Skip to Main Content

Climate Control

Climate control systems provide comfort for occupants by heating, ventilating, cooling, reducing humidity and purifying the cabin air. Excellent design and manufacturing practices achieve compact, lightweight, high performing, quiet and efficient systems to exceed our customer’s targets. Keihin offers scalable systems, applying the latest technology to multiple vehicles segments with various powertrains.



The HVAC unit heats the air using heat from the engine coolant and has an evaporator that cools the air through the evaporation of the refrigerant. Options for electric heat can also be applied using a Positive Temperature Coefficient (PTC) heater. The temperature controlled environment occurs after receiving commands from the vehicle controls following inputs from the occupants. Another important function is to defog/defrost windows by utilizing the evaporator to dehumidify the air and drain the condensate outside of the vehicle. The HVAC lowers the humidity by first cooling the air to a lower temperature than what is set by the user, and then part of the cooled air goes through the heater to be warmed up to the set temperature. By using a humidity sensor, the amount of air that is cooled is optimized, enabling a large reduction in operating rate of the compressor. Similarly, the reduction in the operating rate of the compressor for efficiency is realized through the use of the fresh/recirculation air damper that can control the amount of unconditioned outside air entering the HVAC.



Using the outside air from the front of the vehicle, the condenser cools and liquefies the high temperature / high pressure refrigerant that is delivered from the compressor. Keihin’s condensers have high corrosion resistance and high heat rejection performance for the size to proudly be in the top class in the world.


Ambient Sensor

The ambient sensor is an electrical device that measures the air temperature outside of the vehicle and sends the data to the control unit of the climate system.