Reasons for Uneven Rotating Speed of Perkins Diesel Generator Set

Rotating speed unevenness is a problem that many Perkins diesel generator set customers are very concerned about. Let's first take a look at the performance of rotating speed unevenness, and then follow Starlight to understand several common causes of rotating speed unevenness.

Perkins diesel engine has two manifestations of uneven rotational speed: one is a large amplitude swing, with a clear and recognizable sound, commonly referred to as "panting" or "traveling block"; The other is that the rotational speed fluctuates within a small range, making the sound difficult to distinguish, and is prone to occur at low rotational speeds, which can cause the diesel engine to stall.

The reason for the uneven rotational speed of the Perkins diesel engine is mostly due to the abnormal resistance of the moving parts of the fuel injection pump and governor, and the sluggish response of the governor. There are many specific factors, generally including the following 8 points.

(1) Individual cylinders do not work. If one cylinder of a multi cylinder diesel engine does not work, its operation will not be smooth and the explosion noise will not be uniform. The cylinder shutdown method can be used to find out which cylinder is not on fire.

(2) The fuel supply is uneven. When the diesel engine is running, the cylinders with more fuel supply work strongly, with a knocking sound and black smoke. Cylinders with low fuel supply work weakly or even do not work. Eventually, the rotational speed of the Perkins diesel engine is uneven.

(3) The diesel fuel supply system contains air and moisture, and the fuel transfer pump is not working properly.

(4) If the fuel supply time is too early, it is easy to generate high-speed "traveling block", but at low speeds, it is stable.

(5) The gear rod or shift fork rod of the fuel injection pump is not smooth, resulting in a decrease in the sensitivity of the governor.

(6) The fuel injection nozzle burns or drips oil.

(7) Incorrect valve clearance.

(8) The diesel engine speed is unstable due to untimely speed regulation. When the wear clearance at various connections within the governor increases, moving parts such as steel balls or air hammers become jammed, and the governor spring fails, the governor must overcome the resistance or first eliminate the clearance before moving the adjusting gear rod or shift fork rod to increase or decrease the oil supply. Due to untimely speed regulation, the rotational speed fluctuates from high to low. For models such as 135 or 105 that use a combined fuel injection pump, by opening the fuel injection pump side cover, you can see that the adjusting rod moves repeatedly and regularly. If the Perkins diesel engine is traveling slightly, you can see that the pull rod will shake at this time.

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