Effect of pilot injection timing, pilot quantity and intake charge conditions on performance and emissions for an advanced low-pilot-ignited natural gas engine

Abstract

Diesel engines may be converted readily to operate Introduction primarily on natural gas using the injection of a diesel pilotDiesel engines are widely used for heavy-duty applito achieve ignition. Advanced low-pilot-ignited natural gas cations and especially for the propulsion of trucks. (ALPING) engines show significant potential to matchEven though the efficiency of these engines is very diesel engines in their part-load and full-load efficiencies.high there are some major problems associated with Experiments were performed to study the effects of pilot them. The most noticed are the NO x and partiinjection timing (−15 to −60°ATDC), pilot quantity, culate emissions. The best possible current diesel intake manifold pressure and intake charge temperature on engine design will not meet the stringent emissions the performance and emissions from an ALPING engine standards that will be applicable in the near future. under half-load (21 kW at 1700 r/min) and full-load (42 kW Homogeneous charge compression ignition (HCCI) at 1700 r/min) conditions. Low NOx emissions (below engines are expected to give very low NO x emissions 0.03 g/kW h at −60°ATDC) with satisfactory fuel converdue to the nature of their combustion process. Howsion efficiency (31 per cent) for half-load and NOx emissions ever, their operation suffers from loss of combustion of 0.2 g/kW h at −60°ATDC with fuel conversion control under high load conditions. Supercharging efficiency of 40 per cent could be obtained for full-load is one way of increasing indicated mean effective engine operation. High HC emissions, 96 g/kW h at −20°p ressure (i.m.e.p.) from HCCI engines [1]. Control of ATDC for half-load and 21 g/kW h at −60°ATDC for the onset of combustion is very important in obtainfull-load operation, were recorded. The NO x emissions ing good performance and emissions in an HCCI showed an interesting trend for varied injection timings engine. A reliable ignition source, which can be a with maximum NOx emissions occurring at −35°ATDC small quantity of diesel pilot, may be effective for such and minimum at −60°ATDC injection timing. Increased a purpose. Successful engine operation with signipilot quantity, intake charge temperature and lower intake ficant reduction in NO x emissions can be achieved manifold pressures resulted in increased NOx emissions in dual-fuel (diesel and natural gas) engines using a and fuel conversion efficiency, and decreased HC emissions.very small diesel pilot quantity [2].

Combustion and emissions characteristics of a dual fuel engine operated on alternative gaseous fuels

“…Numerous research works on experimental and theoretical investigations concerning the dual fuel diesel-natural gas operating mode have been reported over the last decades in the literature [12][13][14][15][16][17][18].…”

A Comparative Study on the Performance and Emission Analysis of a Dual Fuelled Diesel Engine with Karanja Biodiesel and Natural Gas

“…[9][10][11] Moreover, the effects of some important parameters, such as pilot diesel fuel quantity, pilot injection timing, natural gas percentage, natural gas composition, and intake air temperature have also been studied. [12][13][14][15][16] …”

An Experimental Investigation on the Combustion and Emissions Performance of a Natural Gas–Diesel Dual Fuel Engine at Low and Medium Loads

“…Being a low carbon fuel, natural gas produces lower carbon dioxide emissions and generates lower particulate matter (PM) emissions than diesel fuel when burned in an internal combustion engine [1][2][3]. Since heavy duty engine industry predominately uses diesel fuel, replacing diesel fuel by natural gas in internal combustion engines will reduce emissions of carbon dioxide and particulate matter from heavy duty engine industry.…”

“…The 2 Copyright © 2015 by ASME diesel injection timing in [6,7] was fixed. During the studies of pilot-ignited dual fuel combustion, Alla et al [8], Singh et al [2], Krishnan et al [9] and Srinivasan et al [10] found that a change in diesel injection timing had a significant effect on the combustion performance of dual fuel combustion. The combustion performance of dual fuel combustion could also be affected by intake conditions [2,9], exhaust gas recirculation [11], and cetane number of diesel fuel [12].…”

“…During the studies of pilot-ignited dual fuel combustion, Alla et al [8], Singh et al [2], Krishnan et al [9] and Srinivasan et al [10] found that a change in diesel injection timing had a significant effect on the combustion performance of dual fuel combustion. The combustion performance of dual fuel combustion could also be affected by intake conditions [2,9], exhaust gas recirculation [11], and cetane number of diesel fuel [12]. Tablan [13] recently investigated the effect of diesel substitution by natural gas on the performance of a commercially available heavy duty diesel engine, and showed that natural gas could substitute diesel fuel in a dual-fuel heavy-duty diesel engine across multiple speed and load operating points while maintaining thermal efficiency.…”