Analysis of energy and exergy distribution for improving fuel economy of marine low-speed two-stroke diesel engine
2022-01-0463
03/29/2022
- Event
- Content
- Increasingly strict emission regulations and unfavorable economic climate bring severe challenges to energy conservation of marine low-speed engine. Besides traditional methods, the energy and exergy analysis could acknowledge the losses of fuel energy from a global perspective to further improve the engine economy. Therefore, in this study, a thermodynamic model is built based on experimental data to conduct the energy and exergy analysis for marine low-speed engine. Results of energy analysis shows that the exhaust gas accounts for the highest proportion of energy losses, and it rises with the increment of engine load. The proportion from heat transfer is just after the exhaust gas. But, it is negatively correlated to engine load. The energy analysis results indicate that reducing the proportions of exhaust gas and heat transfer is the best way to improve the fuel economy of engine. However, the exergy analysis demonstrates that there is still another more effective approach to reduce the losses of fuel energy. According to the calculated exergy distribution, related analyses show that the exergy destruction is the largest component of exergy losses. Its proportion is about 30%, but it declines with the increment of engine load. The reason is that this exergy destruction is mainly caused by the irreversible combustion process, while for a higher engine load, its degree of irreversible combustion is usually relatively lower. Finally, from the exergy analysis, it could be found that improving the uniformity of combustion could effectively suppress this irreversible combustion, thereby reducing the proportion of exergy destruction and improving the engine fuel economy.
- Citation
- Zhang, H., Deng PhD, K., Wang, D., LONG, W. et al., "Analysis of energy and exergy distribution for improving fuel economy of marine low-speed two-stroke diesel engine," SAE Technical Paper 2022-01-0463, 2022, .