CA2238624C - Portable roller dynamometer and vehicle testing method - Google Patents
Portable roller dynamometer and vehicle testing method Download PDFInfo
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- CA2238624C CA2238624C CA 2238624 CA2238624A CA2238624C CA 2238624 C CA2238624 C CA 2238624C CA 2238624 CA2238624 CA 2238624 CA 2238624 A CA2238624 A CA 2238624A CA 2238624 C CA2238624 C CA 2238624C
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Abstract
A roller dynamometer is provided, having at least one supporting carriage having a rotatable roller and a dynamometer linked to the roller for measuring torque output of a vehicle. The carriages are rollable on a substrate for positioning under a vehicle. In one aspect, multiple dynamometer and roller units are provided, for engagement with multiple vehicle wheels, with the units being linked electronically for common control by a control unit that simulates either straight line or curved driving conditions. In a further aspect, the dynamometer is supported on the carriage by a rotary mount. In a further aspect, the rollers have a generally hourglass shape to permit vehicle wheel self-centering.
Description
PORTABLE ROLLER DYNAMOMETER
AND VEHICLE TESTING METHOD
FIELD OF THE INVENTION
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.
BACKGROUND OF THE INVENTION
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.
Conventional roller testing stands for motor vehicles typically comprise one or more large rollers, with a single roller spanning the left and right vehicle 2~
wheels. For example, the apparatus disclosed in US Patent 3,554,023 (Geul);
US Patent 5,154,076 (Wilson et al) and US Patent 5,193,386 (Hesse, Jr. et al), are all of this type. It is also known to provide a testing assembly for.use with a motorcycle that contacts the sole driven wheel of the vehicle (US Patent 5,429,004 - Cruickshank).
Conventionally dynamometer resistance is provided by a braking mechanism such as an electric motor, water brake, etc . However, other resistance-generating means may be employed and the present invention is not limited to the use of any particular braking means.
Conventional dynamometer-based testing devices are typically large, heavy and correspondingly expensive. This results in part from the provision of a single roller for contact with left and right driven wheels of a vehicle, that is wide enough for use with substantially all conventional vehicles, resulting in a large and heavy roller arrangement. This drawback is addressed with the present invention providing a testing apparatus whereby the individual left and right vehicle drive wheels are each provided with their own roller arrangement, with each set of rollers being separately and independently linked to a corresponding dynamometer. The individual dynamometer assemblies are thus not mechanically linked, but linked only electronically through a controller. The individual dynamometers may be then placed in communication with a common control unit to equalize the simulated loads between the vehicle drive wheels. This arrangement also permits for unequal loads and wheel speeds between the individual units, to simulate a vehicle driving around a curve.
SL>IViMARY OF TIC INVENTION
An object of the present invention is to provide an improved roller dynamometer and testing method for simulating road conditions for testing a vehicle.
AND VEHICLE TESTING METHOD
FIELD OF THE INVENTION
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.
BACKGROUND OF THE INVENTION
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.
Conventional roller testing stands for motor vehicles typically comprise one or more large rollers, with a single roller spanning the left and right vehicle 2~
wheels. For example, the apparatus disclosed in US Patent 3,554,023 (Geul);
US Patent 5,154,076 (Wilson et al) and US Patent 5,193,386 (Hesse, Jr. et al), are all of this type. It is also known to provide a testing assembly for.use with a motorcycle that contacts the sole driven wheel of the vehicle (US Patent 5,429,004 - Cruickshank).
Conventionally dynamometer resistance is provided by a braking mechanism such as an electric motor, water brake, etc . However, other resistance-generating means may be employed and the present invention is not limited to the use of any particular braking means.
Conventional dynamometer-based testing devices are typically large, heavy and correspondingly expensive. This results in part from the provision of a single roller for contact with left and right driven wheels of a vehicle, that is wide enough for use with substantially all conventional vehicles, resulting in a large and heavy roller arrangement. This drawback is addressed with the present invention providing a testing apparatus whereby the individual left and right vehicle drive wheels are each provided with their own roller arrangement, with each set of rollers being separately and independently linked to a corresponding dynamometer. The individual dynamometer assemblies are thus not mechanically linked, but linked only electronically through a controller. The individual dynamometers may be then placed in communication with a common control unit to equalize the simulated loads between the vehicle drive wheels. This arrangement also permits for unequal loads and wheel speeds between the individual units, to simulate a vehicle driving around a curve.
