DIY_EFI Digest Wednesday, March 29 2000 Volume 05 : Number 128 In this issue: Re: Measuring weight Re: O2 sensor response times - cleaning ? Re: Looking for pulse output MAF Re: Cheap Protection ... The circuit Re: O2 sensor response times- catalyst Re: Cheap Protection ... The circuit Re: O2 sensor response times- catalyst Aftermarket ECU & RT OS 8051 EFI code See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 28 Mar 2000 18:46:55 +0100 From: Ade + Lamb Chop Subject: Re: Measuring weight At 01:00 28/03/00 -0600, MysticZ wrote: >Ade + Lamb Chop wrote: >> >> That is exactly what most digital scales do. My mum has a pair of >> digtal bath room scales. > >Hmm... I have a digital scale that doesn't work worth a damn anymore. >Perhaps I should dismantle it and see how it works... Then throw the >corpse in the pile with the scavenged alarm clocks and hard drives ;) I the ones I have seen use load cells. They are a bar which (I think) when bent o/ps a small voltage like thermocouples do. Ade - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Tue, 28 Mar 2000 23:12:49 -0700 From: "derek barger" Subject: Re: O2 sensor response times - cleaning ? What I do when an 02 sensor is fouled by contaminants is to remove the sensor and heat with propane torch. Heat with propane torch for 30 secs then remove let cool. While you are doing this attach a meter to O2, watch voltage heat and remove watch voltage swing and response time from 1volt to 0. >At 05:35 PM 27/3/2000 -0800, Orin wrote: >>Heywood pg 301: "Equilibrium is established in the exhaust gases >>by the catalytic activity of the platinum metal electrodes." > >mmmm Just a thought, > >Is there any chance a 'hot purge' in fre O2 at high temp can 'flush' the >sensor ? > >ie. Remove sensor from exh manifold, put in oven with liberal feed of pure >O2 and heat to exhaust temp for a period of time, perhaps cycle through >temp range whilst flowing o2 over it... > >I'm guessing this might flush out some/most contaminants - anyone in a >position to try this - or interested ? > >I wonder if someone has an oxy torch, can make up a little pipe, close off >the end, heat it with the oxy (not too hot), fill the pipe with O2 from >the oxy tank and let it cool down filled with pure o2 ? > >Rgds > >:) Mike > >--------------------------------------------------------------------------- - - >To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) >in the body of a message (not the subject) to majordomo@xxx.org > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 2000 01:54:24 -0500 From: "nacelp" Subject: Re: Looking for pulse output MAF Ya generally need 1.3 grams/sec per HP. so you need something about 290ish grams/sec. Which is right on the middle of nowhere, of what I'm familiar with. However, using a late model v-8 MAF (3.0") should be in the right neighbor hood. ie 96 and later. I think they were up to 400 grams/sec.. Least you'd get to have too much range.. How could you build the box, without knowing the frequency range?. Grumpy Can I see the diagram?. > I'm looking for a GM MAF (pulse output) that can handle the flow > from a 4.0 liter motor (approx 220hp). I've already built the pulse to > AFM conversion box so I need to use a pulsed sensor. The sensor > I've got now (I got it from the U-pull-R yard out of a 2.8l chevy) can't > handle the flow rate. Any help is appreciated. > Brian - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Tue, 28 Mar 2000 23:24:24 PST From: "mike mager" Subject: Re: Cheap Protection ... The circuit > http://www.perth.dialix.com.au/~bernie/tech/LW.pdf The hyper link completely stalls my computer; I understand PDF; is the file enourmous, or is there some reason that it won't just 'pop' into an Acrobat Reader window (allowing time for download)? I can (and did) access the site, no problem, but I saw no link to the PDF file. Thanks, Mike >From: Bernd Felsche >Reply-To: diy_efi@xxx.org >To: diy_efi@xxx.org >Subject: Re: Cheap Protection ... The circuit >Date: Wed, 29 Mar 100 11:17:14 +0800 (WST) > >Thanks for all the hints and comments on the means of protecting >inputs. > >The first draft of the circuit schematic can be found at > http://www.perth.dialix.com.au/~bernie/tech/LW.pdf > >I've done a few trial layouts and the components "fit" easily on a >50mm-square single-sided PCB with only two air-wires. > >It's not yet a working design; still need to check on how to drive >some sort of audible warning (at the moment I'm using a "spare" >buffer on to 4050), to confirm the driving of the FET (which will be >PWM), and to finalise values for the input filter caps and >resistors. > >-- >Real Name: Bernd Felsche > Email: nospam.bernie@xxx.au > http://www.perth.dialix.com.au/~bernie - Private HP >---------------------------------------------------------------------------- >To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the >quotes) >in the body of a message (not the subject) to majordomo@xxx.org > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 2000 12:10:35 +0200 From: "Espen Hilde" Subject: Re: O2 sensor response times- catalyst I am just guessing here but I think its something we are missing. When there is o2 in the exhaust we dont have to "pump" at all? Maybe the thing is to measure the wide band in 2 ways to get the wide range, first as a usual o2 sensor giving mvolts and swich to current when over the stoic aria. Espen > >>Just for anyone interested, in the NTK wide ratio sensor manual it > >>states that the O2 "pump" current varies from -12.5 to 12.5 mA, the O2 > >>sensor is biased with a 25 uA +/- 3 uA current (the sensor output > >>voltage (450 mV for stoich) is read on top of that). The heater > >>voltage is 10.5 +/- 0.5 volts. I still don't know how you go from > >>pump current to AFR! > > > >This is derived from the new Bosch SI Engine Management book: > > > >The -25 mA would correspond to approx lambda of 0.7, +25 mA to > >approx 2.2. 0 mA is lambda = 1. > > > >You should be able to fit a curve through those three points. > > > >Not that it's not often useful to have a lambda of 0.7 - that's way > >more rich than any steady-state running would require. > > Argh. All I'm at liberty to say to the immediately above is "BZZZT". > Remember I warned ya, these devices are both spendy and VERY easy to > destroy by over-pumping or mis-pumping (pumping in the wrong direction). > It's referred to in the trade as "blackening" the sensor. Others who > have worked with these sensors in industry and have no commercial > interest in them as I do, will also confirm this. I shit you not. > Besides, I'm surprised that a Bosch book would even mention an NTK > sensor, but those numbers aren't even close. > > BTW, 0.7 lambda is roughly 10AFR. WOT turbo engines can/will fuel in the > 10'sAFR during transient enrichment under heavy load, so altho this > isn't "steady-state running", being able to see and measure these rich > excursions isn't so far afield. And carb'd engines will lean-misfire and > even backfire, if idle-jetting combined with a rapid undamped > throttle-off runs the AFR to above 17-18, so measuring to this lean, > again altho not "steady-state" still can be important, too. > > I won't be saying too much more about tech stuff concerning these > sensors; as an instrument vendor I'm just not able to participate the > way I'd like to, without raising suspicions of bias. C'est le vie. Just > caveat your emptors, doods, and save at least one good, pristine, > virgin, unmangled sensor for EGOR, will ya? > > TTFN, > Gar > > > - ---------------------------------------------------------------------------- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 100 18:50:42 +0800 (WST) From: Bernd Felsche Subject: Re: Cheap Protection ... The circuit mike mager writes: >> http://www.perth.dialix.com.au/~bernie/tech/LW.pdf >The hyper link completely stalls my computer; I understand PDF; is the file >enourmous, or is there some reason that it won't just 'pop' into an Acrobat >Reader window (allowing time for download)? It's only about 56 kbytes. I thought that better than 450kb of Postscript... >I can (and did) access the site, no problem, but I saw no link to the PDF >file. No link at all to that file. (You can't read the directory either because if I had secrets, I wouldn't want you to know that I have :-) OK... I've taken mercy on you and added in the link on http://perth.dialix.com.au/~bernie/ Under Technical Articles. If your network bruiser can't handle it automagically, then use either the right mouse button options to download the file or a shift-click usually does the job. I can even download it with lynx. No Problem. