Liquefied hydrocarbon gases, containing mostly the mixture of C3-C4 hydrocarbons, in many countries serve as an important source of energy, also for internal combustion engines. On a world scale, at present, about 270 million tonnes of this fuel is produced, of which motorization consumes 26 million tonnes (~10%). Poland is one of these countries, where LPG is a popular engine fuel. Annual consumption of so called autogas is about 1.7 million tonnes with increasing tendency. Almost 3 millions of cars with bifuel engines, mostly spark ignition ones, are driven on Polish roads. An extensive logistical infrastructure accompanies the development of the use of this type of fuel in Poland. There are numerous production companies in Poland working to meet the needs of this branch of industry, as well as a modern service base. Intensive research and development works in this field are carried out. The exceptional advantages of LPG as an alternative engine fuel have been highly appreciated in Poland. These advantages result mainly from the simplicity of its production. Relatively low investment costs and energy consumption are needed to produce high-quality fuel by degasolining of natural gas or crude oil stabilization. LPG is produced as a byproduct in numerous petroleum refining processes and its quality is relatively close to the engine fuel requirements. The source of aliphatic hydrocarbons falling into LPG range can also be the processes of biomass conversion and in the near future, fermentation processes. Environmental advantages of LPG are primarily very low emission of almost all toxic components of engine exhaust gases compared to gasoline or diesel fuel. In this chapter the results of research works aimed at the improvementof exploitation properties, logistics and LPG combustion processes in spark ignitionengines are presented. In this area, anti-corrosion additives for LPG of very high effectiveness were obtained and tested. Also, with the help of additives, the problem of water separating from LPG during storage and transport in tankers has been solved. A multifunctional additive was obtained giving LPG adequate lubricity and detergent properties. The influence of water on the process of LPG combustion in a gasoline fuelled engine as well ways to supply water to the combustion zone are being studied. A mathematical model is being elaborated, precisely describing correlations between density and chemical composition of LPG as well as changes of density as a function of fuel tempera- ture. In the realization of these plans LPG producing companies, research and development teams as well as producers of automobile LPG systems are involved. Successful completion of research works and design works will result in elimination of scarce disadvantages of LPG as an engine fuel, preserving at the same time all its numerous advantages as an alternative fuel for the future -the new era source of energy.

Przeanalizowano informacje literaturowe dotyczące dodatku wody w różnych postaciach do czynnika roboczego silnika zasilanego paliwem LPG. Opisano korzyści płynące z dodawania wody do silników o zapłonie zarówno iskrowym, jak i samoczynnym, zasilanych paliwem LPG, w tym wpływ na parametry operacyjne silnika oraz na emisję zanieczyszczeń. Ocenia się, że dodatek wody do czynnika roboczego ma korzystny wpływ na sprawność cieplną obiegu, przyczynia się również do zmniejszenia emisji tlenku węgla, węglowodorów i tlenków azotu. Przedstawiono metodykę badań empirycznych silnika o zapłonie iskrowym zasilanego paliwem LPG z dodatkiem wody: badania przeprowadzono w warunkach symulujących trakcyjne użytkowanie silnika – w homologacyjnym teście jezdnym – NEDC, składającym się z testu jazdy miejskiej – UDC i pozamiejskiej – EUDC. Przedstawiono charakterystykę paliwa stosowanego w badaniach: jego skład i wybrane właściwości fizyko-chemiczne. Przedstawiono wyniki badań empirycznych: zużycia paliwa i emisji zanieczyszczeń. Stwierdzono, że dodatek wody ma wpływ na zmniejszenie eksploatacyjnego zużycia paliwa oraz emisji drogowej tlenku węgla, węglowodorów, tlenków azotu i dwutlenku węgla w warunkach pracy silnika odpowiadających jeździe zarówno miejskiej, jak i pozamiejskiej.