Combustion Chamber Of Spark Ignition Engine Research Articles

Wavelet analysis of turbulent velocity fields in a spark ignition engine

The issue of decomposing in-cylinder flow into mean and turbulence velocities remains unresolved. Spark Ignition (SI) engine flows are inherently non-stationary because of the piston and valve motions. In SI engine combustion chamber, turbulence is superimposed on unsteady organised motion of a mean flow. These turbulent flows have been studied by time or ensemble averaging methods and low-pass, high-pass filter methods. In this study, wavelet transform has been applied to experimentally measured turbulent velocity field in an SI engine to extract information about coherent structures. The radial and circumferential turbulent velocity fields are measured using hot wire anemometer under motoring conditions at various engine configurations.

Turbulent Premixed Flames in a Spark-lgnition Engine. (Study by Analyzing Ion-Current Waves).

In a pentroof type combustion chamber of spark-ignition engine, a tumbling flow is broken down to small scale eddies near the top dead center in compression stroke and promotes the flame propagation. The effects of tumbling flow and its turbulence on combustion were investigated by analyzing combustion pressure and ion-current wave form. The number of peaks of ion current wave N^-p increases with the increase in turbulence intensity. The mean rate of heat release in the early stage of combustion increases linearly with the increase of N^-p. The spacing of flamelet surfaces in burning zone of turbulent flame decreases with the increase in turbulence intensity.

Determination of empirical formula for instantaneous heat transfer coefficients in a S. I. engine

A new empirical formula for instantaneous heat transfer coefficients was determined. The determination of this formula is in need for prediction of instantaneous value of heat transfer coefficients to analyze in more detail the time variation of heat transfer rate from gas to wall in combustion chamber of a spark ignition engine. As the result, following formula was determined. h=687 - U(.theta.)=O.494 +0.73*10 (1.35 p dV/d.theta.+V dp/d.theta.) Using this empirical formula, the instantaneous heat transfer coefficients of gas in the combustion chamber of spark ignition engine was predicted and compared with experimental values.

Planar Measurements of the Fuel Vapor Concentration in the Combustion Chamber of SI Engine with Laser-sheet-Induced Rayleigh Scattering.

An experimental study was made of the planar measurements of fuel vapor concentration in the combustion chamber of a spark ignition (SI)engine with laser-sheet-induced Rayleigh scattering. The conventional engine was modified to introduce YAG laser sheet light into the combustion chamber. The scattered light from the measuring plane was allowed to transmit an optical glass window installed on the extended piston and captured with a CCD camera fitted with a gated doublemicrochannel-plate image intensifier by lens coupling. The time histories of fuel vapor concentration distribution and the effect of injection methods on them were investigated thoroughly. It was found that the fuel vapor concentration was highly heterogeneous during the intake stroke, and the inhomogeneity decreased in the compression stroke. However, even at the end of the compression stroke, small lumps of unhomogeneous mixture still existed randomly inside the engine combustion chamber.

Time Resolved Local Gas Composition in a Combustion Chamber of Spark-Ignition Engine

Time Resolved Local Gas Composition in a Combustion Chamber of Spark-Ignition Engine