DIY_EFI Digest Monday, March 6 2000 Volume 05 : Number 085 In this issue: Re: Knock sensor interface Re: Knock sensor interface Re: ECT and voltage divider help? Re: ECT and voltage divider help? Re: ECT and voltage divider help? Re: Knock sensor interface Re: ECT and voltage divider help? Re: Knock sensor interface Data Acquisition Systems, etc.. Introduction from Perth, Western Australia Re: Introduction from Perth, Western Australia OEM Black box alterations Re: OEM Black box alterations Re: Knock sensor interface Re: Introduction from Perth, Western Australia See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sun, 05 Mar 2000 09:01:58 -0500 From: Seth Subject: Re: Knock sensor interface Bernd- I have a book whritten by some VW researchers talking about "advanced technologies". The book is about 10 years old, but it has some info in it specific to the knock sensor on the 1.8 liter VW engines. I'll try to find it and see if it talks about frequencies. I am wondering if there might be a way to reverse engineer a knock sensing VW ECU? You could probably get one in a wrecking yard. In the US they run $25 to $50. If nothing else it might help decide on what ICs to use. - -Seth Bernd Felsche wrote: > > As part of the data-acquisition system I'm designing, I need to > interface to the knock sensor. > > Having browsed the diy_efi web site and found the Intersil HIP9010, > I downloaded and read the data sheet and AN9770 application note. > > Comparatively-speaking; I'm none the wiser. :-( > > How do I determine the significant background and knock sensor > frequency bandwidths? > > Should I just "suck it and see" based on "guesstimates"? > > Any pointers to relevant resources would be welcome. > > -- > 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 - ---------------------------------------------------------------------------- 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, 05 Mar 2000 09:24:57 -0500 From: Seth Subject: Re: Knock sensor interface Bernd- Didn't immediately find that book, but Introduction to Internal Combustion Engines, 2nd Edition, by Richard Stone, published by SAE has a few words to say. Page 172-173 "Forlani and Ferranti (1987) report that the signal is typically filtered with a band ass of 6-10 kHz, and examined in a window from tdc to 70 degrees after tdc. Since the cylinder is examined for a particular time window, then the knocking cylinder cna be identified, and the ignition timing retarded selectively." It refers to SAE paper 87002 A quick search of the SAE site brought up paper 980522, "Engine Knock Detection: Products, Tools and Emerging Research. I didn't see paper 87002 available for download. Good luck! - -Seth Bernd Felsche wrote: > > As part of the data-acquisition system I'm designing, I need to > interface to the knock sensor. > > Having browsed the diy_efi web site and found the Intersil HIP9010, > I downloaded and read the data sheet and AN9770 application note. > > Comparatively-speaking; I'm none the wiser. :-( > > How do I determine the significant background and knock sensor > frequency bandwidths? > > Should I just "suck it and see" based on "guesstimates"? > > Any pointers to relevant resources would be welcome. > > -- > 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 - ---------------------------------------------------------------------------- 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, 5 Mar 2000 11:38:58 -0700 (MST) From: Daniel Houlton Subject: Re: ECT and voltage divider help? Mike R Brown wrote: > >Bernd Felsche wrote: >> >> Daniel Houlton writes: >> >> >So, my question is, how do I switch something based on this voltage? >> >Basically, I want to monitor the voltage to the ECT sensor and when it >> >drops to around .4 or .5 V I want to trigger an output (that eventually >> >drives a relay). Then, while the output is triggered and the voltage >> > > Don't know what kind of thermistor is in your sensor but these guys can >be (are) very nonlinear. The common GM sensors used in the system I'm >running have very little delta_R/delta_T at the very temperature range a >person is most interested in. You can see some graphs here where I put >sensors in a thermal chamber and plotted their resistance: >http://www.sonic.net/~mikebr/plots/mat_vs_res_adc.html That plot looks to match my readings. I'm getting 2.77 kOhms cold (about 70 deg) and 270 ohms hot when the ECM is about to kick up the rpm for the engine driven fan. >What this boils down to is that the voltage ranges you are most likely >dealing with can very small. The difference between the fan on and fan >off voltages can