Vehicle air-conditioning device

Abstract

A vehicle air-conditioning device is a heat pump type vehicle air-conditioning device including an external heat exchanger that performs heat exchange between refrigerant flowing the inside thereof and outside air. With the vehicle air-conditioning device, a controller functions as a temperature-difference calculation unit that calculates the temperature difference ΔT between the refrigerant in a refrigerant flow path on the exit side of the external heat exchanger and the outside air, and in addition, the controller functions as a frost formation determination unit that determines that frost formation is caused on the external heat exchanger on the basis of the elapsed time to of a state in which the temperature difference ΔT is equal to or larger than a frost-formation temperature difference at which the frost formation may be caused on the external heat exchanger.

Dependencies are inferred from the claim text.