GB/T 12678-1990 in English

《GB/T 12678-1990汽车可靠性行驶试验方法》由TC114（全国汽车标准化技术委员会）归口，主管部门为工业和信息化部。
本标准规定了汽车可靠性行驶试验方法。本标准适用于各类汽车的定型和质量考核时的整车可靠性行驶试验。

1 Subject Content and Application Scope

This standard specifies reliability running test method for automobiles.
This standard is applicable to reliability running test for complete vehicle during finalization and quality assessment of automobiles.

2 Normative References

GB 7031 Vehicle Vibration - Describing Method for Road Surface Irregularity
GB/T 12534 Motor Vehicles - General Rules of Road Test Method

3 Terms

3.1 Routine reliability test
Reliability test carried out according to certain regulations under highway and ordinary road conditions.
3.2 Quick reliability test
Reliability test with certain quick coefficient carried out on road in proving ground.
3.3 Maintenance after failure
Maintenance carried out after automobiles break down.
3.4 Preventive maintenance
Maintenance carried out according to periods and items specified in operation instructions of automobiles.
3.5 Potential failure
Failure that has existed, but has not been discovered or that is discovered in the process of preventive maintenance and overhauling.
3.6 Equivalent failure number
The number of general failures converted from failures at various levels with certain coefficient according to their hazardness.

4 Test Conditions

4.1 Loading mass
Loading mass is in accordance with requirements of Article 1 in Chapter 3 of GB/T 12534.
4.2 Test road
4.2.1 Routine reliability test road
Pavement grade of routine reliability test road is in accordance with those specified in Table 1 of GB 7031.
4.2.1.1 Plain road
Rolling plain road with pavement smoothness of Grade C or above, maximum gradient less than 5% as well as broad, straight and even pavement and good field of vision where running distance of automobiles can be greater than 50 km at relatively high speed.
4.2.1.2 Bad road
Road with solid subgrade, uneven pavement, obvious washboard wave and uniform fish-scale pit as well as with pavement unevenness of Grade E or below. Where test vehicles are running on such pavement, they shall be subject to relatively strong vibration and distortion load, but not oversize impact.
4.2.1.3 Mountain road
Its average gradient is greater than 4 % and maximum gradient is 15%; continuous slope length is greater than 3km and the pavement smoothness is Grade C.
4.2.1.4 Urban road
Main traffic artery and streets with pavement smoothness of above Grade C in large and medium-sized cities.
4.2.1.5 Roadless section
Wilderness areas where vehicles are rarely running, such as desert, grassland, muddy ground, bush, snowfield and water beach.
4.2.2 Proving ground reliability test road
Generally, proving ground reliability test road shall include special reliability road with fixed shape (such as stone road, pebble road, fish-scale pit road, washboard road, twisted road, bump road, sand pool, water pool and saltwater pool), high-speed track, ramp and sand-clay road.
4.3 Weather
Generally, multiple weather conditions shall be selected to carry out tests. Tests shall be carried out under corresponding special meteorological conditions (such as severe cold, humid and hot conditions) for automobiles used in special areas or for special purposes
4.4 Test instrument and equipment
Running condition recorder, meteorograph, stopwatch, semiconductor thermometer, engine speed indicator, gradiometer and pavement meter).
4.5 Tyre pressure, fuel, lubricating oil (grease) and brake fluid are in accordance with requirements of Articles 2 and 3 in Chapter 3 of GB/T 12534.

1 Subject Content and Application Scope
2 Normative References
3 Terms
4 Test Conditions
5 Preparation of Test Vehicles
6 Test Methods
7 Test Data Treatment and Evaluation Indicator Calculation
8 Test Report
Appendix A (Additional) Records and Statistics
Appendix B (Informative) Due Multiplier Coefficient of MTBF during Calculation of Lower Confidence Limit for Timing Tail-cutting
Additional Explanation