DIY_EFI Digest Sunday, 24 August 1997 Volume 02 : Number 286 In this issue: Re: For REALLY good injection, check this out Re: For REALLY good injection, check this out Re: For REALLY good injection, check this out Re: For REALLY good injection, check this out Re: BOSCH stuff Re: BOSCH stuff Re: For REALLY good injection, check this out No Mo O2 sensor Re: No Mo O2 sensor Re: No Mo O2 sensor Re: No Mo O2 sensor Re: Injector control question See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Corey L. Cole" Date: Sat, 23 Aug 1997 10:16:20 -0700 Subject: Re: For REALLY good injection, check this out Terry Martin wrote: > I'd better mention really good injectors here or I'll be hissed at. :-) > I still think compressing part of the air charge into the injector > stream is an idea with merit. It would act the same as anything else > when decompressed (injected), and cool the combustion chamber. If it was > done just at the overlap point of exhaust and intake, the cylinder would > not heat the intake charge as much by virtue of residual heat from the > power stroke (exhaust), and would increase the volumetric efficiency of > the engine. It would also serve to better atomize the injector stream. > No? > > Terry How about combining EGR with the compressed air? You wouldn't get the benefit of cooling quite so much, but at most settings you could use "free" exhaust gas and keep the load off of whatever compressor is adding air. Then, as throttle increases, you add less and less EGR into the injector. I can see some problems with hot gases and combustible fluids, but who knows, there might be some way around it... As far as adding straight air, sounds good. You could go direct injection and get real small droplets for complete combustion. Hmmm, I think I can drill a 9/16 hole right here in my cylinder head :) - -- ============================================================================== Corey L. Cole | I was standing on the side of the road, M/S 19-HH | rain falling on my shoe. E-mail: corey.l.cole@xxx.com | I was heading for the east coast, Phone: 206-662-3596 | Lord knows I've paid some dues. | Tangled up in blue. ============================================================================== Disclaimer: If I'm not speaking FORTRAN, I'm not speaking for Boeing. ------------------------------ From: "Christopher G. Moog" Date: Sat, 23 Aug 1997 14:43:54 -0400 Subject: Re: For REALLY good injection, check this out > Terry Martin wrote: > > I'd better mention really good injectors here or I'll be hissed at. > :-) > > I still think compressing part of the air charge into the injector > > stream is an idea with merit. It would act the same as anything else > > > when decompressed (injected), and cool the combustion chamber. If it > was > > done just at the overlap point of exhaust and intake, the cylinder > would > > not heat the intake charge as much by virtue of residual heat from > the > > power stroke (exhaust), and would increase the volumetric efficiency > of > > the engine. It would also serve to better atomize the injector > stream. > > No? > > > > Terry > Orbital engine from Australia has been experimenting with this for several years for 2-stroke engines. As I understand it the proper amount of fuel is blown into the combustion chamber with ~100 psi air. A small belt driven compressor supplies the air. The idea is to get good atomization and allow injection after the exhaust port has been covered (preventing raw fuel from going out the exhaust). They have licensed the technology to GM, Ford, Toyota and others. So far nothing meeting NOx has been a problem so no marketable engine has come out. ------------------------------ From: Terry Martin Date: Sat, 23 Aug 1997 12:44:41 -0700 Subject: Re: For REALLY good injection, check this out Corey L. Cole wrote: > > Terry Martin wrote: > > I'd better mention really good injectors here or I'll be hissed at. :-) > > I still think compressing part of the air charge into the injector > > stream is an idea with merit.... It would also serve to better atomize the injector stream. > > No? > > > > Terry > > How about combining EGR with the compressed air?... As far as adding straight air, sounds good. You could go direct injection and get real small droplets for complete combustion. Hmmm, I think I can drill > a 9/16 hole right here in my cylinder head :) I have a hole-saw, if your drill won't accomodate the 9/16 :-0 You could dump just about anything into the injector stream,(except maybe lumps of coal). That's the beauty of injectors. They