Vehicle air-conditioning system

Patent metadata

Field	Value
Publication number	US-9440514-B2
Application number	US-201013258928-A
Country	US
Kind code	B2
Filing date	Feb 24, 2010
Priority date	Aug 7, 2009
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A vehicle air-conditioning system ( 1 ) includes an HVAC unit ( 2 ) in which a first refrigerant evaporator ( 7 ) and a second refrigerant condenser ( 8 ) are disposed in an air channel ( 6 ) communicating with a vehicle interior space; and a heat pump cycle ( 3 ) in which a refrigerant compressor ( 9 ), a refrigerant switching device ( 10 ), a first refrigerant condenser ( 11 ) that exchanges heat with the outside air, a first expansion valve ( 14 ), and a first refrigerant evaporator ( 7 ) are connected in sequence and in which the second refrigerant condenser ( 8 ) is connected in parallel with the first refrigerant condenser ( 11 ) via the refrigerant switching device ( 10 ). An exhaust-heat recovery circuit ( 23 ) equipped with a second refrigerant evaporator ( 18 ) disposed in a ventilation channel ( 19 ) from the vehicle interior and a second expansion valve ( 17 ) is connected in parallel with the first expansion valve ( 14 ) and the first refrigerant evaporator ( 7 ) of the heat pump cycle ( 3 ).

First claim

The invention claimed is:

1. A vehicle air-conditioning system comprising:
an HVAC unit disposed at the front of the vehicle and configured to include a first refrigerant evaporator and a second refrigerant condenser disposed in an air channel communicating with a vehicle interior space and to blow out an airflow whose temperature is controlled by the first refrigerant evaporator and the second refrigerant condenser and
a heat pump cycle in which a refrigerant compressor, a refrigerant switching device for switching the circulating direction of a refrigerant, a first refrigerant condenser that condenses the refrigerant by exchanging heat with outside air, a first expansion valve, and the first refrigerant evaporator are connected in this order and in which the second refrigerant condenser is connected in parallel with the first refrigerant condenser via the refrigerant switching device,
wherein, the heat pump cycle includes,
an exhaust-heat recovery circuit, equipped with a second refrigerant evaporator disposed in a ventilation channel from the vehicle interior for recovering exhaust heat and a second expansion valve, being connected in parallel with the first expansion valve and the first refrigerant evaporator,
wherein a temperature sensor configured to detect the surface temperature of the second refrigerant evaporator or the blowing air temperature of air that has passed through the second refrigerant evaporator is provided, and when the temperature detected by the temperature sensor falls below a predetermined, the rotational speed of the refrigerant compressor is decreased,
a second expansion-valve bypass circuit that is connected to the exhaust-heat recovery circuit so as to bypass the second expansion valve and that is provided with an open/close valve;
a first connecting circuit that is connected to the exhaust-heat recovery circuit and the heat pump cycle so as to communicate between the outlet side of the second refrigerant evaporator and the inlet side of the first refrigerant condenser and that is provided with a third expansion valve; and
a second connecting circuit that is connected to the heat pump cycle so as to communicate between the outlet side of the first refrigerant condenser and the inlet side of the refrigerant compressor, and
wherein the refrigerant from the second refrigerant evaporator is supplied to the first refrigerant condenser via the third expansion valve provided in the first connecting circuit.

2. The vehicle air-conditioning system according to claim 1 , wherein a first PTC heater for heating air is provided in the air channel upstream of the first refrigerant evaporator and/or downstream of the second refrigerant condenser of the HVAC unit.

3. The vehicle air-conditioning system according to claim 2 , wherein, at the start of heating, the first PTC heater is operated to start a heating operation in a recirculation air intake mode or an outside and inside air intake mixing mode.

4. The vehicle air-conditioning system according to claim 1 , wherein a second PTC heater for heating air is provided upstream of the second refrigerant evaporator in the ventilation channel.

5. The vehicle air-conditioning system according to claim 4 , wherein, at the start of heating, the second PTC heater is operated to start a heating operation in a recirculation air intake mode or an outside and inside air intake mixing mode.

6. The vehicle air-conditioning system according to claim 4 ,
wherein, when the temperature detected by the temperature sensor falls below a predetermined temperature, the output of the second PTC heater is increased.

7. The vehicle air-conditioning system according to claim 6 , wherein the output of the second PTC heater is set to a minimum required output so that the temperature detected by the temperature sensor does not fall below the predetermined temperature.

8. The vehicle air-conditioning system according to claim 4 , further comprising:
a low-pressure sensor for detecting the pressure at the low pressure side of the refrigerant compressor,
wherein, when the pressure detected by the low-pressure sensor falls below a predetermined pressure, the output of the second PTC heater is increased, or the rotational speed of the refrigerant compressor is decreased.

9. The vehicle air-conditioning system according to claim 8 , wherein the output of the second PTC heater is set to a minimum required output so that the pressure detected by the low-pressure sensor does not fall below the predetermined pressure.

10. The vehicle air-conditioning system according to claim 4 , wherein the second PTC heater is disposed away from a location vertically below the second refrigerant evaporator.

11. The vehicle air-conditioning system according to claim 1 , wherein a humidity sensor is provided in the vehicle interior, and wherein a heating operation is performed such that, when window fogging is detected by the humidity sensor during the heating operation in a recirculation air intake mode or an outside and inside air intake mixing mode, the mode is switched to an outside-air intake mode, and the exhaust-heat recovery circuit is operated to recover ventilation exhaust heat with the second refrigerant evaporator.

12. The vehicle air-conditioning system according to claim 1 , wherein the first expansion valve and the second expansion valve are thermostatic automatic expansion valves with solenoid open/close valves, in which solenoid open/close valves are integrated.

13. The vehicle air-conditioning system according to claim 1 , wherein the heat pump cycle is equipped with a receiver for accumulating a liquid refrigerant condensed by the first refrigerant condenser and the second refrigerant condenser, and the receiver includes backflow preventing devices integrally incorporated therein at the individual refrigerant intake ports from the first refrigerant condenser and the second refrigerant condenser.

Assignees

• Kondo Toshihisa
• Nakagawa Nobuya
• Suetake Hideki
• Morishita Masatoshi
• Mitsubishi Heavy Ind Ltd

Inventors

• Kondo Toshihisa
• Nakagawa Nobuya
• Suetake Hideki
• Morishita Masatoshi

Classifications

• F25B5/02

  arranged in parallel · CPC title

• B60H1/3213

  for increasing the efficiency in a vehicle heat pump · CPC title

• B60H1/22

  the heat source being other than the propulsion plant {(B60H1/00492 takes precedence)} · CPC title

• B60H1/2225

  arrangements of electric heaters for heating air · CPC title

• B60H1/3204 Primary

  using compression (B60H1/3233 takes precedence) · CPC title