Browse Publications Technical Papers 2015-01-1796
2015-09-01

Impact of Effective Compression Ratio on Gasoline-Diesel Dual-Fuel Combustion in a Heavy-Duty Engine Using Variable Valve Actuation 2015-01-1796

Dual-fuel combustion using port-injected gasoline with a direct diesel injection has been shown to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. Reducing compression ratio, in conjunction with a higher expansion ratio using alternative valve timings, decreases compressed charge reactivity while maintain a high expansion ratio for maximum work extraction.Experimental testing was conducted on a 13L multi-cylinder heavy-duty diesel engine modified to operate dual-fuel combustion with port gasoline injection to supplement the direct diesel injection. The engine employs intake variable valve actuation (VVA) for early (EIVC) or late (LIVC) intake valve closing to yield reduced effective compression ratio. Testing was conducted at a mid-load operating condition using a gasoline-diesel dual-fuel operating strategy. The impact on dual-fuel engine performance and emissions with respect to varying effective compression ratio is quantified within this study.As effective compression ratio is reduced, overall massflow through the engine decreases, yielding both higher gas exchange efficiencies and increased heat transfer losses. With constant combustion phasing gasoline/diesel fueling fraction, and NOx emissions held constant, overall brake thermal efficiency remains relatively constant across effective compression ratios.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: Purchase more aerospace standards and aerospace material specifications and save! AeroPaks off a customized subscription plan that lets you pay for just the documents that you need, when you need them.
X