DIY_EFI Digest Monday, March 27 2000 Volume 05 : Number 124 In this issue: Re: Valve seats Re: Cheap protection... Re: DIY_EFI Digest V5 #123 Re: Cheap protection... Re: Cheap protection... Measuring weight Re: Cheap protection... Input protection Re: 8051 EFI Re: MAP sensing for IR systems Re: MAP sensing for IR systems Re: MAP sensing for IR systems O2 sensor response times See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sun, 26 Mar 2000 13:05:18 +0100 From: Ade + Lamb Chop Subject: Re: Valve seats At 13:34 25/03/00 +0000, you wrote: >I have a cast iron head, Ford V6 Essex, which does not have valve seat inserts. It >has to date been very reliable, running on a Carb and ECU ignition (home made). >Here in the UK we have just (1st Jan 2000) had leaded fuel banned, so I am >concerned as to the potential problems. I've heard so much conflicting advice about >un-leaded fuel and valve seat inserts. Does anyone have any real experience of >running without lead on a tuned motor? Not personally but this has had a lot of coverage in the Mini comunity. Is supposed to be the least tollerant of UL. I am running a 100bhp mini on UL with hardened valve seats, 10:1 CR and a hot road Cam (kent 286). I am not suffereing any problems due to the lower octane of UL (95ron) Without the hardended valve seats you need LRP but this doesn't protect as well as leaded does so if you have a heavy right foot or do long duration high speed motorway stuff then you need hardened seats. Go along to your local machinist and ask how much it would cost to get hard valve seats fitted you only need the exhaust seats done. I was quoted about 20ukp per seat. If you are running CR too high for 95ron UL then will need to run super UL or LRP as they both have almost the same Ron but LRP is cheaper and a lot more available. 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: Sun, 26 Mar 2000 09:45:26 -0800 (PST) From: Orin Subject: Re: Cheap protection... > At 08:59 AM 26/3/2000 +0000, you wrote: > > Use a voltage divider and do the de-bounce/filtering in software. > > Yeah agree with that for the most part unless the signal range is > limited - then use a cheap transistor like BC547 etc. > ie Atennuate first then amplify to the 5v range required. This is a good idea - a simple transistor inverter. I've used it to monitor the coil drive signal. > > > A simple signal diode from input to Vcc will protect your uP as the Vcc > is low > >imperance. > > > > I can see a problem with this. Although one hopes the 5v rail is low > impedance - remember its connecte to your other logic so its not good > practice to use this as a sink for any incoming noise - it will be > reflected across the voltage to your CPU and eprom etc - it might be > OK for a range of frequencies but, 5v regulators are > notorious for parasitic oscillations, leave the o/p bypass cap off and Another problem is that the logic input probably has a protection diode to Vcc too. Which will conduct first? Then some devices (MC145051 AtoD in particular) don't like their protection diodes being turned on. I agree totally with not shunting to the 5V line. I used a diode to a shunt regulator set to about 4.7V in one design to keep an MC145051 happy in over-voltage conditions. For a simple on/off though, a series resistor and a 4.7V zener diode works for me. Add a capacitor in parallel with the zener for filtering if necessary. What series resistor? Well an OEM ECU I have around uses 10k. Orin. - ---------------------------------------------------------------------------- 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: Sun, 26 Mar 2000 15:17:44 -0800 From: Scotty Grover Subject: Re: DIY_EFI Digest V5 #123 'Scuse me for butting in, but a CD4049 (Inverting) or CD4050 (Non-inverting) may work better than a 74C14. The CD's (Powered by 5V) accept 15V at their inputs. > I don't think the 74C14 Schmitt trigger would like 12V input if it's > running from a 5V supply rail. The Schmitt trigger connects to the > inputs of the uC, which shares the regulated 5V supply. - ---------------------------------------------------------------------------- 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: Mon, 27 Mar 100 09:36:41 +0800 (WST) From: Bernd Felsche Subject: Re: Cheap protection... Scotty Grover writes: >> I don't think the 74C14 Schmitt trigger would like 12V input if it's >> running from a 5V supply rail. The Schmitt trigger connects to the >> inputs of the uC, which shares the regulated 5V supply. >'Scuse me for butting in, but a CD4049 (Inverting) or CD4050 >(Non-inverting) may work better than a 74C14. The CD's (Powered by >5V) accept 15V at their inputs. Thanks. You're excused for butting in. :-) That brings the parts count down nicely; just a series resistor required ahead of the buffer for minimal protection. - -- 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: Mon, 27 Mar 2000 13:38:37 From: "Mike (Perth, Western