Toyota announced it will soon introduce vehicles globally with a series of newly-developed, highly efficient gasoline engines that achieve both outstanding thermal efficiency and fuel efficiency improvements of at least 10 percent.
Toyota added the new engines leverage combustion and loss-reduction technologies Toyota has refined in its dedicated hybrid engines.
Two engines will form the base of the new series, said Toyota.
The first is a 1.3-liter gasoline engine using the Atkinson cycle normally used in dedicated hybrid vehicles that achieves a maximum thermal efficiency of 38 percent — top-level said Toyota among mass-produced engines.
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. Toyota said it aims to further improve the fuel efficiency of the engine by utilizing other innovations including an intake port with a new shape that generates a strong tumble flow (whereby the air-fuel mixture flows in a vertical swirl) inside the cylinder, and a cooled exhaust gas recirculation (EGR) system paired with Variable Valve Timing-intelligent Electric (VVT-iE) technology to improve combustion and reduce loss.
The new features, combined with idling stop and other functions, will lead to fuel efficiency gains of approximately 15 percent by comparison with current vehicles.
Meanwhile, a 1.0-liter engine jointly developed with Daihatsu Motor Co., Ltd. has achieved maximum thermal efficiency of 37 percent due to a similar tumble flow-generating intake port, a cooled EGR system, and a high compression ratio. Combination with the idling-stop function and various other fuel consumption reduction technologies allows vehicles to achieve a maximum fuel efficiency improvement of approximately 30 percent over current vehicles.
The new engines will be used in models scheduled for partial redesign in the near future, and a total of 14 engine variations will be introduced globally by 2015.