The Energy Conversions in a Hybrid-Propulsion Vehicle with Planetary Gear Set

1 Chapter 1: Introduction and Background 1.1 Introduction The increasing concern about the polluting emissions of vehicles, the increasing cost and the limited availability of petroleum are urging many researchers in the world to develop innovative and more energy-efficient traction powertrains. In this work I explore, from a qualitative and quantitative point of view, the potentiality of a 4WD-layout hybrid powertrain that theoretically should be able to guarantee better fuel economy and improved energy conversion efficiencies in comparison with series and parallel hybrids. The most interesting characteristic of this powertrain is that it entails the advantages of both, the series and the parallel layouts, without many of their drawbacks. Chapter 2 contains a description of the powertrain, while chapter 4 shows the main simulation results. Some of the results obtained can however be adopted into electrical and other hybrid powertrains without any further change. I thus hope they will be useful to researchers are studying these kinds of vehicles too. 1.2 The needs and the efforts While in many of the world's largest cities in industrialising regions transportation is not yet the dominant cause of urban pollution, it is often the fastest growing segment. Furthermore, transportation currently accounts about one third of all greenhouse gas emissions from developed nations and consumes roughly 50% of the world's petroleum. In spite of the automobiles are becoming more ecological and efficient, the benefits are cancelled from the fast increase of the number of vehicles, especially on the Asian markets. In 1996 in the world circulated approximately 634 million vehicles, approximately 30% more than in 1986, that - according to the esteem of the International Energy Agency (IEA) - have emitted 3.7 billions of tons of carbon dioxide. Europe's road transport has increased dramatically over the last two decades. Between 1980 and 1997, the number of private cars in the EU rose from 100 million to 170 million, leading to a 62% increase in the volume of traffic (measured in passenger-kilometres). In 1998 alone there were 14 million new vehicle registrations - a 7% increase. The lorry and commercial vehicle fleet grew from 10 million to 19 million over the same period, with a 90% increase (in tonne-kilometres) in the goods transported, and road transport now accounts for 73% of the EU's freight volume. With the European transport as it stands at present, there are no signs of individuals or companies turning away from road transport, and traffic is continuing to increase at the rate of 2% a year. This is producing two major problems: traffic congestion (at a cost equal to 2% of Europe's GDP) and increasing pressure on the environment; despite lower fuel consumption and cleaner fuels, road transport accounts for almost 25% and 50% of manmade CO 2 and NO x emissions respectively [RTD info 25, 2000]. Over the past years, Paris, Moscow and Mexico City, among others, have instituted several-day car bans because of serious smog episodes. Italy is proposing car sharing programs and requiring "green" car purchases for government fleets. Recently six large European cities started a trend toward giving preferential access based on emissions: zero or low emission vehicles would be the only kind allowed into the restricted zones in Athens,