Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M17/00—Testing of vehicles
  • G01M17/007—Wheeled or endless-tracked vehicles
  • G01M17/0072—Wheeled or endless-tracked vehicles the wheels of the vehicle co-operating with rotatable rolls
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M17/00—Testing of vehicles
  • G01M17/007—Wheeled or endless-tracked vehicles
  • G01M17/0072—Wheeled or endless-tracked vehicles the wheels of the vehicle co-operating with rotatable rolls
  • G01M17/0074—Details, e.g. roller construction, vehicle restraining devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M17/00—Testing of vehicles
  • G01M17/007—Wheeled or endless-tracked vehicles
  • G01M17/0072—Wheeled or endless-tracked vehicles the wheels of the vehicle co-operating with rotatable rolls
  • G01M17/0076—Two-wheeled vehicles

Definitions

• the invention relates to a dynamometer and test method for simulating road conditions, for testing a vehicle having at least two drive wheels, and more particularly to a dynamometer having rollers for engagement with the vehicle wheels, and that is relatively compact, inexpensive and portable. Further, the invention relates to an apparatus and method permitting simulation of straight-line and curved driving conditions. The invention may also be adapted for use with a vehicle having a single drive wheel such as a motorcycle.
• Emissions testing and maintenance of vehicles is effective if vehicle road conditions may be effectively simulated. This is typically accomplished by means of a roller arrangement for contact with the drive wheels of the vehicle, with the rollers being operatively linked to a dynamometer for placing a controlled load on the rollers.
• the load quantum will be a function of the rotational speed of the rollers (i.e. the simulated vehicle speed), simulated and real frictional losses, and a polynomial equation representing wind resistance of the particular vehicle.
• the dynamometer simulates two aspects of vehicle performance, namely inertia and drag. Inertia in this case is governed by the weight of the vehicle and the equivalent of rotating masses of the vehicle, with the device thus simulating inertia based on this factor. Drag is simulated by the dynamometer applying a resistance to the rollers, governed by the actual wheel speed of the vehicle and the wind resistance factor. Inertial energy may be provided by means of a fly wheel as well as simulation by other means
• dynamometer resistance is provided by a braking mechanism such as an electric motor, water brake, etc
• a braking mechanism such as an electric motor, water brake, etc
• other resistance-generating means may be employed and the present invention is not limited to the use of any particular braking means
• An object of the present invention is to provide an improved roller dynamometer and testing method for simulating road conditions for testing a vehicle.
• a further object is to provide a roller dynamometer comprising multiple dynamometer assemblies not mechanically linked to each other for common rotational movement, each dynamometer assembly for contact with an individual vehicle wheel, with the effective width of the roller dynamometer being variable by changing the distance between the individual units.
• a further object is to provide a roller dynamometer that may be used with any conventional vehicle, and which has the capacity to simulate either straight-line or curved driving conditions.
• a further object is to provide a relatively lightweight and portable roller dynamometer that may be conveniently transported to a testing site.
• the present invention comprises in one aspect a roller dynamometer assembly for simulating road conditions for a vehicle having at least two drive wheels, comprising: first and second dynamometer carriages; carriage support means associated with at least one and preferably both carriages for supporting one or both carriages and permitting the carriage to be moved relative to a substrate; first and second rollers not mechanically linked with each other rotatably mounted to respective carriages for supporting and rotatably contacting a corresponding vehicle wheel; first and second dynamometers (conveniently comprising electric motors) each having speed and torque sensing means and engaged to a corresponding roller for applying a load to said corresponding roller whereby road conditions are simulated on a vehicle engaged with said apparatus.
• the carriage support means which preferably comprise roller means such as an array of linear bearings, permit independent lateral (relative to the vehicle) movement of the carriages. This permits adjustment of the carriage spacing to accommodate different vehicles (permitting the use of relatively compact rollers) and roller self-centering on the vehicle wheels when the device is in use. The latter is particularly useful when the device simulates curved driving conditions.
