JP4770562B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner, and more particularly to a vehicle air conditioner that heats a vehicle interior by a heat pump that heats cooling water.

  As a technique for air-conditioning a vehicle interior provided with a heat pump for heating engine coolant, a technique described in Patent Document 1 has been proposed.

In the technique described in Patent Document 1, a heat pump is provided in addition to a hot water heater heated by cooling water of a vehicle driving engine, and a heat exchanger for exhaust heat recovery and cooling water heat recovery are provided in a refrigerant circulation circuit of the heat pump. When the heater starts up at low temperatures, the cooling water circulation circuit of the vehicle drive engine is switched from the hot water heater side with a large amount of heat dissipation to the heat exchanger side for cooling water heat recovery. While reducing the heat dissipation of the cooling water, the heat recovery is recovered by the refrigerant, and the load of the air conditioning engine that drives the heat pump is temporarily increased by the exhaust throttle device to increase the exhaust heat temperature of the air conditioning engine, It has been proposed that exhaust heat be recovered by a refrigerant using an exhaust heat recovery heat exchanger. As a result, the technology described in Patent Document 1 can speed up the heating at low temperatures and speed up the engine warm-up.
JP-A-5-231748

  However, in the technique described in Patent Document 1, it is possible to reduce the heat dissipation of the engine cooling water by using a heat pump and promote warm-up, but the rotation speed of the compressor of the heat pump is determined only by the temperature of the water temperature. For this reason, when there is another heat source, the compressor rotational speed may be set high unnecessarily, the power consumption of the heat pump increases, and there is room for improvement in control of the heat pump.

  The present invention has been made in consideration of the above facts, and an object thereof is to suppress the power consumption of a heat pump.

The invention according to claim 1 in order to achieve the above object, using a refrigerant compressed by a compressor, a heat pump for heating the cooling water of the engine as a heating source of heat at the time of air-conditioning a passenger compartment, the engine an exhaust heat recovery device for heating the cooling water by the heat of exhaust gas discharged, temperature detection means for detecting a temperature of the cooling water, the load detecting means for detecting an engine load, and the exhaust gas discharged from the engine An acquisition means for acquiring each detection result of the exhaust temperature detection means for detecting the exhaust temperature , and as the temperature of the cooling water decreases and the engine load increases based on the acquisition result of the acquisition means reduced, and to decrease according to the exhaust temperature rises, characterized in that it comprises a control means for controlling the rotational speed of the compressor It is.

According to the first aspect of the present invention, in the heat pump, engine coolant that is a heat source for heating is heated by using the refrigerant compressed by the compressor. That is, the passenger compartment can be heated by operating the compressor of the heat pump. Further, in the exhaust heat recovery device, cooling is performed by the heat of exhaust gas exhausted from the engine, but it is heated.

Further, the acquisition means, temperature detecting means for detecting the temperature of the cooling water, the load detecting means for detecting the engine load, and the detection result of the exhaust gas temperature detection means for detecting the exhaust temperature of the exhaust gas discharged from the engine To be acquired.

Then, in the control means, based on the detection result of each detection means acquired by the acquisition means, it decreases as the temperature of the cooling water increases, decreases as the engine load increases , and decreases as the exhaust temperature increases. Thus, the rotation speed of the compressor of the heat pump is controlled. That is, not only the temperature of the cooling water but also the temperature of the cooling water may increase when the engine load is high or the exhaust temperature is high . In this case, it is necessary to suppress the heat pump capacity. The power consumption of the heat pump can be suppressed by controlling the rotation speed of the compressor of the heat pump in consideration of not only the temperature of the engine but also the engine load and the exhaust gas temperature .

The invention according to claim 2 is a heat pump that heats engine coolant, which is a heat source for heating when air-conditioning the vehicle interior, using the refrigerant compressed by the compressor, and heat of exhaust gas discharged from the engine. Obtaining the detection results of the exhaust heat recovery device for heating the cooling water, the temperature detecting means for detecting the temperature of the cooling water, and the exhaust temperature detecting means for detecting the exhaust temperature of the exhaust gas discharged from the engine And control means for controlling the number of revolutions of the compressor so as to decrease as the temperature of the cooling water increases and decreases as the exhaust temperature increases based on the acquisition result of the acquisition means it Ru have as a feature the provided.

According to the second aspect of the present invention, in the heat pump, the coolant that has been compressed by the compressor is used to heat the engine coolant that is a heat source for heating. That is, the passenger compartment can be heated by operating the compressor of the heat pump.

