Honda Motor Co Ltd developed an electric-powered brake that controls the hydraulic pressure of its master cylinder with a ball screw.
The reaction force felt by the driver stepping on the brake pedal is created by using a simulator, and the reaction force from the master cylinder is not applied to the pedal.
It is the world's first "fully-electric-powered brake," which completely separates the pedal and the brake, Honda said. The company plans to use the brake for its compact electric vehicle (EV) and plug-in hybrid vehicle (PHEV) scheduled to be released in 2012.
With the new electric-powered brake, it becomes possible to finely control braking regardless of the force applied to the pedal by a foot. As a result, when electricity is regenerated by using a motor of, for example, an EV to slow down the vehicle, the amount of regenerated electricity can be increased by decreasing the brake's contribution to the slowdown. Compared with existing brakes, the amount of regenerated electricity increases by about 5%, Honda said.
The structure of the simulator looks like a master cylinder. It is a tandem type using two cylinders and actually contains oil. There is a channel that connects the master cylinder to the simulator's cylinder for fail-safe, but it is normally closed.