Study: Some car models consuming around 50% more fuel than official results
transportenvironment.org
transportenvironment.org
A reckoning is coming.
source: see page 13, here
http://www.transportenvironment.org/sites/te/files/publicati...
Bizarrely the NEDC procedure allows carmakers to actually declare (use) a value 4% lower than the one measured. The provision is designed to minimize the testing burden but is being abused by carmakers to declare lower test results systematically."
I wonder if there is a person that didn't expect this to happen.
This is going to sound backwards, but consider this: People buy cars based in part on MpG, however MpG is within itself an abstract thing (i.e. you don't actually get X miles per gallon, never did, never will too many other factors to include).
So if everyone removes 4% from an abstract number, the entire market has shifted down, but the relative difference between two models remains identical (e.g. if one car has 21 MpG and another has 25 MpG, even with 4% removed from both they retain their relative position).
If some were removing 4% while others weren't, that would legitimately be a problem. If they're all removing 4% then we're essentially where we would be at the start just with lower abstract numbers.
Presumably not everyone cheated the same, as well.
- We base regulations and taxes on absolute MpG, so overstating efficiency weakens the regulations and allows automakers to cheat on taxes.
- It misleads consumers about the cost to operate the vehicle.
- It is an issue when comparing efficiency of new cars to older cars produced before the systemic cheating.
This wouldn't be hard to fix.
Loan cars to a random selection of non-professional beta drivers. Graph the results, showing the median and sd.
It would be cheaper to do this than to get hit by a class action for misleading buyers.
Of course reality-based non-expert mpg would look very bad compared to the dishonest figures you get now. But that's because of manufacturing and design decision, and not really the fault of the drivers.
>Mercedes cars have the biggest average gap between test and real-world performance, with real-world fuel consumption exceeding test results by nearly half.
Edit: Apparently I am wrong.
You first misread my comment, and now you're misreading the chart, apparently, so let me explain: the chart I cited shows the percentage of claimed improvement in fuel economy which was actually delivered in real-world driving.
This is precisely what my comment said.
Edit: I think your confusion might lie in the math that you think is being done, perhaps? The chart is showing the DIFFERENCE between two numbers. It's not based on just the claimed improvement. It's the actual improvement divided by the claim.
GM made a claim of improvement and their performance actually went down, so their number is around -38%. Daimler was the next-worst at around 16%.
Is this the best, or a reliable source, of information to start the reckoning/witch hunt to come? I'm not sure.
My dad taught me lots of tips on conserving fuel and thankfully I've exceeded the sticker numbers on every car I've owned.
- 135 km/h 7.8l/100km (30 mpg)
- 125 km/h 6.5l/100km (36 mpg)
- 115 km/h 5.4l/100km (43 mpg)
I never realised speed made such a difference!
(Mpg is US gallons)
source: presentation by Dr. Rizzoni at Center for Automotive Research at OSU
Aerodynamic drag i.e. force opposite the direction of travel is proportional to the square of your velocity. Power consumption for steady cruising is equal to drag multiplied by speed. Thus power consumption is proportional to the cube of speed.
- 84.0 mph
- 77.5 mph
- 71.5 mph
For us in the states.
It gets exponentially harder to push air out of the way the higher the speed gets.
- When accelerating, try not to over-extend the throttle. If the engine is at 2k rpm, you get just as much acceleration from 30% throttle as 100%, at half the fuel cost.
- Release the throttle well before you reach a traffic light/stop sign. Deceleration by engine will cause a smoother stop and gives the traffic light more time to turn green. You spend less fuel trying to reach the stop line, and spend less fuel accelerating again. Bonus points for shifting down while decelerating.
- Keep tires well-inflated and oil levels up. Less friction means less wasted energy on both.
- Choose the highest gear when cruising. Most cars since 1990 can do 50kmh (30mph) even in fifth gear, as long as you don't need to accelerate.
- Drive slower. Most car engines are most efficient around 3500 rpm, which maps to somewhere between 90-110 kmh (60-70mph). Most highways allow for a higher speed. Diesel engines have their optimum at 2000 rpm, or so I've been told.
Of course most of this works best with a stick shift. I've never driven an automatic.
You can do this for automatics too - you just have to learn where the shift points are and drive at the right speed. Lift up on the accelerator quickly to upshift, press it down quickly to downshift. One thing that I notice easily when riding is when the driver is constantly staying at only a few km/h slower than the shift point, causing the engine to spin faster and consume more fuel than necessary. It often means the car is louder and vibrates more too, so not a good thing overall.
This is harder to do for newer models with quieter engines and smoother shifts but older automatics have very noticeable shifts and engine noise to judge whether you're near the bottom or top of each gear. It's very noticeable in larger trucks and buses.
Edit: another point I'll add to the list is traffic light phasing - look far ahead and observe the timing of the lights, and adjust your speed so that you're not going too fast (you'll arrive at a light before it turns green) or too slow (it'll turn red very shortly before you arrive). Obviously, you should do this only if traffic permits, but it's a great "trick" (not so much a weird one) when you can get from your origin to your destination at a constant speed with nearly no stops.
At least some manuals with EFI also have power governing to protect the transmission.
Is it a actual Continuously Variable Transmission (CVT) or an automatic transmission? There's nothing 'smart' in a CVT since there's gears to shift between, and it's highly unlikely you're going to do 'better' under normal driving since the point of a CVT is to allow the engine to run at ideal RPM's no matter the speed.
CVT has some inefficiencies that can be improved by putting the gear selection process from an automatic onto a manual (with an automated sequential manual gearbox or a "double-clutch" transmission).