Australia)" Subject: Re: Cheap protection... At 09:36 AM 27/3/2000 +0800, Bernd Felsche wrote: >Scotty Grover writes: >>'Scuse me for butting in, but a CD4049 (Inverting) or CD4050 >>(Non-inverting) may work better than a 74C14. The CD's (Powered by >>5V) accept 15V at their inputs. >Thanks. > >You're excused for butting in. :-) The only 'slight' problem with that is if the Vcc rail to the device is lower then the input spike (or whatever) then it forward biases the onchip parasitic diode - depending on the type of CMOS you are using it could cause a latchup anywhere on the chip... If however the input resistor values are high enough then the resulting current is lower, less likelihood of latchup. Also best to add a cap from cmos device signal input to ground for these reasons:- a. From c=Vdi/dt there is far less chance of a transient passing a current into the CMOS parasitic diode. b. Provides some minimal debounce, saving some CPU overhead. From t=1.1RC you can obtain quite nice debounce values without s/w overhead. Eg. 1Meg and 1uF gives a time constant of about 1 second c. A nice blue cap breaks up the clour scheme somehwat ;-) >That brings the parts count down nicely; just a series resistor >required ahead of the buffer for minimal protection. Hopefully the one extra cap won't upset the parts count too much, I think a 1uF 35V electro is around 20c or so in small qtys. If you wanted to be real sure you didn't expose the inputs to any big spikes, I'd add a 6v8 transzorb in parallel with cap and a 10K or so resistor from this conenction to the CMOS input. The transzorb's have a nice strong cutoff and act as a short at anything above 6.8v - they are quite commong and cheap in qty... Also IMHO, if you want the most cpu time avalable for nice-eties such as PID and kalman filtering (I'm talking EFI here) then its worth bending the rule about "having s/w do as much as possible". Although a s/w debounce is trivial - if you have a lot of them it can interfere with best task scheduling to some degree. With basic input filtering for discrete inputs provided by resistors and caps the CPU has *full time* to do the interesting stuff for compensations and a consistent 'time' term to scale the PID functions appropriately etc ie. Without time spent on debounce, the time term in a calc is synchronous and less chance of instability... Rgds Mike Massen Ancient Sufi saying: "Should your God save you from adversity, choose another God" Pictures of site installation at Mendulong near Sipitang, Sabah (Malaysia) for container based RAPS... http://www.wantree.com.au/~erazmus Vehicle modifications on GMH Turbo, twin tyres, possible 175Kw at wheels Preliminary pictures at http://www.wantree.com.au/~erazmus/Twin_tyre_vehicle/ My editorial on twin-tyre opinion and good reference about tyres:- http://www.geocities.com/MotorCity/2195/ttyreopinion.html - ---------------------------------------------------------------------------- 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: Mon, 27 Mar 2000 00:06:45 -0600 From: MysticZ Subject: Measuring weight In all of the calculating and figuring for the fuel injection system I came across a little problem. I need an accurate way to measure the bike. I got a rough idea by putting each wheel on a bathroom scale and adding the results (366 pounds wet, roughly 25 pounds less than stock :) However, I'm not happy with that setup since it's only accurate to about 2-3 pounds (assuming the scale's right) and a pain in the ass to set up. Anyone know where I could find some kind of gizmo that converts weight to voltage accurately? I'd like to interface the whole thing to an LCD that displays the individual weight of each wheel, the total weight, and the weight distribution. A stamp or Oopic should do that easy. - -- Steve 97 Chevy Camaro Z28, Mystic teal, A4, not stock 90 Kawasaki EX500A4, black, M6, not even CLOSE to stock! lt1_z28@xxx.net/~lt1_z28 Aluminum, steel, carbon fiber, titanium, and two cast iron balls. McMillan Motorsports- http://www.mmsbikes.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: Sun, 26 Mar 2000 23:04:21 -0800 From: Ludis Langens Subject: Re: Cheap protection... "Mike (Perth, Western Australia)" wrote: > > >>'Scuse me for butting in, but a CD4049 (Inverting) or CD4050 > >>(Non-inverting) may work better than a 74C14. The CD's (Powered by > >>5V) accept 15V at their inputs. > > The only 'slight' problem with that is if the Vcc rail to the device is > lower then the input spike (or whatever) then it forward biases the onchip > parasitic diode - depending on the type of CMOS you are using it could > cause a latchup anywhere on the chip... Check the 4049 and 4050 specs again - they are designed to handle input voltages much higher than the supply rail. These two chips are made without a diode between the input and the VCC pin. > If however the input resistor values are high enough then the resulting > current is lower, less likelihood