Preface

Fuels for internal combustion engines must meet certain requirements, directly related to the processes of evaporation and combustion of fuel and indirectly to ensure an adequate performance, fuel consumption and environmental protection, as well as ensuring the ra‐ tional exploitation in general.

Development and modifications of modern engines drives therefore require the appropriate fuels to these drives, so that the above requirements have been met. Those limits are speci‐ fied by designers and manufacturers of vehicles, while ensuring the durability and reliabili‐ ty of engines fuelled with appropriate fuel.

Researches on processes for obtaining substitutes of previously used fuels, defined as "alter‐ native fuel" for motor petrol, diesel fuels, and even aviation fuels, are carried out intensively around the world. The alternative fuels include biofuels. The alternative fuel that is already widely used is LPG and recently compressed natural gas (CNG) and liquid nitrogen gas (LNG) are used. An alternative gaseous fuel for diesel engines is dimethyl ether (DME) or BioDME (already produced in the world on a pilot scale), wherein the DME can be pro‐ duced from coal and BioDME from lignocellulosic biomass or even waste. It is proposed to purification of biogas to obtain clean biomethane and compressing it to a gaseous fuel with similar quality characteristics as CNG. In terms of liquid fuels, are conducted and imple‐ mented the production technologies of second-generation bioethanol from lignocellulose (waste biomass or specific energy crops) or from waste substances. Research also includes production of biobuthanol from fermentation processes and dimethylfuran (DMF) obtained from cellulose and starch; there are also contemplated the solar fuels, obtained in processes of thermal decomposition of biomass or wastes. Processes of converting biomass to liquid fuels are known as "biomass to liquid" (BtL) processes and derived from waste—"waste to liquid" (Wtl). Also contemplated are alternative fuels, which are suitably composed of mix‐ tures of synthetic hydrocarbons, obtained from a various materials—the so-called xtL proc‐ ess. Perspective raw material can be synthesis gas obtained from a wide variety of thermal processes and thermocatalytic waste substances, including biomass and energy crops, and also what is new, coming from the synthesis of water vapor and carbon dioxide. From the synthesis gas can be obtained various kinds of hydrocarbons, compositions of which will correspond to the composition of petrol, diesel oil and aviation fuels. Research is conducted on the possible fermentation of synthesis gas, leading to the preparation of ethanol and hy‐ drocarbons from C2 to C5. In the perspective there is hydrogen or biohydrogen, also ob‐ tained from synthesis gas or other biomass conversion processes, as universal energy carrier.

In terms of the most promising raw materials for obtaining of biofuels as future alternative fuels, due to the requirements for reducing CO2 emissions, there are preferred cultivations of algae, *Camelina, Jatropha* and halophytes. For increasing the amount of usable biomass raw materials, there are also being developed such technologies as without sunlight (dark) photosynthesis and marine membrane systems for the algae production and technologies for bio-methanol as raw material.

As it is clear from the foregoing considerations, there is a noticeable trend in technology de‐ velopment and research of future alternative fuels with a greater range of raw materials than biofuels, which was the guiding thought in terms of the need to develop a monograph describing these issues.

The publishing intention was therefore to develop a monograph that contains an overview of technologies of different alternative fuels, together with the presentation of current re‐ search results in the field of exploitation conditions for these fuels and the impact of opera‐ tional processes on the environment. However, currently the main research is in the field of advanced biofuels, and therefore the content of the monograph has been limited to present the views and the results of current research on gas fuel type (LPG and CNG), as well as operational and environmental conditions on the use of RME as a alternative fuel, carried out in Polish research centers. The monograph also contains a review of the possibilities for the production of selected alternative fuels derived from microorganisms, mainly microal‐ gae as a feedstock. Therefore, monograph comprises six monothematic chapters.

The first chapter is devoted to reflection on the quality and exploitation conditions of LPG fuel in spark-ignition engines. This chapter presents the results of the authors' research, es‐ pecially in terms of opportunities to reduce toxic exhaust emissions.

In the second chapter, the authors present a description of the problem and the results of their research in the field of environmental aspects of use of CNG in public transport. Re‐ search results, presented in this section, are derived from the processes of actual use of die‐ sel engines in city buses.

