[VeyronSuperSprt]

Mercedes-Benz topped a European lobbying group’s list of carmakers to overstate fuel economy for the second year in a row in an annual study that may receive extra scrutiny amid Volkswagen AG’s diesel-engine test scandal.

Vehicles built by Daimler AG’s Mercedes division used 48 percent more fuel on average than their published statistics claim, with gaps exceeding 50 percent on new A-, C- and E-Class models, Brussels-based Transport & Environment said Monday. BMW’s 5-Series and the Peugeot 308 produced differences between real-world and laboratory results of just under 50 percent. Across the industry, the gap widened to 40 percent last year from 8 percent in 2001, with the difference between published specifications and actual fuel use costing a typical driver an additional 450 euros ($500) yearly at the pump.

T&E based its figures on a 600,000-car analysis compiled by the nonprofit International Council on Clean Transportation. Another ICCT analysis, in 2013, prompted the U.S. probe that resulted in Volkswagen’s admission that it installed software to cheat on diesel emissions tests in some 11 million vehicles.

http://www.bloomberg.com/news/articl...g-fuel-economy

[y448]

How can a company get away with this? people will get to know the real mileage and complain about low mileage during service visits rt? May be Europeans are not mileage obsessed as we Indians are but still real world mileage should become known to the potential buyers from the initial adopters of the vehicles.

In India if a car company advertises 30kmpl and real world mileage is less than 15 kmpl then this will provide counter productive for them as three would be lot of displeased customers in their service centers and will bring bad reputation to the company also.

[TMRT]

This whole VW episode has made me skeptical of the numbers reported by Dashboard panels. Hard to believe Jetta would give out 28kmpl

http://www.team-bhp.com/forum/indian...ml#post3813534

[alpha1]

Originally Posted by VeyronSuperSprt

Vehicles built by Daimler AG’s Mercedes division used 48 percent more fuel on average than their published statistics claim, with gaps exceeding 50 percent on new A-, C- and E-Class models, Brussels-based Transport & Environment said Monday. BMW’s 5-Series and the Peugeot 308 produced differences between real-world and laboratory results of just under 50 percent. Across the industry, the gap widened to 40 percent last year from 8 percent in 2001, with the difference between published specifications and actual fuel use costing a typical driver an additional 450 euros ($500) yearly at the pump.

What is disputable (and therefore requires more details) here is how is the laboratory test done and how are "real world" tests done?

Unless we know the details it would be imprudent to pronounce a judgement or even form an opinion.

[iamahunter]

Originally Posted by TMRT

This whole VW episode has made me skeptical of the numbers reported by Dashboard panels. Hard to believe Jetta would give out 28kmpl

http://www.team-bhp.com/forum/indian...ml#post3813534

The figures shown on the mid are rarely correct. They are usually higher than the real ones.
I've noticed this on many cars from other manufactures as well.

If you want to know the "REAL" average of your car, just try tank full to tank full method.

You may also use a fuel management apps available on app store.
There are many.

[GTO]

I don't understand what's the news in this. It's an accepted fact that official fuel economy figures are calculated 'under ideal test conditions'.

How many Hero Honda bikes give 100 kpl in real life? Our very own ARAI certifies cars for 25 kpl. How many of them match it?

The article says that in 2001, the difference between claimed & real world numbers was slimmer. That's probably down to the addition of gears. 7 & 8 ratio gearboxes are commonplace today. These make a difference on the highway only (not in the city where they are rarely engaged) and - I have a feeling - help the 'ideal test conditions' numbers too.

[arnabchak]

Originally Posted by GTO

I don't understand what's the news in this. It's an accepted fact that official fuel economy figures are calculated 'under ideal test conditions'.

How many Hero Honda bikes give 100 kpl in real life? Our very own ARAI certifies cars for 25 kpl. How many of them match it?

The article says that in 2001, the difference between claimed & real world numbers was slimmer. That's probably down to the addition of gears. 7 & 8 ratio gearboxes are commonplace today. These make a difference on the highway only (not in the city where they are rarely engaged) and - I have a feeling - help the 'ideal test conditions' numbers too.

Absolutely spot on Rush.

Remember one of the earier ads of a super flop bike- TVS Centra.
One of its biggest reasons for the downfall inspite of it using the Victor engine bits was its tall 100 kmpl claim.

Real time FE was a good 60-65 kmpl but the general "junta" dismissed the bike saying it is "achcha average wala bike nahin hain".

It is common place to inflate the FE and Maruti takes top honour for this. Ciaz is a 28.5 kmpl car with teh hybrid and come 2016, Dzire may take teh mantle for a 30+ kmpl.

Can these be achievable? Not in real time But yes, on highways, the FE can significantly take an upward swing.

[VeyronSuperSprt]

Fuel efficiency calculations abroad are based on Urban, Extra Urban and Combined fuel consumption figures. The way these tests have to be conducted are also defined and are unlike the ideal test conditions as carried out by the ARAI which reflect just the maximum fuel efficiency.