Well, that's obviously not true.
edit: downvoters are once again proving that HN doesn't get jokes.
Have you tried being funnier?
Also, from the guidelines:
Please resist commenting about being downvoted. It never does any good, and it makes boring reading.
Now, mountains are another story, of course.
Some good stuff in this SE question: http://physics.stackexchange.com/questions/6220/can-a-car-ge...
This is physically impossible. Even if the car was perfectly efficient at overcoming the force of gravity on the uphill portions (which it is not), you cannot do better than flat terrain (unless by hilly you mean 'net downhill').
But the actual situation has two novel features: (1) the engine uses up power just by being on; (2) you must maintain a minimum speed in order not to block traffic.
If you put these constraints in, you can see that it's possible for a pulsed-acceleration strategy to win. You put in a pulse of acceleration to get up the hill, turn the engine off, and coast down, maintaining enough speed to keep up with traffic.
Now sure, without the minimum-speed constraint, you'd probably be better off flat, and possibly using a pulsed-acceleration strategy.
I haven't done the math, but I think it would be reckless to say it's "physically impossible" for all values of static energy use and slopes.
Take a look at the stack exchange answer the commenter above linked to.
But you raise good points, maybe I jumped the gun on 'physically impossible'.
Even if you do downshift that doesn't necessarily mean you're being less efficient either. Being a bit higher up the rev range may actually put you in a better spot on the efficiency curve for a given power output.
http://ecomodder.com/wiki/index.php/Brake_Specific_Fuel_Cons...
I've also observed the effect that the OP mentioned: in my Honda Fit, I get a fairly consistent ~45 MPG on 101 (completely flat highway terrain), ~40 MPG on 280 (rolling hills, highway), and ~43 MPG on 84 (across the Santa Cruz Mountains; ascends 3000 ft. in a series of tight switchbacks and then descends 3000 ft. in a wavy line). My working hypothesis is that the descent on 84 is consistent enough that the engine computer can idle the engine for all of it, burning no fuel - this is consistent with the car being nearly silent on the downhill, and of the instantaneous mileage display being stuck at its max of 80 MPG. Probably also helps that speeds are much lower, so there's less air resistance.
Anyway, the point is that cars are complex enough that the simple models you learn in Physics 101 don't really hold.
It's known that you can get better fuel economy by oscillating speed on flat ground - using WOT to gain speed, coasting back down, opening up WOT again. This is because the engine is most efficient under load and the average consumption works out better. Adding in the hills would average this effect.
An engine operating at WOT but still producing a fraction of its maximum output is certainly possible (and generally more efficient than an engine producing the same output at a partial throttle setting). A diesel engine is almost always in this configuration (metering fuel but generally not restricting air with a throttle plate) and a gas engine at low RPM but WOT is also in this state.
If tuned for efficiency in that config, it can be very efficient and is how many piston airplane engines are regularly operated where fuel consumption is an important part of range (and operating economics).
I actually observed this and it is true in my case; I do get better mileage when choosing a route through a canyon than when using regular freeway.
I suspect though that the real reason is that it basically affects how I'm driving. When I ride in a canyon I can't accelerate much because there are constant turns, while on straight freeway I most likely will accelerate.
This also would explain why most of the time I get better mileage in traffic (the EV is used most of the time).
There are scenarios where it's true, but there are a lot of factors involved (drag, power/efficiency curves of the engine, etc..., net-negative displacement, etc...)
Obviously aerodynamics play a part, however the cyclist's 'engine is cut' on the downhill and on big cross country roads no brakes need be used on the descents. When the 'engine' is on it goes at a certain not-quite-racing amount whether up hill or on the flat. But place a hill in the way of A to B and vastly more 'fuel' is used than A to B 'going the flat way'.
What if you can start by coasting 90% of the distance with zero expenditure of energy? What if it was 95%? Now assume that your chain is extremely rusty (low efficiency drivetrain). Would it be possible that the energy to go the short distance up the remaining hill (after coasting downhill and halfway up the other side) might be less than overcoming the friction of pedaling the whole way?
I'm not certain that they occur on a bicycle in the real world (perhaps you need a custom crafted rusty chain that has essentially constant high losses regardless of pedaling speed), but I think there are cases where the variable losses due to friction might make the hilly case more efficient than the flat.
(Yes, I realize that chain friction is not the dominant factor in the real world. It's a stylized example.)
I grew up in a very hilly area plus I have done a few continental rides where hills can be graded nicely and go on for 10 - 20 miles with little change of gradient. The hope to coast up the other side of the valley never really works out as well as one might hope, with a road that goes down a big hill you are invariably pedalling on the lower reaches of the down hill part, even if you were doing a good 30+ mph at the top. This can be due to the valley heating during the day giving a prevailing headwind due to air expanding.
Meanwhile, in the steep hills I grew up in, you can get a measured 40+ mph, conservative guessing (I would be boasting if I mentioned top measured speeds as they can be quite incredible but 40 mph is the town limits speed and it is cool to exceed it on a bike). Clearly this speed scrubs off with aerodynamics not being favourable. So you really do not blissfully roll up the other side, roller-coaster style.
On a daily basis I go over an arched bridge that does have a hill leading in to it. So you can coast down the hill, up over the arch and on down the other side. The fun is to not pedal over the bridge, to be in 'roller-coaster' mode. This feels good, and easy, but there is a psychological factor going on here. One's brain is distracted by the 'roller coaster' (or traffic) and not really noticing how much of a slog things are.
Essentially the only way things could work out anywhere near how you imagine is if there is no atmosphere. The cost of speed is aero and you just do not get the free ride up the other side of the valley, period.
