16d is provided. Further, the intake pipe 16a is provided with a throttle valve 19 whose opening is adjusted by a link mechanism 18 which is connected to an accelerator pedal 17 by a wire. One end of the wire 16e connected to the rod of the diaphragm 16b is connected to the link mechanism 18.

The control system configured as described above controls as follows.

A signal from the sensor group and a signal indicating the state of the blower switch 15 provided inside the vehicle are idle speed control devices.
Input to 11 and the idle speed control device 11 sends a signal to the idle speed control means 16 to change the idle speed. That is, when the engine speed is high, or when the cooling load is small, the solenoid valve 16d is not driven, the thin tube 16c is closed, the wire 16e is not pulled, and the throttle valve 19 is controlled only by the accelerator pedal 17. Is
The idle speed remains low. When the engine speed drops below a certain value and the cooling load is large, the control device 11 drives the solenoid valve 16d to open the narrow pipe 16c, so that the diaphragm 16d and the intake pipe 16a communicate with each other. Therefore, the wire 16e is pulled by the negative pressure of the engine intake air, and the throttle valve 19 is slightly opened by the link mechanism 18. At the same time, the accelerator pedal 17 is also slightly depressed,
It is configured such that the idle speed becomes high. Further, the controller 11 controls the motor of the blower 5 by interlocking with the control of the idle speed and determining the amount of air blown to the condenser 6.

The processing contents of the control device 11 will be described based on the flowchart shown in FIG.

In step 101, a set value Nset of the engine speed and a set value Qset of the cooling load amount for which the idling speed should be a high value are determined. Here, Nset is determined to be 1300 rpm, for example. In step 102, the signal of each sensor is input,
In step 103, each signal is processed to obtain the actual blower air temperature Tout of the evaporator, the air temperature Tin toward the evaporator, the actual engine speed N, and the state of the blower switch 15 to determine the actual blower 10 temperature. The air volume V is given. Then, in step 104, the actual engine speed N is compared with the set value Nset, and when the actual engine speed N is larger than the set value Nset during traveling or when the engine brake is used, the engine speed is compressed. Since the value is high enough to withstand the load from the machine 4, it is not necessary to increase the idling speed. Therefore, the solenoid valve 16d is turned off in step 109.
Therefore, the throttle valve 19 has an opening degree at which the idling speed becomes a low value when the accelerator pedal 17 is not operated. Further, in conjunction with this control, in step 110, the blower 5
A signal is sent to the motor of the blower 5 so that the amount of blown air becomes a small value, and the process returns to step 102.

In step 104, the actual engine speed N is set to Nse.
If it is smaller than t, the load from the compressor 4 becomes large, which is not preferable for the engine. Therefore, in step 105, the actual cooling load Q is calculated by the following equation, for example.

Q = J · Tout + K · (Tin−Tout) · V + L (J, K, L ... Constant) In step 106, the actual cooling load Q and the set value Qset of the cooling load are compared to determine the actual cooling load. If the quantity Q is smaller than the set value Qset, the discharge capacity of the compressor is a small value, and it is determined that the compressor can withstand the load quantity from the compressor even when the engine speed is small.
9. In step 110, the idling speed is low and the air flow is small. On the other hand, the actual cooling load Q is the set value Qset
If it is larger than that, the discharge capacity of the compressor is a large value, and the engine cannot withstand the load amount from the compressor at that number of revolutions, and there is a risk that problems such as engine stop will occur. is there. Therefore in step 107 the solenoid valve 1
06d is turned on, and the throttle valve 19 is set to an opening such that the idling speed becomes high while the accelerator pedal 17 is not operated by the driver. In order to further increase the cooling capacity of the condenser 6, in step 108, a signal is sent to the motor of the blower 5 so that the blower amount of the blower 5 becomes a large value, and the process returns to step 102.

In this embodiment, the idling speed is reliably controlled in two stages of high value and low value depending on the cooling load amount, and the load on the engine is reduced.

(Second Embodiment) FIG. 6 shows a system diagram of a main part of a refrigeration cycle to which a control device of a second embodiment of the present invention is applied.

