TESTING PROCEDURE FOR HYDRAULIC LIFT ASSEMBLY

Conditions:
1. EP-80 Hydraulic Oil to be used for test at 50º-60ºC.
2. System relief valve to be set at designed cranking pressure (175Kg/cm²).
3. System should be fitted with all accessories. Load at the end of lower links 1000Kg.
4. Connect the pressure gauge on R.V. hsg. (As shown in Figure).

CONTROL VALVE

1.) Pressure setting of back Pressure Valve:
i) Bring both operating levers to lower most position of control sector.
ii) Run the tractor at low idle R.P.M.
iii) Read pressure on pressure gauge, if oil pressure* is not O.K., then adjust by adding or removing shims.
iv) Move position lever towards up of control sector assy, to ensure that lifting with load takes place, check back pressure* valve setting again, after lifting. It should be equal to the previous value as in clause iii.
v) Now run the tractor at full throttle and check backpressure* valve setting again. If not OK then replace the spring of the valve with new one.
vi) Move position lever up & down to ensure lifting and lowering.

2.) Dropping test:
i) Raise the lift with load on lower links. Keep response valve in open position. Shut off engine, dropping at the end of lower links should not be more than 20mm in 30 minutes. Dropping to be checked near to transport position at 50º to 60ºC oil temp.
ii) Since the internal kinematics is automatic, internal leakage at any point in the CKT is corrected immediately by feed back linkage. At the time of carrying out dropping test, keep the engine running at full throttle and note down no of corrections (Jerks). Maximum permissible numbers of corrections to be 05 in 05 minutes.
iii) If results are not within limit, then find out remedies of dropping.

RESPONSE VALVE

1. Pressure setting of check valve in response valve housing
i. Remove relief valve from Ram Cylinder
ii. Bring the position lever at the end of control sector assy in external CKT position.
iii. Run the tractor at low idle R.P.M. and read the pressure reading on pressure gauge. This will indicate check valve pressure setting. If not ok, adjust by means of shims.
iv. Response control valve may be open or closed.

2. Dropping Test:
i) Fit relief valve to hydraulic cylinder
ii) Raise the lift with load (1000Kg) on lower links. Keep the response valve in close position. Dropping at the end of lower links should not be more than 20mm in 30 minutes. If dropping is more than this valve, than find out cause & remedies of dropping

NOTE:- *Pressure setting of Back Pressure Valve is in Optimization stage

METHOD FOR DETERMINATION OF CENTER OF GRAVITY OF AGRICULTURE TRACTORSMETHOD FOR DETERMINATION OF CENTER OF GRAVITY OF AGRICULTURE TRACTORS

GENERAL REQUIREMENTS

1. The tractor shall be clean and shall be tested in normal working conditions.
2. The Radiator, Sump, Hydraulic and other reservoirs shall be filled to the specified levels.
3. Tools, Spare Tyre and Loose accessories and equipment shall be complete as supplied and shall be in normal storage positions.
4. Tyre pressure shall be as per specifications.
5. In conducting the test, Following measuring tolerances shall be observed :

* Distance => ±0.5%.

* Mass => ±0.5%.

* Tyre pressure => ±5%.



PROCEDURE

A – Determination of Horizontal Co-ordinate of C.G.:

1. Determine the mass (m) of the whole tractor, Front Reaction Rf, Rear Reaction Rr, RHS Reaction RRh, and LHS Reaction RLh of the Tractor.
2. Measure the Wheel base (b) of the Tractor.
3. Measure the Rear wheel Track width (t) of the Tractor.
4. Calculate the x co-ordinate (along the plain of symmetry of the tractor) of C.G., by following formula :

 
           Rf
x = ---------- b
           m

5. Calculate the y co-ordinate (across the plain of symmetry of the tractor) of C.G., by following formula:

        RRh
y = -------- t
         m


OR 


           RLh
y = ------------ t
            m

B – Determination of Vertical co-ordinate (z):

1. Suspend the Tractor from front end, by putting a load cell in between the suspension rope / wire.
2. Measure the distance D, from the axis of the rear wheels to the plane containing the point of lifting of the tractor in horizontal position.
3. Put 75 kg mass on the operators seat to compensate the operator’s weight.
4. Measure the Rolling Radius of the Rear Tyre (R).
5. Just lift the tractor from the ground, so that the front wheels are just above the ground level. Measure the load P0, required for lifting, by load cell.
6. Measure the tilt angle α0 at this condition.
7. Now Lift the Tractor at different angles (upto 25º ), from horizontal.
8. As the Tractor is lifted, part of the mass of the tractor at the front will be transferred to the rear and the load Req to lift the tractor get reduced. Measure these loads P0, P1, P2, P3, P4, …………. Pn.
9. Measure the Corresponding Tilt angles α0, α1, α2, α3, α4 ……….., αn.
10. The Vertical co-ordinate z is determined by the following formula :

                   D ( P0 – Pn )
z = R + ------------------------- t
             m ( tan αn - tan α0 )


11. The value of z are determined at different angles and then average of all represents the vertical co-ordinate of the C.G.

TEST PROCEDURE FOR CHECKING EXTERNAL DIRECTIONAL CONTROL VALVE

Preparation:

1. Park the Tractor on level ground.
2. Remove Male part of Quick Release coupler and fix it on Female part.
   
   
   
3. Connect Pressure gauge on quick release coupler (as shown in figure) fitted with External Directional Control Valve, with suitable adopter.
4. Start the tractor.
5. Operate External control valve Lever and note down the pressure at different engine rpm, i.e. idle, rated and maximum.

Observation:

1. Check for any leakage, if exist record it.
2. Record the Pressure at various rpm.

Conclusion:

1. Pressure of Oil should be = 180 ± 5 bar.
2. There should not be any leakage.

TEST PROCEDURE FOR OIL PULL OVER OF OIL BATH TYPE AIR CLEANER

Preparation:

1. Weigh the Sample of Air Cleaner with out Oil.
2. Fill oil up to the Marked level in the Air Cleaner Bowl.
3. Weigh the Air Cleaner With Oil.
4. Pour 10% more oil in the Air Cleaner Bowl.
5. Weigh the Air Cleaner with Additional Oil.
6. Record the mass of total oil in the Air Cleaner.

Step 1 (On Level Ground):

1.  Park the Tractor on the Level Ground and mount the Air Cleaner on it.
2. Attach Mercury Manometer on suction hose to measure Suction Pressure (as shown in figure).
   
   
3. Start the Tractor and keep it on full Throttle for 15 minutes.
4. After this put the tractor on Sudden acceleration and deceleration (Full throttle for 30 seconds and Low idle for 30 seconds) up to 15 minutes.
5. Record Observations.

Step 2 (On 15º Slope):

1.  Now park the tractor on the 15 deg slope (Front of Tractor on upper side).
2. Start the Tractor and keep it on full Throttle for 15 minutes.
3. After this put the tractor on sudden acceleration and deceleration (Full throttle for 30 seconds and Low idle for 30 seconds) up to 15 minutes.
4. Record Observations.

Observations for Both steps:

1. Air Cleaner Suction Pressure (Difference in Hg column height of Manometer).
2. Take out Air Cleaner from the Tractor and weigh it.
3. Record the mass of Oil in the Air Cleaner.
4. Calculate the Percentage Loss of Oil.

Conclusion:

1.  Percentage loss of Oil should be less than 0.20% of Total Oil in both the cases.
2. Suction Pressure of Air Cleaner should be less than 18 mm of Mercury Column.

Reference: - IS code; 12207 – 1999