Abstract
Keywords Brake actuation, continuous system simulation, booster, master cylinder, virtual prototyping.
Abstract Brake actuation unit is the first component after the pedal in the brake system of a car. In this system, a helping force coming from the vacuum of the car engine is added, in a controlled way, to the force applied in the pedal by the driver. As in the rest of the automotive industry, shortening the design cycle for this component is critical and, then, the use of advanced simulation tools becomes necessary.
The complexity of generating mathematical models to simulate the behaviour of this system is the coupling of multiple physical domains (mechanics, electrical/electronic/magnetic, pneumatics and hydraulics) in a single component and the influence in the booster performance of the deformation and friction on the rubber parts. The solution adopted to deal with this difficulties is the generation of dynamic models, using techniques of continuous system simulation, and combining them with results obtained from both computer fluid dynamics (CFD) on booster valve and finite elements analyses on elastomer components. With this methodology, accuracy in the results is highly improved with regard to using analytical approximations for air flow calculation and rubber parts characterisation, without the necessity of testing on real parts.
Validation of the virtual prototype is necessary to gain confidence in the results by the designers, so several test conditions are simulated and compared with experimental results.
The last step is the programming of a user-defined application for the interaction with the parameterised mathematical model and, in this way, providing an engineering tool for virtually testing and analysing the performance of the components, subassemblies and systems.