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261 MPG Volkswagen XL1 diesel plug-in hybrid (treehugger.com)
41 points by MikeCapone on Feb 21, 2013 | hide | past | favorite | 45 comments



I like my Jetta. I'll probably get another one when I look to replace it. I am leaning toward a TDI. If VW made a Diesel Hybrid it would probably be a "Shut up and take my money" moment.

What I'm saying is I would really like VW to come out with a Diesel Hybrid. Given how they push their diesel cars as 'Clean Diesel' I'm surprised they haven't already released one.


I bought a 2012 Golf TDI a few months ago. I really like the diesel engine (that pull you feel when accelerating up a hill is exhilarating). It was the only car I drove (in my price range) that actually made me enjoy the experience.

A few drawbacks, though:

* The DSG transmission has a weird bug that causes some lurching at low speeds, like the transmission suddenly up & down-shifts repeatedly. Many drivers report this same issue but my dealership won't acknowledge the problem. They have been unable to reproduce it. I can reproduce it every morning when leaving the parking garage.

* Diesel is an oily fuel that does not evaporate. Most pumps I use have a nice layer of diesel coating the handle that never goes away. I now have to wash my hands after every fueling.

* The TDI engine adds a bunch to the price of the car. Hopefully the claims that the engine needs less maintenance will be true and will help offset the initial extra cost. I easily get 32 mpg with combined city and brief highway every day. On long trips it's easy to get up to 42-46 mpg, so that should help offset the extra cost too.

* Diesel is currently more expensive than gasoline, but I'm betting on that changing in the future. Diesel powers industry which should have a more constant and predictable demand curve. It shouldn't be subject to the drastic price fluctuations that gasoline sees. We'll see how that works out.


The general consensus (at least in the UK) seems to be that modern diesel cars have a potential to be ruinously expensive when they go wrong, which they are somewhat more likely to do on account of the high-precision parts operating at high temperatures and pressures in order to provide something other than the soggy performance of yore. (The emissions stuff also doesn't help.) So you have to drive a lot of miles, to guarantee a substantial saving on fuel, before buying one becomes +EV. This has been somewhat borne out by my observations. Pre-Euro IV diesels seem to be a bit better. I don't like to sound like I'm pissing on people's parade but the reputation diesel cars have for being reliable doesn't seem to be quite so true these days.

The savings don't add up to a great deal compared to the cost of the car either ;) - the savings on fuel cover repairs and routine servicing on my second-hand diesel car, which works for me, but it doesn't actually add up to a huge amount per year. Maybe around £500, or $750. This is at UK fuel prices too, currently $8.20/US gallon for diesel and $7.80/US gallon for petrol, and I mainly drive my car round town, where diesels seem to be comparatively more efficient than petrol cars (though obviously it's not a great thing for either).

(Of course, if my car requires nothing doing one year, or less than £500 of stuff, then I'm quids in! - but this hasn't happened yet. Hmm... maybe next year?)


I drive a 30 year old Mercedes diesel. It runs like a clock. It cost me $3,000 when I bought it 10 years ago. It's never had a major problem. I highly recommend them.


> Most pumps I use have a nice layer of diesel coating the handle that never goes away. I now have to wash my hands after every fueling.

Disposable nitrile gloves.


I had a similar thought.

When I have to fill up the portable tank for the lawn mower, I take some disposable latex gloves along. (Exposure is a short enough period of time that this seems to provide adequate protection for gasoline, at least based on the "smell test".)

It's slightly wasteful, I suppose. OTOH, a random piece of plastic packaging discarded may be more wasteful. And I'd prefer to keep that stuff out of my innards. And, since gas cans in the U.S. have all been redesigned to store the pouring spout internally, I haven't found one that does not force me to get gasoline all over my hands when I use it.

On sale, the latex gloves are something like US$3.50 for a box of 50 (25 pair). I think I've seen nitrile gloves for not a lot more.


As noted by stcredzero, nitrile rubber performs much better when handling oil-based products.

