Patent ID: 6152702
Filing Date: 2000-11-28
Classification: F04B

Abstract:
An apparatus for sensing a parameter of a hydraulic pump, the hydraulic pump includes a housing and an input shaft, the shaft being rotationally driven relative to the housing and being electrically coupled to the housing, the hydraulic pump forming a variable capacitor, comprising:an electrode portion positioned adjacent to the input shaft and being electrically isolated from the housing and input shaft, the electrode portion and the input shaft forming a fixed capacitor, the fixed capacitor being serially connected to the variable capacitor, the capacitive value being indicative of the parameter;power supplying means for supplying electrical energy to the electrode portion;oscillator means for producing a capacitive signal indicative of the capacitance value of the variable capacitor; andcontrolling means for receiving the capacitive signal, for applying a filter to the capacitive signal and responsively producing a filtered capacitive signal, and for determining the parameter of the hydraulic pump as a function of the filtered capacitive signal.