JP2006176035A - Air-conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the temperature of a coolant discharged from a compressor from exceeding a set discharge temperature even when the engine speed is increased rapidly. <P>SOLUTION: Air conditioning is performed by the evaporation of the coolant discharged from the compressor 1 in an evaporator 5. The compressor 1 is operated by the transfer of a driving force of an engine 7 through the medium of a belt 8 and an electromagnetic clutch 9. Then the temperature of the coolant (discharge temperature ) discharged from the compressor 1 is detected by a discharge temperature sensor 20. When the discharge temperature exceeds the set discharge temperature, an air controller 11 turns off the electromagnetic clutch 9 to the OFF position (disengage), and stops the operation of the compressor 1. Then the air controller 11 turns off the electromagnetic clutch 9 to the OFF position and stops the operation of the compressor 1 even when the engine speed is increased rapidly and it is estimated that the discharge temperature exceeds the set discharge temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner for a vehicle, so that the discharge temperature does not exceed a preset set discharge temperature even when the engine speed rapidly increases and the temperature of the refrigerant discharged from the compressor (discharge temperature) rapidly increases. , So that it can be controlled quickly.

  In order to make the interior environment of automobiles comfortable, vehicle air conditioners are provided. Here, a conventional configuration system of the vehicle air conditioner will be described with reference to FIG.

  As shown in FIG. 3, the refrigeration cycle of the vehicle air conditioner includes a compressor 1, a condenser 2, a receiver 3, an expansion valve 4, an evaporator 5, and a refrigerant pipe 6 that connects these devices. In this refrigeration cycle, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 is sent to the condenser 2, cooled and condensed by the outside air A1, and becomes a refrigerant liquid. The refrigerant liquid adiabatically expands at the expansion valve 4 and evaporates at the evaporator 5 to become refrigerant gas. The refrigerant gas is returned to the compressor 1 after cooling the introduction air A <b> 2 that contacts the evaporator 5.

  The drive source of the compressor 1 is an engine 7 for traveling the vehicle. That is, the driving force of the engine 7 is transmitted to the compressor 1 via the belt 8 and the electromagnetic clutch 9 so that the compressor 1 is operated. Therefore, when the engine 7 is stopped, the compressor 1 does not operate. When the engine 7 is operating, the compressor 1 operates when the electromagnetic clutch 9 is in an ON (connected) state, and the electromagnetic clutch 9 is OFF (opened). ), The compressor 1 does not operate.

  On the other hand, the temperature of the refrigerant discharged from the compressor 1 is detected by a bimetallic discharge temperature switch (discharge temperature thermo) 10. When the discharged refrigerant temperature (discharge temperature Td) exceeds a set discharge temperature (for example, 150 ° C.), the discharge temperature switch 10 is turned off (open state). Further, when the discharge temperature becomes equal to or lower than the set discharge temperature, the discharge temperature switch 10 is turned on (connected state).

  Thus, when the discharge temperature Td exceeds the set discharge temperature and the discharge temperature switch 10 is turned OFF, the electromagnetic clutch 9 is turned OFF and the operation of the compressor 1 is stopped. When the discharge temperature switch 10 is turned on, the electromagnetic clutch 9 is turned on.

  The introduced air A2 passes through the evaporator 5 and becomes cooling air, and the temperature of the cooling air is detected by a cooling air sensor (frost thermo) 12. The detected cooling air temperature is sent to the air conditioner controller 11.

Japanese Patent Laid-Open No. 5-141789

In the prior art described above, the bimetal type discharge temperature switch 10 is used. However, the discharge temperature switch 10 has a large response delay with respect to an increase in the discharge temperature Td that is the temperature of the refrigerant discharged from the compressor 1. There is.
For this reason, when the rotational speed of the engine 7 suddenly rises and the rotational speed of the compressor 1 suddenly rises and the discharge temperature Td suddenly rises, the discharge temperature Td exceeds the set discharge temperature (for example, 150 ° C.). However, the discharge temperature switch 10 is not immediately turned OFF, and the discharge temperature switch 10 is turned OFF after a time delay.
For this reason, the compressor 1 may continue to be driven in a state where the discharge temperature Td exceeds the set discharge temperature, which is a problem from the viewpoint of protection of the compressor 1.

  It should be noted that the state where “the rotational speed of the engine 7 suddenly rises and the rotational speed of the compressor 1 suddenly rises and the discharge temperature Td suddenly rises” is, for example, an automobile that has been stopped for a long time in a parking area on a highway However, there are times when you suddenly enter a high-speed lane and drive at high speed.

  The present invention provides a vehicle air conditioner capable of stopping the drive of a compressor so that the discharge temperature does not exceed a set discharge temperature when the discharge temperature of the refrigerant rises rapidly in view of the above-described conventional technology. For the purpose.

