Development and experimental evaluation of the control system of a hybrid fuel cell vehicle

This work presents the development and experimental evaluation of a Fuel Cell Hybrid Vehicle, focusing on the control system. The main objective of this paper is to present a real vehicle which has been designed in order to demonstrate the feasibility of the use of hydrogen as an energy source for automotive applications. The paper describes the components that are integrated in the vehicle and presents several experimental results obtained during normal operation. A control system is designed and tested in order to perform all the operations related to the coordinated operation of the fuel cell, the intermediate electrical storage and the power train. Its main task is to compute the power that must be demanded to the fuel cell in real time. This computation is done in order to satisfy the power demand of the electric motor taking into account the state of charge of the batteries and the operating regime of the fuel cell. This is accomplished by manipulating the electronic converter which regulate the current that the fuel cell supplies to the batteries.Ministerio de Ciencia y Tecnología DPI2007-66718-C04-0

Urban and extra-urban hybrid vehicles: a technological review

Pollution derived from transportation systems is a worldwide, timelier issue than ever. The abatement actions of harmful substances in the air are on the agenda and they are necessary today to safeguard our welfare and that of the planet. Environmental pollution in large cities is approximately 20% due to the transportation system. In addition, private traffic contributes greatly to city pollution. Further, “vehicle operating life” is most often exceeded and vehicle emissions do not comply with European antipollution standards. It becomes mandatory to find a solution that respects the environment and, realize an appropriate transportation service to the customers. New technologies related to hybrid –electric engines are making great strides in reducing emissions, and the funds allocated by public authorities should be addressed. In addition, the use (implementation) of new technologies is also convenient from an economic point of view. In fact, by implementing the use of hybrid vehicles, fuel consumption can be reduced. The different hybrid configurations presented refer to such a series architecture, developed by the researchers and Research and Development groups. Regarding energy flows, different strategy logic or vehicle management units have been illustrated. Various configurations and vehicles were studied by simulating different driving cycles, both European approval and homologation and customer ones (typically municipal and university). The simulations have provided guidance on the optimal proposed configuration and information on the component to be used

Ultracapacitors in the Place of Batteries in Hybrid Vehicles

This paper is concerned with the use of ultracapacitors in hybrid vehicles in place of batteries. In the case of the mild, charge sustaining hybrid, the ultracapacitors would replace a lithium or nickel metal hydride battery: for a stop-start micro-hybrid, the capacitors would be used in combination with a lead-acid battery with the capacitors starting the engine, accepting energy during regenerative braking, and providing accessory loads during relatively short stop periods. Test data are shown for the performance of advanced carbon/carbon and hybrid lithium ultracapacitors indicating higher energy density (more than 2X) than that of commercially available carbon/carbon cells from Maxwell and NessCap. The advanced devices showed no sacrifice in high power capability in order to achieve the higher energy density. Simulations of mid-size passenger cars using the advanced ultracapacitors in micro-hybrid and charge sustaining hybrid powertrains were performed using the Advisor vehicle simulation program modified with special routines at UC Davis. The influence of the ultracap technology and the size (Wh) of the energy storage unit on the fuel economy improvement was of particular interest. Significant improvements in fuel usage were predicted for all the hybrid powertrains using ultracapacitors for energy storage. The results for the micro-hybrids indicated that a 7-25% improvement in fuel economy can be achieved using a small electric motor (4 kW) and small ultracapacitor units (5-10 kg of cells). The fuel economy improvements for the mild-HEV ranged from over 70% on the FUDS to 20% on the US06 driving cycle. In both microand mild-HEVs, the differences in the fuel economies projected using the advanced ultracapacitor technologies were very small. It is possible to store more energy using the advanced ultracapacitors, but the fuel savings appear be unaffected. The primary advantage of the advanced ultracapacitors is that the energy storage unit is smaller, lighter, and lower cost and there is more reserve energy storage to accommodate a wider range of vehicle operating conditions. In the mild hybrids, the fuel economy improvement was greater using ultracapacitors than with a lithium battery primarily because of the higher round-trip efficiency of the ultracapacitors

Ultracapacitors in Hybrid Vehicle Applications: Testing of New High Power Devices and Prospects for Increased Energy Density

The development of ultracapacitors (electrochemical capacitors) suitable for hybrid-electric vehicle applications has continued in various countries around the world even though automobile manufacturers have been slow to adopt the technology. Several of the new carbon/carbon and hybrid ultracapacitor devices being developed have been tested, as well as application of those devices in micro-hybrid and charge sustaining hybrid vehicles. Performance data for the ultracapacitors have been collected and analyzed. The influence of the ultracapacitor technology and the size of the energy storage unit (in Watt-hours) on the fuel economy improvement is also of particular interest

Sizing and Energy Management of a Hybrid Locomotive Based on Flywheel and Accumulators

The French National Railways Company (SNCF) is interested in the design of a hybrid locomotive based on various storage devices (accumulator, flywheel, and ultracapacitor) and fed by a diesel generator. This paper particularly deals with the integration of a flywheel device as a storage element with a reduced-power diesel generator and accumulators on the hybrid locomotive. First, a power flow model of energy-storage elements (flywheel and accumulator) is developed to achieve the design of the whole traction system. Then, two energy-management strategies based on a frequency approach are proposed. The first strategy led us to a bad exploitation of the flywheel, whereas the second strategy provides an optimal sizing of the storage device. Finally, a comparative study of the proposed structure with a flywheel and the existing structure of the locomotive (diesel generator, accumulators, and ultracapacitors) is presented

