From Diy_Efi-Owner Tue May 10 16:09:54 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25280; Tue, 10 May 94 16:09:54 GMT Received: from relay1.UU.NET by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA25274; Tue, 10 May 94 12:09:50 -0400 Received: from camelot.dsccc.com by relay1.UU.NET with SMTP (5.61/UUNET-internet-primary) id AAwpho24641; Tue, 10 May 94 12:09:47 -0400 Received: from sun001.dsccc.com (spd.dsccc.com) by camelot.dsccc.com (5.65c/SMI-V1.8) id AA13265; Tue, 10 May 1994 11:12:23 -0500 Received: from aplo1.dsccc.com by sun001.dsccc.com with SMTP id AA09171 (5.65c/IDA-1.4.4 for ); Tue, 10 May 1994 11:12:26 -0500 Received: by aplo1.dsccc.com id AA08330 (5.65c/IDA-1.4.4 for DIY_EFI@coulomb.eng.ohio-state.edu); Tue, 10 May 1994 11:09:02 -0500 Date: Tue, 10 May 1994 11:09:02 -0500 From: John Jennings Message-Id: <199405101609.AA08330@aplo1.dsccc.com> To: DIY_EFI In-Reply-To: DIRK BROER's message of Tue, 10 May 1994 11:16:31 -0400 (EDT) <940510111631.2dc04180@STDVAX.GSFC.NASA.GOV> Subject: A Proposal Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI > So what to do? > > How about this: > 1) We finalize the requirements document - including the ability for the From Diy_Efi-Owner Tue May 10 16:38:07 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25333; Tue, 10 May 94 16:38:07 GMT Received: from relay1.UU.NET by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA25327; Tue, 10 May 94 12:38:06 -0400 Received: from camelot.dsccc.com by relay1.UU.NET with SMTP (5.61/UUNET-internet-primary) id AAwphq01883; Tue, 10 May 94 12:36:58 -0400 Received: from sun001.dsccc.com (spd.dsccc.com) by camelot.dsccc.com (5.65c/SMI-V1.8) id AA13667; Tue, 10 May 1994 11:39:34 -0500 Received: from aplo1.dsccc.com by sun001.dsccc.com with SMTP id AA09572 (5.65c/IDA-1.4.4 for ); Tue, 10 May 1994 11:39:37 -0500 Received: by aplo1.dsccc.com id AA08343 (5.65c/IDA-1.4.4 for DIY_EFI@coulomb.eng.ohio-state.edu); Tue, 10 May 1994 11:36:10 -0500 Date: Tue, 10 May 1994 11:36:10 -0500 From: John Jennings Message-Id: <199405101636.AA08343@aplo1.dsccc.com> To: DIY_EFI In-Reply-To: DIRK BROER's message of Tue, 10 May 1994 11:16:31 -0400 (EDT) <940510111631.2dc04180@STDVAX.GSFC.NASA.GOV> Subject: A Proposal Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Please disregard my previous message (apparently mail server doesn't like "." as the 1st char in a line). > So what to do? > > How about this: > 1) We finalize the requirements document - including the ability for the . . > 4) We have discussions on algorithms, come up with programming aids or even > programming routines. > > So what do you say? Sounds like a plan! I like it! JJ ----------------------------------------------------------------------- John Jennings INTERNET: jjenning@spd.dsccc.com DSC Communications, Corp. (214) 519-3957 1000 Coit Road, Plano TX 75075 From Diy_Efi-Owner Tue May 10 17:28:36 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25802; Tue, 10 May 94 17:28:36 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA25796; Tue, 10 May 94 13:28:34 -0400 Message-Id: <9405101728.AA25796@coulomb.eng.ohio-state.edu> To: DIY_EFI Subject: Re: DIGEST FORMAT? (pleasePLEASEpleasePLEASE) Date: Tue, 10 May 94 13:28:34 -0400 From: John S Gwynne Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI In message , you write: | greetings: | the subject says it all. can we get the list in digest format? i'm getting | a bit tired of hacking 20-some-odd lines off each message i want to save... Maybe latter.... try piping it through something like SED or make at little pearl script to remove your headers.... John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- From Diy_Efi-Owner Tue May 10 20:06:34 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA27299; Tue, 10 May 94 20:06:34 GMT Received: from dopey.cc.utexas.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA27293; Tue, 10 May 94 16:06:30 -0400 Received: (from efrank@localhost) by dopey.cc.utexas.edu (8.6.8.1/8.6.6/cc-wf-sunos.mc-1.1) id PAA02090; Tue, 10 May 1994 15:06:25 -0500 Date: Tue, 10 May 1994 15:06:23 -0500 (CDT) From: The_Mechanic Subject: Re: Crank position sensor To: DIY_EFI Cc: DIY_EFI In-Reply-To: <01HC5JSQBAZI8Y5YZY@Jetson.UH.EDU> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I don't think taht magnets are the best solution. First, as sated below, they can be somewhat difficult to install on engines other than small block chevys with harmonic balancers. Second, I don't think that the resolution is that great. What about the 60 tooth wheel/sensor setup? How hard would it be to use this, and is there anything to gain from it? Erik On Tue, 10 May 1994 ST3XD@Jetson.UH.EDU wrote: > Assuming we will hammer out the controller, the first and most basic > sensor we need is the crank position sensor. If we are going to make > a true SEFI system with distributorless ignition, a highly accurate > crank position sensor is a must. > > But how? > > I've seen some setups using magnets, but how can these be installed? > Do holes need to be drilled in the harmonic balancer with little > magnets placed in them? That's