Vehicular heat management system

A vehicular heat management apparatus, comprising:

• a refrigerant circulation line configured to cool or heat a passenger compartment by generating hot air or cold air depending on a flow direction of a refrigerant;
• a cooling water circulation line configured to heat the passenger compartment with waste heat of an engine by allowing cooling water of the engine to circulate through a heater core;
• and a bypass line configured to allow the cooling water on an outlet side of the engine to flow toward an inlet side of the engine;
• and
• the bypass line is configured to connect the outlet side and the inlet side of the engine in a portion of the cooling water circulation line between a refrigerant-cooling water heat exchanger and the engine, and
• wherein the bypass line is connected at one end to a portion of the cooling water circulation line between the outlet of the engine and a branching point of the refrigerant-cooling water heat exchanger and connected at the other end to a portion of the cooling water circulation line between the inlet of the engine and the branching point of the refrigerant-cooling water heat exchanger to form a first cooling water circulation loop for allowing the cooling water on the outlet side of the engine to directly circulate toward the inlet side of the engine, and
• wherein the bypass line has a smaller diameter than a cooling water circulation line that constitutes the first cooling water circulation loop between the engine and the heater core, and
• wherein the cooling water of the engine is not introduced into the bypass line having a relatively high circulation resistance, when the passenger compartment heating heat source is switched to the waste heat of the engine, and the cooling water of the engine circulates along the first cooling water circulation loop between the engine and the heater core, and
• wherein the refrigerant-cooling water heat exchanger and the engine are parallel-connected to the heater core, and
• wherein the refrigerant circulation line includes a compressor, a refrigerant-cooling water heat exchanger, a heat pump mode expansion valve, an outdoor heat exchanger, an air conditioner mode expansion valve and an indoor heat exchanger, and
• wherein the cooling water circulation line connects the heater core, the refrigerant-cooling water heat exchanger of the heat pump side refrigerant circulation line and the engine to each other, and
• wherein the refrigerant-cooling water heat exchanger includes a refrigerant flow path through which the refrigerant in the heat pump side refrigerant circulation line is circulated and a cooling water flow path through which the cooling water in the heater core side cooling water circulation line is circulated, and
• wherein the apparatus, selects one of the engine and the refrigerant-cooling water heat exchanger as a passenger compartment heating heat source depending on the vehicle mode state, the engine cooling water temperature and the refrigerant temperature, in the passenger compartment heating mode, and
• wherein the apparatus includes an engine side cooling water temperature detection sensor, a heater core side cooling water temperature detection sensor and a compressor side refrigerant temperature detection sensor, and
• wherein one of a first heating mode, a second heating mode and a third heating mode is selected and used depending on a cooling water temperature on the side of the engine, a cooling water temperature on the side of the heater core and a refrigerant temperature on the side of the refrigerant-cooling water heat exchanger, and
• wherein a first cooling water in the cooling water circulation line is caused to circulate between the engine and the heater core during the first heating mode, the cooling water in a second cooling water circulation line is caused to circulate between the refrigerant-cooling water heat exchanger and the heater core during the second heating mode, and the cooling water passed through the engine is caused to bypass the heater core and recirculate to the engine while allowing the cooling water in the cooling water circulation line to circulate between the refrigerant-cooling water heat exchanger and the heater core during the third heating mode, and
• wherein a separate cooling water circulation loop of the third heating mode is formed between the engine and the bypass line regardless of a second cooling water circulation loop formed between the heater core and the refrigerant-cooling water heat exchanger, so that the engine cooling water cannot be used as a passenger compartment heating heat source, and
• wherein a third cooling water circulation loop formed between the engine and the bypass line is included in the first cooling water circulation loop formed between the engine and the heater core, and
• wherein when the cooling water temperature of the engine is increased to such a level that the cooling water of the engine can be used as a passenger compartment heating heat source, and when the passenger compartment heating heat source is switched to the waste heat of the engine, the high-temperature engine cooling water circulating between the engine and the bypass line is included in the first cooling water circulation loop between the engine and the heater core.