Investigations of Ignition Delay Behavior in a CFR F5 Cetane Rating Engine and a Modern Heavy-Duty Diesel Engine
2022-01-0534
03/29/2022
- Event
- Content
- The American Society for Testing and Materials (ASTM) D613 standardized test method is used to determine the cetane number of diesel fuel oils for use in compression ignition engines. The test method involves use of a variable compression ratio compression ignition CFR F5 test engine. The CFR F5 remains relatively unchanged since its conception, utilizing a swirl prechamber, mechanical jerk fuel pump, and a 10.3 MPa cracking pressure pintle nozzle mechanical injector. Recent efforts to improve the repeatability and reproducibility of the F5 engine involved the development of prototype engines equipped with electronic fuel injection (EFI) systems and upgraded ignition delay measurement instrumentation. These modifications have demonstrated the capability to improve the ASTM D613 precision limits by at least a factor of two. Parameterization of injection strategy has further optimized the test method, producing cycle to cycle variations of ignition delay analogous to modern day compression ignition engines. This study aims to expand on these improvements by identifying and quantifying similarities in ignition characteristics between the EFI F5 and a single-cylinder Caterpillar C9.3B heavy duty diesel engine. Parametrization studies of injection advance and intake air temperature at fixed compression ratio and a gross load of 2 bar were performed on both platforms with primary and secondary reference fuels at varying cetane number. Apparent heat release analysis was performed with prechamber and in-cylinder pressure measurement for the F5 and C9.3B, respectively. Despite its dissimilar engine platform, the F5’s ability to replicate conventional diesel-like combustion characteristics observed in today’s heavy-duty diesel engines further validates it’s importance as the primary cetane rating methodology.
- Citation
- Zeman, J., Nielson, K., and Dempsey, A., "Investigations of Ignition Delay Behavior in a CFR F5 Cetane Rating Engine and a Modern Heavy-Duty Diesel Engine," SAE Technical Paper 2022-01-0534, 2022, https://doi.org/10.4271/2022-01-0534.