JPH08276727A - Air conditioner for vehicle - Google Patents

Abstract

PURPOSE: To keep blowout temperature stable by providing a means to recover excess calorie from the hot water sent to a heater core in the case where a combustion heater is operated at a minimum fuel quantity. CONSTITUTION: A water refrigerant heat exchanger 4 and a heater core 5 are connected each other through a hot water passage 15 provided with a conveying pump 16, and the heat exchanger 17a built in a combustion heater 17 is connected to this hot water passage 15 in series, and a heat accumulator 18 provided with a heat accumulating materials 18a in its inner passage is also connected to the hot water passage 15 through a bypass passage 19. A three way valve 20 is provided at the connection section to the hot water passage 15 of this bypass passage 19 to vary the hot water quantity introduced to the heat accumulator 18. While the combustion heater 17 is operated in the mode of minimum combustion quantity, the opening degree of the three way valve 20, which corresponds to the difference between the water temperature at the entrance of the heater core 5 and the target temperature is determined from a data table. The rising of the temperature of hot water is thus restricted by recovering heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner for heating the interior of a vehicle by using hot water heated by a combustion heater.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional vehicle air conditioner of this type. In the figure, 101 is a combustion heater,
101a is a heat exchanger built in the combustion heater 101,
Reference numeral 02 is a heater core, 103 is a heat exchanger in the heater 101a
Is connected to the heater core 102, 104 is a water supply pump interposed in the hot water pipe 103, and 105 is a temperature sensor for detecting the heater outlet water temperature.

Reference numeral 106 denotes an evaporator, and the evaporator 106 constitutes a refrigerating circuit together with a compressor, a condenser, an expansion means and the like (not shown). Reference numeral 107 is an air conditioning duct, 108 is a blower fan, 109 is an intake air switching damper, 110 is an air mix damper, and the heater core 102 and the evaporator 106 are arranged inside the air conditioning duct 107.

In this vehicle air conditioner, hot water heated by the combustion heater 101 is sent to the heater core 102, and intake air from the blower fan 108 is heated by the heater core 102 and blown out into the vehicle interior to heat the vehicle interior. To do.

The combustion heater 101 is capable of operating in a plurality of modes having different combustion amounts, that is, a mode in which a maximum combustion amount is obtained and a mode in which a minimum combustion amount is obtained. Is the temperature sensor 10
Based on the heater outlet water temperature detected in step 5, the heater outlet water temperature is preliminarily defined and the engine is operated in the combustion mode.

[0006]

By the way, even when the combustion heater is operated in the minimum combustion amount mode, the heater outlet water temperature rises depending on the relationship with the heating load. Since the upper limit value is set in advance for the heater outlet water temperature, the combustion heater is extinguished at this point if the heater outlet water temperature reaches the upper limit value during operation in the minimum combustion amount mode. When the heater outlet water temperature drops due to this fire extinguishing, the combustion heater is reignited and the operation is restarted.

That is, under the operation in the minimum combustion amount mode, the combustion heater is repeatedly extinguished and ignited, which causes a hunting phenomenon in the heater outlet water temperature within a predetermined temperature range as shown in FIG. However, the blown air temperature also has the problem of causing similar hunting.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle air conditioner capable of obtaining a stable blown air temperature.

[0009]

To achieve the above object, the invention of claim 1 is provided with a combustion heater capable of operating with a minimum combustion amount, and hot water heated by the combustion heater is pumped. In a vehicle air conditioner that heats the interior of the vehicle by sending it to the heater core via the hot water pipeline of the above, the surplus at the time of heating from the hot water sent to the heater core when the combustion heater is operating at the minimum combustion amount. It is characterized in that a means for recovering the amount of heat is provided.

According to a second aspect of the present invention, in the vehicle air conditioner according to the first aspect, the means for recovering the surplus heat amount has a heat storage tank provided with a heat storage material and hot water sent to the heater core in the heat storage tank. By-pass conduit that guides this back to the hot water conduit, introduction amount adjusting means that varies the amount of hot water introduced to the heat storage tank, and when the temperature of the hot water sent to the heater core becomes higher than the target water temperature, the temperature of both The heat recovery control means drives and controls the introduction amount adjusting means so that the introduction amount of hot water into the heat storage tank increases according to the difference.

[0011]

According to the first aspect of the present invention, when the combustion heater is operated with the minimum combustion amount, the surplus heat amount during heating can be recovered from the hot water sent to the heater core to suppress the temperature rise of the hot water.

