DIY_EFI Digest Thursday, 14 March 1996 Volume 01 : Number 076 In this issue: Re: Suzuki Swift GTi Twincam 1.3 (87) Re: Postscript viewer ? Postscript viewer ? Re: EGT for mixture setting Re: EGT for mixture setting? Re: volumetric efficiency Re: EGT for mixture setting Re: Re[2]: EGT for mixture setting Re: Re[2]: EGT for mixture setting EFI332 project Re: Re[2]: EGT for mixture setting Re: EFI332 project Re: M68000 family processors Re: EGT Re: Suzuki Swift GTi Twincam 1.3 (87) Re: Al u-bends Re[4]: EGT for mixture setting What's my project Re: Encoder Re: Encoder TPI and thermostats Re: Re[2]: EGT for mixture setting UEGO sensor Re: Fuel injector optimum location Re: TPI and thermostats See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Jens Knickmeyer Date: Wed, 13 Mar 96 12:51:43 MET Subject: Re: Suzuki Swift GTi Twincam 1.3 (87) wrote: > > The GTI will gain absolutely _nothing_ from a chip change. In australia, > several of the companies in the 'chipping' market have got their fingers > burnt on GTI's by claiming up to 10Kw improvements. The biggest gain found > (by independant testing) was from advancing the ignition timing 2 degrees, > and it only gave couple of Kw above 7000rpm. The GTI engine is probably the > most highly tuned (as standard) car engine you will ever find. > Michael Fawke > fawkacs@xxx.au I do not know for the Australian market, but ASAIK, the US GTi engines have a bit less power than the German engines, so that chip tuning could possibly give you 10kW in addition. Anyway, I agree with Michael: always be careful with chip tuning. There are good (and rather expensive) kits, and there is a LOT of crap available, esp. for supercharged engines. For my car (Polo-G40), there are kits which ruin the engine quite soon, so that I prefer to stay away from them. Just _my_ opinion... Jens ------------------------------ From: Jens Knickmeyer Date: Wed, 13 Mar 96 12:47:35 MET Subject: Re: Postscript viewer ? wrote: > > Can anyone suggest software to view *.ps (postscript) files that are found > on the web site. > > regards, > Mark Boxsell > MRB Design. Mark, try Ghostview, a PD program to view postscript files. It is available for Unix (Linux!) and DOS and runs quite well. If you have a Linux package, then you already have ghostview around or you can post-install it easily. Otherwise, you should find the DOS and Linux versions on nearly any ftp-server. Jens ('92 VW Polo-G40) ------------------------------ From: "P. Buijs QCL" Date: Wed, 13 Mar 96 13:54:56 CET Subject: Postscript viewer ? In-Reply-To: note of 96-03-13 11:49 try http://www.cs.wisc.edu/~ghost/ghostview/index.html cheers, Paul End of Message ------------------------------ From: Frank Parker Date: Wed, 13 Mar 1996 08:05:02 -0500 (EST) Subject: Re: EGT for mixture setting > > Where are Horiba sensors obtainable. We tried a phone no that was > given in Turbo mag, and the number didn't seem to exist. Does anyone > have a phone or fax # or e-mail address? > > Sandy > ====================================================================== > The Horiba UEGO sensor is available from Horiba @ 5900 Hines Drive, Ann Arbor, MI, USA; phone 313-213-6555. They market a "LAMDA CHECKER LD-01" universal wide range O2 sensor that will read from o.7 to 1.5 times 14.7 stio air fuel ratio.The sensor is made by Ceramic Sensor Ltd, NGK may make the electronics that lineariazes the output and gives a 0-5 volt linear output for a data logger. A very nice unit except since they remarket a allready made unit, the pricing is BAD. The sensor alone is $900 and the output is not linear and the whole unit is $ 2500. I sent email to Link in New Zealand, as they were reported as a possible other source, but no response yet. Anyone know other sources for sensor and/or schmatics for linearizing electronics???? ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Wed, 13 Mar 1996 09:03:53 +0500 Subject: Re: EGT for mixture setting? > I love it when the exhaust glows red! > Are Titanium valves geting cheaper? :-) No, believe it or not ordinary valves will can withstand this. We have tried Ti, but they aren't worth the money for street applica- tions. We try them primarily for weight reduction(higher toss speeds, lower 1.5 order couple, reduced nose stresses), not for valve durability. Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Wed, 13 Mar 1996 09:18:38 +0500 Subject: Re: volumetric efficiency > > "We concluded this when we got an volumetric efficiency of 1.1 !" > > What makes you think having a volumetric efficiency of 1.1 makes your > meter incorrect? It is entirely possible to get volumetric efficiencies > greater than one. What engine? What rpm? What was it designed to do? The engine is a SAAB 2.3L standard production engine (fuel injection, no turbo, no EGR). The volumetric efficiencies close to 1.1 was obtained around 4000 rpm. Normally the vol. eff. should be 0.85 (see any engine book) which makes an error of (1.1-.85)/.85=29%. How can vol. eff. be greater than 1? You need to think more about what the engine books are trying to tell you, which is this: conventional carbuereted production engines have a typical max vol eff of ~85%. There are always fliers in any set of data. Today's production engines can easily exceed 90%, especially with fuel injection and tuned intakes. The project I am working on will achieve 103% vol eff at peak torque and 97% vol eff at peak power. This is with full exhaust and inlet sytems in place and will be a production engine. These are stellar numbers for a production engine, but are par for course for my target market. Still, 85% is at the low end of average for the data I've seen on today's engines. Vol eff values greater than one mean than you have achieved natural supercharging with a properly designed intake manifold working with a matched camshaft. This isn't a miracle, just rare. Race engines regularly achieve 100% or greater. Production engines are not far behind. Saab make good engines with high specific outputs. 110% might be high, but they certainly make more than 85%. In any case, books only give guidelines and averages. They are by no means absolute nor up to date with the latest technology. ------------------------------ From: NassJeff Date: Wed, 13 Mar 96 09:34 EST Subject: Re: EGT for mixture setting Try: Horiba Instruments, Inc. 17671 Armstrong Irvine, California 92714 1-800-446-7422 The phone number was good two days ago... - ----------------------------------------------------------------------------- > cylinders. Second, in order to get *any* correlation between mixture and > EGT temp, you'd have to check with a Horiba lambda sensor. And that is > assuming that such a correlation would exist and give you consistant results. Where are Horiba sensors obtainable. We tried a phone no that was given in Turbo mag, and the number didn't seem to exist. Does anyone have a phone or fax # or e-mail address? Sandy ------------------------------ From: "David M Parrish" Date: Wed, 13 Mar 1996 09:43:30 +0000 Subject: Re: Re[2]: EGT for mixture setting > Is it practical to, put the cold junction into a lot of insulation, eg > shove it into a giant block of polystyrene foam , or in a thermos Nothing that extreme is needed. For accuracy, the cold junction has to be in ice, since the voltage output depends on the temperatures of both junctions. But if you don't care about absolute accuracy, you don't have any cold junction compensation at all. That's how aircraft EGT's are done. They just add a fudge factor to the meter markings, assuming the cold end will be at some reasonable cabin temp. If you want your EGT's to be accurate down to freezing, you can use an Analog Devices AD594. It's a thermocouple amp with built in ice point compensation and runs about ten bucks US. - --- David Parrish EGT at sixty-seven degrees? Hmmm. I thought that engine was running awfully quiet... average cabin temp ------------------------------ From: "Kenneth C. King" Date: Wed, 13 Mar 1996 09:45:00 -0600 (CST) Subject: Re: Re[2]: EGT for mixture setting On Wed, 13 Mar 1996, David M Parrish wrote: > > Is it practical to, put the cold junction into a lot of insulation, eg > > shove it into a giant block of polystyrene foam , or in a thermos > Nothing that extreme is needed. For accuracy, the cold junction has to [ munch ] > If you want your EGT's to be accurate down to freezing, you can use > an Analog Devices AD594. It's a thermocouple amp with built in ice > point compensation and runs about ten bucks US. greetings: has it been considered that if you attach the cold side to something in the intake plenum, then the air inlet temp gague could be used to determine the temp of the cold side of the thermo? this would require us to fix the temp in software, altho we could use the hardware to get a ballpark figure & tweak the final number based on how far off 0deg f we actually are... or is this another case of engineering overkill? :) later, kc - -- "ooooh, crumbs!"if the world is nite, shine my life like a lite"live your life with PASSION"hey waiter, there's a transvestite in my soup"hey mister, are you tall?"all alone in the nite"son of a son of a sailor"John DeArmond fanclub #13 "he's dead, jim"he's not dead, he's electroencephalographically