Although its physical and chemical properties vary depending on the polymer’s composition of nitrile, this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals (the more nitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the material).

http://en.wikipedia.org/wiki/Nitrile_rubber


The nitrile gloves are worth it. Petroleum products don't wreck them nearly as quickly as with latex.


Until late last year (when I totalled it), I had a 2009 Golf TDi which I _adored_. As you mentioned, the powerful pull of the diesel inspired many a late night ride. IMHO the TDi is the perfect combination of power, fuel economy and driving fun. My overall average fuel economy was ~5.5 L/100 km.

Sorry to hear about your issues with the DSG. It Just Worked for me. The 1-2 and 2-3 shifts were flawless and I could barely feel the loss in power as it shifted. Until the last few months before my accident, I never used the manual mode. But I discovered that switching to manual mode and leaving it in 4th gear kept the diesel in the perfect power range (3500-4000 rpm) for fun drives through the local mountains of northern Sydney. And even with the harder driving, I would still end up with an average of about 6.5-7 L/100km. Very, very impressive!

Here in Sydney, diesel is a bit more expensive than petrol (0.05-0.10 AUD/L). But I was shocked how much more diesel cost on a trip back to the US over Christmas. Differences of 1 USD were not uncommon. I still think that long-term even with that price difference the diesel would work out better.

The only draw back about the TDi was the lack of immediate power from a stop, while the turbo spinned up. I had forgotten what it was like to move immediately until I rented a petrol car (2012 Audi A1 - and clearly inferior to the VW Golf) for 6 weeks. You can't have everything I guess. :)


What's really annoying is driving a Golf TDI in an area where everyone expects you to speed up quickly from a red light. We're talking about a second or two of difference, yet people honk, tailgate, and otherwise behave as though there is something wrong with you around where I live.

Not that I personally care about appeasing such people.


As a gas-hybrid owner, I always thought that a diesel-hybrid would be the ultimate combo - a flat-torque-curve of electric motor for snappy starts and the thrumming late-curve power of a diesel.


Just for easier comparison, 1.00USD/Gallon is about 0.26USD/Litre; Still a fair bit more, but perhaps not shockingly so?


In the US, diesel is more heavily taxed than gas [1], in no small part because it's primarily used commercially, so higher taxes are met with less popular dismay.

Of course, taxes per mile make for a more interesting comparison than taxes per gallon, so the higher per-gallon tax isn't necessarily the best metric to consider. But the higher taxation does mean that fluctuations in the price of oil has less of an impact percentage-wise.

[1] http://en.m.wikipedia.org/wiki/Fuel_taxes_in_the_United_Stat...


> * The DSG transmission has a weird bug that causes some lurching at low speeds, like the transmission suddenly up & down-shifts repeatedly. Many drivers report this same issue but my dealership won't acknowledge the problem. They have been unable to reproduce it. I can reproduce it every morning when leaving the parking garage.

Is it available in manual? If so, I want it.


My Jetta Sportwagen (2010) is a manual TDI. I'd never go with a DSG for two reasons:

1. I like manual transmissions. 2. The added maintenance costs for the DSG for factory service is around $1k at the 40k mile point.


If you like manual, then the manual TDI will be very fun to drive. I can't be bothered with manual transmission, though. I have paddle shifters for the DSG but I never use them.


> I have paddle shifters for the DSG but I never use them.

Somehow I don't see that replicating my enjoyment of a true stick shift.


I think that the DSG transmission is always automatic, but it does have paddle shifters if you want to take over manual control.


"I now have to wash my hands after every fueling."

I would do the same with gasoline. In fact, I wash my hands after being in a car at all, just for good measure. There are quite a few poisons that accumulate in and around cars and roads.

That said, you can also do your fellow diesel drivers a favor and just wipe the handle on the pump with a paper towel, if there is one available.


I haven't driven a Jetta, though I did have a mid 2000's Passat petrol for a while. See my comment below, but I think the Golf TDi is the _perfect_ combination of power, fuel economy and driving fun. Try one for a few days and you'll never want to go back!