According to the second aspect of the invention, the amount of heat recovery can be controlled by adjusting the amount of hot water introduced into the heat storage tank according to the difference between the temperature of the hot water sent to the heater core and the target water temperature. Other functions are similar to those of the invention of claim 1.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall construction of a vehicle air conditioner to which the present invention is applied. In the figure, 1 is a variable capacity electric compressor, 2 is an outdoor heat exchanger, 3 is an indoor heat exchanger, 4 is a water-refrigerant heat exchanger, 5 is a heater core, and 6 and 7 are temperature-sensitive expansion valves. , 8 to 11 are solenoid valves, 12 and 13 are check valves, and 14 is a liquid receiver. These devices except the heater core 5 are connected by a refrigerant pipe line to form a heat pump for both heating and cooling.

Reference numeral 15 is a hot water pipe connecting the water-refrigerant heat exchanger 4 and the heater core 5, 16 is a water feed pump interposed in the hot water pipe 15, 17 is a combustion heater for heating water flowing through the hot water pipe 15, 18 Is a heat storage tank for recovering heat by the heat storage material 18a, 19 is a bypass pipe connecting the hot water pipe 15 and the heat storage tank 18, 20 is a three-way valve for varying the amount of hot water introduced into the heat storage tank 18, and 21 is the heater outlet water temperature. (Two) is a temperature sensor, 22 is a temperature sensor that detects the heater core inlet water temperature (Twi), and 23 is a temperature sensor that detects the heat storage material temperature (Tc).

24 is an air conditioning duct, 25 is a blower fan,
Reference numeral 26 is an intake air switching damper, 27 is an air mix damper, and the indoor heat exchanger 3 and the heater core 5 are arranged in the air conditioning duct 24.

The water-refrigerant heat exchanger 4 and the heater core 5 are connected to each other via a hot water pipe 15 having a water feed pump 16, and the hot water pipe 15 has a heat exchanger 17a incorporated in a combustion heater 17. Are connected in series. Further, a heat storage tank 18 is connected to the hot water pipe 15 via a bypass pipe 19, and a three-way valve 20 whose opening degree can be adjusted is provided at a connection portion on the upstream side. In the heater heating mode operation described later, the hot water heated by the combustion heater 17 is sent to the heater core 5 via the hot water pipe line 15 of the pump.

The combustion heater 17 can be operated in five modes with different amounts of combustion. As shown in FIG.
This combustion mode is defined in advance by the heater outlet water temperature Two, and, for example, when the heater outlet water temperature is between 0 and Two5, mode 5 (maximum combustion amount mode) is selected, and the heater outlet water temperature is two through Two1. When it is in the range of, the mode 1 (the mode of the minimum combustion amount) is selected. Heater outlet water temperature T during operation in the minimum combustion mode
When wo rises to Two1 (upper limit value), the combustion heater 17 is extinguished.

The heat storage tank 18 is connected to the bypass conduit 19 at the inlet and outlet of the internal passage, and is provided with the thermal storage material 18a in the internal passage. The heat storage material 18a is configured by sealing water or an organic heat storage material in a container or the like, and is capable of recovering and storing heat from the hot water introduced into the internal passage via the bypass pipe 19.

The three-way valve 20 is connected to the heat storage tank 1 from the hot water pipe 15.
The amount of hot water introduced into the heater 8 is variable, and as shown in FIG.
Is determined on the basis of the difference (ΔT). That is, three-way valve 2
When the opening degree of 0 is 100%, all the hot water flowing through the hot water conduit 15 is guided into the heat storage tank 18 via the bypass conduit 19, and the heat is recovered by the heat storage material 18a, and then the hot water conduit 15 Returned to. When the opening degree of the three-way valve 20 is 0%, hot water is not introduced into the heat storage tank 18 and the heat storage material 18a
No heat recovery is also performed. Incidentally, the above target water temperature Tws is the above T which is determined based on the heating set temperature and the like.
It is a lower temperature than wo1.

The vehicle air conditioner of this embodiment is provided with an air conditioner,
It is possible to operate in five modes: dehumidifying cooling, heating, dehumidifying heating, and heater heating.

The operation in the cooling mode is executed by closing the solenoid valves 8 and 9 and opening the solenoid valves 10 and 11. The refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 2 via the electromagnetic valve 11, and flows into the indoor heat exchanger 3 via the check valve 12, the liquid receiver 14, the electromagnetic valve 10 and the expansion valve 6. Return to compressor 1. The intake air from the blower fan 25 is cooled by the indoor heat exchanger 3 and blown into the vehicle interior.

