Is a zero-carbon emission internal combustion engine possible? The AICE believes it is. The Research Association of Automotive Internal Combustion Engines (using the abbreviation AICE) makes a compelling case for fossil-fueled engines remaining a significant factor, even as electric vehicles become mainstream.

The crux of the AICE argument is that even a pure electric vehicle is not truly carbon-emission free. Fossil fuels are still used to provide the majority of electric power. This results in a net carbon-emission rate for EVs only about 20% less than the most efficient engines running on conventional gasoline or diesel. Thus, a roughly 20% improvement in fuel economy would result in an internal combustion engine that is as carbon-neutral as an electric vehicle.

Engines now convert slightly more than 40% of the energy of the fuel into work (the rest is expelled as heat through the exhaust and cooling systems) (1). To meet this goal, the AICE is forecasting efficiencies of more than 50%. While this may seem like a natural evolution (given that engines in the 1930s were less than 30% efficient), there is a natural upper limit.

From thermodynamics, the Carnot cycle places a firm maximum efficiency on any heat engine. For a gasoline engine with a compression ration of 10, that maximum turns out to be around 60%. Roughly 12% of the energy is currently lost to friction, primarily in the engine and transmission, suggesting that achieving 50% overall efficiency will be quite difficult. AICE envisions several promising strategies, such as increasing effective compression ratio and reducing heat loss through the cylinder.

AICE is a consortium of automotive companies, suppliers, universities and government entities in Japan. The group boasts more than 60 institutional members with a goal of 100 or more within a year. This is a powerful combination of fiscal, regulatory and intellectual capital that is poised to make a big push to prolong the life of the conventional engine.

It should be noted that AICE operates solely in Japan with the stated goal to “contribute to the enduring enhancement of the world-leading industrial strength of Japan.” Although several English-language journalists have reported on AICE (2), there does not appear to be any large-scale analogous organizations in the rest of the world. Indeed, many automakers outside of Japan (such as Volvo (3) and General Motors (4)) have announced their intention to go all-electric in the future, while others are making major investments in that direction. 

Whether the rest of the world is ceding the high ground on internal combustion engines to Japan, or the ICE is due to become obsolete, only time will tell.

REFERENCES
1. Holmberg, K., Andersson, P. and Erdemir, A. (2012), “Global Energy Consumption Due to Friction in Passenger Cars,” Tribology International, 47, pp. 221-234.
2. Available here.
3. Available here.
4. Available here.