SL>IViMARY OF TIC INVENTION
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.
In light of the above objects, 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.
In one version, 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.
In one version, 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.
In another aspect, 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.
Further, the apparatus is conveniently provided with rollers for contact with the drive wheels of the test vehicle.
In a further aspect, 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.
In a further aspect, 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;
_ 'j _ 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.
In another embodiment of the present invention there is provided a method of simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which method comprises the steps of:
(a) providing first and second roller dynamometer assemblies, and a control means for controlling at least one of them;
(b) positioning a drive wheel of one side of the vehicle on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle on the second roller dynamometer assembly;
(c) driving the first and second roller dynamometer assemblies with the drive wheels against resistance provided by the assemblies; characterised by the step o~
(d) simulating a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
It is preferable the above embodiment further comprises the step of controlling both the first and second roller dynamometer assemblies to provide -7a-the respective resistances, simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies, measuring wheel speeds of the drive wheels, inputting signals representative thereof into the control means, comparing the signals and increasing or decreasing the resistance applied by the or each roller dynamometer assembly to the or each drive wheel to simulate the curved or straight-line driving condition, and measuring the total power output of the vehicle with an algorithm that calculates total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and. frictional losses within the dynamometer.
Preferably, the roller dynamometer assemblies are without a mechanical link, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means.
It is also preferable there is further comprising the step of permitting during testing at least one of the first and second roller dynamometer assemblies to move laterally relative to the ordinary direction of travel of the vehicle, and permitting both the first and second roller dynamometer assemblies to move laterally relative to the vehicle.
Desirably, the vehicle is a front wheel drive or a rear wheel drive vehicle.
It is further desirable there further comprises the step of providing further roller dynamometer assemblies according to the number of drive wheels of the vehicle to be tested, and performing an emissions test on the vehicle during simulation of road conditions.
Preferably, the vehicle is selected from the group consisting of a four-wheel drive, a truck or a bus.
-7b-In another embodiment of the present invention there is provided an apparatus for simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which apparatus comprises first and second roller dynamometer assemblies mechanically independent of the other, and a control means for controlling at least one of them, the arrangement being such that, in use, a drive wheel of one side of the vehicle is positioned on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle is positioned on the second roller dynamometer assembly whereby the drive wheels can drive the first and second roller dynamometer assemblies against resistance provided thereby; characterised in that the control means comprise means for providing simulation of a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
It is desirable that in use the means for providing simulation of curved driving conditions controls; the resistance applied by both the first and second roller dynamometer assemblies, the control means comprises means for simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies, and the roller dynamometer assemblies are in communication with the control means, the controller in use receiving wheel speed and torque information from the roller dynamometer assemblies, the control means comprising processing means for comparing the drive wheel speeds and torque control means for controlling the resistance applied to at least one of the drive wheels to simulate the curved or straight-line driving condition.
Preferably, the control means comprises total power absorption calculation means for measuring the total power output of the vehicle based on the total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and frictional losses within the dynamometer, the roller dynamometer assemblies are not mechanically linked, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means, that in use at least one of the first and second roller dynamometer assemblies is independently moveable during testing over a ground surface relative to the other assembly and in a direction lateral to the ordinary direction of travel of the vehicle, the or each roller dynamometer assembly comprises roller means facilitating the independent lateral movement, and the roller means comprises an array of linear bearings.
It is further desirable that in use both the first and second roller dynamometer assemblies are independently moveable, the first and second roller dynamometer assemblies each comprise a roller having an elongate generally cylindrical body having opposed ends and a middle region, the body having a generally hour-glass shape whereby the middle region has a narrowed waist relative to the opposed ends of the body for supporting a drive wheel of the vehicle at the waist, the cylindrical body comprises an upwardly stepped portion at each of the opposed ends having a diameter greater than the diameter of the roller immediately adjacent the upwardly stepped portion, and the upwardly stepped portion comprises a flywheel.