• the rollers may also have a stepped portion at each of the opposed ends to serve as a wheel stop and fly wheel.
• the apparatus further conveniently incorporates a rotary mount for supporting and mounting each dynamometer to corresponding carriages for limited rotational movement relative to said carriage.
• the rotary mount preferably comprises first and second concentric members, such as a disc and trunnion bearing arrangement, engaged to said dynamometer and carriage respectively for rotation relative to each other.
• the dynamometers are in communication with a controller, the controller receiving wheel speed and torque information from each of the dynamometers.
• the controller includes processing means for comparing rotary speed differences between the first and second dynamometers and torque control means for controlling the torque applied by at least one and preferably both of the dynamometers to substantially equalize the respective rotary speeds of said rollers.
• the control means preferably directs a faster spinning dynamometer to apply a greater amount of power absorption to its corresponding roller, relative to the slower spinning dynamometer.
• the controller may include total power absorption calculation means, wherein the total power absorbed amongst all dynamometers is calculated as a function of the mass of the vehicle, the speed and acceleration of each roller, and a value associated with the vehicle aerodynamic and frictional losses and frictional losses within the dynamometers.
• the torque control means further permits control of one or both dynamometers to apply a controlled unequal rotary speed of the respective rollers to simulate a curved driving condition.
• the invention comprises a roller dynamometer vehicle testing assembly for simulating road conditions for a vehicle, comprising: at least one roller mounted to a frame for supporting and rotatably contacting a vehicle wheel; a dynamometer engaged to the roller for applying a load to the roller whereby road conditions are simulated on the vehicle engaged to the apparatus; a rotary mount for engaging and supporting dynamometer onto the frame for rotational movement relative to the frame, the rotary mount comprising first and second concentric members engaged to said dynamometer and carriage respectively.
• the rotary mount is conveniently of the type characterized above.
• the apparatus is conveniently provided with rollers for contact with the drive wheels of the test vehicle.
• the invention comprises a roller dynamometer for simulating road conditions for a vehicle having at least two drive wheels, comprising first and second roller dynamometer assemblies for independent engagement with corresponding drive wheels, each roller dynamometer assembly comprising at least one roller engaged to a corresponding dynamometer, the first and second dynamometer assemblies for independent rotation of the respective rollers relative to each other and each having rotary speed and detection means and power absorption means, and a control unit for receiving rotary speed and torque information from said dynamometers and having a logic circuit for comparing and measuring any speed differences and controlling one and preferably both dynamometers in response to speed differences
• the logic circuit controller controls the power absorption means of the first and second dynamometers to achieve either straight-line or curved driving simulation
• the controller conveniently includes total power absorption calculation means, wherein the total power absorbed amongst all dynamometers is calculated as a function of the mass of the vehicle, the speed and acceleration of each roller, and a value associated with the vehicle aerodynamic and frictional losses and frictional losses within the dynamometer
• the invention comprises a method for simulating road conditions for a vehicle, comprising the steps of providing first and second independent roller dynamometer assemblies each associated with torque and rotational speed sensors, the first and second assemblies being associated with a controller for receiving speed and torque information from each dynamometer assembly and independently controlling the resistance applied thereby; supporting at least two vehicle drive wheels on corresponding first and second roller dynamometer assemblies; driving the drive wheels with the test vehicle; independently measuring the speed and torque of the two drive wheels; independently controlling at least one and preferably both roller dynamometer assemblies to control the rotary speed thereof.
• a further step may comprise measuring the total power output of the vehicle with an algorithm that calculates total dynamometer power absorption, wherein the total power absorbed amongst all dynamometers is calculated as a function of the mass of the vehicle, the speed and acceleration of each roller, and a value associated with the vehicle aerodynamic and frictional losses and frictional losses within the dynamometer.
• the rollers preferably comprise in any of the above devices and methods a generally hourglass configuration for self-centering of the vehicle wheels.
