Investigations on a Homogenous Charge Compression Ignition Engine Operated with Biodiesel and its Emulsions with Water
2022-01-0622
03/29/2022
- Content
- The carbon-neutral biodiesel is a promising renewable substitute for fossil diesel that renders the traditional NOx-PM trade-off into a unidirectional NOx control problem. Low-temperature combustion (LTC) modes such as homogenous charge compression ignition (HCCI) are attractive for obtaining ultra-low NOx and PM emissions. Research works on utilizing biodiesel fuel for HCCI combustion mode are sparsely available. Moreover, the use of biodiesel emulsions in the HCCI combustion mode has not been attempted so far. Based on this premise, the present work explored the potential to utilize biodiesel and its emulsions having 20% and 25% water by volume under HCCI operating conditions. Biodiesel was prepared from Karanja oil, and the same was used to prepare emulsions using heated magnetic stirring apparatus having 3% by volume of the raw oil itself as the surfactant. A production light-duty diesel engine is modified to run in external mixture preparation based HCCI using dedicated air and fuel preheaters to aid in the vaporization of the fuel spray injected at 300 bar pressure using a CRDI system. The engine compression ratio was fixed at 15, which was the maximum operable with biodiesel. The results show that the engine could be operated only up to 20% of the rated load with biodiesel. With biodiesel-water emulsion, 30% of the rated load could be achieved. The maximum cylinder pressure was higher, and the heat release rate was advanced with emulsion compared to neat biodiesel. The brake specific fuel consumption was reduced by 35%, and the brake thermal efficiency increased by 2.4%, along with ultra-low NOx and smoke emissions. The present study shows the potential to utilize biodiesel-water emulsions in HCCI operation with reduced exhaust emissions. Suitable charge dilution methods need to be adopted to extend the HCCI operating load range with emulsions.
- Citation
- Gowrishankar, S., Krishnasamy, A., and J, P., "Investigations on a Homogenous Charge Compression Ignition Engine Operated with Biodiesel and its Emulsions with Water," SAE Technical Paper 2022-01-0622, 2022, .