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Comment by emp_zealoth | Hacker News Reader

Or maybe we abolish nonsensical, contrary requirements?

Whoever actaully believed the fuel consumption figures is a fool. You cant have a 1,5t of a car and expect it to use only 5l/100km. That's a good rate for a goddamn motorbike (450ccm,one piston, dont exceed 90 km/h and you might reach 4,5l/100km) Its one fifth of the mass...

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Well sorry for being a fool then. It's impossible to investigate everything about every part of our lives, and personally I feel a bit cheated by these revelations.

I think most people are aware there could be cheating, but not on the scale being claimed. I don't think it's unreasonable to have placed a bit of trust in the number.

that's no excuse, its basically ignorance. not personal critique, but still lots of people follow blindly things they don't understand.

Of course they do. People have limited time and energy and can't possibly be expected to have a good enough understanding of everything they touch in their daily lives to be able to "understand" them well enough to have sufficiently calibrated bullshit detectors for them all.

Maybe you're an expert in ICEs and this was obvious to you. Would you notice if your cell phone charger was actually pulling 10 amps out of the wall instead of the 1 it was rated for? What about if your non-GMO strawberries were actually created in a lab? Your organic beef injected with hormones?

The whole point of having these standards is so that consumers can rely on them and don't have to independently analyze everything they buy themselves.

They didn't call those bands "rage against the machine" and "public enemy" for nuthin now did they? I mean, in all seriousness, why be so serious? Simple points need to be understood, not simply dismissed out of hand. In theory everything the government or your employer tells you is true. In reality, they have alot to gain from asymetric information distribution, both in terms of negotiating financial outcomes but also in terms of maintaining their political power base.

Have you checked your keyboard's electrical path for surveillance equipment this morning?

Did you test your water for drugs this morning?

Did you check them yesterday?

We all live at certain layers of abstraction.

Have you ever measured a 2x4?

probably not

All you have to do is look at how much gas you put in the damn thing and divide by how much youve driven since you last topped up. Not a deep investigative effort

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That's like saying someone threw a rock at you and because you didn't look around before it hit you, its your fault. The cheating is the problem, not the fact that people are ignorant about it.

no, its like saying "caveat emptor"

http://rockyroadblog.com/caveat-emptor-vetting-mpg-claims-30...

Sorry, that BS. Nobody wants to conduct a research experiment every-time they purchase splenda to see if it might give them cancer in 10 years. It is impossible to live life that way. Social guarantees that your water supply does not contain poison, and that the car you purchase doesn't not fall apart and kill you at 45 mph when it worked fine at 20mph when you did the test drive, are and should be expected. Just because cheating is widespread does not make it your fault for not knowing it.

nobody wants to read website TOS either, but that's not how the world or the law work. there is a line between 'street smarts' and blind faith in people you don't know telling you stuff. 2x4's are not 2x4...that's something everyone probably should know...similarly, EPA fuel mileage is not accurate...and never has been...its not anyone's fault that everything in the world is not "literally" true

The same transaction costs argument for regulatory disclosure apply to the quality of such disclosure as well. Ever try reading nutritional labels? It goes on and on...has very little to do with one particular instance.

That being said, a auto is a capital good and a substantial purchase and investing some time to understand the buying process is both economic and sensible. so in this case the faux shock/outrage seems particularly misplaced...as the arguments for ignorance are weak indeed.

I actually drove my Golf TDI at around the level of 5l/100km in Berlin for many years. Carefully. My girlfriend's Polo is significantly below that. Of course, these cars aren't ton and a half, but more around a ton.

Yup. Diesel cars can pull of 5l/100km quite easily (even VW Passat from 1998 can do that). My diesel Skoda Fabia consumes 4.6l/100km at 90kmh in highway. If conditions are not terrible, I hover around 5l/100km on average in mixed conditions (city and highway). Though few major traffic jams can ruin statistics pretty badly. Also in winter average is about 5.6l/100km.

Maybe /user/emp_zealoth had petrol cars in mind? I've not personally seen a petrol (non hybrid) car consuming less than 7l/100km and when I had one it was 10l/100km (8 if I was lucky) and it was small Peugeot 306.