of latchup. Also best to add a cap from > cmos device signal input to ground for these reasons:- GM uses the 4049 in their older ECMs to buffer "switch" type inputs. They also use a 100K series resistor, a signal diode to VCC, and a small filter capacitor (perhaps 1000pF). The switch inputs also have a 1200 ohm resistor to either ground or the 12V battery voltage. The 1200 ohm is before the 100K series resistor. Look at: http://www.cruzers.com/~ludis/1227170sheet3.gif - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ - ---------------------------------------------------------------------------- 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 10:13:43 +0200 From: Nic van der Walt Subject: Input protection >Well, seeing that he drew it for my benefit... (I only have a "glass >tty") and I'm used to squinting when ASCII art goes drunken... > >>> >>> --+--- +5v >>> l >>> l >>> ------- >>> / \ >>> /___\ 1N4148 >>> l >>> l >>> +---------+ l >>> 12v source >-----l 13k l---+------------> input >>> input +---------+ l to uP >>> l >>> l >>> +-----+ >>> l l >>> l 10k l >>> l l >>> +-----+ >>> l >>> l >>> l >>> --+----- GND > >Is that better? I have about 30 thousand automotive alarms running around and experience shows the following: Never ever ever dump energy to VCC. Never rely on simple voltage division. The 12V line goes from 7V to 16V worst case. And those 200V spikes someone mentioned does get into everything... ;-( The best solotion is: IN---10K---------------10K---OUT | | | --- 10K 10nF / \ | | --- | | | | | GND GND GND The diode is a 4.7V zener. You could get away without the cap up to a point. This circuit works as well as the best ESD protection circuit money can buy (Harris SP720) with the advantage that is needs no connection to VCC at all. Make sure your supply is well protected. Minimum is a load dump tolerant regulator like the LM2931 with a tranzorb and a reverse polarity diode protecting it. Regards N. - ---------------------------------------------------------------------------- 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: Mon, 27 Mar 2000 01:16:16 PST From: "mike mager" Subject: Re: 8051 EFI Paul Corner mentioned a home built EFI project: (complete quotation below) >I've been playing around with . . . . . . ending up with a 12MHz 8051 based design. What state of play are others at ? Hi, Paul, I have an application in mind for a custom ECU, myself. I'm curious just _which_ '8051' you have chosen. I have a so-far unused Dallas "Speed It uP" (Dallas' own pun) DS80C320, which is, as it sounds, a fancy 8032, but with a high clock speed and reduced clock-cycles per instruction. After a bit of (attempted!) rational thought, I have considered strongly using a Motorola processor (designed for the application), if not the (totally irrational?) Infineon AUDO TC1775 TriCore, which is also aimed at engine management (just plain 'heavy sand' - fun). A "batch of boards", you wrote; is this an idea for production? What's your application? Mike >From: Paul Corner >Reply-To: diy_efi@xxx.org >To: diy_efi@xxx.org >Subject: 8051 EFI >Date: Fri, 24 Mar 2000 20:11:57 +0000 > > >Hi > >I've been playing around with a few ideas for engine management for a >couple of >years or so now. Started out with the SSI 67F687 chip, alas no more, >ending up >with a 12MHz 8051 based design. After getting a batch of boards made, I >hacked >some machine code up and got my engine running after a fashion. Due to >other >commitments, the project was put on hold. Now with the summer months >coming, I >want to get this thing going again. With a couple of issues still left to >resolve, I look foward to a healthy exchange of ideas. > >What state of play are others at ? > >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 > ______________________________________________________ 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: Mon, 27 Mar 2000 01:42:12 PST From: "mike mager" Subject: Re: MAP sensing for IR systems Bruce, Bernd, thanks for the suggestions. I was hoping that there was a way to avoid commoning the MAP source. I did leave out the aspect of the fuel-pressure regulator reference source - very silly of me. Thanks, Mike >From: "nacelp" >Reply-To: diy_efi@xxx.org >To: >Subject: Re: MAP sensing for IR systems >Date: Sat, 25 Mar 2000 15:27:05 -0500 >You need to tie em all together, >that is each runner to a common "tank" of min volume, or redo all the >filtering, in the ecm. But, then, you want them tied together for >referencing to the Fuel Pressure regulator, >Also, helps to a small degree smooth out the idle. 1/16-1/8" ID line. >Grumpy > > What are the practicalities of MAP sensing for an IR (Independent >Runner) intake system? 