challenged" kc ------------------------------ From: ie21142@xxx.mx (Jose Vicente Loyola Matute) Date: Wed, 13 Mar 1996 10:04:07 -0600 Subject: EFI332 project >From: ie21142@xxx.mx (Jose Vicente Loyola Matute) >Subject: EFI332 project > >>To: diy-efi >>From: ie21142@xxx.mx (Jose Vicente Loyola Matute) >>Subject: EFI332 project >> >>Hello there! >> >>Does anybody knows where i can learn more about the efi332 project? >> >>I tried: >> >>>http://www.cim.swin.edu.au/wwwhome/aden/efi332/332_index.html >> >>and I get: >> >>>Error 404 >>> >>>Not found - file doesn't exist or is read protected [even tried multi] >>> >> >>thanks a lot! >> ------------------------------ From: Fred Miranda Date: Wed, 13 Mar 1996 08:21:39 GMT Subject: Re: Re[2]: EGT for mixture setting >> Is it practical to, put the cold junction into a lot of insulation, eg >> shove it into a giant block of polystyrene foam , or in a thermos can someone explain "cold junction" does it have to do with the voltage produced at the junction of the thermocouple wire and your measuring circuitry? how do you interface a thermocouple? a cmos op amp? Fred ------------------------------ From: fridman@xxx.ca (Robert Fridman) Date: Wed, 13 Mar 1996 10:04:26 -0700 Subject: Re: EFI332 project > >>To: diy-efi > >>From: ie21142@xxx.mx (Jose Vicente Loyola Matute) > >>Subject: EFI332 project > >> > >>Hello there! > >> > >>Does anybody knows where i can learn more about the efi332 project? > >> > >>I tried: > >> > >>>http://www.cim.swin.edu.au/wwwhome/aden/efi332/332_index.html > >> > >>and I get: > >> > >>>Error 404 > >>> > >>>Not found - file doesn't exist or is read protected [even tried multi] > >>> > >> > >>thanks a lot! > >> Things must have been rearanged at the 332 homepage. Try this address: http://www.cim.swin.edu.au/~aden/web-docs/efi332/332_index.html RF. - ------------------------------------------------------------------------- 83 R100 DoD 749 Robert Fridman 84 320i fridman@xxx.ca ------------------------------ From: fridman@xxx.ca (Robert Fridman) Date: Wed, 13 Mar 1996 10:27:45 -0700 Subject: Re: M68000 family processors > Hello fellow tinkerers: > > I am a recent graduate of Mechanical engineering from the University of > Alberta, up here in Canada. I was hoping to glean some information > regarding m68k processors as EFI controllers. Specifically, I am looking > for information on sensor interface with the chip. I am not familiar with > specific sensor outputs ie) does an O2 sensor change a resistance value > with changing AFR? or does it produce it's own voltage output? Is the > output a linear relationship? How about knock sensors?, MAF sensors? etc. You came to the right group;) > I understand Motorolla makes a chip, the M68332 which is specifically > configred for EFI uses. Is this true? I am proficient at M68k family > assembly language, but I am not familiar with PAL's, PIA's PIC's and the > like. Perhaps someone could point me in the right direction; FTP sites, > books, web sites, personal experience etc. Any info you could give me > would be greatly appreciated. There is more information onthe M68332 project at the M68332 home page which can be access through the diy_efi www page at: http://www.cpsc.ucalgary.ca/~fridman/diy_efi. BTW, if you need any 68020 chips sets (CPU,MMU,FPU), I have 4 sets for sale. RF. - ------------------------------------------------------------------------- 83 R100 DoD 749 Robert Fridman 84 320i fridman@xxx.ca ------------------------------ From: ducharme@xxx.com Date: Wed, 13 Mar 96 14:06:08 EST Subject: Re: EGT Fred Miranda wrote: > can someone explain "cold junction" > does it have to do with the voltage produced at the junction of > the thermocouple wire and your measuring circuitry? > how do you interface a thermocouple? a cmos op amp? A thermocouple is a junction between two dissimilar metals which produces a voltage dependent on temperature. When you join a Chromel and an Alumel wire (type K thermocouple used for EGT's) you have a junction. You also have two other junctions that are also thermocouples: Chromel Copper - v2 + + /-----------^---------------- + v1 < Meter - \-----------v---------------- - Alumel + v3 - Copper The voltage at the meter is v1 + v2 + v3. In a laboratory environment, you could put junctions 2 and 3 in an ice bath, and read the voltage v1, and by using a thermocouple reference table, look up the temperature. In the real world, most measuring devices either tie junctions 2 and 3 to a thermal mass of known temperature, or in the case of an analog meter, dismiss it entirely. The reference junction temperature (- 32 deg. F) is