Performance of a spark ignition dual-fueled engine using split-injection timing

This study experimentally investigated combinations of dual-fuel mixtures at lean operating conditions. The potential of a dual-fueled engine for reducing emissions and producing acceptable levels of torque and power when compared with a gasoline-fueled engine was evaluated. A Briggs & Stratton engine, Model 130200, was modified for split-timed, manifold injection of two fuels. The injector controls were designed to permit fuel timing with respect to the open position of the intake valve. In each test case, fuel injection was completed and drawn completely into the cylinder before the intake valve closes. It was found that this engine could be operated at a lean condition in such a manner that undesirable combustion phenomena were avoided. Moreover, the feasibility of utilizing timed manifold injection was investigated incorporating the additional feature of a time delay between the gasoline and hydrogen injection.; A total of six experimental configurations were conducted: gasoline, role of injection timing, injection of gasoline with air, the dual fuels of gasoline with propane or gasoline with a hydrogen supplement, and gasoline with variable hydrogen injection timing. At a constant engine speed, equivalence ratio was varied to determine the practical lean misfire limit, and the performance and emissions results were presented as a function of equivalence ratio. Finally, the operating characteristics are discussed for smooth engine operation at constant speed without poor combustion.; The experimental results showed the advantages of the hydrogen supplement at lean operating conditions. Engine performance was improved and emissions lowered. Also, a lower lean misfire limit of &phis; = 0.68 was achieved. Engine power improved approximately 35% when the equivalence ratio, &phis;, was equal to 0.75 and 6 slpm of hydrogen was supplied. At this condition, both the bsCO and the bsHC+bsNO_x level were reduced to 5 g/bhp-hr. These values are much lower than the current CARB regulations of 410 and 12 g/bhp-hr respectively. No time delay between gasoline injection and hydrogen injection is necessary since the performance and emissions remain the same.