Front-and-rear-wheel-independent-drive type electric vehicle (FRID EV) with the outstanding driving performance suitable for next-generation adavanced EVs

Abstract

A front-and-rear-wheel-independent-drive-typeelectric vehicle (FRID EV) is being developed as the next generation EV with optimum characteristics compatible in driving performance and safety. The FRID EV development work has included studying the driving performance and safety of all types of propulsion systems. Since the FRID EV has propulsion systems which can control the driving and braking torques of the front and rear wheels independently, various outstanding and indispensable functions are produced. Three functions which EVs developed until now could not have are shown here experimentally. The first is the failsafe function under which vehicles continue running without any unexpected sudden stops, even if one of the propulsion systems fails. The second is the function for performing efficient acceleration and deceleration on all roads by suitably distributing the driving or braking torques to the front and rear wheels according to the road surface conditions. The third is the function for ensuring safe running on bad roads, i. e., low μ -roads like frozen roads, by simultaneously controlling slip ratios of the front and rear wheels in consideration of load movement. These are functions are unique to the FRID EV and they have not be realized previously in any gasoline engine-powered car, hybrid car or conventional electric vehicle.