To rant even more.. IMHO, those fuel consumption tests are a total fraud. Look at new diesel sedans, local dealer declares that huge VW Passat TDI uses 4l/100km, or Skoda Octavia TDI (GreenLine or something) uses 3.1l/100km. Maybe it's true when you're driving at 90km/h with wind blowing in your tail and slight downhill.

You forgot the bicycle tires. :-)

Yes, i was talking about gasoline ones, diesels can and do get lower fuel consumption

I've got an 2016 Audi A4.

Audi claims 22mpg city, 32mpg highway and 26mpg combined.

What I see is 24mpg city, 31mpg highway and 26mpg combined; I don't drive especially slow either. FWIW, I factory ordered a manual transmission so that may make a difference.

I'm skeptical of cars that claim crazy high MPG ratings and performance cars claiming good MPG numbers, but for a standard car I do expect the numbers to be achievable. I've gone through a lot of cars over the years and I've gotten very close to the published numbers on all but one (Cadillac CTS).

Those numbers (37.2 miles per imperial gallon) are in the 3.0 TDI territory for Audi in the British(/EU?) market. Many would be disappointed with 37.2 highway for any 2.0 diesel engine: look at the 'Real MPG Avg' column at http://www.honestjohn.co.uk/realmpg/audi/a4-b8-2008

I don't think they're especially good or bad, my point was just that they are almost exactly what Audi claimed.

After the VW news I'm rather happy I went with petrol. Actually I never gave diesel a thought because Audi doesn't sell A3 or A4 diesels in the US (at least dealers don't have them and the website doesn't show them).

(You need to specify whether you're US or UK. Different gallon sizes! It makes US MPG ratings seem significantly worse than UK ones.)

And those darn Europeans measure it in liters-per-100-kilometer, just to make it worse!

Yeah, I always forget about that. I'm in the US so I'm allowed to forget about the rest of the world, right?

Your comparison with motorcycles is a bit flawed. Weight is the wrong thing to look at; at highway speeds drag is a major factor and motorcycles actually have higher drag coefficients than cars. You're also understating motorcycle fuel economy: I can easily get 4.5L/100km on my 600cc I4 doing 100km/h (although I more typically drive 130km/h and get 5L/100). I have friends who regularly do < 4L/100km in practice (on a 250, though).

My Chevrolet Sonic (with a 1.4L turbocharged gasoline engine and a curb weight of around 1.4 US tons or 1.5 metric tons) gets 42-ish MPG (5.6 L/100 km) during the summer and my driving conditions aren't even ideal (half my commute is highway speeds with stoplights). A Toyota Prius (Auris) could probably get more than 50 MPG (less than 4.7 L/100 km) on the same route.

A larger part of fuel consumption is driving behavior. My Ford Fusion (non-hybrid) only gets about 15 mpg in city/rush-hour driving because I drive very aggressively...but nearly 40 mpg on the freeway using cruise control (set to 75-80mph).

Comparing to known fuel effiencies of existing vehicles competely misses the point, which is to stimulate new technology development. For example, aluminum and plastic car body pieces, which reduce weight.

If you want to talk about "believable," start from basic physics and calculate the best possible fuel efficiency that a car could be expected to deliver. Even taking into account available materials, fuels, and engines, the answer is way better than what regulations currently require.

A lot of the expected gains will come from taking known "custom" solutions and scaling them up to mass market--like greater use of aluminum, and ultimately, composites.

> You cant have a 1,5t of a car and expect it to use only 5l/100km

So you are telling me that my actual, measured fuel consumption numbers of 4.25l/100km on flat highways in the US South are impossible? I have a diesel Passat (yes, one of the NOx Boxes :P) and can get from Dallas, TX to Pensacola, FL (650 mi) without refueling and with a decent reserve (~2 gallons) still in the tank.

The thing is that this report does actually not provide any data about fuel consumption - only about CO2 emissions.

What they do is wild speculation and possibly a smear campaign because people care more about the fuel economy (their own money) than CO2 emissions.

