Characterization of Engine Performance, Combustion Process and Emission of Diesel/CNG Dual Fuel Engines with Pilot Injection Timing Variation at Low Load

Abstract

The use of CNG on dual fuel diesel engines causes a decrease in engine performance, combustion and increased emissions, especially at low loads, which is affected by the addition of ignition delay period so that the maximum of peak combustion away from the top dead center (TDC). Pilot injection timing acts as an ignition delay controller. This research was carried out using an experimental method on diesel/CNG dual fuel engine a single-cylinder to determine the engine performance, combustion process and emissions characteristics with a variation of pilot injection timing from 110 to 190 BTDC with an interval of 20. The results showed an increase in thermal efficiency of 3.006%, maximum cylinder pressure up to 4.78 MPa, maximum heat release rate of up to 52.05 kJ/m3/0CA, and decrease hydrocarbons (HC), carbon dioxide (CO) and particulate matter (PM) emissions at pilot injection timing 170 BTDC under low load. Likewise, combustion performance has increased marked by a reduction in combustion duration and maximum of peak combustion approaching TDC by advancing the pilot injection timing on diesel/CNGdual fuel engine.