Comparison of Propane and Methane Performance and Emissions in a Turbocharged Direct Injection Dual Fuel Engine

Abstract

With increasingly restrictive NOx and particulate matter emissions standards, the recent discovery of new natural gas reserves, and the possibility of producing propane efficiently from biomass sources, dual fueling strategies have become more attractive. This paper presents experimental results from dual fuel operation of a four-cylinder turbocharged direct injection (DI) diesel engine with propane or methane (a natural gas surrogate) as the primary fuel and diesel as the ignition source. Experiments were performed with the stock engine control unit at a constant speed of 1800 rpm, and a wide range of brake mean effective pressures (BMEPs) (2.7–11.6 bars) and percent energy substitutions (PESs) of C3H8 and CH4. Brake thermal efficiencies (BTEs) and emissions (NOx, smoke, total hydrocarbons (THCs), CO, and CO2) were measured. Maximum PES levels of about 80–95% with CH4 and 40–92% with C3H8 were achieved. Maximum PES was limited by poor combustion efficiencies and engine misfire at low loads for both C3H8 and CH4, and the onset of knock above 9 bar BMEP for C3H8. While dual fuel BTEs were lower than straight diesel BTEs at low loads, they approached diesel BTE values at high loads. For dual fuel operation, NOx and smoke reductions (from diesel values) were as high as 66–68% and 97%, respectively, but CO and THC emissions were significantly higher with increasing PES at all engine loads.

Analysis of Ignition Behavior in a Turbocharged Direct Injection Dual Fuel Engine Using Propane and Methane as Primary Fuels

“…The overall experimental setup was similar to that described in Gibson et al [21]. The overall experimental setup was similar to that described in Gibson et al [21].…”

Optical Investigation of Ignition Timing and Equivalence Ratio in Dual-Fuel CNG/Diesel Combustion

“…There is an increased need, whether for environmental, economical, or resource preservation reasons, to operate natural or renewable energy sources. Compared to conventional diesel engines, which is characterized by a high efficiency but a high level of soot particles production, and compared to premixed charge gasoline engines, limited by low efficiencies induced by knocking constraints and pumping losses, gas-fueled diesel engines present higher efficiencies thanks to the reduction of pumping losses and heat transfer [1][2][3][4][5][6][7][8][9][10]. Additionally, the use of low-cetane gaseous fuels such as Compressed Natural Gas (CNG) or methane offers attractive properties in regard to their higher octane number giving higher resistance to knock and to their short carbon chains allowing a systematic reduction in the particulate matter and the NOx emissions [1,[5][6].…”

Injection timing effects on partially premixed diesel–methane dual fuel low temperature combustion

“…Sayin and Canaksi [17] also studied diesel-ignited methane dual fuel combustion in a naturally aspirated single-cylinder CI engine but again within a limited SOI range (327-339 CAD). Polk et al [18] and Gibson et al [19] studied diesel-ignited methane and propane dual fuel combustion in a 1.9-liter turbocharged direct-injected engine, which utilized the stock engine control unit (ECU). The performance during those experiments benefited from boosted intake conditions.…”