Germany has been at the forefront of diesel engine technological advances for years. The design and application of the diesel engine takes a different mindset and also a different customer base. GM virtually singlehandedly destroyed the desirability of passenger car diesels when they "dieselized" the 350 small-block. Cummins helped bring it back with the 'B' series developed with UPS and others for small and medium size trucks but that is much too large and heavy for a passenger car. Volkswagen, Mercedes and BMW have outstanding diesel engines which operate exactly the same as a gasoline burning engines to the point that your typical driver will not notice the difference until they go to a filling station. I am confident American manufacturers can adopt European engines for installation into American cars. I am much less confident American manufacturers will be able to design and manufacture a diesel engine from 'scratch' and would be extremely reluctant to buy one. Engine design seems to be somewhat intuitive and achieveing the 'optimum' design is an iterative process which needs a good starting point and years for improvement.
In Latin America, it's common to see diesel Toyota Camrys and Corollas, among other small Japanese passenger cars. Any idea why the diesel models of these cars aren't sold in the US? Is there a regulatory reason, or do they just not sell well in the US?
It may be that it's just a little to techie in the US. Here you need to use a DEF additive to reduce NOx emissions. This may be a put off.
VW TDIs are fairly common though. Currently the Cruze ECO gas engine is a better deal economically since it gets 42MPG on regular Gas. Diesel is more $ so 42 MPG would not be competitive. I don't find 55 MPG HWY too hard to get with the Cruze ECO but I do need to be careful.
BUT, the torque could be a game changer. I think the target is the VW TDI here. Not the broad market so much.
Diesel is very well suited to US market. The only weak point of diesels is lower power @ same engine volume due to lower max RPMs. But from driving experience it only matters when passing somebody @ 120 MPH - impossible on US roads. Always rent diesels when in Europe; all of them are 2.0L (Europe tax larger engines heavily), turbos for larger power. GM (Opel) are the worst of all (VW, BMW, FIAT, RENAULT): very narrow turbo RPM range (3000-4000) so turbo is practically useless.
Visiting Europe from the US on a regular basis and having lived there and owned a diesel-powered passenger car, I am very familiar with diesels and their benefits. I would like to drive a diesel, but with the current prices of diesel fuel vs. gasoline, diesels just don't make economic sense in this country. I do not expect diesels to take off in the US if the diesel fuel prices don't become more favorable with respect to gasoline.
I was always under the impression that diesel fuel was less expensive to make since it is less refined than gasoline, but the current prices don't reflect that. I suspect that people trying to "justify" the higher prices for diesel fuel are not completely unbiased and are really doing marketing. In addition, politicians in many states have decided to tax diesel fuel higher than gasoline, which further hurts diesels. This does not make sense during a time where fuel efficiency should be key.
@ltron: The Cruze Eco is a very nice car that I seriously considered buying. The fact that you can get 42+ MPG in a standard-powertrain vehicle that costs around $17,000 really undermines the case for hybrids, in my opinion.
I wound up going with a base-model Nissan Versa sedan that gets about 40 MPG (combined city and highway) and cost me a little under $13,000. It's the best value, by far.
All this from THE Company that single handedly soured the American public opinion for Diesel powered Autos with the ill conceived Olds Deisel onversion of the late 70's.
There has not been any legislation against Diesel autos in this country, just a long held prejudice against them stemming from that ill fated excusion that lingers to this day.
Two things are the death of diesel engines, both related to poor filtration, and that engine sufered from both and was doomed from the start. Inadequate oil filtration and inadequate fuel/water separation.
Both of these things are amply covered in all true heavy equipment, truck and marine applications and have helped to make diesel use in those fields the mainstay of those industries.
Is GM to be trusted a second time, only time will tell. One can only hope they learned from thier earlier fiasco.
You took the words right out of my mouth. The 350D is the design single handedly responsible for America saying yuck to diesel powered cars for the last 30 years. The diesel has gained much ground back in the truck market, but with the EPA choke hold on anything holy, the diesel is a more complicated mess of ill fitted emissions controls than any underpowered dog of the 1970's...
If I could have a diesel without the garbage, I'd take it. People have a hard enough time maintaining cars with gasoline engines in them, imagine the mainstream disaster this will bring. Truck owners tend to be more mechanically inclined, and apt to pick up on things if they are going wrong. Can you picture a 19 year old tiny bopper going to college, who can barely drive, let alone figure out where the oil goes and forget what grade you're supposed to use with one of these?
Second disaster in the making. Hope I'm wrong, but generally speaking, GM hasn't had the best of luck in breaking new ground... Chevy volt bring back any memories?
"Can you picture a 19 year old tiny bopper going to college, who can barely drive, let alone figure out where the oil goes and forget what grade you're supposed to use with one of these?"
