DIY_EFI Digest Tuesday, 14 May 1996 Volume 01 : Number 139 In this issue: Re: 67F687 Questions Re: Re[2]: Variable cam timing Re: Variable cam timing Batt. Voltage, 67F687 Thanks Re: 67F687 Questions Re: Variable cam timing Re: Variable Cam Timing.... Re: Variable Cam Timing.... Re[4]: Variable cam timing Variable cam timing Re[2]: Variable Cam Timing.... Re: additional injector re: Re: FPGA/CPLD software Re: search Re: Variable cam timing/phasing. SDS EFI Re: Batt. Voltage Meaurement RE: Variable Cam Timing.... Re: Injector controller (attached) Re[2]: Injector controller (attached) See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Darren McInnes Date: Mon, 13 May 1996 18:53:45 +1000 Subject: Re: 67F687 Questions Stuart Baly wrote: > I'm writing to ask a few questions about the 67F687. From what I've read > of it so far, it looks to be the bee's knees for engine control. What > I'd like to know is - > > 1. Who are the Australian distibutors for SSI? R&D Electronics (in the yellow pages under elect' components) > > 2. What package is it available in? 68 pin PLCC (Ceramic) > > 3. (The important one) How much does it cost (in AUS$)? $60.00 approx Now the bad news is that it's no longer in production according to R&D. The company I work with started developing an EFI with it about a year and a half ago, but then SSI stoped production. The only good thing about it was that I bought the old stock from Archer and have been puttering around with them for a while, trying them on a Toyota 3S-GE engine testbed. Cheers, Darren McInnes Archer Technologies ------------------------------ From: Paul Beam Date: Mon, 13 May 1996 08:54:54 -0400 Subject: Re: Re[2]: Variable cam timing At 10:47 AM 5/10/96 cdt, you wrote: > Ok so if we use a clutch or coupler to allow it to slip this would > provide a way to retard the cam but how do we then make up the > difference again?? > > John > > You would have to have one on both the cam and the crank. Slipping the crank would counteract slipping the cam. R Paul Beam Computer Systems Engineer Johnson Bible College 7900 Johnson Drive Knoxville, TN 37998 (423) 573-4517 (423) 579-2337 fax ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 13 May 1996 10:55:51 +0500 Subject: Re: Variable cam timing "ED's speech was very good and informative." Thanks, but there's also a really good collection of SAE VVA papers in SP-956 Variable Valve Actuation and Control(ISBN 1-5609103410X). Someone mentioned the valve event paper from Chrysler. I think he refers to, oops, I lent it out. Can you please post the SAE/ASME paper number? It's a very good paper which I recommend. The reason that I am dropping hints(and stopped) is because I am trying to remember if this has been patented yet and by who. Some of you are getting really close and some are getting sidetracked. If I figure out that it's been patented, then I can drop a few more. It's a very clever way of doing it. ATSAKIRI, help me out with the patent thing... Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: Jeffrey.Giberstein@xxx.EDU (Jeffrey Giberstein) Date: 13 May 96 11:23:03 EDT Subject: Batt. Voltage, 67F687 Thanks Suppose I had an A/D board and wanted to route my car battery's voltage into it for purposes of monitoring the voltage that my injectors receive. What extent of filtering or other electrical rigging is necessary in order to get a decent signal for the brain to do math with i.e., how do I do it? To John Carroll, Steve Bucholz, and Steve Ciciora. Thanks very much for your help with the 687's... we've fixed our power supply problem and the chips you have lent/donated are out of harm's way. We're leaving for Detroit today and when we return I'll let you know how we did and send you a picture of our car, etc. JG ------------------------------ From: Sandy Date: Mon, 13 May 1996 08:20:01 -0700 Subject: Re: 67F687 Questions At 04:01 PM 5/13/96 est, you wrote: >Greetings all. > >I'm writing to ask a few questions about the 67F687. From what I've read >of it so far, it looks to be the bee's knees for engine control. What >I'd like to know is - Sorry Stuart part it slated for the old part bin in the sky. It is to be discontinued very soon! Sandy ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Mon, 13 May 1996 11:37:37 +0500 Subject: Re: Variable cam timing I found that paper on valve events: Valve Events and Engine Operations SAE 820749 by T.W. Asmus Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: ducharme@xxx.com Date: Mon, 13 May 96 11:47:20 EDT Subject: Re: Variable Cam Timing.... Paul Beam wrote: > You would have to have one on both the cam and the crank. Slipping the > crank would counteract slipping the cam. Maybe I've been lurking too long, but *HOW* can you advance the cam if you use two clutches? The crank is the driving member, and de-coupling anywhere in the drive train would still retard the cam timing further. How about a "differential", i.e. a gear mixer driven by a stepper motor? You could use a planetary gear set. The crankshaft driving input would come through the sun gear, the camshaft would be attached to the planet carrier, and the stepper motor would index the ring gear to advance/retard timing. Not bad for a EE... Cliff Ducharme ------------------------------ From: Paul Beam Date: Mon, 13 May 1996 13:54:53 -0400 Subject: Re: Variable Cam Timing.... At 11:47 AM 5/13/96 EDT, you wrote: >Paul Beam wrote: > >> You would have to have one on both the cam and the crank. Slipping the >> crank would counteract slipping the cam. > > >Maybe I've been lurking too long, but *HOW* can you advance the cam if you >use two clutches? The crank is the driving member, and de-coupling anywhere >in the drive train would still retard the cam timing further. > OK. So I'm not a genius. However, it might be possible that when the valve train is released may be important -- i.e. that there are times within a cycle where the tendency of the cam is to "run away" from the crank. Some sort of centrifugal arrangement may also work with a spring that pulls the cam back when the engine decelerates. I would think that motors and gears would be far too complex to actually work reliably. R Paul Beam Computer Systems Engineer Johnson Bible College 7900 Johnson Drive Knoxville, TN 37998 (423) 573-4517 (423) 579-2337 fax ------------------------------ From: jfaubion@xxx.mil (jfaubion) Date: Mon, 13 May 96 13:44:31 cdt Subject: Re[4]: Variable cam timing I know someone will correct me if I'm wrong. Slipping the crank gear will retard the timing of the cam in relation to the crankshaft not advance it. I'm not a Mechanical Engineer, so maybe I'm missing something here, but I don't think so. John _____________________________ Reply Separator _________________________________ Subject: Re: Re[2]: Variable cam timing Author: diy_efi@xxx.edu at cs-smtp Date: 5/13/96 11:38 AM At 10:47 AM 5/10/96 cdt, you wrote: > Ok so if we use a clutch or coupler to allow it to slip this would > provide a way to retard the cam but how do we then make up the > difference again?? > > John > > You would have to have one on both the cam and the crank. Slipping the crank would counteract slipping the cam. R Paul Beam Computer Systems Engineer Johnson Bible College 7900 Johnson Drive Knoxville, TN 37998 (423) 573-4517 (423) 579-2337 fax ------------------------------ From: atsakiri@xxx.com Date: Mon, 13 May 96 15:43:34 -0400 Subject: Variable cam timing A description of some variable valve timing actuators already in production may be helpful. The following information comes directly from an article by W. Demmelbauer-Ebner, A. Dachs, and H. P. Lenz, published in the October 1991 issue of Automotive Engineering. Alfa Romeo, 2.0 l DOHC 2V - ------------------------- "Actuation of the device begins with the electronic control unit (ECU), determining timing advance based on throttle position, speed, and load. A solenoid mounted on the cover at the sprocket end of the camshaft closes a pintle valve, forcing oil pressure to build up within the device. This oil pressure forces a ring gear, which acts as an hydraulic piston, to travel axially toward the rear end of the camshaft. The outer diameter of the annular piston is mated to the sprocket by a straight spline, while the inner diameter is mated to the intake camshaft by a helical spline. Forcing the annular piston toward the rear end of the camshaft produces an angular displacement of the intake camshaft with respect to the sprocket, effectively phasing the camshaft." "When the ECU determines that retarded timing is necessary, the solenoid valve at the front end of the camshaft is opened and oil pressure on the piston is relieved." Nissan 3.0 l (also intake cam phasing) - ------------ "A solenoid valve operated by the ECU controls pressurized oil flow to the hydraulic piston to actuate phasing. Unlike Alfa Romeo's design, the annular piston has helical splines on both the inner and outer diameters, allowing more angular phasing for a given axial travel and a more compact device." Mercedes-Benz 3.0 l I-6 and 5.0 l V-8 (also intake cam phasing) - ------------------------------------- "The Mercedes-Benz system employs a double-splined hydraulic piston to alter phasing between the sprocket and camshaft ..." "The solenoid-control actuator operates a 3-way shuttle valve to minimize parasitic pressure losses, a significant difference compared to the 2-position valves of the Alfa and Nissan. As