History of Pollution Diesel Emission Regulation.

1

CHAPTER 1: INTRODUCTION 1.0 Background of Air pollution.

At present, there are many sources of air pollution from the combustion of fossil fuel for power plants, factories, office building, transportation and other. Air pollution can have a large negative impact on human health and the environment. The United States environmental protection agency EPA has identified six common pollutants including Ozone O 3 , Particulate Matter PM, Carbon Monoxide CO, Sulphur Dioxide SO 2 , Lead Pb and Nitrogen Oxides NOx. The sum of nitric oxide NO and NO 2 is commonly called nitrogen oxides or NOx. Over the past decade, NOx emissions have become one of the concerns due to its health impact to human. Various studies have been conducted by numerous agencies around the world to evaluate the negative impact of NOx emission to human health. The World Health Organization WHO, 2002 estimated that around 2.4 million people die every year linked to causes directly attributable to air pollution. A study at Birmingham University also revealed a strong correlation between deaths by pneumonia and traffic emissions in England. Knox, E.G. 2008

1.1.1 History of Pollution

The environmental impact of automotive pollution has led governments to enforce automotive manufacturers to reduce quantities of tail-pipe emissions. Developments of the modern automotive catalytic converter and engine management systems have been in response to these requirements. There are an increasing number of vehicles in the world today with an estimate at around 800 million [Preschern et al, 2001]. The history of the new vehicle population over a ten year period in the United Kingdom shows the growing popularity of diesel powered vehicles over petrol since 2003. This is shown in figure 1.1.1. The rise of fuel prices and the advantages of diesel-powered vehicles in term of fuel efficiency have driven this trend. 2 Figure 1.1.1 Increasing popularity of diesel powered vehicle in the United Kingdom reproduced from SMMT Motor Industry Fact 2010

1.1.2 Diesel Emission Regulation.

Diesel Emission control began in the mid 1980’s when the United States, Environmental Protection Agency EPA and California Air Resource Board CARB starting to consider emission from on road vehicles. It started after a growing popularity of diesel engine patented by Rudolf Diesel in 1892 for replacing steam engines. In the past, only Carbon Monoxide CO and Hydrocarbon HC emission from gasoline engines were regulated [Heck, 2009]. The Three-Way catalytic TWC converter technology that has been successfully used on spark ignition internal combustion engines operating at stoichiometric air-fuel ratiotypically fuelled by petrol but also sometimes fuelled by LPG, CNG, or ethanol since the middle 1980s will not function at O 2 levels in excess of 1.0, and do not function well at levels above 0.5. Since diesels operate with excess oxygen, TWC cannot be utilized to reduce NOx and alternative after treatment technology must be used. 3 In developed countries, automobiles must comply with statuary emission regulation to stay road- worthy. These are measured over a standard drive-cycle, typical of mixed driving conditions. A summary of the evolution of European emissions standards shows that future legislation will place even tighter restrictions on automotive emissions with Euro 6 NOx level at only 0.08 gkm. The evolution of European emission regulations is shown in the table 1.1.2. Table 1.1.2 Evolution of European emission regulations reproduced from DieselNet 2010 Future legislation cannot be achieved in a cost-effective manner with current diesel after treatment technology; consequently, the prospect of reducing emissions without substantially increasing vehicle cost is attractive to manufacturers. Therefore, significant efforts have been driven to further improve the diesel after treatment. Automotive manufacturers have been tested with reducing NOx emissions especially for the latest Euro 6, US Bin 5 and California SULEV regulations. 4 Figure 1.1.2 Euro 6 2014 LDD NOx regulations compared to US Tier 2 Bin 5 and California SULEV Bin2. Johnson T.V. 2009

1.2 Motivation of this thesis

The main motivation in this investigation is that the collaborating automotive manufacturers working with the Automotive Engineering Applied Research Group AEARG at Coventry University are required to find a cost effective diesel after treatment system to further reduce NOx pollution from light duty diesel powered passenger cars.

1.2.1 Aims and Objectives