Performance of Direct Injected Propane and Gasoline in a High Stroke-to-Bore ratio SI Engine: Pathways to Diesel Efficiency Parity with Ultra Low Soot

Conference · Tue Sep 01 00:00:00 EDT 2020

DOI:https://doi.org/10.1177/14680874211006981· OSTI ID:1669762

Splitter, Derek  ^[1]; Storey, John  ^[1]; Boronat Colomer, Vicente  ^[1]; Dal Forno Chuahy, Flavio ^[1]

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1. ORNL

This work explores pathways to achieve diesel-like, high-efficiency combustion with stoichiometric 3-way catalyst compatible combustion in a single-cylinder spark ignition (SI) research engine. A unique high stroke-to-bore engine design (1.5:1) with cooled exhaust gas recirculation (EGR) and high compression ratio (rc) was used to improve engine efficiency by up to 30% compared with a production turbocharged gasoline direct injection spark ignition engine. Engine experiments were conducted with both 91 RON E10 gasoline and liquified petroleum gas (LPG) (i.e., autogas) and were compared to legacy gasoline data on the production engine. Geometric rc of the LSE 13.3:1 was used for both fuels with additional experiments at 16.8:1 for LPG only. Measurements of exhaust soot particle size and number concentrations were made with both fuels. Significant reduction in soot particles across the whole particle size range were achieved with propane due to the elimination of in-cylinder liquid films. The effects of EGR, late intake valve closing (IVC) and fuel characteristics were investigated through their effects on efficiency, combustion stability and soot production. Results of 47% gross thermal efficiency, and 45% net thermal efficiency at stoichiometric engine operation, at up to 17 bar IMEP and 2000 r/min with 16.8:1 rc were achieved with LPG. Estimated brake efficiency values were compared to a contemporary medium duty diesel engine illustrating the benefits of the chosen path for achieving diesel efficiency parity.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1669762
• Resource Relation: Journal Volume: 22; Journal Issue: 12; Conference: 2020 THIESEL Conference on Thermo-and Fluid Dynamic Processes in Direct Injection Engines - Valencia, , Spain - 9/8/2020 8:00:00 AM-9/11/2020 8:00:00 AM
• Country of Publication: United States
• Language: English