be very small (in the order 10-100mv). Before I got Yeah, very small, but I was considering now to instead of turning it on and off between voltages, to turn it on at a certain voltage and let it run a minimum amount of time (say 30 - 60 seconds) using a 555 timer. In testing, 60 seconds will raise the voltage from .6v to around .85v. >into reverse engineering the EFI system in my car I built an analog >circuit that would turn the fan on and off at certain set points. >Problems you will run into is that a car is a very electrically noisy >environment. You need to pay attention to your input and supply >filtering. Also watch out for ground loops. My battery is in the rear >and the frame is the common return. When the fans came on (about 30 >amps inrush current) a few millivolts would develop across the frame Yeah, I noticed there was a large current at startup too. I noticed the fan came with a self-resetting circuit breaker instead of a fuse in the main power supply wire. I'm guessing that this is because a fuse would blow on startup unless you made it so big it didn't really protect the wiring system any more. >are out there looking for you. Knowing what I know now I would use the >filtering and ADC in the ECM to control these things. A small PIC or >something like Bernd suggest might be the way to go. I would like to do that as well, but I would like to complete this. I've been working on an Atmel controller for an additional injector. It's been a year now and I'm still nowhere close. I'm afraid this would turn into the same thing. thanks again, - --Dan houlster@xxx.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, 5 Mar 2000 11:24:27 -0700 (MST) From: Daniel Houlton Subject: Re: ECT and voltage divider help? Bernd Felsche wrote: > >Daniel Houlton writes: > >>I'm working on a schmatic for a small controller for an electric >>radiator fan and I have some questions on reading the ECT sensor. > >>Doing some testing on my truck I found that the sensor is fed 5V from >>the ECM (measured with the wire dis-connected from the ECT), but >>connected it only reads 3V when cold. The voltage then drops to >>around .65 V at normal operating temp. > >Looks like nominal behaviour for any NTC device. You're probably >seeing the result of a constant-current supply being used to >determine the sensor's resistance - a constant current through a >variable resistance will give a variable voltage. That was my first thought as well, but the numbers weren't agreeing. i.e. The voltage and resistance when cold gave a different current than the same readings when warm. After finding a page showing a resistor internal to the ECM and how it's set up as a voltage divider though, I did the math again to find the resistance of the unknown resistor in the ECM and I got the same answere (within a few percent anyways) with both the hot and cold readings. > >>It's not really important, but I was somewhat confused how hooking >>the wire to the ECT sensor caused the voltage to drop from 5V to 3V >>(or .7V or so when hot). After some research on the net, I found that >>it's set up as a voltage divider. > >Test the sensor in isolation; switch off the engine, unplug the >sensor and measure the resistance using a multi-meter. If the >resistance falls with increasing coolant temperature, then it's >probably an NTC resistor. Yes, this is how I measured the resistance. Unplugged the connector and measured the resistance, then plugged it back in, turned the key on and put a volt meter on it to get the voltage. And yeah, the resistance drops substantially as it warms up. > >>So, my question is, how do I switch something based on this voltage? >>Basically, I want to monitor the voltage to the ECT sensor and when it >>drops to around .4 or .5 V I want to trigger an output (that eventually >>drives a relay). Then, while the output is triggered and the voltage > >First; you need to isolate your circuit from the other one using the >same sensor. Using an op-amp is the easiest way of doing that - Op >amps have input impedances in the megaohm range. Isolating the >sensor gives you a buffered output signal - you might want to have a >small gain set up on the op-amp for convenience - else keep it at >unity. Can you give me a hint on doing this? I've been looking at a little Radio Shack book on op-amps. It give several circuits, but I don't know what they're used for. i.e., Basic Inverting Amplifier, Transconductance Amplifier, Transimpedance Amplifier, Single-Supply Amplifier, Summing Amplifier, etc. They have brief descriptions, but none indicate that they'd be used for sensing a voltage level