The interestingly pedantic DIESEL thread

[vorsprung]

Originally Posted by Hammerdown

Surprised about the tractors, Bob. I would have thought (in my ignorance of the sport) that diseasels would be great, even if they wouldn't sound as good! Maybe we could convince Audi to have a go.

Unlimited pullers are cool, but I don't know what they have to do with sportscar racing.

[Hammerdown]

Hmmm! They don't look like internal combustion engines to me! Not sure about the aero treatment either!

[Purist]

Again, what is so "magical" about that 5,000rpm figure? I'm well aware that diesels start up using glow plugs and then rely on sheer cylinder pressure to detonate the fuel during normal operations. (I've listened to "Car Talk" on NPR for years, and my father has been a mechanic for almost 40 years.) Diesels are a type of internal combustion engine, so you're looking at fuel/air mixture, flow, etc indetermining how th engine runs and performs. What I'm getting at is that the componentry (camshafts, crankshaft, etc) and ingredients for combustion (fuel and oxygen) are very much the same between a petrol and diesel engine, so what's the deal with this supposed limit on diesel rpm and performance beyond that rpm?

Now if the fuel's viscosity is the issue in this, we still don't have a conclusive picture of the Audi and Peugeot as the Shell diesel is much less viscous than what you use on the road, or even what the ACO was expecting when they wrote the rules for diesels.

[Bob Riebe]

Originally Posted by Purist

Again, what is so "magical" about that 5,000rpm figure? I'm well aware that diesels start up using glow plugs and then rely on sheer cylinder pressure to detonate the fuel during normal operations. (I've listened to "Car Talk" on NPR for years, and my father has been a mechanic for almost 40 years.) Diesels are a type of internal combustion engine, so you're looking at fuel/air mixture, flow, etc indetermining how th engine runs and performs. What I'm getting at is that the componentry (camshafts, crankshaft, etc) and ingredients for combustion (fuel and oxygen) are very much the same between a petrol and diesel engine, so what's the deal with this supposed limit on diesel rpm and performance beyond that rpm?

Now if the fuel's viscosity is the issue in this, we still don't have a conclusive picture of the Audi and Peugeot as the Shell diesel is much less viscous than what you use on the road, or even what the ACO was expecting when they wrote the rules for diesels.

Go read an article that gives you the exact differences, but until then consider this: If fuel detonates in a gasoline engine, depending on severity, the engine is on its way to destruction.
IF fuel does not experience controlled detonation in a diesel, it ceases to run, so tuning the two, are two entirely different sets of parameters.

[Bob Riebe]

Originally Posted by vorsprung

Unlimited pullers are cool, but I don't know what they have to do with sportscar racing.

It is about engine types.
Some here think a diesel can do anything a gasoline engine can; if that is true unlimited pullers would be using them instead of turbine or gasoline engines.

I used to have the site saved but lost it, but one puller in his class went to to expense of turning his diesel six cylinder John Deere into a gasoline powered otto cycle engine by developing his own four-valve cylinder head, that uses spark ignition for the diesel cylinder block.
OBVIOUSLY, the diesel is lacking in some important performance parameters compared to a gasoline spark ignition engine.
Bob

[gwyllion]

Originally Posted by Purist

so what's the deal with this supposed limit on diesel rpm and performance beyond that rpm?

Diesel fuel self ignites, while petrol is ignited with spark plugs. Diesel get injected at end of the compression stroke and after a certain ignition delay the fuel starts to burn. The ignition delay depends on the cetane number.

This ignition delay limits the rpm for diesel engines. You can not rev higher because the fuel will to ignite in time. With petrol engines you don't have this problem because the fuel gets into the cilinders during the intake stroke (so a lot earlier than end of compression in case of diesel engines) and ignition is started with spark plugs.

[Bob Riebe]

Originally Posted by Hammerdown

With that amount of torque I suppose you don't need so many gears. just as well really, as it seems to be a bit of a problem making them strong enough.

