End gas autoignition and knock in a spark ignition engine

The paper is concerned with end-gas autoignition, subsequent knock severity and magnitude of induced gas velocity. An optically accessed single cylinder two stroke engine was modified to give complete overhead optical access to the disc-shaped combustion chamber. Flame propagation and end-gas autoignition events were recorded using high speed natural light and schlieren photography; local gas motions, prior to and induced by the knock event, were determined using an oil droplet trajectory technique. Cylinder pressure was synchronously recorded at three positions around the cylinder head; one transducer's output being simultaneously displayed on the film. End gas autoignition generally developed from multiple centers. Autoignition was usually, but not invariably, followed by knock. The severity of knock increased as the onset of autoignition occurred closer behind the top dead centre position; knock was characterized by pressure oscillations, carbon formation and high velocity post-knock gas motions. These phenomena were relatively insensitive to mass fraction unburned at the time of autoignition.

[1]  David P. Hoult,et al.  Rapid Distortion Theory Applied to Turbulent Combustion , 1979 .

[2]  Frediano V. Bracco,et al.  Cycle-Resolved LDV Integral Length Scale Measurements In an I.C. Engine , 1988 .

[3]  John B. Heywood,et al.  Internal combustion engine fundamentals , 1988 .

[4]  John Hynes,et al.  Turbulence effects on combustion in spark ignition engines , 1986 .

[5]  J. J. Macfarlane,et al.  Soot formation rates in premixed C5 and C6 hydrocarbonair flames at pressures up to 20 atmospheres , 1964 .

[6]  John B. Heywood,et al.  Characterization of Knock in a Spark-Ignition Engine , 1989 .

[7]  George Carver Davis,et al.  The effect of in-cylinder flow processes (swirl, squish and turbulence intensity) on engine efficiency ― model predictions , 1982 .

[8]  Rudolf Maly,et al.  Role of Exothermic Centres on Knock Initiation and Knock Damage , 1990 .

[9]  Tadakuni Hayashi,et al.  Photographic observation of knock with a rapid compression and expansion machine , 1984 .

[10]  K. Korematsu,et al.  Flame Propagation into the Ring Crevice of a Spark Ignition Engine , 1986 .

[11]  Thomas Morel,et al.  Model for Heat Transfer and Combustion In Spark Ignited Engines and its Comparison with Experiments , 1988 .

[12]  M. Metghalchi,et al.  Burning Velocities of Mixtures of Air with Methanol, Isooctane, and Indolene at High Pressure and Temperature , 1982 .

[13]  H. F. Calcote.  Mechanisms of soot nucleation in flames—A critical review , 1981 .

[14]  Derek Bradley,et al.  Turbulent burning velocities: a general correlation in terms of straining rates , 1987, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[15]  Cearcy D. Miller.  Roles of Detonation Waves and Autoignition in Spark - Ignition Engine Knock as Shown by Photographs Taken at 40,000 and 200,000 Frames Per Sec , 1947 .