  In the exhaust heat recovery device, the cooling water is heated by the heat of the exhaust gas discharged from the engine. That is, the vehicle interior can be heated by the heat of the exhaust gas.

  In the acquisition means, detection results of the temperature detection means for detecting the temperature of the cooling water and the exhaust temperature detection means for detecting the exhaust temperature of the exhaust gas discharged from the engine are acquired.

  Then, in the control means, based on the detection result of each detection means acquired by the acquisition means, the number of rotations of the compressor of the heat pump so that it decreases as the temperature of the cooling water increases and decreases as the exhaust temperature increases. Is controlled. That is, not only the temperature of the cooling water but also the temperature of the cooling water may be increased by the exhaust heat recovery device. In this case, it is necessary to suppress the heat pump capacity. The power consumption of the heat pump can be suppressed by controlling the rotation speed of the compressor of the heat pump in consideration of the temperature of the heat pump.

The control means obtains the number of rotations of the compressor corresponding to each detection result of each detection means acquired by the acquisition means as in the invention described in claim 3 , and determines the rotation speed of each compressor thus obtained. You may make it control the rotation speed of a compressor so that it may become average rotation speed.

  As described above, according to the present invention, the temperature of the cooling water rises by controlling the rotational speed of the compressor of the heat pump in consideration of not only the temperature of the engine cooling water but also the temperature of the engine load and exhaust gas. Since there is a high possibility that the heat pump capability can be suppressed, the power consumption of the heat pump can be suppressed.

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

  FIG. 1 is a block diagram showing a configuration of a vehicle air conditioner according to an embodiment of the present invention. The vehicle air conditioner 10 according to the present embodiment can be mounted on a hybrid vehicle using the engine 12 and a motor generator as a travel drive source.

  The vehicle air conditioner 10 according to the embodiment of the present invention includes a cooling water cycle 16 for cooling the engine 12 with cooling water, and a refrigerant cycle 26 for circulating the refrigerant.

  An exhaust heat recovery unit 18, a water / refrigerant heat exchanger 20, a water pump 22, and a heater core 24 are provided in a cooling water cycle 16 that cools the engine 12 with cooling water. The cooling water is cooled by the water pump 22. Water is circulated. The water pump 22 may be one that is electrically driven so that the cooling water can be circulated even when the engine 12 is stopped.

  The exhaust heat recovery unit 18 is provided in an exhaust pipe that discharges engine exhaust gas, converts heat into electric power, and is cooled by cooling water in the cooling water cycle 16. That is, heat exchange can be performed between the exhaust pipe and the cooling water, and the cooling water can be heated by the heat of the exhaust pipe.

  The water refrigerant heat exchanger 20 functions as a so-called heat pump that heats the cooling water of the engine 12 using the refrigerant cycle 26 of the vehicle air conditioner.

  The heater core 24 functions as a heat source when the vehicle air conditioner 10 heats the passenger compartment. That is, the cooling water heated by the heat radiation from the engine 12 is radiated by the heater core 24 so that the vehicle interior can be heated.

  The refrigerant cycle 26 includes an electric compressor 28, a water refrigerant heat exchanger 20, a condenser 30, an expansion valve 32, and an evaporator 34, and refrigerant is compressed and circulated by the electric compressor 28. At this time, the refrigerant cycle 26 can also function as the heat pump with the water refrigerant heat exchanger 20. The evaporator 34 has a bypass passage for causing the water-refrigerant heat exchanger 20 to function as a heat pump, and bypasses the refrigerant without passing through the evaporator 34 when functioning as a heat pump.

  When the vehicle air conditioner 10 functions as a cooling system, the refrigerant cycle 26 compresses the refrigerant by the electric compressor 28 to obtain a high-temperature and high-pressure vaporized refrigerant, and the condenser 30 liquefies the high-temperature and high-pressure refrigerant to dissipate heat. The refrigerant that has been liquefied by the expansion valve 32 is rapidly reduced in pressure to be atomized and vaporized by the evaporator 34, thereby cooling the air that passes through the evaporator 34. At this time, the evaporator 34 cools the passing air so as to condense moisture in the air, whereby the air after the evaporator 34 is dehumidified.