Preferably, there further comprises a rotary mount for mounting at least one dynamometer on a carriage of the roller dynamometer assemblies for limited rotational movement thereto, the rotary mount comprises first and second concentric members engaged to the carriage and the dynamometer respectively for rotation relative to each other, the first member comprises a disc and the second member comprises disc-engaging means, the disc-engaging means comprises a trunnion bearing array, and the roller dynamometer comprises a carriage frame supporting a dynamometer having roller speed and wheel torque sensing means mating with the roller that, in use, is engaged with a drive wheel of the vehicle.
-7d-In the above embodiment, it is further preferable that 'the apparatus be adapted to simulate road conditions for a front wheel drive or a rear wheel drive vehicle, the number of roller dynamometer assemblies based on the number of drive wheels of a vehicle to be tested with the apparatus, and the number is suitable to test a vehicle selected from the group consisting of a four-wheel drive, a truck or a bus.
The present invention will now be described by way of detailed description and illustration of specific examples.
BRIEF DESCRIPTION OF THE DRAWINGS
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; and Figure 7 is a block diagram showing the operation of the invention.
g Similar numerals in the drawings denote similar elements.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figures 1, 2 and 2(a), the apparatus 10 includes first and second identical carriages 24, one of which is illustrated herein. In use, 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 Figures 2 and 2(a)) 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 journalled 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.
In one version, 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. It will be seen that with modification, 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.
In a further embodiment, shown in Figures 3 and 4, 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.
Turning to the rollers 54, which are shown more particularly at Figure 5, 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 10 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.
It is found that 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). In the arrangement shown, 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.
The examples given above identify an electric motor-type dynamometer;
it will be seen that any suitable PAU may be used.
It will be further seen that the apparatus and method have been described by reference to a vehicle having at least two drive wheels, aspects of the invention may be readily adapted for use with a vehicle having a single drive wheel, such as a motorcycle.
Although the present invention has been described by way of preferred version, it will be seen that numerous departures and variations may be made to the invention without departing from the spirit and scope of the invention as defined in the claims.
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.
In light of the above objects, 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.
In one version, 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.
In one version, 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.
In another aspect, 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.
Further, the apparatus is conveniently provided with rollers for contact with the drive wheels of the test vehicle.
In a further aspect, 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.
In a further aspect, 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;
_ 'j _ 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.
In another embodiment of the present invention there is provided a method of simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which method comprises the steps of:
(a) providing first and second roller dynamometer assemblies, and a control means for controlling at least one of them;
(b) positioning a drive wheel of one side of the vehicle on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle on the second roller dynamometer assembly;
(c) driving the first and second roller dynamometer assemblies with the drive wheels against resistance provided by the assemblies; characterised by the step o~
(d) simulating a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
It is preferable the above embodiment further comprises the step of controlling both the first and second roller dynamometer assemblies to provide -7a-the respective resistances, simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies, measuring wheel speeds of the drive wheels, inputting signals representative thereof into the control means, comparing the signals and increasing or decreasing the resistance applied by the or each roller dynamometer assembly to the or each drive wheel to simulate the curved or straight-line driving condition, and measuring the total power output of the vehicle with an algorithm that calculates total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and. frictional losses within the dynamometer.
Preferably, the roller dynamometer assemblies are without a mechanical link, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means.
It is also preferable there is further comprising the step of permitting during testing at least one of the first and second roller dynamometer assemblies to move laterally relative to the ordinary direction of travel of the vehicle, and permitting both the first and second roller dynamometer assemblies to move laterally relative to the vehicle.
Desirably, the vehicle is a front wheel drive or a rear wheel drive vehicle.
It is further desirable there further comprises the step of providing further roller dynamometer assemblies according to the number of drive wheels of the vehicle to be tested, and performing an emissions test on the vehicle during simulation of road conditions.
Preferably, the vehicle is selected from the group consisting of a four-wheel drive, a truck or a bus.