The operation in the dehumidifying and cooling mode is executed by closing the solenoid valve 9 and opening the solenoid valves 8, 10, 11. A part of the refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 2 via the electromagnetic valve 11, the other part of the discharged refrigerant flows into the water refrigerant heat exchanger 4 via the electromagnetic valve 8, and the check valves are respectively provided. 12, 13 to liquid receiver 14, solenoid valve 10 and expansion valve 6
Flows into the indoor heat exchanger 3 and returns to the compressor 1.
In the water-refrigerant heat exchanger 4, heat is exchanged between the refrigerant and water, and the heated hot water is sent to the heater core 5 via the hot water pipe line 15 of the pump. The intake air from the blower fan 25 is cooled by the indoor heat exchanger 3 and heated by the heater core 5 and blown into the vehicle interior.

The operation in the heating mode is executed by closing the solenoid valves 10 and 11 and opening the solenoid valves 8 and 9. The refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 4 via the electromagnetic valve 8, flows into the outdoor heat exchanger 2 via the check valve 13, the liquid receiver 14 and the expansion valve 7 and flows into the electromagnetic valve 9 Return to compressor 1 via. In the water-refrigerant heat exchanger 4, heat is exchanged between the refrigerant and water, and the heated hot water is sent to the heater core 5 via the hot water pipe line 15 of the pump.
The intake air from the blower fan 25 is heated by the heater core 5 and blown into the vehicle interior.

The operation in the dehumidifying and heating mode is executed by closing the solenoid valve 11 and opening the solenoid valves 8, 9, 10. The refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 4 via the electromagnetic valve 8, passes through the check valve 13 and the liquid receiver 14 and is branched, and a part of the refrigerant is the electromagnetic valve 10 and the expansion valve. 6
Flow into the indoor heat exchanger 3 and return to the compressor 1,
The other part of the refrigerant flows into the outdoor heat exchanger 2 via the expansion valve 7 and returns to the compressor 1 via the electromagnetic valve 9. In the water-refrigerant heat exchanger 4, heat is exchanged between the refrigerant and water, and the heated hot water is sent to the heater core 5 via the hot water pipe line 15 of the pump. The intake air from the blower fan 25 is cooled by the indoor heat exchanger 3 and heated by the heater core 5 and blown into the vehicle interior.

The operation in the heater heating mode is performed by sending the hot water heated by the combustion heater to the heater core 5 via the hot water pipe line 15 of the pump without using a heat pump. The intake air from the blower fan 25 is heated by the heater core 5 and blown into the vehicle interior.

The method of recovering the surplus heat amount when the heater is heated will be described in detail below.

FIG. 4 shows a control system configuration relating to the recovery of the surplus heat quantity. In the figure, 28 is a control unit having a microcomputer configuration, 29 is a heater drive unit that sends a drive signal and a drive stop signal according to the combustion mode to the combustion heater 17, and 30 is a drive according to a determined opening degree for the three-way valve 20. A valve drive unit for sending out a signal, and 31 is an air conditioning temperature setting device provided on the operation panel. Reference numerals 21, 22, and 23 are the above-mentioned temperature sensors that detect the heater outlet water temperature (Two), the heater core inlet water temperature (Twi), and the heat storage material temperature (Tc), respectively.
The control unit 28 stores a program for surplus heat amount recovery control which will be described later, and according to the program, sends a control signal according to the determined opening degree to the valve driving unit 30 and sends a control signal for stopping the operation to the heater driving unit 29. To do.

FIG. 5 shows a program flow for recovering the surplus heat quantity when heating the heater. The control is executed only when the combustion heater 17 is operated in the minimum combustion amount mode (combustion mode 1 in FIG. 2).

As shown in the figure, when the combustion heater 17 is operated in the mode of the minimum combustion amount, the heater core inlet water temperature Twi is compared with the target water temperature Tws, and the heater core inlet water temperature Twi is increased by the increase of the hot water temperature. T
If it becomes higher than ws, heater core inlet water temperature T
The difference (ΔT) between wi and the target water temperature Tws is calculated. Then, the opening degree of the three-way valve 20 corresponding to the calculated ΔT is determined from the data table corresponding to FIG. 3, and the opening degree of the three-way valve 20 is adjusted according to the determined opening degree.

The hot water sent from the combustion heater 17 to the heater core 5 through the hot water pipe 15 is introduced into the heat storage tank 18 in proportion to the opening degree of the three-way valve 20, and in the process of passing through the heat storage tank 18, The heat is recovered by the heat storage material 18a. That is, even if the heater core inlet water temperature Twi temporarily becomes higher than the target water temperature Tws, the temperature of the hot water sent to the heater core 5 is promptly increased by the above-mentioned heat recovery.
It will fall to a temperature close to ws. Further, as the heater core inlet water temperature Twi decreases, the heater outlet water temperature Tw decreases.
Since o also decreases, the heater outlet water temperature Two does not reach its upper limit value in a short time, which reduces the frequency of stopping the operation of the combustion heater 17 during the operation in the minimum combustion amount mode. Will be reduced.