If it was quicker/more efficient to go up and down hills we wouldn't have land speed records be they by bicycle or rocket car set on dead-flat courses, would we?
With the sibling reply regarding undulating paths, that is part 'mind trick' as it is mentally stimulating going up and down like that. It is just an illusion...
However, I can in part rescue your line of thinking on this - muscle groups... I actually like hills and you can use your arms, legs and plenty of muscles in between to 'conquer' a hill. On the flat you are more likely to just spin (unless sprinting). Maybe if you factor in the baseline power your body needs for pumping blood around, maybe that could make things 'possible'.
But the more I think about it - no... Look at motorways and trucks. Trucks are more efficient than cars even if they have lots of wheels and no obvious aerodynamic considerations. Lorry drivers do not choose the undulating 'A road next to the motorway when one is available. They stay on the motorway doing their most efficient speed (as that is how to make a profit). Hills that any car or lorry could go up are cut through with motorways, to make things as flat as possible.
That's a total non-sequitur. Land speed record attempts happen in flat places to keep them from turning into AIR speed record attempts.
The combined highway/city mileage on the sticker was 24 mpg, and I've been getting 27 or 28 mpg for the entire 2 years I've owned it. For a while I was commuting between Denver and Boulder (about 45 miles each way) five days a week and taking it up to the mountains for hiking or skiing every weekend, so it's been over a wide variety of terrain.
I'm using the numbers on the in-car, computer, though, so maybe I should double check...
Manufacturers report fuel consumption during a controlled environment, with specific driving habits, etc.
Real world people drive insane (at least in the US), and most wouldn't even re-pass their drivers-license test, so most assuredly do not have the best driving habits.
So drawing the conclusion that manufacturers are "lying" from the discrepancies between those two data sets is ridiculous.
> So drawing the conclusion that manufacturers are "lying" from the discrepancies between those two data sets is ridiculous.
Perhaps you should pay attention to actually what I said, not what you think I said. I didn't say GM was lying, I implied their numbers deserve extra scrutiny.
Saying a manufacturer deserves extra scrutiny can absolutely be inferred to be an accusation of them reporting false numbers, i.e. lying.
My reading comprehension isn't at fault here.
Secondly, it's still irrelevant.
You would have to prove that an improvement at throttle position 0.10 over 5 years equates directly to an improvement at throttle position 0.40.
How an engine performs in condition A has no inherent relation to its performance in condition B.
So yes, I stand by what I said. Maybe before accusing people of "not paying attention", you should look at your own language and see if it's ambiguous?
> My reading comprehension isn't at fault here
Except that I very clearly said "I can't discount the possibility of something else is going on, such as an influx of a different type of car for GM over that period, I haven't read yet how they normalized the study and accounted for things like that."
> Maybe before accusing people of "not paying attention", you should look at your own language and see if it's ambiguous?
You ignored clear text from me saying that it didn't necessarily indicate GM was at fault. What am I supposed to infer from that?
As to the matter at hand, you still seem to be under the impression that driver habits can account for a change in the numbers we are talking about, when that would mean that GM drivers specifically drive very differently than all other car drivers in the report. We are talking about number across the industry, categorized by manufacturer. Everything listed on the graph in question shows automakers overreporting gains, which could be driver habits. GM specifically shows vastly different numbers from event every other manufacturer, not just the reported numbers. I fail to see how driver habit accounts for a specific manufacturer being so out of bounds with it's own reported numbers (keep in mind engines are often shared across multiple manufacturers).
Have you looked at the graph on page 13 yet?
I didn't ignore anything.
I said the source of data is not irrelevant. That's my entire argument.
And I was specifically refuting your thesis that the source of data is irrelevant.
and, "as to the matter at hand", yes, driver habits can account entirely for the discrepancy in numbers. Flawed data can account for it. Poor sampling can as well.
The report seems to have come from a self reporting site in the EU. Are you asserting that a US car manufacturer has sold a uniform distribution of make/model/engine cars across the globe?
Are you also asserting that this site is getting a proper randomized sample of the car-buying population, such that they don't all have a similar complaint? In my experience, the people who report such things are one of two cases 1) Extremely Satisfied, or the much more common 2) Extremely Dissatisfied.
Are you then also asserting that if GM optimizes for test conditions, which they believe to be similar to normal driving habits, that their engines would be optimized to perform well under conditions that people actually drive in? That's just sloppy. That's like comparing data from your Dev environment to that from Production, I believe there have been a few academic articles to refute that as well.
But, ultimately, are you asserting that we should just accept the source of data as a source of truth, and never question whether or not that it's valid? Should I just go buy a bunch of tabloids and take that as my "new news", since.....the source is irrelevant, right?
Please stop trying to tell me what my thesis is, as you've misunderstood my statements. The portion of the comment I was responding to is "In my anecdotal experience, drivers tend to get much lower than the manufacturer mileage because they optimize for things other than fuel economy (e.g., speed)." That, by itself, is irrelevant to the question as to why one manufacturer has vastly different numbers than another. As to testing methodologies, yes, this could entirely be testing error. I've never stated my opposition to that possibility. I have repeatedly stated my only intention was to say these numbers need more investigation.
I'm done trying to discuss this with someone who ignores what I actually state in favor of what they decide I must be implying.
This entire argument would have been over had you clarified what you thought was irrelevant, instead of arguing over stupid minutia.
Now that you clarified, I actually agree with your point, that the data points need to be investigated.
No, actually it isn't. The controversy is over manufacturers tuning their vehicles' engine behavior to give economy for the tests and for the tests only. By your criteria, that's not a problem but VW has already been bitten really hard by the revelation that they did this.