the only way I can come up with. > The racing setups are great, but we have to install this on our > engine with minimal (hopefully) modification. > > From Diy_Efi-Owner Tue May 10 22:56:59 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA28152; Tue, 10 May 94 22:56:59 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA28145; Tue, 10 May 94 18:56:56 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q10ja-000AVTC; Tue, 10 May 94 17:57 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: crank sensors To: DIY_EFI Date: Tue, 10 May 1994 17:57:06 -0500 (CDT) In-Reply-To: <9405101528.AA25017@coulomb.eng.ohio-state.edu> from "John S Gwynne" at May 10, 94 11:28:23 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1839 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI John S Gwynne writes: > Micro Switch (made by MG magnets?) makes what looks like a small socket > head screw (rather: a screw with a magnet in the end) that could easily be > placed in the harmonic balancer. I would want to use a horizontal mill > to properly locate the holes, but if you hand selected four (V8) equally > weighted magnets, I would not be concerned with the balance (IMHO). The last > concern is how strong are they. I have not bought any yet, so I don't know > for sure if it would handle high revs (the catalog I have doesn't give > a spec. for this). I suspect it would. I like flying magnet approach. I've used both tooth wheel (electromotive [puke]), and flying magnets (EFI Technologies) and the flying magnets win hands down. You can adapt flying magnets to anything. Either put them directly in the crank pulley or balancer, or mount them in a plate sandwiched somewhere. Adjust TDC by moving the sensor. To mark the compression stroke on cylinder #1, put a single flying magnet on the cam (or in the distributor). The timing on the cam sensor is non-critical, it just tells the controller that the next crank pulse is TDC on cylinder 1. The machining involved is really simple, you could probably do all of it with a drill press and a hacksaw. Someone could probably come up with some fairly universal hardware. As far as high RPM goes, we had four 1/8" by 3/4 inch magnets in the blower drive pulley (4" diameter) on our Kawasaki ZX-6. The magnets were a slip fit 3/8" into the pulley, and retained with JB Weld (they were supposed to have been a press fit, someone screwed up :). Anyway, they held 15,000rpm with no problem. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / pile of junk! 80 Toyota Celica - 20R / 5spd From Diy_Efi-Owner Wed May 11 03:49:19 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29704; Wed, 11 May 94 03:49:19 GMT Received: from uahcs2.cs.uah.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA29698; Tue, 10 May 94 23:49:17 -0400 Received: by uahcs2.cs.uah.edu (Smail3.1.28.1 #3) id m0q15IM-00011wC; Tue, 10 May 94 22:49 CDT Message-Id: Date: Tue, 10 May 94 22:49 CDT From: kking@cs.uah.edu (Ken King) To: diy_efi Subject: additional features... Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI greetings: howza-bout some security features? things like an idle-thru-35mph map that can be activated w/ a switch (for vallet,...), perhaps a second switch for a lesser performance map (for the teenager on a date...). also a real security interface - some sort of key-fob activated switch that won't let you start the car w/o it (or a combination entered, or a 'credit card' swipe,...) lets see.... i've got one computer for security/alarm, one for enging sensor management, one controlling ignition pulses and a fourth for the fuel injection. can anyone think of somehting i missed (i told you that the cost to finish my project doubled when my wife got that @$#%*! jeep) later, kc 69 nova (all over the garage) 77 aspen slant-6 (rusting in the driveway) From Diy_Efi-Owner Wed May 11 04:14:37 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29914; Wed, 11 May 94 04:14:37 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA29908; Wed, 11 May 94 00:14:32 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q15gv-000AVPC; Tue, 10 May 94 23:14 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: additional features... To: DIY_EFI Date: Tue, 10 May 1994 23:14:41 -0500 (CDT) In-Reply-To: from "Ken King" at May 10, 94 10:49:00 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 769 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Ken King writes: > howza-bout some security features? things like an idle-thru-35mph map > that can be activated w/ a switch (for vallet,...), perhaps a second switch > for a lesser performance map (for the teenager on a date...). > > also a real security interface - some sort of key-fob activated switch > that won't let you start the car w/o it (or a combination entered, or a > 'credit card' swipe,...) I feel that things such as this are outside of the scope of the project. One of the point features of this system I hope will be that you could add these types of things on your own. