Method for testing a hydrostatic transmission

摘要

A method for testing a transmission of a vehicle, the transmission including a hydrostatic unit installed on the vehicle. The method includes calculating an actual value of a parameter which is indicative of the volumetric efficiency of the hydrostatic unit, in a working condition. The method also includes determining an expected value of the parameter in the working condition. The actual value is comparable with the expected value in order to evaluate how the hydrostatic unit is working.

主权项

1. A method for testing a hydrostatic transmission of a vehicle, the hydrostatic transmission comprising a hydrostatic unit installed on the vehicle, the method comprising the following steps:
calculating an actual value (Qa) of a parameter (Q) which is indicative of the volumetric efficiency of the hydrostatic unit, in a working condition, wherein the parameter (Q) is the ratio between a value (ηv) of the volumetric efficiency of the hydrostatic unit determined when a clutch of the vehicle is at least partially engaged and a further value (ηv0) of the volumetric efficiency of the hydrostatic unit determined when the clutch is disengaged, wherein the further value (ηv0) is determined from the rotational speeds (nE0; nHST0) respectively of a first component associated with an input of the hydrostatic unit and of a second component associated with an output of the hydrostatic unit, measured during a first measuring step in which the vehicle is stationary and its clutch is disengaged, and wherein the value (ηv) is determined from the rotational speeds (nE; nHST) of the first component and of the second component, measured during a second measuring step in which the clutch is at least partially engaged; and determining an expected value (QED; QEE) of the parameter (Q) in the working condition, the actual value (Qa) being comparable with the expected value (QED; QEE) in order to evaluate how the hydrostatic unit is working.