DIY_EFI Digest Sunday, 15 September 1996 Volume 01 : Number 274 In this issue: RE: MAP sensor Re: water injection Re: Re[2]: O2 Sensor-Leaded gas Re: Math Question Timing - again Re: MAP sensor Re[2]: Re[2]: O2 Sensor-Leaded gas Re: steam! See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: acazin@xxx.com Date: Sat, 14 Sep 1996 11:07:53 +0000 Subject: RE: MAP sensor > Now, the frequency output of the OEM unit -- seems that > that would entail either an F-V convertor and then A-D or an > interrupt driven timer circuit that would return a number of counts > proportional to the period of the sensor output. Any suggestions? Expect the Ford MAP to be a few $ more than a GM or Chrysler MAP. But the digital output means that it can be processed by the microprocessor directly, without A-D conversion. So, if your control module can accept the signal, this signal is ready for consumption. You could probably buy the sensor from a junk yard (I don't recommend it), to save a few $, but if you do, check it for proper operation. Use a hand held vacuum pump, give it 5V and ground, and measure the frequency output (on the center wire of the connector) from 0 in. to 25 in. of vacuum, in 5 in. vacuum intervals (ie. 0, 5, 10, 15, 20 , 25). Then, graph the freq. vs. vacuum and you should get a straight line (a little drifting is OK.) Also, tap on the sensor and maybe heat it to see if "it gets lost". If it passes these simple tests, then the sensor is OK. Alex Cazin ------------------------------ From: Arnaldo Echevarria Date: Sat, 14 Sep 1996 12:03:48 -0400 Subject: Re: water injection >The full description of his results can be found in the fourth edition of >Sir Henry Ricardo's "The High Speed Internal Combustion Engine" >pages 165-171. (only in the fourth edition) > Someone (is it you) keeps quoting this book and I can't seem to find it. I've looked everywhere in Orlando, Fl with no luck. Any ideas? Arnaldo E. ------------------------------ From: Darrell Norquay Date: Sat, 14 Sep 1996 11:44:14 -0700 (PDT) Subject: Re: Re[2]: O2 Sensor-Leaded gas At 01:57 PM 9/12/96 -0400, you wrote: >Come on guys.... that's why I made the archive searchable >through http://efi332. Do a subject search for "lead" and the >whole thread is there! It took several days to put the search >engine and html stuff together.... USE IT! :) > > John S Gwynne > Gwynne.1@xxx.edu Thanx, John. Could you maybe put a reminder about this in the monthly subscriber thingie, just for da halibut? regards dn dnorquay@xxx.com ------------------------------ From: Dirk Wright Date: Sat, 14 Sep 1996 15:23:28 -0400 (EDT) Subject: Re: Math Question On Fri, 13 Sep 1996, Robert J. Harris wrote: > The point was, is, and always will be to try to combine the sheer power of > a steam engine with the simplicity of an IC engine. The use of a > locomotive > was to illustrate the power available from steam and small cylinder's not > to > spend my life re-hashing ancient history. Isn't that part of the advantage of water injection? Add some water to the combustion process, make some steam, get more cylinder pressures? I know that water injection in avaition is mostly used during takeoff to prevent detonation, and thus allow an A/F ratio that produces maximum power, but an aviator friend of mine said you get some of the added kick of a steam engine. He also said engines running water injection run smoother, too, even under partial load conditions. > **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: talltom Date: Sat, 14 Sep 1996 12:30:13 -0700 (PDT) Subject: Timing - again Well it's time for me to challenge some with more edu than me, but I'm armed now! Awhile back there was a thread about timing with various and asundry theorys about what exactly takes place in combustion chamber, what preignition is, detonation etc. Ed and Todd both described scenarios designed to set timing to avoid knock. I've maintained that some combustion chambers aren't inclined to knock and are best timed by power. My expierience with these(Fiat and some fe series Fords come to mind) suggests that power goes down significantly before knock, and frequently is accompanied by surging. While it doesn't show to a great extent, the latest Circle track Magazine has dyno tests on the latest Ford heads that show that timing is best at some point well behind the knock point. I manintain that much bigger differences than show here are available in the real world.(on track) Having blown engs using the knock method, it leaves me a little less than impressed. It still seems that the trick is finding the sweet spot, with knock only useful for a message telling you which way to go, and that you need to go a ways. Anyhow, do any of you guys that know about combustion chamber design want to see if you can agree on why this is? No, I'm not going to argue with you, just watch the proceedings. Ps. I got another bosch d brain brain and it works.