without changing that level. Is this just a basic non-inverting amplifier? Why is a small gain a convenience? What's it do? > >You can then feed the signal into a "comparator"; an op-amp can be >used for that as well. The comparator is basical a "switch" that has >a low output when the sensed input is less than the reference >voltage, and the output is high when the sense level is higher than >reference. Depending on the op-amp, you can then drive the relay >"directly" from the comparator output. I saw the comparator circuit too. It's just an op-amp without a gain feedback right? Op-amps need + and - voltage. How would I get the - voltage? I can get 14.7V from the battery, but how do I get it to be negative as well? Also, how would I get the .6V reference that I want? Just tap into the 14.7V power and use a resistor or pot to drop it all the way to .6V? That sounds the easiest. > >>goes back up to around .7 V to turn the output back off. And I want >>to be able to fine-tune the on and off voltages with a couple pots. > >If you need hysteresis, then the circuit gets more complex. You'd need >another comparator and then combine outputs to set and reset the >corresponding driver output. There are dozens of ways of doing that; a That looks like what my little book would call a Window Comparator. Is that right? It looks like this would do that. I'm not so sure I need to though. I'm thinking now that I can just trigger the fan relay when the ECT sensor drops to about .6V (this is when the ECM first kicks up the rpm for the standard engine driven fan), then set up a 555 timer so that it runs for say 30 - 60 seconds after the voltage goes up over .6V again. (This would be a monostable or one-shot 555 configuration right?). That way it wouldn't cycle on and off so frequently. >>Also, I'm including several inputs that can trigger the fan relay like >>the A/C clutch, air compressor clutch, and a couple extras as well as >>a manual on, manual off (which over-ride the other inputs) and an >>automatic setting. > >In that case, you may be better off with a small computer with an >analogue to digital converter and several digital inputs. You then >also have the ability to drive the radiator fan at a speed according >to the load by using a pulse-width-modulated drive instead of a relay. I've been playing with Atmel controllers for running additional injectors as well, but this projects seems simple enough to not really need a micro. (Besides, I'd actually like to finish it.) >>Oh yeah, one more thing. I've found sockets for different types of >>relays in Jameco and a couple other catalogs, but they aren't very >>high amperage and I'd rather use a common automotive 30A relay. I >>can't find board mounted sockets for these automotive relays though, >>just pigtail sockets with wire leads. Anybody know where I could find >>a board mount socket for these? > >Turn the problem upside-down. See if you can fit your logic circuits >into a relay case, find a relay plate and plug it in. A relay plate >is just a moulded plastic section designed for you to plug in a >relay - you clip a few together and wire the connections as needed >using conventional automotive spade connectors. > >Auto-electricians will never guess you have a computer in one of >those tiny relay cases. :-) Actually, I did find one. A board mount socket for automotive relays in an old Newark catalog. thanks alot, - --Dan houlster@xxx.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, 05 Mar 2000 13:40:00 -0800 From: Ludis Langens Subject: Re: ECT and voltage divider help? Daniel Houlton wrote: > > They have brief descriptions, but > none indicate that they'd be used for sensing a voltage level without > changing that level. Is this just a basic non-inverting amplifier? To buffer the signal, use a "Voltage Follower". Connect the input signal to the + input. Connect the - input to the op-amp output. > Why is a small gain a convenience? What's it do? You may find it easier to work with a higher voltage in the rest of the circuit. > I saw the comparator circuit too. It's just an op-amp without a > gain feedback right? Yup. > Op-amps need + and - voltage. How would I get the - voltage? I can > get 14.7V from the battery, but how do I get it to be negative as > well? Simple, buy an op-amp that doesn't need a negative voltage. > Also, how would I get the .6V reference that I want? Just tap into > the 14.7V power and use a resistor or pot to drop it all the way to > .6V? That sounds the easiest. Regulate the 14.7 to something lower before using a voltage divider to make your reference. Does you car's computer have