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Engines and fuels of the future in the automotive industry

©2007 Hausarbeit 37 Seiten


This essay is about the engines and fuels of the future in the automotive industry. It tries to find out whether these technologies are suitable for the purpose to reduce pollutant emissions. Furthermore, it will consider the potential of the engines/fuels which they can contribute to an sustainable energy supply in the traffic sector, independent of the use of crude oil.



1. Problem definition and goals of this study

2. Engines and fuels of the future in the automotive industry
2.1. Engines of the future in the automotive industry
2.1.1. Fuel cell as an engine of the future
2.1.2. Hybrid-electric power drive as an engine of the future
2.2. Fuels of the future in the automotive industry
2.2.1. Hydrogen as a fuel of the future
2.2.2. Bio-ethyl-alcohol as a fuel of the future
2.2.3. Liquified petroleum gas as a fuel of the future

3. Conclusion and prospect to the future

4. Bibliography

1. Problem definition and goals of this study

Nowadays, globalisation requires flexibility and mobility from the participants of free market economy as never before. The general passenger- and goods-traffic have to prove this demand. As a result, volume of traffic on streets has become more and more continuously. In Germany alone, the number of the registered automobiles has risen to almost 46.1 million in 2006 ( But the growth rate is considerably higher in countries with high population like China or India. Due to the involvement into international economics, its inhabitants are more and more in a position to afford mobility in form of own cars (Brenner, Because of this fact, it is assumed that the Chinese automotive market will be the biggest one of the world in 2020 (Naunin, in 2007, p. 65). A research of the United Nations even resulted that the number of automotives will rise from almost 800 million in the year 2000 to about 1.6 billion in the year 2030 (Naunin, in 2007, p. 118).

Present combustion engines of these vehicles mostly need – to cover its energy-demand – crude oil based fuels. To be able to imagine the dimension of this energy requirement let me cite a figure: In 2004, traffic in Germany required 59 million tons of crude oil based fuels.[1] The share of it for the German road traffic was with 85 percent very noticeable (BMU Erneuerbare Energien, in 2006, p. 104).

At the combustion of such fossil fuels, harmful substances for environment and health arise from carbon monoxide, carbon dioxide, nitrogen oxide, hydrocarbon and sooty particle (BMU Aus Verantwortung für die Zukunft, in 2007, p. 38).

Assuming that, as aforementioned, the number of automotives will rise dramatically in future, one can imagine to what extent traffic contributes to environmental pollution and its consequences nowadays and in which way it will do in the future. The following figure shows clearly the described positive correlation between the increase of primary energy, population and the carbon dioxide emissions.

Illustration 1: Development of the global carbon dioxide emissions

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Development of the global energy-related carbon dioxide emissions since 1870 and its

chief causes: population growth and combustion of coal, mineral oil and natural gas.


Carbon dioxide is being hold responsible for the greenhouse effect und consequently, for global warming. Thus, the goal must be to diminish these emissions. A representative survey found out, that this topic is attached importance to the German population. So, 45 percent of the Germans want make the Federal Government to see, that polluting emissions will be reduced in a considerable way in the future. Furthermore, actually 59 percent of the Germans claim measures for a substitution of the fossil energy supply with renewable energies, like sun-, wind- and waterpower (BMU Umweltbewusstsein in Deutschland, in 2006, p. 24).

It is not only reasonable to create an independence of crude oil owing to environmental causes but also due to the fact that the global oil-resources are finite. Especially the traffic is dependent on fossil deposits exceedingly, because most of the vehicles nowadays are powered by petrol engines and diesel engines (Naunin, in 2007, p. 66). Benzine and diesel, which is being used for this purpose, work in an efficient way and in comparison with this fact, these fuels are low-cost fuels. However, in the last years prices for crude oil escalated due to the shrinking supply of oil. Because of this fact and facing the environmental difficulty, more and more thoughts about the use of other competitive engines and fuels come to the fore (Krüger, in 1997, p. 13).

In this essay, I want to address myself to this question – the engines and fuels of the future in the automotive industry. I want to find out whether these technologies are suitable for the purpose to reduce pollutant emissions. Furthermore, I will consider the potential of the engines/fuels which they can contribute to an sustainable energy supply in the traffic sector, independent of the use of crude oil.

Here at the point of realisation, the automotive industry has a mighty position of influence. Because this industry is actively involved in the development of the supply of vehicles with clean technologies. The following illustration from the association of the German automotive industry (VDA) shows that the automotive industry can show first results on its way to a reduction of carbon dioxide emissions. The continuous decline of these gas emissions is recognisable since the year 2000. That could be achieved through improvements and effectiveness increases of combustion engines (decrease of fuel consumption). For the future, a further decline is forecasted.

