| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine control device for a hydraulic type construction machine, capable of aiming at low fuel consumption and noise, while the resonance of an engine is being prevented. SOLUTION: A controller for controlling the revolution of an engine, is provided with an auto-idle command outputting means outputting a first two speed revolution command to the engine, capable of setting engine revolutions at its low revolution N1 higher than that of the maximum resonance point, taking place after prescribed time has elapsed since an operation lever was entirely set at a neutral position, and also outputting a second low revolution command to the engine, capable of setting the engine revolution its low revolution N2 at a place close to an antiresonace point lower than that of the maximum resonance point after the prescribed time has elapsed since the first command was outputted. This constitution thereby enables the engine under a second low speed rotating condition to surely avoid resonating and also enables fuel consumption and noise to be effectively lowered sufficiently, because engine revolutions are so set as to be low in vibration than that of the maximum resonance point.
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