1 Scope
This standard specifies minimum stable speed test method for motor vehicles.
This standard is applicable to all kinds of motor vehicles. Automobile train may be implemented by reference to this standard.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of this document is applicable. For undated references, the latest editions of the normative documents are applicable to this standard.
GB/T 12534 "Motor Vehicles--General Rules of Road Test Method"
GB/T 12543 "Motor Vehicles--Acceleration Performance--Test Method"
GB/T 12677 Motor vehicles--Technical condition--Inspection methods
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
Minimum stable speed
It refers to minimum speed at which motor vehicles can travel steadily; this speed can ensure the motor not extinguished, transmitting mechanism not shuddered, motor vehicle in steady acceleration without a break and the corresponding engine speed not declined.
4. Test conditions
4.1 Measuring instruments
Requirements on measuring instruments for testing are as follows:
a) Velocity measurement instrument or speed travel measuring device: the precision shall be no less than 0.5%;
b) Revolution indicator: the precision shall be no less than 10r/min.
4.2 Test site
The testing shall be carried out on straightaway of flat hard surface (asphalt or cement); the length of the straightway shall be no less than 1km, the width no less than 8m and the longitudinal gradient no greater than 0.1% and the road surface shall be dry and clean.
4.3 Meteorological conditions
It shall be fine day or cloudy day without fog with relative humidity less than 95%, air temperature between 0~40℃ and air velocity no greater than 3m/s.
4.4 Test load
Test load shall be in accordance with those specified in GB/T 12543.
4.5 Tire pressure
Cold position inflation pressure of tire in testing shall meet the requirements on technical conditions of this vehicle and the error shall not exceed ±10kPa.
4.6 Thermal state of various assemblies of motor vehicle shall meet those specified in GB/T 12677.
4.7 Preparation of other test conditions and vehicles shall meet the relevant requirements in GB/T 12534.
