These 2 engines were reserved for Toyota’s gasoline-electric hybrid application, as they operate in Atkinson burning cycle. With improved thermal efficiency achieved through high compression ratio and rapid combustion process, the Atkinson burning cycle provides higher fuel economy. However, there is a catch – reduced power output.
Thermal efficiency of the 1.0 litre engine is 37 percent and that of the bigger engine is 38 percent. These figures are on par with the 38.5 percent efficiency attained in the current engine of Prius hybrid. Toyota’s engineers are targeting above 40 percent thermal efficiency in the coming generation of hybrid engines.
The unaccustomed 1.0 and 1.3 litre engines are equipped with start-stop technology, that halts the engines at stoplights. Toyota believes that this tech enables the new 1.3 litre engine to give 15 percent better fuel economy over current vehicles. Toyota considers this new strategy to have put them one half-a step ahead of its competitors.
Although Toyota seems to have shifted focus to the Atkinson cycle engines, they will be simultaneously advancing in direct injection and turbo-charging technologies to improve fuel economy. The Lexus NX compact crossover to be launched this year is expected to get a 2.0-liter turbo-charged engine and the Toyota Crown Hybrid sedan recently received a direct fuel injection engine.
But Toyota’s increased investment in the electric hybrid route is likely to limit the application of turbo enabled drivetrain, albeit development in progress.
The new 14 engines will be powering hybrid, non-hybrid and larger premium vehicles by 2015. It is unclear at this point which vehicles in particular will get these new engines, but the 2 newly unveiled engines are expected to power non-hybrid compact cars, first in the Japanese market.