GB/T 23920-2022 PDF in English
GB/T 23920-2022 (GB/T23920-2022, GBT 23920-2022, GBT23920-2022)
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Low-speed vehicles - Determination method of maximum speed
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GB/T 23920-2022: PDF in English (GBT 23920-2022) GB/T 23920-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 65.060
CCS T 54
Replacing GB/T 23920-2009
Low-speed vehicles - Determination method of maximum
speed
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: MAY 01, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Test conditions ... 5
5 Test methods ... 8
Appendix A (Normative) Measurement report of the actual maximum running speed
... 10
Appendix B (Normative) Setting of running resistance on chassis dynamometer ... 12
Low-speed vehicles - Determination method of maximum
speed
1 Scope
This document describes the determination method of actual maximum speed of low-
speed vehicles.
This document applies to low-speed vehicles (hereinafter referred to as vehicles).
2 Normative references
The following documents are normatively referenced in this document and are
indispensable for its application. For dated references, only the version corresponding
to that date is applicable to this document; for undated references, the latest version
(including all amendments) is applicable to this document.
GB 21377-2015, Tri-wheel vehicles - Limits and measurement methods for fuel
consumption
3 Terms and definitions
No terms and definitions need to be defined in this document.
4 Test conditions
4.1 Vehicles
4.1.1 Vehicles shall be filled with fuel according to the regulations in the instructions
for use.
4.1.2 The adjustment of the fuel supply system shall be such that the engine power and
speed comply with the manufacturer’s regulations. Any device that can cause changes
in the engine speed and/or vehicle speed through adjustment shall be adjusted to the
state that enables the engine speed and/or vehicle speed to reach the maximum.
4.1.3 The tire with the maximum outer diameter allowed by the manufacturer shall be
used; the inflation pressure shall be the tire pressure value recommended by the vehicle
manufacturer for road driving.
4.3.4 The accelerating zone of the road before entering the test road section shall be
long enough, and shall be flat and even in slope, so as to ensure that the vehicle can be
kept at the maximum speed stably before reaching the test zone. The length of the road
leaving the test road 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 91 kPa; the temperature shall not be lower than 273 K, and
not higher than 313 K (where the test environmental temperature is 0 °C ~ 40 °C).
Calculate the air density according to Formula (1).
Where:
dT – air density of the test environment, in kilograms per cubic meter (kg/m3);
d0 – air density of the standard environment, d0 = 1.205 kg/m3;
HT – atmospheric pressure of the test environment, in kilopascals (kPa);
H0 – atmospheric pressure of the standard ambient, H0 = 100 kPa;
T0 – temperature of the standard environment, T0 = 293 K (20 °C);
TT – temperature of the test environment, in Kelvins (K).
4.4.2 The road test shall be carried out under environmental conditions where the
relative humidity is not greater than 95%, and the wind speed in the horizontal direction
of the driving path does not exceed 3 m/s.
4.5 Vehicle loading mass and load distribution
4.5.1 As required, measure the actual maximum running speed of the vehicle under no-
load or maximum design total mass state.
4.5.2 When loading at the maximum design total mass, the loaded mass shall be evenly
distributed, and the loaded object shall be fixed firmly to ensure that there is no shaking
or overturning during the test; its mass shall not be changed due to changes in conditions
such as humidity and loss, so as to ensure that the size and distribution of the loaded
mass remain unchanged. The occupant (calculated as 65 kg) can be replaced by the
weight of the same mass.
5 Test methods
5.1 Test preparation
Before the test, the test vehicle shall be fully preheated so that the engine, transmission
system, lubricating oil, etc. reach the specified stable temperature state.
5.2 Road test
5.2.1 Put the test vehicle in the highest forward gear, fully open the accelerator to reach
a stable maximum speed, and try to drive into the test runway.
5.2.2 Carry out the test along the to-and-from direction, and try to use the same path of
the test section.
5.2.3 Along the to-and-from direction, measure the actual maximum running speed of
the vehicle within a distance of at least 100 m. Record the time for the vehicle to travel
a distance of 100 m.
5.2.4 Carry out two consecutive measurements in the to-and-from direction, and the
speed change of the vehicle in the same direction during the test shall not exceed 2%.
Otherwise, the number of tests shall be increased, and the values with far deviations
shall be discarded.
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 to-and-from trip.
5.2.6 Take the larger of the average vehicle speeds of two consecutive to-and-from trips
as the measured actual maximum running speed of the vehicle.
5.3 Drum dynamometer test
5.3.1 For the test vehicle, an equivalent inertia of the chassis dynamometer shall be set
according to the requirements of A.5.1 and A.6 in GB 21377-2015, and the running
resistance shall be set according to the requirements of Appendix B.
5.3.2 Place the vehicle on the chassis dynamometer, with proper protection. Put the
vehicle in the highest forward gear and fully open the accelerator to reach the maximum
speed.
5.3.3 Measure the actual maximum speed of the vehicle within a distance equivalent to
at least 100 m. Record the time when the vehicle travels a distance of 100 m on the test
bench, and directly read the average value during this period as the maximum speed
value.
5.3.4 Take two consecutive measurements. Fill in the relevant measurements required
in Table A.2 of Appendix A.
Appendix A
(Normative)
Measurement report of the actual maximum running speed
The measurement report shall at least include the following:
a) implementation standard (number of this document);
b) vehicle type and model;
c) vehicle manufacturer;
d) vehicle identification number (VIN) and engine number;
e) engine type, model, calibrated power (kW), calibrated speed and actual maximum
speed (r/min);
f) drive system type;
g) vehicle loading state and loading mass (kg) at the time of measurement;
h) front and rear tire specifications and rolling radii;
i) tire pressure (kPa);
j) adopted road test/drum dynamometer test;
k) runway surface conditions and runway material at the time of measurement (when
applicable);
l) longitudinal gradient and transverse gradient of the runway (when applicable);
m) drum radius (when applicable);
n) moment of inertia of the drum (when applicable);
o) maximum design speed of the vehicle;
p) weather conditions, including wind speed (m/s), wind direction, air pressure (kPa),
temperature (°C), relative humidity (%);
q) the actual maximum running speed determined 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 one to-and-from trip of the road test shall be rounded to 1
decimal place.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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