Study on Hydrogen-Assist Diesel Combustion (2st Report, Investigation of Low Temperature Combustion with Hydrogen Addition to Intake Gas and High Rate EGR)

The present study experimentally investigated the performance and emission characteristics of the diesel engine with small amount of hydrogen added to the intake air at high EGR rate. The EGR rate, the diesel-fuel injection timing, and the hydrogen fraction in the intake mixture were varied while the available heat produced by diesel fuel and hydrogen per second was kept constant under high load condition in naturally-aspirated diesel engines. In the case of the diesel-fuel injection timing of 2 deg.BTDC with 3.9 vol% hydrogen addition, the smoke emission value was almost 0 %, NO emission was low, the cyclic variation was low, and the maximum rate of incylinder pressure rise was acceptable under a nearly stoichiometric condition without sacrificing indicated thermal efficiency.