VEHICLE TEMPERATURE CONTROL SYSTEM AND TEMPERATURE CONTROL METHOD

To provide vehicle temperature control system and method capable of reliably performing heating operation even when an external temperature is low and heating a heat load through switching to an appropriate operation mode.SOLUTION: A vehicle temperature control system comprises a coolant circuit and a heat medium circuit. The vehicle temperature control system has: a heat pump mode in which a low-pressure side circuit where a heat medium is circulated and a high-pressure side circuit where the heat medium is circulated are formed; a compressor heat source mode in which the heat medium discharged from a high-pressure side heat exchanger flows into a low-pressure side heat exchanger through a temperature control unit and returns to the high-pressure side heat exchanger through an outdoor bypass passage. The vehicle temperature control system also includes a mode selection section. The mode selection section is adapted to select the heat pump mode when a detected external temperature is higher than a switching external temperature related to an intersection point between external temperature-heating performance characteristics of the heat pump mode and the compressor heat source mode and select the compressor heat source mode when the external temperature is lower than the switching external temperature.SELECTED DRAWING: Figure 4 【課題】外気温が低くても加熱能力を担保することができ、より適切なモード切替による熱負荷の加熱が可能な車両用の温調システム・方法の提供。【解決手段】車両用の温調システムは、冷媒回路と、熱媒体回路とを備え、熱媒体が循環する低圧側回路と、熱媒体が循環する高圧側回路とが形成されるヒートポンプモードと、高圧側熱交換器から流出した熱媒体が、温調機器を経由して低圧側熱交換器に流入し、さらに室外バイパス経路を通り、高圧側熱交換器に流入する圧縮機熱源モードと、モード選択部とを備える。モード選択部は、ヒートポンプモードおよび圧縮機熱源モードのそれぞれの外気温度－加熱能力特性の交点に関連する切替外気温度に対し、検知される外気温度が高い場合はヒートポンプモードを選択し、外気温度が低い場合は圧縮機熱源モードを選択するように構成される。【選択図】図４