Automotive Engineering Commons^™

Effects Of Variable Valve Actuation On Exhaust Enthalpy And Engine Out Emissions, Zakarie Parker

Dissertations, Master's Theses and Master's Reports

Vehicle emissions standards are becoming increasingly more strict as time progresses. Once all of the emissions devices are in their operational stage, these standards can be met with reasonable effort in powertrain design and calibration. However, the core of this system, the three-way catalyst, is non-operational until it has reached 200-350⁰C. Because of this, cold-start catalyst heating is extremely important in new vehicles. The objective of this project was to improve catalyst heating without increasing engine-out emissions. It was decided that the sensible heat portion of the exhaust enthalpy would be the best metric to judge differences between the different …

Reduction Of Nox Emissions In A Single Cylinder Diesel Engine Using Sncr With In-Cylinder Injection Of Aqueous Urea, Anthony Timpanaro

UNF Graduate Theses and Dissertations

The subject of this study is the effect of in-cylinder selective non-catalytic reduction (SNCR) of NO_x emissions in diesel exhaust gas by means of direct injection of aqueous urea ((NH₂)₂CO) into the combustion chamber. A single cylinder diesel test engine was modified to accept an electronically controlled secondary common rail injection system to deliver the aqueous urea directly into the cylinder during engine operation.

Direct in-cylinder injection was chosen in order to ensure precise delivery of the reducing agent without the risk of any premature reactions taking place. Unlike direct in-cylinder injection of neat water, …