Research of combustion process was made in a specially designed research engine in which simultaneous pressure measurement and Schlieren visualization of the combustion process were possible. Pressure as well as the timing of each picture was recorded by the data acquisition computer system. The whole operation of the experimental apparatus is also controlled by PC computer connected to a special control unit. Combustion studies were focused on the comparison of classical spark ignition system to the jet ignition, initiated by a specially produced Pulsed Jet Combustion (PJC). Comparison of the flame propagation velocity and variation of the pressure in the chamber for different ignition systems and different equivalence ratio of combustible mixtures were made. It was found that under all experimental conditions jet ignition is superior over conventional spark ignition system. Comparison of pollutants emission was also made.