My 17yo daughter (wouldn't call her a teeny-bopper) has no trouble figuring out where to put the diesel or oil in her car, or how to address other challenges if fuelling up at a truck stop. It really isn't that difficult. She loves her 10 year old VW 1.9L TDI, but it's old enough that it doesn't have all the extra emissions stuff. This means it still has respectable power, and comparable fuel mileage as the Cruze even with the auto trans.
I congratulate you on raising a fine daughter and contributing member of society. Being an engineer's daughter I'd expect nothing less of her! You do have to admit however, you know which group of late teen, early twenties folks I'm talking about.
Thanks, but I guess the point that I forgot to make is that it really isn't any different than owning a gasoline powered vehicle. I have several gassers, and each seems to specify a different grade of oil, so the diesel is just one more bottle in the shop. Many more stations around here are carrying diesel, and the truck stops are even putting in seperate islands with lower flow nozzles for passenger vehicles. Some of the new diesel vehicles have a tank valve that makes it much more difficult to insert the smaller gasoline nozzles, reducing the possibility of putting in the wrong fuel.
Whereas electrics and hybrids seem to shine best for short trips, diesels excel on longer commutes, and I think the infrastructre is finally moving in the direction of US diesel acceptance.
I had a great experience a couple years ago driving a Volvo station wagon on the A3 autobahn in Germany. It had a 4 cylinder turbo diesel engine that would keep the vehicle at speed, but needed some time to get there when I had to get out of the passing lane and slow down in the middle travel lane. Much of the time was spent between 170kph and 200kph (106mph and 121mph), while I did manage to get it up to 230kph(143mph) briefly on a long, straight downhill. That's much faster than I can legally drive my C5 Corvette in this country.
Someone please tell me the difference in the two grades of Diesel there: besides price, of course.
I do not have enough expertise on engine block design to comment on the conversion of a gasoline engine to Diesel. Pressures on a Diesell block and head have to be much greater than for a gasoline engine. The number and size of headbolts has got to be engineered, and I believe most gasoline blocks are stuck with the number of headbolts originally chosen.
My daughter was interested enough to ask about what is under the hood when I gave her a car for college. I'd do routine maintenance when she'd come home for vacations and breaks, and she would watch and ask how the engine works and what the various components were. Apparantly, she learend enough to talk knowledgably about engines with boy students because she said they would ask her what's wrong with their cars whenever they were having a problem. Of course, she didn't know enough to fix problems, but she apparantly knew more than they.
California and Mass essentially banned diesel cycle, so car companies don't want to put a product on the road that can't enter the largest market in the country. The EU has lower standards for NOX. The car companies have now developed CATs that can lower the NOX and have particulate traps to reduce those emmisions so they can be sold in CA.
Every Mechanical Engineer should know that engine torque is what moves motor vehicles. Horsepower is the product of torque and RPM, and is important for those looking for high performance. High horsepower means you can keep your performance vehicle in a lower gear longer when accelerating in order to take advantage of more torque multiplication. From years of studying advertised engine performance specifications, it can be seen that higher compression ratios result in higher peak torque values, usually in engines for performance vehicles. Therefore, Diesel should make much higher torque because of much higher compression ratio.
Keep in mind that there is "mechanical" compression ratio, which is a comparison of cylinder volumes and "thermodynamic" compression ratio which is a comparison of actual cylinder pressure at TDC and atmospheric pressure. The ability of Diesel and Otto engines to breathe in more air at higher RPMs, "volumetric efficiency", is what allows the torque and horsepower curves to fall off at higher RPMs.
Two important things I remember from Thermodynamics 101 are: 1. The way to increase power output from any internal combustion engine is to flow more air and heat it up higher; 2. The higher the engine's thermodynamic compression ratio, the higher its efficiency, exponentially.
Does Low Sulfur Diesel fuel also provide a torque boost from a 12% higher heat value, 129.5 BTU/gal. versus 116 BTU per gal.? I guess you actually do get what you're paying for as Diesel fuel where I live costs 12% more than regular gasoline. Its heating value in BTU/lb is slightly less than gasoline, and in combustion, it's the respective masses of air and fuel that are used for calculations of fuel mixtures. But, we do buy both fuels by the gallon, and using vehicle miles per gallon - MPG- we can easily calculate fuel cost per mile.
If one is trying to calculate total engine operating expense between the two engines, maintenance needs to be considered? For me, the greatest concern would be how much does it cost to have Diesel fuel pump replaced. Also, how much does a newer direct injection gasoline fuel pump cost versus a convention 60 PSI fuel pump?
California continues to penalize Diesel owners. I drive an '84 Mercedes and a Ford PowerStroke. Diesel fuel is consistently more expensive than premium gasoline, mostly because CA insists on taxing at a much higher rate than gasoline. In 2004, Sales tax prepayments were 0.09/gal for gasoline and 0.07/gal for Diesel. Today, it's less for gas at 0.07/gal but has soared to 0.29/gal for Diesel. CA has also now mandated smog checks for diesels even though there is no measuring equipment. The "check" takes about 5 minutes and consists of a visual verification that you have not modified the intake or exhaust system and costs $80.
