WLTP has hit

Soldato
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Audi don't seem to show the WLTP values anyway, when you go through the configurator for a8/a4

they just seem to say
From 1st January 2019, energy efficiency labels displayed alongside vehicles in showrooms,

whereas , in 5s, look at a ford brochure and it's there in black and white
"The tables on pages 70 and 71 show the fuel consumption (WLTP) and CO2 emissions (NEDC equivalent) for each available engine when fitted on a standard specification All-New Ford Ford (with no options or accessories). Adding options or accessories to your chosen vehicle can impact WLTP fuel consumption and CO2 emissions. Please speak to your Ford dealer for more information. The fuel consumption you achieve in real life conditions and CO2 produced will depend upon a number of factors including any options and accessories fitted, variations in weather, driving styles and vehicle load."
 
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Thank you for the post, and also @Entai .

could it be that the truth is somewhere in the middle?

I know manufacturer's have to meet certain CO2 fleet figures, set by

If you tested the bookends only, it would regulatory be okay, but your fleet of sold cars would show a higher CO2 figure, which could potentially result in a fine. So testing the intermediates is beneficial, as it takes down the fleet CO2 figure which reduces your chances of a fine/the fine.

I work in the sector as well, albeit safety, so don't deal with emissions in depth. The above assumption is a combination of knowledge and educated guesswork. Feel free to correct/add.

Link: https://ec.europa.eu/clima/policies/transport/vehicles/cars_en
 
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Thank you for the post, and also @Entai .

could it be that the truth is somewhere in the middle?

I know manufacturer's have to meet certain CO2 fleet figures, set by

If you tested the bookends only, it would regulatory be okay, but your fleet of sold cars would show a higher CO2 figure, which could potentially result in a fine. So testing the intermediates is beneficial, as it takes down the fleet CO2 figure which reduces your chances of a fine/the fine.

I work in the sector as well, albeit safety, so don't deal with emissions in depth. The above assumption is a combination of knowledge and educated guesswork. Feel free to correct/add.

Link: https://ec.europa.eu/clima/policies/transport/vehicles/cars_en

So the bookends are tested purely so you basically have a Y = mx + c gradient interpolation for your car. So the Y axis is CO2, X axis are the bookend cars represented by their roadload (i.e. weight, aerodynamics properties and tyres, converted into an energy demand in Joules).

So when an individual car is built, the systems look up the level of Joules for the car based on all the options, then gives the car's individual CO2 value.

Car makers can choose to simplify it by just saying all their cars are at the top bookend and cover everything - but that'll obviously impact their CO2 fleet values.
 
Soldato
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It's truly amazing the passion with which you state something that is not only incorrect but impossible :p A single Type with just 20 options would have 1 million combinations to test. Clearly, obviously, all of those have not been tested yet vehicles with many more options than that are available with WLTP homologation.
WRONG they do not "calculate" anything.

Working for one of the UK labs doing the testing for a large number of OEM's I can tell you that without doubt manufacturers now HAVE to test;
  • all models in their range
  • and all possible engine configurations for all fuel types for each model
  • and all trim levels
  • and all options including all tyre and wheel combinations
No, the truth isn't in the middle: Entai doesn't get it and what DaveyD says is accurate.
Thank you for the post, and also @Entai .

could it be that the truth is somewhere in the middle?

I know manufacturer's have to meet certain CO2 fleet figures, set by

If you tested the bookends only, it would regulatory be okay, but your fleet of sold cars would show a higher CO2 figure, which could potentially result in a fine. So testing the intermediates is beneficial, as it takes down the fleet CO2 figure which reduces your chances of a fine/the fine.

I work in the sector as well, albeit safety, so don't deal with emissions in depth. The above assumption is a combination of knowledge and educated guesswork. Feel free to correct/add.

Link: https://ec.europa.eu/clima/policies/transport/vehicles/cars_en
 
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It's truly amazing the passion with which you state something that is not only incorrect but impossible :p A single Type with just 20 options would have 1 million combinations to test. Clearly, obviously, all of those have not been tested yet vehicles with many more options than that are available with WLTP homologation.

No, the truth isn't in the middle: Entai doesn't get it and what DaveyD says is accurate.