a 5 volt output (for a TPS or MAP)? You can use that as a reference. In fact, that is probably the best reference you can get because it should track the voltage that the ECT pullup resistor is connected to. - -- 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: Mon, 6 Mar 100 09:48:16 +0800 (WST) From: Bernd Felsche Subject: Re: Knock sensor interface Seth writes: >Bernd- >Didn't immediately find that book, but Introduction to Internal >Combustion Engines, 2nd Edition, by Richard Stone, published by SAE has >a few words to say. Page 172-173 >"Forlani and Ferranti (1987) report that the signal is typically >filtered with a band ass of 6-10 kHz, and examined in a window from tdc >to 70 degrees after tdc. Since the cylinder is examined for a particular >time window, then the knocking cylinder cna be identified, and the >ignition timing retarded selectively." >It refers to SAE paper 87002 >A quick search of the SAE site brought up paper 980522, "Engine Knock >Detection: Products, Tools and Emerging Research. Thanks heaps. I was planning on joining SAE shortly and will order those papers and at the same time. - -- 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, 6 Mar 100 10:12:47 +0800 (WST) From: Bernd Felsche Subject: Re: ECT and voltage divider help? Ludis Langens writes: >Daniel Houlton wrote: >> They have brief descriptions, but >> none indicate that they'd be used for sensing a voltage level without >> changing that level. Is this just a basic non-inverting amplifier? >To buffer the signal, use a "Voltage Follower". Connect the input >signal to the + input. Connect the - input to the op-amp output. [snip - not much to add] >> Also, how would I get the .6V reference that I want? Just tap into >> the 14.7V power and use a resistor or pot to drop it all the way to >> .6V? That sounds the easiest. Although not directly applicable here, you can also use diode forward voltages as a reference level. I've even used LEDs - different colour have different forward voltages. Also serves as an indicator and head-scratch trigger for others trying to figure out what you're doing. :-) - -- 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: Sun, 05 Mar 2000 21:15:35 -0500 From: Seth Subject: Re: Knock sensor interface Opps just noticed, I forgot the p in bandpass. Kind of changes the meaning... - -Seth Bernd Felsche wrote: > > Seth writes: > > >Bernd- > > >Didn't immediately find that book, but Introduction to Internal > >Combustion Engines, 2nd Edition, by Richard Stone, published by SAE has > >a few words to say. Page 172-173 > > >"Forlani and Ferranti (1987) report that the signal is typically > >filtered with a band ass of 6-10 kHz, and examined in a window from tdc > >to 70 degrees after tdc. Since the cylinder is examined for a particular > >time window, then the knocking cylinder cna be identified, and the > >ignition timing retarded selectively." > > >It refers to SAE paper 87002 > > >A quick search of the SAE site brought up paper 980522, "Engine Knock > >Detection: Products, Tools and Emerging Research. > > Thanks heaps. I was planning on joining SAE shortly and will order > those papers and at the same time. > > -- > 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 - ---------------------------------------------------------------------------- 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, 5 Mar 2000 22:49:03 +0800 From: Adrian Broughton Subject: Data Acquisition Systems, etc.. I've just started a project for my GT-Four (Alltrac Turbo) Celica, which is going to be a data acquisition system with a few extra bells and whistles (control water injection, warning lights, full-throttle gearshifts, turbo timer, FCD, etc). I just thought I would mention it and hopefully get some feedback or ideas from some of the people on this list, as I am a bit of a newbie when it comes to microcontrollers. I just bought a ATMEL AVR AT90S8535 microcontroller (I bought it as part of a "Hot Chip" or "ABC Mini" kit, which includes cables, Basic Compiler, Assembler, IDE and docs). From what I can see, this will do everything I need it to do, but if anybody has any thoughts or experience with this microcontroller then I'd love to hear about it (check out http://www.atmel.com for data-sheets, etc). I won't go into much detail in this post, but I've got a section of my website set up with all the details. You can see it by going to http://web.one.net.au/~gtfour/ and then clicking on the "RedBox Project" section. Any feedback, ideas, or mention of potential problems I should avoid would be greatly appreciated. Thanks Adrian ___________________________________ Adrian Broughton 1990 GT-Four Celica, 1974 VW Kombi, 1967 Holden HR Fremantle, Western Australia gtfour@xxx.au/~gtfour/ ___________________________________ - ---------------------------------------------------------------------------- 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, 06 Mar 2000 15:04:31 From: "Mike (Perth, WA)" Subject: Introduction from Perth, Western Australia Hi chaps, I've just joined and interested in EFI systems. Here is some of my b/ground, In 82 my project thesis for Western Australian Institute of Technology was to do with EFI and transmission control. Some work was done on a 72 ford escort (4 cyl 1300 side cam bowl in piston flat head crossflow n/a). Used the original inlet manifold, cut to take bosch injectors off a 2L combi using clips from a chrylser, soldered fuel rail, AFM of the same 2L combi (flap type - yuck). Made my own ECU from a Z80 4MHz, LED display, keyboard, i/o mapped, all i/face electronics were a bit basic but I did have reliable cpu/software operation. project long since abandoned as the money seemed better spent souping up the esky in all the conventional ways etc. For last few years have worked on inverters, modulated alternator field control - upgraded a Remote Area Power System (RAPS) in jungle of Sabah, eastern Malaysia, only system of its kind anywhere nearby 99% efficient charger operation - some product info on my link below along with pictures of the site and equipment (Am interested in licensing alternator based battery charging - another story). Am now designing local area paging equipment and working on my vehicle, 3L six straight nissan, auto, turbo T3 9.5psi, twin tyres front and back (looking for more - 125/85VR16 & 125/90VR16 ?). Runs OK and the RB30ET engine is a great basis for some serious mods... Though am now looking at some econoy issues as petrol is around A$86 c/litre. Have built amps for the bosch hotwire AFM (the cal maps for these change over time and the amp allows me to tune up a richer mixture on boost). Have my own electronics lab with appropriate analysers, pc, instruments etc My main interest is to install my own EFI to replace the existing bosch unit but in the same housing so its a drop in replacement - except for a daughter board to take extra injector, water injection, laptop comms, security and other nice additions. Have started a MIG course (did stick welding before) and want to put together my own exhaust twin T3. Need to move my powersteering pump and expect to run this off a 400watt ex tape servo motor (can then put in anywhere) as there's stuff all room in the engine bay and taking out the ps pump/pulley will allow nice laminar air entry straight to turbo. Will be doing a 12 to 40v inverter (40A) to run the motor at worst case low vehicle speed. Has been suggested I can spool up twin T3's faster if some water is injected into the exhaust manifold before the turbine - we'll see, when I get it done. Right now I'm interested in peripheral technical issues to do with EFI and hope to learn of your experiences and hope I can offer some alternative ideas or a different perspective. At moment I'm curious of best conversion resolution for hot-wire AFM, I've seen the 8051 projects with 8 bit resolution, I thought 10 bits would be more appropriate for multi-point as a minimum - can use an SPI 12bit and wonder if there are any comments on best AFM resolution. Oh incidentally, the output from my bosch (exisiting) AFM is log. ie. Quiescent at around 1.6v then rises logarithmically to around 5v at maximum load - anyone have any observations on this type of AFM and practicality of using log to linear i/p conditioning with their EFI front end ? Tah 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, 6 Mar 100 16:03:52 +0800 (WST) From: Bernd Felsche Subject: Re: Introduction from Perth, Western Australia Mike writes: >Hi chaps, Goodness - that makes at least three of us within shouting range. Could this be growing out of desparation due to isolation? :-) >In 82 my project thesis for Western Australian Institute of Technology was >to do with EFI and transmission control. Some work was done on a 72 ford >escort (4 cyl 1300 side cam bowl in piston flat head crossflow n/a). Used >the original inlet manifold, cut to take bosch injectors off a 2L combi using >clips from a chrylser, soldered fuel rail, AFM of the same 2L combi (flap >type - yuck). .... [snip] >My main interest is to install my own EFI to replace the existing bosch >unit but in the same housing so its a drop in replacement - except for a That's the reason I want to do data acquisition first. >daughter