High Specific Power Output Direct Injection 2-Stroke Engine Applications

摘要

Whilst Direct In-cylinder injection is now common in both the automotive and non-automotive markets, the very high performance 2-stroke engines pose specific challenges to the application of direct injection due to the increased fuelling levels, the high fuel turn down ratio requirements and the reduced fuel preparation times at high engine operating speeds. In addition, a high performance 2-stroke engine will usually have a highly tuned scavenging system, which puts further demands on the fuel and combustion systems to achieve the desired performance. The fuel and combustion systems must also retain the low emissions to meet the relevant emissions legislation with a minimum level of aftertreatment. This paper briefly discusses the requirements for emissions reduction in high specific output 2-stroke engines, whether it is for a high performance motorcycle application that only uses relatively low loads across the emissions testing cycle or for a highly loaded and high speed snowmobile application. This paper then reviews some of the specific challenges and latest developments for an Air Assisted Direct Injection (ADI) system and the accompanying combustion system to address the operating requirements of high performance and high speed 2-stroke engines.