Dieseling of the hydraulic cylinders. Review from professionals | Magister Hydraulics

Hydraulic Cylinder Dieseling meaning!

Hydraulic system of any type and complexity, involving hydraulic cylinders within always has an exposure for dieseling effect. Such issue can be very dangerous and hazardous. Therefore it is significant to be aware of the potential liability that hydraulic system can cause with the dieseling trouble.

The word dieseling actually has nothing to do with diesel as petroleum product. However hydraulic dieseling refers to the combustion process in the diesel engine, where piston compresses fuel with mixed air and spark ignites the mix under the pressure. For combustion engine, a spark is needed that can combust the fuel mix. However, pressure itself would be enough to cause combustion in the engine. Exactly the same effect applies in hydraulic system. We will cover below on how dieseling effect occurs in hydraulic cylinders.

CAUSES of dieseling in Hydraulic Cylinders

At times, when the double-acting hydraulic cylinders extend or retract, the volume of hydraulic oil required over the rod side is greater than that has been supplied from the hydraulic pump on the opposite side port. If this occurs, it creates negative pressure over the cylinder rod. The negative pressure sucks the air past from the seals of the rod as well as in the cylinder. Therefore, when a contaminated oil-air mixture in the cylinder gets pressurized over the new stroke, it may combust or explode. This effect destroys hydraulic cylinder seals and can crack or deform the cylinder tubing.

How to avoid hydraulic cylinder dieseling?

To avoid dieseling, we need to tackle the faults that become the reason for air to penetrate into a hydraulic cylinder.

First, ensure that both chambers of hydraulic cylinder are completely emptied from the air in commissioning. If not, potential air entrance will automatically lead towards dieseling effect.

Second, the defective float valve is another reason that is due to air contamination. This occurs in equipment such as hydraulic excavators. In this application the float valve should consider the boom to be brought down quickly in its own load and a cylinder to likewise be retracted simultaneously. The valve should permit the liquid from the cylinder piston to be guided with rod side priority instead of sent directly to the tank. If a valve does not function properly or incorrectly set, you finish up with the negative pressure, so with dieseling.

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