In the case of this embodiment, the configuration of the refrigeration cycle is the same as that of the first embodiment except that the processing contents of the idle speed control means and the idle speed control device are different, and the same sensor is provided at the same position. ing. That is, the intake pipe 49 of the engine has a first bypass passage 48 and a second bypass passage 47.
Is provided, and the second bypass passage is provided with a solenoid valve 46 that is ON-OFF controlled by the idle speed control device 45. A throttle valve 50 whose opening is adjusted by an accelerator pedal (not shown) is arranged in the intake pipe 49. That is, the idle speed is determined by the sum of the intake air amounts passing through the first bypass passage and the second bypass passage.

The processing contents of the idle speed control device of the second embodiment and the idle speed control means will be described below with reference to the flowchart of FIG.

 In step 201, the signal from each sensor is input.

In step 202, the actual blown air temperature Tout of the evaporator and the air temperature Tin toward the evaporator are calculated from the signals of the respective sensors, and the air volume V of the blower is given as the actual air volume from the state of the blower switch. Then, the cooling load Q is calculated as in the first embodiment.

In step 203, the load on the engine is estimated from this Q and the target value M of the idle speed is determined. Then, in step 204, the actual engine rotational speed m is calculated from the signal input from the rotational speed sensor, and in step 205, the target value M and the actual value m are compared.

If m ≦ M, that is, if the actual engine speed is lower than the target speed M, the solenoid valve 46 is operated at step 206.
Is turned on to open the second bypass passage 47 to increase the idle rotation speed, and in step 207 a signal is sent to the motor of the blower that cools the condenser so that the air flow rate becomes large.

If m> M, the engine speed is sufficiently high, so in step 208 a signal is sent to turn off the solenoid valve 46, the bypass passage 47 is closed, and the idle speed is reduced. It sends a signal to the fan motor that cools the condenser to a small level.

Conventionally, when the variable displacement compressor used in the first embodiment and the second embodiment is used, it is difficult to finely control the idle speed, but the control device of the present invention performs the above processing. By repeating the operation, the idle speed can be smoothly controlled.

(Third Embodiment) FIG. 8 shows a system diagram of a refrigeration cycle to which the control device of the third embodiment of the present invention is applied.

The refrigeration cycle of FIG. 8 is provided with a temperature sensor 56 for detecting the temperature of the air flowing from the blower 53 to the evaporator 52, and a rotation speed sensor 57 for detecting the rotation speed of the blower 53, which represents each actual value. The signal is input to the idle speed controller 54 and the computer. The idle speed controller 54
A signal from a rotation speed sensor 55 provided near a crankshaft (not shown) for detecting the rotation speed of the engine is input to the. The intake pipe 61 of the engine has a throttle valve 62 whose opening is adjusted by an accelerator pedal (not shown).
And a flow rate control valve 59 driven by an electromagnetic actuator 58 for varying the idling speed is provided in a bypass passage 60 of an intake pipe 61. The signal from the above sensor is processed by the idle speed control device 54, and a signal is sent to the electromagnetic actuator 58 to change the opening degree of the flow rate control valve 59 and change the intake air amount flowing through the bypass passage 60. The rotation speed is changed.
In the case of this embodiment, the opening of the flow rate control valve 59 can be continuously changed, and therefore the idle speed can be continuously changed.

The processing contents of the control device 54 will be described based on the flowchart shown in FIG.

In step 301, signals from the respective sensors are input, and in step 302, the temperature Tin of the air toward the actual evaporator 52 and the air volume V passing through the evaporator 52 are calculated from the signals of the respective sensors. Then, the cooling load Q is calculated from these values. In step 303, the load on the engine is estimated from the value of Q, and the target value M of the idle speed is determined. Then, in step 304, the actual engine speed m is calculated from the signal input from the speed sensor 55,
In step 305, M and m are compared.

If m ≦ M, that is, if the actual engine speed is lower than the target engine speed M, then in step 306 a signal is sent to the actuator 58 in the direction in which the flow rate control valve 59 is further opened slightly with respect to the current opening degree. send. Then, in step 308, the drive voltage of the motor of the blower 64 is controlled so as to slightly increase the amount of air blown by the blower 64 that cools the condenser 63.