I was following this a bit last year on the TT forums and what seemed to be the conclusion was :

The combinations had to be tested of all models, all engines across each model, and all trim levels, this being the basic multiplication of variants (although some wouldn't exist, such as a diesel TTRS so that wouldn't be tested)
They also had to test the impact of each option/combination of options. so for example a tow bar that due to weight and wind resistance would typically add 1-2g/km would be consistent across all the engines etc of a model.

So it seemed to be that each option had to be tested on each model (but not each model and trim and engine combination), which would validate if the tow bar for example added 1g/km or 2g/km to an A1, an A3, a TT etc.
The trim level of a TT will not affect the impact of the tow bar, but the implications on aero may be different to an A1 for example, and of course a tow bar could be heavier or lighter from model to model.

What Entai actually wrote supports that position. They need to test every option, does not mean they need to test every possible combination of options., across every trim, across every model etc
No one seemed to be able to say specifically, but what one guy who was involved in testing said was they were doing "up to hundreds" of tests per model, and this was why some engines were not available etc at that time. Which would tally pretty well with all the engine and trim combos per model, and then testing each option combination for that model. Remember you only need to test options that affect weight or aero. Something like paint colour, wheel design (but not size), integrated bluetooth etc don't need testing.

The fact no one seemed to specifically be able to quote the requirements made people at the time and there still seems to be speculation that some of the requirements are open to interpretation, where as others are far clearer in their requirement to be tested. Eg adding leather seats (weight impact) and a tow bar (weigh and aero impact) may generate the same impact being tested individually and being added together as doing them both on one car. Simple maths may say however that if both had an individual impact of 0.7, rounding both to 1 means that 1+1=2 where as 0.7x2 = 1.4, rounded to 1 maybe? So its quite possible some of the "packs" of common items are also a lower impact when added as a pack than they would be added individually
 
Soldato
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Seat have been doing this since WLTP came in to affect. It actually made it so much easier to order a new car as I didn't have to look at a million options.
 
Soldato
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- still in history - The actual process/requirements were here p49 ... as said, a bounding/interpolation strategy.


https://www.unece.org/fileadmin/DAM/trans/doc/2015/wp29grpe/GRPE-72-02-Rev.1.pdf .. maybe there's a newer revision

4.4.1 Interpolation method One of the key objectives of WLTP, as specified in par. 4.2, is to develop the test cycle and test procedure in such a way that the resulting CO2 emission and fuel consumption is representative for real-life vehicle usage. One barrier to achieve that goal, which was identified early in the development process, is the fact that tests are executed on single vehicles while the results of these tests are used to type-approve a whole family of vehicles. The vehicles in one family would mainly differ from each other in terms of options selected by the customer that lead to differences in mass, tire/wheel rim combinations and vehicle body trim and/or shape. It was considered valuable to find a method that would attribute CO2 to individual vehicles within the family in an appropriate way. First of all, it was recognised that testing only one vehicle does not provide sufficient information. At least two different vehicles within the family have to be tested to determine a difference in CO2 that can be attributed to vehicle characteristics: one vehicle to the ‘worstcase’ side and preferably one to the ‘best-case’ side to allow good coverage of all vehicles in the family. Within the GTR these test vehicles are referred to as vehicle H and vehicle L respectively. It was also agreed that pollutant emission standards should be met by all vehicles within the family. The next challenge was to attribute the difference found in CO2 between vehicle H and L to vehicles in between. There is not a parameter available that single-handed correlates well to the increased CO2 as a result of differences in mass, aerodynamic drag and rolling resistance. As a first candidate, the mass of the vehicle was proposed as a parameter for interpolation between vehicle H and L. Analysis of such an interpolation method lead to unacceptable errors. This is easily understandable by considering that some options only add mass, while others (e.g. spoilers, wider tires) only have a marginal effect on mass but add considerable aerodynamic drag and/or rolling resistance. The final breakthrough in this discussion arrived with the insight that it is the energy needed at the wheels to follow the cycle which has a nearly direct effect on the CO2 of the test vehicle, under the assumption of a relatively constant engine efficiency for vehicle L and H. The cycle energy is the sum of the energy to overcome the total resistance of the vehicle, and the kinetic energy from acceleration

.

