The Impact of Fuel Injector Deposits on Fuel Consumption: Correlations & Consequences for Modern Compression Ignition Engines

Fuel injector cleanliness has been identified in the literature as the key factor for maintaining performance in modern compression ignition engines. Fuel injector nozzle deposits have been shown to restrict the mass of fuel that can be injected, resulting in power loss under full load. Several published studies have also investigated changes in fuel economy brought about from fuel injector nozzle deposits, but the majority of these have failed to demonstrate an unambiguous link between fuel economy and fuel injector nozzle deposits. In this paper, we present previously unpublished data from multiple platforms, including light- and heavy-duty, and from vehicle and stationary engine tests, with each showing a strong link between the formation of fuel injector nozzle deposits and associated losses in full-load power and increased brake specific fuel consumption (BSFC). A requirement for a tractable method is that it should be short enough to economically enable multiple repeats to deliver statistically robust findings. Hence, learnings from these earlier studies were subsequently applied to the development of a modern (Tier IV) heavy-duty vehicle test, that showed a statistically significant increase in BSFC associated with fuel injector nozzle deposits built-up in the absence of adequate deposit control additives. Additional results demonstrated repeat findings for renewable diesel, showing continued relevance for understanding and mitigating the effects of nozzle deposits when using paraffinic fuels.