12-14-2010, 06:52 AM
|
#231 (permalink)
|
Master EcoModder
Join Date: Jul 2010
Location: Belgium
Posts: 4,683
Thanks: 178
Thanked 652 Times in 516 Posts
|
Quote:
Originally Posted by NeilBlanchard
Do diesels have Start/Stop tech?
|
Why not ?
In Europe, it's been on small diesel Citroens and the 3L VW Lupo and Audi A2 since about the time the 1st generation Insight popped up.
10 years on, it's more common on diesels than it is on gas engined cars in the EU market.
Quote:
Do the EPA rating for diesels take into account the higher BTU's per gallon of diesel?
|
Dunno, but on this side of the pond the trend is towards using grams of CO2 per km (which accounts for the energy density) rather than using L/100km or mpg (which does not).
__________________
Strayed to the Dark Diesel Side
|
|
|
The Following User Says Thank You to euromodder For This Useful Post:
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
12-14-2010, 10:05 AM
|
#232 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
|
Hi,
Quote:
Originally Posted by autoteach
So, if the EPA uses mpg for both, but uses mpge for electric, one could conclude that they do not account for the energy density difference. That is their efficiency at constant operation, not using engine stop/start tech.
|
That's what I figured. According to the X-Prize MPGe spreadsheet, diesel has to be multiplied by 0.9 to be MPGe; or 1 gallon of diesel = 1.12 gallons of gasoline. The Wikipedia page linked earlier says diesel MPG needs to be multiplied by 0.83660305694757009 (!!) to be MPGe.
That makes it seem like most of the FE for diesels is due to the higher energy level of diesel itself, and only a little is because the engines are more efficient.
|
|
|
12-14-2010, 11:20 AM
|
#233 (permalink)
|
Building the future! :-)
Join Date: May 2008
Location: orlando
Posts: 177
Thanks: 2
Thanked 12 Times in 11 Posts
|
I had a facinating conversation with a guy yesterday who built himself a turbo diesel snowblower (of all things)
He stuck a turbo from a Saab car on it and said a few telling things...
1) it no blows snow WAY further and never EVER bogs down.
2) It burns less fuel overall then before even with the increased power.
3) the black smoke these little diesels are known for is for the most part, gone.
I know how unscientific this is, but I have a keen interest given my use of one of these 10hp diesels on Belaero. Looks like I can get another HP or 2, lower my bsfc and pollute a bit less with the use of a little turbo.
Anyone tinker in this area?
|
|
|
12-14-2010, 01:27 PM
|
#234 (permalink)
|
needs more cowbell
Join Date: Feb 2008
Location: ÿ
Posts: 5,038
Thanks: 158
Thanked 269 Times in 212 Posts
|
Quote:
Originally Posted by NeilBlanchard
...
That makes it seem like most of the FE for diesels is due to the higher energy level of diesel itself, and only a little is because the engines are more efficient.
|
boo! This thread is replete with the details of why this is not the case, you are not paying attention, I'm done typing.
__________________
WINDMILLS DO NOT WORK THAT WAY!!!
|
|
|
12-14-2010, 04:29 PM
|
#235 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
|
2009 VW TDI has 41MPG Combined EPA rating.
2009 Jetta TDI's Mediocre EPA Rating Not Whole Story
41MPG x 0.9 = 36.9MPGe
Where's the advantage of 42% vs 25% efficiency?
|
|
|
12-14-2010, 05:27 PM
|
#236 (permalink)
|
Master EcoModder
Join Date: Sep 2010
Location: Denver, CO
Posts: 1,300
Thanks: 315
Thanked 179 Times in 138 Posts
|
Quote:
Originally Posted by NeilBlanchard
|
The Jetta TDI is rated 30/42, the equivalent gasser is rated 23/30. There is your advantage.
__________________
I'm not coasting, I'm shifting slowly.
|
|
|
12-14-2010, 10:30 PM
|
#237 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
|
Point taken -- it's funny, but my 1987 Golf 1.8L got about 36MPG. And it lasted 14 years and ~217,000 miles; the engine ran wonderfully to the end. It died of rusty chassis...
|
|
|
12-14-2010, 10:37 PM
|
#238 (permalink)
|
Master EcoModder
Join Date: Apr 2010
Location: belgium, wi
Posts: 262
Bus - '94 Ford School Bus huge Stupid - '01 Chevy Blazer LS 90 day: 21.38 mpg (US) hawk - '00 Honda Superhawk
Thanks: 2
Thanked 24 Times in 19 Posts
|
Neil, If you want to believe the EPA cycle on this one, you can and I wont. I have ridden in and driven TDI jetta's and knwo that this information is completely wrong. Steady state driving on the highway, on the flat, and city yields much better FE than the EPA shows. This is not accurate and my friend and I do not hypermile. But, as usual, whatever you want to believe, read, or not read, and use as your metric, go ahead.
|
|
|
12-15-2010, 12:55 AM
|
#239 (permalink)
|
Master EcoModder
Join Date: Jul 2008
Location: Silly-Con Valley
Posts: 1,479
Thanks: 201
Thanked 262 Times in 199 Posts
|
Quote:
Originally Posted by NeilBlanchard
Point taken -- it's funny, but my 1987 Golf 1.8L got about 36MPG. And it lasted 14 years and ~217,000 miles; the engine ran wonderfully to the end. It died of rusty chassis...
|
Yes, and Honda CRX HFs routinely get 45-50 MPG and last at least a couple of hundred thousand miles. And Geo Metro XFIs tend to get even better MPG and last a decent while as well.
Note that none of them would pass current emissions or collision testing, nor do they have sixty-seven cup holders and lots of head, leg, shoulder room, automatic climate control, and on and on and on.
Apples and oranges, my friend.
-soD
|
|
|
12-15-2010, 11:58 AM
|
#240 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
|
I get the EPA isn't the real world. So, using the adjusted numbers of the 2009 VW Jetta TDI manual vs the 2009 VW Jetta manual:
30 city / 41 hwy = 27MPGe / 36.9MPGe
21 city / 31 hwy
So the actual difference is about 16% on the highway (and nearly 33% in the City?!). That does jibe with the efficiency of the engines. So, in theory if the engine could manage to be 54% efficient instead of ~42% that the TDI or 25% of the gasoline engine -- then the highway mileage would be 40-41.3MPGe. Not too great, really.
Keep in mind, that the Volt is rated at 93MPGe in EV mode, 60MPGe combo mode, and 37MPG gas only. The Leaf is 99MPGe Combined. And the 2010 Prius is 50MPG Combined -- the plugin will be better.
|
|
|
|