Characteristics Jetta vs Prius people

Personal experience.
A Prius owner in my hometown once told me it could get 50MPG constantly, while I've already managed to get the very same mileage with a Corolla powered by the archaic 2C engine in a trip to Uruguay (sure, had to do some EOC and shut the engine off at traffic lights), and the Corolla didn't have an electric water pump, electric power steering or an all-electric air-conditioneer, having still to take more power from the engine to move the power steering pump and the air-conditioneer compressor, not to get into its aerodynamic disadvantage over the Prius.

 

Some Diesel Hybrid talking points (I do not know that these are facts, but I think they are, feel free to enlighten me)

The pseudo Atkinson cycle engine trades raw power per displacement for near Diesel efficiency.
Peak Thermal Efficiency
Diesel 40%
Atkinson 37%
Otto 25%

However, like the Otto cycle, efficiency falls off at low loads and idle as you need to maintain the stoichiometric ratio, and so need to close the throttle introducing pumping losses. Since the Diesel does not need to maintain any given fuel/air ratio, its low load efficiency is greater. A potential Diesel Hybrid would not need to switch to battery only propulsion to hide poor efficiency.

Once warm, both the Otto and Atkinson Cycle engine are easy to start, while a Diesel is much harder to start. A Diesel Hybrid will need a much larger M/G1 and a larger HV Battery to power it, if it did Start/Stop like a Prius.

This combination of being hard to start and having little gain from not running the Diesel at low loads will mean that just slapping a diesel engine into an existing hybrid HSD is ill advised, you need to think of what 'weaknesses' a Diesel has and how to use electric motors to hide those 'flaws'.

Due to low speed inefficiencies, the M/G2 in a Prius is geared to add torque at low speeds, one diesel 'weakness' is a reluctance to change RPM, potentially the M/G2 of a Diesel would be geared to allow the diesel engine to maintain a given RPM and provide momentary power increases electrically. A Diesel engine is already strong at low speed torque so the existing Prius M/G2 has would have no weakness to hide.

When stressed a turbocharger builds up a lot of heat, so a cool down period is advised before turning off the coolant supply (most often engine oil, sometimes aided by engine coolant) Very few Turbocharged engine use Start/Stop technology of any sort. A turbocharged Hybrid, Gas or Diesel, should have a high voltage electric cooling system to prevent coking.

I am sure there are other design issues awaiting some poor engineer whose boss thinks it would be easy to make a Diesel Hybrid.

 

I am not positive that having heard someone make a claim is actually experiencing that claim. In the legal profession it is called hearsay and is frowned upon. What I suspect he said that you did not hear is that he could average 50 MPG, not that it was his peak MPG. (my theorizing is even less approved legally)

If your car got 50 MPG for the life of the car, not one trip, then indeed you had a winner of a car! I frequently get 50 MPG at a constant 60 MPH in my fully loaded Prius station wagon, but as you can see below, my lifetime average is just over 40 MPG. Prius Liftback owners may average 50 MPG, Prius PHV owners over 60 MPG average.

 

When we are talking peak efficiency
vw tdi - 42%
best turbo diesel (much bigger) 50%
toyota atkinson (Lexus ISh) 38.5%

Toyota claims 42% in the lab for atkinson. Otto is no longer otto with variable lift an otto engine like skyativ can run in the atkinson cycle when it wants too, so theoretically the same peak efficiency.

A diesel ice car is heavier, more expensive, and requires more maintenance if you comply with euro 6 or EPA regulations. In a car the size of a camry or smaller that is a bad trade off. What you gain in highway efficiency, you lose in city efficiency because of the weight. In larger vehicles diesel hybrids may make sense. When you get to 18 wheel trucks, the tradeoff is clearly in favor of diesel, and the battery is much bigger, but plug-in diesel medium and heavy trucks make a great deal of sense in polluted cities like LA, Houston, Pittsburgh as they can be made to pollute much less. On those trucks going across the country the battery doesn't do that much good.

 

Altough the thermal management of a Diesel engine in-between idle shut-offs, turbocharger bearings being a critical point, and the exhaust aftertreatment being more difficult and expensive, technology is improving.

I see there's still a mutual hatred among dieselheads and the hybrid users, but apart from some douchebags in both sides we're all basically on the same boat. I'm into Diesels because of their higher adaptability to the usage of vegetable oils as fuel, which I can get at lower costs than gasoline or regular Diesel fuel, and also due to their resilience in severe environmental conditions (altough I must admit it applies better to old-school Diesels), and I'm against those posers who get those smoke-switches to annoy other drivers or pedestrians. Bashing each other because of the different technical features of the cars like a bunch of juveniles is ridiculous.

