Comparison of a State of the Art Hydraulic Brake System with a Decentralized Hydraulic Brake System Concept for Electric Vehicles

The ongoing changes in the development of new power trains and the requirements due to driver assistance systems and autonomous driving could be the enabler for completely new brake system configurations. The shift in the brake load collective has to be included in the systems requirements for electric vehicles. Many alternative concepts for hydraulic brake systems, even for decentralized configurations, can be found in the literature. For a decentralized system with all state of the art safety functionalities included, four actuators are necessary. Therefore, the single brake module should be as cost-effective as possible. Previous papers introduced systems which are for example based on plunger-like concepts, which are very expensive and heavy due to the needed gearing and design. In this paper a comparison between a state of the art hydraulic brake system using an electromechanical brake booster, and a completely new decentralized hydraulic brake concept is presented. After introducing the two systems, the paper focuses on the question, what advantages can be achieved by a hydraulic actuation close to the wheel in comparison to a centralized system. Therefore, key figures, which have been introduced in previous work, will be used and extended to evaluate the systems and compare their performance. They are related to dynamics and efficiency, like time to lock (TTL), hydraulic efficiency and energy consumption. This overall rating approach can be a guideline for developers choosing and developing the ideal brake system concept for a target vehicle.