I see a fair amount of large diesel trucks but why not cars? Its cheaper than regular gas (easier to refine), gives you torque and better gas mileage (higher energy density), and they seem to be pretty reliable (fewer parts i.e. no spark plugs). The only place I have ever found diesel is at truck stops and places near highways. If you could get diesel more readily in the city I think more people would use it. I remember my friends old diesel mercedes had to be primed for like 15 seconds before you cranked it over but I am sure they have improved by now. What are some of the stigma's/problems associated with diesel engines and why haven't they caught on here?

 

Diesel is just another layer of things to go wrong-
Check out any statistical measure of cars, (Edmunds, Consumers, whatever.) and you will find the diesel version of a US car was (I have to say WAS, since there are no more diesel US cars....) less reliable than the gas version, and the fault was always the 'diesel bits' - the pumps filter, injectors, and especially the heads/gaskets.

US automakers screwed the diesel-
When the automakers got the diesel bug in the seventies, they meant well, but went cheap. The cars were just gas blocks with some 'diesel bits' tacked on.....and (wouldn't you know it?) the diesel bits had a habit of falling off.

Fuel is way cheap compared to elsewhere-
The US has really cheap fuel, even at todays prices it is cheaper than in the sixties! Way more attractive in high fuel cost places.

People just don't like to wait for a diesel-
Your average US consumer doesn't want to push a glow plug button for even ten seconds! It is literally too much hassle...
And if it won't put out 100% power right away...look out.

Smelly, Noisy, Rough, Heavy, and a maintenance hassle. Doomed from the get-go. The only people who will buy one are 'Wanna-Be' truckers, who think it is a 'big rig', or pollution-phobic green whiners who will put up with all the problems in the 'self-flagelation' kind of attitude - "It's a lot of work, but at least I'm saving the planet...."

Don't get me started!
.
.
.
doc

Tofu, soy beans, save the whales....

 

Thanks for the response.

 

Diesel fuel actually has significantly lower energy density than gasoline - it's garbage fuel (literally, if you burn bio-diesel made from old frying oil!). The reason diesel engines have more torque and get better gas mileage is because of two factors - a 20-something:1 compression ratio (compared to 9:1 or 10:1 for current gasoline engines), and no throttling losses. Those mean that the engine is much more thermodynamically efficient at using the energy that the fuel does contain, not that the fuel contains more energy.

Problems with diesel? Several - primarily emissions related. A few years ago, California practically outlawed diesel passenger cars by tightening up emission regulations to the point no manufacturer could meet them with current US diesel fuel. Therein is the other problem - the real improvement in diesel engines in Europe came with the advent of common-rail injection engines over the past 5 years or so, where the fuel is injected at much, much higher fuel pressures than in earlier diesel or gas engines. For example, the fuel pressure in an RX-8 will be somewhere around 80psi. On a common-rail injection engine, the fuel pressure will be somewhere around 20,000 psi! However, CRI diesel engines require very clean fuel, specifically low sulfur content, and in North America the diesel fuel is too dirty to use in a CRI diesel engine. New government regulations require that all diesel sold here by 2006 have similar low sulfur content as Euro diesel fuel, at which point the CRI diesel engines will be viable in this market (and able to meet California diesel emission regulations).

Regards,
Gordon

 

"Diesel fuel has a higher energy density than gasoline. On average, 1 gallon (3.8 L) of diesel fuel contains approximately 155x106 joules (147,000 BTU), while 1 gallon of gasoline contains 132x106 joules (125,000 BTU). This, combined with the improved efficiency of diesel engines, explains why diesel engines get better mileage than equivalent gasoline engines. "

Thats just info I got from http://auto.howstuffworks.com/diesel3.htm

But yeah I know about those hippies that drive around the country on oil from fast food grease traps and Im sure it is a bit smelly. I had heard things both ways concerning it being a "clean burning" fuel despite putting out much more visible exhaust.

 

well said gord and doc.

 

My apologies! That's what I get for relying on my memory from my "Theory and Practice of Internal Combustion Engines" 3rd year engineering course 24 years ago!!

Regards,
Gordon

 

You can thank GM with its crappy gas conversion diesel for souring US opinion on the technology.

And Gord, common rail diesels have been avaialble since last year in this country. Cummins, for one, in the Dodge pickups.

 

With the new generation glow plugs in latest diesel engines, there is no waiting anymore. You just turn the key and start in the same move. Only by very cold mornings in the winter, will you have to wait 1, maybe 2 seconds, no more.
Diesel engine noise has neen improved by better encapsulation of the powertrain and by use of common-rail. This technology allows for several injection pulses during the same combustion process. In other words, the same amount of fuel is burnt over a longer time, which means that the pressure gradient in the cylinder is reduced and so is the noise (that's proportionnal to P gradient). Higher injection pressures ensure proper vaporisation for improved combustion and reduced emissions.
Diesel cars represents a huge part of car sales here in Euope, and for up to 65% in Belgium, for example.
My wife has an Audi A4 1.9L TDi with the VW designed "Pump Düse" system that allows higher pressure than common rail but prevent any 'pilot' injection (early injection in the cycle).
It's torquey like a US V8 engine, has 130hp and very good performance feel and driveability.

Nevertheless, they are all f****ing noisy and they smell!

I will never buy a diesel car, except maybe a BMW 3.0L, the best one on the market here.
The best 4 cyl, is the new Honda engine. Mind you, it was designed by the engineer who designed the VTEC and VTi systems on petrol engines. He hates diesel so he designed a very refined engine that happens to burn diesel.

IKN

 

I for one am glad the US hasn't had the diesel plague until cleaner diesel technologies are available here. All the soot and noise would make for even nastier cities. Houston with more diesels... now there's a great idea. In fact I saw something the other day saying how diesel soot has increased the albedo of snow in many frozen parts of europe and as such, our ability to reflect UV back into space has been lost; hence global warming.

I'm no tree hugger, but I'd rather not have a fine black layer of soot covering everything in sight... It's already bad enough following a school bus, or better yet someone's pickup that has the injector pump turned up. But the newer diesel tech (not just ULSD) that is better at capturing and eliminating some of the exhaust (better emmissions systems and direct injection) might be a reasonable way to return the diesel to the US in force.

As for being easier to refine diesel than gas... they both have roughly the same required refining processes, but yeah, diesel is a heavier HC. I work for a company that is revamping a refinery to produce ULSD and this work was predicated by previous jobs doing low sulfer gasoline - and they basically involve much of the same scope...

 

mercedes just released a E class diesel on monday the 12th

 

It's about the same price at the pump as regular,
Older diesels had no torque, that's why so many have turbos, like said above with compression and gearing is how they are able to pull now.

 

While we're talking about diesels... How 'bout injecting some propane in there too?

<required hillbilly accent>

I done learnt 'bout this a year or two ago I reckon, and sho nuff if it don't make yur truck hawl a$$... So the next time yur baby's mama sends ya down to the piggly wiggly and the beverage barn in yur F-250, jus think that you could be back in the trailer while that hottie from arkansaw is still on Springer....

</required hillbilly accent>