Thankfully for the time being B20 is the most likely blend for general use. Further down the road, I think all Euro cars will have no NOx catalysts. The ultra ultra low sulphur fuels now make them viable. It's sad though that high tech, high cost systems using rare noble metals have to be used to solve the problem.
On TDIs, the injection pump is mounted on slotted holes like a petrol distributor, this allows it to be moved a little about it's drive shaft. On PD and common rail setups the pump is just a pressuriser, I guess the pickup used by the electronics to detect crank position is fixed, but it just might be on slotted holes. I wonder if the PD/common rail electronics are clever enough to adjust the injection advance according to peak cylinder pressures. I'll bet they already adjust it according to speed. Dave --- In [EMAIL PROTECTED], Keith Addison <[EMAIL PROTECTED]> wrote: > Hi Marc, David and all > > >100% bio with slightly retarded injection timing will also reduce > >NOx. The higher cetane value of bio means the combustion chamber > >pressure rises faster and more reliably so can deal happily with less > >advance. > > Yes - so who needs additives? Though I noticed that NOPEC also uses > an additive for low-NOx. There are some interesting findings here: > http://journeytoforever.org/biodiesel_nox.html > > Including this one: "I have certified emissions for the urban bus > retrofit program with EPA (US Environmental Protection Agency) using > this technology. This package included use of an oxidation catalyst > to maximize Particulate Matter (PM) reductions (taking advantage of > the high soluble organic fraction of biodiesel) and a timing change > to give up some PM reductions while reducing NOx to baseline or even > past baseline -- the best case was a 28% NOx reduction with a 25% PM > reduction." > > One point though - someone asked how you go about retarding the > ignition timing on a new-model diesel where everything's computer > controlled. I don't know from computer controls (25-year-old Land > Rovers), didn't know how to answer. Any ideas? > > >I think a B20 blend gives no more NOx than 100% fossil, is that > >correct? > > I think so. > > That's nice information below Marc, thanks. > > Best > > Keith Addison > > >Dave > > > >--- In [EMAIL PROTECTED], "F. Marc de Piolenc" <[EMAIL PROTECTED]> wrote: > > > > > > Keith Addison wrote: > > > > > > > ASomeone's been trying to sell me on an additive > > > > to reduce NOx. Apparently it does indeed reduce NOx, and > > > > simultaneously CO, but otoh I think NOx is an overblown problem, > >I'm > > > > always a bit suspicious when people chuck the NOx objection at > > > > biodiesel. Better to debunk the thing rather - "solving" it via an > > > > additive lends it too much credence: ie, biodiesel ain't no use on > > > > its own unless you use an additive. > > > > > > Correct. NOx is not caused by high combustion temperatures, but by > > > "crevice combustion" - combustion in tight spaces with a high ratio > >of > > > cooled perimeter to volume - which entails rapid quenching and > > > "freezing" of the back-reaction which otherwise converts NOx back to > > > free nitrogen and oxygen. Southwest Research Institute proved this > >at > > > least twenty years ago, in research sponsored by DoE. I read the > >report > > > that long ago, and it could have already been some years old at that > > > time. > > > > > > What this means is that NOx is a combustion chamber and piston > >design > > > problem; SRI showed that relatively minor changes in piston crown > >design > > > reduced NOx significantly in their test engines. > > > > > > Leaving out crevice combustion, diesels should have lower NOx > >emissions > > > than spark-ignition engines because their pressure "spike" is not as > > > pronounced. > > > > > > Marc de Piolenc Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://www.webconx.com/2000/biofuel/biofuel.htm To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
