The European regulations for new heavy-duty diesel engines are commonly referred to as Euro I ... V. The Euro I standards for medium and heavy-duty engines were introduced in 1992. The Euro II regulations came to power in 1996. These standards applied to both heavy-duty highway diesel engines and urban buses. The urban bus standards, however were voluntary.
In 1999, the European Parliament and the Council of Environment Ministers adopted the final Euro III standard (Directive 1999/96/EC of December 13, 1999, amending the Heavy Duty Diesel emissions Directive 88/77/EEC) and also adopted Euro IV and V standards for the year 2005/2008. The standards also set specific, stricter values for extra low emission vehicles (also known as "enhanced environmentally friendly vehicles" or EEVs) in view of their contribution to reducing atmospheric pollution in cities.
In April 2001, the European Commission adopted Directive 2001/27/EC which introduced further amendments to Directive 88/77/EEC. The new Directive prohibits the use of emission "defeat devices" and "irrational" emission control strategies, which would be reducing the efficiency of emission control systems when vehicles operate under normal driving conditions to levels below those determined during the emission testing procedure.
It is expected that the emission limit values set for 2005 and 2008 will require all new diesel-powered heavy duty vehicles to be fitted with exhaust gas aftertreatment devices, such as particulate traps and DeNOx catalysts. The 2008 NOx standard will be reviewed by December 31, 2002 and either confirmed or modified, depending on the available emission control technology.
Changes in the engine test cycles have been introduced in the Euro III standard (year 2000). The old steady-state engine test cycle ECE R-49 will be replaced by two cycles: a stationary cycle ESC (European Stationary Cycle) and a transient cycle ETC (European Transient Cycle). Smoke opacity is measured on the ELR (European Load Response) test.
For the type approval of new vehicles with diesel engines according to the Euro III standard (year 2000), manufacturers have the choice between either of these tests. For type approval according to the Euro IV (year 2005) limit values and for EEVs, the emissions have to be determined on both the ETC and the ESC/ELR tests.
EU Member States will be allowed to use tax incentives in order to speed up the marketing of vehicles meeting the new standards. Such incentives have to comply with the following conditions:
they apply to all new vehicles offered for sale on the market of a Member State which comply in advance with the mandatory limit values set out by the Directive,
they cease when the new limit values come into effect (i.e. in 2000, 2005 or 2008)
for each type of vehicle they do not exceed the additional cost of the technical solutions introduced to ensure compliance with the limit values.
A new proposal, to be submitted by the European Commission by 31 December 2000, should include:
rules pertaining to the introduction of an on-board diagnostic system (OBD) for heavy-duty vehicles from October 1, 2005 (similarly as provided for in Directive 98/69/EC on the reduction of exhaust emissions from passenger cars and light commercial vehicles),
provisions on the durability of emission control devices with effect from October 1, 2005 (to ensure that they operate correctly during the normal life of a vehicle),
provisions to ensure the conformity of in-service vehicles which are properly maintained and used,
appropriate limits for pollutants currently non-regulated as a consequence of the widespread introduction of new alternative fuels.