Large Turbocharged Slow Running Two-Stroke Diesel Engine and Method for Obtaining Characteristics of a Butterfly Valve in a large Two-Stroke Diesel Engine

A method for obtaining the characteristics of a nonlinear valve ( 34, 44) in an exhaust bypass of a large turbocharged slow running two-stroke diesel engine ( 1) that is used for regulating the flow in the exhaust bypass. The exhaust bypass controllably allows exhaust gas to bypass the turbine (17) of the turbocharger (16). The method comprises running the engine ( 1) , and while running the engine, opening the non-linear valve (34,44) in small increments from a completely closed position to a completely open position and measuring the scavenge air pressure or other suitable engine operating parameter at each position of the non-linear flow regulation valve (34, 44), and/or closing the non-linear flow regulation valve (34,44) in small increments from a completely open position to a completely closed position and measuring the scavenge air pressure at each position of the butterfly valve. Then, recording the valve positions and the associated measured scavenge air pressures, and storing the recorded positions and associated scavenge air pressures.