ALTERNATIVE FUELS AND TECHNOLOGIES FOR COMPRESSION IGNITION INTERNAL COMBUSTION ENGINES

Abstract

The traditional use of fossil-based fuels is now widely considered unsustainable because of depleting their natural resources. Potential substitutes of fossil fuels are oils of renewable origin such as various vegetable and non-edible oils. The aim of using these oils or their methyl esters (biodiesel) is to establish and maintain a balance between agriculture, economy and environment protection. However, realizing the increasing demand of raw materials currently used can be achieved not only by increasing the production area but also by introducing new materials or technologies. The article presents and evaluates modern raw fuel components that are currently being investigated. Furthermore, the article deals with the dual fuel combustion technology in detail, with which the processed fuels are becoming available for use in Compression Ignition (CI) engines, where conventional blending is difficult or their use exclusively in diesel engines is economically unjustified. In case of dual fuel engine systems, the primary fuel, such as (wet)ethanol, methanol, LPG, H 2 etc. is injected into the intake manifold of the engine and the premixed mixture simultaneously produced is ignited by the pilot diesel fuel as secondary fuel injected directly into the engine cylinder. This technology can significantly reduce exhaust emissions and can slightly increase engine efficiency. The achievements in this field and recently obtained results by the author and his research group are also presented. Exhaust emissions, performance and combustion characteristics were measured and analyzed with respect to several operating parameters as follows: premixed ratio (rp), pilot timing and engine load.