with the other two production cam phasers, timing advance is achieved by supplying solenoid-controlled pressurized oil to the annular hydraulic piston. However, retardation is achieved by applying oil pressure to the opposite side of the annular piston rather than by a return spring." Sorry for the long length. Any spelling errors are mine, not the authors'. Anthony Tsakiris - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: jfaubion@xxx.mil (jfaubion) Date: Mon, 13 May 96 16:31:22 cdt Subject: Re[2]: Variable Cam Timing.... >OK. So I'm not a genius. However, it might be possible that when >the valve train is released may be important -- i.e. that there are >times within a cycle where the tendency of the cam is to "run away" >from the crank. This might work on some engines. It would probably be very difficult to judge the timing of such an event at high RPM. > Some sort of centrifugal arrangement may also work with a spring >that pulls the cam back when the engine decelerates. This could be a possibility. >I would think that motors and gears would be far too complex to >actually work reliably. Yes I agree the KISS principle is a better plan. John ------------------------------ From: cmorris@xxx.com (Charles) Date: Mon, 13 May 1996 14:38:35 -0700 Subject: Re: additional injector You wrote: >Well we happen to have a 81 M745 laying around here too, and it does have a o2 sensor. I'd be interested in seeing that car. Are you sure it's an '81, and that it has the stock '81 L-Jetronic system? Who did the gray-market conversion? Where is the sensor mounted? What's the VIN? Besides, I never heard of an M 7-series.(although the 745i was the closest thing to it...) Feel free to e-mail me off the list... - -Charles ------------------------------ From: SRavet@xxx.com Date: Mon, 13 May 96 11:05:42 CDT Subject: re: Re: FPGA/CPLD software david chambers Wrote: | | SRavet@xxx.com wrote: | > | > I posted a note last week about the Lattice and Cypress PLD software. I am | > this close ----> <----- to buying the Cypress VHDL compiler, when I get | > it I'll tell everyone what I think of it.Just another thought, have you looked | at the maxplus software from | altera. It allows schematic input and does the compile for various | packages. I dont know how advanced the free version will let you go. We | got our copy given to us when we started using ep320 pal's. | | David Chambers | I don't think the free version does schematic input. Isn't it "AHDL" only? Also, does Altera have in-circuit programmable parts? If not then you'd have to have an expensive programmer also. - --steve Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: Frank_Mallory@xxx.com (Frank Mallory) Date: Mon, 13 May 1996 17:18:18 -0400 Subject: Re: search d> (403)274-0154 in Calgary, Alberta, Canada. For me, their's is d>the d>system to beat. Some would complain that their system is too limited d>at 8 d>bits. Compared to the complexity of correctly setting up the tables of d>a 16 d>or 32 bit system, the SDS unit is _much_ easier to tune and the d>difference d>in output between SDS and say, Electromotive or TEC or MOTEC is d>minimal; d>probably insignificant for our purposes (no one here is doing a d>DIY-F1, d>right? :-) ). d> Granted, I'm not an expert at _making_ my own EFI ECU. I have d>researched the commercial units pretty heavily, though. For <$1000 d>U.S. you d>get everything, including software and a great in-cockpit controller d>that d>lets you make adjustments in real-time and gives you major function d>readouts in real-time: manifold pressure, coolant temperature, d>ignition d>advance (including knock-retard), rpm (every 250rpm), and intake air d>temperature. The system can run open- or closed-loop. Yes, you can do d>staged injectors, which seems to be the thread du-jour. :-) d> You can't do the really trick stuff like traction control, d>etc. but d>you do get one hell of an EFI/Ignition system. Rather than explain it d>any d>further, why don't you call the number and order the info packet. They d>should include the installation/setup manual and it makes for a pretty d>good d>EFI read in and of itself. d>Cal Smith I received the brochure on the EM-1 and other systems from SDS, but I still can't figure out whether they can be applied to my mechanical CIS system. Specifically, it doesn't say what kind of throttle/manifold the SDS systems are adaptable to (except Mazda Rotary, which still covers a lot of territory). They did not send an installation/setup manual. Should I ask for more detailed literature, or what? ------------------------------ From: Digital Boy Date: Mon, 13 May 1996 20:07:57 -0700 (PDT) Subject: Re: Variable cam timing/phasing. Okay, I'm still a layman when it