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SMAT2008E13EXPERIMENTAL RESEARCES REGARDING THE DIRECT INJECTIONIN HYDROGEN FUELED S.I. ENGINENiculae NEGURESCU 1 , Constantin PANA 1 , Marcel Ginu POPA 1 ,Alexandru CERNAT 2 , Dorin SOARE 3Abstract: Hydrogen represents an adequate fuel for spark ignition engines due to its wide flammability limits and itshigher burning rate which provide engine stable operating conditions at very lean air-fuel mixtures. Thus is possible toassure the engine load qualitative adjustment (opened full throttle) instead of load quantitative adjustment, providingalso the decreasing of the pumping mechanical work.Hydrogen engine performances are directly related to the usedfuelling method and to the applied operating strategy.The paper presents the results of the experimental researches carried on SI single cylinder engine fuelled withgasoline and hydrogen addition in different proportions and also only with hydrogen. Hydrogen is admitted inside thecylinder after intake valve close thru a hydrogen valve mounted into the engine cylinder head. The hydrogen valve isactuated by a hydraulic system which provides the possibility to adjust the valve opening duration and valve openingmoments, assuring a high flexibility of system tuning. The inlet of the hydrogen after the admission process provides thein-cylinder cooling effect avoiding spontaneous ignition phenomena. Another advantage of this fuelling method is thatthe inlet air quantity is not reduced. The main goals are the increase of the engine efficiency and the decrease of thepollutants emissions level, in conditions of maintaining at least the same density of power as gasoline engine.Are presented the engine performances at the fuelling with gasoline and hydrogen addition or only hydrogenand also are analyzed the influences of some adjusting parameters (dosage and hydrogen percent) on energetically andpolluting performances of the engine.Keywords: hydrogen, direct injection, hydraulic system, spontaneous ignition, hydrogen additionSMAT2008E17ATTENDING ENGINE BY COMPUTER IN ORDER TOREDUCE POLLUTANT EMISSIONSMarius STOICAN, Marin BICĂ, Corina Dana CERNĂIANUAbstract: Because the imposed pollution limits are lower and lower, it appears the necessity of fuel mixturemanagement by computer (ECM) more efficient. This paper shows the mode of operation of an ECM with factorsinfluences the fuel mixture, respectively, on emissions.Keywords: pollution, ECM, control1 Professor, Internal Combustion Engines, University Politehnica of Bucharest,ROMANIA, e-mail:nnegurescu@yahoo.com2 PhD student, Internal Combustion Engines,,University Politehnica of Bucharest,ROMANIA3 PhD student,University of Pitesti, ROMANIA48