Abstract
European Directive 99/96/EC sets heavy-duty diesel engine gaseous and particulate matter limit values for 2005 (Euro IV) and 2008 (Euro V). The NOx limit values for 2008 are required to be the subject of a technical review by the European Commission to confirm that the technologies required will be proven. This review has to be published before the end of 2002.
This project has been carried out to investigate the feasibility of achieving the Euro V emission limits of 2.0 g/kWh NOx and 0.02/0.03 g/kWh particulate matter for introduction in 2008 using emission control technologies already developed by members of the Association for Emissions Control by Catalyst but without a programme to optimise their performance as a combined system.
A modern heavy-duty diesel engine was equipped with an integrated catalyst based diesel particulate filter (to remove particulate matter including ultra-fine particulates), a urea-based selective catalytic reduction system (for a high level of NOx reduction) and a clean-up catalyst (to eliminate any ammonia slip). The emission control system was tuned to meet an engineering target of around 1.0 g/kWh NOx (i.e. 50% of the Euro V limit value), with very low particulate matter levels below 0.01g/kWh, and then aged for 1000 hours over an accelerated durability test cycle. The ageing test was designed to simulate real world driving conditions including exposure to higher levels of fuel sulphur than those promulgated in the European Union for 2008, to establish the emission deterioration factors and to demonstrate stable emission levels.
This paper reports the results of the emission measurements before and after the ageing test, with regulated emissions at below 50% of the proposed 2008 limit values after 1000 hours, and also reports unregulated emissions and the observations made during the ageing procedure. Engine-out and exhaust-out emissions of unregulated emissions of aldehydes, ammonia, nitrous oxide and nitro-polyaromatic hydrocarbons were measured and excellent levels of control established.