A theoretical examination of the distribution of gaseous lead compounds in the exhaust from a petrol engine

✍ Scribed by Ting-man Li; R.F. Simmons

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 538 KB
• Volume: 56
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(84)90010-5

✦ Synopsis

The distribution of lead compounds in the exhaust gas from the combustion of isooctane-air mixtures has been examined theoretically for stoichiometric, rich, and lean mixtures over the range of air : fuel ratios 12.0-18.9. Two extreme conditions have been considered initially, the first being that the reactions of the lead species are essentially frozen by the adiabatic expansion associated with the power stroke. The other extreme condition is that the chemical reactions are sufficiently fast to keep the lead species in thermodynamic equilibrium as the temperature of the exhaust gas falls. These calculations show that the lead is almost exclusively present as PbO(g) down to at least 1200K, although in rich mixtures it is initially present as Pb(g) and this is converted to PbO(g) in the early part of the power stroke. It is also clear that the exhaust gas becomes supersaturated with PbO(g) before any significant lormation of lead halide can occur, so that the solid initially deposited is PbO¢s). This will react rapidly with hydrogen halide to form the relevant oxybromide or oxychloride.