Water injection for combustion phasing control and load expansion on an ethanol HCCI engine
2022-01-0545
03/29/2022
- Event
- Content
- Homogeneous charge compression ignition (HCCI) combustion, also known as Controlled Auto-Ignition (CAI), is a low temperature combustion (LTC) mode that offers an alternative to conventional combustion modes. The advantages of HCCI combustion include high conversion efficiency and low NOx emissions. On the other hand, this combustion mode does not have a direct combustion control method, limiting its operational range, being one of the biggest challenges in HCCI mode. High heat release rates and knock initiation limit the high load operation, whereas low loads are limited by low combustion stability. In this context, this paper explores the use of water injection technique to control the combustion phasing and expand the load of an ethanol HCCI engine. The experiments were conducted on a three-cylinder diesel engine and all the exhaust gases from a diesel cylinder were used to achieve the HCCI combustion. In general, the results show that the water injection technique was able to control the charge reactivity, and consequently the combustion phasing, increasing the engine’s load. The water injection reduced combustion speed and heat release rates, which led to a higher combustion duration, a better control of the combustion phasing and ringing intensity. The results indicated an improvement in the initial load of 2 bar of indicated mean effective pressure (IMEP) without water injection to a final load of 6 bar IMEP with water injection. In addition, the ethanol HCCI combustion achieved high indicated efficiencies, ranging from 30 to 40%, while maintaining good combustion stability and low emissions characteristics.
- Citation
- Telli, G., and Martins, M., "Water injection for combustion phasing control and load expansion on an ethanol HCCI engine," SAE Technical Paper 2022-01-0545, 2022, .