[bwilson4web]

http://www.greencarcongress.com/2011...0411.html#more

11 April 2011
Among the R&D projects Toyota Motor is exploring to further lower fuel consumption and emissions are two concepts on a pathway to deliver gasoline engines featuring more than 45% thermal efficiency for application in its future hybrid vehicles, according to Koichi Nakata of Toyota in his presentation today at SAE 2011 High Efficiency IC Engines Symposium in Detroit.

The engine used in the first- and second-generation Prius (the 1.5L 1NZ-FXE) had a thermal efficiency of about 37%; the thermal efficiency of the new 1.8L unit in the third-generation Prius (2ZR-FXE) has a thermal efficiency of about 38%. Toyota is targeting a thermal efficiency of more than 40% with what Nakata called its Future Concept 1, followed by thermal efficiency of more than 45% in Future Concept 2 (which is based on concept 1).

In the 2ZR engine (third-generation Prius), some of the main technologies Toyota applied are the Atkinson cycle with variable valve timing to control intake valve timing, cooled EGR, and lowered friction. (In the 1NZ engine, Toyota reduced friction 21.1% compared to an engine for a comparable conventional vehicle; the 2ZR engine in the newest Prius drops that another 26.8%, in large part by the removal of parasitic loads via the hybrid system (e.g., no alternator).
. . .

This is impressive.

Bob Wilson