# US 2014/0360215 A1 · Air conditioner for vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360215 A1 - Document ID: US20140360215A1 - Status: Published application - Kind: A1 - Application number: 14/363,438 - Filed: 2012-12-07 - Published: 2014-12-11 - Earliest claimed: 2011-12-09 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Atsushi Inaba - Web page: https://patentgrep.com/patent/US20140360215A1 ## CPC - B60H 1/00885: {Controlling the flow of heating or cooling liquid, e.g. valves or pumps (B60H1/00899 takes precedence; constructions of valves B60H1/00485)} - B60H 1/00485: {Valves for air-conditioning devices, e.g. thermostatic valves} - B60H 1/3207: {for minimizing the humidity of the air} - B60H 2001/3245: {of air} - B60H 2001/3283: {to control the refrigerant flow} - F25B 2400/0409: for evaporators - F25B 2400/0411: for expansion valves or capillary tubes - F25B 2600/021: Inverters therefor - F25B 2600/111: of condenser fans - F25B 2600/112: of evaporator fans - F25B 2600/2501: Bypass valves - F25B 2600/2513: Expansion valves - F25B 2700/2104: of an indoor room or compartment - F25B 2700/2106: of fresh outdoor air - F25B 2700/21152: at the discharge side of the compressor - F25B 2700/21161: of the fluid heated by the condenser - F25B 2700/21171: of the fluid cooled by the evaporator - B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract When a refrigerant evaporation temperature of an interior evaporator cannot be set lower than a dew-point temperature of air flowing into the interior evaporator in a heating operation, a refrigerant circuit is switched to a normal heating operation mode in which a flow rate of the refrigerant flowing into the interior evaporator is set to zero by allowing the refrigerant to flow toward a bypass passage. In a case where the air cannot be dehumidified by the interior evaporator, an unnecessary heat exchange between the air and the refrigerant in the interior evaporator can be suppressed. Thus, the energy of the vehicle air conditioner can be effectively prevented from being wasted. ## Claims ### Claim 1 A vehicle air conditioner which cools air to be blown into a vehicle interior by using a refrigeration cycle with an evaporator evaporating refrigerant, the vehicle air conditioner comprising: a refrigerant flow-rate control portion controlling a flow rate of the refrigerant flowing into the evaporator; a dew-point temperature detection portion detecting a dew-point temperature of air flowing into the evaporator; and a determination portion determining whether the dew-point temperature detected by the dew-point temperature detection portion is equal to or less than a predetermined reference threshold, wherein the refrigerant flow-rate control portion reduces the flow rate of the refrigerant flowing into the evaporator, when the determination portion determines that the dew-point temperature detected by the dew-point temperature detection portion is equal to or less than the predetermined reference threshold. ### Claim 2 (depends on 1) The vehicle air conditioner according to claim 1, further comprising an evaporator temperature determination portion determining a target refrigerant-evaporation temperature at the evaporator, wherein the predetermined reference threshold is the target refrigerant-evaporation temperature determined by the evaporator temperature determination portion. ### Claim 3 (depends on 2) The vehicle air conditioner according to claim 2, wherein the evaporator temperature determination portion determines the target refrigerant-evaporation temperature based on at least a physical quantity in correlation to a dehumidification load of the vehicle interior. ### Claim 4 (depends on 3) The vehicle air conditioner according to claim 3, wherein the evaporator temperature determination portion determines the target refrigerant-evaporation temperature to be lower as an outside air temperature decreases. ### Claim 5 (depends on 3) The vehicle air conditioner according to claim 3, wherein the evaporator temperature determination portion determines the target refrigerant-evaporation temperature to be lower in accordance with an increase in ratio of introduction of inside air to outside air, introduced into the evaporator. ### Claim 6 (depends on 2) The vehicle air conditioner according to claim 2, wherein the evaporator temperature determination portion determines the target refrigerant-evaporation temperature to be equal to or more than 0° C. ### Claim 7 (depends on 1) The vehicle air conditioner according to claim 1, wherein the predetermined reference threshold is a predetermined fixed threshold. ### Claim 8 (depends on 1) The vehicle air conditioner according to claim 1, wherein the refrigeration cycle includes a bypass passage through which refrigerant flows while bypassing the evaporator, and a refrigerant circuit switching portion switching between a refrigerant circuit for circulating the refrigerant to a side of the evaporator and another refrigerant circuit for circulating the refrigerant to a side of the bypass passage, wherein when the dew-point temperature detection portion determines that the dew-point temperature detected by the determination portion is equal to or less than the predetermined reference threshold, the refrigerant flow-rate control portion controls an operation of the refrigerant circuit switching portion so as to allow the refrigerant to flow to the side of the bypass passage. ### Claim 9 (depends on 1) The vehicle air conditioner according to claim 1, wherein the refrigeration cycle further includes a compressor compressing and discharging the refrigerant, wherein when the determination portion determines that the dew-point temperature detected by the dew-point temperature detection portion is equal to or less than the predetermined reference threshold, the refrigerant flow-rate control portion reduces the refrigerant discharge capacity of the compressor. ### Claim 10 (depends on 1) The vehicle air conditioner according to claim 1, further comprising a heater heating air cooled by the evaporator.