Sustainable Fuels for Long-Haul Truck Engines: a 1D-CFD Analysis 2024-37-0027

Heavy duty truck engines are quite difficult to electrify, due to the large amount of energy required on-board, in order to achieve a range comparable to that of diesels. This paper considers a commercial 6-cylinder engine with a displacement of 12.8 L, developed in two different versions. As a standard diesel, the engine is able to deliver more than 420 kW at 1800 rpm, whereas in the CNG configuration the maximum power output is 330 kW at 1800 rpm. Maintaining the same combustion chamber design of the last version, a theoretical study is carried out in order to run the engine on Hydrogen, compressed at 700 bar. The study is based on GT-Power simulations, adopting a predictive combustion model, calibrated with experimental results. The study shows that the implementation of a combustion system running on lean mixtures of Hydrogen, permits to cancel the emissions of CO2, while maintaining the same power output of the CNG engine. Moreover, the amount of NOx is very low (<20 ppm), enabling a strong simplification of the after-treatment system, at least in comparison to the original diesel version. Finally, the average brake efficiency of the Hydrogen engine is slightly higher than its CNG counterpart, thanks to the lower heat losses.