comes to phasing, etcetera. To my simple, confused mind, I can understand how varying the rate at which the camshaft spins, in regards to the crank, can change the timing of the valves opening and closing, but not the lift and duration of the valves. Wouldn't having control over the lift and duration be more critical than phasing change? On that note, I remember reading about hydraulic lifters in OHV engines, and how they can give somewhat the same effect as VTEC, i.e. the valves open farther/stay open longer at high RPM for a given camshaft grind. Or did I totally misunderstand their usage? If so, why isn't their usage more widespread? I'm being a bit anal here, but I want to understand this tech long before I put an engine and FI system together, (consequently spending $$$). If anyone has any papers or books to recommend, I'm listening. If they're SAE papers, a source for this info would be appreciated, as I don't think I can waltz down to the local library and order a treatise on VVT from the reference desk. Thanx, Terry ------------------------------ From: cal@xxx.com (Cal Smith) Date: Mon, 13 May 1996 21:05:40 -0600 Subject: SDS EFI >I received the brochure on the EM-1 and other systems from SDS, but I still >can't figure out whether they can be applied to my mechanical CIS system. >Specifically, it doesn't say what kind of throttle/manifold the SDS systems are >adaptable to (except Mazda Rotary, which still covers a lot of territory). They >did not send an installation/setup manual. > >Should I ask for more detailed literature, or what? Yes, ask for the install manual and aything else they can send. In regards to the first point, they sell a throttle-position switch which is attached to whatever throttle body/assembly you use to provide the throttle position input. You can also use a three-wire throttle-position sensor which is OEM on many late model imports, provided you hook up the sensor correctly to the harness. As to whether they can work with your CIS system, why don't you ask one of their techs while you have them on the phone? They can probably give you feedback you wouldn't otherwise get; even from reading the nonetheless informative installation instructions. Cal Smith ------------------------------ From: Darrell Norquay Date: Mon, 13 May 96 20:31 PDT Subject: Re: Batt. Voltage Meaurement At 11:23 AM 5/13/96 EDT, you wrote: >Suppose I had an A/D board and wanted to route my car battery's voltage into it >for purposes of monitoring the voltage that my injectors receive. What extent >of filtering or other electrical rigging is necessary in order to get a decent >signal for the brain to do math with i.e., how do I do it? > The simplest way to measure battery voltage for an A/D converter is to scale it down with a pair of resistors in voltage divider mode. This approach, however, wastes a lot of your scale, since you are not really interested in voltages below around 8V or so. The voltage divider simply divides the input voltage by a constant, giving you (say) a 0-5V output for a 0-16V input. A better approach is to subtract a fixed offset from the input, and then do your resistive divider to scale the result to 0-5V (or whatever your A/D full scale reading is). Assuming your A/D input is 0-5V, which is most common, and you want to read an input range of 8-16V, which is about right for this application, whip up a little circuit as follows: R2 Vout = (Vin - 8) X ( ------- ) / R1 + R2 |/| where Batt-----| |-------O assume Vin = 16V |\| | Vout = 5V / \ 8V R1 / Arbitrarily assign R1 = 2.0K zener \ then R2 = 3.3K / | O-----O-----Vout | | \ | R2 / --- \ --- Cap / | | | gnd --- --- This circuit will subtract a fixed 8V from the battery voltage, so for an input of 8-16V you will have 0-8V at the top of the voltage divider. Scale this down by a factor of .625, and you have 0-5V out for 8-16 V in. This will give a nice expanded scale for the input of the A/D, and increase your resolution. A 1N4738 zener has a nominal voltage of 8.2V and should do nicely for this application. The resistor values shown are the closest stock values, and actually give about 0-4.8V out. This should not have too much effect, if you are a perfectionist you could calculate values using 1% tolerance resistors for maximum accuracy. The Cap shown will add some filtering to the output voltage, the value kind of depends on how much filtering you need. Start out with a few microfarads, and if your input is too noisy, jack up the value. I would think that for this application you don't need real fast readings, you wouldn't have to adjust for voltage for each injector cycle, except maybe during cranking where it would be the most important. The cap will slow down response