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Hydrogen can be produced by electrolyzation with renewable electricity and the combustion products of hydrogen mixture include no CO, CO2 and hydrocarbons. In this study, engine performance with hydrogen / diesel dual fuel (hydrogen DDF) operation in a multi-cylinder diesel engine is investigated due to clarify advantages and disadvantages of hydrogen DDF operation. Hydrogen DDF operation under several brake power conditions are evaluated by changing a rate of hydrogen to total input energy (H2 rate). As H2 rate is increased, an amount of diesel fuel is decreased to keep a given torque constant. When the hydrogen DDF engine is operated with EGR, Exhaust gas components including carbon are improved or suppressed to same level as conventional diesel combustion. In addition, brake thermal efficiency is improved to 40% by increase in H2 rate that advances combustion phasing under higher power condition. On the other hand, NOx emission is much higher than one of conventional diesel engine.

The tasks to improve diesel emissions and fuel consumption must be accomplished with urgency. However, due to the trade-off relationship between NOx emissions, soot emissions and fuel consumption, clean diesel combustion should be achieved by both innovative combustion and fuel technologies. The objective of this study is to extend the clean diesel combustion operating range (Engine-out emission: NOx ≺ 0.2 g/kWh, Soot ≺ 0.02 g/kWh). In this study, performance of a single-cylinder test engine equipped with a hydraulic valve actuation system and an ultra-high pressure fuel injection system was investigated. Also evaluated, were the effects of fuel properties such as auto-ignitability, volatility and aromatic hydrocarbon components, on combustion performance. The results show that applying a high EGR (Exhaust gas recirculation) rate can significantly reduce NOx emission with an increase in soot emission.

Temperature distributions in n-heptane and n-tridecane sprays were measured by the planar laser induced fluorescence (PLIF) method. The spray was formed by injecting fuel into high temperature and high pressure ambient, which was formed by compression of rapid compression and expansion machine (RCEM). In this PLIF method, acetone was used as a fluorescence tracer and was mixed with ambient gas. The fluorescence tracer was excited by 266 nm (the 4th harmonic of a Nd:YAG laser). The fluorescence intensity was measured by an ICCD camera. The temperature and concentration were estimated based on temperature dependency of the fluorescence intensity and the assumption of adiabatic mixing. Based on the measurement results, The difference of mixture distributions in n-heptane and n-tridecane sprays are discussed.