(I'm back to a v8 now!) Can anybody tell me the difference between bosch #0 280 002 013(original) and the only thing I could get to replace it #0 280 002 005? ------------------------------ From: Darrell Norquay Date: Sat, 14 Sep 1996 12:51:03 -0700 (PDT) Subject: Re: MAP sensor At 08:19 AM 9/13/96 -0500, Tom wrote: >Now, I'll just need to find out how much it costs, >what it looks like, how it mounts, etc. Typically, most OEM MAP sensors are little black boxes around 2x3x1", with screw mounting holes built in, a small barbed hose fitting, and a plug or short wiring harness with plug. >The data sheets for these are on the Motorola web page, >(http://motserv.indirect.com/) and they're listed in the Newark catalog >for about $26. The MPX4100 series have all the necessary signal conditioning built in. They are simple 3 wire devices, voltage in (5V) , voltage out (.2v-4.9v), ground. Slap it in a waterproof enclosure and you're done. They may not like high vibration environments, so best to mount them on the firewall, in the passenger compartment and run a hose to the manifold vacuum tree. These may be chaper than new OEM sensors, if you feel like doing the mechanical bit yourself. If you are doing an EFI circuit board, consider mounting the sensor right on your PCB. Vacuum hose doesn't pick up noise, whereas a wiring harness might... One tip on these, the hose barbs provided on the sensor are relatively fragile, one slip when pushing on the hose and it's history. Better to plumb this out to an external metal hose barb on the box, to avoid the chance of breaking off the tit. >Now, which to use -- and what does one do with the data re EFI ?? >Now, the frequency output of the OEM unit -- seems that >that would entail either an F-V convertor and then A-D or an >interrupt driven timer circuit that would return a number of counts >proportional to the period of the sensor output. Any suggestions? Either unit will give you equivalent results, and probably don't require any intervening components to interface to the processor. If you have enough analog channels on your micro, analog is probably easier. If you are short on analogs, and feel confident that you can write the code to measure frequency (piece of cake on an 'HC11, but then so is analog) do it that way. The frequency approach may have better noise immunity than analog. Forget the F-V stuff, it's not necessary or desireable. For dinking around purposes, you may be better off to get a used unit from an auto wreckers, and see if it does what you want. As far as what to do with the data once you've got it, stay tuned... regards dn dnorquay@xxx.com ------------------------------ From: Johnny Date: Sat, 14 Sep 1996 22:55:19 -0700 Subject: Re[2]: Re[2]: O2 Sensor-Leaded gas Good idea. - -j- At [Sat, 14 Sep 1996 11:44:14 -0700 (PDT)] Darrell Norquay wrote: dnorquay> At 01:57 PM 9/12/96 -0400, you wrote: dnorquay> dnorquay> >Come on guys.... that's why I made the archive searchable dnorquay> >through http://efi332. Do a subject search for "lead" and the dnorquay> >whole thread is there! It took several days to put the search dnorquay> >engine and html stuff together.... USE IT! :) dnorquay> > dnorquay> > John S Gwynne dnorquay> > Gwynne.1@xxx.edu dnorquay> dnorquay> Thanx, John. Could you maybe put a reminder about this in the monthly dnorquay> subscriber thingie, just for da halibut? dnorquay> dnorquay> regards dnorquay> dn dnorquay> dnorquay@xxx.com dnorquay> ------------------------------ From: talltom Date: Sat, 14 Sep 1996 23:59:36 -0700 (PDT) Subject: Re: steam! Allright! Anybody got any good ideas about how to reclaim the water when it's been thru the engine?(Water isn't as plentyful as it used to be) Short of making a deal with wppss(Another conceptually and financially bankrupt govt. - washington public power supply system.) on a unused cooling tower that is.? It's not that my old truck won't tow it, it's that at 496' in height I don't think I could license the trailer, never mind clearance problems.:-) I heard of a guy locally that put a outboard motor in a ups like truck with a homemade rotary valve and "modern" boiler(this was in the mid 70's) There were several little problems, but one of them was to much power. He hooked the crank direct to the driveline, no tranny. You had to be careful with the throttle because it had a tendency to fry the 4 rear tires. Imagine grandma able to only drive like a scalded ape because of power. At least that's the way I heard it, and the guy I heard it from knew the one who did it and has never been caught lying in the 30 years I've known him. Another problem is that in Ameirca cars are supposed to be babby buggies in that any idiot is supposed to be able to get in one and reguardless oh how stupid he or someone else is no one's supposed to get hurt.(I didn't do it, don't blame me) Superheated steam(1200psi) in the case of a ruptured pipe can be invisible, and if you happen to walk by can cut your leg off without warning so they tell me at the local steam generating plant. Anyhow suffice it to say that 1200psi anything in a vehicle is going to have a real rough time with the market, and govt.'s. ------------------------------ End of DIY_EFI Digest V1 #274 ***************************** 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".