The dynamic performance and economic benefit of a blended braking system in a multi-speed battery electric vehicle

Abstract

As motor-supplied braking torque is applied to the wheels in an entirely different way to hydraulic friction braking systems and it is usually only connected to one axle complicated effects such as wheel slip and locking, vehicle body bounce and braking distance variation will inevitability impact on the performance and safety of braking. The potential for braking energy recovery in typical driving cycles is presented to show its benefit in this study. A general predictive model is designed to analysis the economic and dynamic performance of blended braking systems, satisfying the relevant regulations/laws and critical limitations. Braking strategies for different purposes are proposed to achieve a balance between braking performance, driving comfort and energy recovery rate. Special measures are taken to avoid any effects of motor failure. All strategies are analyzed in detail for various braking events. Advanced driver assistance systems (ADAS), such as ABS and EBD, are properly integrated to work with the regenerative braking system (RBS) harmoniously. Different switching plans during braking are discussed. The braking energy recovery rates and brake force distribution details for different driving cycles are simulated. Results for two of the cycles in an 'Eco' mode are measured on a drive train test rig and found to agree with the simulated results to within approximately 10%. Reliable conclusions can thus be gained on the economic benefit and dynamic braking performance. The strategies proposed in this paper are shown to not only achieve comfortable and safe braking during all driving conditions, but also to significantly reduce cost in both the short and long term.

Análisis termodinámico de un disco de freno automotriz con pilares de ventilación tipo NACA 66-209

“…Actualmente, investigadores de la University of Technology Sydney simularon, en un banco de pruebas, el comportamiento del disco de freno para obtener el beneficio económico y dinámico en el rendimiento del sistema, con lo que se comprobó la eficiencia del sistema en diferentes condiciones de operación [14] [15]. Asimismo, se obtuvieron perfiles de frenado mediante el modelado y análisis numéricos de los componentes del sistema con la finalidad de predecir su comportamiento en diferentes usos a los que puede ser sometido, teniendo en cuenta los resultados del análisis de elementos finitos (FEA) para validar los resultados [16].…”

Dynamic analysis of three autoventilated disc brakes

“…Researchers at the University of Technology in Sydney simulated the behavior of the brake disc in a test bed to obtain the economic and dynamic benefit of system performance. With this, the efficiency of the system was verified in different operating conditions (Ruan, Walker, Watterson, & Zhang, 2016). Also, braking profiles were obtained by modeling and numerical analysis of the components of the system in order to predict their behavior in different uses to which it can be submitted; Taking into account the results of finite element analysis (FEA) for validity the results (Gulec, Yolacan, & Aydin, 2016).…”

Enhanced Regenerative Braking Strategies for Electric Vehicles: Dynamic Performance and Potential Analysis

“…For electric vehicles with an RBS, the available regenerative braking torque is limited by the motor peak torque [20]. When a braking situation occurs, mechanical braking always supplies the braking torque on the front and rear wheels, whereas the motor is selectively incorporated, based on various strategies and braking situations.…”

“…To fully utilize the braking energy, the ecology (ECO) strategy is proposed [20]. This strategy is designed for city cycle situations; only electric motor braking is applied until the motor reaches its maximum capacity.…”

“…An emergency braking strategy is also presented for the situation of severe braking [10,20]. Once wheel slippage occurs, or the value of brake strength (z) exceeds 0.7, the serial strategy automatically switches to the emergency strategy, in which the distribution of the braking force on the front and rear wheels strictly follows the ideal braking force distribution curve, to maximize brake performance.…”