then added to the measurement. Another method is to use a cold junction compensator, which is a temperature- dependent voltage source. National Semiconductor makes one, although I don't remember the chip number. To measure the voltage, an opamp wired as a differential amp or high impedance single-ended DC amplifier can be used, or special purpose instrumentation amp can also be used. Differential amps are required when the junction is grounded. While laboratory instruments have a high input impedance (100 Meg is typical) as long as the junction is of sufficient cross-sectional area and the overall wire length isn't outrageous, a differential amp with a 200K ohm impedance will give reasonable results. Remember, a thermocouple can deflect an unpowered analog meter movement! Most types of thermocouples are somewhat non-linear, although for EGT, type K is reasonably flat (maximum variation of 10 degrees through the range of 800-1800 F). Cliff Ducharme ------------------------------ From: Brad Martin Date: Wed, 13 Mar 1996 14:33:17 GMT Subject: Re: Suzuki Swift GTi Twincam 1.3 (87) At 12:51 PM 3/13/96 MET, you wrote: > wrote: >> >> The GTI will gain absolutely _nothing_ from a chip change. In australia, >> several of the companies in the 'chipping' market have got their fingers >> burnt on GTI's by claiming up to 10Kw improvements. The biggest gain found >> (by independant testing) was from advancing the ignition timing 2 degrees, >> and it only gave couple of Kw above 7000rpm. The GTI engine is probably the >> most highly tuned (as standard) car engine you will ever find. >> Michael Fawke >> fawkacs@xxx.au > >I do not know for the Australian market, but ASAIK, the US GTi engines >have a bit less power than the German engines, so that chip tuning could >possibly give you 10kW in addition. >Anyway, I agree with Michael: always be careful with chip tuning. There >are good (and rather expensive) kits, and there is a LOT of crap available, >esp. for supercharged engines. For my car (Polo-G40), there are kits which >ruin the engine quite soon, so that I prefer to stay away from them. > >Just _my_ opinion... > >Jens I think we are confusing rice burners with krautwagons here. ------------------------------ From: Gary Dunn Date: Wed, 13 Mar 96 13:10:02 PST Subject: Re: Al u-bends dan, I would seriously like to get more info on the tubing bender you designed for mandrel bending aluminum. Please let me know if plans are available. I have my own mill and lathe. Thanks, Gary ------------------------------ From: wmcgonegal@xxx.ca Date: Wed, 13 Mar 96 17:21:34 EST Subject: Re[4]: EGT for mixture setting This message is intended for those who are interested in thermocouple information. >I have seen this done using a thermos full of iced water. The >trouble is the ice melts. >Is it practical to, put the cold junction into a lot of >insulation, eg shove it into a giant block of polystyrene foam , >or in a thermos bottle(?) >How about placing the cold end of the thermistor in the coolant >stream,..... It won't give extremely accurate results,..... if you are >just looking for peak EGT, this should work. Every connection in the TC (thermocouple) system between dissimilar metals acts as a TC. Cold junction compensation is used to offset the effects of joining your TC to a measuring device (which has different metals in it). Using a cold junction allows you to read the voltage directly and get the temperatures from a TC reference table. 0C (zero Celsius) is usually used as the reference junction temperature, and in TC reference tables the TC voltage at 0C is 0 volts. For junction compensation of a TC you do not need an actual cold junction at 0C. You need to measure the temperature at the point where the TC probe is attached to your conditioning circuit. Both of the TC wires must be at the same temperature at the junction where they join into the conditioning circuit. If you know the temperature of the junction and you have a TC voltage/temperature look up table you can properly correct your TC voltage reading. To correct for the junction, look up what the voltage for your TC type is for the junction temperature. Add this voltage to the voltage reading from the TC leads at the junction. Then look up the final voltage in the TC reference table to get the actual TC temperature. Of course it is easiest to get a computer to do all this looking up and calculating. If your junction is always at the same temperature (like room temperature) you could always use the same offset voltage (depending on what accuracy you want). A circuit which adds in the proper compensation voltage based