board to take extra injector, water injection, laptop comms, >security and other nice additions. >At moment I'm curious of best conversion resolution for hot-wire AFM, I've >seen the 8051 projects with 8 bit resolution, I thought 10 bits would be >more appropriate for multi-point as a minimum - can use an SPI 12bit and >wonder if there are any comments on best AFM resolution. Oh incidentally, >the output from my bosch (exisiting) AFM is log. ie. Quiescent at around >1.6v then rises logarithmically to around 5v at maximum load - anyone >have any observations on this type of AFM and practicality of using log >to linear i/p conditioning with their EFI front end ? Logarithmic is good because it gives you "better resolution" at, and near idle speeds. You detect the significant changes more accurately. Don't fight it - go with the flow. :-) You can set up a table to aid in the conversion of AFM output to massflow. Interpolation can be done fairly quickly so not all possible values need to be stored... otherwise with 10 bits you'd need 1024 pairs of values -- do a hash lookup, dividing by say 32 will give you only 32 pairs of values. The log-linear table will by its nature provide better quality numbers at the low end of the scale. Note that the airflow is unsteady in practice anyway; the meter output should be taken with a grain of salt. Use the feedback from the O2 sensor to close the control loop. I assume that you've read all the available Bosch documentation on the metering process. Do you have (access to) a flow-bench? The Bosch successor to L-Jetronic (flap-type) was effectively Digifant (aka L2-Jetronic). It uses the "same" flow meter. ADC is 8-bit as far as I can tell. Interestingly, the flow meter output is supposedly linear with flow-rate to simplify the task of the ECU. I'm not planning to reverse-engineer the puppy because I'm restricting my exposure to published materials in the public domain. - -- 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, 6 Mar 2000 03:09:31 -0500 (EST) From: Mary or Stephen Burgess Subject: OEM Black box alterations This is'nt exactly efi related, but none the less, it travels down an avenue most of you already have. I have, against better advice, taken apart the hermetically sealed ignitor box on my yamaha motorcycle, looking for dip switches, potentiometers, or any secret method of altering the stock ignition timing. (I'm one of those people that if they say it can't be done, I've got to try it on my own and see if I can proove them wrong) Anyhow, imagine my shock, when I found NASA mission control embedded into a small circuit board, and a Hitatchi microchip that could probably give an old IBM XT a run for it's money. No, I did not find any dip switches, or potentiometers, though I was hoping for a small note that said "to change ignition timing turn this knob clockwise=advance, anticlockwise=retard" :-) I did find an unused circuit on each of the two bipolar transistors that I believe could be of some interesting use. I have identified the "unused" circuits as R/C integrators with a resistor and capacitor fixed in a parallel with the base trigger and output of the R/C integrator is connected to the collector. I'm no genius when it comes to electronics, but what it looks like to me is that this "unused" circuit has one of several functions. - - to eggagerate ringing in the ignition coils and effectively create a multiple spark ignition. - - to counteract impedance in the coils, and effectively eliminate ringing in the igntion coils. - - to advance ignition by the amount of time it takes to charge the capacitor (based on a function of both resistance and capacitance - R-C time constant???) I looked at this for quite some time, and I think the bipolar transistors are being used as filters, a saw tooth signal is sent to the base, and as the frequency of the sawtooth increases it's amplitude decreases, effectively creating a rev limit when at 12500 rpm the amplitude of the sawtooth is insufficient to trigger the transistor i.e. less than 0.5V - - the R/C circuit could also serve a function of increasing rev limit with a small capacitor adding a "second cap" on the sawtooth and increasing it's amplitude. Like I said I'm no electronic wizz, and it took me days to come up with a few speculative guesses as to it's possible uses, and so with no sure way to decide (replacement units are $300, and it has to come from Japan so there's a 4 month wait - try it and see is out!!!) I am consulting those of you with actual electronics background and experience with this type of thing (that is altering stock ignition