PERFORMANCE AND COMBUSTION CALCULATIONS FOR ENGINES UTILISING DUAL FUELS

Abstract

Due to present day energy crisis, large number of attempts are ongoing regarding utilization of different alternate_. ;fuels in engines. Dual fuel operation of Internal Combustion engines is one such area where considerable experimental work is reported.. However, the detailed analytical procedures for evaluating the performance available in literature are scanty. It is, therefore, proposed to model the.closed cycle processes of a multifuel pre-mixed charge engine. In the present work, systematic combustion Calculations for a premixed multifuel-air cydle assuming Constant Volume Combu-stion are carried out. A generalised combustion equations are written on an equivalent fuel basis for various fuel fractions in the total fuel-air mixture of the engine charge. The study is an initial attempt at theoretically predicting .engine performance in terms of values of thermodynamic properties at all cardinal points and mean effective pressure and thermal effi-ciency. The variety of conditions are chosen for comparision viz., initial temperature, compression ratio, equivalence ratio and residue fraction, at various compositions of the fuel mixtures. The fuel air cycle calculation values for the base fuels (C8 H18 and C8 H16) data are compared with available results of earlier works. The investi-gation is further extended to iso-octane..methanol and iso-octane-ethanol mixtures and results plotted. The multifuel-air cycle Calculations predict--the trends in each cases within the limitation of simplified assumptions. The trends of the results conform to many experimental investigations and the results are in-general matching with.the available data on base fuel-air cycle. (