Topological analysis of powertrains for refusecollecting vehicles based on real routes – Part II: Hybrid electric powertrain

In this two-part paper, a topological analysis of powertrains for refuse-collecting vehicles (RCVs) based on simulation of different architectures (internal combustion engine, hybrid electric, and hybrid hydraulic) on real routes is proposed. In this second part, three different hybrid electric powertrain architectures are proposed and modeled. These architectures are based on the use of fuel cells, ultracapacitors, and batteries. A calculation engine, which is specifically designed to estimate energy consumption, respecting the original performance as the original internal combustion engine (ICE), is presented and used for simulations and component sizing. Finally, the overall performance of the different architectures (hybrid hydraulic, taken from the first paper part, and hybrid electric, estimated in this second part) and control strategies are summarized in a fuel and energy consumption table. Based on this table, an analysis of the different architecture performance results is carried out. From this analysis, a technological evolution of these vehicles in the medium- and long terms is proposed.Postprint (author's final draft

Parametric Study of Alternative EV1 Powertrains

The General Motors (GM) EV1 is an electric vehicle originally powered by either a PbA or NiMh battery pack. This paper examines the possibility of alternative powertrain configurations. These alternatives include an ultracapacitor (UC) storage system, fuel cell system with UC storage, and a fuel cell system with a NiMh battery pack. The configurations were simulated using ADVISOR. Parametric tests were performed by varying the size of the energy storage systems. The study of these combinations is followed by an examination of the current art of the hybrid energy storage topologies used to combine battery and ultracapacitor storage. These topologies include passive parallel, active parallel, cascade parallel, and multi-input bidirectional converter

A Hybrid Power Management (HPM) Based Vehicle Architecture

Society desires vehicles with reduced fuel consumption and reduced emissions. This presents a challenge and an opportunity for industry and the government. The NASA John H. Glenn Research Center (GRC) has developed a Hybrid Power Management (HPM) based vehicle architecture for space and terrestrial vehicles. GRC's Electrical and Electromagnetics Branch of the Avionics and Electrical Systems Division initiated the HPM Program for the GRC Technology Transfer and Partnership Office. HPM is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The basic vehicle architecture consists of a primary power source, and possibly other power sources, providing all power to a common energy storage system, which is used to power the drive motors and vehicle accessory systems, as well as provide power as an emergency power system. Each component is independent, permitting it to be optimized for its intended purpose. This flexible vehicle architecture can be applied to all vehicles to considerably improve system efficiency, reliability, safety, security, and performance. This unique vehicle architecture has the potential to alleviate global energy concerns, improve the environment, stimulate the economy, and enable new missions

Control and design considerations in electric-drive vehicles

Electric-drive vehicles have been identified as one of the promising technologies of the future. Electric-drive vehicles including fuel cell, hybrid electric, and plug-in hybrid electric vehicles have the potential to improve the fuel economy and reduce gas emissions when compared to conventional vehicles. One of the important challenges in the advancement of the electric-drive vehicles is to develop a control strategy which meets the power requirements of the vehicles. The control strategy is an algorithm designed to command the battery and the internal combustion engine of the vehicle for specific power demands. In this thesis, load follower and thermostat control algorithms have been analyzed and compared. A control strategy based on the combined urban and highway driving cycles has been proposed in order to obtain better fuel economy. In addition to this, proper choice of the energy storage system with respect to cost and capacity is another design challenge for electric-drive vehicles. In this thesis, an investigation has been done to identify the impact of different battery capacities and state of charge operating windows on the fuel economy of the vehicle. It is proven that the vehicle fuel economy is highly dependent on the battery state of charge whereas, battery sizing largely depends on the average daily driving distance and the driving conditions --Abstract, page iii

Energy Saving and Cost Projections for Advanced Hybrid, Battery Electric, and Fuel Cell Vehicles in 2015-2030

In this paper, the fuel savings, relative initial costs, and breakeven gasoline prices for mid-sized passenger cars utilizing advanced powertrains in 2015-2045 are compared to those using conventional and advanced engine/transmission power trains that would be available in the same time periods. The advanced powertrains considered are hybrid-electric (HEV and PHEV) and all-electric (EV) powered by batteries alone or by a hydrogen fuel cell. Large fuel savings compared to 2007 conventional passenger cars are projected by 2030 for all the advanced powertrains ranging from 45% with advanced engines in conventional vehicles to 60% in hybrid-electric vehicles (HEVs). The energy savings (combined gasoline and wall-plug electricity) for the PHEVs were 62% for the PHEV-20 and 75% for the PHEV-40. The energy saving for the FCHEV was 72% and for the BEV was 79%. The cost analyzes of the various advanced powertrains compared to the 2007 baseline vehicle indicated the most cost-effective was the HEV with a breakeven gasoline price of $2.50-3.00/gal gasoline for a five year payback period, 4$300- 700/kWh. The breakeven gasoline prices for the BEVs are higher than for the other advanced vehicles being $4-5/gal even for the$300/kWh batteries. The economic results for the FCHEVs indicate that target fuel cell costs of $30–50/kW, 10-year life, and hydrogen prices in the$2.50–$ 3.00/kgH2 range make fuel cell vehicles cost competitive with HEVs and ICE vehicles using advanced engines