VW TDIs 90 and 110 can be adjusted and are electonic. Inj pump is Bosch sorry don't know the model #.
They started making TDIs around 93 or 94 I think initially in Audi A4s. My 95 Passat has no accelerator cable (diesels don't have a throttle either) just a potentiometer under the pedal. electronics manage everything except the basic injection timing. I don't know if there is any advance/retard adjustment within the pump to alter timimg according to engine speed. The Bocsh inj pump is visually much like any other with ditributor pipes out to each injector. However it has no mechanical linkage just a black box on the side. Computer is elswhere away from heat and damp. Bosch supply most motor makers so the same basic injection system probably appears all over the place. The new VW PD (can't spell Pump Deuce) has everything incorporated into each injector and is fully electronically controlled. Common rail systems also do all the injection timing electronically. These only came in within that last couple of years or so. TDI injectors cost loads. Goodness knows what the bill for new PD unit or common rail injector will look like. --- In [EMAIL PROTECTED], Keith Addison <[EMAIL PROTECTED]> wrote: > >it's not ignition timing (diesel's don't have "ignition"), it's injector > >timing, and most diesels are mechanical injection, although I have not > >worked on any post 1990 diesels, which may be electronic. > > Hi Steve > > Of course yes - sorry, slip of the, er, mind... It was a post-90 job > the guy was talking about. > > Thanks > > Keith Addison > > > > >Steve Spence > >Subscribe to the Renewable Energy Newsletter: > >http://www.webconx.com/subscribe.htm > > > >Renewable Energy Pages - http://www.webconx.com > >Palm Pilot Pages - http://www.webconx.com/palm > >X10 Home Automation - http://www.webconx.com/x10 > >[EMAIL PROTECTED] > >(212) 894-3704 x3154 - voicemail/fax > >We do not inherit the earth from our ancestors, > >we borrow it from our children. > >-- > > > >----- Original Message ----- > >From: "Keith Addison" <[EMAIL PROTECTED]> > >To: <[EMAIL PROTECTED]> > >Sent: Tuesday, July 10, 2001 1:01 PM > >Subject: Re: [biofuels-biz] Additives > > > > > > > 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/
