40 mpg Prius vs 50 mpg European Diesel cars

The big difference is undoubtedly the turbocharger. Half a bar of boost is fairly standard for consumer gasoline turbos, but the diesel turbo (at least the one in my truck) boosts three times that. It is very much like you describe - foot to the floor - until the turbo gets spinning, but then the power becomes phenomenal.

Mike

. . .

I appreciate the analogy but have a concern that some may be misled into thinking the Prius gears have differential efficiency. The planetary gears are ever so much more efficient yet we've had a couple of skeptics in "Prius Techical Stuff" try to use an SAE paper on differential efficiency to 'prove' the inefficiency of the PDS transmission. We simply pointed them to the DoE paper showing ~1.5-.97 kWh.

You might want to emphasize that internally, the PDS uses a planetary gear system that has much less drag than an ordinary differential. Then there is the ~3 to 1 gear ratio between MG1 and the ICE. It isn't that the analogy is wrong but it can mask subtlties. The skeptics will still ignore these subitles but at least you've tried.

I'll take E-CVT but that is about as far as I can go.

Bob Wilson

Just wait until diesel cars start using bio fuel.

Yandoit Australia

Things only even go wrong at the last moment

J.D.Boatwood

No s*it. That will drive the price of food up.

"...we've had a couple of skeptics in "Prius Techical Stuff" try to use an SAE paper on differential efficiency to 'prove' the inefficiency of the PDS transmission. We simply pointed them to the DoE paper showing ~1.5-.97 kWh."

You mean this one? Fig. 3.8?

Yes.

Bob Wilson

excellent description, thanks! Is this tehcnology unique to Toyota, i.e. patented etc? How does it compare to Honda's or Ford's approach to the hybrid design?

have the same advantages of true motor/generator operation and simplification of the drivetrain, is that right?

Scott wrote:

Ford's approach is so similar that they had to license (some of?) Toyota's patents to avoid infringement. From what I understand, Ford developed it independently, but there was still the infringement issue.

Honda uses a parallel technology (not parallel to Toyota's, but that's the kind of technology) in which both the engine and electric motor are running whenever the car is in motion. (Of course, when the car is stopped, like at a stop light, the engine is off, just like with the Toyotas.) The engine is more powerful, and the electric motor is less powerful. It uses a standard transmission; in fact, you can get the Civic hybrid with a stick shift.

hmm -

I can see your desire to make a DISTINCTION to call attention to a significant technological DIFFERENCE.

But, when it comes to naming things, I think that the rule is that the owner or maker gets to decide - whether children, or dogs, or transmissions.

You make an excellent point that the Prius eCVT is materially, qualitatively, and significantly different from the variable pulley belt drives.

But think about it.

CVT isn't an acronim for "ComplicatedChainBeltVariableRatioTransmission"

CVT means Continuously Variable Transmission.

Perhaps "second generation CVT" would convey more of the wonder of the new Prius. But, it is still a transmission. And, it is still Continuously Variable.

And if Toyota prefers eCVT to "electric differential CVT" or "second generation CVT", they make it, and they (not you) get to name it.

Though, I have to say that you have helped others understand the technology better by your refusal to adopt the given name.

Let's give it a "nick name" (people often do that when they don't like the given name or it doesn't seem appropriate to the object being named).

Let's call it eDCVT2 - awfully long, but indicates the second generation and electronic differential. I don't really care for the "eD" part either...

This is one of the most interesting threads I have seen anywhere recently - so much so I sorted by date and went through again. It is great to learn so much about day-to-day use of hybrids and about batteries and diesel technology.

One thing which is not clear is whether diesel is inherently more expensive to produce than petrol. I suppose the differential depends, in part, on the type of crude and, possibly, dealing with sulphur.

The free gift of hybrids is regenerative braking - the fossil fuels we will continue to waste until this is universal should make us weep.

The thread contains convincing evidence that there is no real barrier to diesel hybrids. My arithmetic suggests that a diesel-powered Prius would do around 35.

What remains unresolved, for me anyway, is whether there is (or needs to be) any significant difference in pollution between petrol/diesel.

I would rather see bio fuel used to heat homes instead of using it for vehicles. Alternatives such as wood, coal, pellets and corn are a pain in the ass unless one never leaves his home for any extended period of time. mark_

There is not really a technical barrier to making a dieseel hybrid function. However, as I mentioned before, there is a cost barrier that consumers may not be willing to pay because there is a premium price for a diesel and a premium price for a hybrid system, so the price of a diesel hybrid could be so high that nobody would purchase it.

The other potential barrier to diesel hybrid sales is that Toyota markets hybrids as a "greener" alternative to conventionally powered vehicles, and many people, especially in the U.S., perceive diesel as a dirtier engine so the number of prospective buyers might be to small to justify development and production costs.

It wasn't always so. Time was that Mercedes charged a premium for the gas engines. If I remember correctly (always a chancy thing), the -D was, for some years, the bargain basement Mercedes and a gasoline engine was $3K upgrade (might have brought along more features).

I can't think of any particular reason why a diesel should be significantly more expensive than a gas engine - at least not any intrinsic reason. Doesn't it have a similar part-count and similar fabrication methods? Those two items should pretty much determine the cost to produce, shouldn't they? Fixed costs divided by unit production make a difference. If the diesels are low-volume production, the fixed-cost per unit would be higher but I doubt this would justify a huge price difference in the motors. Other supply chain overhead might also drive up the cost of the lower-volume engine a bit.