With hybrid plug-in cars becoming more standard, I think MPG is no longer an accurate or clear measure of efficiency. Are they saying that it gets 261 miles on the same amount of joules contained in 1 gallon of diesel? Or are they saying that with 1 gallon of diesel and a full charge it goes 261 miles? Needs more clarity.


They are saying it gets 261 miles for one gallon of gas plus some unstated electricity. They are counting the electricity as free. It's a completely bogus metric. I see a lot of Chevy Volt owners claim they get 400 MPG when they run on electricity 90% of the time.


Maybe they need a new measurement like GP100M (gallons used per 100 miles). So for the tesla, that number would be zero, but for the Volt it would be something like 1.7 (first 40 miles is zero, but last 60 would be at 35mpg).


The electricity needs to be factored in, it's not free.


Yeah, I drive a moped, and I get something like 95 MPG.

But a moped has a low top speed, and weights nothing compared to a car.

It's impossible for something that heavy to have better mileage than a moped.


Why aren't more car companies to using a diesel-electic powertrain? They've been used in the locomotive industry for decades!


Pressure from gas companies?


Mono-nitrogen oxides, aka NOx, are a regulated byproduct of diesel and gasoline engines. They're produced especially at high combustion temperatures and are a component of acid rain. NOx itself is pretty toxic to humans too.

Normal modern diesel engines are unthrottled [1] and control the power output of the engine by limiting the amount of fuel injected to the engine. The unthrottled bit is important--we'll come back to that. For now, just note that the engine computer can't regulate how much oxygen gets into the combustion chamber.

By comparison, modern gasoline engines use a throttle to control how much oxygen gets into the combustion chamber. On top of that, the fuel injection is computer-controlled to deliver enough gasoline to the engine so that all oxygen is consumed and there's some left-over gasoline from the combustion. That leftover gasoline plays an important role in temperature control--liquid matter tends to have much more specific heat than gaseous matter. The gasoline absorbs some of the heat released from the combustion such that combustion chamber temperatures don't spike, creating excessive NOx.

Back to diesel engines, because the basic design of diesels uses no throttle, the engine will have minimal post-combustion liquid droplets to absorb the excess energy (heat) that would cause massive NOx emissions.

There are workarounds:

I. Some diesel engines introduce throttles for this purpose [2], but adding a throttle to an engine introduces pumping losses to the engine. Being throttleless is one of many reasons why diesel engines tend to be more efficient than equivalently sized gasoline engines. This system tends to cost more because of the extra engineering involved.

II. Diesel exhaust fluid [3] can be sprayed into the exhaust stream of diesel engines. DEF is pretty much urea and purified water. The urea combines with NOx to form ammonia and CO2. A selective catalytic reducer (SCR) downstream converts the ammonia into water and N2. This system is somewhat simple and clean, but is open to lazy and cheap owners. I've been told that this system is disallowed in America for consumer vehicles. The DEF is consumed fairly quickly and needs to be refilled at least as frequently as oil changes. There's no reasonably cheap way to regulate that cars have adequate DEF, as the engines will run just fine without it. The only side effect to a diesel engine out of DEF is that it'll output NOx like your typical 1970's car in Los Angeles. Owners have little incentive (beyond moral obligation) to refill DEF according to a schedule. They might even be ignorant as to the side effects.

So long story short, producing consumer diesels that meet regulations is pretty hard. The freight industries are not as regulated regarding diesel (maybe land-shipping industries are more tightly regulated?...there are holes in my knowledge).

[1]: http://en.wikipedia.org/wiki/Diesel_engine [2]: http://en.wikipedia.org/wiki/Throttle#Internal_combustion_en... [3]: http://en.wikipedia.org/wiki/Diesel_exhaust_fluid


Given that hybrids have added complexity and cost, I wonder if the double premium of hybrid + diesel is worth it. The standard VW diesels already deliver amazing performance and economy. I would much rather see engineering talent focusing on improving the diesel even further than moving to a diesel-hybrid.


