Vehicle behavior during braking in a turn is important for vehicle stability and controllability. Behavior of a four wheel drive (4WD) vehicle is different from that of a two wheel drive (2WD) vehicle due to larger moment of inertia of driveline and restraint condition between front and rear anxle.
Theoretical analysis and experimental study were conducted on the behavior of three typical 4WD systems: (1) 4WD with center differential; (2) 4WD with directly connected front and rear axles; (3) 4WD with viscous coupling (viscous transfer type).
In order to confirm the validity of the simulation, vertical, longitudinal and lateral forces working on four wheels during braking in a turn were measured by a six-component wheel load cell installed on each wheel.
This study clarifies that the influence of suspension characteristics and brake force distribution is important in 4WD vehicles with center differential and the influence of suspension characteristics is important in directly connected 4WD vehicles and 4WD vehicles with viscous coupling.