Review Magnetorheological Fluids and their Automotive Applications

– Magnetorheological fluids (MRF) are smart materials whose rheological properties can be rapidly and reversibly controlled by applying a magnetic field. This review explores the fundamental composition and operating principles of MRF and highlights their transformative potential in automotive systems. Composed of carrier fluids, magnetic particles, and stabilizing additives, MRFs exhibit variable viscosity that can transition from a liquid to a semi-solid state under magnetic influence. The paper classifies the operational modes of MRF-based actuators—flow, shear, and squeeze modes—and discusses their respective applications in brakes, clutches, and dampers. Particular emphasis is placed on recent advances in MR brake and clutch designs tailored for motorcycles, wheelchairs, and active suspension systems. Similarly, MR dampers are shown to significantly improve ride comfort, driving stability, and vibration control in vehicle suspensions and seat systems. The review underscores the advantages of MRF technology, such as fast response time, low power consumption, and fail-safe operation, while acknowledging design challenges related to magnetic circuit integration. Ultimately, the study affirms the growing relevance and adaptability of MRFs in the evolution of smart automotive systems.