The rise and rise of diesel

I see your grammar ("Back when I was driving truck") is just as good as your understanding of basic engineering principles.

Next time I encounter a car made in the last 20 years that is powered by one of the HD engines you remember from way back when, I'll let you know.

If it's burned *well,* it doesn't smell much at all. It's the impurities and/or imcomplete combustion that make exhaust smell.

nate

Possibly... :-)

As Mr Stern seems to be able to recognise (or not) all these smells I was keen to try out his measuring gadget, whatever it is....

DAS

True- a well-tuned 60s car burning leaded racing fuel smells like heaven on earth, but a late-model Toyota under hard acceleration smells like a truckload of rotten eggs :-p

Maybe, but I really doubt it. For one thing, the raw FUEL will still smell horrible when you're re-filling the car. And the exhaust will still smell worse than a similarly-catalyzed and cleansed gasoline engine. Its just the nature of the fuel itself.

Well, yeah! An old Detroit exhaust note is an octave higher than the others at the same RPM, and 2-stroke diesel exhaust has a characteristic smell (the same applies to EMD locomotives versus GE). But I can't really tell a new 4-stroke Detroit Series 60 from a Cummins M-11 just by sound or smell.

Most of the volume of pollutants in either a diesel or gasoline exhaust stream are odorless- CO, CO2, NOx. Its the trace elements and the unburned residuals that leave a smell. Low sulfur fuel will eliminate many of the stinky trace elements (hydrogen sulfide, sulfer dioxide), but the unburned residuals of diesel will always smell a bit different than the unburned residuals of gasoline. If anyone can get a catalyst to clean them thoroughly enough, the smell MAY get down to a tolerable level, but I'll bet you any sum within reason that you'll still be able to tell a diesel from a gasoline engine with one whiff.

What part of WRONG don't you understand?

Matt

Is this the best criticism that you can think of? OK, explain the engineering principles that say that radically changing the chemical composition of diesel exhaust using modern pollution control equipment will have no affect on the smell of the exhaust. And then explain, using basic engineering principles, why similal pollution control equipment on a gasoline engine makes a dramatic difference in the smell of the exhaust.

The principle applies. A catalyzed, soot trap equipped diesel will neither smoke nor smell like a standard diesel.

Matt

Personally, I much prefer the smell of diesel fuel. I find gasoline the more obnoxious smell.

I never said that a diesel would be as odor-free as a gasoline engine. I said that a diesel burning low-sulphur fuel and equipped with pollution control devices would produce less odor than an engine not so equipped.

I drove a diesel car when in France several years ago (I believe it was a Peugeot) and it produced no visible smoke and no objectionable odor. I didn't use enough fuel to have to refuel it, but there was certainly no diesel fuel or noticeable exhaust odor when driving it. I didn't stick my nose up the tail pipe to get a close whiff, however. :-)

Matt

Tell that to Dan. He still thinks all diesels smell that same and always will smell the same.

Again, I don't believe I ever said that you wouldn't be able to still smell a diesel or that a diesel would smell the same as a gasoline engine. I simply said, and I think you are saying the same, that a diesel burning "clean" fuel and with pollution controls will smell much less intense than a typical diesel does today.

Since the main difference between the fuel used by catalytic converter equipped cars and non-cat cars was the elimination of lead (which I also think is basically odorless), to what do you attribute the the dramatic reduction in smell emanating from a modern car as compared to its 60s brethren?

Matt

Of course not. You've seen otherwise. But I did think it bore mentioning.

Whether you eat at McDonalds or SaladSalad! has no *effect* on your s*it smelling like s*it.