The recovery of the surplus heat amount is continued until the temperature Tc of the heat storage material 18a reaches a predetermined saturation temperature Tcs, and when the temperature Tc of the heat storage material 18a becomes equal to or higher than the saturation temperature Tc, the combustion heater 17 is operated. Extinguished.

As described above, according to this embodiment, the rise of the hot water temperature when the combustion heater 17 is operated in the mode of the minimum combustion amount can be suppressed by the heat recovery by the heat storage material 18a. Moreover, the heater core inlet water temperature Twi
By adjusting the opening degree of the three-way valve 20 according to the difference ΔT between the target water temperature Tws and the target water temperature Tws, as shown in FIG. 6, the heater core 5 is set to the target water temperature Tws regardless of the temperature difference ΔT. It is possible to feed hot water of a stable temperature close to it.

Moreover, since the heater outlet water temperature Two can be prevented from rising to the upper limit value that regulates the operation stop of the combustion heater 17 due to the heat recovery, the operation frequency of the combustion heater 17 can be reduced. As shown in FIG. 6, it is possible to prevent the hunting caused by the stop and restart of the combustion heater 17 and stabilize the temperature of the air blown into the passenger compartment, and reduce the occurrence of Nox and the like due to fire extinguishing and ignition. Can contribute to environmental conservation.

Further, the heat storage material 18a after the heat recovery can be used as an auxiliary heat source when the heating load is high. For example, when the combustion heater 17 is operated in the maximum combustion amount mode, the three-way valve 20 is used. When opened, warm water can be supplementarily heated by the heat recovered by the heat storage material 18a.

The present invention is not limited to the vehicle air conditioner of the illustrated example, but a vehicle for heating the interior of the vehicle by sending hot water heated by the combustion heater to the heater core through the hot water pipe of the pump. It can be widely applied to air conditioners for use and can exhibit the same effect.

[0036]

As described above in detail, according to the first aspect of the present invention, the rise of the hot water temperature when the combustion heater is operated at the minimum combustion amount can be suppressed by the heat recovery. It is possible to reduce the frequency at which the operation of the combustion heater is stopped due to the rise in the hot water temperature and stabilize the air outlet temperature during heating.

According to the second aspect of the invention, the temperature difference is controlled by controlling the heat recovery amount by adjusting the hot water introduction amount into the heat storage tank according to the difference between the hot water temperature sent to the heater core and the target water temperature. Regardless of this, it is possible to send hot water having a stable temperature close to the target water temperature to the heater core. The other effects are the same as those of the invention of claim 1.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle air conditioner to which the present invention has been applied.

FIG. 2 is a diagram showing a relationship between a heater outlet water temperature and a combustion mode in a combustion heater.

FIG. 3 is a diagram showing a relationship between ΔT and a three-way valve opening degree.

FIG. 4 is a block diagram of a control system related to recovery of surplus heat amount.

FIG. 5 is a diagram showing a program flow of surplus heat amount recovery control.

FIG. 6 is a diagram showing the behavior of heater outlet water temperature, heater core inlet water temperature, and blown air temperature according to the present invention.

FIG. 7 is a configuration diagram of a conventional vehicle air conditioner.

FIG. 8 is a diagram showing behaviors of a conventional heater outlet water temperature and a blown air temperature.

[Explanation of Codes] 5 ... Heater core, 15 ... Hot water pipeline, 16 ... Water pump,
17 ... Combustion heater, 18 ... Heat storage tank, 18a ... Heat storage material, 1
9 ... Bypass line, 20 ... Three-way valve 21, 22, 23 ...
Temperature sensor, 28 ... Control unit, 29 ... Heater drive unit, 30
… Valve drive.

Claims (2)

[Claims] 1. A combustion heater capable of operating with a minimum combustion amount is provided, and hot water heated by the combustion heater is sent to a heater core via a hot water pipe line of a pump to heat the interior of the vehicle. In the vehicle air conditioner, a means for recovering an excess heat amount during heating from hot water sent to the heater core when the combustion heater is operating at the minimum combustion amount is provided, apparatus. 2. A means for collecting surplus heat, a heat storage tank provided with a heat storage material, and a bypass pipe for guiding hot water sent to a heater core from the hot water pipe to the inside of the heat storage tank and returning it to the hot water pipe. An introduction amount adjusting means for varying the introduction amount of hot water to the heat storage tank, and when the temperature of the hot water sent to the heater core becomes higher than the target water temperature, the introduction amount of the hot water to the heat storage tank is changed according to the temperature difference between the two. The vehicle air conditioner according to claim 1, further comprising: a heat recovery control unit that drives and controls the introduction amount adjustment unit so as to increase.