טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentTzabar Nir
SubjectImprovement of Internal Combustion Engine Performance by
Oxygen Enriched Air-Supply
DepartmentDepartment of Mechanical Engineering
Supervisors Professor Emeritus Yoram Zvirin (Deceased)
Dr. Leonid Tartakovsky


Abstract

Much effort is devoted all over the world for reducing pollutant emissions from motor vehicles. Standards that limit the pollutant concentraions become stricter, forcing the vehicle producers to find creative solutions for improving the engines performance.

The goal of the present research work was to study the influence of oxygen enrichment in the intake air on diesel engine performance. One objective was to examine the assumption that oxygen enrichement in the intake air reduces the particulate emissions. The intention is to study the feasibility of developing a commercial product for this purpose.

A theoretical model, based on the basic and simplified combustion equations of a diesel cycle, was developed. The model predicts the trends and tendencies of changes in the thermodynamic properties of the intake mixture in the cylinder. Improved analysis of the engine cycle can be achieved by expending the model, to take into account the combustion kinetic.

An experimental system was built for testing a diesel engine with oxygen enriched intake air. The system includes devices for measuring particulate and NOx emissions, fuel consumption and the pressure inside the cylinder. Experiments were performed at three operating regimes: 5.4, 11.4 and 25 kW, with 21% - 30% oxygen in the intake air.

The experimental results show that oxygen enrichment in the intake air reduces, indeed, the particulate emissions. Both theoretical and experimental results show a rise in the NOx emission,  and a comparison between them proved that the theoretical model is reliable. The results of the pressure and the fuel consumption measurements indicate that oxygen enrichment during operation at low power is not beneficial.

Oxygen enrichment in the intake air might be an effective way to improve diesel engines performance. It should be considered together with a solution for the rise of NOx emission and the pressure drop in the intake manifold, in order to satisfy future requirements of emission standards.