• Figure 1 is a plan view of one embodiment of the present invention
• Figure 2 is a side elevational view of a portion of the apparatus as shown in Figure 1
• Figure 2a is an end elevational view of Figure 1
• Figure 3 is a plan view of an individual roller unit for use in accordance with the present invention
• Figure 4 is a plan view of a further embodiment of a roller carriage
• Figure 5 is a side view of Figure 4
• Figure 6 is a perspective view of the apparatus in use
• Figure 7 is a block diagram showing the operation of the invention.
• the apparatus 10 includes first and second identical carriages 24, one of which is illustrated herein.
• the respective carriages are positioned under the left and right vehicle wheels when a vehicle is engaged for testing with the device.
• the carriages each support individual rollers, described below, for engagement with the vehicle wheels, and dynamometers mating with the rollers.
• the carriages are conveniently positioned on a smooth, level, hard surface 15.
• Each carriage may be moved laterally (relative to the vehicle) on the surface by roller means associated with each carriage, such as a linear bearing array 30 (shown in Figure 2) on the lower face of the carriages.
• the roller means further permit the carriages to roll laterally while bearing the vehicle, in order to accommodate the self-centering of the carriage rollers.
• each carriage 24 comprises a generally rectangular carriage frame 32 composed of side frame members 34, end frame members 36, the whole being bisected by paired transverse frame members 40 and 42 to form first and second rectangular carriage portions 32a and 32b.
• the first carriage portion 32a supports the rollers, described below, and the second carriage portion 32b supports the dynamometer, described below.
• End and transverse frame members 36 and 40 of the first carriage portion 32a each support a pair of axle bushings 50 for rotatably supporting the rollers 54.
• Roller axles 56 associated with each of the rollers are rotatably joumalled within the axle bushings.
• the end and transverse members 36 and 42 of the second carriage portion 32b support dynamometer mounts 60, for rotatably mounting a dynamometer 46 to the carriage. The dynamometer and mounts will be described in greater detail below.
• the first carriage portion 32a supports a pair of spaced-apart rollers 54 in parallel orientation for supporting and rotationally engaging a driven wheel of a vehicle.
• one of the rollers 54 of the pair is engaged to a dynamometer.
• the other roller freewheels.
• Each carriage thus supports a single dynamometer, comprising a power absorption unit ("PAU") associated with a single vehicle drive wheel.
• PAU power absorption unit
• the rollers can be sized to accommodate paired drive wheels of the type found in trucks and busses.
• the dynamometer mounts 60 each comprise a disc 62 fixedly mounted to the carriage portion 32b for engagement with a corresponding end face 64 of the dynamometer 46.
• a circular array of bearing cartridges 66 are mounted to each end face of the dynamometer, and rotatably engage the fixed disc, which includes a recessed rim 68 which comprises a bearing race.
• a strain gauge holder comprises first and second arms 70, 72 extending from the dynamometer and carriage member 32b respectively.
• a strain gauge 74 joins the respective arms and restricts rotation of the dynamometer relative to the carriage.
• the strain gauge comprises a transducer for converting torque between the dynamometer and the carriage into electrical current.
• the carriages 24 each comprise frame members 80 forming a rectangular configuration for supporting the rollers.
• a dynamometer support member 82 comprising a generally plate-like member extends from a transverse frame member outwardly away from the centre of the apparatus.
• Each dynamometer support has an upwardly extending bushing 84 for rotatably engaging and supporting a dynamometer 86.
• Each roller 54 is releasably engaged to a corresponding dynamometer by means of a releasable coupling 90.
• a strain gauge not shown, linking the dynamometer to the dynamometer support limits rotational movement of each dynamometer and permits accurate measurement of the rotational forces acting on the dynamometer.
• each of the rollers includes an upwardly stepped portion 66 at each respective end, which serves both as a fly wheel and a wheel stop to minimize the risk of a vehicle wheel disengaging from the roller.
• Each roller 54 has a generally hour-glass shape, and comprises a central axis, with the body of the roller diverging from generally the mid-point of the central axis at an angle of about 170° to about 179° 59' relative to the longitudinal axis of the roller.