modules) I tried to describe the circuit as best as I could, but I have drawn it out if anyone does'nt immediately recognise it's purpose, and want's or needs to see it, I can attach it to an email to that person, I don't want to upload pictures to the list, especially since it's not directly related to efi. Type to you later! Steve - ---------------------------------------------------------------------------- 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, 06 Mar 2000 02:58:30 -0600 From: MysticZ Subject: Re: OEM Black box alterations Mary or Stephen Burgess wrote: > > Like I said I'm no electronic wizz, and it took me days to come up with a > few speculative guesses as to it's possible uses, and so with no sure way to > decide (replacement units are $300, and it has to come from Japan so there's > a 4 month wait - try it and see is out!!!) I am consulting those of you with > actual electronics background and experience with this type of thing (that > is altering stock ignition modules) I'm definately no electro-genius (suspension is my thing ;), but I do have a feeling that the best way to do this is either: 1> Build a new ignition box that has the adjustability built in, probably by retarding the ignition an extreme amount so that the retard actually becomes advance (retard it 710 degrees and it actually advances 10 degrees, get it?) or, b> do it mechanically by either buying a ready-made advancer (Factory, V&H, etc.) or modifying a stock ignition rotor to be adjustable (buy two, hack, grind, weld, and machine into one) Personally I plan on going with b until I get farther with the fuel injection setup for my 2 cyl. Ninja motor when I can integrate idea 1 into the brain. - -- 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, 06 Mar 2000 01:11:37 PST From: "mike mager" Subject: Re: Knock sensor interface Greetings! Could you give me the URL (or a good clue!) to that AN9770, as the search at Intersil couldn't find it. Cool circuit! (Time marches on.) Thanks, Mike >From: Bernd Felsche >Reply-To: diy_efi@xxx.org >To: diy_efi@xxx.org >Subject: Knock sensor interface >Date: Sun, 5 Mar 100 17:53:32 +0800 (WST) > >As part of the data-acquisition system I'm designing, I need to >interface to the knock sensor. > >Having browsed the diy_efi web site and found the Intersil HIP9010, >I downloaded and read the data sheet and AN9770 application note. > >Comparatively-speaking; I'm none the wiser. :-( > >How do I determine the significant background and knock sensor >frequency bandwidths? > >Should I just "suck it and see" based on "guesstimates"? > >Any pointers to relevant resources would be welcome. > >-- >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 > ______________________________________________________ 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, 06 Mar 2000 18:37:05 From: "Mike (Perth, WA)" Subject: Re: Introduction from Perth, Western Australia At 04:03 PM 6/03/2000 +0800, you wrote: >Goodness - that makes at least three of us within shouting range. Yeah hi Bernd, surprised to found that out after I posted :) Saw the first ref back some time back but never had enough time to follow it up - I'm committed (?) to getting something bit mroe serious done to my car this year... Hence building a twin T3 exh manifold, need more MIG practice though, >Could this be growing out of desparation due to isolation? :-) hehe - Possibly, Perth is after all the most isolated capital city in the world (At first I thought you were from Perth Scotland, been there once). >>My main interest is to install my own EFI to replace the existing bosch >>unit but in the same housing so its a drop in replacement - except for a > >That's the reason I want to do data acquisition first. mmm Yeah - should be possible to 'hang off' a simple 4 channel analog and perhaps 4 channel digital with time ref for a few hundred. Trouble is the damn connectors can only be sourced from wreckers :( So I'd use those tiny probe clips (open ECU, attach, close, run cables out to pluggable block), that means minimal upset of existing circuit. I remember the days I'd be in the back seat with my HP analyser, 12v inverter, buddy in front seat - I'd say 'gun it' and me hastily pressing buttons on the woeful user interface on the HP whilst seeing the trace jump around ~`:o >>At moment I'm curious of best conversion resolution for hot-wire AFM, I've >>seen the 8051 projects with 8 bit resolution, I thought 10 bits would be >>more appropriate for multi-point as a minimum - can use an SPI 12bit and >>wonder if there are any comments on best AFM resolution. Oh incidentally, >>the output