...You would have to prove that an improvement at throttle position 0.10 over 5 years equates directly to an improvement at throttle position 0.40....
The EPA has essentially said that if this isn't a least somewhat true, the manufacturers are breaking the law.
They weren't simply optimizing for test conditions, they were outright lying during test conditions.
that's what the EPA is saying is against the law.
Here's the thing, and this is my main point:
If the EPAs test conditions reflected normal driving habits, there would be zero difference between Manufacturer reported numbers and real world reported numbers.
If the EPAs test is completely different from normal driving, then it stands to reason that there is no inherent correlation between manufacturer numbers and reported numbers.
IDK if you've ever been through an emissions test (like the ones GM actually goes through), but they're a complete joke as to simulating real world behavior.
Edit:Format
If you make laws that can't be verified then you can't enforce them. So you test for things you think you can actually test and hope everything works out.
Wiring up an exhaust sensor to everybody's car every time they need to renew their tabs and having them drive around the city is so infeasible as to be laughable. So they put your car on a dyno or even have you put it in neutral with the parking brake on and have you rev the engine a little bit and see if the tailpipe is a mess.
Nevermind that a lot of cars belch smoke only under load.
[1] http://asmunder.github.io/2015/09/A-histogram-of-CO2-emissio...
IFF the EPA's regulatory test procedure accurately described/expressed normal driving habits, then the only way that numbers would differ between the real world and the reported numbers would be fraud/lying/alteration, like what Volkswagen Group engaged in (let there be no mistake, it WAS fraud/lying, not a case of poor optimization).
BUT the EPA's regulatory test DOES NOT accurately depict normal driving conditions.
In the current case, a manufacturer has to:
- Realize and Formally accept that the test procedure is inaccurate
- Optimize for:
- Simulated driving conditions, aka the Test Procedure
- Real life driving
Depending how far out of wack the test procedure really is could explain the entire data-set.
Now, when you talk about GM, remember this is data from Germany, so GM essentially means Opel. Now I believe that before the quite successfull Insignia which launched in 2008, Opel were mainly known for cheap and efficient and small cars like the Corsa and Astra, while now they have a more premium lineup, and "Turbo" versions of several models.
And yeah, I've driven a Chevy Spark, and that thing was so slow I could get out and walk faster. I could totally see people driving with their foot to the floor in it.
Does not matter. Your argument is something like, that by dumb luck auto manufacturers produced good emissions results and terrible results in the field.
As understand it, the EPA is saying that if a manufacture is engaged in your two stage approach, "Optimize for:- Simulated driving conditions, aka the Test Procedure [and achieve high fuel economy] - Real life driving [and achieve high power, low fuel economy]" then they are engaging in systematic fraud and are going to get hit big time. You seem to think it's just a matter of technicalities in the test condition. I'd like references for that.
The EPA has a set of standards, and manufacturers optimize for those. That's it.
Cheating != optimization. Cheating is like a kid copying someone else's answers. Optimization is studying before the test. Completely different things. And optimization isn't illegal.
If you still don't get it, I don't know what to say, I can't explain it any further.
However, I have good evident that VW's optimization was considered criminal in this instance. And Indeed, since many manufacturers do this, things are pretty dicey.
"“Developing an engine software to optimize certain aspects of an operation cycle that you know the parameters of is a challenge, but it is very possible,” says Thiruvengadam. “Knowing when to switch to the EPA-favorable cycle is the trick; it could be set up to detect the absence of steering-wheel movement, or, and this is known, we often turn off the traction control for testing purposes.” Either way, the result is the same: it turns the emissions controls on for EPA testing and off for real-world driving. Somewhat ironically, the presumed benefits of turning off the controls for normal driving include improved fuel economy and engine power." [1]
[1] http://blog.caranddriver.com/how-volkswagen-got-busted-for-g...
The official .gov propaganda is a 3% penalty, but self reports vary from 5% to 15%. E10 is a thirsty fuel and people buy a lot of groundwater at gasoline prices, which likely accounts for some variation.
We aren't trying to determine if the companies have an improper ideology.
That is, for GM cars alone, people are reporting not just a lack of increased fuel economy, but that it's gotten significantly worse. Whether it is accurate or not, it indicates something very wrong, either in the testing or in those cars, and that deserves some serious attention IMO.
Edit: s/fuel economy/fuel emissions/ Graph says economy, subtitle say emissions, text says emissions.
GM will get another pass because it is "too big to fail."
This has to stop. Execs need to start going to prison.
Somewhere along the line I imagine there are those who are terrified of missing those targets and perhaps losing their jobs and resort to bending the rules a bit to hit their goals. And there's a very good chance that these people aren't at the top.
The same was most likely true in the subprime mortgages--I imagine that some of the worst actors in that weren't necessarily the people at the top, it was the guy who is decidedly mid-level who is looking to make a nice bonus to put in a swimming pool for his kids.
And to figure it all out is going to take years and years of investigations to assign blame (whether in this case or in the subprime case). By the time it's sorted out, it could be a decade after the fact, and even then people have moved on to other jobs, records are difficult to dig up, and at the end of the day, what has been accomplished?
Of course if there is blatant wrong-doing, execs should absolutely be punished (the peanut company CEO comes to mind [1]). But it's extremely difficult to pin down blame on any one person, exec or not.
[1] http://www.reuters.com/article/2015/09/22/us-usa-georgia-sal...
Lock a couple of these people up, and suddenly they'll start caring a lot more about the legality of what their underlings are doing...
You can't just investigate, the nature of large power structures is that some underling will take the fall.
