Automotive EMC testing is the process of measuring the electromagnetic compatibility (EMC) of a car and its components. Every part from car radios to engines need to be tested to see how their electromagnetic fields interact and determine whether any part generates electromagnetic interference (EMI). EMC testing is now more important than ever as automotive RF design grows in complexity and manufacturers integrate 4G, WiFi and Bluetooth technology into their cars. Emerging markets like electric and automated cars also contribute to this increase in design sophistication. A dashboard is full of active components, which, as they communicate with control systems and each other, produce RF noise and emissions, potential sources of EMI. EMC compliance is a pillar of modern automotive manufacturing, essential to passenger safety, driving performance and ultimately revenue.
Automotive EMC Test Equipment
Cars require EMC testing for both EMI immunity and EMI emissions levels, which divide further into four different varieties: radiated emissions, conducted emissions, radiated immunity and conducted immunity tests.
Immunity testing will determine the radiated and conducted susceptibility of active communications components, including microprocessors installed in control and entertainment systems. Circuit design is one of the essential factors in to shielding against EMI, and wire routing can either directly cause EMI or affect the EMC path.
Transient Immunity Generators
Automotive transient immunity generators test a device's conducted susceptibility by simulating transients, dramatic fluctuations in current and voltage, in accordance with standards like IEC-61000-4 and ISO 7637.
RF power amplifiers test cars and automotive components for their immunity to radiated EMI. An amplifier will fulfill MIL-STD 461G RS103 & RS105, standards for radiated susceptibility testing.
Emissions testing in automobiles focuses on measuring EMI created by broadband and narrowband emissions. Broadband EMI occurs in ignition components and other parts which tend to "arc and spark," generating broadband radiated emissions. Active electronics in a car, such as electric motors, produce narrowband emissions.
LISNs, line impedance stabilization networks, will detect conducted emissions generated by active components like electric motors with respect to MIL-STD 461G CE101 & CE102 standards. LISNs help capture repeatable measurements of RF noise at the LISN measurement port.
EMI receivers detect the transient signals and spurious emissions a part generates, fulfilling radiated emissions standards like MIL-STD-461G RE102. An EMI receiver is especially effective in applications where fast acquisition rates are desirable, and often reveals RF anomalies that may otherwise go undetected.
Automotive EMC Test Standards
- ISO 7637-1 | General considerations for electrical disturbances from conduction & coupling
- ISO 7637-2 | Transient conduction along supply lines
- ISO 7637-3 | Transient conduction via capacitive/inductive coupling via non-supply lines
- ISO 11451 | Narrowband radiated electromagnetic energy in vehicles
- ISO 11452 | Electrical disturbances in components
- ISO 16750-2 | Electrical load testing
- CISPR 12 | Radio disturbances in off-board receivers
- CISPR 25 | Radio disturbances in on-board vehicles, boats, other devices
- SAE J551 | EMC of vehicles, boats and machines
- SAE J1113 | EMC of vehicle, boat and machine components
- + Many more OEMs