Electronic Transfer Case for 1990 Aerostar Electronic Four Wheel Drive

A transfer case was designed to utilize electronic control. It has a planetary interaxle differential for proportional torque split. An electromagnetic clutch is applied across the differential to enhance mobility when road coefficients allow single wheel or single axle traction loss. The need for clutch actuation is monitored by an electronic module and sensor system, that detects abnormal amounts of differentiation in the interaxle unit. Clutch actuation is signaled and controlled by the module, which is also electrically connected to the rear axle ABS brake system to eliminate any possible simultaneous function compatibility issues.

System emphasis is on foul weather mobility when negotiating highway and secondary roads. The family vehicle market was targeted and performance parameters were adjusted toward mobility and driver confidence to complete a given trip.