what is diesel?

[Golf Loon]

Calling Sharky. Come on then, tell us your performance figures.

All you diesel blokes know them!

[imported_brackie]

"Diesel is the wave of the future, don't let those petrol guys flick you any poop about compression ignition. Petrol performance is played out and we get to be on the leading edge of diesel performance tuning while achieving awesome fuel economy. Best of all, we can be fueled by clean-burning, renewable Biodiesel. The VW platform enjoys plenty of aftermarket parts for suspension, apperance, and power. Take it to the top!"

Strong words! Better visit his website or PM him for performance figures. Also go to http://vwdiesel.net/phpBB/index.php where you will be amazed at what these guys get out of their diesels. Mr Sharkey is heavily involved with this site and you can pick up his posts and visit his pages on EVs etc.

[GoLfMan]

so do bio diesels use re newable fuel??? i wanna run my car on ethanol but it was $2.40 a litre

[imported_brackie]

Biodiesel is just that! Diesel made for animal or plant oils. Bio=life, so as long as you grow plants or animals and convert free solar energy into chemical energy that can drive a diesel engine, it's renewable. (In truth, crude oil is also made for animal or plant oils but because the organisms lived in the Mesozoic and are long gone, the energy isn't renewable.) So petroleum ("of the rocks") is a finite resource and once it's gone....its gone. Biodiesel, however is not finite. As long as the sun shines and the plants take in carbon dioide and water to convert solar energy into chemical energy it is infinitely renewable. The challenge for our species is to breed plants that can produce more oils than they currently do. If we can do that (without, hopefully getting into GM) then we can run our diesels as long as the sun shines and the rain falls. Oh...And the best thing about biodiesel is that the plants recycle the carbon dioxide and water vapour produced by combustion...so we don't pollute as much as petrol engined cars.

[GoLfMan]

bio diesel, ethanol, hydrogencompressed natural gas are all the ways of the future i think. no longer will we have to rely on one fuel source for the world. if we have more than one fuel source then the demand and strains on any one fuel source will be more evenly spread and easier to handel.

[imported_brackie]

No...I'm not a "doom monger"! And yes, I did see the "Mad Max" movies, but ths article is really scary. Lots of reading (took me 2hrs but I read it very carefully) but I can (to the limits of my knowledge) verify the scientific/economic content as being true.
As far as the "Peak Oil" normal distribution curve is concerned, remember that because of the developing third world (particularly China) oil consumption is growing way faster than production, and the downside of the curve will be much steeper. Second page is much larger than first page, but the geopolitical ramifications and the way in which it explains the policies of the Bush administration(s) is revealing. Even if you don't want to read it all, the section on biofuels is a real dampener. I'm going to leave this post here for a couple of days and them move it to "Interesting Articles". Because it will have a "Sticky" there it'll be very interesting to return to it in future years and see how accurate the predictions have been. Some of you may think something like this is a little "heavy" for a car forum, so you can ignore it if you like!

http://www.lifeaftertheoilcrash.net/

[Sharkey]

Hey Guys;

Pretty much everything in this thread is accurate factually. Diesel engines have a natural advantage over petrol partly because they (or most of them, all VW’s anyway) don’t have a throttle plate to restrict the volume of air entering the engine. In a petrol engine, much power is consumed in “pulling loss”, the pistons attempting to pull air past the throttle plate, which during most driving is partly closed. Diesels run the intake wide open, meaning that the piston experiences much less reluctance in pulling in air. This is the reason that diesel engines don’t have any intake vacuum to speak of.

Petrol engines depend on a very narrow range of air-to-fuel ratio, nominally 13-to-1, and the throttle pate is there to regulate the amount to air that will be required to combust the quantity of fuel needed to achieve the level of power required.

Diesel engines run a wide range of A/F ratio, as low as 200:1 at idle and approximately 20:1 at WOT. This is possible because instead of attempting to ignite the A/F mixture with a spark plug (requiring the 13:1 A/F), the fuel is atomized into the cylinder at TDC in a timed injection window. The extreme heat generated by the high compression ratio (23:1 in IDI diesels) is above the flash point of the fuel, it has no choice but to ignite and burn.

