[DMCForum] Diesels (Was: Re: Electric powered DeLorean)

[Martin Gutkowski <martin@xxxxxxxxxxxxxx>]

Thanks to tax incentives in the last 20 years here in europe, car 
manufacturers have been putting a lot of effort into developing diesels. 
The first real breakthrough was in a car that ironically I've just 
bought again. I drove 200 miles yesterday in a car I won off ebay for £100

This one, to be precise

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=4537934088

This car really put diesels on the map, and the series of 
Peugeot/Citroen XUD diesels spearheaded by this little 1.7 litre 
turbocharged lump could perform on a par with its petrol equivalents and 
return over 60mpg on a long run. The turbo boosts to just over 1 bar and 
it'll do it all day long. This car has done 168,000 miles over the last 
14 years and has had nothing but glow plugs, oil and filter changes and 
cam belts. It goes like a rocket, merrilly wheelspinning in 2nd. They 
are known for the head gasket going but only once every 200,000 miles. 
That I can live with.

The next big jump was with the VW/Audi TDi's which incorporated direct 
injection, but still using a mechanical pump.

The latest generation are the "common rail" direct injection EFI diesels 
like the Peugeot/Citroen HDi's and the Renault DCi's. Some of these 
engines are kicking out over 150bhp from a 2 litre, but inevitably fuel 
economy will suffer.

The basics about diesels are:

1) Diesel fuel holds slightly less chemical energy than petrol. 
Therefore in a 100% efficient system, petrol will be more economical

2) Compression ignition is inherantly more efficient. On the old XUD's, 
the only piece of electrical equipment on the whole car that related 
directly to the engine was the solenoid valve to cut the fuel to turn it 
off.

3) Diesel engines are more noisy at idle, but not at speed. Cite: 
Citroen Xantia 2.0 HDi tested as more quiet in a 30mph drive-by than the 
2.0 16v petrol.

4) Diesels do not kick out CO. However they do put out particulates. 
This is dangerous to humans but totally harmless to the environment. It 
also kicks out Sulphur Dioxide but this is a product of the fuel, not 
the nature of the engine. Biodiesel containes no sulphur

5) The nature of the engines mean they are built stronger and will last 
longer. The output power, hp for hp is almost always lower than a petrol 
equivalent, but it's being shown more and more that the diesel will 
outrun the petrol in any test aside from top speed, and it's all down to 
the TORQUE diesels put out. My Xantia HDi puts out 250Nm at 3000rpm yet 
tops out at only 110bhp.

6) The top speed of a diesel is usually lower simply because of the rev 
range being lower. A diesel will typically red-line at between 
4500-5000rpm. The gearbox is usually tuned to match, and use the torque. 
My Xantia does 3000rpm at 90mph in 5th.

Martin

therealdmcvegas wrote:

>
> Tell me about it. I've been real keen on diesel for a couple of years
> now. I first started looking into it, after seeing a diesel truck hit
> the high 14's in the ¼-mile drag strip. Until that time, I never knew
> that diesel could be so powerful.
>
> The problem here in the US, is that we've not had good experiences
> with diesel vehicles. Diesel trucks/lorrys that haul 80,000 lbs. worth
> of cargo are always slowly lumbering down the road. So people equate
> diesel with slow cars. The same with many of the naturally aspirated
> diesel vehicles that we've seen here too. Like the Daihatsu Charade,
> and the VW Rabbit. SLOW! Plus costs are higher on them, because the
> parts are not as common.
>
> Turbo-charging diesel is good. But only if the moron behind the wheel
> knows how to take care of their car. Back in the late 80's, my aunt
> had a Mercedes Turbo Diesel in California. She never let the car warm
> up, nor did she even idle the turbos down. She ended up coking the
> turbo. But not before it wobbled, and busted off a turbine blade which
> shattered the catalytic convertor. So horror stories like this make
> people think that diesel is inheriently problematic. When in reality,
> it's not.
>
> The image of diesel has not been plesant either. Diesel exhaust has a
> more noticeable smell than gasoline. Not because it's cleaner, but
> because CO doesn't smell. Doesn't mean it safer, or even cleaner. Just
> that it was more noticable. Noise and vibration is a big factor too.
> The old diesels would go "ACK!-ACK!-ACK!-ACK!-ACK!-ACK!" At idle. And
> would vibrate the hell out of the car. Now days, you can hardley hear
> diesel engines idle, and the vehicles don't vibrate any worse than
> gasoline powered ones.
>
> Last Saturday, I went to a car show, where they were dyno-ing diesel
> trucks. This guy had a Dodge 2500 Turbo Cummins Diesel truck on the
> dyno above us (portable one on a trailer). Over 300hp on the dyno, and
> the turbo was louder than the exhaust, with no soot!
>
> The saving grace for diesel in America have been SUVs. People here
> LOVE to drive trucks, that make them feel real powerful. And the more
> they remind them of a semi/lorry, the more they love them. Chrysler
> had a big winner when they relased their redesigned Ram truck in the
> early 90's, because it had such pronounced fenders that were lower
> than the hood, and made it look like a big semi. Now add in diesel,
> and you've got a winning combination. Big-ass truck, with the smooth
> sound of a diesel motor, and people love them. I'm searing for another
> vehicle right now, and have discovered that used diesels now are
> demanding a HUGE premium over their gasoline counter parts. Because
> people are not trading them in.
>
> Diesel here is the same cost are mid-grade gasoline. Whereas
> previously, it was cheaper than low-octane gas. Give it time, and
> we'll all be running diesel in our trucks in a few years.
>
> -Robert

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