on the junction temperature can also be used. Using an ice bath and a second TC at 0C properly connected in with the first TC does the voltage addition for you if you prefer not to have a compact, easy to use, and portable system. If you are just looking for temperature peaks, take your two leads coming from your TC and attach a digital voltmeter in the millivolt range. When you get your highest meter reading you have reached your highest temperature. Curves can be substituted for the tables. Tables and curves are available from TC sources such as Omega Engineering. There is a very good description of TC principles in the Omega Engineering temperature catalog. Some suitable semiconductor devices for measuring the junction temperature are: AD590 - Analog Devices part that outputs 1 uA per degree Kelvin (very easy to use, require a resistor and voltage supply to get a voltage proportional to temperature). This device is good to 150C, so it can be used to measure other things as well. LM335 - National Semiconductor part similar to AD590 >If you accept more error, extension grade T-Couple wire is cheaper. Extension grade has similar characteristics to TC grade over a limited temperature range. The error outside this range may be quite large. Will McGonegal Mobile Sources Emissions Division Environment Canada wmcgonegal@xxx.ca ------------------------------ From: "Jim Staff" Date: Wed, 13 Mar 1996 22:34:24 GMT Subject: What's my project Edward Hernandez > What are you building, kart? Powerplant? Tell us and I'm sure someone > can help you figure out a way to qualitatively determine your WOT > volumetric efficiency. I'm thinking you could try to monitor exhaust > gas temperature(EGT) vs rpm, which can be done without a dyno. I'm building it for the Super Mileage Vehicle Competition; High School Level. For many of you in College and associated with the automotive engineers society (can't remember the 3 letter acronym) have done something very similar. The object is to build a vehicle that passes a bunch of regulations, on turn radius, length, with, hieght, weight, drivers wieght, engine horse power, engine type (Only a Briggs and Stratton!) with a very simple object. Get the most miles per gallon. Our vehicle from Eagan High School is one of the best in the state. We use a fiberglass composite body, we have hydralic disk brakes, and a very efficient low drag vehicle design. We only managed to get 139 MPG last year but set the stock class (No engine modifications run record with (around, after all it's been almost a year since then I don't really remember) 390 MPG!!! After that our motorcycle tranny ate it and died so we got docked for the laps we couldn't complete... Ohh well. The overall winner was Grand Rapids HS with 750 MPG. They use a mechanical injection system that was very ancient. Besides that I'm all done with my system except to build it. And to replace a part I can't find in units less than 25! If anyone out there has an extra 2 or 4 74AC11520's or 54AC11520's from Texas Instruments please let me know. Also If anyone is interested in helping our team, or wants more information. (We love donations the school only gives us $400 a year) you can send a letter to : Eagan High School Attn : Mr. Bob Knodt Independent School Distric 196 4185 Braddock Trail Eagan, MN 55123-1575 Mr. Bob Knodt is the instructor of the activity, if your wondering. If anyone here is real good with electronics I'll send them a copy of my schematic if they send a letter. I'd love to get it checked over. Also if anyone here would works at a place that does board etching of some kind and would like to make a gracious donation of etching my board I'd love that. I'd love it even more if someone out there could redo my board with an autorouter as I laid out all this stuff by hand. Time to stop my bleeding heart letter. Thanks for the help. Jim Staff ------------------------------ From: "Jim Staff" Date: Wed, 13 Mar 1996 23:39:10 GMT Subject: Re: Encoder I think I'l go with the optical encoded disk with the HEDS 1000 as the detector. I only need 100 lines on the disk and the disk is 3 inches in diameter. I can make massive marks. Besides that I can print on a 1200 DPI Laser printer and then photographically generate the laminate wheel I need. Or even better I have a friend who is a machinist and I'd have him machine a disk with the right dimensions out of leaded steel with the right type of finish. Also a briggs want's to die below a typical 1500 RPM, without a load. Since we have a tranny with a nuetral we would die if we ever had to stop. Another thing is Briggs and strattons