Fuel-Line Stationary Waves and Variability in CI Combustion During Complex Injection Strategies Available to Purchase

This study investigated the effects of increased injection regime complexity on injector and combustion stability in a naturally aspirated single cylinder diesel engine equipped with a common rail fuel injection system and an instrumented injector. The injection regimes investigated included a single injection, a main injection with a pilot, and a split-main with a pilot. Injector performance was found to be very stable over all injection regimes and did not contribute to variations in combustion stability. Cylinder pressure variation during the initiation of combustion was identified as a potential method of identifying the start of combustion phasing and compared to current methods. Three series of tests were conducted at various speeds and injection pressures to demonstrate the influence of multi-pulse injection phasing on combustion stability and total fuel consumption. These results demonstrate that the presence of a stationary wave in the high-pressure fuel line, induced by an early injection, can dramatically affect the amount of fuel injected in subsequent injections within the same cycle.