Breaking the rules for economic advantage should be met with new rules to force economic disadvantage. Put a 2% tax on total revenue for the next X years, possibly with the addition of a fee based on perceived past benefit. Honest players in the market will reap the lower cost of doing business, and better business practices will prevail.
Again - with taking the credit comes taking the responsibility. I'd like to see the law amended as such.
[1] interestingly, this is apparently a misuse of the phrase as Truman used it. But popular usage, etc. http://nymag.com/daily/intelligencer/2012/10/buck-stops-here...
Maybe if some of them got hit with actual penalty, the rest would learn to pay attention? I dont understand the apologetic attitude.
While they speak about fuel consumption and even speculate with numbers, this is not backed up by the data.
Report contains only data about CO2 emissions.
This could happen for example when the engine could not take enough air to burn efficiently (for example because it is stationary).
Unless we have also fuel consumption we could not know which case we are dealing with when we only see CO2 emissions.
For example when the test only measures (and prioritises) CO2 emissions, injection software may decide to use more fuel in inefficient manner to reduce the CO2 emission and then use exhaust filter to capture the extra particulate matter. Well, it is only a wild speculation, but it could be.
Neither compares to CO2, as a fraction. You are simply wrong. CO2 emission is proportional fuel consumed.
The problem is that the report authors do not explain their methodology and interchange freely fuel consumption and CO2 emissions without clear explanation (did they measure CO2 emissions directly? did they calculate it from fuel consumption?).
This is not proper reporting in my mind.
Beside they base their reporting on self reported (i.e. not automatically measured) data from http://www.spritmonitor.de/ that does not provide any objective information about the driving cycle.
See for example these two 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)
It is about 34% difference. Why? No idea.
Well, maybe the first driver drove very carefully. Maybe the other car is broken or the driver likes to accelerate a lot or is driving on the hilly terrain.
It is also not known how many kilometers were driven on the city roads or highway as they are hard to separate in the data.
We also do not know which driving mode (eco, normal, sport etc) was used as it is not reported.
Car makers report different fuel consumption or CO2 profiles. Against which was comparison completed?
I think that this is sensationalist reporting with an agenda that is not well executed.
How deep does this rabbit hole go :( Here in Ireland the motortax for cars newer than 2008 is based on CO2 emissions, if motorists find their tax rising due to cheating by car manufacturers thats an unexpected and direct cost to their wallets.
I'd buy one if I did enough miles. It's not worth it for a few thousand a year. Even having a petrol car sitting on my drive is an expense of marginal justifiability.
Were we led astray? Or are we discussing the last few percentages beyond an actual advantage over gasoline engines?
Statistics like these should be taken with a grain of salt (for one thing, city delimitations are fairly arbitrary), but the details are not worth haggling about: the point is that Paris is not at all representative of large European cities.
[1] if Wikipedia can be trusted on this https://en.wikipedia.org/wiki/List_of_cities_by_population_d...
http://www.nasa.gov/topics/earth/features/health-sapping.htm...
Noise isn't a good predictor though, a muffler is a drain on efficiency.
Co2 may have a deleterious effect in 100 years time, but is not an issue for air quality today. In any case, passenger vehicle c02 emssions are a rounding error in the scheme of things.
Meanwhile, particulate pollution and Nox are very real issues affecting millions of people today. It's stupid to push diesel over gasoline for c02 reasons.
Part of the reason VW cheated was because the USA didn't fall into this trap and allow more lax emissions standards for Diesels - all fuels are held to the same standard. So they took the Euro engines and added the defeat code.
The USA is correct on this one.
The focus on passenger vehicles is idiotic though - the amount of Nox and particulates pumped out by a single container ship is immense compared to a fleet of passenger vehicles. Then add trucking, rail, stationery equipment etc...
Cities should be optimising for electric propulsion and punishing diesels. That makes sense for air quality right now, and if co2 proves to be an issue, it is easily fixed by switching the generation source to Nuclear or Hydro.
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...
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.
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).
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.
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.
Did you test your water for drugs this morning?
Did you check them yesterday?
We all live at certain layers of abstraction.
probably not
http://rockyroadblog.com/caveat-emptor-vetting-mpg-claims-30...
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.
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.
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).
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).
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.
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.
Therefore any claim about CO2 emissions equates to a claim about fuel consumption.
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.
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]
Driving style used (Moderate, Normal, Fast),
Roads driven (Motor-way, City, Country roads)
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.
edit: typo
Pension and 401k plans are typically diversified across a broad range of stocks, so they won't be heavily impacted by a single company's stock price dropping. On the other hand, executives and board members, who are actually responsible for the company's actions, will typically have a large amount of that company's stock so they will be much more heavily impacted by the stock price dropping.
This doesn't require new enforcement or new taxes - a large part of the purchase price of petrol is tax.
Anyone who spent 10 minutes looking into this in the past years could've told you that, and it wasn't some big secret. A lot of it was stuff everyone was doing, like fitting certain tires and inflating them such that the rolling resistance is reduced. At the end of the day, there are limits to those gains and everyone does it, so in can't set you apart from the competition and once the basic manipulations are exhausted and the emissions goalposts are moved you can't make gains anymore without actually improving the car. Further most of these are for CO2 emissions / fuel efficiency, which is different from the VW fraud which was about NOx emissions.
