Fuel and ignition control methodologies for engines with articulated connecting rods

Abstract

In this work fuel and ignition control techniques are developed for articulated rod, largebore, two-stroke, natural-gas-fuelled engines. A Cooper-Bessemer GMV-4TF engine is utilized for the experimental investigation. Due to the articulation of the connecting rods, the even bank cylinders have different piston position and port opening profiles and different compression ratios than the odd bank cylinders. Additionally, due to the mechanical design of the engine, ignition and top dead centre (TDC) for the cylinders are not evenly spaced. The non-symmetric timing and articulated geometry result in different gas flow characteristics for each cylinder bank. These differences result in increased NOX emissions of the even cylinder bank compared with those of the odd bank. Results of engine testing have demonstrated that this difference can be compensated for through bank specific fuel and ignition control. Two separate control techniques were utilized for compensation. The first resulted in decreased fuel consumption at a constant NOX level, and the second produced reductions in NOX emissions at a constant fuel consumption.