'Theoretically', with symmetrical intake and >exhaust, each cylinder has the same MAP, and needs the same fueling and >advance, but what happens in the real world? My books fail to address this >obscure issue. ______________________________________________________ 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: Mon, 27 Mar 2000 04:36:12 -0600 From: MysticZ Subject: Re: MAP sensing for IR systems mike mager wrote: > > Bruce, Bernd, > thanks for the suggestions. I was hoping that there was a way to avoid > commoning the MAP source. I did leave out the aspect of the fuel-pressure > regulator reference source - very silly of me. So use individual MAP sensors, but have a 2nd port in each runner for the fuel pressure. Or just hook the FPR to a single runner since it's likely to be close enough to the rest of them for a "low-tech" FPR anyway. The system I'm working on treats each cylinder as it's own engine, but I only have 2 cylinders to deal with and no need for any vacuum/MAP reference of any kind. Not the most precise way of controlling fuel, but it's close enough. With an engine that can see 5000 rpm and 11000 rpm in under a second there's more important things to worry about ;) MAP and MAF just aren't fast enough. Closed loop and loopup tables based on RPM and TPS will handle it if the processor is fast enough. Now to worry about that fuel atomization issue... - -- Steve 97 Chevy Camaro Z28, Mystic teal, A4, not stock 90 Kawasaki EX500A4, black, M6, not even CLOSE to stock! lt1_z28@xxx.net/~lt1_z28 Aluminum, steel, carbon fiber, titanium, and two cast iron balls. McMillan Motorsports- http://www.mmsbikes.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: Mon, 27 Mar 2000 03:37:40 PST From: "mike mager" Subject: Re: MAP sensing for IR systems MysticZ replied: >Mike Mager wrote: > > Bruce, Bernd, > > thanks for the suggestions. I was hoping that there was a way to avoid >commoning the MAP source. I did leave out the aspect of the fuel-pressure >regulator reference source - very silly of me. >So use individual MAP sensors . . . I had 'brain-stormed' that (expensive!); there are no wrong answer in a brainstorming session - that's what they are for! - but very few practical ones (hey, we only need one good one!). >. . . but have a 2nd port in each runner for the fuel pressure. Or just >hook the FPR to a single runner since it's likely to be close enough to the >rest of them for a "low-tech" FPR anyway. As the others have mentioned, there would be a whole lotta pulsation, compared to Detroit's using a MAP sensor at a large plenum; a regular diaphragm type of regulator would _try_ to follow the pulsation (and would run outa bandwidth!), but we dunna want to follow _one_ cylinder's pulsations (remember, I admitted to spacing-out the fuel-pressure issue - no parts bought/cut yet!); with the proposed me-built custom ECU, the discrete, per-cylindr, MAPs could be processed to figure the desired fuel-pressure; I'm sure that there is a way to regulate with computer control (it is only more money). >The system I'm working on treats each cylinder as it's own engine, but I >only have 2 cylinders to deal with and no need for any vacuum/MAP reference >of any kind. Not the most precise way of controlling fuel, but it's close >enough. With an engine that can see 5000 rpm and 11000 rpm in under a >second there's more important things to worry about ;) Is that for your EX? I got the whole idea for a me-built ECU from an article in Circuit Cellar by a guy (reading this list?) that built one for a Formula SAE racer (four-cylinder MC engine). >MAP and MAF just aren't fast enough. Wow!, that's a consideration. What do you expect about 'speed' problems?; that Formula SAE used speed/density IIRC; are you thinking to go alpha-N? (Got to find that Formula SAE article again!) >Closed loop and loopup tables based on RPM and TPS will handle it if the >processor is fast enough. Did you mean open-loop? (Not arguing, just trying to follow!) >Now to worry about that fuel atomization issue... Huh? What? Atomization is very important, definitely, but I wonder . . . the new bikes do use EFI successfully, as does Formula One (which I know little about except up to over 17,500 RPM, and the pretty pictures in the books). Here I spill it to the list, I have a deep, dark, secret inside of me - I want to modify a Ninja engine, and a custom EFI is a part of it. Thanks, Steve, Mike >-- >Steve >97 Chevy Camaro Z28, Mystic teal, A4, not stock >90 Kawasaki EX500A4, black, M6, not even CLOSE to stock! >lt1_z28@xxx.net/~lt1_z28 >Aluminum, steel, carbon fiber, titanium, and two cast iron balls. >McMillan Motorsports- http://www.mmsbikes.com ______________________________________________________ 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: Mon, 27 Mar 2000 13:53:05 +0100 From: Corner Paul Subject: O2 sensor response times Hi This has probably been asked before - but as I can't access the archives at the moment, so... what is the typical response time for these lambda sensors ? 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 #124 ***************************** 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".