GB/T 47246-2026Technical specification for the electronic functions of child restraint systems for power-driven vehicles (English PDF)

3.1 Child Restraint System; CRS; Child Seat

A device designed to reduce injury to the occupant - by restricting the movement of the child's body - during a vehicle collision or sudden deceleration, while maintaining the child occupant in a seated or reclining position. [Source: GB 27887-2024, 3.1]

3.2 Rigid Fixture for the Child Restraint System; ISOFIX

An internationally standardized system for connecting a child restraint system to a vehicle using two lower anchor points on the vehicle, two corresponding rigid connectors on the child restraint system, and a device to limit the rotation of the child restraint system. [Source: GB 27887-2024, 3.4]

3.3 Test Dummy

A dummy used in testing to simulate a child.

NOTE: Q-series or P-series dummies are included.

3.4 Electronic Component

A component that primarily relies on the movement of electrons in a vacuum, gas, or semiconductor to conduct electricity. [Source: GB/T 19865-2024, 3.5.5, with modifications]

3.5 Working Voltage

The voltage required to maintain the proper functioning of the electronic components of the child restraint system.

NOTE: Effects of transient voltages are disregarded.

3.6 Close-to-the-Ear Device

A sound-emitting device located on the child restraint system, close to the child's ears.

NOTE: A loudspeaker positioned in the headrest of the child restraint system.

3.7 Heating Device

The electronic component used for heating in a child restraint system.

3.8 Wired Communication

The method of communication between the child restraint system and the terminal via a transmission medium, such as a conductor or cable.

3.9 Wireless Communication

The method of communication between the child restraint system and the terminal that does not utilize conductors or cables.

4.1 Classification by Communication Function

Child restraint systems are classified into the following types based on whether they possess communication functions.

a) Class I: Child restraint systems with communication functions. The communication functions of Class I child restraint systems may utilize, but are not limited to, the following methods:

- Wired communication: e.g., via Controller Area Network (CAN) bus, Universal Serial Bus (USB), Ethernet, Local Interconnect Network (LIN) bus, etc.;

- Wireless communication: e.g., Bluetooth Low Energy (BLE), Wireless Local Area Network (Wi-Fi), 4th or 5th generation mobile communication technology (4G/5G), short-range wireless communication technology (e.g., NearLink), etc.

b) Class II: Child restraint systems with electronic functions but without communication functions.

4.2 Classification by Power Supply Method

Child restraint systems are classified into the following types based on their power supply method.

a) Battery-powered: Child restraint systems powered by dry-cell batteries or rechargeable batteries;

b) Externally powered: Child restraint systems that draw power from the vehicle or an external power source via a power interface;

c) Hybrid-powered: Child restraint systems that utilize both of the above power supply methods.

5.1 Environmental Adaptability Requirements

5.1.1 Environmental adaptability in static state

Under the following environmental conditions, with the child restraint system in a static (powered-off) state, a temperature cycling test shall be conducted in accordance with the provisions of 6.3.1.1. After returning to the environmental conditions specified in 6.1, an inspection shall be performed in accordance with 6.3.1.2; the electronic functions of the child restraint system shall operate normally.

a) Ambient temperature: -20°C to 85°C;

b) Relative humidity: 30% to 90%.

5.1.2 Operating environment adaptability

Under the following environmental conditions, a temperature cycling test shall be conducted in accordance with 6.3.1.1, followed by an inspection in accordance with 6.3.1.3; a damp-heat cycling test shall be conducted in accordance with the provisions of 6.3.2. During and after the tests, the electronic functions of the child restraint system shall operate normally.

a) Ambient temperature: -10°C to 60°C;

b) Relative humidity: 30% to 90%.

5.2 Basic Functional Requirements

5.2.1 Low-battery warning function

Battery-powered child restraint systems shall be equipped with a low-battery warning function.

A low-battery warning test shall be conducted in accordance with the provisions of 6.4.1. When the voltage falls below the specified limit, the child restraint system shall alert the users to the insufficient power level and prompt them to replace or recharge the battery; the form of the alert is not restricted.

