Optimization of a low heat rejection engine run on oxy‑hydrogen gas with a biodiesel-diesel blend

Abstract

This experimental investigation examines the combined effects of varying compression ratio (CR) and fuel injection parameters such as fuel injection pressure (FIP) and start of injection (SOI) / injection timing on the performance of a dual-fuel low heat rejection (LHR) engine run on oxy‐hydrogen (HHO) gas with Jatropha biodiesel-diesel blend (JME20) as pilot fuel. The CR is varied from 16.5 to 18.5 in intervals of one, FIP is varied from 220 to 240 bar in intervals of 20 bar,and the SOI is varied from 24.5° to 27.5°CA bTDC in intervals of 1.5°CA. The performance, emission, and combustion characteristics of the dual-fueled LHR engine are studied, based on which the engine operating conditions are optimized. The results reveal that operating the LHR engine with 18.5 CR, 240 bar FIP, and 26°CA bTDC SOI using HHO in dual fuel operation mode with JME20 injected fuel gives better brake thermal efficiency (BTE) (6.6% higher than diesel) and combustion characteristics along with lower carbon monoxide (CO), hydrocarbon (HC), and smoke emissions. In contrast, a slight penalty in nitric oxide (NO) emissions is noticed irrespective of the engine operating conditions.