Horiba Instruments, Inc.

Snap-on Technologies, Inc.

Other

Avl North America, Inc.

Automotive Environmental Systems, Inc.

Severino D'Angelo

Clark E Fegraus

Max J Moore

James D Kisner

Robert G Kinne

A dynamometer apparatus having an inside-out motor and a measurement loop which is defined by a load cell. The inside-out motor includes a generally hollow stator shaft through which the motor power cables are festooned. A first set of bearings, located within the measurement loop, support the rotor of the inside-out motor for rotation on the stator shaft. The stator shaft is independently supported on a base structure by a second set of bearings, with the second set of bearings supporting the full weight of the inside-out motor.

Dynamometer having improved sensing configuration

A dynamometer includes a pair of vehicle wheel-engaging rolls coupled through a clutch to a passive power absorption unit which includes a flywheel and an eddy current brake. A lift between the rolls can raise the vehicle wheels out of engagement with the rolls without braking the rolls The lift cooperates with a frame for partially covering and protecting the access one of the vehicle rolls so that, when the lift is raised the vehicle can be driven off the dynamometer substantially without contact of the vehicle wheels with the access roll. The dynamometer is calibrated by using the vehicle wheels to accelerate and decelerate the rolls, with deceleration activating the clutch to decouple the flywheel, which is then used for a coast-down test.

Dynamometer and calibration technique thereof

A chassis dynamometer for simulating the road load and inertia of a vehicle comprised of two axially-movable roller assemblies and a track to guide their axial movement is described. The two independent roller assemblies are free to slide right or left along a track fixed to the lab floor during the vehicle alignment phase that precedes actual testing. Each of said independent roller assemblies includes one or more rollers to engage the driving tire of the vehicle. Said rollers are mechanically coupled to a power absorber and flywheel for simulating the road load and/or inertia of the vehicle. A control system responding to signals from the speed and torque sensors, using a torque split control method, electrically synchronizes the speeds of the two separate assemblies while simulating the selected road load and inertia of the vehicle. Alignment of the vehicle on the dynamometer and positioning of the roller assemblies squarely under the driving tires is achieved by forward and/or reverse rotation of the rollers. A manual or automatic mechanisms locks the individual roller assemblies to the floor track.

Chassis dynamometer employing laterally moving roller assemblies during

A device for restraining the driving tires of a vehicle on a chassis dynamometer which includes sidewall rollers that position themselves automatically as the vehicle approaches the dynamometer and which lock in place before the dynamometer test begins. The restraining rollers are rotatably mounted on one or more carriers that are initially free to move right or left to accommodate the position of the vehicle's tires. When the latter are satisfactorily aligned with respect to the dynamometer rollers, the movable carriers are locked in place, restricting the lateral movement of the driving tires during the test on the dynamometer. The invention is intended particularly for dynamometers in exhaust emission testing facilities, including garages and service stations, where a low-cost, yet robust, vehicle restraint system is desired.

Automatic tire restraints for chassis dynamometers

A suspended large, single roll dynamometer for use in a compact pit. The dynamometer includes a power absorption unit operably coupled to a pair of rolls. The rolls support the driven wheels of a vehicle thereon for rotational movement. A cradle is used to support the power absorption unit, and thus the rolls, within the pit in a manner which does not require significant clearance between the perimeter of the cradle or the rolls and the interior walls of the pit. The components associated with the dynamometer which require periodic access and/or maintenance are further disposed on the power absorption unit so as to be readily physically accessible by an individual without physically entering the pit. The dynamometer apparatus allows the use of a significantly smaller pit than has heretofore been required by conventional dynamometers, thereby providing a significant cost savings in the installation of the pit and allowing the dynamometer apparatus of the present invention to be used in a variety of environments where space limitations would prevent the installation of a conventionally sized pit typically needed for large, single roll dynamometer systems.

Suspended single roll dynamometer

A frictionless bearing chassis dynamometer including a pair of laterally spaced-apart rolls adapted to be engaged and driven by a pair of wheels of a vehicle. A power exchange unit is disposed between the rolls and includes an input shaft fixedly coupled to each of the rolls. The input shaft is supported at its opposite ends by bearing assemblies which each include inner and outer annular bearings and an inner/outer race member disposed therebetween, which forms an outer race for the inner annular bearing and an inner race for the outer annular bearing. Independent bearing motor drive assemblies are coupled to each of the inner/outer race members by independently drivable bearing drive hubs, pulleys and drive belts. Independent bearing motor drive assemblies drive the bearing drive hubs at speeds slightly above and below the rotational speed of the input shaft, to thereby drive the inner/outer race members of each bearing assembly at speeds either slightly below or slightly above the rotational speed of the input shaft. In a preferred embodiment one of the bearing drive hubs is driven slower than the speed of the input shaft while the other bearing drive hub is driven at a speed slightly faster than the input shaft, and the speeds at which the bearing drive hubs are caused to rotate are periodically swapped such that each drive hub is alternately driven at speeds slightly above and below the rotational speed of the input shaft, to thereby cancel frictional forces normally introduced by each of the inner annular bearings.

