Doug Coulter wrote:This I can believe. Around here the people that get any diesel mostly get these honking huge trucks (the kind you don't have to bend over far to see under) -- maybe they have "real trucker" envy and do like they do - the tractor trailer guys leave theirs running for various reasonably good reasons.
I used to drive Articulated trucks. A 'side' job while I was studying at University.
So I can definitely speak from experience;
The only reasons for leaving a truck's engine running are;
a) you think your battery or starter motor are on their last legs - in which case, the vehicle is unroadworthy, get it off the road and fix it
b) the air tanks are losing air too quick - in which case, the vehicle is unroadworthy, get it off the road and fix it
The only 'legitimate' occasions to leave an engine running are;
1) it is -20C and you want to keep temperature in the engine to avoid fuel waxing
2) You've just been running it hard down the highway and you come to a dead stop from high speed, in this case it is reasonable to want to circulate coolant for 2 minutes to avoid hot-spots in the head
3) You have a turbo or supercharged engine (diesel
or petrol) that has been running fast in the preceeding minute and you let it run on for 10 seconds so that the turbo can spool down, and that oil doesn't carbonise up in the lubrication channels within the turbo/supercharger (because it is at exhaust temp).
There's no reason to let an engine run on indefinitely, Doug, big truck or little car. It is just plain old flat-out ignorance.
I'd kind of have to agree with you about hybrids except for one thing -- sometimes the extra peak power at the wheels IS nice, and if designed right, it's there when you need it with a pretty small motor and battery (if the real engine is also there).
Yes, I don't have a downer on hybrids, simply that they are tuned to to a certain job. And if you do not require it to do that job, then all you are doing is lumping around a heavy motor, or 4, and a set of batteries. Most hybrids are tuned to do well in the official fuel consumption tests, and that is all they are good at doing. If you drive as if you are doing Gov approved drive cycles, then you'll do well with it.
I, on the other hand, drive for 10 mins out of town and have the route sussed out sufficiently well that I barely touch the brakes. Then onto the motorway. I have no opportunities to 'recover' any braking energy, so a hybrid would be of no value to me.
Now if we could get diesels to not sound like they're gargling rocks at idle....I'd be happier (couldn't you squirt the fuel in slower?).
Again, you need to comprehend where Europe is with diesels now. They are so quiet I can barely believe it myself now. If someone gives me a lift in a new car, you really have to ask whether it is diesel or petrol.
Actually, it is quite the opposite of what you just said. The latest injection systems operate at around 2,000 bar pressure and use piezo systems that allow a series of pre-injections before the main fuel pulses. This smooths out the combustion noise. You might get 5 pilot injections, a mid-injection and then a couple of main injections, for each stroke. Further, as these engines have evolved, the way the 'deck' design of the block and the way they are re-enforced internally makes them tuned to reduce external audible radiation from the block surface. The turbo (all diesels have turbos now, some have two) smooths out the exhaust so there is essentially no exhaust note. The main noises are from the induction system (but again smoothed by the turbo and, probably, intercooler matrix) and direct radiation from the top of the cylinder head.
I assure you, if you were to buy a petrol and a diesel of the same model somewhere here in Europe tomorrow, you would struggle to tell the two apart on the noise quality.
I don't think we get as much of the sulfur removed from the fuel here - in fact, that's the reason Europe was using Libyan crude - low-sulfur right off the boat. BTW, the beemer is a diesel. Not that I'll be able to afford one.
Yes, big issue. And one, indeed, that has kept Euro diesel tech at arms-length in US. You don't get all this high performance on shyte fuel!
With this odd variable timing capacity, the ecotech engine runs at 13:1 compression on gasoline, regular. They just adjust the cam timing so that when slow, it doesn't reach full compression, but going fast, it has over 100% volumetric efficiency (and then add the turbo). At high enough revs, detonation doesn't have time to happen, so you can get away with it. So that's getting right up there with a diesel in compression efficiency (though it does spin a lot faster) re thermodynamics.
Indeed there are ways to get petrol cars up to somewhere near diesels. You might also note that if you drive a petrol and a diesel flat out, then you'd probably not see that much difference either. This is because one of the advantages of diesels is zero pumping losses. In a petrol where you have a vacuum in the intake, to maintain a lower pressure of flowing gas requires power, these are termed 'pumping losses'. Diesels have no throttles (well, need no throttles, some put them in just to generate vacuum, which costs fuel economy). So run a petrol fully open and then the only delta is the combustion temperature. (Carnot and all that).
The thing is, yes, folks keep pushing petrols upto diesel efficiencies, then diesels efficiency gets pushed up further still. Diesel will always top the efficiency thing. It's like asking who is the stronger, men or women. For sure, there are plenty of women stronger than I am, but if you wanted to train up 'the strongest person' you'd pick a man (not me - pick a good candiate to start with!) to train up. Diesels are 'men' engines, petrols are 'women' engines!