JT/T 1242-2019 English PDF (JTT1242-2019)

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JT/T 1242-2019: Performance requirements and test procedures for advanced emergency braking system of commercial vehicle
JT/T 1242-2019
TRANSPORTATION INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 03.220.20; 43.040.80
T 35
Registration number:
Performance requirements and test procedures for
advanced emergency braking system of commercial
vehicle
ISSUED ON: MARCH 15, 2019
IMPLEMENTED ON: APRIL 01, 2019
Issued by: Ministry of transport of PRC
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions, abbreviations ... 5 
4 General requirements ... 8 
5 Function requirements ... 10 
6 Environmental adaptability requirements ... 13 
7 Test procedures ... 14 
References ... 24 
Performance requirements and test procedures for
advanced emergency braking system of commercial
vehicle
1 Scope
This standard specifies the general requirements, functional requirements,
environmental adaptability requirements, test procedures for advanced
emergency braking systems of commercial vehicles.
The standard applies to advanced emergency braking systems installed on
commercial vehicles, where the test procedures are applicable to the normative
testing of advanced emergency braking systems in a closed field test
environment.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 19951-2005 Road vehicles - Test methods for electrical disturbances
from electrostatic discharge
GB/T 21437.2-2008 Road vehicles - Electrical disturbances from conduction
and coupling - Part 2: Electrical transient conduction along supply lines only
GB/T 21437.3-2012 Road vehicles - Electrical disturbances from conduction
and coupling - Part 3: Electrical transient transmission by capacitive and
inductive coupling via lines other than supply lines
GB/T 28046.1-2011 Road vehicles - Environmental conditions and testing
for electrical and electronic equipment - Part 1: General
GB/T 28046.2-2011 Road vehicles - Environmental conditions and testing
for electrical and electronic equipment - Part 2: Electrical load
GB/T 28046.3-2011 Road vehicles - Environmental conditions and testing
for electrical and electronic equipment - Part 3: Mechanical load
The length of path as travelled by the non-diffused light emitted by an
incandescent lamp which has a color temperature of 2700 K when its
illuminance is reduced to 5% of the initial value.
[GB/T 33577-2017, definition 3.14]
3.1.7
Adjacent lane
The travelling lane which shares the boundary of the lane as travelled by the
subject vehicle, the direction of which is opposite to the traveling direction of
the subject vehicle.
3.1.8
Clearance
The distance from the tail of the target vehicle to the head of the subject
vehicle.
3.1.9
Emergency braking phase
After the AEBS issues a brake command request to the subject vehicle, the
phase during which the subject vehicle starts deceleration at a speed of at
least 4 m/s2.
3.1.10
Collision warning phase
Before the emergency braking phase, the phase during which the AEBS
sends the driver an early warning of possible collisions in front.
3.1.11
Minimum start velocity
The minimum speed of subject vehicle when the AEBS starts the warning
and emergency braking function.
3.1.12
Relative velocity
The difference between the longitudinal speed of the subject vehicle and the
target vehicle, which is calculated by the use of the formula (1):
storage, working state of communication module, state of main power, state of
other devices connected to the AEBS host, etc.
The AEBS shall have a self-diagnosis function to prompt the driver and
generate fault code information in real time for faults that occur during operation.
4.6 Driver control and human-machine interface
The AEBS shall provide the driver with a human-machine interface to interact
with the driver. Provides warning information including at least two of audible,
visual, or tactile, braking information, operation, cessation, or fault state
information of the AEBS. The displayed information shall be clearly displayed
in direct sunlight and at night.
4.7 Driver intervention
When the subject vehicle is in the emergency braking phase, it shall be ensured
that the working state of AEBS is not affected by the driver's operation for brake
pedal.
4.8 AEBS function recovery and release
The AEBS shall automatically return to normal working state when the vehicle
is ignited. After the release of AEBS function, it shall use an optical warning
signal to alert the driver, prompting the driver that the AEBS is in the off/on state.
4.9 Brake constraints for emergency braking
Emergency braking shall not cause longer lock tire time than allowed by anti-
lock brakes or stability controls.
4.10 Brake light control
When AEBS implements automatic braking, the brake light shall illuminate at
the same time and remain lit for at least 0.5 s.
4.11 Data backup
4.11.1 For AEBS trigger event data, it shall perform local data backup and
remote data backup. The most recent storage time for local data backup shall
be not less than 48 h; the remote storage time shall be not less than 60 d.
4.11.2 AEBS trigger event data shall include at least the following information:
a) Operational behavior: The specific operational behavior generated by
AEBS, which shall include the information of not less than the activation
of collision warning function, activation of emergency braking function,
termination of collision warning function, termination of emergency
braking function;
b) Operational state: The state of the system when it responds to the
specified operational behavior, which shall include at least the normal
state, abnormal state, no response;
c) Timestamp: The time information that the system generates the
corresponding operational behavior.
4.12 Installation and use requirements
The AEBS system shall be installed and used in accordance with the
manufacturer's instructions for use, including AEBS calibration, minimum
starting speed, and applicable and non-applicable conditions.
5 Function requirements
5.1 Running speed
The AEBS shall operate normally at least within the range from a running speed
of 15 km/h to the maximum design speed under all load states of the vehicle.
5.2 Target detection area
5.2.1 The minimum detection distance of AEBS shall be not more than 2 m. The
maximum detection distance to the target vehicle shall be not less than 150 m.
The maximum detection distance to the pedestrians shall be not less than 60
m.
5.2.2 The AEBS's lateral detection width of the minimum detection level of the
target vehicle at the maximum detection distance position shall not be less than
3.75 m.
5.2.3 AEBS shall be capable of detecting the target vehicle on a bend which
has a radius of curvature not more than 250 m.
5.3 Collision warning
5.3.1 Warning time
If the TTC or ETTC is more than 4.4 s, the AEBS shall not issue a collision
warning.
5.3.2 Warning mode
When the AEBS detects a possible collision with a forward vehicle or pedestrian,
it shall be able to output an alarm of not less than two different levels. The level-
1 collision warnings shall be generated 1.4 s before the emergency braking
veh...