TEST CONDITIONS
1. Temperature:
- Natural Ambient = 27 ± 1C.
- High Ambient = 45 ± 1C.
2. Pressure: Atmospheric pressure should be = 1bar.
3. Humidity: It should be less than 70%.
4. Fuel Temperature should be 15 ± 1º C.
PREPARATION
1. Remove all the rear side accessories (i.e. Trailer hook, Linkage drawbar, PTO cover, etc.) from the tractor taken for test.
2. Install the tractor on dynamometer with coupling shaft and PTO shaft.
3. Put ambient temperature sensor on the stand, nearly 500mm away from radiator, in front of the Tractor.
4. Insert coolant temperature sensor in the hosepipe, which is connecting water pump to radiator at the upper side and make it airtight with M-SEAL.
5. Put air intake temperature sensor in the Pre-cleaner bowl and tie it with the pre-cleaner pipe.
6. Remove the Engine sump drain plug and put the engine lub oil temperature sensor there and tight it carefully.
7. Remove the Transmission housing drain plug and put the Transmission oil temperature sensor there and tight it carefully.
8. Put Exhaust temperature sensor at exhaust elbow.
9. Fit Mercury manometer tube to the pipe in silencer elbow for measuring Exhaust backpressure.
10. Fit Mercury manometer tube to the Engine suction hose for measuring Engine suction pressure.
11. Connect the Engine fuel line with dynamometer’s fuel measuring device.
12. Place the electric heaters in stand and keep it on the both sides of tractor and connect these with electric switch.
13. Start the water pump for dynamometer.
CHECKS
1. Check for following fluid levels:
- Water / Coolant level in Radiator, and Top up the level after starting the tractor at idle RPM.
- Oil level in Engine sump, governor and air cleaner.
- Transmission oil level.
- Diesel in overhead tank (Dynamometer) or Fuel tank (Tractor).
- Electrolyte level in Battery.
2. Check for any leakage from:
- Radiator circuit.
- Fuel circuit.
- Oil circuit.
- All Drain Plugs.
3. Check for any air bubble in the fuel pipeline. If any, then remove it by bleeding.
4. Check that parking brake is applied and wedges are placed against both front and rear wheels.
5. Check for proper alignment (/ / within 2º) of coupling shaft and PTO shaft.
6. Check for greasing and leakage in Dynamometer.
7. Check for Dynamometer water pressure should be 1.6 ± 0.4 Kg/cm².
TEST PROCEDURE
1. Check for Neutral gear and start the tractor.
2. Engage the PTO drive by operating PTO lever.
3. Slowly increase the RPM of engine up to max. RPM by throttle lever and lock it.
4. Note the RPM from Dynamometer digital screen. This is No load PTO RPM.
5. Now by Pushing red button on Dynamometer panel, slowly increase the load (Torque). As the Torque will increase, RPM will come down. Start calculating horsepower for different RPM and corresponding torques by using following formula (Maintain each load for at least 4 to 5 mints. to stagnate the power) -
Torque (Nm) X RPM
Horse Power (kW) = ------------------------------
9549.305
Torque (Nm) X RPM
Horse Power (ps) = -----------------------------
7023.746
Initially hp will increase and then it will start coming down. Maintain the RPM of maximum hp by loading (red button) and unloading (green button) the tractor. Run the tractor for half an hour at this RPM.
6. Adjust the Ambient temperature as required, by switching on / off the heaters.
7. Now note down the following readings as per the test conditions at different PTO RPM.
- PTO RPM.
- Torque (Nm).
- Ambient Temperature (ºC).
- Coolant Temperature (ºC).
- Air intake Temperature (ºC).
- Engine lub oil Temperature (ºC).
- Transmission oil Temperature (ºC).
- Exhaust Temperature (ºC).
- Engine air inlet suction pressure*.
- Exhaust backpressure*.
* For engine air inlet suction pressure and exhaust backpressure, read the level of Mercury in both tubes of Manometer and see the difference.
8. For fuel consumption, there are three settings i.e.;
A=> 150cc fuel consumed in displayed seconds.
B=> 100cc fuel consumed in displayed seconds.
C=> 50cc fuel consumed in displayed seconds.
9. Following formula is used to Calculate Specific fuel consumption:
3600 X Density of fuel (gm / cc) X Volume of fuel
consumed in t seconds
Specific Fuel Consumption = --------------------------------------------------------------------
(gm / hp - hr) hp (ps) X time t (seconds)
For setting A: SFC = (3600 X 0.825 X150) / (hp X time)
For setting B: SFC = (3600 X 0.825 X100) / (hp X time)
For setting C: SFC = (3600 X 0.825 X50) / (hp X time)
{Density of diesel is taken 0.825 gm / cc.}
10. For calculating Torque Back up, search for the RPM at which Maximum Torque is coming by loading the tractor with red button of dynamometer.
Max. Torque - Torque corresponding max. hp
Torque Back up (%) = --------------------------------------------------------X 100.
Torque corresponding maximum hp
11. Measure the smoke (by sucking smoke sample through exhaust elbow) at different RPM in between maximum power and maximum torque.
12. Record the data in Observation Table (Attached).
13. After completion of Test slowly unload the engine and run it at least 10 mints at idle RPM before stopping the engine.
14. Remove the fuel connections from fuel measuring device, Detach the coupling shaft from PTO shaft after disconnecting the PTO drive, Assemble all the accessories, Take out the tractor from testing room and Park at its place.
