Combustion Process and Performance of HCCI Engines under Different Fuels

Abstract

In the wake of industrial advancement, environmental protection has garnered significant attention, particularly concerning engine-generated pollution. The Homogeneous Charge Compression Ignition (HCCI) engine emerges as a promising solution, offering enhanced combustion efficiency with diverse fuels. This research delves into the combustion characteristics of HCCI engines, employing various fuels under assorted conditions. For natural gas HCCI engines, an elevation in the hydrogen ratio bolsters the combustion reaction and augments thermal efficiency. A heightened compression ratio diminishes CO and HC emissions, albeit with a surge in NOx emissions. The n-butanol HCCI engine, utilizing a gasoline and n-butanol fuel mixture, reveals enhanced reactivity and thermal efficiency with an increased mixture ratio. Optimal power is achieved at an excess air coefficient (α) of 0.88, diverging from conventional aviation engines. The coal-based naphtha HCCI engine exhibits amplified thermal efficiency with escalating mixture ratios and temperatures. This comprehensive study underscores the pivotal role of fuel type and operational conditions in optimizing HCCI engine performance, contributing to the reduction of environmental impact while ensuring efficient energy utilization.