الفهرس 
INTRODUCTION AND PREVIOUS WORKOnly 14 pages are availabe for public view
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Abstract
Investigations have been carried out in order to improve the emissions and fuel consumption of spark-ignited engines. These studies have shown that a possible future for the evolution of the gasoline engine is a combination of lean combustion (A/F ratio = 18 : 1) and high compression ratio (CR = 14 : 1). Several modifications in the geometry of the combustion chamber and inlet manifold must be made to achieve satisfactory operation at these conditions. The principle of these modifications is to decrease the ignition period especially as these engines are required to operate on the lean side in order to achieve high efficiencies and meet the future air pollution regulations.
Since the concentration of carbon dioxide in the exhaust gas emitted from a spark ignition engine is directly related to the A/F ratio. It was proposed that the measured CO2 signal could be used to control the A/F ratio at the desired level.
The objective of the present work was firstly to study and design suitable arrangement to detect the variation of CO2 in exhaust gases in a short time and with sufficient accuracy at low cost.
The concept of infra-red radiation absorption was applied in this work to detect the CO2 concentration. The parameters which affect the accuracy of measurement were examined. In addition, the time response of the I.R. detector for different CO2 concentration levels was compared with that of a commercial Co2 Grubb Parsons Analyser (GPA) which was connected in parallel with the I. R. detector. The measured values of CO 2 were al so compared with the predicted values for different A/F ratios.