Abstract
A 50% reduction in CO2 and fuel consumption has been achieved by the Toyota Hybrid System, which powers the Toyota car «Prius», mass produced since 1997.
This is achieved by the combination of DC asynchronous motors and a newly developed gasoline engine that is optimized in terms of its displacement and heat cycle. Delaying the closing timing of the intake valves effectively separates the compression ratio and expansion ratio, so that the expansion ratio can be set to 13.5:1. This new engine shows better than 230g/kWh BSFC.
Motor-assisted quick start, improved catalyst warm-up, and the elimination of light-load firing allow the system to achieve emissions levels that are only one-tenth of the Japanese regulation.