Surprised about the tractors, Bob. I would have thought (in my ignorance of the sport) that diseasels would be great, even if they wouldn't sound as good! Maybe we could convince Audi to have a go.

If you want to see a spectacle that will give greenies a heart attack, go to a pull that uses mod. production diesels.
The smoke is so thick it looks like black clouds.

[henk4]

Originally Posted by Bob Riebe

If you want to see a spectacle that will give greenies a heart attack, go to a pull that uses mod. production diesels.
The smoke is so thick it looks like black clouds.

they should make FAP filters mandatory there as well.....Is there currently any american made diesel car on the US market that is using these filters?

[gwyllion]

[$QUOTE=Purist]Now if the fuel's viscosity is the issue in this, we still don't have a conclusive picture of the Audi and Peugeot as the Shell diesel is much less viscous than what you use on the road, or even what the ACO was expecting when they wrote the rules for diesels.[/QUOTE]As I mentioned in my previous message, viscosity is not the problem. The cetane number of the diesel fuel is.

To give some idea about the cetane of different fuel:

• normal refinery diesel: 45-55 (source); in Europe min 51
• gas-to-liquids: 75-80 (source)
• Shell V-Power Diesel "LM24": 61 (source)

The race diesel fuel from Shell is a blend of normal diesel and GTL diesel.

Such high-cetane blends are commerically available in Europe, but don't have numbers. Examples: Shell V-Power Diesel, Total Excellium, Aral/BP Ultimate.

[chewymonster]

Obviously the tractor guys are running old tech diesels without common rail and piezo injectors. A modern diesels is completely different. And I have seen plenty of diesel tractor pullers.

And you can say that Audi is testing out a new type of fuel.

[HORNDAWG]

Originally Posted by henk4

they should make FAP filters mandatory there as well.....Is there currently any american made diesel car on the US market that is using these filters?

I think the better question is: Are there any American made diesel cars!

L.P.

[henk4]

Originally Posted by HORNDAWG

I think the better question is: Are there any American made diesel cars!

L.P.

I am sure there are at least diesel trucks.....

[JAG]

Originally Posted by HORNDAWG

I think the better question is: Are there any American made diesel cars!

L.P.

There was an advert on TV tonight for a new diesel Jeep.

2.0l, 42 mpg.

[Oldtony]

Now this thread has got away from the noise factor it is bringing out some interesting tech information. So a couple of questions:
1: You would imagine that a deisel would benefit more from a CV gearbox. Has anyone developed one that would be light enough but would withstand the torque? Other than truck units of course.
2: There are some compression ignition engines that have been developed for light aircraft which are designed to run avtur. How does that compare to the Shell VPower etc being used by Audi & Peugot.
An observation based on this thread is that deisel seems more acceptable, particularly in road cars, in Europe rather than in North America. Here in Oz "oilers" only started to become a serious part of the road car market about a year ago, but the changeover is developing the look of inevitability. That is in spite of GM, Ford and Toyota not having offerings. And in spite of the strange situation where distilate is around 10% DEARER than ULP. and around the same price as premium ULP.
Surely racing has to have some technical relevance, although NASCAR and V8SC would indicate otherwise.
By the way if you want to see the future of technology you have to look at trucks. Energy Regen, CV boxes, Turbo compound etc all becoming available.

[Hammerdown]

Originally Posted by JAG

There was an advert on TV tonight for a new diesel Jeep.

2.0l, 42 mpg.

Euro market, made in Austria? They certainly used to be.

And, by the way, one of the most hideously ugly cars I've ever seen. Looks like a 5-year-old's drawing!

[Hammerdown]

Originally Posted by Oldtony

By the way if you want to see the future of technology you have to look at trucks. Energy Regen, CV boxes, Turbo compound etc all becoming available.

24hr truck racing anyone?

Not so sure about the track/road connection. I think that's more marketing guff than real technology these days, but then so is everything!