While most automotive test engineers are well prepared for the switch from NEDC to WLTP this September, experts from MAHLE Powertrain believe that meeting the challenge of the new RDE regulations is imperative to future powertrain development.
As the first independent powertrain consultancy to achieve VCA approval for its real-world RDE routes, MAHLE Powertrain is in a strong position to comment on the complexities of achieving vehicle approval from this perspective.
While accommodating the various routes that include urban, rural and motorway driving is difficult enough, MAHLE Powertrain engineers have highlighted another crucial layer of test compliance that presents a significant challenge for test centres, consultancies and vehicle manufacturers alike.
Simon Williams, leader of PEMs development at MAHLE Powertrain in Northampton explains: “To certify a vehicle, it needs to pass a minimum of two tests under the RDE rules – which can be undertaken by an approved test facility or by the OEM themselves. However, a final sting in the tail rests within the legislative document for vehicle sign off that states: ‘The manufacturer of this vehicle confirms that this vehicle complies with all RDE conditions.’.”
Examining the details of the RDE conditions highlights the fact that a number of new parameters have been set, based on external temperature, altitude, speed, driver aggressivity and gradient.
In short, while the manufacturer could sign off their new vehicle using the two approved RDE tests, they also now have to ensure that this performance can be achieved across all eventualities, as laid down in the new regulations.
“Meeting RDE requirements can be challenging enough for OEMs under normal conditions, but undertaking these tests to meet the new temperature, altitude, speed, driver aggressivity and gradient measures is causing huge headaches for many in the industry,” adds Williams. “Under the new regime, OEMs will ultimately need to meet RDE emissions targets from -7 °C up to 35 °C. Similarly, tests will have to be conducted at altitudes of up to 1300 m – which is higher than Mount Snowdon or Scafell Pike. Clearly, replicating such stringent conditions consistently is a challenge that the automotive sector has yet to overcome.”
The MAHLE Powertrain team in the UK has already developed an approved real-world RDE solution, utilising PEMS (portable emissions measurement system) kits on board various test vehicles. However, given its analysis of the emerging detail of RDE, test experts from Northampton believe that upfront simulation of RDE cycles is fundamental to ensuring that RDE emissions can be achieved over all RDE conditions. These simulations can then be validated on the rolling road ensuring the most accurate, reliable and resilient simulation process for developing vehicles to be fully compliant with RDE requirements.
As well as meeting the new RDE regulations, a dyno-based solution would ensure consistency and also address the understandable concerns about time and cost. Furthermore, getting the data wrong, especially where emissions are concerned, could wreak havoc to an OEM’s reputation and profits, should a vehicle not live up to its published RDE results.
“Given the huge pressure on OEMs to achieve in-service conformity across all of their new vehicles, getting the RDE data right first time is crucial,” concludes Williams. “This far broader set of test conditions – that include the altitude and temperature elements – is not yet widely understood within the vehicle manufacturing community. However, given the tight timescales involved, we’re suggesting that OEM’s make this their number one strategic priority in 2017.”
