Fuels & Chemicals

Enhancing Thermal Efficiency for Internal Combustion Engines through Better Fuel Compositions

Fig.: Modifying fuel composition in order to improve thermal efficiency

In the global push for net-zero carbon emissions in the transportation sector, carbon neutral fuels (e.g. biofuels and synthetic fuels produced using renewable energy) have been drawing the spotlight. But because these fuels can only be produced in relatively limited quantities, it will take planning to ensure they are used wisely and effectively. Reaching the goal of net zero carbon will also require enhancing the thermal efficiency of the internal combustion engines used in hybrid vehicles.
For gasoline engines, much attention has focused on a super lean burn, which is a combustion mode in which a volume of air at least twice that required to burn the fuel completely (stoichiometry) is brought into the combustion chamber. We've been experimenting with different combinations of novel fuels and lean burn engine technology in a bid to enhance thermal efficiency.
With a super lean burn, forcing more air through the engine does increase thermal efficiency, but combustion can become unstable due to the leanness of the air-fuel mixture. Through a series of studies, we learned that by modifying the fuel composition, stable combustion could be achieved with much leaner mixtures and thermal efficiency could be improved dramatically.
We will continue with this research aimed at development of liquid fuels that have less of an impact on the environment.