Abstract
The present invention relates generally to hydraulic lift systems and, more specifically, to hydraulic pressure relief systems and methods on material handling vehicles. The hydraulic control system includes a pump having a pump outlet in fluid communication with a supply passage, a reservoir in fluid communication with a return passage, one or more hydraulic actuators configured to raise and lower a fork assembly attached to a mast of the material handling vehicle, a variable pressure relief valve configured to selectively provide fluid communication from the supply passage to the reservoir, and a controller in communication with the variable pressure relief valve and a pressure sensor configured to measure a pressure in the supply passage.