I want to buy a new car that is coming out this model year with a Diesel engine for the first time. I specifically want the Diesel, for better MPG and driving range (which, of course, are directly linked).
Everything else being equal, I am expecting the Diesel engine to cost (very) roughly $1,000-$2,000 more. Why is that? I am pretty sure that Diesels have a higher compression ratio, so the engine has to be ‘tighter’. Is that the reason? Or is it a “supply and demand thing”? Or, what?
If it matters, I am interested in the 2014 Jeep Grand Cherokee with the Italian 3.0L V-6 Diesel.
(And can we keep the Fiat jokes to a minimum, please? Thank you.)
Besides what you say in your OP, I’d guess that they cost more because they have a more limited production run (i.e. they make less of them, which drives up the cost or makes them a more premium product). In addition (grain of salt) they have to be made stronger than regular gas engines, thus have more engineering and, I assume, materials involve, thus also driving up the cost. ETA, plus (ironically considering my first answer), there is more demand, since production is more limited, thus allowing companies to charge more.
The first widget you make costs you a million dollars, the millionth widget you make costs you a dollar (not really but if you depreciate the cost of tooling and set-up over time you’ll see that the more you can make and sell, the further you can drive down the price of an individual unit).
I knew it was the Grand Cherokee before you said it! I have a 2012 and love mine.
Diesel engines must be stronger because the pressures involved are higher. Stronger means more material, more work manufacturing them, etc. Also, the US is still collectively rather tentative about diesel vehicles, so they don’t expect to sell as many as the gasoline version and need to distribute their fixed costs over a smaller number of vehicles.
Finally, to some extent, they can justify charging more by saying you save the money on gas.
Yet these are global companies in a global marketplace and diesels predominate in much of Europe. (More than half of all cars sold in Europe are diesels.) They are 12% of all vehicles sold in the world. This is not a niche market.
Additionally - diesel engines generally burn “dirtier” than gasoline engines, as a consequence of the combustion process (higher temperatures, higher pressure, leaner mixture, etc.) In order to meet emissions requirements, they must utilize more complex (ergo more expensive) emissions systems.
I know the BMW and Mercedes diesels sold in the US have a “urea catalyzed” system that uses urea to remove nitrogen oxides from the exhaust. There is a separate tank of urea you have to refill every 15,000 miles or so.
The new high performance diesels get their performance from the “common rail” fuel injection system. Since a diesel doesn’t use a spark plug, but relies upon compression ignition it has been very hard to control the exact ignition timing, thus giving up one of the key advances in engine technology afforded to conventional engines. A common rail injector allows for precisely timed injection of fuel (and actually more than one injection per stroke) to gain a very precise burn. Fuel can be injected into an already compressed cylinder, and will burn immediately, thus exactly controlling the time of ignition. However the precision needed in the injection system, and the insane pressures at which they work (30,000 psi), result in engineering that is quite significantly more expensive than a normal fuel injection system.
He’s asking about the fact that model for model the diesel version costs more.
That’s not because of low volume, as this article from the UK confirms. It’s from possibly from the basic higher cost of the engine and definitely from the pollution controls.
That’s a roughly $1300 diesel version purchase premium in the UK where over half of the cars on the road are diesels.
Since it’s been answered, a couple of questions. Does the increased mpg even out with the increased cost for the diesel fuel here in the US? What’s your $/mile - not mile/gal.
Increased range? You should stop for a snack, bathroom break, walk around every 2-1/2 to 3 hours. Combine a break with a fuel up. You don’t drive and eat at the same time (text/drive, phone/drive) do you? That’s a proven killer on the highway. Not meant to be a snark - I’d like to keep you alive and posting on the SDMB.
Just a couple more data points – I ran the configurators on vw.com and vw.co.uk for a Beetle with both the 2.0 TSI engine (200hp) and the 2.0 TDI engine (140hp). UK numbers are in pounds.
So you can see that the diesel only carries a $100 premium in the US, but an 1150 pound premium in the UK. Strange.
Note that I had to use the Beetle because I couldn’t find another car in the US that was offered with the 2 liter turbo engine in both gas and diesel. Our Jetta, for example, uses a 2.5L naturally aspirated motor, which is much less expensive than the diesel variant. I should point out that use of the 2.5L for North American markets represents a recent shift in attitude for VW; an effort to reduce costs in order to be competitive with domestically produced cars.
I guess what I mean by that is that while diesels have historically required more expensive engineering and components, that gap depends entirely on what management is willing to pay for a gas engine. For instance, Mazda’s new Skyactiv-G line of engines runs at 14:1 compression with direct injection. With that sort of technology, there’s not going to be much, if any, cost savings over a diesel. Likewise, VW’s 2.0 TSI engine is rather sophisticated, so it’s no surprise that it costs about the same as their 2.0 TDI. The only question left to be answered, then, is why the Brits have to pay so much to get one but we don’t.
eta: What I’m getting at is that you can’t just look at the fuel type, you have to look at the engine as a whole. Two engines that both have turbos and run at 14:1 compression are going to cost about the same, regardless of the fuel that gets squirted in, but one engine that runs at 15:1 compression (diesel) is going to be more expensive than a low-tech gas engine running at 9.5:1 compression, which will likely make up the power difference with displacement.
If you do the “compare side by side” on the EPA’s fuel economy site ( http://www.fueleconomy.gov ) one of the items is “cost to drive 25 miles.” I just plugged in a 2.0L gas Jetta versus the TDI Jetta and it’s $2.95 for the gas one and 2.88 for the diesel. So right now there's a very minor difference. Although this is the biggest price difference for diesel I can remember and I doubt it will last, in which case the economics tilt much more heavily towards the TDI. Even with current prices, saving .07 a mile means the TDI option will pay for within a few tens of thousands of miles.
Thanks for your concern, smithsb. Good tips, yes. I’d rather stop to stretch my legs at a scenic overlook taking pictures, than standing at a gas pump sniffing the fumes and then walking to the shop for another Diet Coke.
Not to mention the cost of your time spent going to the gas station and filling your tank. I’ve never done the math for that! I suspect that info would be significant (I’m guessing maybe 1.5X to 2X the number of fillups with gas vs. diesel. How much time is spent on average filling your tank - maybe 5mins? Just a SWAG there.)
Also, I’ve read that the EPA test cycle from which they determine their official MPG values tends to overestimate the MPG for a gas engine and underestimate the MPG for diesel. I have no cite for this now, however.