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / pile of junk! 80 Toyota Celica - 20R / 5spd From Diy_Efi-Owner Wed May 11 16:21:39 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA01659; Wed, 11 May 94 16:21:39 GMT Received: from aztec.al.bldrdoc.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA01653; Wed, 11 May 94 12:21:37 -0400 Message-Id: <9405111621.AA01653@coulomb.eng.ohio-state.edu> Date: 11 May 1994 10:22:21 -0700 From: "Ciciora Steve" Subject: DYI-EFI how to book To: DIY_EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Over on the Hotrod mailing list, John mentioned a book about how to roll your own EFI system using a comminly available single board computer, complete with source code! I've posted messages twice to that list asking John for the Name of the Book and Author, but he has not replied. Mabe the info is unavailable due to his upcoming move. Does anyone else out there know anything about this book? I don't want to be a pain in the ass, so I'm not going to ask him again, but could someone else ask him if they feel that it's approprate? - Steven Ciciora From Diy_Efi-Owner Wed May 11 16:30:22 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA01721; Wed, 11 May 94 16:30:22 GMT Received: from aztec.al.bldrdoc.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA01715; Wed, 11 May 94 12:30:20 -0400 Message-Id: <9405111630.AA01715@coulomb.eng.ohio-state.edu> Date: 11 May 1994 10:32:11 -0700 From: "Ciciora Steve" Subject: To: DIY_EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI In a previous post John S Gwynne writes: ... For instance, I have a small circuit to measure RPM that simply plugs into the tach port of my MSD unit. It's just a simple state machine based in a GAL chip that controls a 82C54 (10MHZ programmable timer) with a high speed comparator/conditioner (ok, looks like 14 components for conditioning and surge protection). Its use is simple and does not require CPU intervention. For everyone interested in taking advantage of this circuit and knowing that we will never get everyone to agree upon the same CPU, it would be to our advantage if we could agreed upon a common bus structure that would be compatible with each of these small sensor interface circuits... Well, John, I for one am interested in using your circuit! How can you tell us more info? Is there a place where you could post the sch. and GAL equations? I have access to HP laser printers, HP ploters, etc. so whatever form you can post the info, I should be able to make a hard copy. If don't want to hassle with this, if you US mail me, I'll foward the info to others who are interested. As soon as I finish moving (less than a month) and find my info, I'll re-pay the favor and post everything I know about my 6811 based distributorless ignition system I did for a senior project... - Steven Ciciora From Diy_Efi-Owner Wed May 11 18:44:16 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA02397; Wed, 11 May 94 18:44:16 GMT Received: from ZEUS.TAMU.EDU by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA02391; Wed, 11 May 94 14:44:11 -0400 Date: Wed, 11 May 1994 13:44:09 -0500 (CDT) From: TEB0958@ZEUS.TAMU.EDU To: DIY_EFI Message-Id: <940511134409.2206b981@ZEUS.TAMU.EDU> Subject: RE: DYI-EFI how to book Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI if you ever do get a copy i sure would like a copy myself. -tom From Diy_Efi-Owner Wed May 11 22:21:22 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA03485; Wed, 11 May 94 22:21:22 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA03479; Wed, 11 May 94 18:21:20 -0400 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #6) id m0q1Mac-0002czC; Wed, 11 May 94 17:17 CDT Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #8) id m0q1Mab-000pdhC; Wed, 11 May 94 17:17 CDT Message-Id: Received: by bangate.compaq.com with VINES ; Wed, 11 May 94 17:17:23 CDT Date: Wed, 11 May 94 17:16:07 CDT From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: knock sensors To: diy_efi Cc: Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I'd like to start a discussion of knock sensors. So, I'll ask some questions: How do they work? Is there a simple aftermarket solution, and is it the kind of thing that someone could build themselves? How would one implement one? Here is something I came up with that is probably way to complex for the task: Apply a strip of piezo-electric tape to the head or other suitable place. Piezo-electric tape picks up vibrations and outputs a small (tiny) corresponding voltage signal. Amplify this, and analyze the signal. A normal running engine should produce a characteristic frequency distribution. One that is knocking should produce a different one (perhaps more high frequency?) Anyway, figure out where the difference is in the frequency range, and watch that particular band with an analog filter. This should work, but seems complex, and also would probably differ greatly from engine to engine. I would like to hear comments from people with knowledge of how commercial knock detectors work. thanks! --steve sravet@bangate.compaq.com From Diy_Efi-Owner Thu May 12 00:33:05 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA03833; Thu, 12 May 94 00:33:05 GMT Received: from pine.cse.nau.