Standard No.:	GB/T 23920-2022
English Name:	Low-speed vehicles―Determination method of maximum speed
Chinese Name:	低速汽车 最高车速测定方法
Chinese Classification:	T54    Farm, livestock, by-product and fish vehicles
Professional Classification:	GB    National Standard
Issued by:	SAMR, SAC
Issued on:	2022-10-12
Implemented on:	2023-5-1
Status:	to be valid
Superseding:	GB/T 23920-2009 Tri-wheel vehicles and low-speed goods vehicles—Determination method of maximum speed
Language:	English
File Format:	PDF
Word Count:	5500 words
Price(USD):	165.0
Delivery:	via email in 1~3 business day

1 Scope This document describes the measurement method of the actual maximum driving speed of low-speed vehicles. This document is applicable to low-speed vehicles (hereinafter referred to as vehicles). 2 Normative References The contents in the following documents, through normative references, constitute indispensable provisions of this document. Where, for dated references, only the version corresponding to that date applies to this document; For undated references, the latest version (including all amendments) is applicable to this document. GB 21377-2015 Fuel Consumption Limits and Measurement Methods for Three wheel Vehicles 3 Terms and definitions There are no terms and definitions to be defined in this document. 4 Test conditions 4.1 Vehicles 4.1.1 The vehicle shall be refueled according to the instructions. 4.1.2 The fuel supply system shall be adjusted so that the engine power and speed meet the manufacturer's requirements. Any device that can cause changes in engine speed and/or vehicle running speed through adjustment shall be adjusted to the state that can make the engine speed and/or vehicle running speed reach the maximum. 4.1.3 The tires with the maximum outer diameter allowed by the manufacturer shall be used, and the inflation pressure shall be the tire pressure value recommended by the vehicle manufacturer when driving on the road. 4.1.4 The vehicle fuel tank shall be filled with fuel and the radiator shall be filled with coolant. 4.1.5 If there are windows in the cab of the test vehicle, the windows shall be closed, and the ventilation device in the cab shall be closed, unless the test vehicle has special requirements. In addition to the equipment necessary for the test and the daily control components of the vehicle, the lighting devices and auxiliary devices on the vehicle shall be turned off. 4.2 Measurement parameters, units and accuracy 4.2.1 The main measurement parameters, units and accuracy requirements of road test are shown in Table 1, 4.3 Determination of runway 4.3.1 The runway for measurement shall be a straight runway, and the measurement area shall be able to meet the measurement distance of at least 100 m when the vehicle runs at the actual maximum speed. 4.3.2 The runway for measurement shall be hard, clean, dry and flat asphalt pavement or concrete pavement with good adhesion coefficient. 4.3.3 The longitudinal gradient of the runway pavement shall not be greater than 2% and the transverse gradient shall not be greater than 3%. 4.3.4 The road acceleration area before entering the test section shall be long enough, flat and even, so as to ensure that the vehicle can stably maintain its maximum speed before reaching the measurement area. The length of the road leaving the test section shall ensure the safety of deceleration and departure. 4.4 Environmental conditions 4.4.1 The maximum difference between the air density in the test and the air density in the standard environment shall not exceed 10%. The atmospheric pressure during the test shall not be lower than 91kPa, the temperature shall not be lower than 273K, and the temperature shall not be higher than 313K (the test ambient temperature is ℃~40 ℃). The air density is calculated according to Formula (1). Where: Air density of the test environment, kg/m Air density of standard environment, d= 1.205kg/m: H Atmospheric pressure of test environment, in kPa; H Standard ambient atmospheric pressure, H= 100 kPa: T.=293 T Standard ambient temperature, (20 ℃) T: Test ambient temperature, in kelvin (K). 4.4.2 The road test shall be carried out under the environmental conditions that the relative humidity is not more than 95% and the wind speed is not more than 3m/s in the horizontal direction of the driving path, 4.5 Vehicle loading mass and load distribution 4.5.1 Determine the actual maximum running speed of the vehicle under no-load or maximum design total mass condition as required. 