have a MTBF of several thousand hours. Of course you have to change the oil every 100 hours, and we use zinc impregnated synthetic oil to improve life. The life expectancy on the device you brought to my attention would still be useless to me. 10,000,000 ratations at 4000 rpm (Maximum acceleration RPM in this case) isn't that impressive. Also I need to run this bastard more than likely 100 hours just to hammer out the kinks. Life does suck!! **Attn** : If anyone out there has an port injector rated for Å15 lbs/hr and is willing to donate, give, or sell to me drop me a E-mail!!!!! Jim Staff ------------------------------ From: "Jim Staff" Date: Wed, 13 Mar 1996 23:52:04 GMT Subject: Re: Encoder In message <3142D4CA.2715@xxx.net> writes: > >> That's less than 28 hours at 6000 rpm. Are you sure there isn't > >> another 1000 in there? > > > When was the last time you saw a Briggs + Stratton doing 6000 RPM? > > Modified Briggs and Stratton engines used for go-kart racing spin well > over 5000. > > Bill These folowing Mods could get a Briggs & Stratton 3.5HP well into that range. 1:) Turbocharger : I have already designed most the system, but for my application efficiency not power is important. 2:) Replace the crackshaft with a high efficiency crack. (I have one changed the horse power from 3.5 to 3.9!!!) These are cool things smaller with larger counterwieghts. They provide a smother ride too! 3:) Fuel injection. Especially with a turbocharger could get a briggs in the stratosphere as far as RPM goes. 4:) A new piston : You'd melt a standard piston real quick, they're a low grade aluminum, cheap as hell. Replacing it with a Stainless steel piston would make it nearly flame proof. 5:) A new connecting rod. Most are made of aluminum to, and would shear with no problem at that speed and Horse power. 6:) Increased compression ratio. A briggs and startton has a compression ratio of 4.7:1 max at the factory. I like 10:1 or 11:1 much better. 7:) Change Cam profile to a design more conducive to fuel injection. (A lot of these changes I've considered to do with my Super Mileage Vehicle) Walla: A Briggs that runs at Å10HP, and 7-8000 RPM. All from a 3.5HP I'm deranged, it's sick that I know so much about such a shitty old engine! Jim Staff ------------------------------ From: "George M. Dailey" Date: Wed, 13 Mar 1996 18:56:27 -0600 Subject: TPI and thermostats Gentlemen, A while back I inquired about cold thermostat = more power for tuned port FI engines. As a testiment of my typicly bad luck, the original thermostat in the engine was stuck open. Temps were at record lows in MS, so I drove it as is for several days. Fuel economy was 10-11 mpg (city). After changing the thermostat to 180 (instead of 195 per GM) fuel economy did not improve much and, I still had heater temp problems. I changed the thermostat to a high quality 195 F unit and tossed the cheap 180F AUTOZONE unit. It looks like the final MPG figure for the week will be around 14 - 16 mpg, and the heater is putting out like Bessmer Furnace. Question: My TBI engine used a 180 F thermostat and got 12-13 mpg city. Is the difference software or engine thermodynamics? Why did the cold TPI motor fall on it's face? BTW, I could detect a slight increase in power. I can imagine that the electronics may have allowed the A/F ratio to thicken a bit and advanced the timeing as part of the 'warm up code'. The Chilton manual does list incorrect or damaged thermostat as a possible cause of low fuel economy. Hate to ask this one but, since I lost my pride due to a bad love affair years ago, here it goes :-[] Up to a limit, could one expect better economy at ...say...220F (secondary fan turn on point)? I am aware of the lubrication problems and detonation at high temps, what are others? thanks, GMD ------------------------------ From: Grant Beattie Date: Wed, 13 Mar 1996 19:36:20 -0700 (MST) Subject: Re: Re[2]: EGT for mixture setting On Wed, 13 Mar 1996, Bruno! wrote: > Is it practical to, put the cold junction into a lot of insulation, eg > shove it into a giant block of polystyrene foam , or in a thermos > bottle(?) and tuck it under the dash somewhere? in the extremes of heat > and cold it may help to measure the temp of the juction with a thermistor, > to compensate for the possible change in temperature. Don't bother. Analog Devices (AD595) and Linear Tech (LT1025?) make cold junction compensator ccts and amps. The circuit becomes a no-brainer and the output voltage is 10mv/deg C. GB ------------------------------ From: Darrell Norquay Date: Wed, 13 Mar 96 21:06:02 MDT Subject: UEGO sensor > Anyone know other sources