Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy.
The efficiency by which they do so is measured in terms of "thermal efficiency", and most gasoline combustion engines average around 20 percent thermal efficiency. Diesels are typically higher--approaching 40 percent in some cases.
Toyota has now developed a new gasoline engine which it claims has a maximum thermal efficiency of 38 percent--greater than any other mass-produced combustion engine.
The new units, 1.0 and 1.3-liters in capacity, should enable 10-15 percent greater economy than their existing equivalents.
Toyota has applied several familiar technologies to its engines to achieve these levels of efficiency.
One of these is the same combustion cycle used in the firm's hybrid models--the Atkinson cycle.