The difference with the VW case is that VW essentially defrauded the test by building a device that measured various factors to establish whether it was being driven normally or whether it was being tested. In the former case it'd shut down (allowing 35x the legal limit of NOx emissions into the air while driving), while in the latter case it'd dampen the emissions (at the cost of engine performance, which is why they shut it off during regular driving). That's a different level of fraud, one that has very few bounds and can change results by much more than an order of magnitude, and is hugely controversial because it makes every test meaningless in the short, medium and long term and isn't practiced by everyone, and so different from manipulating tests by e.g. inflating tires which can still produce meaningful test, benchmarks and comparisons, when you start building 'defeat devices' all of that goes out the window completely.
(Or more likely a mode that kicks in when non test driving is detected)
If you keep pushing your engine consumption downwards to the ridiculous levels we see now (<.5 liters 10km), what happens is the "drag cheat" actually becomes a large percentage of the consumption.
Just goes to show that the cars should be designed without large door gaps or outside mirrors (cameras instead) and so on, since they seem to add significantly to the consumptions that that is where the effort should be put.
As a consumer, I really don't care much, I just get consumption data from some independent source such as a magazine or website. Having manufacturers self-test and self-regulate reminds me of the financial industry in 2008. It just won't work.
Anecdotal reporting online is a joke. You will find endless car forums with people boasting about how they consistently get 25mpg in their V8 sedan. Gimme a break.
What I'd love to see is some service/app that was able to gather real world data from owners of the same type of car in the same area as me along with general stats about their driving style. This would have to be automated to be accurate.
There are some markets, like voting machines, where requiring open, buildable, verifiable code is good practice. Cars might be another.
See this story about the need for open source for large publicly used systems: http://www.nytimes.com/2015/09/23/nyregion/volkswagens-diese...
Voting machines could appear to work perfectly --
except during the first Tuesday of November, when it
undetectably switches a few percent of votes from one
party's candidates to another's.
In hindsight, those agencies should have been staffed better. Additional legislation (which is sure to come, if only so Congressmen can appear to be doing something about the problem) wouldn't have helped, as the cars didn't meet existing laws as it was.
It also speaks to the responsibility of the auto press for the NOx issue. They routinely report real-world MPG ratings for cars ("in our driving, we got __ MPG"), but haven't bothered to test real-world emissions despite all the other expensive gear they use to test car performance. Manufacturers and governments should be accurate and honest, but it's also the press that should be routinely verifying their accuracy.
Example of skepticism at the "extremely optimistic European cycle":
http://www.caranddriver.com/reviews/2017-audi-a4-prototype-d...
Then why does this report compare NEDC numbers with user-submitted real-world consumption? Since car manufacturers have increased power output while keeping NEDC consumption relatively constant, rather than the other way around, you need to drive very carefully to get close to the official numbers. It should be obvious that the more powerful an engine is, the more fuel it can burn in a period of time, if you go full throttle. Which is why they find that BMW and Mercedes deviate more than the average. Dear "Transport & Environment", why do you think do people buy fast cars?
This is the ICCT report TFA is based on: http://www.theicct.org/sites/default/files/publications/ICCT...
I have a car with 2.5L turbo engine and I can get from 13.5-28MPG from a tank of gas depending on a number of factors, mainly on how I drive, but also what fuel, how loaded-up the car is, and tires. I suspect that automatics with turbo or supercharged engines with start-stop have the greatest difference in real world v test performance. And yes that is because of how people drive compared to the test.
But it's not the cheating story of VW, continued - that was about nitrogen oxide pollutants which was up to 40 times above what is allowed in the US.
From the report:
> All carmakers have been exploiting ever more flexibilities in the current official tests during 2013 and 2014, but detailed results from Spritmonitor in Germany (Figure 4) show that cars produced by Daimler, PSA and GM exhibit the largest realworld gaps, around 40%. However, in the past two to three years all major carmakers (with the possible exception of Fiat) have become more adept at using flexibilities in the tests such that all carmakers now have an average gap of 25% or more (as against a maximum gap of only 10% in 2001).
As I understand "Spritmonitor", as a private person, you can record your fuel data (from your receipt) and your odometer to calculate the mileage you can go with your car. No details about the driving behavior that has an impact on how much CO2 is emitted.
http://www.spritmonitor.de/en/overview/50-Volkswagen/0-All_m...
I guess that's not the perfect, reliable source - everyone can use the portal and add his favourite car. But for sure, I'll never reach the official 5.7 l/km with my car ...
There is still the issue that high efficiency, usually means running the engine at high temperatures which generates far more NOx gases.
We should be taxing the amount of fuel used.
Every engine and car produces different environment waste.
For example a Tesla S produces much more carbon in it's production than a gasoline car. There are also other toxins which are produced concerning different type of cars.
A diesel produces NOx but can reduce it with filters.
Just taxing the fuel used is just stupid.
Lab results never represent real street results. How could they? People drive differently and the outcome is based on many aspects that you can't reproduce in lab conditions.
The issue isn't that we can't "represent real street results", the issue is that manufacturers took deliberate steps to alter car behaviour with the intention of obtaining better test results than would be present outside the tests.
It's the same with smartphone and notebook batteries. Tell me, when was the last time, you actually got 9 hours of battery live (in case of a MBP)?
Don't get me wrong, i see it the same way as you are, but this is an issue that you can find everywhere not just in car manufacturing.
For example, a lot of power supply companies try all kinds of tricks to game the efficiency test systems.
And, if you got a bad battery that doesn't live up, they'll replace it at no charge.
Battery life declines with age, however.
The article points out that 1/3 of improvement in past 3 years to meet regulation requirements was real improvement and 2/3 was just manipulation.
It doesn't matter that people drive cars differently than they are tested in cars, to illustrate it they highlighted that due to those manipulations that difference now can be as high as 50% which is beyond claims that people drive cars differently than when they are tested in labs.
