DIY_EFI Digest Wednesday, 13 November 1996 Volume 01 : Number 344 In this issue: RE: O2 Sensor Open/Close Loop Re: O2 Sensor Open/Close Loop Campfire story re: drivers and sensors OBDII Specs? re: Intel 8061 :: EEC-IV ECM code in oem applications Re: O2 Sensor Open/Close Loop Re: O2 Sensor Open/Close Loop Injector Inductance Re: OBDII Specs? Re: O2 Sensor Open/Close Loop Re: It Howls with small throttle bodies Source for Webber style FI manifolds? Electrohydraulic Camless Valves Re: It Howls with small throttle bodies Re: Source for Webber style FI manifolds? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: cloud@xxx.edu (tom cloud) Date: Tue, 12 Nov 1996 07:17:52 -0600 Subject: RE: O2 Sensor Open/Close Loop > >-> That stuff is an encoded message by the Windows95 mailer. >-> It can be un-encoded by Pegasus mail or any other mailing program >-> which supports uudecode. > > I'm sure all the Windows 95 mailer and Pegasus people are thrilled to >death with their Captain Marvel uuencoder tools. Perhaps they can >amuse each other over in alt.binaries.misc or something. > I just hope it wasn't notification I'd won the lottery! Tom Cloud ------------------------------ From: kleenair@xxx.com Date: Tue, 12 Nov 1996 08:04:53 -0800 Subject: Re: O2 Sensor Open/Close Loop RABBITT_Andrew@xxx.au wrote: > > > The target A/F ratio during WOT can varry from engine to engine. > > this is true, but not in the way you suggest below, > > >More specifically, it is related to fuel pressure, fuel injector > >nozzle design, and injector location. > > this is not true. inasmuch as the effects of these variables are quite > small to the point of being negligible. > > >The objective is to deliver the correct amount of fuel in fine > >particles to the combustion chamber. So theoredically, if all the > >fuel was vaporized, you would not need a WOT enrichment. > > this is also not true. I get the idea you've confused WOT A/F with > acceleration enrichment. WOT is usually richer than stoich because > this produces best power for thermodynamic reasons. Acceleration > enrichment (which also happens at part load) is to maintain the > setpoint A/F by compensating for manifold wetting effects due to > changing manifold pressures. > > >Therefore, on multi port fuel injection systems with higher > >pressures, the WOT A/F is very close to stoichiometric. In fact, > >some newer vehicles (1996) do not go to open loop during WOT! > > given the above, I find this (very) hard to believe, however if you > can quote sources, I'd be interested. > > Andrew Rabbitt > Orbital Engine Company > Perth, Australia. As I understand it, the purpose of the acceleration enrichment (assuming there are no inherent design flaws in the control system that would cause a delay in delivery of fuel) is to deliver an extra burst of fuel during a transient to account for the lag in fuel delivery due to wall wetting. You are correct about the thermodynamic effect of rich A/F ratio during WOT which is very different than transient response as you indicated. The added fuel cools the charge as it vaporizes. Most of my experience is with gasous fuels which cannot benefit from this. Regarding what OEMs do on late model vehicles, I had a 1996 3.8L Buick on the dyno, which maintained its closed loop operation at WOT. However, their motive may have nothing to do with peak power. That may just be a way of protecting the catalyst by reducing excess fuel in the exhaust during extended high engine load periods. Also, just because the system stays in closed loop does not necessarily mean actual A/F is 14.7:1. If the system is flexible enough, you can make the Rich to Lean transient slower than Lean to Rich transient, in effect raising the average O2 sensor voltage. Most systems can also use a different target O2 voltage based on MAP and RPM. ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Tue, 12 Nov 1996 07:50:02 -0600 Subject: Campfire story I was just reading some old posts afore I chunked 'em and came across this reply I sent to the Big_Bronco list. Thought it'd make a nice interlude -- and it is related to efi (moral: turn off your danged fuel pump automatically if engine stops) .... >QUESTION: I have to mount an electric fuel pump, I was >going to do it right by the gas tank, but I don't want to run >a ton of wire for a hot lead to the front of the truck, any >ignition powersources available in the rear end anywhere? Run a 10 or 12 AWG wire from a relay under the hood. Suggest making a bracket -- I made one that fits over the big orange juice can next to the battery on my '82 Bronco and mounted a fuse block and relays on it. I don't know what your plans or what you're doing, but you want the electric pump to turn off when the engine dies: **** Two years ago, a friend and I helped a man and his two young sons pull a Jeep Wagoneer off the edge of a precipice in the mountains of Colorado (seems like it was Imogene pass). He had a switch in the cab for the pump and had not turned it off. He had a carb, and fuel had been trickling down into the engine. When he tried to start it, it locked, so he took out the plugs and got back in to start it. Now, this was many miles from civilization, and he was from Utah. Quite a crowd had gathered (that's mebbe six people in the mountains), including a sheriff's deppity. He got back in to crank the thing. Just as he did, I shouted _STOP_. Too late. I heard the "snap" of the loose spark plug wires as the gas squirted out of the cylinders all over his engine. Every body ran for their fire extinguishers. He did drive it away -- some of the wiring was toast. His carb was full of white extinguisher powder and his engine was covered with it. My friend's parting encouraging word was "don't buy any lottery tickets today". (Course, anyone who takes a Wagoneer up there has already entered some kind of lottery.) ** Thanks, you gave me an excuse to tell a camp fire story. But, do fix your fuel pump where it _automatically_ shuts off if the engine quits. Use the oil pressure switch and AND it with the ignition START switch, or something (can use tach pulses and a one-shot of a couple of seconds -- no spark, no pump). ===== end of campfire story ===== Tom Cloud ------------------------------ From: SRavet@xxx.com Date: Tue, 12 Nov 96 10:04:54 CST Subject: re: drivers and sensors "S. Lastuka" Wrote: | | I am a student at the University of Washington and I am on a team | designing a fuel injection system for a Formula SAE car. We are currently | programming a 68hc11 and are looking into buying the other components that | will be needed for our system. We are trying to find a place that sells | injector drivers (peak and hold). We have heard that Cherry Electronics | sells these drivers but we are having some trouble getting a phone number | for Cherry. If anyone knows of a place that sells drivers we would | appreciate some information ie phone number, price, address. Thank you, | | Sean Lastuka | | Here's the info from the EFI reference list that I maintain. I've been trying to post it and the efi-332 parts list (to the other list...) but they don't go through. Maybe one of the list-admin types can give me a hand here... - ----------------------------------------------------------------------- Parts -- Injectors and Injector Drivers - ----------------------------------------------------------------------- CS-452 and CS-453 -- Cherry Peak and hold fuel injector driver. 4 amp or 2.5 amp peak, then 4:1 reduction in current. Available from Electromotive. HGTP14N40F3VL -- Harris IGBT Coil/Injector Driver. HGTP14N36G3VL - Same at 14N40... but 360 Volt rating, and added resistor from the gate to the emitter, may be the same for all intents... HGTP20N35G3VL - 20 Amp rated, 350 volt clamp, same as above, different ratings. L584 -- SGS-Thomson? You can build a complete driver circuit with one L584 (DIP16), two darlingtons and a few resistors and capacitors. The L584 can be set up to use one of four diffrent load current waveshapes, including peak-hold-drop and peak-drop. L9335 -- SGS-Thompson SGS Thomson sells the L9335 and L9336 Injector Drivers. The former is a 2.4 amp / 0.6 amp peak/hold, and the latter is a 4 amp / 1 amp peak/hold. The pinout looks the same as the Motorola MC3484S2-2 and MC3484S4-2. Cherry Semiconductor also sells the part (CS-452 and CS-453). The L584 is still in production from SGS - they are not easy to get hold of though, I typically get quoted 25-40 week lead times. This is a very flexible chip though and because it works in switch mode the darlingtons don't dissipate much heat (about 1/4 