He told me his Prius was getting 50MPG constantly, not just inner-city but also in highway. And he was not a hypermiler.

 

If you have some data that supports your view that your main priority is not a tiny minority of Prius owners, let's see them.

In surveys I have seen, the main reasons for picking a Prius (in no particular order) have been:

• Tech toy
• Environment
• $

OTOH, a distinct "cut_oil_imports" crowd seems to exist within the GM Volt universe. Still a tiny group, but they make a fair amount of noise.

 

This is a quote from Fred's TDI where a member asked if it would be better to buy a TDI or a hybrid.

"One last item to consider, if "Greeness" has any bearing on the thought processes. Hybrid does not equal green. Diesels are far "greener" than any hybrid, since the entire car can be recycled at the end of its useful life. Hybrid vehicles cannot, due to the batteries and how they are made. The batteries must be taken apart and the non recyclables disposed of properly. Just food for thought."

 

Actually that has not proven to be true.
Replacing Prius batteries can be good for the environment... and sales

RAL

 

I don't doubt it is for some people. It certainly was a leading reason for me.

The TDI people, however, do not seem to be able to calculate any half-accurate result and instead just spout FUD. About as stupid a group overall as the Volt advocates.

 

Bob, he was calling the pious, FUD spouting, vocal minority of both camps 'douchebags'. A video of such a hybrid one accosting a diesel truck driver, who also owned a Prius, at a gas station was posted here not so long ago. There are those that believe a new Jetta TDI driven off the lot will spew clouds of smoke. If not do to a misunderstanding, your post would be borderline.

This doesn't mean that something won't fail down the line with long term ethanol use. The 1.4L in the Sonic is actually a flex fuel engine. Doesn't have the E85 trim maps or a alcohol sensor. And 12 inches of fuel line isn't compatible. It's possible to go flex fuel with a tune and a sensor pulled from a Buick. It is highly recommended to replace that line. The person that went through the effort had the shop refuse to install the sensor without replacing that line. A line GM oks for E15.

Toyota has to offer a Prius that can run higher ethanol content in Brazil. IIRC, most cars there are E20 to E100 flexible. E20 might be the closest to pure gasoline you can get in some areas. And Toyota will use parts compatible with the ethanol content there. Would you use a gas/ethanol blend in your plane? If not, why do you think its safe to exceed Toyota's E10 limit for the Prius?

When it comes to biofuels and diesels vs. ethanol and gassers, the diesels are at an advantage. The engines themselves don't need modification. As long as fuel could flow, the engine would run. Plenty of people still dump old motor oil and transmission fluid into their old diesels. Vegetable oils only have a flow issue. The tank might need to be heated, and most use duel fuel systems to start on diesel until the engine is warm and flush out the VO before shut off.

Biodiesel is corrosive, but B100 resistant fuel lines have been used since the mid '90s. The issue with today's diesels isn't the engine, it's the emission controls, namely the DPF. The cheap, and thus common, way to regenerate the DPF is to inject some fuel into the cylinder on the exhaust stroke. The problem arises because biodiesel is less volatile than diesel, and some gets left behind in the cylinder. Where it collects on the walls, possibly gunking things up, and works it way into the oil, thinning it out. This is why the European diesels here are limited to B5.

Ford and GM allow B25 in theirs. I'm not positive, but they likely inject the fuel for a regen cycle directly into the exhaust. The B25 is mostly do to the fact that it is quite easy to make biodiesel at home. Which means it is quite easy for some lazy homebrewer to be dumping glycerol, soap, or water into their fuel tank.

Note I specified ethanol before. Butanol can be made renewably, and depending on the source usable up to 85% or higher in an unmodified gasoline car.

 

Just sticking 2 useless cents in here - I'm just looking for a new car, spending a lot of time to research Prius at the momnet. I've been referred by friends to Jetta and other TDI's, but now coming to understand their views are based on some amount of FUD as seen here.

And RE the "eco-unfriendly" battery creation/disposal concepts, I'm also hearing a Lot of that FUD from all over. People really believe that stuff. The Toyota videos are good as are confirming independent sources, but more of this info (and solid evidence) needs to get out there into the public or it's going to be a constant thorn in the side of Toyota and their supporters.


Video on Toyota plant in Japan and complete life cycle


Video on Toyota recycling system


Autoblog short article - confirmation that batteries aren't scrapped, they're recycled

 

Don't forget the $10,000 batteries.

 

You may not start out with that but some people do.