New Accord Rear Window Visibility ? And, Legacy vs. Accords Opinions ?

"jim beam" wrote

I remember one time in the late 70's.... I didn't pay attention since then, though.

Back in the day I thought it was tax differences only.

But diesel has more BTU value than gasoline, "should" cost a little more per gallon, "should" give somewhat better mileage.

If it's that much more expensive now, I presume that's mostly tax differences now cutting the other way?

J.

they don't price on btu's unfortunately. otherwise we'd see prices go down for winter blends and ethanol inclusion. better mileage on diesel comes not just from btu's [which are now reduced as part of the low sulfur rort], but also the inherently better thermodynamics of diesels.

it used to be priced according to what they wanted to sell. back when gasoline trucks were more common and before modern refinery catalysis, diesel was an over-supplied fraction of oil, so it was lower priced to encourage use. now, catalysis means refiners are no longer hostage to the distillation fraction proportions, and they can make virtually whatever they want - all gas or all diesel. there's no technical reason for pricing differences any more.

and you can look up tax differences, but iirc, they're minimal.

Yes, meant to mention, they don't water the diesel with ethanol!

But the inherent better thermodynamics used to come at a premium in engine price and weight per displacement, but maybe technology has reduced that?

J.

yup, the "price" is still there - it's for compression loads in fuel, combustion compression, and to a lesser extent thermal loads. displacement "price" is less of an issue on turbo diesels.

but the good modern turbodiesels are really good. compare their output/weight with some of the detroit v8's and you'll be pleasantly surprised.

further to that, all the "price" concerns tens to fade when considering where diesels are going today:

note the trademark diesel high pressure injector lines.

I'm vaguely aware of the new high-performance diesels mostly in Europe, I guess VW is offering at least one or two models here, anyone else?

Would they make a diesel-electric car any more practical - where the diesel engine runs most of the time but just to turn a generator, actual wheel drive is always 100% electric?

Or maybe drop one into a Volt?

J.

dose anyone remember whe gasoline was 25 cents a gallon?

And you got free maps and drinking glasses, and your windshield cleaned, too.

J.

in addition to the peugeot in that article [which would include citroen] the bmw and mercedes high performance diesels are quite good.

but the majority of the action is in the smaller sector. they have vehicle tax brackets in europe based on engine capacity. iirc, one of them is for diesels below 2.0l. hence that's where there's most attention. and why frod, g.m. and fiat all have euro-diesels that qualify. [and why i get torqued that these "big three", who could for ZERO DEVELOPMENT COST, OFF THE SHELF, won't bring them over here.]

you can lose efficiency doing that. it makes sense on a loco to get the high torque from zero and to get transmission reliability, but for a car, it's overkill.

the chinese component manufacturers of the volt wouldn't appreciate that.

A matched motor-generator is pretty efficient, and with solid-state power electronics you can put a few batteries in the circuit and still have systemic efficiency. And you gain more keeping the engine at peak RPM - though I guess a CVT is helpful there too.

Still, it might be trendy, and more efficient than the Prius-style hybridization. I suppose not cheaper, though. I still think from the description the Fisker Karma may be 100% electric drive, but it ain't cheap.

J.

right - batteries will be the essential differentiator.

the other thing is driveability. one of the things about the prius is the starting of the gas engine, especially when pulling away from the lights. while not terrible, i wouldn't exactly call it smooth. with the compression of a diesel, that's going to be much more noticeable.

On 1/6/2013 12:51 PM, Stewart wrote:> depending on the delta between the two fuels).

Why not? My Civic hybrid is is approaching 11 years old (240,000 km) and still giving good mileage. It has averaged ~46 MPG (US) or 5 L/100km) over that time. I never expected to recoup the "hybrid premium" when I bought it, but it has done better than than and paid off most it not all of the luxury premium. (The 2013 Civic hybrid, was fitted out with the fancy extras that came on the Acura EL).