Any more information on this car? Is it in production? Just a prototype?


The concept is quite old. It was first presented to the public in '02 when Ferdinand Piech drove it to the stockholders meeting.

The model they are now considering to build is based on a variation of the concept, that they showed in 2011. If I remember right the first concept was not a hybrid but only powered by a diesel.

The car is said to go into production in a small series and to sell for about 50k€. I guess it has been pushed by Piech himself who is famous for pushing out complex engineering concepts to production even tough the company will loose money on every sold product. (See also Bugatti Veyron)


It's the third iteration of a prototype, though IIRC it was always billed as a prototype that could actually be produced or at least be very close: "Seriennahes Konzeptstudie".

http://en.wikipedia.org/wiki/Volkswagen_1-litre_car

http://de.wikipedia.org/wiki/Ein-Liter-Auto_von_VW

It says that they're planning a small production run of 100-1000, price expected in the € 30-50K range (not the $600 rumored), components are quite expensive, for example a carbon fibre body. My guess would be that they're limiting the production run because they're losing money even at those prices.

http://www.zeit.de/auto/2012-03/volkswagen-ein-liter-auto

On the other hand girlfriend's several year old Polo regularly gets 3L/100km, so around 78mpg. Every time we actually have to fuel up is a bit of a shock :-)


I figure a lease with no option to buy.


I found this clicking through their slideshow: "Another thing that has changed from past prototypes is that Volkswagen has confirmed that the XL1 will be produced and sold, though only in limited quantities. Sadly, there is no information on price yet, but the limited production probably means that it will be expensive."


Seems a bit disingenuous to call it 261 MPG when you have to plug it in.


I agree. They are treating the electricity like it's free (cost and environmental impact). I see a lot of Chevy Volt owners bragging about their "300 MPG" economy. If you have a dual fuel source vehicle (hybrid) and ignore one of the fuels, the numbers will always look good. Using their methodology a Nissan Leaf (pure electric) gets infinity MPG. What we need is a distance per fuels used, where fuels is all the gas and electricity.


Different sources of electricity have different environmental impact, but at least you can have a good idea of where your utility gets power from. At the same time, you don't know if your gas came from tar sands or easy to get (but dwindling) shallow Californian oil.

There is an electric equivalent mpg called mpg-e: http://www.edmunds.com/fuel-economy/decoding-electric-car-mp...


Correct. I think this is a 170 MPG diesel (or, converted, 152 MPG gas) one-seat microcar with a plug-in option, and that's all. 152 MPG is an impressive research effort for an in-house microcar. I don't know why they need to junk it up with dubious claims. It's bad enough that the Volt does this miscalculation as well, right on its dash -- another great car with misleading claims.


I believe they have been talking about this for a while. It's absurd that they are used today. They could be ran on SVO or bio-diesel. However the USA isn't a fan of a diesel engine unless it's in a pickup.


Am I the only one who thinks the design of the car is retro-futuristic?


Nice, but I can one-up it. I've got 2X Turbo Legs that don't require plugging in and run completely on food energy. Talk about eco-friendly!

Mind you, it runs a little slower, but I choose the planet and my children's future over convenience and luxury.


In some places, you cannot survive just by walking everywhere. My girlfriend's job is miles from the nearest house, and she is not going to spend 2 hours walking to her office each morning. Bicycle would be workable if it didn't involve cutting across a 55MPH highway.

A lot of US towns and cities are not really designed in a way that promotes non-automobile transportation.


Wow you're right, I should probably throw away my car and start walking to work, walking to the store, walking to class, walking to the lake pulling the canoe with my hands, trudging through a few feet of snow and ice in -10F weather to get everywhere.

Or maybe you're not actually better than everyone else. I can tell you that your fair trade coffee and quinoa sure didn't arrive from South America by foot.


Bike has even better specs!


You'd burn less petroleum if you drove rather than walking, and ate less food to compensate for your smaller calorie burn.




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