That I would believe, the engine doesn't even warm up in 4 miles. Still, it's cherry picking data because the average commute in the US is almost a half hour.
Cold air does a few things:
-More aerodynamic resistance because the air in denser and more viscous
-Colder tires (and winter tires) have a higher rolling resistance
-Some components operate less efficiently in the cold
Colder air does improve the power output of the engine at a given throttle position, but only because more air, and thus more fuel, is consumed. This does not improve fuel economy as it is more than offset by the deleterious effects above and the other effects outlined in the chart Eug posted.
[1]So having a lower Cd in the first place will help with the first point? Because not having to pass air over a radiator allows for some pretty slick car designs. Tesla is down to .24, and there have been some experimental vehicles the surpass that, but NHTSA has surely gotten in the way to make sure the texting plebs don't die too easily.
[2]So when the air gets colder, we have less pumping losses, but via stoichiometry, the denser charge needs more fuel anyway, so the other variables play in to produce a net loss in fuel economy?
[3]Meanwhile, a 3phase electric motor barely cares about the tiny temperature delta that is global climate. Batteries are another story, but it has always been the battery which is the weakest link of an electric car system.
Tesla is down to .24,
Batteries are another story, but it has always been the battery which is the weakest link of an electric car system.
My 16 year old Passat had .27 cd WITH radiator inlets/grills etc.
There is nothing impressive about .24.
That was the case 100 years ago.....and will be the case FOREVER.
See: http://en.wikipedia.org/wiki/Automobile_drag_coefficient
.24 is good enough for 4th best production car ever, and I think 2nd or 3rd best current production car. It is impressive given that the S actually has style. The field is pretty flat in terms of Cd, making a .01 or 0.02 change is a big deal.
Aren't we looking me for Cd*A then Cd in these comparisons? I mean having a low Cd is definitely a huge part of the objective, but reducing the total area the drag is applied over matters a lot too.
I imagine the frontal area of an S550 is larger than a Model S.
I imagine the frontal area of an S550 is larger than a Model S.
For practical applications, Cd*A is the right number to look at.
For design comparison it's handy to look at Cd along because A is influenced by the vehicle's application, intended market's safety requirements, and other factors that are not usually intrinsic to good aerodynamic design practices.
[3] The batteries do care very much about temperature (reaction kinetics can be very sensitive to temperature changes) and certainly dominate any effect of temperature on the motors. However, the electrical conductivity of the (presumably) copper windings in the motor will change with temperature, which will effect the motor's power and efficiency. I know it's not a huge change, but it is a change!
Thanks for answering the previous questions and trying to shut down vdub's ignorance. I looked up the drag equation, and realized I was completely misunderstanding what was implied in the frontal area part of Cd*A, assuming it was only the nose and most forward parts of the front plane.
I see Midwayman's point, because the Model S has an actual back seat, where the C class is a bit more cramped.
This part I do know, as I am an electrician apprentice, and the resistance of copper increases with higher temperatures. By Ohm's law, higher resistance at the same voltage means less current, and therefore less power. That said, the ambient temperature is probably of little consequence after a short amount of time, compared to eddy currents heating up the windings of the motors.
They are three phase AC motors, according to a show I watched about them. Which is cool they went with a tried and true motor technology, but I have to wonder why it wasn't all out DC brushless, except for costs, or developing a brushless motor to deliver that much power.
And vdub, the fact that you use "forever" in your post accentuates that you are an ignorant small-minded person.
So having a lower Cd in the first place will help with the first point? Because not having to pass air over a radiator allows for some pretty slick car designs. Tesla is down to .24, and there have been some experimental vehicles the surpass that, but NHTSA has surely gotten in the way to make sure the texting plebs don't die too easily.
So when the air gets colder, we have less pumping losses, but via stoichiometry, the denser charge needs more fuel anyway, so the other variables play in to produce a net loss in fuel economy?
Meanwhile, a 3phase electric motor barely cares about the tiny temperature delta that is global climate. Batteries are another story, but it has always been the battery which is the weakest link of an electric car system.
Brushless DC motors and three-phase motors are not all that different, in fact. I think that what most EVs use today at PMAC motors which also happen to be 3-phase. They receive a sine wave (three, actually) from the inverter. Brushless DC motors get a square wave. I think they take an efficiency hit for that, too. I think the 3 phase PMAC motor design is the best one for this application.
Other than that the stator and rotor are flipped? The permanent magnet motors are usually more efficient, but they are not cheap. Unfortunately, we are in an era where cheap is the golden rule, and people get pissy when they cheap out and the product/service does not exceed their expectation.
The two new motors together reduce total rare-earth content from 3.2 kg (7 lb) on the Gen-1 system to 1.2 kg (2.6 lb)
That is really impressive.
That first 1.3 miles is the worst. Short commutes will bring down any average, especially in winter.
Is it?
Simple math.
380 mile/9.3 gallons = 40.86 MPG (this is NOT counting electric energy either, which would lower that #)
Cars are doing that TODAY without extra electronics/electric batteries and extra motors.
Why all the continued crankiness and butt-hurt?
That makes little sense, as some people would not use the heat at all, and others would preheat the cabin before unplugging the vehicle.I would love to see "Electric car ranges" with heat on full entire time.
We all know whenever it comes to electric heat or heating ANYTHING with electricity, we are talking the least efficient and costly out of ALL of the energy options we have today.
2016 Cadillac ELR gets more power, $9,000 price drop
Cadillac has announced a series of updates to the ELR for 2016 that promises to make the plug-in hybrid luxury coupe a more desirable proposition. Perhaps chief among them is a price drop of $9,005 compared to the slow-selling 2014 model. The news follows an announcement yesterday that the Chevy Spark would get a $1,500 price drop.
...
One big upgrade on the performance front is a 25-percent boost in output from the hybrid powertrain that marries a pair of electric motors to a 1.4-liter inline-four gasoline-burning generator. The increase is said to be enough to drop 1.5 seconds off the 0-60 time, now quoted at 6.4 seconds. It'll travel for up to 39 miles on electric mode alone, but with the generator spooled up will go up to 330 miles before needing to stop.
What on earth are you smoking and where can I get some? I was commenting on the reduction in rare-earth materials used in the drive motor(s) by over 60%. That is an impressive feat.
But let's talk about the totally different thing you brought up.
First, 41MPG is pretty darn good for a car as large as the Volt. There aren't many cars rated near there, and few that are the size of the Volt. Also, they're generally hybrids.
Second, the first gen volt was rated around 37mpg in gasoline-only mode. I would expect this number to only increase.
Third, fuel tanks are usually sized with some reserve compared to their rated range, typically 1-2 gallons. And sure, let's knock off the electric range (38mi from the previous generation, no other numbers to use). Using your crayola math we would get:
(380mi-38mi)/(9.3-2gal)=46.8mpg, which is very good for the large side of compact cars, especially those that aren't stripped-down econo boxes.
Consider that 80% of gen-1 driving was done in EV range (also in the article) and you realize that the Volt is an EV that can be taken on long car trips. That is to say it's the car that many people say they want.
Why all the continued crankiness and butt-hurt?
We have a gen 1 volt and I avg. over 100 mpg not counting electric. (from nov-april. i expect this number to be closer to 200 by the end of the summer) I pre-heat and with a bit of heat on during the drive get around 25 miles electric in the winter. i spend about 30 dollars a month extra on electricity with 52 mile commute. filling up once every few weeks for 20 bucks is sure nice too.