do for heat engines what transistors did for electrical apparatus. It takes an analog equivalent (carb), and replaces it with digital, (injectors form discrete packets). All of the fuel charge, (and exhaust), can be precisely measured and metered, without bothersome interference like ambient heat, pressure, gas composition, etc,etc. Detectors can precisely measure every variable, and instantly adjust accordingly. One element that nobody seems to pay much attention to is the fact that roughly 80% of the air component is nitrogen, and does absolutely bupkiss, except pollute the crap out of everything. Being a diver, I'm acutely aware of nitrogen saturation of tissue under pressure, and the effect that compression has on the partial pressures of the various gasses. I suppose the so called "oxygenation" of fuel has some merit, but it's still a concept trying to formulate fuel to fit both carbed, and injected engines. That's just plain stupid. If the gas companies want to get on the boat, why not formulate a fuel specifically for injected engines, (like diesel is), and make a serious attempt to saturate the fuel with oxygen, so that the intake air stream is reduced. Hell, they could even get into agriculture, and use the oxygen given off by plants as the source by tapping the enriched air of the massive acres of greenhouses popping up everywhere. I have no idea what sort of oxygen absorption a particular liquid hydro-carbon has, (pressure dependant, among other things), but getting even a small amount of the nitrogen out of the process in favour of oxygen has big leverage on combustion and power efficiency, as does recovering lost heat, and moving heat out of the intake charge. Terry ------------------------------ From: Terry Martin Date: Sat, 23 Aug 1997 12:50:45 -0700 Subject: Re: For REALLY good injection, check this out Christopher G. Moog wrote: > Orbital engine from Australia has been experimenting with this for > several years for 2-stroke engines. Hmm, nothing like re-inventing the wheel. :) Terry ------------------------------ From: "Steve Meade" Date: Sat, 23 Aug 1997 13:47:54 -0700 Subject: Re: BOSCH stuff - ---------- > From: Michael McBroom > To: diy_efi@xxx.edu > Subject: Re: BOSCH stuff > Date: Friday, August 22, 1997 5:35 PM > > > It appears that you have uncovered the truth. According to Charles I just *knew* I might be on to something! :) > Probst in his book _Bosch Fuel Injection & Engine Management (Robert > Bentley, 1991), all 944s have Bosch Motronic systems. He makes no > mention of JE-Jetronic, although he mentions a few variants of > K-Jetronic, one of which is KE-Jetronic. Citing from Probst again, > there are three basic Motronic systems (up to 1991, that is): Motronic, > LH-Motronic, and KE-Motronic. Yours should have the plain Motronic > system (and yes, Probst shows your 325 as using the same one), which is > characterized as having such basic features as an air-flow meter, pulsed > injection, idle stabilization, and ignition timing control. > The timing is the big one for me, it means adding a Weltmeister chip does more than changing the fuel maps; it can change timing too. > Incidentally, I can recommend Probst's book. I bought it to learn more > about Bosch efi systems in general and LH-Jet in particular, and it has > helped in that regard. I wish he would have gone into considerably more > detail in several areas, but it has served as a very worthwhile > introduction. > I was just going to ask you how you liked his book but it looks like you've already answered the question for me. I'm a bit curious, I remember your posts a while back about your adaptation of the Saab boost control system and I was wondering, is your 745 faster than your 765? I must thank you for something else entirely; a month ago I went out and bought a new camera. I traded in my old (and very heavy) Minolta XG-1 and lenses and hardly had to pay very much at all for the new camera. I noticed the guy pulled out your book when looking up prices. > -- > Best, > > Michael McBroom > > '87 745T 123k w/APC Visit the Volvo Performance Site: > '88 765T 156k http://mcbrooms.com/volvo > _________________________________________________________________________ > > Graduate Student, Linguistics Author of > Research Interest: Biological Origins =McBroom's Camera Bluebook= > of Language http://mcbrooms.com > California State University, Fullerton > _________________________________________________________________________ ------------------------------ From: "Steve Meade" Date: Sat, 23 