Conventional Mode

The conventional mode is the mechanical fallback level of the hybrid brake system. In this mode, there is again a mechanical connection between the brake pedal and brake servo. Thus the driver can generate a brake pressure in the hydraulic brake system just as in conventional vehicles with brake power assistance, safely decelerating the vehicle. In conventional mode, regenerative braking is no longer possible. Instead, the full braking power is provided by the hydraulic brake system.

If the driver presses the brake pedal in conventional mode, the solenoid valve in the active brake servo is not activated. Thus the push rod initially does not move. As a result, when the brake pedal is pressed, the gap between the bolt and limit position at the end of the push rod is closed, and the mechanical connection mentioned above is created.

From the driver's perspective, this manifests itself as an increase in the free travel. The driver feels hardly any counterforce until the bolt touches the limit position. In conventional mode, the solenoid valve in the shut-off unit is open. Thus the brake fluid in the shut-off unit can flow upwards into the chamber. There, a moving piston is located that can move upwards against a spring force. The spring in the shut-off unit generates a significantly lower counterforce than that in the pedal force simulator. Thus in this case, the spring in the pedal force simulator is barely compressed at all. One could also say that the pedal force simulator is not relevant here. The only remaining counterforce is the spring force of the spring in the shutoff unit, which is very low.