GB/T 38750.2-2020Reciprocating internal combustion engine energy efficiency evaluating specifications—Part 2:Gasoline engines (English PDF)

3.1 Light-duty vehicle

M1, M2 and N1 vehicles (including light passenger vehicles and light commercial vehicles) whose maximum total mass does not exceed 3 500 kg.

5.1 Test conditions

The accuracy and measurement position of the measuring instrument of the light-duty vehicle gasoline engine are in accordance with the provisions of

Chapter 4 in GB/T 18297-2001; the general test conditions are in accordance with the provisions of Chapter 6 in GB/T 18297-2001; the accessories that are attached to the engine during the measurement shall be in accordance with the regulations in Chapter 7 of GB/T 18297-2001; the calibration value of the gasoline engine parameters is consistent with the calibration value during emission measurement. The accuracy of general gasoline engine measuring instruments and equipment is in accordance with the requirements of Appendix

BA in GB 26133-2010; the resistance of the intake and exhaust system shall be within 110% of the upper limit that is specified by the manufacturer; the accessories for the general gasoline engine net power measurement are in accordance with Appendix A.

5.2 Test fuel

The fuel for the testing of light-duty vehicle gasoline engines is in accordance with the provisions of the test fuel in the current national valid light-duty vehicle pollutant emission standards. The fuel for the testing of general gasoline engines shall be in accordance with the gasoline that is specified in GB 17930, or in accordance with the reference gasoline that is specified in current valid light-duty vehicle pollutant emission limit and measurement method national standards, or uses ethanol gasoline that complies with GB 18351-2017.

The two-stroke general gasoline engine fuel/lubricant mixing ratio shall meet the manufacturer's recommended value and be recorded.

5.3 Test cycle

5.3.1

Light-duty vehicle gasoline engines measure the fuel consumption per hour under the five working conditions that are specified in Table 4.

Table 4 -- Test cycle for the average fuel consumption rate test of the light-duty vehicle gasoline engines under 5 working conditions

Gasoline engine working condition number

Gasoline engine speed r/min

Average effective pressure of gasoline engine

MPa

Idle speed […]

5.4 Test measurement

After the light-duty vehicle gasoline engine reaches the steady state that is specified by the manufacturer under each test working condition, at least measure power, torque, speed, fuel consumption per hour, ambient temperature and pressure twice, and take the average value as the measured value under this working condition. The difference between the two measured values of torque and fuel consumption per hour does not exceed 2%. When measuring the data, the difference between the engine operating speed and the selected speed does not exceed 1% or ±10 r/min.

The general gasoline engine G1, G2 or G3 test cycle shall be implemented in order of increasing working condition number. The sampling time of each working condition shall be at least 180 s; the fuel consumption shall be measured and recorded in the last 120 s of the respective sampling period.

Before the measurement of each working condition, it shall last long enough, so as to allow the engine to reach a thermally stable state. The thermal stability criterion is proposed by the manufacturer. If it is not proposed, it shall meet the level that the spark plug gasket temperature change value is less than 10 °C within 3 min. The duration of the working condition shall be recorded and reported.

5.5

Calculation of average fuel consumption rate of light-duty vehicle gasoline engine under 5 working conditions

When the gasoline engine is measured in a non-standard environment, its fuel consumption rate is not corrected.

The average fuel consumption rate g e of the gasoline engine under 5 working conditions is calculated according to Formula (1):

Where:

g e – average fuel consumption rate under 5 working conditions, in grams per kilowatt hour [g/(kW·h)];