An innovative Argon/Miller Power Cycle for combustion engine: Thermodynamic Analysis of its Efficiency and its Power Density
2022-01-0510
03/29/2022
- Event
- Content
- Increasing engine efficiency and reducing emissions are fundamental ways to achieve carbon emissions peak and carbon neutrality for transportation and power industry. The Argon Power Cycle (APC) is a novel concept for high efficiency and zero emissions, which is defined as a power cycle with a mixture of argon and oxygen as the working fluid. For an APC, ultra-lean combustion and high dilution combustion are used to increase thermal efficiency, while leading to low power density. To elevate both efficiency and power density, the Miller cycle combined with an APC was considered. The thermal conversion efficiency and the power density of an innovative Argon/Miller Power Cycle were explored through modification of a previous thermodynamic method. Meanwhile, the mixture of H2 and O2 is controlled at a stoichiometric ratio. The results show that with a compression ratio of 7, when the argon dilution ratio rises from 79% to 95%, the thermal conversion efficiency increases from 46.0% to 66.1%. However, the power density reduces by 56%. In comparison, in an APC/Miller cycle with an expansion-compression ratio of 1.5, to get the thermal conversion efficiency of 66.1%, the argon dilution ratio only needs to be increased to 91%. At this argon dilution ratio, the power density is only reduced by 25%. The efficiency and power density enhancing effect of APC/Miller cycle is significant when the expansion-compression ratio ranges from 1.2 to 1.5. Given a ratio of indicated thermal efficiency to thermal conversion efficiency of 80%, with an argon dilution ratio of 91% and an expansion-compression ratio of 1.5, when the compression ratios are 7, 12, 15, and 20, the indicated thermal efficiencies are 53%, 59%, 61%, and 63%, respectively. Compared to Otto cycle, at the same compression ratios, the efficiencies and power densities elevate by 10.7%, 7.0%, 6.1%, and 5.1%, respectively.
- Citation
- Wang, C., JIN, S., Deng, J., and Li, L., "An innovative Argon/Miller Power Cycle for combustion engine: Thermodynamic Analysis of its Efficiency and its Power Density," SAE Technical Paper 2022-01-0510, 2022, .