Braking Systems for High Performance Electric Vehicles - A Design Study

Any young person who has taken delight in playing with toy slot cars knows that the world of racing and the world of electric cars has been intertwined for a long time. And anyone who has driven a modern performance electric vehicle knows that the instant acceleration, exhilarating speeds, and joy of driving of slot cars is reflected in these full sized “toys”, with the many more practical benefits that come from being full-sized and steerable. There is strong foreshadowing of a vibrant future for performance cars in some of the EV’s on the market now and in the near future, some offering “ludicrous” acceleration, and others storied nameplates with performance to match. The ease at which powerful electric drives can capably hurtle a massive vehicle around the track at high speeds, combined with the potential for the same electric drives to exert powerful regenerative braking, creates a very interesting situation for brake engineers. What wins out in the end - raw power or regenerative braking? What can change in the course of a track session that would affect how braking energy is shared between the friction brake system and electric drives? How does this affect the brake system design and specification for a performance EV? This paper will walk through a design study to explore these questions, and in the course of doing so, will also explore some methodologies for engineering the brake systems for high performance EV’s that will include Driver In the Loop (DIL) simulations, brake system performance simulations, and inertia dynamometer testing, as well as “simple but sufficient” means of accounting for the drive and regenerative braking system behavior.