Impacts of Varied Injection Timing on Emission Levels, Combustion Efficiency, and Performance of Biodiesel Engines

Abstract

Numerous studies have aimed to optimize fuel economy and minimize pollutants during the transition from diesel to biodiesel engines. However, a conspicuous void in these studies is the determination of optimal injection timing for biodiesel fuel. This oversight can culminate in escalated emission levels, increased brake-specific fuel consumption, and potential engine knocking. The present study seeks to address this gap by examining the combustion efficiency of biodiesel engines under six distinct fuel injection timings (320, 325, 330, 335, 340, and 345). Biodiesel fuel combustion was simulated using the ANSYS FLUENT software, with numerical simulations performed on the AV1 (Kirloskar) diesel engine operating at an engine speed of 1500 rpm, utilizing biodiesel as a diesel fuel substitute. The simulation results revealed that advancing the start of fuel injection augments the combustion characteristics of the biodiesel engine. Conversely, retarding the start of fuel injection resulted in a decrease in both the NOx and CO fractions. In particular, CO mass fraction values within the engine demonstrated a decrease from 0.133743891 to 0.004889395 for fuel injection timings of 40 BTC to 20 BTC respectively. Similarly, nitric oxide mass fraction levels within the engine were observed to decline from 0.015367293 to 1.13664E-34 for fuel injection timings from 40 BTC to 20 BTC respectively. These findings shed light on the pivotal role of injection timing in enhancing the performance and reducing the emission levels of biodiesel engines.