DENSO develops Electric Air-conditioning System for Hybrid Buses with 50 percent less power consumption

Denso has developed a smaller, lighter and more efficient air-conditioning system for hybrid buses. The air-conditioning system has an integrated electric compressor, which uses about 50 percent less power compared to Denso’s previous system. The new air-conditioning system has an improved operating efficiency and provides greater comfort to passengers. Unlike engine-powered compressors that are driven by an engine belt, the electric compressor can be precisely controlled according to the situation, which improves operational efficiency and reduces variation in the temperature to provide greater comfort. The new Denso air-conditioning system is Japan’s first mass-produced, electric air-conditioning system integrating an electric compressor with a built-in inverter.

Like traditional buses that use combustion engines, hybrid buses use conventional air-conditioning systems with a compressor driven by an engine belt, so when the engine stops, the air-conditioning system no longer operates. Denso’s new system uses battery power, which allows the air-conditioning system to operate while the engine is stopped. The new Denso air-conditioning system, which can operate while the engine is stopped, will contribute to the widespread use of start and stop systems.The first vehicle to use the new system is the Hino Blue Ribbon City Hybrid, a bus launched by Hino Motors, Ltd., in June 2010.