Dieseling in hydraulic cylinders, or often called the dieseling effect, refers to when hydraulic cylinder oil mixes with air and explodes when pressurized.

Two Primary Causes of Hydraulic Cylinder Dieseling

  1. Negative pressure builds on the rod side of the cylinder when volume fluid demand exceeds the volume of fluid being provided by the pump. This results in air being drawn into the cylinder past the rod seals. Valves perform well at keeping air out, but at times can still allow air in. This occurrence is generally caused by a load control valve that is either faulty or incorrectly adjusted.
  2. Dieseling can also occur if the cylinder chambers are not properly purged during commissioning.

Ways to Avoid Dieseling in Hydraulic Cylinders

  1. Check all working parts of the cylinder via scheduled maintenance. Ensuring proper functionality of the cylinder is paramount to optimal performance and can help address needed repairs before cylinder failure occurs.
  2. Upon commissioning, fill the cylinder with clean hydraulic fluid through the service ports before connecting the hoses. This will help reduce the risk of dieseling.
  3. Cylinders should then be stroked without load several times, being especially mindful not to create pressure at the end-stroke. This process effectively purges air from the cylinder to ensure dieseling will not occur.

Contact us today to learn more about cylinder solutions at Aggressive Hydraulics for all of your business needs. To learn more, send us an email or call us at 866.406.4100.