The ACCC is calling for the introduction of real-world fuel consumption testing, but there’s a better way, says the UN.

THE ACCC is using data collected by the Australian Automobile Association (AAA) to call for the Government to introduce real-world fuel consumption testing of new cars. The AAA grabbed a handful of cars, attached pollution gear and drove them around Melbourne, finding that fuel consumption was up to 23% higher than claimed by laboratory tests.

“Our research shows fuel consumption is the third most significant purchasing factor for consumers after price and model. We are concerned that new car buyers are not receiving accurate information about fuel consumption or emissions performance,” ACCC boss, Rod Sims said in a statement.

But is the ACCC misunderstanding the current approach, being able to compare apples with apples, and a United Nations developed lab test that’ll be introduced into Europe in 2020. The answer is, yes.

If you’ve bought a new car recently you’ll have noticed a colourful sticker on the windscreen showing the fuel consumption and the emissions. These numbers are generated via a lab-based test which see a car plonked onto a dynamometer, or rolling road and tested for up to 20 minutes. All cars arriving in Australia undergo the same test protocol and, so, technically, fuel consumption is an even playing field in this country. Sure, it might not reflect the fuel consumption you’d achieve on your drive to and from work, but it does at least allow you to compare one car with another.

The dynamometer-based testing mandated under ADR81/02 is a simple 20-minute cycle that’s split into two sections. These are:

Phase One (10 minutes) is better known as the Urban Cycle and involves a peak speed of 19km/h, frequent stop-start moments, and idle periods (up to three minutes). This test is intended to simulate situations experienced in stop-start traffic.

Phase Two (10 minutes) is better known as the Extra-Urban Cycle and this involves the vehicle being accelerated to achieve an average speed of 63km/h with speeds peaking at 120km/h (for just 11 seconds). Some might suggest the test should be conducted at a constant speed of, say, 100km/h for a more accurate simulation of real-world use… but, when this testing methodology was introduced in Europe in 1997 the differential between the lab results and the real world was only about 10%, now the differential is up to 30%.

Once the two fuel consumption figures have been calculated, these are then combined to determine the combined average fuel consumption across 100km, and the vehicle’s average CO2 emissions per kilometre.

The ACCC is pushing for the Government to mandate a real-driving fuel consumption and emissions test. This would cost an extraordinary amount of money and where would the testing take place? In Sydney? In Melbourne? Bathurst, NSW? And because the road loop would be in the real-world it’s repeatability and consistency wouldn’t be quite the same as when performed in a lab.

Indeed, rather than an expensive and non-repeatable and potentially non-relevant real-world fuel consumption test (consider a Peugeot real-world tested in Paris and the results applied to cars sold in Australia; the result would largely be meaningless) the UN suggests a new lab-based test.

The United Nations has developed the Worldwide Harmonized Light Vehicles Test Procedure (WLTP), something it’s been working on since 2007 (a couple of years before Australia introduced the then 10-year-old measurement method of NEDC – New European Driving Cycle), because it claims the gap between the current lab-based dynamometer (rolling road) test and real-world fuel consumption is up to 30%.

WLPT is set to replace NEDC in Europe from 2020 with claims it will have a significant impact on fuel consumption (bringing it closer to a real-world result but with the consistency of a lab test) because it would disallow vehicle modifications which are allowed under current testing, and introduce a more dynamic testing regime.

For instance, there will no allowable changes to tyres, in that they must be the tyres the vehicle will be sold with, they must contain within 80-100% of their tread depth, they cannot be pre-warmed, the tyre pressure must be the recommended psi for the tyre, the wheel alignment must be as per how the vehicle will be sold, the vehicle body must be stock standard, and the same for the brakes. And the ‘warm-up’ period will be 20 minutes at 118km/h. The vehicle’s test weight will be kerb weight plus 100kg.

In short, the aim is to provide a greater dynamic driving range over a longer period of time with more real-world ambient temperatures in the laboratory, conducted with stock standard vehicles with no modifications and maximum weight applied. For instance, the run times will increase and the stop times will decrease, meaning stop-start systems will no longer be able to skew results. Constant driving times will be reduced (down from 40.3% currently to just 3.7%) with more focus on acceleration and deceleration periods (43% and 39%, respectively).

Question: Should the ACCC spend a little more time researching fuel consumption testing before shooting off, and should Australia introduce the UN-developed lab test protocol?


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1 comment

  1. Sorry I disagree, it’ doesn’t show a relative performance because it doesn’t test how differently cars behave when being pushed. Take the Merc A45, with it’s BS sticker that claims 7.6l/100km or thereabouts and Commodore SS, which claims 14l/100km or so. Gee the Merc is twice as good, except when you actually use the performance the Merc uses about 14l/100 and the Commodore about 16l/100. We all know the Europeans post total BS to fool us into believing highly stressed small turbos have massively better economy than the NA engines they have replaced. They should be forced to put on figures for freeway, heavy traffic and performance.

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