If m> M, the engine speed is sufficiently high, so in step 307 a signal is sent to the actuator 58 in the direction to make the flow rate control valve 59 slightly open with respect to the current opening. Then, in step 309, the blower 6 is used to slightly reduce the air flow.
Controls the drive voltage of the 4th motor.

In the control device of the present embodiment, the idle speed can be continuously changed to be equal to the target speed M by repeating the above processing, and smooth control can be performed. or,
When the accelerator pedal is depressed and the vehicle is running, or when the engine brake is used, the engine speed m is greater than the set value M. Therefore, the flow rate control valve 59 of the idle speed control means repeats step 307. Due to this, the fully closed state is achieved.

[Effects of the Invention] As described above, in the control device of the present invention, the cooling load is calculated from the signal of the cooling load sensor, the discharge capacity of the compressor at that time is estimated from this cooling load, and the idle rotation speed corresponding to that is estimated. Control to be. Therefore, even in an air conditioner that uses an internal variable compressor that has a mechanical variable displacement mechanism that changes the discharge capacity in response to the suction pressure of the refrigeration cycle, a pressure sensor that detects the suction pressure, etc. The idling speed can be controlled according to the cooling load without special provision, and the internal rotary type variable displacement compressor, which is more useful than the external variable type, can be effectively used because of its simple structure. Further, since this control is performed when the engine speed is equal to or lower than the predetermined speed and the cooling load is equal to or higher than the predetermined cooling load, such as when the load amount applied to the engine is small, when the vehicle is running or when the engine brake is used. When the engine speed is sufficiently high, the idle speed is not increased unnecessarily to increase the total engine speed, and it is possible to achieve great effects in noise prevention and energy saving.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the control device of the present invention. 2, FIG. 3, FIG. 4 and FIG. 5 are diagrams relating to the first embodiment of the present invention, FIG. 2 is a system diagram of the refrigeration cycle and control device thereof, and FIG. FIG. 4 is a schematic view of the mechanism, FIG. 4 is a cross-sectional view of the pressure regulator used, and FIG. 5 is a flowchart of the processing contents of the control device. 6 and 7 are diagrams relating to the second embodiment of the present invention, FIG. 6 is a system diagram of the essential parts of the refrigeration cycle and control device, and FIG. 7 is a flowchart of the processing contents of the control device. . 8 and 9 are diagrams relating to a third embodiment of the present invention, and FIG. 8 is a system diagram of the refrigeration cycle and control device thereof,
FIG. 9 is a flowchart of the processing contents of the control device. 1, 11, 45, 54 ...... Idle speed control device 12, 13, 56 ...... Temperature sensor 14, 55 ...... Rotation speed sensor 19, 50, 62 ...... Throttle valve 16d, 46 ...... Solenoid valve 58 ...... Electromagnetic actuator

Claims (1)

(57) [Claims] 1. An air conditioner equipped with a variable capacity compressor which has an engine as a drive source and responds to a suction pressure of a refrigeration cycle which varies depending on a cooling load, and which changes a discharge capacity in accordance with the movement of the control valve. An idle speed control device used for a vehicle having: (a) a cooling load sensor for detecting a physical quantity related to a cooling load applied to the air conditioner; and (b) a signal from the cooling load sensor is input. Cooling load calculation means for calculating the cooling load of the cooling device; (c) cooling load comparison means for comparing the cooling load calculated by the cooling load calculation means with a predetermined cooling load. ) An engine speed sensor for detecting the engine speed, and (e) an engine speed detected by the engine speed sensor. Engine speed comparison means for comparing the engine speed with a predetermined engine speed, and (f) estimating the actual discharge capacity of the compressor according to the cooling load calculated by the cooling load calculating means, And (g) idle speed control means for controlling the idle speed of the engine, and (h) engine speed with a predetermined engine speed. When the cooling load is equal to or less than a predetermined cooling load and it is determined that the capacity of the compressor is large, a signal is sent to the idle rotation speed control means so that the rotation speed of the engine becomes the target rotation speed. An idle rotation speed control device comprising: a rotation speed control device for sending.