4.5.2 When loading according to the maximum design total mass, the loading mass shall be evenly distributed, and the load shall be firmly fixed to ensure that there is no shaking and jolting during the test; The quality shall not be changed due to humidity, loss and other conditions. To ensure that the size and distribution of the loading mass remain unchanged. The passenger (calculated as 65kg) can be replaced by a weight of the same mass. 5 Test method 5.1 Test preparation Before the test, the test vehicle shall be fully preheated to make the engine, power train, lubricating oil, etc. reach the specified stable temperature state. 5.2 Road test 5.2.1 Put the test vehicle into the highest forward gear, fully open the accelerator, reach the stable maximum speed, and then test drive into the measurement runway. 5.2.2 Conduct the test along the round-trip direction, and try to use the same path of the test section. 5.2.3 Measure the actual maximum driving speed of the vehicle in the round-trip direction within a distance of at least 100m. Record the time when the vehicle has traveled a distance of 100m 5.2.4 Conduct two consecutive measurements in the direction of heading and turning back. During the test, the driving speed change of the vehicle in the same direction shall not exceed 2%. Otherwise, the number of tests shall be increased, and the value with greater divergence shall be rounded off. 5.2.5 Fill in the relevant measured values required in Table A.1 of Appendix A and calculate the average vehicle speed for each round trip. 5.2.6 Take the higher of the average speed of the vehicle for two consecutive trips as the actual maximum driving speed of the vehicle. 5.3 Drum test bench test 5.3.1 For the test vehicle, the equivalent inertia of the chassis dynamometer shall be set according to the requirements of A5.1 and A.6 in GB 21377-2015, and the driving resistance shall be set according to the requirements of Appendix B. 5.3.2 Place the vehicle on the chassis dynamometer and protect it properly. The vehicle is in the highest forward gear, and the maximum driving speed is reached by fully opening the accelerator. 5.3.3 Measure the actual maximum driving speed of the vehicle within a distance at least equivalent to 100m. Record the time when the vehicle travels 100m on the test bench, and directly read the average value of this time as the maximum speed value. 5.3.4 Carry out two consecutive measurements. Fill in the relevant measurements required in Table A.2 of Appendix A. 5.3.5 Take the higher of the two vehicle speeds as the actual maximum driving speed of the vehicle. 5.3.6 If there is any doubt about the drum test bench test, the road test can be used for retesting. 5.4 Determination report Appendix A (normative) Measurement report of actual maximum driving speed The measurement report shall at least include the following contents: a) Executive standard (No. of this document): b) Vehicle type and model: c) Vehicle manufacturer: d) Vehicle Identification Number (VIN) and engine number: e) Engine type, model, nominal power (kW), nominal speed and actual maximum speed (r/min): Drive train type: (J g) Vehicle loading status and loaded mass at the time of determination (kg) h) Specification and rolling radius of front and rear tires; i) Tyre pressure (kPa): j) Road test/drum test bench test: k) Pavement condition and material of runway during measurement (if applicable); (1) Runway longitudinal gradient and transverse gradient (if applicable); m) Drum radius (if applicable); n) Rotational inertia of drum (if applicable); Maximum design vehicle speed: (0 p) Weather conditions, including wind speed (m/s), wind direction, air pressure (kPa), air temperature (℃) and relative humidity (%); q) Determine the actual maximum driving speed according to Table A.1 and Table A.2. The speed v calculated each time shall be rounded to 2 decimal places, and the average speed of the round trip test shall be rounded to 1 decimal place. Annex B (normative) Setting of running resistance on chassis dynamometer

1 Scope 2 Normative References 3 Terms and definitions 4 Test conditions 5 Test method Appendix A (normative) Measurement report of actual maximum driving speed Annex B (normative) Setting of running resistance on chassis dynamometer