Electric Driveline Research Articles

Fuzzy-hybrid land vehicle driveline modelling based on a moving window subtractive clustering approach

In this article, the fuzzy-hybrid modelling (FHM) approach is used and compared to the input–output system Takagi–Sugeno (TS) modelling approach which correlates the drivetrain power flow equations with the vehicle dynamics. The output power relations were related to the drivetrain bounded efficiencies and also to the wheel slips. The model relates also to the wheel and ground interactions via suitable friction coefficient models relative to the wheel slip profiles. The wheel slip had a significant efficiency contribution to the overall driveline system efficiency. The peak friction slip and peak coefficient of friction values are known a priori during the analysis. Lastly, the rigid body dynamical power has been verified through both simulation and experimental results. The mathematical analysis has been supported throughout the paper via experimental data for a specific electric robotic vehicle. The identification of the localised and input–output TS models for the fuzzy hybrid and the experimental data were obtained utilising the subtractive clustering (SC) methodology. These results were also compared to a real-time TS SC approach operating on periodic time windows. This article concludes with the benefits of the real-time FHM method for the vehicle electric driveline due to the advantage of both the analytical TS sub-model and the physical system modelling for the remaining process which can be clearly utilised for control purposes.

Static and Fatigue Resistance of GRP Materials and Flywheel Disc of a Storage Unit for Environmentally Friendly Urban Vehicles

The paper presents results of a partial experimental programme carried out within the project EUREKA E! 2462 TRUS, which aim is to demonstrate a novel form of hybrid electric drive line without the need for overhead lines. The zero emissions public transport vehicle is based on a hybrid electric drive line with novel, strongly innovative features. The concept includes the use of a small on-board energy storage unit (flywheel) to store the energy that would otherwise be lost on braking. Results of an experimental complex programme of an evaluation of static mechanical and fatigue properties of long glass-fibre reinforced polyester composite material with biaxial or multiaxial structures, respectively, to be used for a manufacture of the flywheel hub disc are presented in the paper. It was shown that results of interlaminar shear fatigue strength of the disc mostly almost correspond to those obtained on basic material – biaxial GRP plates and are close to results obtained on a similar uniaxial GRP used for railways springs. Some ascertained differences are discussed.

Real life testing of a Hybrid PEM Fuel Cell Bus

Fuel cells produce low quantities of local emissions, if any, and are therefore one of the most promising alternatives to internal combustion engines as the main power source in future vehicles. It is likely that urban buses will be among the first commercial applications for fuel cells in vehicles. This is due to the fact that urban buses are highly visible for the public, they contribute significantly to air pollution in urban areas, they have small limitations in weight and volume and fuelling is handled via a centralised infrastructure. Results and experiences from real life measurements of energy flows in a Scania Hybrid PEM Fuel Cell Concept Bus are presented in this paper. The tests consist of measurements during several standard duty cycles. The efficiency of the fuel cell system and of the complete vehicle are presented and discussed. The net efficiency of the fuel cell system was approximately 40% and the fuel consumption of the concept bus is between 42 and 48% lower compared to a standard Scania bus. Energy recovery by regenerative braking saves up 28% energy. Bus subsystems such as the pneumatic system for door opening, suspension and brakes, the hydraulic power steering, the 24 V grid, the water pump and the cooling fans consume approximately 7% of the energy in the fuel input or 17% of the net power output from the fuel cell system. The bus was built by a number of companies in a project partly financed by the European Commission’s Joule programme. The comprehensive testing is partly financed by the Swedish programme “Den Gröna Bilen” (The Green Car). A 50 kW el fuel cell system is the power source and a high voltage battery pack works as an energy buffer and power booster. The fuel, compressed hydrogen, is stored in two high-pressure stainless steel vessels mounted on the roof of the bus. The bus has a series hybrid electric driveline with wheel hub motors with a maximum power of 100 kW. Hybrid Fuel Cell Buses have a big potential, but there are still many issues to consider prior to full-scale commercialisation of the technology. These are related to durability, lifetime, costs, vehicle and system optimisation and subsystem design. A very important factor is to implement an automotive design policy in the design and construction of all components, both in the propulsion system as well as in the subsystems.