Ignition of Premixed n-heptane within Air by a Low Speed Motoring Compression

Abstract

In this paper correlations of the ignition starting gas law temperature and molecular concentration instead of a critical compression ratio were obtained under the conditions ; premixed n-heptane and air, equivalence ratio (S) : 0.5∼3, mean piston speed : 1 m/sec, without residuals, lubricant : molybdenum-disulphide. The pressure was so high that the reaction was automatically led to a hot flame after τ1 regime. Thrice stoichiometric charge also actively burnt consuming oxygen as well as at a stoichiometry, nevertheless pressure rise rate was less than that. Cool flame starting temperatures, ignition triggers, were in a narrow range of 400∼430°C over S=0.5∼3. Shapes of indicator diagram are two-stage ignition at S=0.5, single stage ignition at S=2, 3. At S=1, two-stage ignition obviously at the molecular concentration of 0.21 kmol/m3, and at 0.43 Kmol/m3 two-stage but similar to single stage ignition.