It is interesting that this (some) data is provided but how it is presented does not make it look very credible.

What are you on about? For any given type of fuel, fuel consumption is related exactly 1:1 proportionately to CO2 emission (as carbon particulate and CO emissions are microscopically small these days). That is basic chemistry - where else would the fuel go?

Therefore any claim about CO2 emissions equates to a claim about fuel consumption.

Yes, it should be.

The problem is that these findings do not reflect my anecdotal experience.

I have two recent measurements. About 500 km round trip and small trips inside the city.

This is accordingly about 17% and 21% increase (and it was in the same region for the older model of the same car).

Sorry, I did not include the make and model of the car because I do not want to leak too much personal information but it is nowhere close to the claimed difference.

Even more the round trip was mostly on the highway and included small city part (let say about 20 km). This differs from the official test cycle.

Also the city traffic includes high elevation differences and very bad slow traffic with constant stopping.

Also the car was more occupied in both cases (official tests consider about 70 kg driver and 7 kg luggage).

This means that in more fair test the results should be even more close to the official numbers.

So what could explain this?

I do not know as we do not see the fuel economy numbers.

Perhaps during the official tests the car is actually stationary and can not take enough air and the burning is not that efficient but a good exhaust filter hides this problem?

What is also strange is the difference between BMW 3rd series and 5th series because both use the same engines (and also some Renault models do use BMW engines but it do not know about Megane).

I calculated the fuel consumption and CO2 ratio for several models and it is about the same (as expected).

I also calculated weight to CO2 ratio for similar engines over few series and this gave also very similar results. As the different series look quite similar these days then I would assume that they also have quite similar aerodynamics.

After carefully reading again what they stating stating, it appears that even when they talk about CO2 emissions, they actually base their claims on self reported fuel consumption data from http://www.spritmonitor.de

It looks to me that the following is entered (I have not used the app) by the users.

Objective data:

  Date of fuelling,
  Current odometer value,
  Amount and price of fuel.
  Type of tires (summer/winter) [should be mostly objective]

Subjective data:

  Driving style used (Moderate, Normal, Fast),
  Roads driven (Motor-way, City, Country roads)

For roads driven all the options could be selected and are then doubly reported in the detailed statistics.

This means that there is no objective acceleration and speed profile and also elevation difference data is missing (is not collected).

To illustrate this I will compare two different entries for BMW 3er 320d touring efficient dynamic

1) http://www.spritmonitor.de/en/detail/595885.html?cdetail=1 (2012, 120 kW, 4,14 l/100km) 2) http://www.spritmonitor.de/en/detail/672858.html?cdetail=1 (2011, 120 kW, 5,54 l/100km)

As both cars have the same power, I assume that they are the same model.

The consumption difference is 33%!

Driver one believes that driving style has been mostly moderate and driver two believes that driving style has mostly been normal.

Edit: I think that it illustrates that it is possible to drive this car close to its spec but it also easy to have more courageous driving style.

In addition to what MagnumOpus said, CO2 emissions are irrelevant. I was calling them on a particular statement they made that I found to be ridiculous.

The requirement was to incentivise more efficient cars. Manufacturers just decided to ignore the requirement and lie about it instead. Customers decided to believe them.

Cars keep getting bigger and heavier. The current Golf -- nominally a compact car -- is half a meter longer (at least 4.25m) than the first one and half a ton heavier (at least 1.2t).

It's achievable with a diesel and not too-heavy foot easily (possibly with some extra NOx ;-)

Your numbers are also false for motorcycles (which all run on gas and not diesel which is the subject of the conversation here). My BMW's 800cc rotax paralell twin does exactly that (4.5L cruising on the highway). Even the 1200cc boxer does that AFAIK.

My 2013 Qashqai 1.6dCi 4x4 weighs exactly 1630kg and uses between 5-6 litres of diesel for every 100km traveled, depending how aggressively I drive it. And no, that's not the value from the car's computer, that's an actual usage.

Just one bit of evidence to the contrary. I have filled the 70 litre tank in a 1.6tdi VW Passat and driven 1400 km with 5 occupants and luggage. This was mainly European motorway driving.

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