4.4.3 Interpolation/extrapolation range The accuracy of the interpolation method for CO2 has been validated by 2 vehicle manufacturers using their detailed in-house simulation models. The CO2 and Ecycle for vehicles L and H were determined, and used to interpolate the CO2 of vehicles in between. Comparing the interpolation results with the simulation results for intermediate vehicles of the family demonstrated that the interpolation method is accurate well within 1 g/km of CO2 up to a ∆CO2 of more than 30 g/km21. On the basis of these results the methodology was accepted and the allowed interpolation range was set to a maximum of 30 g/km or 20% of the CO2 for vehicle H, whichever is the lower value. The latter was needed to prevent that low CO2 emitting vehicles would receive a relatively large interpolation range. Also a lower range limit of 5 g/km between vehicle L and H was set to prevent that test-to-test measurement inaccuracies have a large influence on the course of the interpolation line. Finally it was also agreed that the interpolation line may be extrapolated to both ends by a maximum of 3 g/km, e.g. to include future vehicle modifications within the same type approval

I would still like to know why Audi don't have their values online like ford
 
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- still in history - The actual process/requirements were here p49 ... as said, a bounding/interpolation strategy.


https://www.unece.org/fileadmin/DAM/trans/doc/2015/wp29grpe/GRPE-72-02-Rev.1.pdf .. maybe there's a newer revision



I would still like to know why Audi don't have their values online like ford


Interesting, key bit bolded, which would again seem to bring it back to being an option to do the interpolation?

Vehicle selection Vehicle H is selected for the road load determination, being the vehicle within the CO2 vehicle family with the combination of road load relevant characteristics (i.e. mass, aerodynamic drag and tyre rolling resistance) producing the highest cycle energy demand (see also par. 4.4.2 of this report). If the manufacturer wants to apply the CO2 interpolation method, additionally the road load is also measured on vehicle L. This is the vehicle within the CO2 vehicle family with the combination of road load relevant characteristics (i.e. mass, aerodynamic drag and tyre rolling resistance) producing the lowest cycle energy demand.
 
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That's coming in 2020. It's going to cause havoc with availability of certain models, and will massively increase sales of BEVs and PHEVs.
Pretty sure it’s already in place. Link i posted has more details.

Link seems to say since 2015, with stricter targets coming in 2021.
 
Soldato
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They do not need to test each option on each model. The relationship between options and changes is not simple and additive e.g. if a towbar adds 2g/km and a sunroof 1g/km to a Audi A6 2.0 TDI, a towbar and a sunroof don't necessarily add 3/gkm in total on that A6, and neither does a towbar necessarily add 2/gkm to an A6 3.0 TDI. A towbar could add 1/gkm to an A6 3.0 TDI S line but 2/gkm to an A6 3.0 TDI SE. This is because there are various equipment that will not independently trigger some underlying engineering change, but will together e.g. you can have a towbar or a sunroof independently, but have them together and they need to fit a heavier battery. This sort of change is transparent to the buyer but is very common as equipment is loaded on to a car by trim lines, packages or options. Once you understand that, it becomes very clear that testing each equipment is not feasible hence why the interpolation system was drawn up for WLTP. Moreover, manufacturers change parts suppliers all the time, and make product and engineering changes regularly. They are not going to send a new car for testing because they switched to a supplier with a sightly heavier part, or send another car because they now wanted to fit leather seats as standard. Manufacturers can choose to make all sorts of additional tests for their own research and development and validation purposes but they are simply not required to test every option.
I was following this a bit last year on the TT forums and what seemed to be the conclusion was :

The combinations had to be tested of all models, all engines across each model, and all trim levels, this being the basic multiplication of variants (although some wouldn't exist, such as a diesel TTRS so that wouldn't be tested)
They also had to test the impact of each option/combination of options. so for example a tow bar that due to weight and wind resistance would typically add 1-2g/km would be consistent across all the engines etc of a model.

So it seemed to be that each option had to be tested on each model (but not each model and trim and engine combination), which would validate if the tow bar for example added 1g/km or 2g/km to an A1, an A3, a TT etc.
The trim level of a TT will not affect the impact of the tow bar, but the implications on aero may be different to an A1 for example, and of course a tow bar could be heavier or lighter from model to model.