for sensor and/or schmatics for linearizing > electronics???? About 4 years ago, we ran across a family of sensors manufactured by GTE Labs. Among the several flavors was an oxygen gas sensor. The model number was MGS-2000, and it measured 0-100% oxygen (equivalent AFR 0-40). The unit looks like a standard automotive O2 sensor, but with 6 leads. The sensor was developed in conjunction with Waukesha for their stationary engines, what they called the Waukesha Lean Burn Control System. It operates on an electrochemical pumping principle, using zirconia ceramics. It's output is a linear function of oxygen concentration. Unlike an automotive sensor, it does not require a reference gas port (air bleed), and you simply calibrate it in air to read 21% O2. I don't know if this was ever made into a commercial product, or how much it costs, but it could be worth looking into. The sensor has a heater (2 leads), a type K thermocouple for measuring internal temperature (2 leads), and the output, which is a current. Not too difficult to interface to, we actually got a sample of one of these to play with, but it was a different style which was optimised for reading methane gas. It didn't suit our application, but I still have it kicking around somewhere. At the time, I wasn't into EFI, so I didn't pursue it further. The address is: GTE Laboratories 40 Sylvan Road Waltham, Ma 02254 617-466-4123 , Contact: Joseph Cote As I said, this was a few years ago, so I don't know if the phone # / contact name is still valid. If anyone looks into this, keep us posted... regards dn - -- - --------------------------------------------------------------------- Darrell A. Norquay Internet: dn@xxx.ca Datalog Technology Inc. Bang: calgary!debug!dlogtech!darrell Calgary, Alberta, Canada Voice: +1 (403) 243-2220 Fax: +1 (403) 243-2872 @ + < __/ "Absolutum Obsoletum" - If it works, it's obsolete -------------------------------------------------------------------- ------------------------------ From: robert dingli Date: Thu, 14 Mar 1996 17:41:04 +1100 (EST) Subject: Re: Fuel injector optimum location Charlie Harris writes, > Placement of the fuel injector always seems to generate a lot of > "discussion". Unfortunately, there isn't always an easy answer, even in > similar conditions. As an example, I'd like to point out the difference in > injector location on two Indy car engines. The Ford-Cosworth variety places > the injector low in the port, just above the inlet valve. This should enable > more precise distribution between cylinders, though at some loss in fuel > evaporation due to the slightly shorter travel. The Mercedes Benz-Ilmor (my > job, BTW) places the injectors high above the trumpets. This gives slightly > more time for fuel vaporization, but gives slightly less control over where > the fuel ends up. Injector location can also affect throttle response. Injectors closer to the inlet valve provide a shorter path for the liquid film and better transient response. An SAE paper detailing Mazda's 1993 (??) LeMans engine (the 26B quad rotor that was mentioned a few weeks back) mentioned the benefits of at least a couple injector positions with respect to power and economy (they were running in a fuel quantity restricted class). I can't find the reference right now, but as Charles mentioned, injectors placed further up the inlet stream result in better vapourisation and mixing. There is also more time for the vapourising fuel to absorb heat from the air - cooling the inlet charge. The down side is an increase in response time. One of my project cars (Toyota Celica RA23, 3SG 16v) has the injectors mounted in the head which makes inlet manifold fabrication rather easy. regards, Robert - -- Robert Dingli r.dingli@xxx.au Power and Control Systems (+613) 9344 7966 Thermodynamics Research Labs (+613) 9344 7712 University of Melbourne, AUSTRALIA ** he who dies with the most toys, wins ** ------------------------------ From: dzorde@xxx.au Date: Thu, 14 Mar 96 15:06:43 Subject: Re: TPI and thermostats A cold motor means the ECU is runnig open loop and rich, this could explain the bad fuel economy and why the power is not what it should be. The ECU does not (as far as I'm aware) go into closed loop until everything is reasonably warm. Dan dzorde@xxx.au ______________________________ Reply Separator _________________________________ Subject: TPI and thermostats Author: diy_efi@xxx.edu at INTERNET Date: 3/14/96 2:37 PM Gentlemen, All gone thanks, GMD ------------------------------ End of DIY_EFI Digest V1 #76 **************************** 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".