From an ecological aspect, the hydrogen has all properties to be a very good
fuel for IC engines. However the high combustion speed, as well as the
possibility of backfire, is inconvenient properties of port injection. In
this paper, the influence of the injection timing on the IC engine working
cycle parameters (pressure and temperature) was investigated deeply. The
investigation, of the injection timing influence on the IC engine working
cycle parameters, was performed numerically by application of ANSYS
software. It was observed the geometry of the real engine with added pre
chamber, in order of layer mixture formation and pressure damping, because
of high combustion speed. The results are presented for four cases with
different injection timing and the same spark timing. By earlier injection,
the time for mixing rise as well as the possibility of homogenization and
uniform mixture creation, in pre chamber and cylinder. This claim it is
confirmed on the basis of obtaining pressure and pressure rise gradient,
which are growing with earlier injection, because of hydrogen combustion
characteristics in stoichiometric mixture. The higher pressures as well as
the surface under the diagram are positive from the aspect of the engine
efficiency. However, with the earlier injection, the values of the pressure
rise gradient are higher than for the classic diesel engine. This means that
this phenomena can cause brutal engine work from the aspect of mechanical
stresses. However the value of the maximum pressure is smaller than this in
a diesel engine, this is due to added pre chamber, which has decreased the
compression ratio.