• this arrangement facilitates accurate positioning and enhances self-centering of a wheel on the roller without undue tire wear. Lateral movement of the rollers in response to the self-centering motion is accommodated by the rollable movement of the carriage on the substrate permitted by the linear bearings.
• Figure 6 illustrates the disposition of the apparatus 10 under the front (drive) wheels of a vehicle 100 (shown in broken line).
• the vehicle under test comprises a front-wheel drive vehicle.
• the apparatus may be readily adapted for use with motorcycles and other single- wheel drive vehicles, rear-wheel drive or four-wheel drive vehicles, or other drive arrangements, by means of adapting or re-positioning the units and/or providing additional units for mating with corresponding vehicle drive wheels.
• Each dynamometer includes a rotational speed measurement means such as an internal optical position reader (referred to below), for measurement of the rotational position of the dynamometer shaft.
• the optical reader data is transmitted to the central controller described below, which calculates the rotational speed of the dynamometer and the corresponding roller.
• the dynamometers are each linked to a central control unit 200, which will now be described by reference to Figure 7.
• the control unit permits the individual left and right dynamometers to apply a substantially exactly equal load to the corresponding wheels, to simulate straight-line driving conditions. Alternatively, a controlled unequal load may be applied to simulate the vehicle driving around a curve.
• Electric signals from transducers 202 associated with strain gauges 74, indicative of the torque, may comprise amplitude or frequency variable signals. These signals, along with the signals from the optical position reader 204, are transmitted to the controller.
• the controller separately receives speed and torque information from each corresponding roller unit. In a straight-line driving simulation, all of the rollers should spin at the same speed. Since there is no mechanical link to transmit rotation movement between the roller units corresponding to the respective vehicle sides, a logical link is created by the controller to permit the controller to control the transducer to maintain identical speeds.
• the controller accordingly includes a comparator circuit 206 to assess any speed difference between the respective dynamometers. If any speed difference is detected, this information is transmitted to logic circuit 207, which in turn controls left and right motor control circuits 208 associated with each dynamometer, which in turn increase or decrease, as the case may be, the load applied by the respective dynamometer.
• the logic circuit 207 may include software that applies a power splitting algorithm based on roll speed difference to control the respective dynamometers.
• the control algorithm calculates an appropriate control signal such that more of the absorbed power will be shifted to the faster spinning roll, with more load applied by the corresponding dynamometer, in order to slow it down.
• the dynamometer attached to the slower spinning roll will be required to absorb less power, permitting the corresponding roller to speed up.
• a vehicle power output logic circuit which may be software-driven, will calculate the total power absorbed amongst all rolls, based on the following: a) the mass of the vehicle; b) the real time roll acceleration; c) the roll speed and roll load to be simulated, the latter based on known vehicle aerodynamic and friction loss factors; d) frictional losses within the dynamometer to be compensated for; and e) the force output of the vehicle.
• a display 212 displays the simulated vehicle speed, turn radius and power output.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Testing Of Engines (AREA)
• Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=4162468

Family Applications (1)

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• 1999
  • 1999-05-19 MX MXPA00011230A patent/MXPA00011230A/es unknown
  • 1999-05-19 BR BR9911030-0A patent/BR9911030A/pt not_active Application Discontinuation
  • 1999-05-19 WO PCT/CA1999/000457 patent/WO1999060363A1/en not_active Application Discontinuation
  • 1999-05-19 AU AU39225/99A patent/AU3922599A/en not_active Abandoned
  • 1999-05-19 EP EP99922000A patent/EP1080354A1/de not_active Withdrawn
  • 1999-05-19 JP JP2000549928A patent/JP2003513227A/ja active Pending
  • 1999-05-19 CN CNB998063029A patent/CN1188685C/zh not_active Expired - Fee Related
• 2001
  • 2001-12-12 HK HK01108702A patent/HK1038258A1/xx not_active IP Right Cessation

Non-Patent Citations (1)

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