FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Test Rig And Method Of Testing Pull Test Of Passenger Car With
Continuous Variable Transmission


APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001, Maharashtra, India
INVENTOR
Shinde Mahesh Pratap
An Indian National
of TATA MOTORS LIMITED,
An Indian company having its registered office
At Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner
in which it is to be performed.


FIELD OF INVENTION
This invention relates to Pull (traction) test rig and more particularly to test rig for the testing of pulling efforts of a passenger car having continuous variable transmission (CVT), as measure of Tractive power of a vehicle.
BACKGROUND OF INVENTION
As a conventional practice, an automobile's ability to overcome load (due to laden condition and / or road inputs in relation to tractive efforts required) is defined and decided by virtue of its engine power and torque; measured on an Engine or Chassis Dynamometer. This necessitates specific set up, higher manpower utilization and is also time consuming for quality audit on series production vehicles (often termed as "end of line" testing). In present scenario, the demand on higher production rate compels industries to cut down / speed up cycle time per vehicle (inclusive of testing vehicles after they are rolled down from production line).
To address the above complexity and constraints, there was a need of quick and fairly accurate method for checking production vehicle performance in terms of capability of vehicle to "pull" specific load. This is to ensure quality and control variation in specified range of performance values. This would mean devising a simple & quick method of checking, giving an indication of performance for Passenger cars using Continuous variable transmission (CVT).
OBJECTS OF THE INVENTION
The main objective of the present invention is to provide a device or Pull measurement test rig for testing Cars (with CVT) at the end of production line and
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for faster primary tuning of CVT assembly in development stage.
Another object of the present invention is to provide the Pull test rig, which facilitates to compare the results of production lot and ensure performance values are within specified limits / range.
Yet another object of the present invention is to provide Pull test rig, which requires less time for testing various test units (Automobiles) and also is easy to handle.
BRIEF DESCRIPTION OF INVENTION
According to the present invention, Pull test rig for testing production cars with CVT comprises; A rigid frame (1) to mount other structures and fixed to the ground, Cross member plate (2) to fix measuring device, a Load cell (3) whose one end is fixed to cross member plate (4), a plate with equi-pitched holes (4) on which other end of load cell (3) is attached, two pulleys (5) floating on a Shaft with bearing (6) and mounted on a frame (I) to channel the ropes for smooth operation, two steel wire ropes (7) with adequate stiffness running parallel to each other and horizontal to ground (visually), Existing Hooks of vehicle or suitable attachment (8) to connect other ends of steel wire ropes (7) and a vehicle (9) under test. A load indicator (10) having its own power supply, is stationed on cross member plate (2) is used to display the results (Pull, Kgf) and/or record through a data logger. The load indicator may have an option of "peak hold" for recorded value.
The schematic diagram of the arrangement is shown in figure no.2 and 3. BRIEF DESCRIPTION OF DRAWINGS
Figure 1 show the block diagram of the present invention.
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Figure 2 show the top view of the Pull (measurement) test rig in accordance with the present invention
Figure 3 shows the side view of the pull (measurement) test rig in accordance with the present invention.
DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating only a preferred embodiment of the invention, and not for the purpose of limiting the same,
According to the present invention, Pull test rig for testing production cars with CVT comprises; A rigid frame (1) to mount other structural members and suitably fixed to the ground, Cross member plate (2) to mount fixed end of measuring device, a Load cell (3), a plate with equi-pitched holes (4) which will be attached to other end of load cell (3) and used for adjusting parallelism of wire ropes, two pulleys (5) floating on a Shaft with bearing (6) and mounted on a frame (1) to ensure smooth pulling through ropes, two steel wire ropes (7) running parallel to each other and horizontal to ground (visually), Existing Hooks of vehicle or suitable attachment (8) on vehicle to connect other ends of steel wire ropes (7) and a vehicle (9) under test.
A load indicator (10) with its own power supply and stationed on cross member plate (2); is used to display the resultant value (Pull, Kgf) and/or record values through a data logger.
The Test Rig is small and simple in construction. It contains a rigid frame (1) which is fixed to the ground, suitably. The two columns of this frame are connected with Cross member plate (2) on which fixed end of load cell (3) is connected. The load cell (3) currently proposed is of 500 kg capacity with a stand alone load indicator
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with power supply (10) and measures Pull force in kg. The other end of load cell is connected to moving plate (4), which has equi-spaced holes to couple the steel wire ropes (7) in parallel. These ropes (7) have adequate stiffness and run through two pulleys (5) which are floating on a shaft supported by bearings (6) at either ends and mounted at lower part of frame (1). The plate (4), Pulleys (5) and Shaft with bearings (6) arrangement, ensures that both wire ropes (7) are running parallel to each other and are horizontal to the ground for correctness of measurement. The arrangement up to this point is common set of device, which can be transported to any other location, if required.
After ensuring the preparation of test vehicle/s and confirming calibration for load cell and Engine speed meter in Vehicle; the measurements can start in cold condition of the vehicle. During all measurements, all auxiliary equipments such as Lighting, HVAC, Music system, etc; are to be in "OFF" mode.
The ropes (7) running over pulleys (5) are then hooked to the existing hook or suitable arrangement (8) on the test vehicle (9). It is ensured that the test vehicle is normal to the plane of Frame (1), i.e. effective length of both steel wire ropes (7) is nearly equal.
The vehicle under test (9) is then started and put in forward gear. With gradual and constant rate, the test vehicle (9) is accelerated as if driving in straight line, till any one of the following conditions are met - a) Wheels of the vehicle start slipping on ground OR b) Engine speed reaches rpm for rated maximum torque OR 5 seconds of revving up engine, if none above two conditions are reached. Record this Pull (traction force, Tj) value in Kgf; as indicated on Load indicator (10) and also record Engine speed (rpm) from Vehicle Instrument console (this will be pre-calibrated suitably to indicate actual engine speed). This will be logged as "Cold" pull.
