Development of a low-NOx truck hydrogen engine with high specific power output

The charged hydrogen engine with internal mixture formation as part of the HYPASSE (Hydrogen Powered Automobiles using Seasonal and weekly Surplus of Electricity) project will be presented. With direct hydrogen injection it is possible to solve the problems of hydrogen engines with external mixture formation. Those problems are knocking, glow ignition during compression stroke and backfiring past the intake valve. With the internal mixture formation system, the volumetric efficiency and the power output is equal to that of a diesel engine. To obtain low NOx emissions it is necessary to operate the H-2-engine at excess air ratios lambda greater than or equal to 2 by means of turbocharging. The discrepancy between late high-pressure injection together with diffusion flame propagation and early injection, i.e. to obtain a more homogeneous internal mixture formation, is studied by operating a single cylinder research engine. (C) 1997 International Association for Hydrogen Energy.