Aug 1997 14:22:55 -0700 Subject: Re: BOSCH stuff - ---------- > From: Land Shark > To: diy_efi@xxx.edu > Subject: Re: BOSCH stuff > Date: Friday, August 22, 1997 11:20 PM > > At 12:57 PM 8/22/97 -0700, you wrote: > > > Motronic all 944's in the US are Motronic DME > Well, that's certainly good news since now I know that it has chip-adjustable timing. The factory chip only requires 87 octane so I think there may be some gain in timing advancement. > If you tell me your 0 261 number, I can tell you what version > any (maybe) the processor type/EPROM type > Just went out and it is a 0 261 200 077 box. I had one of your chips in my BMW and was wondering if you were going to get into Porsche chips. :) I say that with half seriousness since I can only find 3 companies making chips for my car: Superchips: I'm worried when they say on their web site, "We can make a chip for any car in a couple of hours." Weltmeister: These chips are actually made by Dinan, and I know yours are better than that. Autothority: Can I really trust a chip from the same company that makes the "Flowtech" noise system? Well, if you find out anything on my box just drop me a line. =-=-=-=-=-=-=-=-=-=-= Steve Meade smeade@xxx.com > Jim C ------------------------------ From: Don Bowen Date: Sat, 23 Aug 1997 16:55:11 -0700 Subject: Re: For REALLY good injection, check this out Seems like it would also do to reduce NOX even further than the current oxygenated stuff. At 12:44 PM 8/23/97 -0700, you wrote: I suppose the so called "oxygenation" of fuel has some merit, >but it's still a concept trying to formulate fuel to fit both carbed, >and injected engines. That's just plain stupid. If the gas companies >want to get on the boat, why not formulate a fuel specifically for >injected engines, (like diesel is), and make a serious attempt to >saturate the fuel with oxygen, so that the intake air stream is reduced. >Hell, they could even get into agriculture, and use the oxygen given off >by plants as the source by tapping the enriched air of the massive acres >of greenhouses popping up everywhere. I have no idea what sort of oxygen >absorption a particular liquid hydro-carbon has, (pressure dependant, >among other things), but getting even a small amount of the nitrogen out >of the process in favour of oxygen has big leverage on combustion and >power efficiency, as does recovering lost heat, and moving heat out of >the intake charge. > >Terry > > > Robert Bowen California, via Thailand, Czech Republic Linguistics Student; mechanic; Vespa collector *1967 Toyota Corona, 1976 Vespa Rally 200* Ska is the ONLY Jamaican music that counts ------------------------------ From: verde@xxx.) Date: Sat, 23 Aug 1997 19:21:41 -0700 (PDT) Subject: No Mo O2 sensor I was talking with a friend about how to get rid of or fooling the ECU into thinking the O2 sensor was reading perfect. He thought that if you supplied the right amount of voltage to the sensor then it would read perfect all the time and never effect the ECU. That way you can use the water temp and other sensors to better tune the EFI. Any thoughts???? Jason G. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> http://rogue.northwest.com/~verde <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ------------------------------ From: senator@xxx.edu (Bill Bradley) Date: Sat, 23 Aug 1997 20:33:12 -0700 (PDT) Subject: Re: No Mo O2 sensor > > I was talking with a friend about how to get rid of or fooling the ECU into > thinking the O2 sensor was reading perfect. He thought that if you supplied > the right amount of voltage to the sensor then it would read perfect all the > time and never effect the ECU. That way you can use the water temp and other > sensors to better tune the EFI. > > Any thoughts???? Don't count on it... Many ECUs check for a voltage swing on the oxgen sensor to make sure it's connected, warmed and functioning properly. If you just give it a straight voltage reading it will most likely go open loop and generate an error code. The temperature sensor is a work around. If you fool the ECU into thinking that the engine is cold, it should allow a richer "cold" mixture (assuming that that's your goal) What type of FI are you trying to play with? Bill ------------------------------ From: Orin Eman Date: Sat, 23 Aug 1997 20:57:39 -0700 (PDT) Subject: Re: No Mo O2 sensor > I was talking with a friend about how to get rid of or fooling the ECU into > thinking the O2 sensor was reading perfect. He thought that if you supplied > the right amount of voltage to the sensor