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA03827; Wed, 11 May 94 20:33:03 -0400 Received: (from met@localhost) by pine.cse.nau.edu (8.6.9/2.2-nau) id RAA02659 for diy_efi@coulomb.eng.ohio-state.edu; Wed, 11 May 1994 17:33:01 -0700 Message-Id: <199405120033.RAA02659@pine.cse.nau.edu> From: met@pine.cse.nau.edu (MTN-KAT) Date: Wed, 11 May 1994 17:33:00 -0700 X-Mailer: Mail User's Shell (7.2.5 10/14/92) To: diy_efi Subject: Crank Position via Hall Effect Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I know that this isn't going to please everyone, but it is the way I am looking to solve my crank position problem. I can cut into my flywheel before it is put into the car and with four magnets there is not a problem with balancing. My idea is to use 4 magnets mounted IN the flywheel, with one reversed w/r to pole direction. Using the hall effect I think that we could detect the reverse clip. This would indicate tdc for two cylinders and with an inductive pickup on plug wire #1 we could determine firing order. Placement of the magnets should be say 35 degrees advanced, the timer function could be used to determine the optimum firing w/r valve opening. (for SEFI). Placement on the flywheel allows for MUCH more accurate timing, the velocity with which the magnet would pass the pickup will narrow the signal pulse by around 350% in my particular case, 7" HB vs 24" flywheel. Millam From Diy_Efi-Owner Thu May 12 01:59:09 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA04067; Thu, 12 May 94 01:59:09 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA04061; Wed, 11 May 94 21:59:07 -0400 Message-Id: <9405120159.AA04061@coulomb.eng.ohio-state.edu> To: DIY_EFI Subject: Re: Crank Position via Hall Effect In-Reply-To: Your message of "Wed, 11 May 94 17:33:00 PDT." <199405120033.RAA02659@pine.cse.nau.edu> Date: Wed, 11 May 94 21:59:06 -0400 From: John S Gwynne Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI -------- In message <199405120033.RAA02659@pine.cse.nau.edu> , you write: | Placement on the flywheel allows for MUCH more accurate timing, the velocity | with which the magnet would pass the pickup will narrow the signal pulse by | around 350% in my particular case, 7" HB vs 24" flywheel. I don't fully agree... While I agree the angular velocity is greater, what really count is the "turn on" time. Presumably, we would be doing rising or falling edge detection with a high speed comparator with hysteresis. The threshold voltage would be picked as the voltage with the highest derivative (point on the curve with the fastest rise). This would result in the most stable triggering point. As such the actual dwell time of the sensor in the presence of the magnet field is unimportant. What count is the turn on/off times which are really set, at the speeds we are dealing with, by the device and the gain in the system. This necessitates the selection of a good high speed transducer and comparator. Don't miss understand me, I like the idea; but the "much more accurate" statement maybe should be "a little more accurate". John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- From Diy_Efi-Owner Thu May 12 12:45:00 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA05795; Thu, 12 May 94 12:45:00 GMT Received: from mn.ecn.purdue.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA05789; Thu, 12 May 94 08:44:58 -0400 Received: from mn.ecn.purdue.edu (armfield@localhost) by mn.ecn.purdue.edu (8.6.8/3.4davy) id HAA19254; Thu, 12 May 1994 07:44:50 -0500 Message-Id: <199405121244.HAA19254@mn.ecn.purdue.edu> Date: Thu, 12 May 1994 07:44:50 -0500 From: Jeffrey S Armfield To: DIY_EFI Subject: Re : Knock Sensors Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Knock sensors are basically just cheap accelerometers. They respond to vibration by generating a voltage. There are three basic types - resonant , flat response, and broadband resonant - which differ in their frequency response characteristics. Resonant sensors have a sharp response at a given frequency - if the engine does not knock at that frequency then you'll never know it. Flat\ response knock sensors are just that - they have low output (typically a few mV/g accel.) over a broad frequency range. They usually require amplification of some sort and more extensive filtering. Broadband resonant sensors are an attempt to take the best of the flat response and resonant sensors and combine them into one package. Broader response than resonant (peak response is spread over 2-3 kHz) with higher output that flat response sensors. I believe AC-Delco makes these type of sensors. As far as a knock control system goes, knock occurs somewhere between 5 kHz and 8 kHz (from my experience) and the most important item to locate the sensor in a place that won't pick up stray vibration. A crude knock control algorithm listens for output from the sensor of sufficient amplitude and then alters the timing. There's not really any black magic in knock detection and control - just some signal processing and good engineering in locating the sensor. Jeff Armfield