Illustration 2: Carbon dioxide emissions of the road traffic – the peak is over

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According to the VDA, Carbon dioxide emissions should decline

of 20,000 kilotons once more up to the year 2030.


This further reduction will be considerably traced back to the fact of launching new engine systems and fuels. That includes technologies as the hybrid-electric power or hydrogen. Illustration 3 shows further existing opportunities with promising chances. The main conclusion of this picture is, that the automotive favours the hydrogen-alternative in the long run, whereas other variants are only seen as interim solutions. Also the Federal Environment Ministry aspires the long-term objective hydrogen as a fuel or for the use in fuel cells (illustration 4).

Illustration 3: The roadmap of the engine and fuel technology

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On the left hand side, there are the fuels listed, on the right hand concepts of engines.


Illustration 4: Strategic overall concept of the fuel-strategy

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However, in my essay I want to discuss only the following selected and promising engines and fuels of the future. These are the fuel cell, the hybrid-electric power, hydrogen, bio-ethyl-alcohol and liquefied petroleum gas (LPG). I would like to discuss the last named topic more intensive, because I reequipped my car for LPG-handling last autumn and thus, I want to insert my experiences with this fuel-alternative into my essay. Furthermore I want to point out that my researches and conclusions of this essay are only based on private cars (neither commercial vehicles nor public transports).

Before I started the elaboration to my topic, I have decided to present at first the both engine alternatives (fuel cells and hybrid-electric power) in a general way, including the advantages and disadvantages of these variants. In addition I will light up its sustainability critically. On the other hand, the procedure of the fuel presentation is structured in a different way. I will introduce each kind of fuel with a short overview about its origin. Then, I will describe how the respective fuel is manufactured and where it could be produced economically. Central decision criteria about the sustainability of the fuel alternatives (for example emissions and profitability analysis) as soon as the advantages and disadvantages will be mentioned later on, before I would like to complete the chapter by a critical conclusion.

As a result of my analysis of engines and fuels of the future in the automotive industry, I have come to the conclusion, that in my opinion – concerning the environmental factors and resource aspects – no engine and no fuel will stand alone for the future technology. Rather I am persuaded of the fact, that the hybrid technology, connected with the recovery of brake energy and the feed of the rolling energy from down-drives from mountains, together with an optimum bio-fuel and an optimised vehicle form, would be the best choice economically and ecologically. I think, that would capture the global market.

2. Engines and fuels of the future in the automotive industry

Before picturing the engines and fuels of the future, it must be checked – for a better understanding – in which case engines and fuels differ from each other.

An engine converts the energy which comes from external energy storages, into mechanical movements. It is the technology for the operation of an engine. Here as an example one can call the typical internal combustion engine, but also the hybrid technology falls under this concept.

However, a fuel is the energy source which feeds the engine. Examples for this are petrol, liquid gas, natural gas or also hydrogen.

2.1 Engines of the future in the automotive industry

2.1.1 Fuel cell as an engine of the future

Fuel cell vehicles are driven with electric energy which is generated of hydrogen and oxygen in the fuel cell. Therefore, fuel cells deliver electric energy, as well as batteries. But the fuel cell has a determining advantage in contrast to a battery. While batteries, which store chemical energy and deliver when required, must be charged over and over again, the fuel cells convert chemical energy of the hydrogen into electric energy, as long as being supplied with fuel (Rifkin, in 2002, p. 204). Thereby, the hydrogen is indispensable as a final energy source and cannot be substituted with other fuels. Indeed, it is possible to convert methanol or natural gas in the vehicle into hydrogen, however, this procedure is very costly and not recommendable with look at the energy balance (Krüger, in 1997, p. 87). Further information

on the subject hydrogen in detail is performed in the subject area “fuels of the future”.

Fuel cells deliver electric energy to the electric motor, which then drives the vehicle. This procedure occurs without a forming of greenhouse gas emissions, because as a waste product, solely a mixture of water and rest air discharges (Naunin, in 2007, p. 131). Due to the fact that the production of hydrogen is very energy-intensive, this kind of engine does only make sense if the hydrogen is produced with the help of renewable energies.

The fuel cell essentially – like illustration 5 points – is composed of three components: The fuel-electrode (anode), the oxygen-electrode (cathode) and the electrolyte. The task of the electrolyte is to undertake the ion transport at the electro-chemical reaction. By adding hydrogen to the anode, the electrons are took away from the hydrogen by electro-chemical oxidation. The protons (hydrogen ions) pass towards the cathode through the electrolyte (polymer membrane) which separates the fuel-electrode from the oxygen-electrode of each other. At the oxygen-electrode, the hydrogen ions combine with the aerial oxygen to water (Naunin, in 2007, p. 132/133).