OK, you go out and stick your nose up the tailpipes of VWs and Oldsmobiles. I don't have to; I've been around enough of them in traffic to stand behind my statement. But then, you're the kook who likes the smell of diesel, so I'm not sure your opinion counts.

my brother drives an '85 Mercedes diesel wagon -- 300D. He runs a lot of biodiesel in it, made from used vegetable oil. Burns 75% cleaner than regular petroleum diesel. Even dirty petroleum diesel doesn't put out any more pollutants than a regualr unleaded gasoline car. Plus you get 50mpg in a diesel. a diesel will run on canola oil, peanut oil, veggie oil, etc.. There are agricultural co-ops in the midwest where you can buy biodiesel made from canola oil that's grown in the midwest right here in the USA. Let's get off the Middle East oil teat and run clean burning biodiesel. let the ragheads keep their dirty petroloeum.

"From the Fryer to the Fuel Tank" is a neat book.

Well, what you eat does have an affect ... but I'm not going there ...

Matt

Fuel, not exhaust. Are you still having trouble keeping them separate in your mind?

Matt

Ditto the HempCar (

That's not true. NOx, SOx and PM10 are higher (sometimes *WAY* higher) in a diesel car running on diesel oil than in a gasoline-powered car of comparable model year. Given that the current state of the art in gasoline engines is "Damn near zero toxic emissions", you'll have trouble pushing the idea that diesel engines are cleaner.

I don't have enough info to know the emissions characteristics of a diesel engine operating on plant-based fuel, a specifically-biofuel-engineered engine running on plant-based fuel, etc. relative to a diesel engine on diesel oil or a gasoline engine on gasoline.

I agree that's a good goal to work towards, but I am not convinced biodiesel is the magic bullet, given the energy input vs. biodiesel output equation. Check this thread:

-Stern

Ah. You have another name for "fuel that has been burned"? Other than "exhaust", I mean?

...only that is not the case at all. Between the unburned fuel, the burning crankcase oil, and maybe some other factors, the Oldsmobile diesels stunk horribly. On the other hand, the current VW TDI's don't smell at all except for a short time during warmup. The turbocharging helps by providing extra air to more completely burn the fuel, as does the more up to date combustion chamber design.

"Daniel J. Stern" wrote in news: snipped-for-privacy@alumni.engin.umich.edu:

He bought the '85 MBZ wagon for $800 from one of those charity places that accept donated cars. The previous owner was a maintenance freak and obsessive, so he recorded every oil change and service (all done at a mercedes dealer) in the owner's manual "notes" section and put the receipts in a ziplock bag in the glove compartment. The car looks and runs like brand new (120K miles) and is a CA car, so no rust issues. It's a cool car. It looks like the one in that Alan Alda film "Four Seasons", the one that crashes through the ice. That was a '75 to '85 body style. the guy in the film calls his mercedes a "thoroughbred".

I do that to my cars also: record services/repairs in the notes section of the manual and keep the receipt. Helps for resale value. Those charity car places are a good way to pick up cool cars for next to nothing. I bought an unmolested '64 Dart sedan with only 80K miles for $400 at one. The Dart was VERY solid, with an almost like new interior. its /6 ran perfect, didn't burn or leak any oil, just had a faded red paintjob is all. I should have had it repainted instead of selling it! But I was in my "if I am going to fix up an old A-body, I want a Valiant wagon, not a Dart" mode. I made sure it went to an appreciative person though.

In a "Smart Car" thread I put out the following info I obtained from a UK govt website:

You might find the data interesting in the petrol/diesel debate.

Merc diesels produce less CO but more NOx than their petrol counterparts. (They are also quieter on the move.)

Automatic transmission.

S 320 CDi diesel (to latest EU standard IV) (followed by S 350 petrol in brackets Euro standard III)

CO2 - 209 g/km (266) Noise level (moving) - 69 dB(A) (74) CO - 0.069 g/km (0.185) HC - n/a (0.050) NOx - 0.228 g/km (0.046) HC + NOx - 0.240 g/km (0.096) Particulates - 0.003 (n/a)

C 220 CDi diesel (followed by C 200 petrol)

CO2 - 166 g/km (204) Noise level (moving) - 73 dB(A) (74) CO - 0.030 (0.591) HC - n/a (0.079) NOx - 0.339 g/km (0.019) HC + NOx - 0.350 g/km (0.098) Particulates - 0.035 (n/a)

DAS