Electric Vehicles in Hybrid Configuration

The utilization of fuel cells in propulsion systems for road transport applications raises the question of the optimal hybridization level between on board generation and storage of electric energy (batteries, supercapacitors). 

The main issues of hybrid propulsion systems are discussed in this chapter, drawing attention to basic characteristics of power train components and aspects of energy management within each hybrid configuration. The main characteristics of electric drives are described in Sect. 5.2, different types of electric energy storage systems are analyzed in Sect. 5.3 and Sect. 5.4, while different configurations of hybrid electric vehicles are discussed in Sect. 5.5, with particular reference to fuel cell propulsion systems (Sect. 5.5.4). 

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There is a large number of possible variations for the parallel hybrid configuration, besides that shown in Fig. 5.18, proposed by most of the major automobile companies. Some of them, for example, have a small electric machine in line with the crankshaft, where is usually located the flywheel in a IC engine vehicle. Another parallel hybrid configuration has the IC engine and the electric drive connected to different axles, as shown in Fig. 5.19, in particular in this case the IC engine drives the front wheels, the electric system the rear wheels and the road... 

The general theme of electric vehicles is covered in Chap. 5, with particular reference to hybrid vehicles that adopt both fuel cells and batteries/supercapacitors as power sources. The analysis of possible hybrid configurations is presented together with a review of different types of electric energy storage systems. 

Individual mobility is an indisputable asset of free and developed society. Road vehicles have played a vital role ever since they became affordable in the early twentieth century. Drivetrains based on combustion engines permit low costs and use fairly inexpensive fuel. For many reasons, the development of new propulsion technologies has become necessary and electric drivetrains - either single or hybrid configurations - are deemed promising concepts for future mobility. 

Fuel cell vehicle configurations Fuel cell vehicles can be classified as fuel cell electric and fuel cell hybrid vehicles [16,17], A fuel cell electric vehicle uses a fuel cell system as the power source without the use of the battery. A fuel cell hybrid vehicle consists of a battery or a supercapacitor [16] in addition to the fuel cell system. This configuration enables most efficient use of both the fuel cell and battery for vehicle propulsion. The battery (or supercapacitor) provides power during start-up and acceleration, and the fuel cell supplies the steady state load. 

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