Fabio Mazzariol Santiciolli

Gear Shifting Strategies Co-simulations to Optimize Vehicle Performance and Fuel Consumption

The vehicle longitudinal dynamics is responsible for calculating the vehicle power consumption to attend a specific route, estimating, by the equations, the forces acting on the system such as aerodynamic drag, rolling resistance, climbing resistance and the driver behavior. The gear shifting strategies influence significantly in the vehicle acceleration performance and fuel consumption because it changes the powertrain inertia and the engine speed. The literature presents gear shifting strategies based on the engine power and torque. A fuel economy strategy is more difficult to determine, because it depends on a large number of factors like the engine efficiency, vehicle speed, transition ratio and required acceleration. This paper presents a study based on the US06 standard velocity profile, in which the high speeds and acceleration stretches create a situation where the vehicle performance is limited by the engine available power and by the tire-ground traction limit. Because of the many factors involved in the vehicle behavior, it was developed an algorithm to optimize the gear shifting process to choose the more adequate strategy to each stretch. The analysis were performed by co-simulation between the multibody dynamics software Adams\( ^{\rm{TM}} \) and Matlab/Simulink\( ^{\rm{TM}} \), where is defined the vehicle power demand.

Vehicle gear shifting strategy optimization with respect to performance and fuel consumption

ABSTRACT Based on the movement resistance forces, the vehicle longitudinal dynamics is related to power demand for a specific route. The vehicle gear shifting influences significantly the acceleration performance and fuel consumption because it changes the engine operation point and the powertrain inertia. This paper presents a study based on the US06 velocity profile that involves high speed and high acceleration phases, where the vehicle performance is limited by both the engine power and the tire traction limit. For improving the vehicle performance without increasing fuel consumption, a genetic algorithm (GA) technique is used.

A study of battery power for a different electric vehicle propulsion system

This paper presents a simulation of an electric vehicle propulsion system. The simulation assumes BLDC motors combined with a proportional-integral controller and batteries. Regarding the longitudinal dynamics of electric vehicles (EV), models of different components and configurations are introduced and simulated. The simulations show the potential of each configuration according to the battery size. Thus, the objective is to find the best configuration (batteries size and propulsion system setup), keeping the original drivability. Six different configurations will be analyzed using the standard Brazilian urban driving cycle NBR6601. A rule-based method is used in the power management strategy that indicates the batteries states. This information aids the decision on the correct specification of the battery for each simulated configuration according to some restrictions.

Simulation of the scenario of the biaxial wheel fatigue test

Abstract This paper presents a new approach to the virtualization of the scenario of the biaxial wheel fatigue test. This test is the state-of-art and the standard requirement for the validation of vehicle wheels. During this test, tire and wheel specimens run inside an inner drum while standardized vertical and horizontal loads are applied. Thus, the scenario of this test can be modeled in three levels: the multibody dynamics of the test facility, the wheel/tire/inner drum contact, and the analysis of the flexible wheel. In the proposed virtualization, the multibody dynamics of the test facility was implemented in MSC.ADAMS. The wheel/tire/inner drum contact was simulated by means of CDTire; as it works parallel to MSC.ADAMS, one single co-simulation could perform the tire dynamics and the test facility dynamics. Finally, the wheel strains were calculated by an ABAQUS simulation, which received the tire/wheel load data from the simulation in MSC.ADAMS and CDTire. A physical test facility and a physical wheel specimen were instrumented, allowing the comparison between acquired and simulated data. The use of this specialized software is a novelty in the virtualization of the scenario of this test; furthermore a high detailed simulation is required for the further development of such already well established test procedure.

Gear shifting multi-objective optimization to improve vehicle performance, fuel consumption, and engine emissions

ABSTRACT In the present work, the Adaptive-Weight Genetic Algorithm was employed in order to determine the gear shifting strategies that allow an automobile to work in the best compromise among fuel consumption, engine emissions, and vehicle performance. For the assessment of each of the three objective functions, a simulation model based on engine data and on the well-established equations of the longitudinal dynamics was developed. The driving cycle chosen for the calculations was the FTP-75, which takes into account both cold and hot starts, meaning that the transient operation during the warm-up of the catalyst is also considered.

Study of Different Electric Vehicle Propulsion System Configurations

This paper presents a study of an electric vehicle (EV) with two different drive systems and three available electric motors (EMs) configurations. The EMs are BLDC (Brushless Direct Current) motors combined with a proportional-integral controller (PI). The vehicle power demand is divided between the drive systems through rules based vehicle power management control (PMC) that aims to reduce the lithium-ion battery discharges during the Brazilian urban driving cycle NBR6601. The results indicate the potential of each simulated configuration and the combination drive system/EM in which present the lower battery discharge. Each EV configuration is compared and the best configuration is defined.

Gear Shifting Strategy to Improve the Parallel Hybrid Vehicle Fuel Consumption

The hybrid electric vehicle (HEV) is an alternative to reduce the engine fuel consumption due to the extra electrical power addition in the system that allows changing the engine operation point for a better efficiency region. The gear shifting strategy is a way to modify the engine operation point and it can be combined with the power management strategy to reach a better operational condition. The aim of this study was to analyze the influence of the gear shifting strategy in the HEV configuration, comparing a conventional 1.0L vehicle with a parallel HEV.

A lateral dynamics of a wheelchair: identification and analysis of tire parameters

In vehicle dynamics studies, the tire behaviour plays an important role in planar motion of the vehicle. Therefore, a correct representation of tire is a necessity. This paper describes a mathematical model for wheelchair tire based on the Magic Formula model. This model is widely used to represent forces and moments between the tire and the ground; however some experimental parameters must be determined. The purpose of this work is to identify the tire parameters for the wheelchair tire model, implementing them in a dynamic model of the wheelchair. For this, we developed an experimental test rig to measure the tires parameters for the lateral dynamics of a wheelchair. This dynamic model was made using a multi-body software and the wheelchair behaviour was analysed and discussed according to the tire parameters. The result of this work is one step further towards the understanding of wheelchair dynamics.

Application of Pattern Recognition for the Mitigation of Systematic Errors in an Optical Incremental Encoder

The accuracy and reliability in the measurement of the instantaneous angular speed (IAS) by incremental encoders are fundamental for speed and torque control systems. An error in the acquisition of this variable may cause instabilities or even render the system unfeasible. Many works deal with this problem, which in some cases is caused by the imperfections in the disk manufacturing or also shaft misalignments. Due to the systematic character of these type of error, in this work an error pattern in the encoder signal of a vehicle dynamometer was identified by means of a calibration process and detected along the experiment by minimizing the total variation of the corrected angular speed curve. By making use of this procedure, not only the measurement became more accurate, but also the direction of rotation and angular position of the rotary system could be detected with only one channel of the encoder sensor being acquired. After the application of this method, the measurement error was reduced by 84.22%, even in transient conditions, without the application of further filtering methods, which may unwantedly lead to phase shifting in the IAS signal.

Multibody Model of a Small Tire Test Bench

In despite of the necessity to control the mobile robots, it is possible to observe the absence of tire models and experimental parameterization regarding small tires. This paper aims to collaborate with part of the fulfilment of this gap in the literature by proposing some updates to a test bench that focus on the parameterization of small tires. The multibody dynamics model including the updates of the test bench was executed in ADAMS/View in order to indicate whether these updates are feasible and whether the data acquired by the virtual load cells is correlated with the virtual tire contact loads. The resulting virtual tire contact loads are compared with the ones calculated directly by ADAMS/Tire routine and by Pacejka equations, demonstrating a good correlation.