Frictionless bearing chassis dynamometer

A torque measuring device having dual range load cells is provided featuring high accuracy over a large range of torque measurements. A pair of load cell assemblies act on the torque arm of a dynamometer torque balance. A compliant element is employed to connect the torque arm to a low range load cell assembly and lost motion means are provided by the high level load cell assembly. Low torques imposed on the torque balance cause only the low range load cell to be loaded. The low range load cell assembly is selected to provide high accuracy over the low torque range levels. Once a predetermined threshold torque is applied, the deflection of the compliant element permits the torque arm to engage the high level load cell assembly. Torques beyond the threshold level are determined by summing the measured torques of both load cell assemblies. Several embodiments are described which disclose various means for providing a compliant linkage for the low range load cell assembly and for providing a lost motion coupling for the high range load cell assembly.

Torque measuring device having dual range load cells

An improved mechanical flywheel assembly for a chassis dynamometer. The flywheel assembly includes a plurality of flywheels journalled to a stationary shaft located within a cylindrically-shaped drum that is directly coupled to the rollers of the dynamometer so that the drum rotates at the speed of the rollers. Each of the flywheels has an air-actuated clutch mechanism secured around the periphery of the flywheel so that upon actuation, the clutch mechanism expands radially sufficiently to engage the inner wall of the drum and thereby cause the associated flywheel to rotate with the drum. Means are disclosed for controlling the selective actuation of the various clutch mechanisms to thereby selectively control which of the various flywheels are engaged.

Flywheel assembly for dynamometers

A vehicle force measurement system for determining the force output of a vehicle independent of the radius dimensions of the driving wheels of the vehicle. A fifth wheel is utilized to provide an accurate vehicle speed reading. Torque and RPM sensors mounted to the driving wheels of the vehicle are used to determine the total power output of the vehicle and the total force output of the vehicle is determined by dividing the total power output by the speed signal from the fifth wheel.

Vehicle force measurement system

A dynamometer system for simulating road load and vehicle inertia forces for testing vehicles in place. The system includes a DC motor power absorption unit (PAU) and a microcomputer based system controller for controlling both the road load and inertia forces simulated by the PAU. A non-declutchable flywheel is used to simulate mechanically a constant amount of inertia to minimize the power requirements of the PAU. The control scheme is designed to implement the classic dynamometer control expression (F=A+Bv+Cv.sup.2 +I dv/dt) in a novel manner with a minimum amount of delay time. The microcomputer is provided with the following measured functions: speed, acceleration, and a torque signal. The total force output to be simulated by the PAU is determined by first calculating the actual force output of the vehicle, and then determining the percentage of the total force output that should be assigned to the PAU. In calculating the total force output of the vehicle, the inertia outside the torque loop is accurately accounted for, thus permitting the torque transducer to be placed adjacent the PAU. In addition, the force output control signal applied to the PAU is corrected by an inertia error function to insure that the actual inertia force simulated by the PAU corresponds to the desired inertia value. A novel method of accurately converting the frequency signal from the speed sensor to a parallel digital signal without introducing an excessive time delay is also disclosed.

Dynamometer

Prior art electromechanical inertia and road load simulators as applied in dynamometers measure speed and acceleration, then compute and control torque--a relatively slow and inaccurate operation. This invention measures torque, then computes and controls acceleration and speed--a fundamentally different approach which provides faster action, more accurate simulation and closer repeatability. The simulator described herein includes and is controlled by a computer which is provided with inputs from a torque transducer, a speed encoder and operator entered digital signals. The computer then makes accurate and rapid computations of vehicle inertia, road load forces and generates an electrical speed control signal. This signal is provided to a controller for a power absorber, e.g., a direct current power controller which drives a direct current motor. The power absorber such as the motor is mechanically coupled to the vehicle engine or a rotating roll upon which a test vehicle drive wheel rests. Effects of cooling due to vehicle velocity may be provided by a cooling fan which is mounted in front of the test vehicle and which is hydraulically coupled to the rotating roll.

Growing community of inventors

Laguna Beach, CA, United States of America

Severino D'Angelo