Patent ID: 9688118
Date: 2017-06-27
CPC Classifications: B60H

Claim:
1. An air conditioner for a vehicle, comprising: a casing defining an air passage through which air to be blown into a vehicle compartment passes; a cooling heat exchanger arranged in the casing to cool air; a cooling temperature adjusting portion configured to adjust a cooling temperature of air cooled at the cooling heat exchanger, the cooling temperature adjusting portion including a compressor; a dew-point detector configured to detect a physical amount relevant to a dew-point temperature of air flowing to the cooling heat exchanger; a target temperature determining portion configured to determine a target cooling temperature that is a target temperature of the cooling heat exchanger; a cooling temperature control portion configured to control the cooling temperature adjusting portion so that the cooling temperature approaches the target cooling temperature; a cooling temperature detector configured to detect a temperature of air immediately after flowing out of the cooling heat exchanger; and a water-holding amount calculation portion configured to calculate a water-holding amount of an outer surface of the cooling heat exchanger based on an inlet humidity calculated from a detection value of the dew-point detector and an outlet humidity calculated from a detection value of the cooling temperature detector, wherein the water-holding amount calculation portion calculates the water-holding amount by accumulating over time a dehumidified amount that is calculated by subtracting the outlet humidity from the inlet humidity, wherein: a standard water-holding amount is set to be larger than a largest evaporation amount of dew condensation water on the outer surface of the cooling heat exchanger, the largest evaporation amount being estimated depending on change in dew-point temperature of air flowing into the casing by an experiment or a simulation in advance; the target temperature determining portion determines the target cooling temperature to be one of a first target temperature lower than the dew-point temperature by a standard temperature amount and a second target temperature lower than the first target temperature; the target temperature determining portion switches the target cooling temperature between the first target temperature and the second target temperature based on one or more conditions; the target temperature determining portion determines the target cooling temperature as the first target temperature when the water-holding amount is higher than the standard water-holding amount; the target temperature determining portion determines the target cooling temperature as the second target temperature when the water-holding amount is lower than or equal to the standard water-holding amount; and wherein the compressor rotation speed is determined based upon the determined target cooling temperature.