The configuration of the present invention for solving the above problems is as follows.
A refrigeration cycle including a compressor that operates when a driving force of a vehicle traveling engine is transmitted through a clutch;
A temperature sensor that detects the temperature of the refrigerant discharged from the compressor and outputs a detected discharge temperature;
An air conditioner that opens the clutch when the detected discharge temperature detected by the temperature sensor exceeds a preset set discharge temperature, and that connects the clutch when the detected discharge temperature is equal to or lower than the preset set discharge temperature.・ Has a controller
Further, the air conditioner controller has an engine speed / detected discharge temperature characteristic indicating the relationship between the engine speed and the detected discharge temperature for each outside air temperature, and the outside air temperature and the engine speed are transmitted. The engine speed / detected discharge temperature characteristic corresponding to the transmitted outside air temperature is selected, the engine speed change per unit time is obtained, and the engine speed change is determined from the selected engine speed / detected discharge temperature characteristic. An estimated temperature, which is a later refrigerant temperature, is obtained, and when the estimated temperature obtained exceeds the set discharge temperature, the clutch is opened, and when the obtained estimated temperature is equal to or lower than the set discharge temperature, the clutch is brought into a connected state. It is characterized by that.

  In the configuration of the invention, the temperature sensor is a thermistor.

  Even if the engine speed increases rapidly, the driving force transmitted from the engine to the compressor is quickly cut off so that the refrigerant temperature discharged from the compressor does not exceed the preset discharge temperature, and the refrigerant temperature does not overheat. And the compressor can be prevented from thermal damage.

  Hereinafter, embodiments of the present invention will be described based on examples.

A vehicle air conditioner according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the refrigeration cycle of the vehicle air conditioner includes a compressor 1, a condenser 2, a receiver 3, an expansion valve 4, an evaporator 5, and a refrigerant pipe 6 that connects these devices. In this refrigeration cycle, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 is sent to the condenser 2, cooled and condensed by the outside air A1, and becomes a refrigerant liquid. The refrigerant liquid adiabatically expands at the expansion valve 4 and evaporates at the evaporator 5 to become refrigerant gas. The refrigerant gas is returned to the compressor 1 after cooling the introduction air A <b> 2 that contacts the evaporator 5.

  The drive source of the compressor 1 is an engine 7 for traveling the vehicle. That is, the driving force of the engine 7 is transmitted to the compressor 1 via the belt 8 and the electromagnetic clutch 9 so that the compressor 1 is operated. Therefore, when the engine 7 is stopped, the compressor 1 does not operate. When the engine 7 is operating, the compressor 1 operates when the electromagnetic clutch 9 is in an ON (connected) state, and the electromagnetic clutch 9 is OFF (opened). ), The compressor 1 does not operate.

  In this embodiment, the electromagnetic clutch 9 is turned on (connected) / off (released) by the air conditioner controller 11.

On the other hand, the temperature of the refrigerant discharged from the compressor 1 (discharge temperature Td) is detected by a discharge temperature sensor 20 composed of a thermistor. The detected discharge temperature Tdk detected by the discharge temperature sensor 20 is sent to the air conditioner controller 11.
In addition, the discharge temperature sensor 20 comprised with the thermistor has a very small response delay with respect to the temperature rise of a refrigerant | coolant compared with a bimetal type discharge temperature switch.

  The introduced air A2 passes through the evaporator 5 and becomes cooling air, and the temperature of the cooling air is detected by a cooling air sensor (frost thermo) 12. The detected cooling air temperature is sent to the air conditioner controller 11.

  The air conditioner controller 11 and the engine ECU 21 transmit and receive information via a CAN communication network (Controller Area Network) 22. Therefore, the engine speed Ne and the outside air temperature t obtained by the engine ECU 21 are transmitted to the air conditioner controller 11 via the CAN communication network 22. Note that the outside air temperature t here is a temperature detected by a temperature sensor near the engine. Therefore, the outside air temperature t is not a normal air temperature, but a temperature higher than the air temperature due to the heat influence of the engine. It has become.

  When the detected discharge temperature Tdk exceeds the set discharge temperature (150 ° C.), the air conditioner controller 11 turns off the electromagnetic clutch 9 to stop the operation of the compressor 1 so that the discharge temperature Td does not exceed the set discharge temperature. I have to.

  In addition, although detailed operations will be described later, the air conditioner controller 11 determines that the electromagnetic clutch Ne should increase when the engine speed Ne increases rapidly and the detected discharge temperature Tdk exceeds the set discharge temperature (150 ° C.). 9 is turned off to stop the operation of the compressor 1. In this case, since a thermistor with a small detection response delay is used as the discharge temperature sensor 20, the detected discharge temperature Tdk is substantially equal to the discharge temperature Td.

  Here, a method for estimating and determining that “the engine speed Ne suddenly increases and the detected discharge temperature Tdk exceeds the set discharge temperature (150 ° C.)” by the air conditioner controller 11 will be described.

