Emissions Analytics, an independent commercial test house, has built an impressive inventory of real-world emissions data using a Portable Emissions Measurement System (PEMS) to analyse true in-use performance of passenger cars
This data resource, from tests on more than 800 vehicles, is transforming the economics of obtaining emissions data for OEMs who are tasked with understanding and acting upon the proposed legislative changes concerning Real Driving Emissions (RDE) and the move towards the World Harmonised Light Test Cycle and Procedures (WLTC/P).
The new testing system, developed by global representatives for the United Nations Economic Commission for Europe is due to be finalised in the spring of 2015. This test cycle is more representative of real-world driving and the test procedures should be more robust than those associated with the New European Drive Cycle (NEDC).
One of the reasons for the proposed change is the growing gap between the number of miles per gallon certified during the NEDC test and the fuel economy achievable by real drivers on the road. Much has been written on the subject recently, including Transport and Environment’s report Mind the Gap, which describes how manufacturers hyper-optimise for the test and the consequences this has for ordinary consumers.
Using Emissions Analytics’ real-world data, the blue line on the graph below illustrates how this gap is growing, at about two percentage points per year, and is likely to continue to expand if left unchecked. With the introduction of the WLTC/P in 2017, the gap is predicted to close by between half and two-thirds (shown below in green), depending on how stringent the final protocol is.
Interestingly, Emissions Analytics, which also tests vehicles in the USA from a base in Los Angeles, predicts this will bring the European divergence closer, but still not equal, to US variances. The US uses a more stringent five-test system, which tests the envelope of performance modes, reducing the opportunities for so-called gaming and issuing significant financial penalties for manufacturers caught out by spot checks.
The European Parliament and European Commission have proposed this new test be introduced in 2017, although there are obstacles and opposition from some parts of the automotive industry that would like longer to adapt to the changes.
One of the challenges facing OEMs is the profile of the NEDC replacement, the WLTC. In an October 2014 report by the International Council on Clean Transportation (ICCT), it is estimated, “that the effect of the WLTP on the EU CO2 target value will be an increase of around 5%-8%”. The ICCT goes on to calculate that if applied to the NEDC based 95g/km CO2 target, due to come into effect in 2020-21, “the resulting target value in WLTP would then be 100g/km (without temperature correction) and 102g/km (including temperature correction)”.
In other words, based on current technology, engines achieving 95g/km will, when tested on the new cycle, only achieve 100-102g/km. Emissions Analytics believes the increase could be higher than this. If nothing were changed in the targets, OEMs would need to deliver further efficiencies in their vehicles, and consumers in some countries could find themselves paying more vehicle tax.
There is a methodology under development for translating the existing NEDC results into WLTC, but this is still work-in-progress and has limitations. What is clear is that forewarning of how current vehicles perform on the test can bring significant benefits to the engineers developing the vehicles which will be on the road when the WLTC/P is adopted. This is why some manufacturers use Emissions Analytics’ data to ensure compliance and to stay competitive, benchmarking their own progress against that of their closest rivals (as seen below).
Another issue facing the industry is the introduction of in-use compliance testing designed to validate type approval NOx results. In another report by the ICCT, also published in October 2014, which included six of Emissions Analytics’ datasets on Euro 6 diesels, the average NOx emissions of the vehicles investigated were more than seven times the Euro 6 limit. Each of the 15 vehicles included in the report was type approved but in real-world use all but one failed to meet the legislative limit and therefore they would likely also fail a spot check.
However, it should be noted that in our most recent data, the NOx picture is already improving, with the latest cars showing an average exceedance of four times the regulated value. This is a similar exceedance ratio that was seen with Euro 5 diesel cars. This improvement in recent Euro 6 is a result of OEMs optimising their NOx abatement systems, for example urea dosing rates.
Emissions Analytics has been carrying out its PEMS testing for three years, working with What Car? in the UK and Motor Trend in the USA to deliver a real-world fuel consumption tool consumers can trust. It will be making the data available to the automotive sector directly via a new, subscription-based software platform called RDEanalytics. As described in the examples above, OEMs and others will be able to query the database to identify how their vehicles perform currently, how they are likely to perform in the future and how they compare to their competitors.
In times when manufacturers are under increasing pressure to be open and honest about their vehicles’ true in-use performance, plus with the imminent legislative changes which will formalise this requirement, there has never been a greater need for a reliable and robust source of data which can offer the insight and intelligence needed.