What Entai actually wrote supports that position. They need to test every option, does not mean they need to test every possible combination of options., across every trim, across every model etc
No one seemed to be able to say specifically, but what one guy who was involved in testing said was they were doing "up to hundreds" of tests per model, and this was why some engines were not available etc at that time. Which would tally pretty well with all the engine and trim combos per model, and then testing each option combination for that model. Remember you only need to test options that affect weight or aero. Something like paint colour, wheel design (but not size), integrated bluetooth etc don't need testing.
For the purposes of WLTP it makes no difference if three options are added as a package or three options are individually added. It is exactly the same calculation. What happens in your example is that the car with towbar has +0.7g/km, car with leather has +0.7g/km, and a car with both has a figure calculation for a car with both. This could be +1.4g/km or it could be +1.2g/km.
The fact no one seemed to specifically be able to quote the requirements made people at the time and there still seems to be speculation that some of the requirements are open to interpretation, where as others are far clearer in their requirement to be tested. Eg adding leather seats (weight impact) and a tow bar (weigh and aero impact) may generate the same impact being tested individually and being added together as doing them both on one car. Simple maths may say however that if both had an individual impact of 0.7, rounding both to 1 means that 1+1=2 where as 0.7x2 = 1.4, rounded to 1 maybe? So its quite possible some of the "packs" of common items are also a lower impact when added as a pack than they would be added individually
 
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Man of Honour
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- still in history - The actual process/requirements were here p49 ... as said, a bounding/interpolation strategy.


https://www.unece.org/fileadmin/DAM/trans/doc/2015/wp29grpe/GRPE-72-02-Rev.1.pdf .. maybe there's a newer revision



I would still like to know why Audi don't have their values online like ford

In UK, it doesn’t need to be stated - it’s not very consistent across the industry - NEDC is still the basis of taxation in UK for at least next year until the government figure out how to do new tax baes on WLTP. All their new cars now will be WLTP compliant and tested, just you’d have to ask your dealer to tell you what they were - most still don’t actually understand it though from my experience.

If you wanted to find out a rough WLTP number for an equivalent Audi, their German site will give their CO2 in back-end configurator as they are taxed by CO2 for WLTP. Places like Finland already show WLTP figures only, so eventually we will get the same.
 
Soldato
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Pretty sure it’s already in place. Link i posted has more details.

Link seems to say since 2015, with stricter targets coming in 2021.

The 2015 limit was for the EU-wide fleet, not by manufacturer. From 2020 manufacturer by manufacturer limits kick in. The link you posted has more details.
 
Soldato
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the links interesting, suggesting that new registrations are currently averaging 5.6l/100km that's 50mpg , already met in 2013 - really ? or that is pre-VW.

Since 2015, a target of 130 grams of CO2 per kilometre applies for the EU fleet-wide average emission of new passenger cars.

Emissions of 130 g CO2/km correspond to a fuel consumption of around 5.6 litres per 100 km (l/100 km) of petrol or 4.9 l/100 km of diesel.

This EU fleet-wide target was already reached in 2013, two years ahead of schedule.

it also (contradictingly?) talks about existing manufacturer specific penalty premiums ... so do we know which are the better/worse manufacturers (need to do some googling)
If the average CO2 emissions of a manufacturer's fleet exceed its target in a given year, the manufacturer has to pay an excess emissions premium for each car registered.

Until 2018, this premium amounts to

  • €5 for the first g/km of exceedance
  • €15 for the second g/km
  • €25 for the third g/km
  • €95 for each subsequent g/km.
 
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@PMKeates

Well all I know is i have just spent the last nearly 14 months doing 1357 tests (so far) purely on the Jaguar range of vehicles and their various options, and there are still a good 4 to 5 months of testing left.

I highly doubt a manufacturer like Jaguar would do that and spend several million on testing so far if they could just calculate the results.
 
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The 2015 limit was for the EU-wide fleet, not by manufacturer. From 2020 manufacturer by manufacturer limits kick in. The link you posted has more details.

Manufacturers have limits set to achieve the EU wide targets. The link i posted indeed has the details.
 
Soldato
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Had subsequently looked at jaguar xe model some 20 engine/transmission options https://www.honestjohn.co.uk/carbycar/jaguar/xe-2015/data/
if you throw in bookend/bounding H/L wheel sizes and exterior trim packages, maybe multiply by 2x3=6 so 120 executions of the WLTP driving squence with full data-logging.

with 10 models you are then, already in the 1000's, without testing all combinations of mass the vehicle might have, which is where you would interpolate.
 
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