Evaluating gaseous fuel admission valve operability

摘要

A method of evaluating operability of gaseous fuel admission valves (58) of a dual fuel internal combustion engine (100) is disclosed that is performed, for example, during the transition from liquid to gaseous fuel. The method comprises operating (step 312) the dual fuel internal combustion engine (100) on liquid fuel; supplying (step 354) gaseous fuel to the gaseous fuel admission valves (58) at a pressure above an intake manifold air pressure thereby setting a differential gas pressure across the gaseous fuel admission valves (58); operating (step 356) the gaseous fuel admission valves (58) to add gaseous fuel to intake air while operating the dual fuel internal combustion engine (100) primarily on liquid fuel; measuring (step 360), for each cylinder of the plurality of cylinders a combustion process parameters such as the cylinder pressure; and evaluating (step 362) operability of the gaseous fuel admission valves (58) based on the measured combustion process parameters. Deviating gaseous fuel amounts may result in cylinder-specifically deviating combustion process parameters, allowing to identify malfunctioning gaseous fuel admission valves.