Several years ago, I had the pleasure of renting and driving a diesel powered Ford Focus station wagon while in France on business for 3 weeks. I would have purchased that vehicle in a heartbeat in the US if it was available. Once it got off idle, you'd never know it was a diesel. Plenty of power and real stingy on fuel.
I retired my '84 300D after 375K miles when the lift went through the rocker panels. Maine winters and road salt ate my car! The American market has not been receptive to diesel engines. The stigma of driving a smelly, sooty, slow accelerating, noisy vehicle which made your hands and clothes smell when you filled the tank was too much to overcome. Add to this the premium cost of initial purchase and inability to get anyone other than the dealer to service the engine and it becomes difficult to convince buyers. Volvo and Peugot in the 70's and 80's had a low compression (18:1) diesel which smelled terrible, accelerated poorly, and due to lack of sympathetic service mechanics usually were fairly unrelible. VW and Mercedes never gave-up but their sales were quite slow and diesels owners became almost a cult. Because of the legislation to limit soot, both companies had to come up with particulate filters which needed frequent changing, plus as the compression ratio was upped to increase fuel efficiency, temperature and thus NOx emissions went through the roof which required heroic efforts to meet emission laws. Today's best diesel engines meet (for now at least) the soot and NOx limits set by CA, but there is every indication that new laws will be enacted to further limit soot, odor and efficiency.
I agree for the most part with bob from maine. Other threads blame GM etc for bad engines. But the main reasons for the dislike of diesel are soot and smell. Personally the Manufacturer that did the most to put a bad rap on diesel is Mercedes. Their older cars with the soot pouring out at every acceleration were horrendous! The entire rear of the Mercedes would be black from soot. They smelled horrible to even be around, etc. For some reason there were quite a few on the road. Poor man's Mercedes? Now we have the Dodge Ram trucks that people are hopping up that pour the soot out. I have not been in the emissions business in several years but I understand that at least here in California there are steps to regulate the amount of soot. Finally! IMO American manufactures should not be allowed to sell their version of diesel engine, I understand in Europe the technology is much better.
But I don't think Germany tries to reach the same low emission levels required here in the US. We'd be far better off with more, clean, diesels on the road. We could probably shave 1-3% of our total liquid fuels consumption.
There are some very good points made here. The Chevy 350 diesel was a fiasco from the start when GM tried to "convert" a gasolene engine to diesel. Bearings, rods, head bolts...you name it, they just didn't have the design expertise. The fact that the Cruze diesel is a European design and in use there is a tremendous advantage. The engine looks robust.
I owned 3 VW diesels from the 70's and 80's that lasted forever ('78 Rabbet had 0ver 350,000 when traded for an '86 Jetta) and all returned 50+ MPG. The reason I got away from them was mainly because my commute changed from 106 miles to less than 6 miles a day and gas is about $.40/gallon cheaper.
I think the reason for the price differential has more to do with Federal fuel taxes to be sure the heavy trucks pay their fair share of road use taxes. Please correct me if I'm wrong, but I always understood the refining process to be easier and cheaper to make diesel than unleaded gas. After all, many in the Northern part of this country heat their homes with fuel oil which can be filtered and run in a diesel engine (illegal, by the way).
Another point against automotive diesel is the gelling of diesel at temperatures below 25 F. Living in Pennsylvania, I wiould carry a 5 gallon can of kerosene in my trunk all winter. When filling the tank, I would add 1 gallon of kerosene first and then fill the tank (about 12 gallons) with diesel. This was the cheapest form of anti-gel possible and never bothered the engine or my fuel economy. The ONLY engine maintenance these three ever needed were oil & filter changes every 3 months (about every 6,500 miles).
Actually, General Motors had a great amount of diesel engine experience prior to designing the ill-fated diesel cars. GM was the maker of GM diesel engines for trucks, boats, train locomotives, and small ships, as well as supplying numerous industrial customers.
The problem was more likely one of excessive cost control efforts and insufficient development time. The engines themselves were relatively simple and straight-forward in design. it is also possible that experienced GM diesel engine experts were not put in charge of the car diesel effort.
There was nothing inherently wrong in basing the engine on a re-design of an existing block. A review of the key dimensions--crankshaft main journal diameter, crankpin overlap, rod journal diameter, cylinder bore center distances relative to bore diameters, etc.; all suggest a quite robust design--especially in consideration of the meager power and torque output. A friend bought one of the first Cadillacs with the diesel engine and, new, it ran with remarkable smoothness and quieteness. The quietness came from moderate RPM levels, an indirect fuel injection system, and Cadillac sound proofing efforts.
