On the interplay between the Engine Cooling Fan and Heat Exchanger for automotive AM band radiated emission measurement

Electrical interaction of Engine Cooling Fan (ECF) with Heat Exchanger would strongly influence the electromagnetic behavior, and hence the EMC test results. Motivation and Objective for extensive and exhaustive component-level Electro-Magnetic Compliance (EMC) tests relies on close correlation and harmony between the vehicle-level and component-level test results. In fact, comprehensive component-level tests are presumed to indicate that most stringent possible vehicle-level Electro-Magnetic Interference (EMI) scenario is exercised in order to relieve expensive vehicle-level tests. This paper examines a component-level test scenario for an ECF according to OEM approved EMC test-plan mandating non-conductive air-flow load, thus resulting in AM band (0.53 MHz - 1.7 MHz) radiated emission deviations. Radiated Emissions (RE) deviations root-cause studies and troubleshooting indicates Amplitude Modulated (AM) band radiated emission compliance would result when a grounded metallic heat-exchanger is used.