Operating and Thermal Efficiency Boundary Expansion of Argon Power Cycle Hydrogen Engine

Abstract

The efficiency enhancement of argon power cycle engines through theoretical means has been substantiated. However, the escalation of in-cylinder temperatures engenders abnormal combustion phenomena, impeding the augmentation of compression ratios and practical efficiency. This study presents a comprehensive investigation employing experimental and simulation techniques, aiming to extend the boundaries of thermal efficiency and operational capabilities for hydrogen-powered argon cycle engines. The impact of hydrogen direct injection, intake boost, and port water injection is evaluated in conjunction with an argon power cycle hydrogen engine. The hydrogen direct injection, particularly at an engine speed of 1000 rpm, significantly increases the indicated mean effective pressure from 0.39 MPa to 0.72 Mpa, surpassing the performance of the port hydrogen injection. Manipulating the hydrogen direct injection timing results in the formation of a stratified mixture, effectively attenuating the combustion rate, and resolving the issue of excessively rapid hydrogen combustion within an Ar/O2 environment. The implementation of super lean combustion, combined with intake-boosting, achieves a maximum gross indicated thermal efficiency of 57.89%. Furthermore, the port water injection proves to be an effective measure against knock, broadening the operational range of intake-boosted conditions. Notably, the maximum gross indicated thermal efficiency recorded for the port water injection group under intake-boosted conditions reaches 59.35%.