Volume No. 7 Issue No.: 2 Page No.: 746-755 Oct. - Dec. 2012

 

EFFECT OF EGR INJECTION RATE AND ENGINE LOAD ON CYCLIC VARIATIONS OF AN LPG DIESEL DUAL FUEL ENGINE

 

Poonia M. P.*1 and Mathur Y. B.2

1. Department of Mechanical Engineering, Malaviya National Institute of Technology, Jaipur (INDIA)
2. Suresh Gyan Vihar University, Jaipur (INDIA)

 

Received on : June 25, 2012

 

ABSTRACT

 

Operation of dual fuel engine is limited due to higher cyclic variations in comparison to diesel engine. Cycle by cycle variability is an important constraint on engine operation. It is known, that the cycle-by-cycle variability in cylinder peak pressure, Indicated Mean Effective Pressure (IMEP) and engine speed is the result of variations in the combustion process. The cyclic variations in dual fuel engine tend to be greater than that in the corresponding diesel operation yet much smaller than that of the spark ignition engine. During the present study, efforts have been made to measure the cyclic variations in an LPG diesel dual fuel engine. Effect of Exhaust Gas Recirculation (EGR), the rate of injection and load has been studied in depth. It has been concluded that liquid pilot fuel controlled pre-mixed combustion in first phase remained practically unchanged with change in engine operating conditions and thus do not affect the cyclic variability. Diffusion burning of remained diesel fuel and flame propagation of gaseous fuel in the second stage of combustion is mainly responsible for cyclic variations. Even though, cyclic variations in injection timing were observed but these did not affect the start of ignition point. The Coefficient of Variation (COV) of peak pressure is higher than diesel mode at all temperatures and outputs but the values within 4% up to 60% of full load. COV of peak pressure is mainly affected by the irregularities in the combustion of the diesel + gas air mixture in the second stage of combustion and not by the combustion of the pilot diesel.

 

Keywords : Cyclic variation, Dual fuel engine, Exhaust Gas Recirculation (EGR), LPG, Coefficient of Variation (COV)

 

 

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