to fast changing voltages, so if you are sampling at a high rate, you may filter out the data of interest. Perhaps some additional software filtering by averaging a few readings together would also help. Since this has to live in an automotive environment, it may not hurt to add some transient protection in the form of a 5.6 or 6.2V zener across R2 to protect the A/D input from voltage surges, etc. Be careful with this, however, since a zener draws significant current below it's rated voltage, and may upset the operation of the divider near full scale. This is not really too much of a concern in this application, since I would think you are interested in the best accuracy at the lower end of the scale where battery voltage has the most effect on injector opening time. Hope this helps, (and the ASCII schematic survives transmission) regards dn ------------------------------ From: Andrew Dalgleish Date: Tue, 14 May 96 15:32:00 M Subject: RE: Variable Cam Timing.... You're spot on. About 6 years ago I built a proof of concept, and it works just fine. Picture a "normal" differential. Drive it on the left wheel, hold the tail shaft still, and allow the right wheel to turn. (It turns backwards, but imagine you've inserted a gear to reverse that.) Now rotate the tail shaft by some small fixed amount. Just once, not continuously. The right wheel has now had a fixed amount of rotation added (or subtracted) to it. If you keep turning the left wheel, the right wheel still turns, but now its *phase* has changed. So the power to drive the cam still comes from the crank, and only the adjustment has to be provided by a stepper motor. With a four cam desmo, the phase of each cam is individually adjustable. (As others have pointed out, you don't really need to adjust all four.) It's perfectly reliable. If the electronics fails the cam still drives, it just isn't adjustable. But it's not cheap to build. Internal tooth ring gears are expensive. Regards, Andrew Dalgleish ---------- From: owner-diy_efi-outgoing[SMTP:owner-diy_efi-outgoing@xxx.ohio-state .edu] Sent: Monday, 13 May 1996 11:47 To: diy_efi Cc: ducharme Subject: Re: Variable Cam Timing.... Paul Beam wrote: > You would have to have one on both the cam and the crank. Slipping the > crank would counteract slipping the cam. Maybe I've been lurking too long, but *HOW* can you advance the cam if you use two clutches? The crank is the driving member, and de-coupling anywhere in the drive train would still retard the cam timing further. How about a "differential", i.e. a gear mixer driven by a stepper motor? You could use a planetary gear set. The crankshaft driving input would come through the sun gear, the camshaft would be attached to the planet carrier, and the stepper motor would index the ring gear to advance/retard timing. Not bad for a EE... Cliff Ducharme ------------------------------ From: Bob Valentine Date: Tue, 14 May 1996 02:55:16 -0400 (EDT) Subject: Re: Injector controller (attached) On Thu, 9 May 1996, John S Gwynne wrote: > | (the above are formatted for HP Laser Jet printers) > "formatted for HP Laser Jet printers"... I can't wait to pipe a > 528K file to /dev/plp... I bet I end up with a stack of paper > with one or two characters on each page :). Has anyone gotten this to print on a non-genuine-HP printer? My Panasonic 4450 (Laserjet II emulation) chewed on the data for about 25 minutes, then spit out 1 blank page. Guess that's better than 100 sheets with one character on each. ;^) --> Bob Valentine <-- --> ravalent@xxx.com <-- "Experience varies directly with equipment ruined" ------------------------------ From: dzorde@xxx.au Date: Tue, 14 May 96 16:14:06 Subject: Re[2]: Injector controller (attached) I can't even get access to the net site Dan dzorde@xxx.au ______________________________ Reply Separator _________________________________ Subject: Re: Injector controller (attached) Author: diy_efi@xxx.edu at INTERNET Date: 5/14/96 3:58 PM On Thu, 9 May 1996, John S Gwynne wrote: > | (the above are formatted for HP Laser Jet printers) > "formatted for HP Laser Jet printers"... I can't wait to pipe a > 528K file to /dev/plp... I bet I end up with a stack of paper > with one or two characters on each page :). Has anyone gotten this to print on a non-genuine-HP printer? My Panasonic 4450 (Laserjet II emulation) chewed on the data for about 25 minutes, then spit out 1 blank page. Guess that's better than 100 sheets with one character on each. ;^) --> Bob Valentine <-- --> ravalent@xxx.com <-- "Experience varies directly with equipment ruined" ------------------------------ End of DIY_EFI Digest V1 #139 ***************************** 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".