The rattly/knocking that you hear in the diesel is the result of the cylinder peak pressure at ignition. In the newer TDI engines, a two-stage injector is used to minimize the peak pressure and lessen the noise.

About my diesel hybrid:

I had very high hopes that the electric Golf when coupled with the diesel pusher trailer would get astounding fuel economy. The reality is that I get about what you’d expect from a petrol Golf, 25-30 MPG (convert to Km/l yourself). This isn’t all that awful of you consider that I’m hauling around two aerodynamically-challenged auto bodies, with two transaxles (one an automatic transmission), six tires on the road, and a total weight of around 2000Kg. The economy is about what you’d expect from a diesel vehicle of this weight, maybe a little better. The EV/Pusher combo does follow the hybrid model, with electric/ICE drives complementing each other under various driving conditions.

A diesel hybrid may not give as much benefit as a petrol hybrid because the torque specifications of electric/petrol are better. The petrol engines don’t have as much low end torque, which the electric drive makes up for. Diesel hybrids have two drive systems with lots of low end torque, so the benefits aren’t as complementary,

Also, petrol hybrids are putting a tiny ICE in the car and making up for its inadequacies when more power is needed with the electric drive. A petrol engine run at WOT is actually most efficient as the throttle plate is not as much of a factor in efficiency, so a small engine running flat out will give the best mileage., but not have enough power for passing and hills.

A diesel running flat-out is about the same efficiency as one running at a lower “throttle” setting (being asked to produce less power), so putting a tiny diesel in a hybrid doesn’t give any better efficiency than putting in one that can produce all the power the vehicle needs, but not calling for it unless needed.

Finally, yes, I agree, the petrol “Hybrids” are a crock of goat dung. Not all that much better mileage, ~and~ you can’t fuel them with 100% renewable fuel. You can’t even plug most of them in to charge the batteries; all of the power comes from the petrol. That’s not a hybrid. “Hybrid” means “powered by more than one source of fuel”. At least my hybrid meets those criteria!

I don’t get on here much (oh, no, another forum to follow), but I’ll try to frequent more in the future.

[Golf Loon]

That Hybrid thing is mad. I bet you get some stares dragging that around.

[gldgti]

I guess the other option is diesel electric......thats anoter story.

i wanted to input a small comment on oil production - as was mentioned further up the page.

renewable oil production is the biggest factor keeping bio diesel from becoming the next crude i guess, because you need so much land to produce oil from crops like canola or oil palms, olives, cottonseed etc etc etc.

one producer of oils that is seldom mentioned is algae, notably decendants of the algae that made oil millions of years ago.

some algaes when grown in a controlled, farmed environment have been shown to be up tp 90% oil. whats more, many of these algaes will grow in lukewarm, salty water, under plastic in direct sun, with some osurce of nitrogen (sewerage) in the water..... see where i'm heading?

a place like australia, with plenty of sunshine, flat land, and a sewerage supplying civilization, would be an ideal place to grow some of these algaes, which can produce 60-70 times the oil per unit area than a crop like canola.

there is research being done in this area, and i'm certainly no expert in it. my dad is very interested in it, so thats where most of this info has come from, but you guys should know this stuff - you never know when youm ight be offered shares in a struggling company that says they want to grow algae on our sewerage....

[imported_brackie]

Yeah, the majority of crude oil deposits are algaeic in origin. The algae accumlated, were heated and forced to give up their oil, which then migrated through porous rocks until it was trapped by some structure. Modern marine algae are very similar (in some cases identical) to their ancestors and have the potential (as you say) to produce useful amounts of oil. The problem, however, is the scale at which this must happen to make it economically viable. Mesozoic oil deposits were formed in vast areas of sea water over millions of years. Most planktonic algae are pelaegic (they live in the photic zone near the sea's surface) so you would need salt lakes on a gigantic scale to produce enough oil to replace a country's diesel consumption. Not that this couldn't be done, but the shallow water would have an enormous amount of evaporation, so the lakes would have to be near the ocean in order to replenish them. The addition of nitrogenous waste would have to be very carefully controlled as it may eutrophy the water to the point where blue-green algae (cyanobacteria) would take over.

Overall, an excellent idea! (I've been out of Geology for a while so my memory may have failed me as I wrote the above. Other scientists...please feel free to correct me!)