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From: Bod on 19 May 2010 12:02 Adrian wrote: > Bod <bodron57(a)tiscali.co.uk> gurgled happily, sounding much like they were > saying: > >>>> Like I said... >>>> >>>> <sigh> >>>> Stochiometry is normally 14.7:1. >>>> For the Ricardo lean-burn, it was up around 21:1. Pro: Superb fuel >>>> economy, no loss of drivability. Con: NOx way, way higher. > >>> Its still not as efficient as a diesel of the same size because a >>> diesel is essentially a lean burn engine anyway in the sence that its >>> throttled by the amount of fuel injected , not by a throttle valve. > >> Aren't most petrol engines 'fuel injected'? > > Yes. > > However, on a petrol engine, both fuel and air are controlled. A diesel > is controlled only by varying the fuel - the air is unthrottled. > > Bloater seems to think this is somehow relevant to lean burn petrols. God > knows why. He also seems to have redefined "efficient" again, since a > Ricardo lean burn would have been way ahead of both contemporary diesels > and modern common rails, if mpg is the only metric required. > > Oh, right. Bod
From: boltar2003 on 19 May 2010 12:05 On 19 May 2010 15:51:39 GMT Adrian <toomany2cvs(a)gmail.com> wrote: >Bloater seems to think this is somehow relevant to lean burn petrols. God Because a lean burn engine basically gets rid of throttling losses so is more efficient at lower rpm when the throttle would otherwise be partially closed. >knows why. He also seems to have redefined "efficient" again, since a >Ricardo lean burn would have been way ahead of both contemporary diesels >and modern common rails, if mpg is the only metric required. For the same power output? Got any proof of that? B2003
From: GT on 19 May 2010 12:08 <boltar2003(a)boltar.world> wrote in message news:ht0sd9$232$1(a)speranza.aioe.org... > On 19 May 2010 13:00:28 GMT > Adrian <toomany2cvs(a)gmail.com> wrote: >>> No, I was simply talking about mpg which I don't think is a "vague" >>> measure of efficiency. >> >>Lean-burn. Ricardo. Discuss. > > A dead technology for cars. Discuss. Not dead. Used on Alfas for the last few decades. My 156 runs in leanburn below 1500 rpm. Ideal for city driving and occasional stationary moments!
From: Adrian on 19 May 2010 12:16 boltar2003(a)boltar.world gurgled happily, sounding much like they were saying: >>Bloater seems to think this is somehow relevant to lean burn petrols. > Because a lean burn engine basically gets rid of throttling losses so > is more efficient at lower rpm when the throttle would otherwise be > partially closed. ITYM "diesel". Lean-burn petrol is still throttled in the usual way - although not all petrols are, look at BMW's ValveTronic.
From: Adrian on 19 May 2010 12:18
"GT" <a(a)b.c> gurgled happily, sounding much like they were saying: > Not dead. Used on Alfas for the last few decades. My 156 runs in > leanburn below 1500 rpm. Ideal for city driving and occasional > stationary moments! Is that intentional, though, or just another Spaghetti Marelli bit of "character"? (I had a 155TS and a 75 v6, and loved 'em both) It's not the full-on Ricardo lean-burn, though, just "not quite as rich" - and the requirement to keep lambda to damn near one is really only because of three-way cats. Full power is developed richer, and leaning off is eminently possible otherwise, for greater economy. But - of course - Bloater will poo-poo what he doesn't understand. As ever. |