Comprehensive review of combustion, performance and emissions characteristics of a compression ignition engine fueled with hydroprocessed renewable diesel

Abstract

Rapid depletion of fossil fuel reserves and mandate to meet stringent emission norms including green house gas (GHG) emissions for advanced compression ignition (CI) engines are the main rationale behind alternative fuel research. In a quest of searching an alternative to the petroleum-based diesel fuels from various renewable feed-stocks such as animal fats, non-edible vegetable oils or microalgae oil, hydroprocessed renewable diesel (HRD) is perceived as one of the potential drop-in alternative fuel for a CI engines. HRD possesses most of the physico-chemical properties similar to that of petro-diesel (ASTM D975 or EN590). This paper critically examines the HRD fuel (neat as well as blended with petro-diesel) against petro-diesel with respect to combustion, performance, nitrogen oxides (NOx) and particulate matter (PM) emissions characteristics of a CI engine. It emerged from the literature review that HRD fueled engine results in marginally lower in-cylinder pressure peak, significant reduction in heat release rate (HRR) and specific fuel consumption, develops similar to better brake power and shows around 10% improvement in brake thermal efficiency as compared to petro-diesel. HRD fueled engine reduces the mass based PM emissions, solid particle numbers (PN) and size than diesel, while NOx trend is inconsistent for different types of engine technology, test cycles, type of fuel injection system etc. But, most of the reported results on NOx emissions show reducing trend for HRD fueled engine. Overall it may be concluded that HRD is a promising alternative fuel for CI engines, which is renewable and can be developed as a sustainable alternative to petro-diesel in long term scenario.