The third chapter describes the results of studies on the opportunities to reduce toxic ex‐ haust emissions in diesel engines of dual-fuel type, in the operating conditions. Studies con‐ ducted and presented by the authors include the possible use of gaseous fuels in the engines, while the selection of appropriate parameters determining the process of ignition of fuel dose.

The fourth chapter describes the problems and the results of research on exploitation condi‐ tions of diesel engines supplied by RME fuel in public transport, especially in the area of impact on the environment.

The fifth chapter contains a discussion on the impact of derivatives of oxygenated com‐ pounds of hydrocarbons on the fuel combustion processes in diesel engines in the field of changes in toxic exhaust emissions.

The sixth chapter is a comprehensive review on the material range of possibilities for obtain‐ ing various alternative fuels falls within the area of biofuels using microalgae as raw materi‐ als directly and also indirectly. The problems described in this section are located in the directions of development of the future technologies, advanced liquid fuels for transport.

In conclusion, on behalf of myself and the authors of this monograph, I would like to thank Mrs. Iva Simcic from InTech Publishing, for very efficient and effective completion of the publishing process as well as patience and understanding.

In terms of the most promising raw materials for obtaining of biofuels as future alternative fuels, due to the requirements for reducing CO2 emissions, there are preferred cultivations of algae, *Camelina, Jatropha* and halophytes. For increasing the amount of usable biomass raw materials, there are also being developed such technologies as without sunlight (dark) photosynthesis and marine membrane systems for the algae production and technologies

As it is clear from the foregoing considerations, there is a noticeable trend in technology de‐ velopment and research of future alternative fuels with a greater range of raw materials than biofuels, which was the guiding thought in terms of the need to develop a monograph

The publishing intention was therefore to develop a monograph that contains an overview of technologies of different alternative fuels, together with the presentation of current re‐ search results in the field of exploitation conditions for these fuels and the impact of opera‐ tional processes on the environment. However, currently the main research is in the field of advanced biofuels, and therefore the content of the monograph has been limited to present the views and the results of current research on gas fuel type (LPG and CNG), as well as operational and environmental conditions on the use of RME as a alternative fuel, carried out in Polish research centers. The monograph also contains a review of the possibilities for the production of selected alternative fuels derived from microorganisms, mainly microal‐

The first chapter is devoted to reflection on the quality and exploitation conditions of LPG fuel in spark-ignition engines. This chapter presents the results of the authors' research, es‐

In the second chapter, the authors present a description of the problem and the results of their research in the field of environmental aspects of use of CNG in public transport. Re‐ search results, presented in this section, are derived from the processes of actual use of die‐

The third chapter describes the results of studies on the opportunities to reduce toxic ex‐ haust emissions in diesel engines of dual-fuel type, in the operating conditions. Studies con‐ ducted and presented by the authors include the possible use of gaseous fuels in the engines, while the selection of appropriate parameters determining the process of ignition of

The fourth chapter describes the problems and the results of research on exploitation condi‐ tions of diesel engines supplied by RME fuel in public transport, especially in the area of

The fifth chapter contains a discussion on the impact of derivatives of oxygenated com‐ pounds of hydrocarbons on the fuel combustion processes in diesel engines in the field of

The sixth chapter is a comprehensive review on the material range of possibilities for obtain‐ ing various alternative fuels falls within the area of biofuels using microalgae as raw materi‐ als directly and also indirectly. The problems described in this section are located in the directions of development of the future technologies, advanced liquid fuels for transport.

gae as a feedstock. Therefore, monograph comprises six monothematic chapters.

pecially in terms of opportunities to reduce toxic exhaust emissions.

for bio-methanol as raw material.

describing these issues.

VIII Preface

sel engines in city buses.

impact on the environment.

changes in toxic exhaust emissions.

fuel dose.

I dedicate this monograph to my grandson, Natan, with the hope that his generation will have a sufficient amount of high-quality alternative fuels, fully environmentally friendly.

### **Prof. Krzysztof Biernat**

Automotive Industry Institute Institute for Ecology and Bioethics of Cardinal Stefan Wyszynski University Warsaw, Poland

**Chapter 1**