Why? You have just been shown corporate cheat on tests. Why you would ever assume this has something to do with fuel type? I expect Tesla cheat as much as MB or BMW in their "range" test. And if you believe otherwise you are just someone who doesn't learn from his experience.
Top Gear got complaints for doing the same thing to (I think) a Leaf.
But really, Tesla develop cars with high performance characteristics, and then people complain about "unrealistic driving conditions" when people drive them as they are designed?
Tesla could easily program the cars to accelerate moderately and with maximum energy efficiency, but they would't be able to command $80,000 price tags if they did that.
People who spend Tesla, Mercedes, or BMW money on a car, by and large, don't give a shit about economy.
Could you perhaps cite any data, any at all? It's not like we don't have a LOT of Tesla owners out there who are obsessively testing this, every day. Do you think they're just all part of the conspiracy?
If an electric car is much less efficient than claimed, you'll notice as soon as you try to drive to the limit of your car's range, because it won't get there.
I expect Tesla cheat as much as MB or
BMW in their "range" test.
Personally I'd expect a tesla that had just rolled off the production line to exceed the specified range easily.
[1] http://industrial.panasonic.com/lecs/www-data/pdf2/ACA4000/A...
It's hard to cheat in an electric car. Few people care about efficiency directly, but most electric car drivers care deeply about range, and range is just battery capacity multiplied by efficiency. If Tesla were cheating so they could lie about efficiency, Tesla owners would notice pretty much right away that they're not achieving the range they should.
The only practical way for Tesla to cheat would be to ship a larger battery than they say they do, and then fudge the numbers from there. Given the current cost of batteries, this would be an incredibly expensive cheat, and it would be tough to hide from the tinkerers who tear down battery packs to see how they're built.
My personal case is a Zero motorcycle, but I've heard confirmation from owners of other kinds; the range it gets is more or less exactly what they state for the test conditions (straight level ground, no winds, etc etc). Mine did in fact improve when I adjusted the aerodynamics, but that's another topic.
"Pushing the brake pads fully into the callipers reduces rolling resistance" is apparently one way. That makes me ask the question, why don't we do this already? If it reduces rolling resistance it probably also increases brake-pad life. That'd be a win-win for drivers.
If you change your own brake pads you know that after you finish it can take two whole presses of the brake pedal to get the pads to contact the rotors
Would be interesting to know what designs of pads/jaws dissipate the contaminants better?
With the brake cylinder fully compressed (as they did for the test), it requires several full pumps of the pedal to bring the pad into contact with the disk. This increases braking distance, which is generally considered a bad thing.
There could also be beneficial side effects to having the pad in contact with the disc at all times, such as preventing water/fluids/dirt to coat it. I'm just guessing here.
If you've tried hopping in a car from the past few years after driving a much older car you (and you passengers) will have probably noticed this! It's very common in modern cars to have much shorter brake pedal travel, so what would bring you to a gentle stop in an older car will be somewhat more abrupt in a modern car.
This is achieved by having a shorter travel pedal, which is then heavily assisted by the brake servos so it is not horribly heavy to apply. This is nominally for safety's sake, as it reduces the time between seeing a obstacle and the brakes being fully applied. And since all recent cars have anti-lock braking and stability systems it doesn't matter so much if the driver can't control the braking pressure quite as precisely.
> I suppose you could have a more clever system that would move the brake faster until it touches the disc and then behave normally but I suppose that for such a critical system constructors and regulators are very conservative.
Exactly, as I mentioned to the other commenter, it's preferable to have a simple, non powered mechanical system in place to stop the car in the event of bad things happening. Adding extra bits to this system, with the vast R+D cost involved, for marginal increases in fuel economy would be hard to justify for most car manufacturers (especially since the fuel economy saving would benefit the users pockets, not theirs).
Indeed, most cars use a servo that uses vacuum 'pressure' harvested from the engine to assist with braking and reduce the amount of effort the driver needs to expend. However, you can still brake with a non-functioning servo, all be it with a much reduced braking performance.
It's a similar reason why even very modern cars (bar a few, the Infiniti Q50 being one) still use direct mechanical linkages (heavily assisted in many cases) for steering, despite the steering rack, column and rods taking up room and complicating engine bay arrangements. If it all goes really wrong, you need to be able to steer and stop the car.
When I bought my car (10 years ago) and read reviews, a lot of them say here's what the epa said you'd get for mileage, and heres what we actually got. There is always a difference (maybe 10%). But if it claims 30 mpg and you are getting 17 , I like to think more than few people might notice.
Part of the reason VW was accused of cheating on emissions was it helped mileage.
edit: as pointed out, its 50% more fuel... But still a noticeable difference..
EPA (USA) tests aren't really real world and they don't just drive the cars. Well they drive them on a dyno on a preset pattern (see the picture in the link).
https://www.fueleconomy.gov/feg/how_tested.shtml
they measure emissions to estimate fuel consumption.
The whole reason manufacturers are moving to small displacement turbocharged engines over large displacement naturally aspirated engines is because the EPA MPG tests never run the engine in a range where the turbo is doing much. Put the car in the real world and the driver's lead foot makes the turbo kick in, killing fuel economy.
Ref: http://autoweek.com/article/car-news/mpg-or-performance-its-...
Turbo engines can consume vast amounts of fuel when opened up to full throttle. Modern turbo engines are also very easily remapped for extra power (and consumption) just by changing the boost control.
All the added complexity and cost just to match emissions requirements, which are all negated when the driver 'puts the boot in'.
Turbos are the ultimate cheat device.
What's up with that?
