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GB/T 3871.9-2006 English PDF (GBT3871.9-2006)

GB/T 3871.9-2006 English PDF (GBT3871.9-2006)

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GB/T 3871.9-2006: Agricultural tractors -- Test procedures -- Part 9: Power tests for drawbar

This part specifies the test procedures for determining the power available at the drawbar on agricultural tractors of the wheeled, track-laying or semi-tracklaying type. The statement of the power rating of the drawbar is specified clause 6.4. 2 Normative references The following part contains provisions which, through reference in this text, constitute provisions of this part. At the time of publication, the edition indicated was valid. All standards are subject to revision, parties who reach an agreement based on this part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA ICS 65.060.10 T 61
GB/T 3871.9-2006
Replacing GB/T 3871.9-1993
Agricultural tractors - Test procedures ?€?
Part 9. Power tests for drawbar
(ISO 789-9.1990, MOD)
Issued on. February 06, 2006 Implemented on. April 01, 2006
Issued by. General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration of the People's Republic of China. Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Definitions ... 6
4 Measurement units and permissible tolerances ... 8
5 General requirements ... 8
6 Test procedure ... 10
Appendix A (Normative) Drawbar test report ... 15
Appendix B (Normative) Drawbar tests - Measurement of tire tread and track ... 20
Appendix C (Informative) Technical differences between this part and ISO 7899.1990 and the causes ... 21 Foreword
GB/T 3871 ?€?Agricultural tractors - Test procedures?€? is divided into 19 parts. Part 1. General requirements;
Part 2. Measurements of tractor parameters;
Part 3. Power tests for power take-off;
Part 4. Rear three-point linkage lifting capacity;
Part 5. Turning and clearance diameters;
Part 6. Determination of braking performance;
Part 7. Operators field of vision;
Part 8. Noise measurement;
Part 9. Power tests for drawbar;
Part 10. Low temperature starting;
Part 11. Suitability tests for hot atmosphere;
Part 12. Working tests;
-Part 13. Measurement of exhaust smoke;
Part 14. Partial power PTO - Non-mechanically transmitted power;
Part 15. Centre of gravity;
Part 16. Axle power determination;
Part 17. Engine air cleaner;
Part 18. Hydraulic power at tractor/implement interface;
- Part 19. Steering capability of wheeled tractors; This part is part 9 of GB/T 3871. This part modifies and adopts ISO 789-9.1990 Agricultural tractors -Test procedures - Part 1. Power tests for drawbar (English version). This part was redrafted in accordance with ISO 789-9.1990. Agricultural tractors - Test procedures ?€?
Part 9. Power tests for drawbar
1 Scope
This part specifies the test procedures for determining the power available at the drawbar on agricultural tractors of the wheeled, track-laying or semi-tracklaying type. The statement of the power rating of the drawbar is specified clause 6.4. 2 Normative references
The following part contains provisions which, through reference in this text, constitute provisions of this part. At the time of publication, the edition indicated was valid. All standards are subject to revision, parties who reach an agreement based on this part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies. GB/T 3871.3-2006 Agricultural tractors -Test procedures -Part 3. Power tests for power take-off (ISO 789-1.1990, MOD) JB/T 7282 Type and specifications of oil for tractors
3 Definitions
For the purposes of this part of GB/T 3871, the following terms and definitions apply. 3.1
Wheelbase
The distance between two planes which respectively pass the ground-contact center points of the front and rear wheels at the same side of the tractor and be respectively perpendicular to the longitudinal central plane and supporting plane. 3.2
5.4 Auxiliary equipment
For all tests, accessories such as the hydraulic lift pump or air compressor that can be disconnected without using tools (unless otherwise specified for special test) by the driver during normal operation shall be disconnected. Otherwise, they shall remain operated at minimum load. If the tractor is equipped with devices that create variable parasitic power losses, such as a variable speed cooling fan, intermittent hydraulic or electrical demands, etc., the device shall not be disconnected or status altered for test purposes. If it is practical for the operator to disconnect the device as outlined by the operator?€?s manual, it may be disconnected for test purposes, in which case this shall be recorded in the test report. During the test, if the power variations caused by these devices exceed ?? 5 %, it shall be recorded in the test report in terms of percent variation from the mean. 5.5 Test conditions
Such measurement values as torque or power do not need corrections for atmospheric conditions or other factors. Atmospheric pressure shall not be less than 96.6 kPa. If this is not possible because of altitude, it is allowed to adjust the carburettor or fuel pump, details of which shall be included in the report. Before beginning measurement at each test condition, the tractor shall reach stable operating conditions. 5.6 Fuel consumption
