ENGINE CONTROL SYSTEM FOR WORK MACHINE

Provided is an engine control system that is used for a working machine and capable of properly measuring the sulfur content of an exhaust gas as sulfur is detrimental to normal functioning of an exhaust gas aftertreatment device and reducing the degree of sulfur poisoning of the exhaust gas aftertreatment device. Each time a key switch (46) is turned ON to start an engine (1), the engine control system compares a remaining fuel amount memorized at the last stop of the engine (1) and a remaining fuel amount detected at the current start of the engine (1). The engine control system performs a sulfur concentration measurement process only when the remaining fuel amount is increased. In this process, the engine control system exercises fixed control to forcibly set a revolution speed of the engine (1) to a target revolution speed Na appropriate for measuring the concentration of sulfur. When the temperature of the exhaust gas is within a predetermined temperature range Texa-Texb appropriate for measuring the sulfur concentration and a target time Ta elapses, the engine control system determines whether the sulfur concentration is not lower than a threshold value. If the sulfur concentration is not lower than the threshold value, the engine control system activates an alarm display device (42).