that of LM1949 design). It will produce some RFI because the inductor (injector) is switched fairly fast and is on the end of a long piece of wire (aerial). This solution allows any peak/hold ratio to be implemented. The chip costs about 2.50 (pounds Sterling) in 25 off. LM1949 -Nat'l Semi Injector Drive Controller. Beware - this chip does not operate as a switch mode controller and so the darlington dissipates a lot of heat! It does allow for a low part count solution but fixes the ratio of peak to hold current to 4. MC3484-S4 -- Motorola (discontinued) This part is the same as the Cherry CS-452 and CS-453 MC33293 -- Motorola Note that the 33293 is NOT peak and hold. It's a quad driver intended for high impedence injectors. HIP0081 -- Harris This chip is functionally equivalent to the MC33293, ie. quad current limiting driver with serial diagnostics interface. MGP20N40CL -- Motorola The Motorola MGP20N40CL is a nice IGBT for ignition coil drive. It has internal clamping diodes for voltage protection (400V) and can handle 20 amps. In practice, with peak coil currents of 10A, it only needs a small heat sink. You can drive it directly from a 5V CMOS output. 15 lb/hr injectors high impedance 87 to 92 Ford LTD, Mercury Grand Marquis and Lincoln Town car have 14 ohm 15 pound injectors. 15 lb/hr injectors low impedance I don't know the year, but the Ford Escort with a 1.6l engine has the 2.4 ohm 15 pound injectors. 19 lb/hr Mustang 5.0l 22 lb/hr Chevy 305 tpi 24 lb/hr GM 350 tpi 35 lb/hr Mustang SVO turbo. Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: Thor Johnson Date: Tue, 12 Nov 1996 16:39:27 -0500 (EST) Subject: OBDII Specs? Is there a nettable place that lists the obd-II specs? Wondering how hard it would be to add the logging/whatever OBDII might provide... Thor Johnson johnsont@xxx.edu http://falcon.mercer.peachnet.edu/~johnsont Have you seen the WarpMap lately? http://falcon.mercer.peachnet.edu/~johnsont/warpmap ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Tue, 12 Nov 1996 16:03:50 -0600 Subject: re: Intel 8061 :: EEC-IV Travis, I removed your name from the EEC-IV list as your address was hanging my mail transmission -- are you still there? = = = = = = = = = = = = TO EEC-IV LIST = = = = = = = = = = = = "Keven D. Coates" wrote: >Tom, > >I am very interested in being on this list. I may be able to add some good >information. I have a BS in EET (electrical engineering technology, like EE) >and I have been studying fuel injection for years. I am an Aggie, but I won't >hold your school against you ;-) > >I also work at Texas Instruments, and we are one supplier for the memory for >the next generation Ford engine controller, PTEC. I used to work in the >division that made it. > >I am interested in building my own fuel injection someday, if I ever get the >time. It would be based on a Texas Instruments Digital Signal Processor EVM >board, which is very fast, and cheap ($99). Unfortunately, the interface >electronics would be the major cost and time taker. > >Anyway, please add me to your list of interested EEC-IV people. Thanks. > >Best Regards, >Keven Coates >DSP modem group >Texas Instruments Kevin, Consider yourself added -- someone was going to set up a list, but looks like there may not be enough people interested to sustain it. The EEC-IV modification thread seems to wax and wane (mostly wane) a lot. Clearly, I'm looking for someone else to do all the work and tell me what they found out (if I had the time, I certainly have the equipment to do it). My attitude is the EEC-IV has all the hardware, now all we have to do is the software (growing on what is already there) -- and maybe some additional hardware. Someone want to donate an EEC-IV to me to set up on my bench? I know there's some out there who have -- wanna share what you found with the rest of us? Most important thing is the op-codes for the processor ?? Tom Cloud ------------------------------ From: Daniel Burk Date: Tue, 12 Nov 1996 20:15:04 -0800 Subject: ECM code in oem applications Just a bit of trivia: I got a dump of my '84 ECM for use on my E4ME carb and it was 84 pages. I was told today that the '97 GM 4 cylinder application PCM has over 2200 pages of code. THAT's the march of technology in action if I ever saw it! --Dan ------------------------------ From: "Scot A. Sealander" Date: Tue, 12 Nov 1996 19:54:22 -0800 Subject: Re: O2 Sensor Open/Close Loop kleenair@xxx.com wrote: [Big snip] > Regarding what OEMs > do on late model vehicles, I had a 1996 3.8L Buick on the dyno, which > maintained its closed loop operation at WOT. How do you know that it maintained closed loop? Scan tool? Don't believe it! In the GM code I have seen, they leave the closed loop flag on, even when it is in PE.... and that is most definitely not closed loop. > However, their motive may > have nothing to do with peak power. That may just be a way of protecting > the catalyst by reducing excess fuel in the exhaust during extended high > engine load periods. Maybe, but I personally doubt it. > Also, just because the system stays in closed loop does not necessarily > mean actual A/F is 14.7:1. Well, in the normal GM scheme of things, that is untrue. I have the feeling that open/closed loop operation is not well understood.... though I have not looked at any newer code. My experience stops at about the 1993 model year or so..... > If the system is flexible enough, you can > make the Rich to Lean transient slower than Lean to Rich transient, in > effect raising the average O2 sensor voltage. Is this in reference to the normal dithering of the O2 volts in closed loop? Making the controller asymetrical? Some GM systems are that flexible. The Buicks I have seen are not so flexible. > Most systems can also use > a different target O2 voltage based on MAP and RPM. Now I was under the impression this was because of the O2 sensor temperature (and the temp effect on O2 sensor volts), not because of a different desired AFR.... The sensor is not very useful very far from stoich, so I don't think trying to stay in closed loop would buy you anything. I have been meaning to make a decent scan tool to watch the O2 controller at work in the ECM under actual driving conditions. I have completely worked out GM ALDL protocol, but am not really a programmer. :-( This makes it hard to build a scan tool. Scot Sealander Sealand@xxx.com ------------------------------ From: Mazda Ebrahimi Date: Tue, 12 Nov 1996 21:28:23 -0500 Subject: Re: O2 Sensor Open/Close Loop Scot A. Sealander wrote: > > kleenair@xxx.com wrote: > > [Big snip] > > > Regarding what OEMs > > do on late model vehicles, I had a 1996 3.8L Buick on the dyno, which > > maintained its closed loop operation at WOT. > > How do you know that it maintained closed loop? Scan tool? Don't believe > it! In the GM code I have seen, they leave the closed loop flag on, even > when it is in PE.... and that is most definitely not closed loop. > > > However, their motive may > > have nothing to do with peak power. That may just be a way of protecting > > the catalyst by reducing excess fuel in the exhaust during extended high > > engine load periods. > Maybe, but I personally doubt it. > > > Also, just because the system stays in closed loop does not necessarily > > mean actual A/F is 14.7:1. > > Well, in the normal GM scheme of things, that is untrue. I have the > feeling that open/closed loop operation is not well understood.... > though I have not looked at any newer code. My experience stops at about > the 1993 model year or so..... > > > If the system is flexible enough, you can > > make the Rich to Lean transient slower than Lean to Rich transient, in > > effect raising the average O2 sensor voltage. > > Is this in reference to the normal dithering of the O2 volts in closed > loop? Making the controller asymetrical? Some GM systems are that > flexible. The Buicks I have seen are not so flexible. > > > Most systems can also use > > a different target O2 voltage based on MAP and RPM. > > Now I was under the impression this was because of the O2 sensor > temperature (and the temp effect on O2 sensor volts), not because of a > different desired AFR.... The sensor is not very useful very far from > stoich, so I don't think trying to stay in closed loop would buy you > anything. > > > I have been meaning to make a decent scan tool to watch the O2 controller > at work in the ECM under actual driving conditions. I have completely > worked out GM ALDL protocol, but am not really a programmer. :-( This > makes it hard to build a scan tool. > > Scot Sealander Sealand@xxx.com The