  The air conditioner controller 11 includes a plurality of outside air temperatures t (in this embodiment, outside air temperatures t are 30 ° C., 40 ° C., and 50 ° C.) between the engine speed Ne (rpm) and the detected discharge temperature Tdk. An engine speed / detected discharge temperature characteristic (see FIG. 2) indicating the relationship is set in advance.

Further, when the outside air temperature t is not 30 ° C., 40 ° C., or 50 ° C., the air conditioner controller 11 interpolates the three characteristics shown in FIG. The engine speed / detected discharge temperature characteristic corresponding to is obtained.
For example, if the outdoor temperature t at that time is 35 ° C., the engine rotation when the outside air temperature t is 35 ° C. is obtained by averaging the characteristics of 30 ° C. and 40 ° C. as shown in FIG. It is obtained as the number / detected discharge temperature characteristic.

The air conditioner controller 11 detects the engine speed Ne every unit time (for example, 1 second) and obtains the engine speed change ΔN per unit time interval.
Further, the detected discharge temperature Tdk0 in each unit time is detected.

  First, the air conditioner controller 11 selects an engine speed / detected discharge temperature characteristic according to the transmitted outside air temperature t from a plurality of engine speed / detected discharge temperature characteristics. Here, it is assumed that the outside air temperature t is 40 ° C., and the engine speed / detected discharge temperature characteristic corresponding to the outside air temperature t (40 ° C.) is selected.

  When the engine speed is Ne0 and the detected discharge temperature is Tdk0, and the change in engine speed is changed by ΔN, the air conditioner controller 11 determines the engine speed / detected discharge temperature characteristic when the outside air temperature t is 40 ° C. , It can be seen that the rising temperature of the refrigerant is ΔTdk, and it can be determined that the estimated temperature of the refrigerant (that is, the refrigerant temperature after the change in the rotational speed) becomes Tdk0 + ΔTdk (see FIG. 2). It is determined whether or not the estimated temperature Tdk0 + ΔTdk thus obtained exceeds the set discharge temperature (150 ° C.).

  The air conditioner controller 11 maintains the ON state of the electromagnetic clutch 9 when the estimated temperature Tdk0 + ΔTdk thus determined is equal to or lower than the set discharge temperature, and turns the electromagnetic clutch 9 on when the estimated temperature Tdk0 + ΔTdk exceeds the set discharge temperature. Turn off.

  For this reason, when the engine speed increases rapidly, the discharge temperature exceeds the set discharge temperature before the detected discharge temperature Tdk detected by the discharge temperature sensor 20 with a delayed response reaches the set discharge temperature. When it is estimated that the electromagnetic clutch 9 is turned off, the operation of the compressor 1 can be stopped. Therefore, the compressor 1 can be protected more reliably.

  Even if the discharge temperature sensor 20 fails, the electromagnetic clutch 9 can be turned off when the estimated temperature exceeds the set discharge temperature. Therefore, even if the discharge temperature sensor 20 fails, It is possible to prevent the discharge temperature from exceeding the set discharge temperature. In other words, it performs a double protection function.

  INDUSTRIAL APPLICABILITY The present invention can be used for a vehicle air conditioner, so that the refrigerant temperature does not exceed the set discharge temperature even when the engine speed, which is a driving source of the compressor, rapidly increases and the refrigerant temperature rapidly increases. Can be.

The block diagram which shows the vehicle air conditioner which concerns on the Example of this invention. The characteristic view which shows an engine speed / detection discharge temperature characteristic. The block diagram which shows the conventional vehicle air conditioner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Receiver 4 Expansion valve 5 Evaporator 6 Refrigerant piping 7 Engine 8 Belt 9 Electromagnetic clutch 10 Discharge temperature switch 20 Discharge temperature sensor (thermistor)
21 Engine ECU
22 CAN communication network

Claims (2)

A refrigeration cycle including a compressor that operates when a driving force of a vehicle traveling engine is transmitted through a clutch;
A temperature sensor that detects the temperature of the refrigerant discharged from the compressor and outputs a detected discharge temperature;
An air conditioner that opens the clutch when the detected discharge temperature detected by the temperature sensor exceeds a preset set discharge temperature, and that connects the clutch when the detected discharge temperature is equal to or lower than the preset set discharge temperature.・ Has a controller
Further, the air conditioner controller has an engine speed / detected discharge temperature characteristic indicating the relationship between the engine speed and the detected discharge temperature for each outside air temperature, and the outside air temperature and the engine speed are transmitted. The engine speed / detected discharge temperature characteristic corresponding to the transmitted outside air temperature is selected, the engine speed change per unit time is obtained, and the engine speed change is determined from the selected engine speed / detected discharge temperature characteristic. An estimated temperature, which is a later refrigerant temperature, is obtained, and when the estimated temperature obtained exceeds the set discharge temperature, the clutch is opened, and when the obtained estimated temperature is equal to or lower than the set discharge temperature, the clutch is brought into a connected state. An air conditioner for a vehicle.   2. The vehicle air conditioner according to claim 1, wherein the temperature sensor is a thermistor.

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