Prediction of hydrogen-heavy fuel combustion process with water addition in an adapted low speed two stroke diesel engine: Performance improvement

Abstract

Despite their high thermal efficiency (>50%), large two-stroke (2 T) diesel engines burning very cheap heavy fuel oil (HFO) produce a high level of carbon dioxide (CO2). To achieve the low emission levels of greenhouse gases (GHG) that will be imposed by future legislation, the use of hydrogen (H2) as fuel in 2 T diesel engines is a viable option for reducing or almost eliminate CO2 emissions. In this work, from experimental data and system modelling, an analysis of dual combustion is carried out considering different strategies to supply H2 to the engine and for different H2 fractions in energy basis. Previously, a complete thermodynamic model of a 2 T diesel engine with an innovative scavenging model is developed and validated. The most important drawbacks of this type of engines are controlled in this work using dual combustion and water injection, reducing nitrogen oxides emissions (NOx), self-ignition and combustion knocking. The results show that the developed model matches engine performance data in diesel mode, achieving a higher efficiency and mean effective pressure (MEP) in hydrogen mode of 53% and 14.62 bar respectively.