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 100 19:30:16 +0800 (WST) From: Bernd Felsche Subject: Re: O2 sensor response times- catalyst Garfield Willis writes: >On Wed, 29 Mar 100 10:22:49 +0800 (WST), Bernd Felsche > wrote: >>Will McGonegal writes: >>>Just for anyone interested, in the NTK wide ratio sensor manual it >>>states that the O2 "pump" current varies from -12.5 to 12.5 mA, the O2 >>>sensor is biased with a 25 uA +/- 3 uA current (the sensor output >>>voltage (450 mV for stoich) is read on top of that). The heater >>>voltage is 10.5 +/- 0.5 volts. I still don't know how you go from >>>pump current to AFR! >> >>This is derived from the new Bosch SI Engine Management book: >> >>The -25 mA would correspond to approx lambda of 0.7, +25 mA to >>approx 2.2. 0 mA is lambda = 1. >>You should be able to fit a curve through those three points. >>Not that it's not often useful to have a lambda of 0.7 - that's way >>more rich than any steady-state running would require. >Argh. All I'm at liberty to say to the immediately above is "BZZZT". Thought you might. :-) I didn't put a big disclaimer on there to save on mail volume. You've already distrivuted the huge caveat. Why repeat it? >Remember I warned ya, these devices are both spendy and VERY easy to >destroy by over-pumping or mis-pumping (pumping in the wrong direction). >It's referred to in the trade as "blackening" the sensor. Others who >have worked with these sensors in industry and have no commercial >interest in them as I do, will also confirm this. I shit you not. >Besides, I'm surprised that a Bosch book would even mention an NTK >sensor, but those numbers aren't even close. It's the latest book. The book doesn't provide the numbers, other than the lambda range and the characteristic curve. The current values are from the data sheet. Is the NTK any different to the Bosch wide-range lambda probe? Both use the pump current to indicate the AFR. Both use a reference cell against which to balance O2 concentration. As you say; one should be very careful when playing with these things. Even a switching lambda probe can be destroyed by shorting the terminals or by using a low-impedance load... >BTW, 0.7 lambda is roughly 10AFR. WOT turbo engines can/will fuel in the >10'sAFR during transient enrichment under heavy load, so altho this >isn't "steady-state running", being able to see and measure these rich >excursions isn't so far afield. And carb'd engines will lean-misfire and >even backfire, if idle-jetting combined with a rapid undamped >throttle-off runs the AFR to above 17-18, so measuring to this lean, >again altho not "steady-state" still can be important, too. Why would you deliverately put in so much excess fuel? It takes you right off the power curve peak. The only scenario I thought of beforehand was during cold cranking, so that you can light the mixture. The O2 sensor probably won't be hot enough to work from a cold start - unless you've flooded the engine. :-) >I won't be saying too much more about tech stuff concerning these >sensors; as an instrument vendor I'm just not able to participate the >way I'd like to, without raising suspicions of bias. C'est le vie. Just >caveat your emptors, doods, and save at least one good, pristine, >virgin, unmangled sensor for EGOR, will ya? Good advice. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 2000 12:19:23 +0100 From: Corner Paul Subject: Aftermarket ECU & RT OS Hi Randall Have you looked at Linux - there are Real Time patches available. Regards, Paul - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Wed, 29 Mar 2000 12:33:12 +0100 From: Corner Paul Subject: 8051 EFI code Hi John Any chance you would like to share the algorithms or some of the source code ? I've looked at Al Lipper's work - the core routines aren't that different to what I had allready coded. Regards, Paul. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #128 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".