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Load indicator (10) is activated in "peak hold" mode for ease of recording the value, if required manually. However, if a data logger is connected, stream of values are automatically recorded and are available later for analysis.
Disconnect the steel wire ropes (7) from vehicle end hooks (8). Run the vehicle for the speed conditions & time duration in prescribed manner. Bring back the vehicle to test rig station and keep it on idling without cutting of the engine. Re-connect the wire ropes (7) to vehicle end hooks (8) and repeat the procedure for measurement. Note down Pull load (Kgf) & engine speed (rpm). This will be "Hot" pull of the same vehicle. Both these values can be compared with desired tolerance band to decide on Pass/Fail criteria.
For Confirmation on consistency / repeatability of test & results, Hot pull measurements can be taken for consecutive 3~5 cycles. To ensure fairly same test condition of vehicle, non contact type external temperature probe is to be used to crosscheck warmed-up condition with respect to "stabilized" radiator water temperature.
Similarly, for measurements in "reverse" direction of vehicle motion, wire ropes (7) can be attached to the front of the vehicle with vehicle facing towards the Frame (1). Measurement process remains same as that explained above.
These values/readings are then logged against test vehicle details (such as engine & chassis number) for quality audit and for future use. To further reduce testing time per vehicle, multiple vehicles can be tested in phased out manner, by measuring cold and hot pull, alternately for two or more vehicles.
On this Test rig, parameters like engine stalling speed, pull force at cold and hot condition of the vehicle can be measured.
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Total data, then be stored in data logger or in the form of excel sheets for further computation, segregation, analysis and providing acceptance range of corresponding values. Inference from the data will point out variations observed over a longer period of time; thus, prompting for corrective actions in production process and/or quality improvements, if any.
Advantages of Test Rig:
• With the test setup/rig according to the present invention, the pull force (traction value) of automotive vehicles having continuous variable transmission (CVT) is capable of being measured.
• The series production vehicles for its predicted performance in terms of acceleration as perceived by customer is tested.
• Due to the very simple set up and testing procedure of the present invention, testing is done quicker and thereby saves lot of time (which is essential for reducing production cycle time).
• The test rig according to this invention provides quick, fairly accurate results and require no special testing skills and/or high investment, thus, effectively reducing overhead cost for the product.
• The rig according to the present invention can be operated with less man¬power, wherein only one person operates the rig and also perform as test driver, unlike that in the conventional method.
• The records of test conducted as per the method of the present invention can provide database to infer deviations in quality of vehicle performance during its entire lifecycle (of continued production)
• The test rig according to the present invention can be made common for wide range of vehicles (in terms of performance level) without requiring any change except may be load cell capacity.
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The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is . intended that all such modifications and alterations be included in, so far as they come within the scope of the invention as claimed of the equivalents thereof.
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WE CLAIM
1) A Pull test measuring device for testing vehicles provided with continuous
variable transmission comprising;
a rigid frame with at least two columns fixed to the ground, said columns being connected by a (first) cross member plate;
a load measuring device having a fixed end being connected to said (first) cross member plate and other end being mounted on a plate provided with equi-pitched apertures;
at least two pulleys floating on a shaft with bearings mounted on a said rigid frame; and
at least two cables running parallel to each other , one end of said cables connected to said second mounting plate through apertures provided for adjustments and other end of said cables passing over said pulleys and attached to hooking means provided on said vehicle.
2) The device as claimed in Claim 1 wherein the load measurement means includes a load cell and a load indicator connected to said load cell to display the pull force and/or record values.
3) The device as claimed in Claim 2 wherein the said load cell is preferably of 500 kg capacity.
4) The device as claimed in Claim 1 wherein the hooking means is either an existing hook provided on said vehicle or an external hooking arrangement connecting the cables with the vehicle.
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5) The device as claimed in Claim 1 wherein said cables are preferably steel wire ropes with adequate stiffness.
6) A method of measurement of the traction power of a vehicle using the device as claimed in the preceding claims comprising the steps of:
hooking the cables to the hooking arrangement at the front or rear of said vehicle;
starting and accelerating the vehicle in forward gear at constant rate until a) wheels of the vehicle start slipping on ground OR b) engine speed reaches rpm for rated maximum torque OR c) uptil 5 seconds of revving up engine;
recording cold pull force (Kgf) as indicated on said load indicator means and engine speed (rpm) from vehicle Instrument console;
disconnecting said cables from said vehicle;
running the vehicle for the speed conditions and time duration in prescribed manner;
Re-connecting the said cables to said vehicle, which is now kept in idling mode and repeat the procedure for measurement as described above;
Recording hot pull force (Kgf) and engine speed (rpm); and
Comparing said cold pull and hot pull force values with desired tolerance band to decide on Pass/Fail criteria.
7) The method as claimed in claim 1, comprising the preliminary step of ensuring that the test vehicle is normal to the plane of said rigid frame.
8) A Pull test measuring device for testing vehicles provided with continuous variable transmission substantially as hereinabove described with reference to the accompanying drawings.
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9) A method of measurement of the traction power of a vehicle substantially as hereinabove described with reference to the accompanying drawings.
Dated this 22nd day of December 2008
TATA MOTORS LIMITED By their Agent & Attorney

(Karuna Goleria) of DePENNING & DePENNING
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