Emissions – the facts

Audi A3 on test, fitted with Emissions Analytics PEMS equipment
Audi A3 on test, fitted with Emissions Analytics PEMS equipment

Car emissions have never been far from the headlines in recent months following the disclosure of Volkswagen’s misdeeds with so-called “defeat devices”.

The irony of the media hysteria is that they have so far only been able to report on how well cars comply with EU emissions laboratory tests. These are entirely unrepresentative of the emissions produced in everyday driving on the road. Why? – because there has been no agreed way to measure emissions produced during normal driving, and certainly no way to compare everyday emissions between different makes and models of car.

“This has resulted in confusion”

This has resulted in confusion.  Are all diesels dirty?  Are all Volkswagen’s well over the regulated limits?

All vehicles running on diesel or petrol emit air polluting nitrogen oxides (NOx), but the amount varies significantly from car to car. While vehicle emissions are important for air quality and health, Europe is currently in the position that the official data does not measure real-world emissions, and data from manufacturers is piecemeal and not independent. The EU process for official certification of vehicles is being improved from 2017 with the introduction of some on-road testing into the process.

Therefore, while there is a need for car buyers to know what they are buying, there has been no way to help them make an informed decision.

Until now.

how PEMS works

a simple graphic, but much technical innovation has gone into developing the PEMS equipment and procedure

 Emissions Analytics, a specialist in real-world, on-road vehicle emissions measurement and analysis, have developed the EQUA Air Quality Index. This evaluates the performance of individual passenger cars in terms of nitrogen oxide (NOx) emissions under real-world driving conditions on a standard, proprietary test route.  The route covers a mix of urban, rural and motorway driving, designed to reflect typical – rather than extreme – driving styles.  Each car is tested in the same way, by the same team of drivers, within a consistent range of climatic conditions.  All tests are checked for data quality and consistency to ensure the EQUA Index is a fair reflection of performance. In short,the EQUA Index seeks to sort the good from the bad in a simple, clear way.

“The equipment is the same as that used for official testing”

The measurement equipment used is called a Portable Emissions Measurement System: a high-grade on-board gas analyser that measures to a high degree of precision, second-by-second, what comes out of the exhaust pipe.  The equipment is the same as that used for official compliance testing.

The EQUA Air Quality Index clearly identifies vehicles emitting the lowest quantities of nitrogen oxides (NOx) on a scale from A (best) to H (worst). At the time of writing, some 470 cars have been tested, with more being tested regularly.

“The EQUA Index is free to use”

Best of all, the EQUA Index is free to use, and can be found at www:equaindex.com

EQUA emissions label

A typical EQUA Emissions label – soon to become a common sight?

Although the EQUA Index data does confirm that almost all diesels, even at the latest Euro 6 level, produce much more NOx emissions than petrol engines, a browse through the EQUA Index reveals some surprising results. For example, among the lowest emissions diesel engines is none other than the ubiquitous Volkswagen Group 2 litre unit as found in numerous VW, Skoda, Audi and Seat brands. This engine achieves the highest “A” rating, almost unique amongst the current crop of diesels in doing so, most competitors achieving at best only a “D” rating, with many much worse.

As expected, small capacity petrol engines, which are becoming increasingly common, generally score well, with most, but not all, Euro 6 versions achieving an “A” rating. Surprisingly, though, earlier (2015) Euro 6 versions of the 1. 0 litre Ford Focus engine managed only an “E”, although revisions to the engine in 2016 saw the engine achieve the benchmark “A” rating. Producing roughly 85% less NOx when recently tested, the new rating shows that vehicle manufacturers are making noticeable improvements to engine performance as air quality issues come under closer scrutiny. As Nick Molden, CEO and founder of Emissions Analytics, comments: “It’s encouraging to see that vehicle manufacturers are cleaning up engine emissions as part of a continuous development programme. Both large and small displacement engines are capable of hitting the latest targets if correctly optimised.”

“Emissions can be low even on the largest engines”

Underlining the fact that emissions can be low even on the largest of engines, the new Bentley Bentayga 6.0-litre W12 and Rolls-Royce Dawn 6.6-litre V12 have also received an EQUA Index A rating. Surprisingly, the low emissions of both engines mean they produce less NOx than every one of the Euro 6 diesel engines listed on the EQUA Index.

So, if you are in the market for a new car, or are interested in seeing the facts behind emissions, head over to www:equaindex.com for a browse. The numbers might surprise you!

Audi A3 on test, fitted with Emissions Analytics PEMS equipment

Audi A3 on test, fitted with Emissions Analytics PEMS equipment

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