from my bosch (exisiting) AFM is log. ie. Quiescent at around >>1.6v then rises logarithmically to around 5v at maximum load - anyone >>have any observations on this type of AFM and practicality of using log >>to linear i/p conditioning with their EFI front end ? > >Logarithmic is good because it gives you "better resolution" at, and >near idle speeds. You detect the significant changes more accurately. >Don't fight it - go with the flow. :-) Oh yes - understand that - especially at light cruise I'm on somewhere like 10-15% throttle and quite happy with the bosch cpu for smoothness but can't do anything to it to improve injectors etc. I'm interested in the signal conditioning electronics, the Bosch ECU has a large PCB area (and a proprietary hybrid) devoted to the AFM output before it goes into a 6803 8bit micro. If a regular a/d were used then this hybrid could be redundant - I'm therefore curious as to why boscj did it that way and hence my query about the 8bit - if that shed some light on the rationale ? >You can set up a table to aid in the conversion of AFM output to >massflow. Interpolation can be done fairly quickly so not all >possible values need to be stored... otherwise with 10 bits you'd >need 1024 pairs of values -- do a hash lookup, dividing by say 32 >will give you only 32 pairs of values. The log-linear table will by >its nature provide better quality numbers at the low end of the >scale. Yes understood, perhaps I should have been more specific in my query, I'm curious if 8bits were sufficient resolution for the throttle body system as against using say a 12bit for multipoint (with perhaps a little more flow and precision) ? A lookup table with 12 bits would be OK but I suppose I'm curious what the conventional wisdom is here - do most late 80's,early 90's ecu's use 10, 12 bits and/or did they use opamps to convert to linear then a/d or simply a/d the log o/p of the AFM ? >Note that the airflow is unsteady in practice anyway; the meter >output should be taken with a grain of salt. Use the feedback from >the O2 sensor to close the control loop. Yeah sure, I was thinking some correction with MAP too. Just how unsteady is that output - as a result of positive feedback effects on normal turbulence at the inlet piping - on my VL its woeful - theres a real bad sprung pipe behind the AFM and huge pipe discontinuity in front :( ? It would be ideal to have it run in feedback loop with a derivable signal from the dyno - that would be nice - I guess its been done before though, ie. Dyno feedback to ECU 'locks in' range for max power etc :) ? >I assume that you've read all the available Bosch documentation on >the metering process. Do you have (access to) a flow-bench? Yes, have docs from 1982 but don't have a flow bench - not too much involved though, was going to put one together in next few weeks in my sleepout, hope it won't wake the neighbours, now looking for a single phase motor and centrifugal air pump >The Bosch successor to L-Jetronic (flap-type) was effectively >Digifant (aka L2-Jetronic). It uses the "same" flow meter. ADC is >8-bit as far as I can tell. Interestingly, the flow meter output is >supposedly linear with flow-rate to simplify the task of the ECU. mmm OK - I thought the 'L' in 'L-jetronic' generally referred to air metering, hence this included platinum hot wire - true mas air flow etc but with general log output ? >I'm not planning to reverse-engineer the puppy because I'm >restricting my exposure to published materials in the public domain. Fair enough, what-ever's the most practical I suppose. Although 8bit conversion across whole range is real elegant, I like the idea of precision and have some experience with kalman filters, these might end up with a 10bit corrected AFM from a 12bit raw etc... ie Might drop the low 2 bits into a correction formula whilst using top 8 bits as raw table lookup... You see, to fit in the existing ECU enclosure I'd like to keep the hardware count as low as possible - if I can use the onchip flash instead of external bus devices then I have a smaller (simpler) PCB, more IO lines etc etc... At some point I'd like to run CNG - given its only $12 per 200K as against $60 per 400K for petrol and I could fill up at home with a compressor off the gas line - see Sunday times Auto section - 5th March... Interesting. Anyone done gas EFI on this group or know of any links to that ? Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- 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 #85 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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