Effects of Ignition and Injection Perturbation under Lean and Dilute GDI Engine Operation 2015-01-1871
Turbocharged gasoline direct injection (GDI) engines are quickly becoming more prominent in light-duty automotive applications because of their potential improvements in efficiency and fuel economy. While EGR dilute and lean operation serve as potential pathways to further improve efficiencies and emissions in GDI engines, they also pose challenges for stable engine operation.
Tests were performed on a single-cylinder research engine that is representative of current automotive-style GDI engines. Baseline cases were performed under steady-state operating conditions where combustion phasing and dilution were varied to determine the effects on indicated efficiency and combustion stability. Sensitivity studies were then carried out by introducing binary low-high perturbation of spark timing and injection duration on a cycle-by-cycle basis under EGR dilute and lean operation to determine dominant feedback mechanisms. Ignition perturbation was phased early/late of MBT timing, and injection perturbation was set fuel rich/lean of the given air-fuel ratio. COVIMEP was used to define acceptable operation limits when comparing different perturbation cases.
Overall results suggests that combustion phasing is very important for dilute operation while the impact of perturbation is reduced due to increased burn duration compared to the stoichiometric baseline without EGR. Lean operation was found to be very sensitive to injection perturbation, with the effect of perturbations amplified by next-cycle feedback. Due to the longer timescale EGR operation was shown to be less sensitive to next-cycle changes in fueling.
Citation: Wallner, T., Sevik, J., Scarcelli, R., Kaul, B. et al., "Effects of Ignition and Injection Perturbation under Lean and Dilute GDI Engine Operation," SAE Technical Paper 2015-01-1871, 2015, https://doi.org/10.4271/2015-01-1871. Download Citation
Author(s):
Thomas Wallner, James M. Sevik, Riccardo Scarcelli, Brian C. Kaul, Robert M. Wagner
Affiliated:
Argonne National Laboratory, Oak Ridge National Laboratory
Pages: 10
Event:
JSAE/SAE 2015 International Powertrains, Fuels & Lubricants Meeting
ISSN:
0148-7191
e-ISSN:
2688-3627
Related Topics:
Air / fuel ratio
Fuel economy
Exhaust gas recirculation (EGR)
Combustion and combustion processes
Energy conservation
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