-7b-In another embodiment of the present invention there is provided an apparatus for simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which apparatus comprises first and second roller dynamometer assemblies mechanically independent of the other, and a control means for controlling at least one of them, the arrangement being such that, in use, a drive wheel of one side of the vehicle is positioned on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle is positioned on the second roller dynamometer assembly whereby the drive wheels can drive the first and second roller dynamometer assemblies against resistance provided thereby; characterised in that the control means comprise means for providing simulation of a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
It is desirable that in use the means for providing simulation of curved driving conditions controls; the resistance applied by both the first and second roller dynamometer assemblies, the control means comprises means for simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies, and the roller dynamometer assemblies are in communication with the control means, the controller in use receiving wheel speed and torque information from the roller dynamometer assemblies, the control means comprising processing means for comparing the drive wheel speeds and torque control means for controlling the resistance applied to at least one of the drive wheels to simulate the curved or straight-line driving condition.
Preferably, the control means comprises total power absorption calculation means for measuring the total power output of the vehicle based on the total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and frictional losses within the dynamometer, the roller dynamometer assemblies are not mechanically linked, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means, that in use at least one of the first and second roller dynamometer assemblies is independently moveable during testing over a ground surface relative to the other assembly and in a direction lateral to the ordinary direction of travel of the vehicle, the or each roller dynamometer assembly comprises roller means facilitating the independent lateral movement, and the roller means comprises an array of linear bearings.
It is further desirable that in use both the first and second roller dynamometer assemblies are independently moveable, the first and second roller dynamometer assemblies each comprise a roller having an elongate generally cylindrical body having opposed ends and a middle region, the body having a generally hour-glass shape whereby the middle region has a narrowed waist relative to the opposed ends of the body for supporting a drive wheel of the vehicle at the waist, the cylindrical body comprises an upwardly stepped portion at each of the opposed ends having a diameter greater than the diameter of the roller immediately adjacent the upwardly stepped portion, and the upwardly stepped portion comprises a flywheel.
Preferably, there further comprises a rotary mount for mounting at least one dynamometer on a carriage of the roller dynamometer assemblies for limited rotational movement thereto, the rotary mount comprises first and second concentric members engaged to the carriage and the dynamometer respectively for rotation relative to each other, the first member comprises a disc and the second member comprises disc-engaging means, the disc-engaging means comprises a trunnion bearing array, and the roller dynamometer comprises a carriage frame supporting a dynamometer having roller speed and wheel torque sensing means mating with the roller that, in use, is engaged with a drive wheel of the vehicle.
-7d-In the above embodiment, it is further preferable that 'the apparatus be adapted to simulate road conditions for a front wheel drive or a rear wheel drive vehicle, the number of roller dynamometer assemblies based on the number of drive wheels of a vehicle to be tested with the apparatus, and the number is suitable to test a vehicle selected from the group consisting of a four-wheel drive, a truck or a bus.
The present invention will now be described by way of detailed description and illustration of specific examples.
BRIEF DESCRIPTION OF THE DRAWINGS
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; and Figure 7 is a block diagram showing the operation of the invention.
g Similar numerals in the drawings denote similar elements.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figures 1, 2 and 2(a), the apparatus 10 includes first and second identical carriages 24, one of which is illustrated herein. In use, 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 Figures 2 and 2(a)) 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 journalled 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.
In one version, 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. It will be seen that with modification, 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.
In a further embodiment, shown in Figures 3 and 4, 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.
Turning to the rollers 54, which are shown more particularly at Figure 5, 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 10 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.
It is found that 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). In the arrangement shown, 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.
The examples given above identify an electric motor-type dynamometer;
it will be seen that any suitable PAU may be used.
It will be further seen that the apparatus and method have been described by reference to a vehicle having at least two drive wheels, aspects of the invention may be readily adapted for use with a vehicle having a single drive wheel, such as a motorcycle.
Although the present invention has been described by way of preferred version, it will be seen that numerous departures and variations may be made to the invention without departing from the spirit and scope of the invention as defined in the claims.
