GM to unveil electric car prototype

<div class='quotetop'>QUOTE(Allannde @ Nov 13 2006, 12:46 PM) [snapback]348306[/snapback]</div>

That seems a little extreme... to make it easy, lets say you go 100 miles:

@12mpg, you use 8.333 gallons
@14mpg, you use 7.143 gallons
Total savings: 1.19 gallons

@33mpg, you use 3.03 gallons
@100mpg, you use 1 gallon
Total savings: 2.03 gallons

So i would say thats pretty much debunked...

If two cars have their mileage increased by the same quantity (say 10mpg), then whichever one was lower would be impacted more - your gas savings over a specified distance would be more. But increasing the lower one by 17% while you increase the higher one by 300% doesn't have the dramatic effect you were going for.

For those more mathematically inclined, we can do some further calculations to determine the exact break even point in fuel savings for proposed increases in two cars:

car 1: w = original mpg, x = mpg increase
car 2: y = original mpg, z = mpg increase

1/w - 1/(w+x) = 1/y - 1/(y+z)
y(y+z)[(w+x)-w] = w(w+x)[(y+z)-y]
y(y+z)x = w(w+x)z

Find the intersection of those two quadratic equations, and you get your solution.

Now, lest go with the 12mpg SUV versus a 33mpg sedan:
33(33+z)x = 12(12+x)z
1089x + 33xz = 144z + 12xz
1089x = z(144-21x)
z = 1089x/(144-21x)

Plug in the 2mpg increase for the SUV:
z = 1089*2/(144-21*2)
z = 2178/102
z = 21.35

So in order for the sedan option to be better in terms of gallons saved for a given distance, it would have to be increased by 22 mpg, not 67.

 

<div class='quotetop'>QUOTE(Allannde @ Nov 13 2006, 02:10 PM) [snapback]348361[/snapback]</div>

Which just reinforces what i said (and puts it in an easy to look up column format). 12mpg = 8.3 gallons, 14mpg = 7.15 gallons, 33 mpg = 3 gallons, and 100mpg = 1 gallon... so the gas savings are still more for the sedan over the SUV (2 gallons saved versus just over 1)

Take a look at the spreadsheet i just made:

Start by putting in the mileage increase for automobile A. then look up the initial mileage for automobile A on the left (in this case, 12). trace that across to the column that corresponds to the initial mileage for automobile B (in this case, 33) and the value in the box will be the mileage increase that would be required for automobile B in order for the two to save the same amount of gas - if the increase is higher, the automobile B "wins", lower, automobile A "wins".

Any cells that say "error" are ones where the gas savings from auto A exceed the amount of gas used by auto B for the same distance. If needed, the whole table can be dragged out further (even the row and column labels) to give more information for, say, an increase to a 60MPG car.

Mileage increase spreadsheet

This should come in handy in any of the future discussions (it seems to pop up every now and then) on which vehicle is "better" to be turned into a hybrid for a mileage increase.

 

Like i said, it will if you have the same increase in mileage - 12 to 14 versus 30 to 32, for example. But my point is that the example you initially gave - 12 to 14 versus 33 to 100 - the "gas sipper" saved more gas over the same distance - 2 gallons for the sipper versus 1.15 for the hog.

the first two columns in your table are equivalent, and the third is the gas used to go 100 miles at the stated mileage in the row - very nice and concise. However, in order to see the improvements from a mileage increase, you need to subtract one row from another - say the 16.5 from the 19.5 to see the savings from the increase. and as stated above, doing this subtraction shows that the sipper does better with the example you gave.

My table took that one step further - it provides an easy visualization for determining the "break even" point between increases - you put in the increase for one vehicle, and trace the graph to see what the equivalent increase is for the other. a 2mpg increase for a 12mpg vehicle would be equivalent in savings as a 21mpg increase for a 33mpg vehicle. So it's easy to see that the proposed increase of 67mpg (100-33) is much greater than the break even point, meaning the sipper will save more gas for the same distance.

 

Many people would agree... why get an SUV when you can get something smaller that gets better mileage, especially if it's cheaper?

There are several answers to the question.

One, and SUV is seen as a kind of status symbol. While it's status has decreased a bit with the rising fuel costs, it is still a symbol of wealth and strength.

Two, It's perceived as being safer - after all, it's bigger, and heavier than most other things on the road. So you'll just plow through the other cars hardly getting a scratch, right? yeah, right (sarcasm)

Three, some people feel (rightly or wrongly) that they need an SUV. maybe they're in construction and regularly haul stuff around that wouldn't fit in a Prius sized car. or they need to be able to tow a boat, which an engine like the Prius has can't do - so you need something bigger with a bigger, more powerful engine.

and finally four, some people just simply like it better. you'll have various reasons for it - they sit higher, for example. but a car purchase does, in the long run, come down to what you like the best.