  In addition, when the water refrigerant heat exchanger 20 functions as a heat pump, the refrigerant cycle 26 compresses the refrigerant by the compressor 28 to obtain a high-temperature and high-pressure vaporized refrigerant, and the heat of the refrigerant is converted into the water refrigerant heat exchanger 20. The cooling water is heated by dissipating heat to the cooling water of the cooling water cycle 16 that passes through. Further, the refrigerant liquefied after passing through the water refrigerant heat exchanger 20 is decompressed by an expansion valve (not shown) (for example, incorporated in the water refrigerant heat exchanger 20) and absorbed by the capacitor 30, bypassing the evaporator 34. A refrigerant is supplied to the electric compressor 28. By repeating this cycle, the water-refrigerant heat exchanger 20 functions as a heat pump and can heat the cooling water. In addition, you may make it function as heating by dissipating the heat_generation | fever of the water refrigerant | coolant heat exchanger 20 in a vehicle interior.

  The vehicle air conditioner 10 according to the embodiment of the present invention is provided with a control unit 14 to which an electric compressor 28 is connected, and the rotational speed of the electric compressor 28 is controlled by the control unit 14.

  In the vehicle air conditioner 10 according to the embodiment of the present invention, when the vehicle interior is heated, the vehicle interior is heated by heat radiation from the heater core 24 through which the heated cooling water passes, but the cooling that flows through the heater core 24 is performed. Water can be heated by cooling the engine 12, heated by recovering the heat of the exhaust gas with an exhaust heat recovery device, and heated by the water refrigerant heat exchanger 20. By controlling the number of rotations of the electric compressor 28 according to the securing status, the amount of heating by the water refrigerant heat exchanger 20 can be controlled, and the vehicle interior can be heated while reducing the power consumption of the electric compressor 28.

  The control unit 14 is connected to an engine ECU 40 to which sensors such as a water temperature sensor 36 for detecting the temperature of the cooling water and an exhaust temperature sensor 38 for detecting the exhaust gas temperature are connected in order to detect the securing status of each heat source. The control unit 14 acquires the detection results of the water temperature sensor 36 and the exhaust temperature sensor 38 from the engine ECU 40, acquires the engine output as the engine load from the engine ECU 40, and controls the rotational speed of the electric compressor 28. To do. In addition, as an engine output which control unit 14 acquires from engine ECU40, the rotation speed of the engine 12 is acquired, for example.

  Specifically, the control unit 14 decreases based on the acquired coolant temperature, exhaust gas temperature, and engine output, and decreases as the coolant temperature increases, decreases as the exhaust gas temperature increases, and the engine. The rotational speed of the electric compressor 28 is controlled so as to decrease as the output increases. More specifically, the control unit 14 has a map (FIG. 2 (A)) of an electric compressor 28 rotation speed that is predetermined for each water temperature (Tw), and an electric compressor 28 rotation speed that is predetermined for each engine output. (FIG. 2 (B)) and a map (FIG. 2 (C)) of the number of rotations of the electric compressor 28 determined in advance for each exhaust gas temperature (TG) are stored, and the coolant obtained from the engine ECU 40 is stored. Based on the temperature, engine output, and exhaust gas temperature, the rotational speed of the electric compressor 28 corresponding to each is obtained from the map of FIG. In this embodiment, in order to reduce the power consumption of the electric compressor 28, the average value of the rotation speed of the electric compressor 28 read from each map is calculated, and the calculated value is set as the rotation speed of the electric compressor 28. It is supposed to be. Thus, the rotational speed of the electric compressor 28 can be set considering not only the temperature of the engine coolant but also other heat sources, and the power consumption of the electric compressor 28 can be suppressed.

  Then, the effect | action of the vehicle air conditioner 10 concerning embodiment of this invention comprised as mentioned above is demonstrated.

  FIG. 3 is a flowchart showing an example of the flow of the rotational speed setting process of the electric compressor 28 performed by the control unit 14 of the vehicle air conditioner 10 according to the embodiment of the present invention.

  When the heating of the vehicle air conditioner 10 is instructed, first, at step 100, the detection result of the water temperature sensor 36 is acquired from the engine ECU 40, and the routine proceeds to step 102.

  In step 102, the rotation speed f1 (Tw) of the electric compressor 28 corresponding to the detection result of the water temperature sensor 36 is obtained. That is, the rotational speed of the electric compressor 28 corresponding to the detected water temperature is obtained from the map (FIG. 2A) stored in the control unit 14.

  Next, at step 104, the engine output is detected by obtaining the engine speed from the engine ECU 40, and the routine proceeds to step 106.

  In step 106, the rotational speed f2 (E / G) of the electric compressor 28 corresponding to the engine output is obtained. That is, the rotational speed of the electric compressor 28 corresponding to the engine output is obtained from the map (FIG. 2B) stored in the control unit 14.

  Subsequently, at step 108, the detection result of the exhaust temperature sensor 38 is acquired from the engine ECU 40, and the routine proceeds to step 110.

