Patent ID: 6247357
Filing Date: 2001-06-19
Classification: G01L,G01M

Abstract:
In a dynamometer having a minimum, maximum and trim rotational inertia for simulating the inertial and road load forces which a motor vehicle would experience during operation on a road bed, the combination comprising:a) a frame;b) at least one roll rotatably mounted on the frame for engaging a driven wheel of the vehicle;c) a power absorbing and inertia simulating unit comprising an electrically and magnetically conducting rotor wheel rotatably mounted on the frame and permanently coupled to the roll for rotation therewith and at least one stationary field coil positioned adjacent the rotor wheel for inducing eddy currents in the rotor wheel during rotation of the roll to apply a braking torque to the roll, the rotor wheel being in the form of a drum open at one end with a hollow braking section extending axially from the open end to a web section extending radially inwardly to a hub mounted on the shaft, the rotational inertia of the rotor wheel being equal to the trim inertia and within a range of 50% to 90% of the minimum inertia of the dynamometer;d) force sensing means coupled between the roll and the frame for providing a measure of the force applied to the vehicle wheel minus the force attributable to the dynamometer parasitic losses;e) speed sensing means for providing a measure of the roll speed; andf) control means responsive to the roll speed and the force applied to the vehicle wheel for controlling the current to the field coil to absorb power from the roll so that the force applied to the vehicle wheel is proportional to a force associated with a selected simulated inertia and road load for the vehicle.