The problem is, you can argue till you're blue the benefits of a smaller hybrid car over a hybrid SUV - the SUV owners won't care or change their mind. They have their reasons, and those reasons are good enough for them. These companies are going to work on addressing all of the markets they can with hybrids.

While we would all like GM and such to get in the game with something to rival the Prius, thats not really a market they want to jump right into - it would be very tough. There are currently several hybrid SUV's, but none of them is dominating the way the Prius is. and when you get right down to it, it's not just the Prius... the Civic and Camry are doing very well too. With three major competitors, they would probably prefer proving their hybrid technology to the public through a more open market (SUV's) than the already saturated family sedan market.

 

<div class='quotetop'>QUOTE(pstockley @ Nov 14 2006, 12:53 PM) [snapback]348862[/snapback]</div>

So, let me get this straight... The people you know who own an SUV don't care about fuel economy, and yet if it goes up more they'll care about it so much they'll get a sedan? That really doesn't seem to make much sense... if they didn't care about FE, why move down to a sedan? Simply put, everyone cares about FE to some degree (which your last line implies) - most SUV drivers simply care about other factors a bit more.

I think instead we simply haven't gotten to a point yet where people with SUV's want better FE. they don't see a big enough gap between hybrid and non-hybrid SUV's to justify purchasing a new SUV. Instead, SUV sales have dropped with the high gas prices. Does that mean casual SUV owners are buying smaller cars? some, i'm sure... but i'd be willing to bet that many of them are just waiting for an SUV that has enough FE to be worth it. What would be the point of buying another SUV tomorrow for a nominal gain, if someone announces one with a much larger gain next week? if GM can produce a hybrid SUV with a large enough gap in FE, then it'll be a winner.

I would love to be able to convince all those SUV owners to buy sedans. but the simple utility of having an SUV - the space, size, protection, status - will keep many, many people buying them for a very long time.

 

The problem is you're making big assumptions here that simply have no support... "A decent station wagon would be just as practical for 90% of SUV owners" Was there a polling of SUV owners and why they decided to get an SUV? If so, whats the sample size, and how did you ensure it was a representative sample?

It's true, that if you visit an upper-middle class neighbor hood most people there with SUV's wouldn't need them for much - but what about all those people who actually use the SUV, have it filled with stuff? i'd be willing to bet thats a lot more than 10%

the whole point is to avoid making these assumptions (people will change from SUV's because it won't make sense to have them with high gas prices...) - assumptions that are based on your feelings and the relatively limited input from those around you.

Say you could make a hybrid SUV that increases FE from 15 to 25mpg - You'd reduce your fuel consumption by 40% - so if gas goes up to 4 bucks and you start driving a hybrid SUV, you'd be spending about 1/2 of what you would with the old one - which would be about what you're spending today. Simply saying something over and over again doesn't make it fact - You can't possibly know for certain that SUV's will be almost extinct when gas hits those points - It's much better to keep an open mind and offer alternatives to consumers.

As i've said before, people feel they need SUV's - look at the sales they had in the 90's - even if gas is "cheap", it's still costing you more to drive and SUV than a car - and odds are you paid more for it, too! The US automakers spent tons of money in ads campaigns and such to ensure that the typical American would want an SUV - they aren't going to just ditch all that hard work when it paid off so well. It simply comes down to how business and advertising works. Trying to sell a hybrid sedan right now would be a horrible idea - it would be like you made your own consumer OS and are trying to sell it, competing with Microsoft and Apple. It's just a bad business plan.

 

<div class='quotetop'>QUOTE(pstockley @ Nov 14 2006, 04:11 PM) [snapback]349063[/snapback]</div>

The reason a hybrid sedan from GM won't work is because of the Prius and Civic - it's very difficult to break into a market that already has two extremely strong front runners (not to mention the HyCam, which is growing fast).

And yes, SUV's didn't used to exist. But, times change, and people change. Before, you would have a truck if you needed hauling capacity. Now, you can get an SUV - a cross between the hauling capacity of a truck and the comfort one expects from a sedan. Simply put, through their advertising campaign, the big three managed to convince Americans that they need SUVs, and now they do, for a variety or reasons (all stated above). As for not saving a significant amount on gas... with tax incentives (and they would have their incentives for a while yet, having not maxed out), and the amount you save on gas, it comes down to very competitive numbers. They estimate a 3k premium on hybrids - well, they can get up to a 3k tax credit for buying the hybrid. Suddenly that premium isn't so bad, because the governments paying for it.

From a simple marketing standpoint, it would just be stupid to go in and try direct competition with something as popular as the Prius and Civic hybrids.