5.2.2 Anti-pinch function

Child restraint systems equipped with electric adjustment functions shall feature an anti-pinch function. Testing for this function shall be conducted in accordance with the provisions of 6.4.2; the child restraint system shall stop or reverse movement when encountering resistance (not exceeding 100 N) and shall issue a warning. The form of the warning is to be determined by the manufacturer but must be specified in the instruction manual. This article does not apply to electric adjustment functions that operate in incremental steps solely through user tapping; nor does it apply if the electric adjustment functions of the child restraint system cannot be executed while a child is seated.

NOTE: Electric adjustment functions include electric seat rotation, electric backrest angle adjustment, electric headrest extension/retraction, etc.

5.2.3 Child restraint status detection function

For child restraint systems equipped with functions such as child occupancy detection or detection of buckle locking status for full-body harness-style child restraint straps, the child restraint status detection test shall be conducted in accordance with the provisions of 6.4.3; a notification shall be provided when the status of the corresponding function changes, in any form.

5.2.4 Installation warning function

For child restraint systems equipped with installation detection functions, the installation warning test shall be conducted in accordance with the provisions of 6.4.4.4; a notification shall be provided when the status of the corresponding function changes, in any form.

NOTE: Installation detection functions include ISOFIX installation detection, support leg installation detection, top tether installation detection, etc.

5.2.5 Acoustic requirements for sound-emitting devices

When conducting the sound pressure test in accordance with the provisions of 6.4.5, the A-weighted equivalent sound pressure level (LpAeq) of the sound measured from close-to-the-ear devices shall not exceed 65 dB; the A-weighted equivalent sound pressure level (LpAeq) of the sound measured from sound-emitting devices other than close-to-the-ear devices shall not exceed 85 dB.

5.3 Basic Communication Requirements

5.3.1 Communication functions and data transmission

Class I child restraint systems shall meet the following requirements.

a) They shall be capable of communicating with a mobile terminal (e.g., a mobile phone or in-vehicle system) or a cloud server; the design of communication methods and protocols shall comply with Appendix A;

b) The communication function shall not interfere with the network communication of the connected mobile terminal itself (e.g., the mobile terminal's cellular network);

c) Data transmission tests shall be conducted via the debugging port in accordance with the provisions of 6.5.1, and the packet loss rate and error rate for communication data shall not exceed 0.1%.

5.3.2 Left-behind warning

For child restraint systems equipped with a child-left-behind warning function, the left-behind warning test shall be conducted in accordance with the provisions of 6.5.2. When a child is left in the child restraint system, the device connected to the child restraint system (e.g., a mobile terminal or cloud server) shall issue a warning. The form of the warning is to be determined by the manufacturer but must be specified in the instruction manual. When the child restraint system is connected to a mobile terminal (e.g., a mobile phone), a warning shall be issued before the distance between the mobile terminal and the child restraint system exceeds 35 m.

5.4 Structural Safety Requirements

5.4.1 Battery installation error prevention requirements

Child restraint systems with removable batteries shall feature a design that prevents incorrect battery polarity installation or ensures that the system cannot be powered on if the battery is installed with reversed polarity.

5.4.2 Injury from electronic component breakage

After each dynamic test conducted in accordance with the provisions of GB 27887, the electronic components and their housings of the child restraint system are permitted to deform but shall not fracture or break apart and become detached.

5.5 Electrical Safety Requirements

5.5.1 Power supply requirements

The rated voltage (U) for each power supply mode of the child restraint system shall be specified in the instruction manual and on the product marking, and shall meet the following requirements.

a) The rated supply voltage shall not exceed 24 V; the normal working voltage range and the overvoltage test voltage shall be as specified in Table 1;

b) When the power supply test is conducted in accordance with the provisions of 6.7.1, the child restraint system shall operate normally within the normal working voltage range corresponding to its rated voltage; when the overvoltage test voltage is applied, […]