Evaluation of tractor biodegradable hydraulic fluids on the basis of hydraulic pump wear

Two types of biodegradable hydraulic fluids (HEES and HEPR) with the mineral oil-based hydraulic fluid (HV) were compared. The tests were performed using a test bench. During the tests with a tractor hydraulic pump, the fluids were loaded by a cyclic pressure load. The tests of fluids were evaluated on the basis of wear of the pump. Evaluation parameters were the flow characteristics of the pump and the cleanliness level of tested fluids. The temperature of the fluid under which the test was performed was measured in real operating conditions of the Zetor Forterra 11441 tractor. It is possible to state upon the test results that the mineral oil-based fluid was classified in the first place, the biodegradable fluid of the HEPR type in the second place, and the biodegradable fluid of the HEES type received the last position.