Electric Vehicles

Traction alternatives viewed from the perspective of drive axis choice remain an important topic in vehicle design. Electric and hybrid vehicle design alternatives have been proposed where each axis powered by a different engine (electric and internal combustion). This draws attention to the problem of gradeability in alternative drive axis configuration when towing in a steep grade, to avoid slipping. The paper demonstrates the use of analytical methods to analyse the fundamental mechanical relationships that govern the gradeability of a two axis vehicle towing a single axis trailer, consider three drive axis alternatives (Front Wheel Drive - FWD), Rear Wheel Drive-RWD and All/Four Wheel Drive-AWD/4WD). The differences between FWD and RWD are small, supporting the 4WD option as the most robust alternative, calling for 4WD selection mode in Electric Vehicles.

"In this chapter, the historical development in the use of electric cars is
described within a global content as occuring in five evolutions or waves, since
1835. The last two waves are described in more detail through the following case
studies, the French VEL car and the Norwegian THINK car. They each had their
own series of setbacks including. Problems in electro-chemistry, which have
caused important limitations, as they have through the whole history of electrical
cars. Unintended consequences in the form of increased human toxicity, fresh-
water eco-toxicity, freshwater eutrophication, and metal depletion, from potential
increases in the future number of electric vehicles, are explained. Finally, a critical
view on the policies for promoting the use of electric cars is presented."

Cette communication traite des conditions d'application de la théorie des lignes de transmission classique. Elle présente une évaluation des erreurs commises lors de l'utilisation de cette théorie dans certaines conditions particulières. L'objectif est de cerner les situations pour lesquelles une solution alternative à la théorie des lignes de transmission classique (TLT)  doit être recherchée.

In this paper, a modified enhanced transmission-line theory taking into account higher-order modes is described. The new equations are based on the correction of the per-unit-length parameters that become frequency dependent and contain the radiation resistance. In particular, the per-unit-length resistance takes into account this radiation resistance and an additional resistance proportional to the imaginary part of the characteristic impedance. This additional resistance is identified as responsible of the current attenuation on the line. These new parameters are described in a per-unit-length RLCG form and can then easily be introduced in a classical transmission-line equation solver. Satisfactory results are obtained when comparing this new model to a full-wave model.

The paper shows actual directions in marketing and management of eco-innovations that are due to several important barriers less market-driven than other innovations. First, we review main definitions and identify driving forces on the market of eco-innovations based on the empirical evidence collected in last decade. The rest of the paper is devoted to sustainable business models as a way to overcome the barriers of eco-innovations and offers a single-case study in order to get a deeper view into the success of Tesla Motors Inc. business model.

In this investigation a test bench for the simulation of hybrid power trains combining fuel cell and batteries is proposed. The developed test bench offers a high flexibility as different fuel cells, batteries and loads can be tested in the power train in an effective and affordable way. The fuel cell is simulated with a dynamic electric model and a power source, which enables the simulation of fuel cells in a wide range of power and types. Batteries can be connected to the power source which simulates the fuel cells in different configurations (series, parallel, etc.). The hybrid power train formed by the direct current power source and the batteries are able to supply the power requested by a DC electronic load. The dynamic fuel cell model was validated, an experimental setup was assembled and successful tests were carried out.

"Electric vehicle (EV) due to its running zero
emission, sustainability and efficiency is of interest for future
transportation. In-wheel technology has been one of the main
research concentration points in last decade. BLDC motor is on
demand for in-wheel application because of its high efficiency,
torque/speed characteristics, high power to size ratio, high
operating life and noiseless operation. In this paper direct
torque control (DTC) switching technique of BLDC motor for
EV propulsion system is proposed and simulated in MATLAB/
SIMULINK. The Simulation results show effective control of
torque and remarkable reduction of torque ripple amplitude as
compared to conventional reported switching techniques.
Improvements of in-wheel motor’s torque controllability result
to have more efficient and safer electric vehicle. The simulation
results of proposed switching system are satisfactory and show
correct performance of system."