Since MR fluids have a very high yield stress they can be used to control the transmission of torque in rotating machinery too. For example, they may be used in an automotive powertrain to transmit torque from the engine to the transmission and the vehicle. The following figure (fig 9) shows a 3D schematic of the possible location of the MRF clutch in an automobile. The MR sponge clutch may be used to provide launch control of an automobile thereby achieving smooth vehicle launch.
Fig 9 A 3-D cut view of the MR sponge clutch
Here the MR clutches operate in shear mode. Once again MR sponge clutch can be used here due to its advantages as mentioned before. Since the MR sponge device can give about 5 N/cm2 of force appropriate clutches can be designed based on the requirement of the application. The designed clutch is shown in the figure below. The MRF clutch thus may replace the existing torque converters and therefore help increase the fuel economy. The problem of centrifugal force effect has also been analyzed thereby estimating the clutch performance at higher speeds.
Fig 10 Assembled MRF sponge clutch
Fig 11 MR Sponge Clutch Testing
Fig 12 MRF sponge clutch test results