ABSTRACT
Evaluating the performance enhancement of a diesel engine through the addition of
Oxy-hydrogen (HHO) gas generated through water electrolysis has been
investigated by several researchers. The outcomes were claimed to be very
promising. It is thought however that the results need more investigation. This study
is carried out to evaluate the influence of adding HHO gas into the inlet air on the
performance of a direct injection diesel engine. The experimental work is carried out
under constant speed with varying load and amount of introduced HHO generated
through water electrolysis. In this work the results contrary to many publication
showed that, the thermal efficiency increases only at low loads and the brake
specific fuel consumption consequently decreases at low loads too (up to 23% of
maximum load). Using oxyhydrogen; the maximum engine power decreases with
increasing electrolyte concentration. The maximum reduction in maximum power
was (3.8 % to 7.6). An explanation for the results was attempted.