Combustion by Pulsed Jet Plumes - Key to Controlled Combustion Engines

Pulsed Jet Combustion (PJC) is introduced here as a key element for engines where the progress of combustion is interactively controlled by a microprocessor system. Practical realization of PJC presented here involves the use of an 18 mm plug containing a cavity, where a rich mixture is ignited by a conventional spark discharge, closed by a tip with a suitable orifice to form the effluent stream. Its performance is determined by tests carried out in a constant volume vessel, simulating the enclosure of a CFR engine at 60 CAD with compression ratio of 7:1, using propane/air mixtures at equivalence ratios of an order of 0.6, in comparison to that of a flame traversing the charge, a so-called FTC mode, upon ignition by standard spark discharge under identical geometrical and initial thermochemical conditions. The results demonstrate the superiority of PJC for executing the exothermic process of combustion in a lean burn engine.