Air conditioner for vehicle with heat pump cycle

1. An air conditioner for a vehicle, comprising:

a vapor compression refrigeration cycle including an outdoor heat exchanger configured to perform heat exchange between refrigerant and air outside of a vehicle compartment, and an indoor heat exchanger configured to perform heat exchange between the refrigerant and air to be blown into the vehicle compartment, the vapor compression refrigerant cycle being configured to be switchable between a heat pump cycle in which a heat amount absorbed from the outdoor heat exchanger is radiated to the indoor heat exchanger to heat air to be blown into the vehicle compartment, and a cooler cycle in which a heat amount absorbed from the indoor heat exchanger is radiated to the outdoor heat exchanger;

a heat core configured to heat air to be blown into the vehicle compartment by using coolant of an engine of the vehicle as a heat source; and

a controller configured to control operation of the vapor compression refrigeration cycle, wherein

the controller controls the vapor compression refrigeration cycle to be operated as the cooler cycle so as to perform a defrosting control of the outdoor heat exchanger, and outputs an operation request signal to the engine to cause the engine to be operated, when the controller determines that the outdoor heat exchanger is frosted in a state where the engine is stopped; and

the controller performs the defrosting control of the outdoor heat exchanger when a temperature of the refrigerant flowing through the outdoor heat exchanger is lower than a determination value in the heat pump cycle, and

the controller sets the determination value at a first temperature when the engine is operating, and sets the determination value at a second temperature lower than the first temperature when the engine is stopped.

2. An air conditioner for a vehicle, comprising:

a vapor compression refrigeration cycle including an outdoor heat exchanger configured to perform heat exchange between refrigerant and air outside of a vehicle compartment, and an indoor heat exchanger configured to perform heat exchange between the refrigerant and air to be blown into the vehicle compartment, the vapor compression refrigerant cycle being configured to be switchable between a heat pump cycle in which a heat amount absorbed from the outdoor heat exchanger is radiated to the indoor heat exchanger to heat air to be blown into the vehicle compartment, and a cooler cycle in which a heat amount absorbed from the indoor heat exchanger is radiated to the outdoor heat exchanger;

a heat core configured to heat air to be blown into the vehicle compartment by using coolant of an engine of the vehicle as a heat source;

a controller configured to control operation of the vapor compression refrigeration cycle;

an economic switch configured to switch an economic mode by an operation of a passenger, in which a power saving of the vapor compression refrigeration cycle is preferentially performed; and

an electrical heater which generates heat to heat air to be blown into the vehicle compartment, wherein

the controller controls the vapor compression refrigeration cycle to be operated as the cooler cycle so as to perform a defrosting control of the outdoor heat exchanger, and outputs an operation request signal to the engine to cause the engine to be operated, when the controller determines that the outdoor heat exchanger is frosted in a state where the engine is stopped; and

the controller outputs the operation request signal to the engine and causes the electrical heater to be operated when the controller determines that the outdoor heat exchanger is frosted in a case where the economic mode is set by the economic switch.

3. An air conditioner for a vehicle, comprising:

a vapor compression refrigeration cycle including an outdoor heat exchanger configured to perform heat exchange between refrigerant and air outside of a vehicle compartment, and an indoor heat exchanger configured to perform heat exchange between the refrigerant and air to be blown into the vehicle compartment, the vapor compression refrigerant cycle being configured to be switchable between a heat pump cycle in which a heat amount absorbed from the outdoor heat exchanger is radiated to the indoor heat exchanger to heat air to be blown into the vehicle compartment, and a cooler cycle in which a heat amount absorbed from the indoor heat exchanger is radiated to the outdoor heat exchanger;

a heat core configured to heat air to be blown into the vehicle compartment by using coolant of an engine of the vehicle as a heat source; and

a controller configured to control operation of the vapor compression refrigeration cycle, wherein

the controller controls the vapor compression refrigeration cycle to be operated as the cooler cycle so as to perform a defrosting control of the outdoor heat exchanger, and outputs an operation request signal to the engine to cause the engine to be operated, when the controller determines that the outdoor heat exchanger is frosted in a state where the engine is stopped; and

when the controller performs the defrosting control, a defrosting time for performing the defrosting control is set at a first predetermined time when a temperature of the outside air is lower than a predetermined temperature, and is set at a second predetermined time that is shorter than the first predetermined time when the temperature of the outside air is higher than the predetermined temperature.

4. An air conditioner for a vehicle, comprising:

a vapor compression refrigeration cycle including an outdoor heat exchanger configured to perform heat exchange between refrigerant and air outside of a vehicle compartment, and an indoor heat exchanger configured to perform heat exchange between the refrigerant and air to be blown into the vehicle compartment, the vapor compression refrigerant cycle being configured to be switchable between a heat pump cycle in which a heat amount absorbed from the outdoor heat exchanger is radiated to the indoor heat exchanger to heat air to be blown into the vehicle compartment, and a cooler cycle in which a heat amount absorbed from the indoor heat exchanger is radiated to the outdoor heat exchanger;

a heat core configured to heat air to be blown into the vehicle compartment by using coolant of an engine of the vehicle as a heat source;

a controller configured to control operation of the vapor compression refrigeration cycle;

an electrical heater which generates heat to heat air to be blown into the vehicle compartment, wherein

the controller controls the vapor compression refrigeration cycle to be operated as the cooler cycle so as to perform a defrosting control of the outdoor heat exchanger, and outputs an operation request signal to the engine to cause the engine to be operated, when the controller determines that the outdoor heat exchanger is frosted in a state where the engine is stopped; and

the controller outputs the operation request signal to the engine when a room temperature of the vehicle compartment is lower than a predetermined temperature so that a heating feeling given to a passenger is determined to be lowered in a case where the controller determines that the outdoor heat exchanger is frosted, and

the controller does not output the operation request signal to the engine and causes the electrical heater to be operated, when the room temperature of the vehicle compartment is higher than the predetermined temperature so that the heating feeling given to a passenger is determined to be higher, even in a case where the controller determines that the outdoor heat exchanger is frosted.