Claims (66)
1. A roller dynamometer vehicle testing assembly for simulating road conditions for a vehicle having at least two drive wheels, comprising:
first and second roller carriages;
carriage support means for supporting at least one of said first and second carriages on a substrate whereby said at least one carriage may be moved laterally relative to said vehicle on said substrate;
each carriage rotatably supporting a roller for independently supporting and rotatably contacting a vehicle drive wheel; and each carriage supporting a dynamometer, each dynamometer having speed and torque sensing means and engaged to a corresponding roller for applying a load to said corresponding roller whereby straight and curved road conditions are simulated on a vehicle engaged with said apparatus.
first and second roller carriages;
carriage support means for supporting at least one of said first and second carriages on a substrate whereby said at least one carriage may be moved laterally relative to said vehicle on said substrate;
each carriage rotatably supporting a roller for independently supporting and rotatably contacting a vehicle drive wheel; and each carriage supporting a dynamometer, each dynamometer having speed and torque sensing means and engaged to a corresponding roller for applying a load to said corresponding roller whereby straight and curved road conditions are simulated on a vehicle engaged with said apparatus.
2. The apparatus as defined in claim 1, wherein each said carriage has rotatably mounted thereto at least two spaced-apart rollers in parallel relationship for rotatably supporting and engaging said wheel.
3. The apparatus as defined in claim 1, wherein said carriage support means comprises roller means.
4. The apparatus as defined in claim 3, wherein said roller means comprises an array of linear bearings mounted to each of said carriages.
5. The apparatus as defined in claim 1, wherein each of said carriages includes carriage support means.
6. The apparatus as defined in claim 1, wherein said. rollers each comprise an elongate generally cylindrical body having opposed ends and a middle region, said body having a generally hour-glass shape whereby the middle region has a narrowed waist relative to the opposed ends of said body.
7. The apparatus as defined in claim 1, wherein said rollers each comprise a generally cylindrical body having opposed ends, and having an upwardly stepped portion at each of said opposed ends having a diameter whereby the diameter of said stepped portion is greater than the diameter of said roller immediately adjacent said portion.
8. The apparatus as defined in claim 7, wherein said stepped portion comprises a fly wheel.
9. The apparatus as defined in claim 1, wherein said dynamometers each comprise an electric motor.
10. The apparatus as defined in claim 1, further incorporating a rotary mount for mounting at least one of said dynamometers to a corresponding of said carriages for limited rotational movement relative to said carriage.
11. The apparatus as defined in claim 10, wherein said rotary mount comprises first and second concentric members engaged to said dynamometer and carriage respectively for rotation relative to each other.
12. The apparatus as defined in claim 11, wherein said first member comprises a disc and said second member comprises disc engaging means.
13. The apparatus as defined in claim 12, wherein said disc engaging means comprises a trunnion bearing array.
14. The apparatus as defined in claim 1, wherein said dynamometers are in communication with a controller, said controller receiving wheel speed and torque information from each of said dynamometers, and having processing means for comparing rotary speed differences between said first and second dynamometers and torque control means for controlling the torque applied by at least one of said dynamometers to substantially equalize the respective rotary speeds of said rollers.
15. The apparatus as defined in claim 14, wherein said torque control means control both of said dynamometers.
16. The apparatus as defined in claim 14, wherein said control means directs a faster spinning dynamometer to apply a greater amount of power absorption to a faster spinning roll, relative to a slower spinning dynamometer.
17. The apparatus as defined in claim 14, wherein said controller 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 dynamometers.
18. The apparatus as defined in claim 14, wherein said torque control means further permits control of said dynamometers to apply a controlled unequal rotary speed of the respective rollers to simulate a curved driving condition.
