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Brake systems represent important components for passenger cars since they are strictly related to vehicle safety: Anti-lock Braking Systems (ABS) and Electronic Stability Control (ESC) are the most well-known examples. The paper is focused on the characterization of the braking hydraulic plant and on the design of a pressure following control strategy. This strategy is aimed at pursuing performances and/or comfort objectives beyond the typical safety task. The low-level logic (focus of the paper) consists of a Feedforward and Proportional Integral controller. A Hardware In the Loop (HIL) braking test bench is adopted for pressure controller validation by providing some realistic reference pressure histories evaluated by a high-level controller. Results prove that innovative control strategies can be applied to conventional braking systems for achieving targets not limited to braking issues, i.e., comfort or NVH tasks.

During some critical maneuvers, transmission systems using Dual Mass Flywheel (DMF) may experience overtorques, which could lead to structural damages of the transmission components. In a dual mass flywheel, total inertia is divided into two parts: a primary mass connected to the engine and a secondary mass to the transmission. The torque delivered by the engine is transferred from one mass to the other through a drive plate and a set of arc springs, the latter absorbing the torsional oscillations coming from internal combustion engine and the shocks caused by fast clutch engagements. This paper investigates overtorque issues and proposes a solution based on a torque limiter, consisting of a friction clutch inserted between the two masses, that limits the maximum torque transmitted through it. The basic idea is to replace the classic flat drive plate with a tapered drive plate that functions as a Belleville spring.

This paper explores the potentiality of reducing noise and vibration of a vehicle transmission thanks to powertrain control integration with active braking. Due to external disturbances, coming from the driver, e.g. during tip-in / tip-out maneuvers, or from the road, e.g. crossing a speed bump or driving on a rough road, the torsional backlashes between transmission rotating components (gears, synchronizers, splines, CV joints), may lead to NVH issues known as clonk. This study initially focuses on the positive effect on transmission NVH performance of a concurrent application of a braking torque at the driving wheels and of an engine torque increase during these maneuvers; then a powertrain/brake integrated control strategy is proposed. The braking system is activated in advance with respect to the perturbation and it is deactivated immediately after to minimize losses.

The paper deals with the methodology implemented by Magneti Marelli and Politecnico di Torino Vehicle Dynamics Research group to develop and verify the software of active chassis and powertrain control systems through a Hardware-In-the-Loop automated procedure. It is a general procedure which can be adopted for all the active chassis control systems, not only for their development but also for the verification of their reliability. The steps of the procedure are described in the first part of the paper. The specific application on which this paper is focused concerns robotized gearboxes.

The nonlinear behavior of automotive powertrains is mainly due to the presence of backlash between engaging components. In particular, during tip-in or tip-out maneuvers, backlash allows the generation of impacts that negatively affect the vehicle NVH performance. Due to the faster response of electric motors with respect to conventional internal combustion engines, this problem is even more critical for electric vehicles. In order to employ numerical optimal control methods for backlash compensation, the system states have to be known. In this paper, an electric powertrain is modeled as a two-mass oscillator with lumped backlash. This model estimates the system states when in no-contact mode while a Kalman filter that relies only on commonly available speed measurements is active in the contact phase. The powertrain model is validated using experimental data collected during vehicle testing and the online estimated half-shaft torque is shown.

This paper investigates the torsional dynamic behaviour of a Dual Mass Flywheel (DMF) both numerically and experimentally. First, the experimental setup is described, followed by a mathematical description in the frequency domain of the mechanical system under test, using a lumped parameter model. An analytical expression for the frequency response function describing the rotational dynamics is derived and compared with experimental data. Sine sweep tests are used to characterise the system, imposing constant amplitude excitation, i.e. the torque applied to the engine side of the DMF. Moreover a method for enhancing the dynamic performance of the electric motor torque control is suggested in order to use it as a torsional shaker.

Over the next decade, CO2 legislation will be more demanding and the automotive industry has seen in vehicle electrification a possible solution. This has led to an increasing need for advanced powertrain systems and systematic model-based control approaches, along with additional complexity. This represents a serious challenge for all the OEMs. This paper describes a novel reverse engineering methodology developed to estimate relevant powertrain data required for fuel consumption-oriented hybrid electric vehicle (HEV) modelling. The estimated quantities include high-voltage battery internal resistance, electric motor and transmission efficiency, gearshift thresholds, torque converter performance diagrams, engine fuel consumption map and front/rear hydraulic brake torque distribution. This activity provides a list of dedicated experimental tests, to be carried out on road or on a chassis dynamometer, aiming at powertrain characterization thanks to a suitable post-processing algorithm.