The electrons which were isolated from the hydrogen in the beginning, generate electric energy. This happens beyond the electrolyte on their way to the cathode (they cannot penetrate the electrolyte). This process occurs in only one step, without thermal or mechanical intermediate stages (Krüger, in 1997, p. 85).

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Illustration 5: The mode of operation of a fuel cell

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If several fuel cells are summarised, one can speak from a fuel-stack. The electric energy, generated here, is sufficient to drive an electric motor.

In vehicles with fuel cell engine, as described on top, the chemical energy and not the electric energy must be refuelled in form of hydrogen. The storage possibilities of hydrogen as a fuel is suboptimal in spite of technical progress yet and that fact makes difficulties for the car industry. Today, three types of storages are known: the storage of hydrogen in liquid form, compressed in gas form or stored in metal hydride. While the last-called kind of storage probably will not assert on the market because of resources-technical and economical reasons, both other possibilities are more promising. Now, I would like to introduce these methods in the essentials.

Storage of hydrogen in liquid form

By bringing hydrogen on a temperature of –235° C, it switches from the gaseous state into the liquid aggregate state. Thereby, the density of the fuel increases considerably what entails that more energy can be stored in a tank with a limited volume. However, to avoid a boost of the hydrogen temperature, what would lead to a vaporisation of the fuel and therefore to a volume expansion, the tank must be isolated very well. But a rise of the temperature cannot be avoided in the long run. Thus, it is tried to keep the hydrogen cool as long as possible (Naunin, in 2007, p. 137).

If it comes to a vaporisation of the liquid hydrogen, a raised pressure would not lead to consequences, provided that the owner of the fuel cells vehicle drives a lot with his/her car. Because by the use of the car, the excessive pressure could be used without losses for the power production, completely. It comes to so-called “Boil-Off-Losses”, if a not allowed working pressure is based by the evaporating hydrogen in the tank. Then, a part of the hydrogen gas must be let off controlled (Naunin, in 2007, p. 137).

Storage of hydrogen compressed in gas form

A rise of the energy density of the hydrogen gas is also possible by compressing the gas. To be able to achieve a satisfactory range with fuel-cells- or hydrogen-vehicles, a very high pressure of hydrogen is required. At a maximum storage pressure of 700 bar, a further rise in pressure results no substantially higher storage amount and, besides, the constructive expenditure of the storage tank increases disproportionate (Naunin, in 2007, p. 138).

The high-pressure tank system exists of a seamless, hydrogen-impervious internal cover, a high-strength sheath from coal fibre material, which stands firm to such a high pressure certainly, as well as a patented protective winding. This system has been certificated completely by German guidelines for pressure tanks through the safety standards authority (Naunin, in 2007, p. 138).

Advantages and disadvantages of the fuel cells technology

The most essential advantage of a vehicle with fuel cell engine is, that at the operation no harmful substances originate and therefore, the environment is not being polluted (Krüger, in 1997, p. 65). However, that does not mean, that no energy is required for the supply of the fuel (hydrogen) as well as the production of the engine (fuel cells). On the contrary: The production of hydrogen is very energy-intensive, as mentioned above. Also the production of fuel cells even today is connected with a high energy- and resources-application and thus, very expensive. On account of the high cost situation, it is tried to reduce the necessary amount of platinum in the fuel cell. Nevertheless, one has not succeeded up to now in lifting the costs and energy consumptions on a capable level of market (Naunin, in 2007, p. 120).

By comparing additionally the efficiency of a fuel cell engine to that of a combustion engine in hydrogen vehicles, the result argues definitely for the fuel cell, because in combination with the electric motor, it is more efficient than the combustion engine. Therefore, less amounts of the energy source hydrogen are needed (Krüger, in 1997, p. 88). In addition, still a pleasant aspect lets make a note as an advantage, namely that that the operation of a fuel cell causes no noises (Krüger, in 1997, p. 85).


[1] Traffic is the second largest consumer of energy in Germany’s economy. It is only outbalanced by public
households (BMU, Erneuerbare Energien, 2006, p. 104).


ISBN (eBook)
ISBN (Paperback)
1.2 MB
Institution / Hochschule
Hochschule für Technik, Wirtschaft und Gestaltung Konstanz
2008 (Juni)
Engines Environment Economics

Titel: Engines and fuels of the future in the automotive industry