Hydrogen rich gases combustion in the IC engine

Experimental results of combusting three different syngases in an internal combustion (IC) spark ignition engine are presented in this paper. The syngases used for tests varied each from the other with hydrogen content, which was of 10,15 and 60%. Other combustible gases as CO and CH4 were also changed. Thus, the lower heating value of the syngases was of 2.7, 4.6 and 17.2 MJ/nm3, respectively. Combustion tests were performed at stoichiometric ratio of syngas-air mixture, with variable spark timing and constant compression ratio of 10. On the basis of in-cylinder combustion pressure histories the indicated mean effective pressure (IMEP) was computed and presented versus spark timing and vs location of the middle combustion phase expressed by the 50% of mass fraction burned (MFB). Additionally, the 0-10% MFB and 10-90% MFB were also determined. Furthermore, the paper contains theoretical determination of the three fuel quantities, which can affect combustion duration and heat release rate during burning the syngases in the IC engine. They are as follows: laminar flame speed, ignition delay and adiabatic flame temperature. Final results does not show satisfactory correlation between LFS computed at NTP and real combustion phasing. Furthermore, both long combustion duration and long 0-10% MFB leading to unstable combustion were observed for the syngas with the lowest LHV of 2.7 MJ/nm3.