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13/07/2016
Dieselgate – New emission tests for the EU

Massimo Brunamonti

Issues around harmful emissions are far from over; politicians and national authorities are all striving to address the indignation that the Dieselgate aroused in citizens throughout Europe and beyond. Finally, the first few steps in that direction seem to have been taken.

On January 27, 2016, the European Environment Agency (EEA) released its official report on motor vehicle emissions in Europe. The report, explains how these emissions are monitored and what are the technologies available and commonly used to limit them.

The road transport sector is a major source of greenhouse gas emissions and air pollution. The fact is that some vehicles currently running on our road produce considerably higher quantities of harmful emissions compared to laboratory test results. Despite undeniable recent improvements, a variety of factors such as ad hoc legislations, speed limits, technological developments, etc., the road transport sector, as the EEA report clearly shows, is still responsible for generating almost a fifth of the total greenhouse gas emissions in Europe and contributes, in many European cities, to raise the concentrations of air pollutants above the permitted limits.

'Vehicle emission tests are a rather complex issue, one that has been widely discussed in the media in recent months', said Hans Bruyninckx, EEA executive director. 'This report explains in simple terms how harmful emissions take place, how they are tested, and the reasons for the gap between laboratory results and real driving emissions'.

Measurements performed during vehicle approval tests are performed in a laboratory by simulating real driving conditions and verifying that vehicles comply with standard requirements. However, it is now quite evident that the official NEDC procedure, currently used in Europe, does not really represent real life driving conditions, as highlighted by the now infamous Dieselgate, but it is actually so weak that many could potentially take advantage of it. In other words, for some pollutants, the difference between laboratory and on-road measurments is quite significant.

The EEA report identifies three main causes for this discrepancy: the first, as already mentioned, relate to test procedures that do not represent real driving conditions. A second cause relates to the "flexibility" granted during lab tests which allow manufacturers to "optimize" some test conditions. The role played by these “optimizations” becomes clear if we consider that the latest generation of vehicles, in real driving conditions, end up producing seven times more nitrogen oxides (NOx) than normal and up to 40% more carbon dioxide (greenhouse gas) compared to official lab results.

This allows car manufacturers to advertise the fuel consumption and CO2 emissions of their vehicles using official lab test results; such information is then used by customers in making their own choices. Too bad that  the reality is quite different. It is no coincidence then, looking back at the famous Dieselgate, which saw one of Europe’s largest car makers involved, that in addition to the environmental damage, the real issue has to do with consumer fraud; Now, finally, politicians as a whole have decided to deal with it.

What about the third factor? A decisive element in the difference between laboratory data and real driving conditions, is simply one: "reality". Factors such as the driver, driving style, weather, traffic, etc. all play a major role in explaining the different emission results.

It is clearly impossible to reproduce in a lab all the variables found in real driving conditions, thus, two major solutions have been identified in the EU to help ensure compliance of the official emission tests with real life performance: updating approval test procedures is the first, current ones are quite obsolete and must be substituted by more modern systems which can truly represent real emissions. The second, is the introduction of NOx road side emission tests.

As you might recall, the European Union has recently approved a procedure for real driving tests (Real Driving Emissions) for cars and vans. With this solution, the EU will become the first region in the world to use road side emissions tests for the sole purposes of guaranteeing  legal compliance.

The new RDE procedure will focus at first on NOx emissions and later on particulates, using portable, on-board measuring tools. The RDE protocol provides that the emissions measured in real driving conditions should be lower than the legal limit multiplied by a 'compliance factor', taking into account both the  vehicle’s current condition as well as its natural deterioration. The compliance factor will be determined by the legislator following a consultation with the manufacturers.

As the EEA report concludes, these inspections, along with initiatives aimed at encouraging the development and adoption of clean technologies in the transport sector, are critical in reducing the impact of transport vehicles on both our health and the environment, promoting the development of a green economy in Europe.

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