For reference here's how they are supposed to arrive at the Urban, Extra Urban and Combined consumption figures:

Urban Cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).

Extra-Urban Cycle
This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).

Combined Fuel Consumption Figure
The combined figure presented is for the urban and extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.

The 3 cycles together should give a more accurate reflection than just one figure of an ideal test condition and shouldn't give a variation of more than 50%.

[StarrySky]

Originally Posted by GTO

I don't understand what's the news in this. It's an accepted fact that official fuel economy figures are calculated 'under ideal test conditions'.

Overstating the fuel efficiency values also means that the manufacturer is underestimating the CO2 emissions of the car. In Europe, car/road tax in many countries is linked to CO2 emissions. Lower CO2 emissions means lower tax and consequently lower cost of ownership for the customer. So there is an advantage in overestimating FE figures. In the real-world, owners won't mind a small drop in FE compared to the stated figures. But, from a regulator's point of view, that small drop may be enough to push the car to a higher tax bracket.

[mayankk]

Well, these are assorted ARAI figures.
Who has hit the claimed figures? Im aware of a fraction of the cars on the list, driven or know of, and none of them ever gave these figures out of the factory, or even after the first service.
This will not impact mercedes as much as what VW is going to face for its acts.

[sgiitk]

Originally Posted by GTO

How many Hero Honda bikes give 100 kpl in real life? Our very own ARAI certifies cars for 25 kpl. How many of them match it?

The article says that in 2001, the difference between claimed & real world numbers was slimmer. That's probably down to the addition of gears. 7 & 8 ratio gearboxes are commonplace today. These make a difference on the highway only (not in the city where they are rarely engaged) and - I have a feeling - help the 'ideal test conditions' numbers too.

In reality one can find some use in using the official figures s rough guide, nothing more. This is esp true when comparing similar cars! With performance cars a lot may depend on how heavy are your lead boots!!

[alpha1]

Originally Posted by VeyronSuperSprt

Urban Cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).

Extra-Urban Cycle
This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).

.

So is there a grouse that such test figures are not matching what is experienced in real life driving a Mercedes?

But then they clearly say that the reasons are:

1. Increasingly exploiting loopholes and flexibility in the testing procedure including “cycle beating” techniques to unfairly reduce emissions during a test [Let us not call it "exploiting the loopholes", they are functioning within the realm of govt imposed publicly loved "regulations"]
2. Deploying technology on cars that has benefits principally in the test but not on the road [business is not done for altruistic reasons]
3. Fitting increasing amounts of equipment to cars that is switched off during the test – such as air conditioning [i don't see any issue here unless the regulation clearly states that all electrical/mechanical devices in the vehicle shall be switched on during the test but the manufacturers don't]

[VeyronSuperSprt]

Originally Posted by alpha1

2. Deploying technology on cars that has benefits principally in the test but not on the road [business is not done for altruistic reasons]

Couldn't have stated that better.

Now all that remains is for VW lawyers to state that as the reason for their 11 million car fiasco and they'll be allowed to go scot free.

[ghodlur]

Originally Posted by GTO

I don't understand what's the news in this. It's an accepted fact that official fuel economy figures are calculated 'under ideal test conditions'.

Agreed GTO that the mileage quoted are in ideal test conditions but a difference between the ideal and the actual mileage achieved should not be more than 10-20%. Here the difference is almost close to 50% which means that the manufacturer is not transparent enough to disclose the actual mileage that can be achieved.

Back home ARAI figures for Fiat Punto was 20 kmpl as per the brochure for the 1.3 MJD 75 HP. I am getting close to 21 kmpl during every refill and if I try to match the ideal driving conditions I will definitely get more.

[arnabchak]

Originally Posted by ghodlur

Agreed GTO that the mileage quoted are in ideal test conditions but a difference between the ideal and the actual mileage achieved should not be more than 10-20%. Here the difference is almost close to 50% which means that the manufacturer is not transparent enough to disclose the actual mileage that can be achieved.

Back home ARAI figures for Fiat Punto was 20 kmpl as per the brochure for the 1.3 MJD 75 HP. I am getting close to 21 kmpl during every refill and if I try to match the ideal driving conditions I will definitely get more.

I too achieve mileage figures more than the claimed 26.5 km/kg of CNG in the Wagon R.

In various highway trips, FE close to 33 km/kg has been achieved a number of times.

Of my recent trips, the FE recorded in the Goa tour was 270 kms in 7.9 kgs of gas= 34.2 kms/kg. This is nothing sort of phenomenal.

Agree that there may be slight variance compared to petrol/diesel tank to tank method vs the 200 psi for CNG.

Even if I give the leeway and assume that the CNG was max. tank full of approx. of approx. 8.5 kgs, still the FE is close to 32 km/kg and more than the ARAI for 26.5 for the waggie.