An overview of emissions of reactive nitrogen compounds from modern light duty vehicles featuring SI engines

Abstract

This paper examines emissions of reactive nitrogen compounds in the exhaust gas flux of vehicles featuring spark ignition (SI) engines. A range of technical, legal and environmental aspects are considered. A discussion of the fundamentals of the phenomenona of emission of these compounds is presented, together with a brief summary of the negative environmental impacts of these gases. Selected data obtained during chassis dynamometer testing at BOSMAL are presented, together with certain important observations presented in the technical literature. The reader is directed to recent publications of note for further information on emissions to the less well known reactive nitrogen compounds, namely NH3 and N2O. The orders of magnitude of the various reactive nitrogen compounds found in the exhaust gas emitted from SI engines are briefly considered and commented upon. Data are presented on the impact of different fuel types used in SI engines and the reader is directed to various publications on that subject. Finally, important research directions (both current and future) are identified.

Measurement of Light-Duty Vehicle Exhaust Emissions with Light Absorption Spectrometers

“…However, non-zero emissions from diesel light-duty vehicles have been reported [100,107]. According to the literature, NH 3 forms within TWCs through reactions involving NO, CO, H 2 O, and H 2 as precursor molecules [84,85], particularly under rich conditions [86]. A wide temperature range between 250 • C and 550 • C where NH 3 selectivity was the highest has been reported [87].…”