19. A roller dynamometer vehicle testing assembly for simulating road conditions for a vehicle, comprising:
at least one roller rotatably mounted to a frame for supporting and rotatably contacting a vehicle wheel;
a dynamometer engaged to said at least one roller for applying a load to the roller whereby straight or curved road conditions are simulated on the vehicle engaged to said apparatus;
a rotary mount for engaging said dynamometer to said frame for rotational movement relative to said frame, said rotary mount comprising first and second concentric members engaged to said dynamometer and carriage respectively.
at least one roller rotatably mounted to a frame for supporting and rotatably contacting a vehicle wheel;
a dynamometer engaged to said at least one roller for applying a load to the roller whereby straight or curved road conditions are simulated on the vehicle engaged to said apparatus;
a rotary mount for engaging said dynamometer to said frame for rotational movement relative to said frame, said rotary mount comprising first and second concentric members engaged to said dynamometer and carriage respectively.
20. The apparatus as defined in claim 19, wherein said first member comprises a disc and said second member comprises disc engaging means.
21. The apparatus as defined in claim 20, wherein said disc engaging means comprises a trunnion bearing array.
22. The apparatus as defined in claim 19, wherein said at least one roller has a generally hourglass shape for self-centering of said vehicle wheel.
23. A roller dynamometer for simulating road conditions for a vehicle having at least two drive wheels, comprising:
first and second roller dynamometer assemblies mechanically independent of the other, each said roller dynamometer assembly comprising at least one roller for contact with a vehicle drive wheel and engaged to a corresponding dynamometer, said first and second dynamometer assemblies for independent rotation relative to each other and each having rotary speed and torque 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 between said dynamometers and controlling at least one of said dynamometers in response to said speed differences.
first and second roller dynamometer assemblies mechanically independent of the other, each said roller dynamometer assembly comprising at least one roller for contact with a vehicle drive wheel and engaged to a corresponding dynamometer, said first and second dynamometer assemblies for independent rotation relative to each other and each having rotary speed and torque 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 between said dynamometers and controlling at least one of said dynamometers in response to said speed differences.
24. The apparatus as defined in claim 23, wherein said logic circuit controller controls the power absorption means of said at least one dynamometer to achieve straight-line driving simulation.
25. The apparatus as defined in claim 23, wherein said logic circuit controller controls the power absorption means of said at least one dynamometer to achieve curved driving simulation.
26. The apparatus as defined in claim 23, wherein said dynamometer comprises an electric motor.
27. The apparatus as defined in claim 23, wherein said controller 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 dynamometers.
28. The apparatus as defined in claim 23, wherein said control means controls both of said dynamometers.
29. A method for simulating road conditions for a vehicle, comprising the steps of:
a) providing first and second roller dynamometer assemblies each having torque and rotational speed sensors, and a controller for receiving speed and torque information from each dynamometer assembly and independently controlling the resistance applied thereby;
b) providing a test vehicle having at least two drive wheels;
c) supporting said at least two drive wheels on corresponding first and second roller dynamometer assemblies, each said assemblies being mechanically independent of the other;
d) driving said at least two drive wheels with said test vehicle;
e) independently measuring the speed and torque of said at least two drive wheels;
and f) independently controlling with said controller at least one of said first and second roller dynamometer assemblies to control the rotary speed thereof.
a) providing first and second roller dynamometer assemblies each having torque and rotational speed sensors, and a controller for receiving speed and torque information from each dynamometer assembly and independently controlling the resistance applied thereby;
b) providing a test vehicle having at least two drive wheels;
c) supporting said at least two drive wheels on corresponding first and second roller dynamometer assemblies, each said assemblies being mechanically independent of the other;
d) driving said at least two drive wheels with said test vehicle;
e) independently measuring the speed and torque of said at least two drive wheels;
and f) independently controlling with said controller at least one of said first and second roller dynamometer assemblies to control the rotary speed thereof.
30. A method as defined in claim 29, comprising the further step of 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.
31. A method as defined in claim 29, wherein the first and second dynamometer assemblies are controlled to simulate straight-line driving conditions.
32. A method as defined in claim 29, wherein the first and second dynamometer assemblies are controlled to simulate curved driving conditions.
33. A method as defined in claim 29, wherein both of said dynamometers are independently controlled by said controller.
34. A method of simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which method comprises the steps of:
(a) providing first and second roller dynamometer assemblies, and a control means for controlling at least one of them;
(b) positioning a drive wheel of one side of the vehicle on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle on the second roller dynamometer assembly;
(c) driving said first and second roller dynamometer assemblies with said drive wheels against resistance provided by the assemblies;
characterised by the step of:
(d) simulating a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel. on the other side of the vehicle.