Yes, GM did have a lot of expertise with diesel engines:
Detroit Diesel made engines for use in GMC truck and busses, and for sale to other truck manufacturers.
Electromotive Division made its own engines for its locomotives.
GMC Truck & Coach made its own engines for trucks, as well as for driving irrigation pumps. (I don't remember exactly when they stopped, but they built the GMC motor homes in the same building--Building 29--that they used to build engines in, and that started in 1973.)
Sometimes different GM divisions worked very well together. But I think that was more the exception than the rule. There were not well-established communication paths between the divisions, and sometimes there was a bit of not-invented-here syndrome, so it would not surprise me if the problem were that the people designing the Chevy diesel engine did not have access to all the design wisdom that existed in the other divisions.
I don't know any of the specifics of that particular engine, but this would make sense based on my experience working at GM for several years. (BTW, the problem isn't just GM. My experience is that in huge corporations, sharing of information is awful, because people don't know who has the information and how to get access to it.)
Yeah, I'm with you on this one. VW and Mercedes have been putting diesel passenger cars on the roads continuously for decades and that institutional knowledge of how to make them work is not trivial, even if GM incorporates a European design engine, because there is still much that has to be done to fully integrate it in your design.
My wife and I test drove a VW Jetta TDI back in '05 when we needed a new car. Loved the way it drove, but the price differential of $6,000 plus between the base gas model Jetta that they were discounting and the TDI in which dealers were putting a premium on the MSRP made that an easy decision. Not to mention that my commute is 5 miles each way. Even in '05, when diesel in Maryland was actually cheaper than regular, it was going to take 150,000 miles just to "break even".
I wish GM well on this endeavor, but I personally wouldn't buy a diesel passenger car from GM until this car gets at least five or six years on the market. I'll let others deal with the growing pains.
The GM Duramax diesels seem to be pretty good. Their new 2.8 L V6 Duramax sounds promising. The original Olds 350 diesel was a disaster because GM rushed the engine market. It was a shame that it happened and that another manufacturer didn't jump in and fill the vacuum before the market totally soured. State and federal fuel taxes may prove to be a problem, but VW has been able to sell diesels. Hopefully, GM will have better luck this time around.
Diesel more expensive than gasoline to produce? Never heard that song sung before. I'd always assumed that the reason ships (even giant container ships), locomotives, commercial vehicles, buses, military armoured vehicles, standby generators, stationary power generators etc all use diesel engines is because the fuel is cheaper and the engine more efficient.
In my country, diesel is more heavily taxed than gasoline, the reasoning being that the goverment will claim the same tax figure even if your engine is more fuel efficient. Commercial users get a tax rebate.
If you want fuel efficency, diesel is the way to go.
Charles, I think SOMEBODY (named Charles) needs to do a little bit of research on the tax issue. Like what exactly are the US Federal and average state taxes on diesel fuel vs. gasoline. I have heard (no hard facts though) that the total tax burden for diesel is WAY more expensive than gasoline; my experience in driving several different diesel vehicles in EU recently strengthens that belief, as diesel there is significantly cheaper per liter than gas! I know that EU has much higher tax rates on gasoline than US average, and suspect it is much lower (than US) for diesel! Other posters have noted (correctly) that diesels just aren''t economically feasible in the present US arena. There is also somewhat of an infrastructure issue with diesel fuel availability much lower in US than in EU (where virtually ALL fuel stations have both). Personally, I would favor CNG-fueled diesels, but that is an even bigger infrastructure challenge. However, the CNG issue does have something in common with EV: there are already "home recharging units" for CNG that could work great for even long-range commutes. The interstate travel trips would still need new infrastructure, however.
I was surprised; only $.06 more per gallon for diesel. Very interesting: some states stand out in their region (like NJ in the NorthEast with sub-median taxes all around; just don't ask about real estate ones!).
Ratsky, the point we were trying to make is that diesel fuel in Europe is taxed differently than gasoline in Europe. A representative from GM and another from the Center for Automotive Research used the term "diesel subsidy" -- meaning that diesel fuel isn't taxed quite as heavily over there as gasoline is. If there's information to refute that, I'm certainly open to hearing it.
Seeing the comments below, I just wanted to point out that the UK also taxes diesel more than regular, but the mpg more than makes up for it.
I drive a Peugeot turbo-disel and get 59mpg, whereas my wife has a Toyota Auris hybrid and only gets 42mpg. I also get much better highway performance due to the significantly higher torque, so my one surprise is that the GM US mpg is so low.
Anyway, my main point was that I have personal exoerience between hybrid and diesel performance, which still makes the increased tax worthwhile.
To Charles point about Eupoean diesel engines, they certainly have taken a big jump in both performance and MPG in the last 5 years. My wife previously had a older technology Citroen diesel C4 and that gave no better performance than her current hybrid.
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