GB/T 33014.4-2025Road vehicles - Component test methods for electrical/electronic disturbances from narrowband radiated electromagnetic energy - Part 4: Harness excitation methods (English PDF)

6.1 BCI test method

6.1.1 General

The BCI method uses a current injection probe to directly couple the interference signal to the wiring harness for immunity testing. The injection probe is a current transformer through which the wiring harness of the device under test (DUT) passes. Carry out immunity tests by changing the test severity level and the frequency of the induced disturbance.

The following equipment is required.

-- Ground plane;

-- Current injection probe (probe set);

-- Current measurement probe (probe set);

-- Artificial Network (AN), High Voltage Artificial Network (HV-AN), Artificial

Mains Network (AMN) and Asymmetric Artificial Network (AAN);

-- Radio frequency (RF) signal generator with internal or external modulation capability;

-- Power amplifier;

-- Power measuring instrument. used to measure forward and reverse power;

-- Current measuring equipment.

6.1.2 Injection probe

The test requires one or a group of injection probes that cover the test frequency range to couple the test signal into the DUT. Regardless of the test load, the probe (probe group) shall be able to withstand the input power corresponding to the highest test level within the test frequency range.

The saturation of the injection probe due to the test level and the DUT operating current should be considered.

6.1.3 Current measurement probe

Tubular wave couplers are used to couple disturbance signals into the test harness. It shall be able to couple the test power into the wiring harness over the entire test frequency range and shall have a sufficiently high coupling rate and rated power.

6.2.3 50 ohm load resistor

The 50 ohm load resistor is used to match the output impedance of the tubular wave coupler, and its rated power shall be greater than or equal to the applied forward power.

6.2.4 DUT stimulation and monitoring equipment

See 6.1.4.

7.1 Ground plane

The ground plane shall be copper, brass, bronze or galvanized steel at least 0.5 mm thick.

The minimum width of the ground plane shall be 1 000 mm or the projected width of the entire test setup (DUT and accessory equipment, such as the wiring harness including power cords, simulated loads on the test table and AN, excluding batteries and/or power supplies) on the horizontal plane plus 200 mm, whichever is greater.

The minimum length of the ground plane shall be.

-- For the BCI closed-loop method with power limitation, the length shall be 1

500 mm, or the projected length of the entire test setup (DUT and accessory equipment, such as the wiring harness including the power cords, simulated loads on the test table and the AN, excluding batteries and/or power supplies) on the horizontal plane plus 200 mm, whichever is greater.

-- For all other test methods in this document, the length shall be 2 000 mm or the projected length of the entire test setup (DUT and accessory equipment, such as the wiring harness including the power cord, the simulated load on the test table and the AN, excluding the battery and/or power supply) on the horizontal plane plus 200 mm, whichever is greater.

The height of the ground plane (test bench) shall be (900±100) mm above the ground.

The ground plane shall be electrically connected to the shielded enclosure, and the DC resistance shall not exceed 2.5 mohm. The distance between the edges of adjacent grounding strips shall not be greater than 300 mm, and the maximum length-to-width ratio of the grounding strip shall be 7.1.

7.2 Power supply and AN

Each power cord of the DUT shall be connected to the power supply through AN.

Usually, the negative pole of the power supply is grounded. If the power supply used by the DUT is positively grounded, the layout in the test setup diagram shall be adjusted accordingly. The power supply shall be connected to the DUT through a 5 µH/50 ohm AN (see ISO11452-1 for schematic diagram). The number of ANs required depends on how the DUT is installed on the vehicle.

-- DUT far-end grounding (vehicle power return line larger than 200 mm). Use two ANs, one of which is connected to the positive pole of the power supply, and the other is connected to the power return line (see Appendix C).

-- DUT near-end grounding (vehicle power return line length not exceeding 200 mm). Use an AN to connect to the positive terminal of the power supply (see

Appendix C).

AN shall be installed directly on the ground plane, and its enclosure shall overlap the ground plane.

The power return line shall be connected to the ground plane (between the power supply and AN).

Each AN measurement port shall be terminated with a 50 ohm load that can absorb the RF power coupled to it.

The length of the power cord between the power supply and the simulated load shall be specified in the test plan and shall be kept as short as possible. Unless otherwise specified, the power cord between the power supply and the simulated load shall be placed directly on the ground plane.

7.3 DUT location

The DUT shall be placed on a non-conductive material with a low relative dielectric constant (epsilonr <= 1.4) at a distance of (50 ± 5) mm above the ground plane.

The DUT enclosure shall not be connected to the ground plane (except to simulate the actual vehicle structure).

The DUT surface shall be at least 100 mm away from the edge of the ground plane.

Except for the ground plane on which the DUT is placed, the distance between the DUT and any other metal parts (such as the walls of the shielded enclosure) should be at least

500 mm.

7.4 Location of test harness

Unless otherwise specified in the test plan, the length of the test harness between the

DUT and the simulated load shall be.

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