A computer science analogy to this would be if I gave you an uncompressed image and you had to develop a compression algorithm that made the image as small as possible, you could likely come up with a really good solution. But your algorithm most likely wouldn't do as well on any other image.
I think that a feasible solution to this will be to test under a wider range of conditions and add (statistically defined) noise to the testing procedures. The added cost of additional testing would be very small in comparison to the cost of a vehicle development program.
A good overview of the different drive cycles can be found here: http://www.car-engineer.com/the-different-driving-cycles/
That analogy doesn't hold. It's more akin to developing two compression algorithms, one for the general case, and a specific algorithm which is used only when your image is detected for better than the general compression performance use case.
It is entirely fair to blame the manufacturers for this. Gaming emissions results required effort to accomplish, and is completely unethical from an engineering standpoint.
The vehicle manufacturers optimize the engine calibration to the drive cycle they are trying to beat. That is why a US-spec BMW has a different engine tune than a Euro-spec BMW for example, the drive cycles are different.
A 50% increase in fuel completely changes the cost proposition.
"Gallons Per Year" would be much better.
Move closer to work, carpool, take public transport, ride a bike, work remotely. Benefits from these things would dwarf any incremental improvements from EPA ratings.
The problems with the emission measuring and also fuel measuring was known for long now and in the EU, many wanted to change the measuring methods -- but for example the German government did always block such advances.
In my opinion, not only the car manufactures are guilty, but even more the politicians that made it very easy for them to cheat on us all. The additional expenses (at the gas station and with the bad air) carry the consumers.
VW is only the tip of the iceberg.
You want low NOx emissions, you need richer mixtures, and thus higher fuel consumption and higher CO2 emissions.
Isn't that where catalytic converters come in though?
Rules in conflict surely are required by the chemistry of the situation, the companies have to search for the local minima in order to comply.
Diesel exhaust is too oxygen-rich for the cat to effectively catalyze the NOx. That's why recent passenger car diesel systems have a Diesel Exhaust Fluid system.
The Chevy Cruze Diesel was as clean as promised in the US version but the European version may not be as clean[1].
http://www.thetruthaboutcars.com/2015/09/tech-dive-chevy-cru...
When your speedometer shows 100 km/h, it is permitted that true speed is 90 km/h, but it is not permitted that the true speed is 101 km/h. And the same variance applies to odometer, of course.
Things like tyre wear and pressure have a noticeable impact on what both meters show, and manufactures have to stay on the safe side, by law.
That said, I believe the odometers are typically bang on, which would mean the mileage calculation should be accurate. Or could be, if they wanted it to be.
Do you engage the throttle and brakes more than necessary?
While they speak about fuel consumption and even speculate with numbers, this is not backed up by the data.
The same thing goes for bodybuilding, anyone has another example?
One of the Marxist critiques of capitalism is that if an employer wants to do certain good things (like treat his workers well, pay more salaries than the bare minimum, take care of the environment and so on) he can't do that because that will raise the price of whatever he is selling and he would be outcompeted by his less altruistic rivals and go bankrupt. So every business owner has to be a bit of a psychopath to survive.
Obviously this is only as good as the way I drive (or my wife) and is heavily dependent upon if I hit traffic, mostly drive in the city or go on a road trip.
It really is an interesting thing to keep track of.
The report, on the other hand, could try to compare like-for-like. For example, they could give separate results for high-mileage drivers and low-mileage drivers. Or split the results by average speed, to try and isolate long-distance motorway drivers from short commutes.
My 2009 Jetta was rated at 29 city, 33 combined and 40 highway . Based on my fuel records, I got 33 city, 36-38 combined and 50 highway.
That means it out-performed the EPA estimates by 25% highway, 12% combined and 14% city.
Far too many race from light to light, keep on the gas even when going downhill and over the limit, brake late and even run with tires under inflated.
anecdotal, my current car a s28 Z4 uses a four cylinder turbo. 23/34 I think are the official ratings, I have yet to average a tank under 30 and did 40 on pure highway at speeds over 70. Granted its a manual which lets me abuse the rev range a bit more than the 8 speed auto offered but its simply down to learning to drive your car within its best performance parameters. I still have fun, run it up fast, but mostly just drive relaxed.
Does it mean that some cars are not performing to what companies claim. I am quite sure they aren't. I could not get a 2013 Mustang V6 above its EPA AVG to save my life.
"Mercedes, BMW and Peugeot models emit 50% more CO2, new study reveals"
The report does not provide the data about fuel consumption.
1. offical does not reflect real world. 2. defeat devices.
If every car manufacturer is using defeat devices it really shows how poorly EPA requirements have worked. Blame car manufacturers, sure, but they're supposed to be selfish. That's how economics works.
So much for government protecting the people from corporations and their sole quest for profit.
No vehicle meets manufacturer specifications in this regard, electric or IC.
To be clear, I am not saying this as a negative. I am simply stating it as a fact.
I have not taken care at all to drive my Model S in an efficient manner, and I still have an average of 315Wh/mile over about 8,000 miles of driving so far, where 300Wh/mile is rated efficiency.
Beyond that, the truth is you cannot get the rated range because that would mean draining the batteries to zero. Real range anxiety, depending on where you drive, starts to come in somewhere below 50 miles from fully drained.
You also have a difference in performance between summer and winter driving. If you have a short daily commute, the combination of the "off" state drain on the battery overnight and the car warming or cooling the battery pack while parked in cold or hot weather can have an impact on available range and performance.
BTW, I am NOT saying any of this is bad. I am simply saying these are realities of the contrast between advertised specifications and performance under real life conditions.