Arrange the fuel measurement apparatus so that the fuel pressure at the carburettor or the fuel injection pump is equivalent to that which exists when the tractor fuel tank is half full. The fuel temperature shall be comparable to that which occurs during full load operation for 2 h of the tractor when fuel is taken from the tractor fuel tank. Efforts shall be made to limit the temperature variations throughout the tests. The fuel consumption shall be measured when the tractor traverses a straight track for at least 20 m or for 20 s (whichever is longer). When using the volumetric method to measure the fuel consumption, it shall be based on the specific gravity of fuel at a certain temperature to calculate the fuel consumption mass per unit of work. Generally, the specific gravity of fuel at 15 ??C is used to calculate the volumetric data. When using the mass method to measure the fuel consumption, the fuel density (specific gravity) value at 15 ??C is used to calculate the volumetric data. 5.7 Ballasting and tire pressure
track-laying tractors, if the maximum pull occurs above 7% slip, it shall record the maximum drawbar pull as a footnote beneath the table giving drawbar performance figures. If the tractor has a hydrokinetic torque converter which can be locked out by the driver, carry out the test both with the torque converter in operation and with it locked out. If the tractor has a stepless variable transmission, carry out the test at six transmission ratios approximately equally spaced, including that at which maximum power is obtained. Record in the table the drawbar power, speed, wheel or track slip and fuel consumption as a function of drawbar pull. 6.2.2 Unladen tractor
This test determines the effective power provided by each gear to the drawbar when the unladen tractor is in a certain gear range. The test shall be carried out at least on each gear between the position one gear higher above the gear where the tractor can produce the maximum drawbar power and the position one gear lower than the gear where the tractor can produce the maximum drawbar power. 6.2.3 Ballasted tractor
This test determines the drawbar power of the ballasted tractor, the ballast shall be consistent with that provided in the technical parameters of the manufacturer, the test gear shall cover all forwarding gears from the minimum gear to the position one gear higher above that producing the maximum power. 6.3 10 h test
6.3.1 For the ballasted tractor as specified in clause 6.3, it shall be tested for 5 h as specified by the manufacturer at the gear as agreed by the testing party. This gear shall be the common gear for agricultural operation (such as ploughing) and the gear as far from the gear for the test of 6.3.2 as possible, the pull load applied shall be 75% of the drawbar force corresponding to the maximum drawbar power at the engine rated speed. It shall state the drawbar power, drawbar force, driving speed, slip ratio, and fuel consumption, etc., in the report. For the tractor equipped with the operator-controllable hydraulic torque converter, the 5 h test shall be carried out under the status where the hydraulic torque converter works, but it shall be within the limitations as specified in the instruction manual which is formally published by the manufacturer. If reaching the limit conditions, the test shall be carried out under the status where the hydraulic torque converter does not work. The test report shall respectively state the time and fuel consumption for the two parts of tests. be maintained stable during the test, the maximum drawbar power is the average value as recorded in the 2 h test period. If the power value measured each time deviates from the average value for more than 2%, the test shall be carried out again, if the retest result is same as before, the deviation shall be indicated in the report. 6.4.1.2 When performing engine varying speed test at full load conditions (also known as overload operation), all adjustments made on the tractor shall be same as that for the formal drawbar test and power take-off test. The slip ratio of the drive wheel shall be limited within 15%, the recorded data shall be same as that of other drawbar test, the gear for the test shall be same as the gear used in item 6.4.1.1. 6.4.1.2.1 The test shall be started from the maximum drawbar power at the engine rated speed, the drawbar load is increased gradually, to make the engine speed decrease gradually at the rate of 100 revolution per minute, the test is performed until the maximum drawbar pull is obtained, or otherwise until the test cannot be proceeded anymore as limited by the cooling capacity of the engine or torque converter (if any) or due to other limitations by the instructions of the manufacturer. If the tractor is fitted with the torque converter or torque enhancer with locking device, the test shall be carried out under status when the torque converter or torque enhancer work and do not work, respectively. If the tractor is equipped with the automatic gear transmission system, the test is performed until the automatic gear reduction occurs. 6.4.1.2.2 The partial load test is carried out at 75% of the drawbar pull at the engine rated speed. 6.4.1.2.3 The partial load test is carried out at 50% of the drawbar pull at the engine rated speed. 6.5 Statement of power rating
The power rating of the tractor is usually stated as power take-off power (clause 6.3 in GB/T 3871.3-2006). If the tractor is not fitted with a PTO capable of transmitting the full power of the engine, the power rating of the tractor shall be stated as the power measured at the drawbar.

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