  In step 110, the rotational speed f3 (TG) of the electric compressor 28 corresponding to the detection result of the exhaust temperature sensor 38 is obtained. That is, the rotational speed of the electric compressor 28 corresponding to the detected exhaust gas temperature is obtained from the map stored in the control unit 14 (FIG. 2C).

  In step 112, an average [= AVE (f1 (Tw) + f2 (E / G) + f3 (TG))] of each compressor speed is calculated, and the calculated average value is set as the speed of the electric compressor 28. As a result, the rotation of the electric compressor 28 is controlled, and the process returns to step 100 and the above-described processing is repeated.

  Thus, in the vehicle air conditioner 10 according to the present embodiment, when the water refrigerant heat exchanger 20 of the refrigerant cycle 26 functions as a heat pump for heating, not only the temperature of the engine coolant is detected. In addition, since the rotational speed of the electric compressor 28 is set in consideration of the state of securing heat by the heat source for heating the cooling water (in this embodiment, the engine 12 and the exhaust heat recovery device 18), the rotational speed is higher than necessary. Thus, the vehicle interior can be air-conditioned without rotating the electric compressor 28, and the power consumption of the electric compressor 28 can be suppressed.

  In the above embodiment, the rotational speed of the electric compressor 28 is set based on the temperature of the engine cooling water, the engine output, and the exhaust temperature. However, the present invention is not limited to this. The rotational speed of the electric compressor 28 may be set based on the temperature and the engine output or the exhaust gas temperature. For example, when the exhaust heat recovery unit 18 is not provided, the rotational speed of the electric compressor 28 may be set based on the temperature of the engine cooling water and the engine output.

  In the above embodiment, the average value of the rotational speed of the electric compressor 28 obtained from the temperature of the cooling water, the rotational speed of the electric compressor 28 obtained from the engine output, and the rotational speed of the electric compressor 28 obtained from the exhaust temperature. However, the present invention is not limited to this, and the rotation speed of the electric compressor 28 is determined by appropriately weighting the obtained rotation speed of the electric compressor 28. The number may be set.

It is a block diagram which shows the structure of the vehicle air conditioner concerning embodiment of this invention. (A) is a graph showing a map of the electric compressor rotation speed predetermined for each water temperature, (B) is a graph showing a map of the electric compressor rotation speed predetermined for each engine output, (C) These are graphs showing a map of the number of rotations of the electric compressor 28 predetermined for each exhaust temperature. It is a flowchart which shows an example of the flow of the rotation speed setting process of an electric compressor performed with the control unit of the vehicle air conditioner concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle air conditioner 12 Engine 14 Control unit 16 Cooling water cycle 20 Water refrigerant heat exchanger 26 Refrigerant cycle 28 Electric compressor 36 Water temperature sensor 38 Exhaust temperature sensor 40 Engine ECU

Claims (3)

A heat pump that heats engine cooling water, which is a heat source for heating when air-conditioning the vehicle interior, using the refrigerant compressed by the compressor;
An exhaust heat recovery device for heating the cooling water by the heat of the exhaust gas discharged from the engine;
Temperature detection means for detecting a temperature of the coolant, and obtaining means for obtaining load detecting means for detecting an engine load, and the detection results of the exhaust gas temperature detection means for detecting the exhaust temperature of the exhaust gas discharged from the engine,
Based on the acquisition result of the acquisition unit, so that the drops as the temperature of the cooling water is increased, and the decrease as the engine load increases, and decreases as the exhaust temperature rises, the rotation of the compressor Control means for controlling the number;
A vehicle air conditioner comprising A heat pump that heats engine cooling water, which is a heat source for heating when air-conditioning the vehicle interior, using the refrigerant compressed by the compressor;
An exhaust heat recovery device for heating the cooling water by the heat of the exhaust gas discharged from the engine ;
Acquisition means for acquiring each detection result of the temperature detection means for detecting the temperature of the cooling water and the exhaust temperature detection means for detecting the exhaust temperature of the exhaust gas discharged from the engine;
Control means for controlling the rotational speed of the compressor so as to decrease as the temperature of the cooling water increases and decreases as the exhaust temperature increases based on the acquisition result of the acquisition means;
A vehicle air conditioner comprising The control means obtains the rotation speed of the compressor corresponding to each detection result of each detection means acquired by the acquisition means, and the compressor so as to obtain an average rotation speed of the determined rotation speeds of the compressors. The vehicle air conditioner according to claim 1 or 2, wherein the rotational speed of the vehicle is controlled.

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