Toyota Motor Corp said on June 12 it would introduce a new, fuel-efficient hybrid engine system for an unspecified existing model later this year in Japan. The system, called THS-M (Toyota Hybrid System-Mild), can be used in many types of automobiles, it said. The system will improve fuel efficiency by about 15 percent compared with conventional gasoline-engine cars by automatically shutting down the engine to prevent idling. Emission of toxic gases will be half of the government's standard for last year, it said. Carmakers around the world have been keen to develop hybrid cars, which are powered by smaller engines with electric motors and a battery pack, and cut toxic gas emissions and fuel consumption. Toyota said it had no plans so far to introduce the system overseas. After the success of its first hybrid, the Prius compact sedan, Toyota decided to launch hybrid minivan Estima on June 15. The automaker sold 60,000 units of the Prius as of April since its launch in December 1997. The model is sold in Japan, the United States and Europe.