Abstract: A chassis dynamometer includes a frame, a roll set for engaging the wheels of a motor vehicle and an eddy current brake/inertia simulating unit with a ferrous metal rotor wheel rotatably mounted on the frame and a plurality of stationary field coils. The rotor wheel is in the form of an open ended drum and has a rotational mass which is equal to the trim inertia of the dynamometer, i.e., the base or minimum inertia that the dynamometer is designed to simulate less the roll set inertia. The rotor wheel inertia is preferably within the range of a 70 to 90% of the base or minimum inertia of the dynamometer. A force transducer and a speed encoder provided a measure of the force applied to the roll by the wheel and the speed of the roll, respectively. A controller, in response to the roll speed and force applied to the roll controls the current to the field coils in accordance with a selected simulated inertia and road load for the vehicle.

Abstract: A chassis dynamometer for testing motor vehicles in place includes a frame, at least one roll for engaging the wheel(s) driven by the vehicle engine and an eddy current brake/inertia unit in which the brake rotor is attached to one end of the roll to form an integral structure rotatably supported on the frame at each end of the structure.

Abstract: A chassis dynamometer for testing motor vehicles in place includes a frame, at least one roll for engaging the wheel(s) driven by the vehicle engine and an eddy current brake/inertia unit in which the brake rotor is attached to one end of the roll to form an integral structure rotatably supported on the frame at each end of the structure.

Abstract: A chassis dynamometer includes at least one roll for engaging the driven wheel of a motor vehicle and a power supplying and/or absorbing unit ("PAU") coupled to the roll. Speed and force sensors are also coupled to the roll for providing signals representative of the roll speed and force supplied to or received from the roll, respectively. Vehicle inertia, road load and parasitic loss signals, representative of the vehicle inertia, the vehicle road load and dynamometer parasitic losses, respectively, are also provided. A processing unit, such as a computer, calculates a velocity error signal based on the above signals, representative of the difference between the desired and actual speed of the vehicle. The processing unit further generates a feed-forward signal in response to the speed and inertia signals, representative of at least a portion, and preferably one hundred percent, of the inertial force signal to be simulated by the PAU.

Abstract: A dynamometer for simulating the inertia and road load forces for motor vehicles is described. The dynamometer includes a moveable frame on which is mounted one or more rolls for engaging the driven wheel or wheels of the test vehicle, a power supplying and/or absorbing unit such as an electric motor and one or more mechanical flywheels. The moveable frame is pivotally mounted about the axis of rotation of the rolls. A force transducer is disposed between a point on the moveable frame spaced from the roll axis and a stationary surface for measuring a force which includes as components thereof the roll/wheel interface force and a force associated with the roll, motor and flywheel parasitic losses. A velocity transducer measures the roll speed.

Abstract: A chassis dynamometer includes a frame, a roll set for engaging the wheels of a motor vehicle and an eddy current brake/inertia simulating unit with a rotor having ferrous metal rotor wheel rotatably mounted on the frame and a plurality of stationary field coils. The rotor has a rotational mass within the range of 70 to 90% of the base or minimum inertia of the dynamometer. A force transducer and a speed encoder provide a measure of the force applied to the roll by the wheel and the speed of the roll, respectively. A controller, in response to the roll speed and force applied to the roll controls the current to the field coils in accordance with a selected simulated inertia and road load for the vehicle.

Abstract: A dynamometer for testing engine powered vehicles including an induction motor coupled directly to the vehicle engine or the driven wheels thereof. A computer in response to the engine or wheel speed and the torque applied to or received from the engine or wheels by the motor provides a desired torque signal to a motor power controller to similate the road load and/or vehicle inertial forces encountered by the vehicle during actual operation and to compensate for the parasitic losses of the dynamometer. The motor power controller in turn applies a d.c. voltage to the motor when the desired torque signal is negative to cause the motor to absorb power from the engine or driven wheels and applies an a.c. voltage to the motor when the desired torque signal is positive to cause the motor to supply power to the engine or driven wheels in accordance with the parasitic losses and the road load and/or inertial forces to be simulated by the induction motor.

Abstract: A chassis dynamometer apparatus and method for testing motor vehicles includes at least one roll for engaging the driven wheels of the vehicle. A power supplying and/or absorbing unit such as an electric motor supplies and/or absorbs power from the roll. In addition, a force transducer and speed sensor are coupled to the roll for providing force and speed signals. Signals representative of the desired vehicle inertia, the road load to be simulated, the forces attributable to the parasitic losses and the out-of-loop inertia of the dynamometer and vehicle are also provided. A system controller in response to the above signals controls the power supplying and/or absorbing unit in accordance with: ##EQU1## where: Vd=the desired roll velocity;Fm=the measured force signal associated with the roll;PL=the dynamometer parasitic loss signal;RL=the road load signal;Io=The out-of-loop inertia of the dynamometer and vehicle;Ac=the roll acceleration signal;Iv=the vehicle inertia signal; anddt=the interval of integration.

Abstract: A dynamometer for simulating the inertia and road load forces for motor vehicles is described. The dynamometer includes a moveable frame on which is mounted one or more rolls for engaging the driven wheel or wheels of the test vehicle, a power supplying and/or absorbing unit such as an electric motor and one or more mechanical flywheels. The moveable frame is pivotally mounted about the axis of rotation of the rolls. A force transducer is disposed between a point on the moveable frame spaced from the roll axis and a stationary surface for measuring a force which includes as components thereof the roll/wheel interface force and a force associated with the roll, motor and flywheel parasitic losses. A velocity transducer measures the roll speed.

Abstract: A dynamometer apparatus and a method for testing two and four wheel drive vehicles under simulated road conditions is described. The apparatus includes a front roll and a rear roll for engaging the front and rear wheels of the vehicle. A power supplying and/or absorbing unit such as an electric motor is coupled to each roll. In addition, a force transducer and speed sensor is coupled to each roll for providing signals representative of (a) the forces imported to or received by the rolls from the vehicle wheels minus the forces attributed to the parasitic losses of the rolls and (b) the speed of the rolls. Elements are also included for providing signals representative of the desired vehicle inertia and the forces attributable to the parasitic losses of the rolls. A system controller in response to the above signals controls the power supplying and/or absorbing units in accordance with: ##EQU1## where: V.sub.d =the desired velocity of the driven and driving rolls;F.sub.