(a) providing first and second roller dynamometer assemblies, and a control means for controlling at least one of them;
(b) positioning a drive wheel of one side of the vehicle on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle on the second roller dynamometer assembly;
(c) driving said first and second roller dynamometer assemblies with said drive wheels against resistance provided by the assemblies;
characterised by the step of:
(d) simulating a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel. on the other side of the vehicle.
35. A method as claimed in claim 34, further comprising the step of controlling both said first and second roller dynamometer assemblies to provide the respective resistances.
36. A method as claimed in claim 34 or 35, further comprising the step of simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies.
37. A method as claimed in any one of claims 34 to 36, further comprising the steps of measuring wheel speeds of the drive wheels, inputting signals representative thereof into said. control means, comparing said signals and increasing or decreasing the resistance applied by the or each roller dynamometer assembly to the or each drive wheel to simulate the curved or straight-line driving condition.
38. A method as claimed in claim 37, further comprising the step of measuring the total power output of the vehicle with an algorithm that calculates total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and frictional losses within the dynamometer.
39. A method as claimed in any one of claims 34 to 38, wherein said roller dynamometer assemblies are without a mechanical link, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means.
40. A method as claimed in claim 39, further comprising the step of permitting during testing at least one of the first and second roller dynamometer assemblies to move laterally relative to the ordinary direction of travel of the vehicle.
41. A method as claimed in claim 40, further comprising the step of permitting both the first and second roller dynamometer assemblies to move laterally relative to the vehicle.
42. A method as claimed in any one of claims 34 to 41, wherein said vehicle is a front wheel drive or a rear wheel drive vehicle.
43. A method as claimed in any of claims 34 to 41, further comprising the step of providing further roller dynamometer assemblies according to the number of drive wheels of the vehicle to be tested.
44. A method as claimed in claim 43, wherein said vehicle is selected from a group consisting of a four-wheel drive, a truck or a bus.
45. A method as claimed in any one of claims 34 to 44, further comprising the step of performing an emissions test on the vehicle during simulation of road conditions.
46. An apparatus for simulating road conditions for a vehicle having at least one drive wheel on either side thereof, which apparatus comprises first and second roller dynamometer assemblies, and a control means for controlling at least one of them, the arrangement being such that, in use, a drive wheel of one side of the vehicle is positioned on the first roller dynamometer assembly and a drive wheel of the other side of the vehicle is positioned on the second roller dynamometer assembly whereby the drive wheels can drive said first and second roller dynamometer assemblies against resistance provided thereby;
characterised in that the control means comprise means for providing simulation of a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
characterised in that the control means comprise means for providing simulation of a curved driving condition by controlling at least one of the first and second dynamometer assemblies so that the resistance applied to the or each drive wheel on one side of the vehicle is different to the resistance applied to the or each drive wheel on the other side of the vehicle.
47. An apparatus as claimed in claim 46, wherein in use said means for providing simulation of curved driving conditions controls; the resistance applied by both said first and second roller dynamometer assemblies.
48. An apparatus as claimed in claim 46 or 47, wherein said control means comprises means for simulating straight-line driving conditions during a vehicle test by substantially equalising the resistances applied by the first and second roller dynamometer assemblies.
49. An apparatus as claimed in any one of claims 46 to 48, wherein the roller dynamometer assemblies are in communication with the control means, the controller in use receiving wheel speed and torque information from the roller dynamometer assemblies, the control means comprising processing means for comparing the drive wheel speeds and torque control means for controlling the resistance applied to at least one of the drive wheels to simulate the curved or straight-line driving condition.
50. An apparatus as claimed in claim 49, wherein said control means comprising total power absorption calculation means for measuring the total power output of the vehicle based on the total power absorbed by the first and second roller dynamometer assemblies, calculated as a function of the mass of the vehicle, the speed and acceleration of each roller of the first and second roller dynamometer assemblies, and a value associated with the vehicle aerodynamic and frictional losses within the dynamometer.
