Apparatus and method for determining the output speed of a hydrostatic unit in a hydro-mechanical transmission

摘要

The output speed of a hydrostatic unit in a transmission is determined using a pair of variable reluctance sensors (58, 60) on different gears in the transmission. One sensor (58) is on the hydro unit output (50) of the hydrostatic unit and measures the hydro unit output speed directly. The other sensor (60) is on the transmission planetary carrier (28) of the planetary system (20) and measures the hydro unit output speed indirectly. The hydro unit output speed must be calculated based on the current engine speed and the known transmission gear ratios. Thus the a speed sensor used to determine the hydrostatic unit output speed is not decreased at slow hydrostatic unit output speeds. IMAGE