281–290 of 336 posts
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50% more fuel than official results would be like claims 30 mpg and actually getting 22.5 mpg.
Consuming 50% more fuel than 30MPG is 20MPG, not 22.5MPG: 30 miles divided by 1.5 gallons equals 20 miles/gallon.
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I think you should reconsider "physically impossible". Sure, in some idealized situations, the statement you're responding to would be wrong, grievously wrong. 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 strat…
I read years ago that pulsing was the most efficient strategy. Engines have very different efficiencies at different rpms and power settings. The idea with pulsing is to try to operate it at its most efficient rpm and throttle setting, which of course rarely corresponds to the speed over flat ground you'd like to be travelling at. Hence pulsing.
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I thought the same. 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). My dad taught me lots of tips on conserving fuel and thankfully I've exceeded the sticker numbers on every car I've owned.
Just stay off the brakes as much as possible. No big secret really.
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> 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.
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> 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? 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. F…
> And I was specifically refuting your thesis that the source of data is irrelevant. 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…
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.
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Consuming 50% more fuel than 30MPG is 20MPG, not 22.5MPG: 30 miles divided by 1.5 gallons equals 20 miles/gallon.
True. I was thinking 100% more would be 15 MPG so 50% more would be 22.5. Thanks for the correction.
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I cannot imagine a cyclist imagining this to be true! 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'.
Consider a different visualization: what if instead of a hill, you were crossing a valley? Starting at the top of the hill, you coast down and make it most of the way up the other side. Are you certain this will take more energy than pedaling the whole way across the flat? 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…
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The reason why it matters is that air resistance is proportional to the square of your velocity. At high speeds that term dominates.
Due to some physics things that I don't understand, it actually ends up proportional to the cube of your velocity. source: presentation by Dr. Rizzoni at Center for Automotive Research at OSU
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The whole controversy is over manufacturers reporting false numbers, i.e. lying. 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 positi…
I'm not sure what your definition of alter is, but for me to alter means to lie . 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 wor…
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.
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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 bec…
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.