I think that the lower volume of diesel engines for many automotive applications is what drives up the cost, plus the additional battery capacity. The mechanical fuel injectors used to be very expensive, modern electronic ones are probably in line with the cost of a gas engine.

Could be because the diesel engine is in fact dirtier than the gasoline models you mention? For example, you cannot buy a new VW TDI diesel in my state, because the emissions are so bad.

(EPA air pollution scores are based on 1=worst, 10¾st. For the Maximum allowed grams per mile Emission limits at full useful life (100,000-120,000 miles), see:

NOx=Oxides of Nitrogen: Compounds containing nitrogen and oxygen; they combine with hydrocarbons in the sunlight to form smog

NMOG=Non-Methane Organic Compounds: Compounds containing carbon; they combine with NOx in the sunlight to form smog

COÊrbon Monoxide: A colorless, odorless, poisonous gas

PM=Particulate Matter: Tiny particles of solid matter that lodge in the lungs and deposit on buildings

HCHO=Formaldehyde: A lung irritant and carcinogen

So yes, I would say that the diesels are dirtier (more than 2x for HCHO, 20x for NOx) than the Toyota hybrids, because they are.

Dodge Sprinter is selling in every states.

UPS/Fedex Spr=>

=>Could be because the diesel engine is in fact dirtier than the gasoline =>models you mention? For example, you cannot buy a new VW TDI diesel in =>my state, because the emissions are so bad. =>

=>2006 VW Golf TDI, EPA air pollution score of 1, LEV. Not sold in CA or =>the New England states. =>

=>2006 VW New Beetle TDI, EPA air pollution score of 1, BIN9. Not sold =>in CA or the New England states. =>

=>2006 Toyota Highlander Hybrid, EPA air pollution score of 8, BIN3, not =>sold in CA or the New England states, or for the CA emission version is =>an air pollution score of 9, SULEV II. =>

=>2006 Toyota Highlander Hybrid, EPA air pollution score of 8, BIN3, not =>sold in CA or the New England states, or for the CA emission version is =>an air pollution score of 9.5, SULEV II. =>

=>(fueleconomy.gov doesn't have the 2007 model years available yet, =>otherwise I would've included the available 2007 Toyota Camry hybrid. =>no score was listed for the VW Jetta TDI.) =>

=>(EPA air pollution scores are based on 1=worst, 10¾st. For the =>Maximum allowed grams per mile Emission limits at full useful life =>(100,000-120,000 miles), see: =>

=>To note the limits for the non-CA emission states (listed as maximum =>grams per mile): =>

=>NOx=Oxides of Nitrogen: Compounds containing nitrogen and oxygen; they =>combine with hydrocarbons in the sunlight to form smog =>1 = 0.6 =>8 = 0.03 =>

=>NMOG=Non-Methane Organic Compounds: Compounds containing carbon; they =>combine with NOx in the sunlight to form smog =>1 = 0.280 =>8 = 0.055 =>

=>COÊrbon Monoxide: A colorless, odorless, poisonous gas =>1 = 6.4 =>8 = 2.1 =>

=>PM=Particulate Matter: Tiny particles of solid matter that lodge in the =>lungs and deposit on buildings =>1 = 0.08 =>8 = 0.01 =>

=>HCHO=Formaldehyde: A lung irritant and carcinogen =>1 = 0.027 =>8 = 0.011 =>

=>

=>So yes, I would say that the diesels are dirtier (more than 2x for =>HCHO, 20x for NOx) than the Toyota hybrids, because they are.

"I can't think of any particular reason why a diesel should be significantly more expensive than a gas engine - at least not any intrinsic reason."

The high compression ratios are the main reason. Everything is hunkier and heavier built, from the pistons to the connecting rods and the crankshaft, bearings and crankcase, and the fuel metering system and injectors must also accommodate high pressures and temperatures and vibration. Bearings and rings tend to be more sophisticated in their design, requiring more machining and additional parts, and the lubrication system is more sophisticated, with even the old VW Rabbit having piston-cooling oil showers. More noise-deadening padding and baffling must be employed. And since the ignition is by compression rather than spark, the engines are less amenable to electronic control, reducing the beneficial impact of one of the biggest savings drivers in automotive design today. Emissions are more difficult to clean up, too. Despite what you've read on this thread, modern European automotive diesels are plenty stinky, though I admit they are improved.

I wonder what your neighbours would think of you burning old fish & chip oil.

I think you are wrong. Both diesel and petrol engines are built to the same tolerances and, though engine management for diesels is even more sophisticated than petrol, the impact on cost is negligible.

The only convincing reason I know of for diesel engines being more expensive is that a much smaller number of them are made. Thus the development costs must be recovered from a smaller throughput.

The things you mention might call for a few extra grams of steel - chickenfeed.

If a diesel system is produced in similar numbers to petrol you will find little difference in cost per engine.

And I have a theory that diesel engines last longer - because their fuel has some lubricating properties, unlike petrol.

Thus a mass-produced diesel might well yield a whole of life cost less than the petrol equivalent.