reference to varrying the target O2 sensor voltage and biasing its rich / lean swings was not on any particular system. I have used two different aftermarket systems, one designed for gasoline, the other for an alternative fuel. Both the target voltage and the biased swings have a significant impact on A/F ratio, especially with regard to emissions. Regarding the Open / Closed loop on the 3.8 L Buick, I was using Tech-II to monitor the mode of operation AND O2 volts. ------------------------------ From: Stuart Baly Date: Wed, 13 Nov 96 14:49:19 EST Subject: Injector Inductance What is the maximum injector inductance I am likely to find? I'm asking this so that I can size a zener clamp on my output driver circuit accordingly. ========================================================= Stuart Baly (S.Baly@xxx.au) '71 Datrat 1600, '89 Kawasaki GPz900R, '81 Yamaha RD350LC ========================================================= ------------------------------ From: Todd Knighton Date: Tue, 12 Nov 1996 21:20:14 -0800 Subject: Re: OBDII Specs? Thor Johnson wrote: > > Is there a nettable place that lists the obd-II specs? Wondering how > hard it would be to add the logging/whatever OBDII might provide... Thor, I had found it a while back and don't have the address, but just did a search in Metacrawler or something like that for OBD, EPA, and the such. I think I found it in the EPA stuff, kind of tough to sort through though. All the original papers are there as well as some pretty up to date updates. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Tue, 12 Nov 1996 21:22:40 -0800 Subject: Re: O2 Sensor Open/Close Loop RABBITT_Andrew@xxx.au wrote: > > >Therefore, on multi port fuel injection systems with higher > >pressures, the WOT A/F is very close to stoichiometric. In fact, > >some newer vehicles (1996) do not go to open loop during WOT! > > given the above, I find this (very) hard to believe, however if you > can quote sources, I'd be interested. > Andrew, I had read an article a while back in reference to Mercedes maintaining closed loop operation all the way to full throttle on some fo the newer OBDII stuff. They lost a little bit of power but were able to achieve some kind of "Green" standard. Sounds kind of scary to me dealing with an air cooled world. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Tue, 12 Nov 1996 21:31:57 -0800 Subject: Re: It Howls with small throttle bodies tom cloud wrote: > Now I'm confused.... With my limited knowledge and cranial ability, > I thought that throttle size had little effect on FI. I can see that > a larger TB gives less velocity and therefore less momentum and > mixture of the fuel/air, but can anyone 'splain to this ole boy > how to determine a TB size (talking normally aspirated). Tom, There was a really good article just recently in a motorcycle magazine that was specifically about this. They were talking to Mr X from Cosworth about port sizing and manifolds, and according to them, the port sizing was all about a specific port velocity to be obtained at a specific rpm. Though we calc'd some of the numbers backwards to a street oem 911 Carrera engine, and his velocities dictate that Porsche's ports are about 30% too large. Maybe their independent runner, short stacked, 14,000 rpm v8's work differently from 7,000 rpm plenum chambered flat six's. About the most interesting thing in the whole article was in reference to stacks. They proved that an intake runner with any more than about .5 degrees taper, yup that's a 1/2, significantly decreased the flow. I guess that doesn't say much for carbs, jeez they go big, then small, then up and around, then small, then big again. Be careful about your throttle body sizes when referencing them, because it makes a huge difference if you have a single throttle per cylinder, or two cylinders per throttle, or even 8 cylinders feeding a plenum with 4 throttle plates, they're very different worlds. Todd Knighton Protomotive Engineering ------------------------------ From: Jeremy Pronk Date: Wed, 13 Nov 1996 17:18:06 +1100 (EST) Subject: Source for Webber style FI manifolds? Hello, Sorry if this is a little off topic, but I am after a source for the webber style (port type) inject manifolds. What I am actually after is 2 idf webber style fi manifolds ~38mm is size (to replace the stock webber carbies). If anyone on the list sells, or is close to someone who sells the parts, I would love to know! regards, Jeremy, Sydney AUSTRALIA http://www.st.nepean.uws.edu.au/~jpronk/ '83 AlfaSud Ti (Haltech E6 efi) ------------------------------ From: jac@xxx.us Date: Tue, 12 Nov 96 23:53:48 PST Subject: Electrohydraulic Camless Valves There was a thread a few months ago about electrically controlled valves. The November 7 issue of MACHINE DESIGN magazine has an article about Ford's efforts in that direction. The article claims they can operate 16 valves with 125 watts plus some hydraulic power.. The concept is elegant. My complements to the designers. With a small electric blower on the intake manifold they should be able to do away with the electric starter, No cam shaft or gearing is needed. The battery size can be reduced. Everyone should find a copy of this article. I bet we will see more of this in the future. john carroll - ------------------------------------- jac@xxx.us 11/13/96 00:11:33 ------------------------------ From: Doug Robson Date: Wed, 13 Nov 1996 18:35:11 +1100 Subject: Re: It Howls with small throttle bodies Todd Knighton wrote: > > tom cloud wrote: > > > Now I'm confused.... With my limited knowledge and cranial ability, > > I thought that throttle size had little effect on FI. I can see that > > a larger TB gives less velocity and therefore less momentum and > > mixture of the fuel/air, but can anyone 'splain to this ole boy > > how to determine a TB size (talking normally aspirated). > > Tom, > There was a really good article just recently in a motorcycle magazine > that was specifically about this. They were talking to Mr X from > Cosworth about port sizing and manifolds, and according to them, the > port sizing was all about a specific port velocity to be obtained at a > specific rpm. Though we calc'd some of the numbers backwards to a > street oem 911 Carrera engine, and his velocities dictate that Porsche's > ports are about 30% too large. Maybe their independent runner, short > stacked, 14,000 rpm v8's work differently from 7,000 rpm plenum > chambered flat six's. > About the most interesting thing in the whole article was in reference > to stacks. They proved that an intake runner with any more than about > .5 degrees taper, yup that's a 1/2, significantly decreased the flow. I > guess that doesn't say much for carbs, jeez they go big, then small, > then up and around, then small, then big again. > Be careful about your throttle body sizes when referencing them, > because it makes a huge difference if you have a single throttle per > cylinder, or two cylinders per throttle, or even 8 cylinders feeding a > plenum with 4 throttle plates, they're very different worlds. > > Todd Knighton > Protomotive Engineering Well interesting you say about taper because when i had the 50mm throttle bodies my inlet port is 41mm, now with 45 this would reduce the taper signifcantly regards - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson (H) mailto:doug@xxx.au | | (W) mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ From: Doug Robson Date: Wed, 13 Nov 1996 18:37:54 +1100 Subject: Re: Source for Webber style FI manifolds? Jeremy Pronk wrote: > > Hello, > > Sorry if this is a little off topic, but I am after a source for the > webber style (port type) inject manifolds. What I am actually after is 2 > idf webber style fi manifolds ~38mm is size (to replace the stock webber > carbies). > > If anyone on the list sells, or is close to someone who sells the parts, I > would love to know! > > regards, > > Jeremy, Sydney AUSTRALIA > http://www.st.nepean.uws.edu.au/~jpronk/ > '83 AlfaSud Ti (Haltech E6 efi) theres a crowd in AutoAction who sell the Aks ones but they are quite expensive 400 ish each plus attachments. To Be Honest the individual setup i had custom made was about a grand and is obviously lighter and less ( uneccarily ) complex give me a how if you want BRS phone number, and for what sort of engine, regards - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson (H) mailto:doug@xxx.au | | (W) mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ End of DIY_EFI Digest V1 #344 ***************************** 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".