COMBUSTION-CHAMBER DEPOSITS—A RADIOTRACER STUDY

Abstract

<div class="section abstract"><div class="htmlview paragraph">AN IMPORTANT effect of combustion-chamber deposits is their tendency to raise the engine's need for higher octane fuels; also, they may cause uncontrolled ignition of the fuel-air mixture and misfiring of spark plugs. This paper describes a new approach to this problem.</div><div class="htmlview paragraph">By means of radioactive hydrocarbons, present in tracer amounts, the authors have been able to conclude the following about the effect of gasoline hydrocarbon composition on deposit formation in the combustion chamber: <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">The deposit-forming tendency of hydrocarbons goes up strongly with increasing boiling point.</div></li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">Aromatics are considerably worse deposit formers than paraffins. Olefins are intermediate.</div></li> <li class="list-item"> <span class="li-label">3.</span> <div class="htmlview paragraph">The carbonaceous part of combustion-chamber deposits appears to form via a mechanism involving condensation followed by carbonization.</div></li> <li class="list-item"> <span class="li-label">4.</span> <div class="htmlview paragraph">Careful control of the back-end is needed to make a clean-burning gasoline.</div></li></ol></div></div>