Performance Analysis of a Dual Fuel Engine Using LPG and Diesel with EGR System

Abstract This work is aimed at investigating the performance and emission characteristics of a Dual fuel engine operated with Diesel as primary fuel and ignition source and LPG as secondary fuel with EGR (Exhaust Gas Recirculation) system. In dual fuel operation, much of the energy released comes from the combustion of the gaseous fuel, while only a small amount of diesel fuel provides ignition through timed cylinder injection. The effects of Diesel and LPG substitution ratios, engine speed, and load on the equivalent brake specific fuel consumption and gaseous emissions of hydrocarbons, carbon monoxide and nitrogen oxides are examined for LPG-diesel fuel operation and then compared with the original diesel operation. The concept recirculation of the exhaust gases (EGR), re-burning a part of the exhaust gases is being widely used in many practical situations. The results show that, over a wide range of operating conditions (engine speed, load), the dual fuel engine clearly shows the benefits of reduced NOX emissions. However, under low loads, the results indicate high CO and HC emissions and a higher BSFC when compared to those of the corresponding diesel engine. The LPG addition has been premixed with the engine intake air after the pilot injection of the Diesel in small percentages, in order to improve the engine combustion and to reduce pollutant emissions during the mixing-controlled combustion phase. Experiments show that, using the LPG as an additive fuel, while performing the Diesel fuel main injection keeps the unchanged engine efficiency with respect to the traditional Diesel fuel operation mode.