Diesel Part 1 – The Latest RDE2 Standards
Thursday, 2. May 2019
The hope is these latest diesel engines could offer some respite to the beleaguered fuel, turning the tide on the anti-diesel rhetoric.
However, EU law-makers, who decided to subdivide the Euro 6 standard, rather than call RDE2-compliant cars Euro 7, have not helped that cause.
When the new vehicle emissions test, WLTP, replaced NEDC for all new type approvals in September 2017, the Real Driving Emissions (RDE) test was also introduced to offer an on-the-road measurement.
The limits for emissions remained the same but the testing regime changed and was reflected in a new standard – Euro 6b became Euro 6c.
Under the RDE test, the car is fitted with a portable emission-measuring system (PEMS) before being driven for 90 minutes on public roads in different conditions, with both uphill and downhill driving, and a mix of urban and rural roads and motorways.
It is being introduced in two stages, the step 1 test – RDE1 – became compulsory for all new type approvals from September 1, 2017, when WLTP was also introduced.
RDE1 will become mandatory for all new registrations from September 1.
WLTP testing, which takes place in the lab, has been mandatory for all new registrations since September 2018, with diesel cars having to meet the NOx limit of 80mg/km and petrol 60mg/km, with cars achieving the limit labelled Euro 6c.
New type approvals, however, have also had to meet the limits on-the-road from September 2017.
The EU has cut manufacturers some initial slack, allowing for a margin of error two times the actual limit. Cars achieving RDE1 are classified as Euro 6d-temp.
However, the rules will begin tightening from January 2020, starting with new type approvals.
This next stage, RDE step two (RDE2), is the measure now being achieved early by some manufacturers, giving fleets and company car drivers the benefit of a tax cut first announced in Budget 2017.
The NOx limit for the RDE2 standard is up to 1.43 times the Euro 6 lab limit of 80mg/km for diesel and 60mg/km for petrol. Cars achieving this limit are labelled Euro 6d.
RDE2 will apply to all new registrations from January 1, 2021, before the margin for error – the conformity factor – will be removed by 2023. By Graham Hill (Thanks to Fleet News)
