Brake System on Hybrid (Recuperation)

Brake System On Hybrid (Recuperation)







A special feature of the Cayenne S Hybrid is the highly efficient brake system, as it recovers part of the usually otherwise lost braking energy and renders it reusable for the drive. In addition to the hydraulic brake system on the front and rear axle used in the Cayenne S, which is actuated via a tandem brake master cylinder, the electric machine of the hybrid module contributes some of the braking performance in generator mode. The electric machine uses the mechanical kinetic energy from the moving vehicle's drive shaft here, whereby the rotor rotating with the shaft induces an electric current in the stator windings. The current is stored as electrical energy in the traction battery.

Brake pedal sensor

NOTE: To guarantee optimum recuperation, the installation position of the pedal sensor must be strictly observed.

The brake pedal sensor mounted on the pedals detects the degree of deceleration desired by the driver, which is duly input as a parameter in the operating strategy in order to generate braking torque in the electric machine. Recuperation is thus possible in the free travel area (pedal travel without conventional braking force) of the brake pedal before hydraulic brake pressure can actually be generated. The free travel was increased by 4 mm for more precise control.

Function

The brake pedal has a permanent magnet, which passes the pedal sensor when the brake is actuated. The sensor contains two Hall sensors within a measuring range, which cause a corresponding output voltage to be produced when the magnet is passed (Hall effect). Recuperation is controlled using this signal.