Toyota has unveiled a new range of fuel-efficient engines that promise to achieve fuel efficiency improvements of at least 10 percent over current vehicles.
One of the engines is a newly-developed 1.3-liter petrol that runs on the Atkinson cycle which is typically associated with hybrid engines. As Toyota explains, "Use of the Atkinson cycle provides an increased expansion ratio and reduces waste heat through a high compression ratio (13.5), resulting in superior thermal efficiency." The engine has also been equipped with a distinctive intake port that creates a strong tumble flow - a vertical swirl of the air-fuel mixture - inside the cylinder. This and other innovations should enable the engine to be about 15 percent more fuel efficient than current models.
The company also unveiled a 1.0-liter engine that was jointly-developed with Daihatsu. It eschews the Atkinson cycle but has a similar tumble flow-generating intake port, a cooled EGR system and a high compression ratio. When combined with a start/stop system and "various other fuel consumption reduction technologies," the engine can be up to 30 percent more fuel-efficient than current models.
The engines will be used in several upcoming models and Toyota says we can expect a total of 14 new engine variations to be introduced by 2015.