51. An apparatus as claimed in any of claims 46 to 50, wherein said roller dynamometer assemblies without a mechanical link, a link between the roller dynamometer assemblies being in the form of an electronic link provided by the control means.
52. An apparatus as claimed in claim 51, wherein in use at least one of the first and second roller dynamometer assemblies is independently moveable during testing over a ground surface relative to the other assembly and in a direction lateral to the ordinary direction of travel of the vehicle.
53. An apparatus as claimed in claim 52, wherein the or each roller dynamometer assembly comprises roller means facilitating said independent lateral movement.
54. An apparatus as claimed in claim 53, wherein said roller means comprises an array of linear bearings.
55. An apparatus as claimed in any one of claims 52 to 54, wherein in use both the first and second roller dynamometer assemblies are independently moveable.
56. An apparatus as claimed in any one of claims 46 to 55, wherein the first and second roller dynamometer assemblies each comprise a roller having an elongate generally cylindrical body having opposed ends and a middle region, said body having a generally hour-glass shape whereby the middle region has a narrowed waist relative to the opposed ends of said body for supporting a drive wheel of the vehicle at said waist.
57. An apparatus as claimed in claim 56, wherein said cylindrical body comprises an upwardly stepped portion at each of said opposed ends having a diameter greater than the diameter of said roller immediately adjacent the upwardly stepped portion.
58. An apparatus as claimed in claim 57, wherein said upwardly stepped portion comprises a flywheel.
59. An apparatus as claimed in any one of claims 46 to 58, further comprising a rotary mount for mounting at least one dynamometer on a carriage of the roller dynamometer assemblies for limited rotational movement thereto.
60. An apparatus as claimed in claim 59, wherein said rotary mount comprises first and second concentric members engaged to said carriage and said dynamometer respectively for rotation relative to each other.
61. An apparatus as claimed in claim 60, wherein said first member comprises a disc and said second member comprises disc-engaging means.
62. An apparatus as claimed in claim 61, wherein said disc-engaging means comprises a trunnion bearing array.
63. An apparatus as claimed in any one of claims 46 to 62, wherein each roller dynamometer assembly comprises a carriage frame supporting a dynamometer having roller speed and wheel torque sensing means mating with the roller that, in use, is engaged with a drive wheel of the vehicle.
64. An apparatus as claimed in any one of claims 46 to 63, adapted to simulate road conditions for a front wheel drive or a rear wheel drive vehicle.
65. An apparatus as claimed in any one of claims 46 to 63, further comprising a number of roller dynamometer assemblies based on the number of drive wheels of a vehicle to be tested with the apparatus.
66. An apparatus as claimed in claim 65, wherein said number is suitable to test a vehicle, said vehicle selected from the group consisting of a four-wheel drive, a truck or a bus.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000549928A JP2003513227A (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle test method |
| CNB998063029A CN1188685C (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle testing method |
| BR9911030-0A BR9911030A (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle test method |
| PCT/CA1999/000457 WO1999060363A1 (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle testing method |
| EP99922000A EP1080354A1 (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle testing method |
| MXPA00011230A MXPA00011230A (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle testing method. |
| AU39225/99A AU3922599A (en) | 1998-05-20 | 1999-05-19 | Portable roller dynamometer and vehicle testing method |
| HK01108702A HK1038258A1 (en) | 1998-05-20 | 2001-12-12 | Portable roller dynamometer and vehicle testing method. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US4735397P | 1997-05-21 | 1997-05-21 | |
| US60/047,353 | 1997-05-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2238624A1 CA2238624A1 (en) | 1998-11-21 |
| CA2238624C true CA2238624C (en) | 2006-08-01 |
Family
ID=21948489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2238624 Expired - Fee Related CA2238624C (en) | 1997-05-21 | 1998-05-20 | Portable roller dynamometer and vehicle testing method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2238624C (en) |
-
1998
- 1998-05-20 CA CA 2238624 patent/CA2238624C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2238624A1 (en) | 1998-11-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |