Arunachalam, P., Tuner, M., Tunestal, P., and Thern, M., "Humid Air Motor: A Novel Concept to Decrease the Emissions Using the Exhaust Heat," SAE Technical Paper 2017-01-2369, 2017.
Humid air motor (HAM) is an engine operated with humidified inlet charge. System simulations study on HAM showed the waste heat recovery potential over a conventional system. An HAM setup was constructed, to comprehend the potential benefits in real-time, the HAM setup was built around a 13-litre six cylinder Volvo diesel engine. The HAM engine process is explained in detail in this paper. Emission analysis is also performed for all three modes of operation. The experiments were carried out at part load operating point of the engine to understand the effects of humidified charge on combustion, efficiency, and emissions. Experiments were conducted without EGR, with EGR, and with humidified inlet charge. These three modes of operation provided the potential benefits of each system. Exhaust heat was used for partial humidification process. Results show that HAM operation, without compromising on efficiency, reduces NOx and soot significantly over the engine operated without EGR. With HAM around 75-80% of the otherwise waste heat is recuperated (Appendix). This heat is used to reduce the pumping losses and emissions unlike in other waste heat recovery technologies, where the power production is the primary objective.