then it would read perfect all the > time and never effect the ECU. That way you can use the water temp and other > sensors to better tune the EFI. > Any thoughts???? The ECU will think the sensor is dead if you do that. It expects the O2 sensor output to cycle from rich to lean as it varies the mixture. If the voltage doesn't change, it probably assumes that the sensor is disconnected or that there is a short somewhere... you may end up with some very poor running limp home mode! Orin. ------------------------------ From: "Steve Meade" Date: Sat, 23 Aug 1997 21:09:09 -0700 Subject: Re: No Mo O2 sensor - ---------- > From: Jason G. > To: DIY_EFI@xxx.edu > Subject: No Mo O2 sensor > Date: Saturday, August 23, 1997 7:21 PM > > I was talking with a friend about how to get rid of or fooling the ECU into > thinking the O2 sensor was reading perfect. He thought that if you supplied > the right amount of voltage to the sensor then it would read perfect all the > time and never effect the ECU. That way you can use the water temp and other > sensors to better tune the EFI. > > Any thoughts???? > I've actually thought about this approach to modification. There are several problems, though. With what you describe above, you actually lose a lot of functionality in the ECU. While driving, your engine actually uses the O2 sensor to provide a good mixture. Also, your car already does what you are trying to achieve (no o2 sensor input) while at wide open throttle. Intercepting the water temp sensor is a good idea though. I believe that many GM EFI units actually have a 2d table in them where the mixture is richened to varying degrees according to temperature. You could probably even build a a knob-type device to control mixture on demand. Of course, this would only work at WOT since the O2 sensor would override the rich condition anyways. If you wanted to be really smart and sophisticated you could build micro-based computer which takes in the normal water pump signal and either amplifies or attenuates according to a table in rom with RPM vs fuel. I think this would be a great alternative to trying to reverse engineer an OEM system. However, this system would only work if you had actually done engine modifications which require different fueling (ie: cam, increased displacement, ported head, etc.) Otherwise, you're just richening up the mixture. =-=-=-=-=-=-=-=-=-=-= Steve Meade smeade@xxx.com > Jason G. > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > http://rogue.northwest.com/~verde > <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ------------------------------ From: Seth Date: Sat, 23 Aug 1997 22:41:38 -0700 (PDT) Subject: Re: Injector control question On Fri, 22 Aug 1997, Tom Cloud wrote: > I wrote: > > >> In examining my Holley ProJection (model 502 analog) I find > >> that the pulse width to the injectors is a constant (approximate) > > [ snip ] > > >> NEXT ... > >> > >> Some time back (few weeks ago) there was a question > >> about building a meter to monitor the PW of injectors > > and Bruce replied: > > >About a year ago, I made such a meter out of a PIC 16C56 chip > > but Bruce, you didn't address my primary query -- that > being: > > "why does one want to know the PW when it's the > duty cycle that's impotent (regardless of whether > one uses fixed PRR/var. PW or fixed PW/var. PRR) ?? > > Am I incorrect about that ?? I recognize that there's going > to be errors in fuel delivery calcs at the opening and closing > of the injector, so short pulses would deliver less fuel/time > than long pulses and this would imply that a simple duty > cycle measurement would have some inherent errors, but I'd > think they'd be minimal. > > IOW, seems that duty cycle is what you want to measure, not PW ???? > > > Tom Cloud > > Ever stop to think .... and forget to start again ?? > Why would you want to know the duty cycle? Other than determining if you break 85% and rick holding the injector open... If you have a sequential port efi, wouldn't you align the injectors in phase with the intake event,, so frequency would vary with rpm, then adjust pulse width according to volumetric efficiency at that point (determined by MAP or throtle position). That is what I am designing around with my 68HC11 project. They duty cycle is all over the map from ~1.5% to ~85%, but the pulse width is from 1.5ms to 18 ms. Maybe I am overlooking something? Seth ------------------------------ End of DIY_EFI Digest V2 #286 ***************************** 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".