From owner-diy_efi Wed Nov 2 05:16:19 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA10901; Wed, 2 Nov 94 05:16:19 GMT Received: from aztec.co.za by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA10896; Wed, 2 Nov 94 00:16:07 -0500 Received: by aztec.co.za (Smail3.1.28.1 #5) id m0r2Y2p-000KeHC; Wed, 2 Nov 94 07:15 EET Date: Wed, 2 Nov 1994 07:15:34 +0200 (SAT) From: Wouter de Waal Subject: To: diy_efi Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI get diy_efi libgcc_m68000 end From owner-diy_efi Wed Nov 2 07:12:22 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA11541; Wed, 2 Nov 94 07:12:22 GMT Received: from aztec.co.za by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA11536; Wed, 2 Nov 94 02:12:13 -0500 Received: by aztec.co.za (Smail3.1.28.1 #5) id m0r2Zr9-000KfVC; Wed, 2 Nov 94 09:11 EET Date: Wed, 2 Nov 1994 09:11:39 +0200 (SAT) From: Wouter de Waal Subject: Oops! To: DIY_EFI In-Reply-To: Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Sorry, my mistake! Local time when I sent that request was 07:30, so I wasn't awake yet. Wouter From owner-diy_efi Wed Nov 2 10:14:26 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA11752; Wed, 2 Nov 94 10:14:26 GMT Received: from hermes.intel.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA11747; Wed, 2 Nov 94 05:14:18 -0500 Received: from PTD.intel.com by hermes.intel.com (5.65/10.0i); Wed, 2 Nov 94 02:04:24 -0800 Date: Wed, 2 Nov 94 02:14:17 PST From: YOU LOOK LIKE A MILLION BUCKS - ALL GREEN & WRINKLY. Message-Id: <9411021014.utk5875@PTD.intel.com> X-To: HERMES::"DIY_EFI@coulomb.eng.ohio-state.edu" Subject: MCU choices To: DIY_EFI Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Hi all, I just subscribed to the list, so forgive me if this has been discussed before. I plan to design and build an EFI system for my '56 Chevy Pickup and I am wondering which Motorola microcontroller would be my best choice. I have a lot of experience with the HC11, but I have not used the 68HC16 and 6833X devices, which look quite useful. From owner-diy_efi Wed Nov 2 13:48:47 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12236; Wed, 2 Nov 94 13:48:47 GMT Received: from sbctri.tri.sbc.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA12231; Wed, 2 Nov 94 08:48:45 -0500 Received: from wedge (wedge.tri.sbc.com) by sbctri.sbc.com (4.1/SMI-4.1) id AA07764; Wed, 2 Nov 94 07:38:16 CST From: tadams@sbctri.sbc.com (Tom. Adams 529-7860) Message-Id: <9411021338.AA07764@sbctri.sbc.com> Subject: Re: The files... To: DIY_EFI Date: Wed, 2 Nov 1994 07:49:49 -0600 (CST) In-Reply-To: <9411020416.AA10309@coulomb.eng.ohio-state.edu> from "John S Gwynne" at Nov 1, 94 11:16:11 pm X-Mailer: ELM [version 2.4 PL22] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Content-Length: 497 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI > experience. I have chosen to work with the 68000 since it is the > cheapest entry into the m68k family that opens the door to a great > deal of GNU software (gcc, gas, binary utilities, glibc, gdb,...) and > the RTEMS kernel. I encourage others to work with the CPU of their > choice, and hopefully we can all share information on interfacing and > control algorithms. Could you share more information about your development environment? What you're using, any changes you needed to make, etc. From owner-diy_efi Wed Nov 2 14:26:03 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12455; Wed, 2 Nov 94 14:26:03 GMT Received: from access4.digex.net by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA12450; Wed, 2 Nov 94 09:25:59 -0500 Received: by access4.digex.net id AA25602 (5.67b8/IDA-1.5 for DIY_EFI@coulomb.eng.ohio-state.edu); Wed, 2 Nov 1994 09:25:45 -0500 From: Andy Harrah Message-Id: <199411021425.AA25602@access4.digex.net> Subject: Injected Briggs To: DIY_EFI Date: Wed, 2 Nov 1994 09:25:45 -0500 (EST) X-Mailer: ELM [version 2.4 PL24beta] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 575 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Jeff, I've been interested in trying to inject a small engine, too. I've rigged up an gutted alternator from a VW Rabbit to a 5 HP Tecumseh to use as a brake for a dyno. I've kludged the thing by shorting the three legs of the windings to form an eddy-current brake. The load is easily adjusted via the field current. The problem, of course, is the heat produced. I have successfully run the ignition from a magnetic TDC reference sensor. Anyway, exactly what injector have you found that is small enough to work on these small displacement engines. .../Bill Lewis From owner-diy_efi Wed Nov 2 14:30:31 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12476; Wed, 2 Nov 94 14:30:31 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-1.92/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 AA12471; Wed, 2 Nov 94 09:30:29 -0500 Message-Id: <9411021430.AA12471@coulomb.eng.ohio-state.edu> To: DIY_EFI Subject: Re: MCU choices In-Reply-To: Your message of "Wed, 02 Nov 94 02:14:17 PST." <9411021014.utk5875@PTD.intel.com> Date: Wed, 02 Nov 94 09:30:29 -0500 From: John S Gwynne Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI -------- In message <9411021014.utk5875@PTD.intel.com> , you write: | Hi all, I just subscribed to the list, so forgive me if this has been discuss | ed | before. I plan to design and build an EFI system for my '56 Chevy | Pickup and I am wondering which Motorola microcontroller would be my best | choice. I have a lot of experience with the HC11, but I have not used the | 68HC16 and 6833X devices, which look quite useful. This just came up a day or two ago in comp.sys.m68k. I'm forwarding some of it for those that don't read that group. ============== cut here ================= Matthew P. Downs (mpd@adc.com) wrote: : wj-wray@uwe.ac.uk (WJ Wray) writes: : >Motorolas marketing pushes the 683** series as the top of the range : >microcontrollers while the 68HC16 is an upgrade path for 68HC11 users. HC16 is marketed as an upgrade path for HC11, however, there are enough differences to make the migration difficult. For example, any stack manipulation instructions will have to be re-coded. : >Looking at the data the HC16 seems to spank the CPU32 on most counts, : >particularly with the `DSP' features. On top of this it is cheaper, : >sucks less current and the Z1 variant includes an ADC (also featured : >on the '333 if you can get your hands on one & afford to pay). I have used both HC16 and CPU32 based HC3xx. One thing that impress me about HC16 is that it is a very 'fast' CPU; most commonly used instructions are coded within 16-bit, therefore, needed only one memory fetch, coupled with the 'fast-termination' cycle and a 16,78MHz clock rate and a 3 instruction pipeline, it profiled 119.2ns per instruction at very high percentage of the time! The other major different between CPU32 and HC16 is that CPU32 cannot do non-align memory cycles properly. Only the later version of HC3xx family which are based on a modified 020 core is able to do that. One interesting note is that the HC16 is about twice as fast as an Intel 186 running at the same clock speed. : >In short, on paper at least, the HC16 looks like the best choice for : >most current products. So, beware the men from marketing... If you guys are using C, beware of tools that was 'migrated' from HC11 world; they generally do not handle the memory model properly. HC16 uses segmented architecture, with each segment of 64K. However, the HC16 architects are smarter than those Intel folks in that the segment (or bank) portion of the 20-bit address is automatically adjusted when crossing segments. So, no messy code to adjust segments when indexing. In fact, more than 64K can be addressed. Some tools simply forget this feature , one example is Whitesmith C, which linker does not handle segment location automatically, you have to do it manual! : > Will Wray : Depends on what you're trying to do.....I have used the 68340, 302, and : now the 360. I need to have much more processing capabilites than the HC16 : allows. Like the use of a commerically available real-time OS. and other : options. Therefore the HC16 is NOT the better choice....it obviously depends : upon the application. Depending on how you configure and what the application needs, HC3xx is not necessarily faster; remember that HC3xx are CPU32 based (32-bit) that fetch information off a 16-bit physical bus, more bus cycles involved. HC16 can mostly execute off a single bus fetch. On the point of RTOS support, there is no limitation; at least Embedded System (Used to be A.T.Barette) has RTXC and Nucleus has Nucleus Plus. If you use Introl C compiler, it comes with a kernel. BTW, both the above RTOS are targeted on HC3xx as well. : Matt ============== cut here ================= In article <1994Oct25.140437.24662@pat.uwe.ac.uk> wj-wray@uwe.ac.uk (WJ Wray) writes: >Motorolas marketing pushes the 683** series as the top of the range >microcontrollers while the 68HC16 is an upgrade path for 68HC11 users. The HC16 is source code compatible with the HC11, providing a growth path for existing HC11 applications that are running out of steam. However the 6833X incorporates a 68020 core, therefore making it source code compatible with the higher performance 68K family. This is important because more robust tools such as highly optimizing compilers are available for the 68K. I read that the 6833X should achieve approx. 2.5 MIPS and the HC16 approx. 2 MIPS. I have designed with them both, and believe the each have a place in the market. ============== cut here ================= >Chris Lucas (chris@atlanta.com) wrote: >: In article <1994Oct25.140437.24662@pat.uwe.ac.uk> wj-wray@uwe.ac.uk (WJ Wray) writes: >: >Motorolas marketing pushes the 683** series as the top of the range >: >microcontrollers while the 68HC16 is an upgrade path for 68HC11 users. >: The HC16 is source code compatible with the HC11, providing a growth >: path for existing HC11 applications that are running out of steam. >Not quite true. HC16 asm is not quite a superset of HC11. The hc16 is source code compatible with the hc11. However, the HC16 is a completly new beast. An HC16 is virtually a 6833X with a different core. The integration on an HC16(SIM, ADC, TPU, GPT, QSM) is exactly the same as that found on the beefier 6833X. These modules connect to the core via the Inter-Module Bus(IMB). The 6833X utilizes the core from the 68020, CPU32. On the other hand, the core on the HC16(CPU16) had to be redesigned to be source code compatible with the HC11. What I mean by souce code compatible is the HC16's instruction set contains as a subset, the HC11's instruction set. Chris ============== cut here ================= My thoughts: Someone (Coactive?) is working on a gcc port for the HC16. When that's out it may not be a bad choice; that's assuming you do not want to spend money on a development system and software. The CPU32's, being based on the m68k family, can already use gcc which would make it more desirable to me. Now the question is cost and availability... 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 owner-diy_efi Wed Nov 2 15:39:35 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12906; Wed, 2 Nov 94 15:39:35 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA12901; Wed, 2 Nov 94 10:39:29 -0500 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #12) id m0r2hVC-000vKRC; Wed, 2 Nov 94 09:21 CST Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #10) id m0r2hTT-000uGoC; Wed, 2 Nov 94 09:19 CST Message-Id: Received: by bangate.compaq.com with VINES ; Wed, 2 Nov 94 09:19:39 CST Date: Wed, 2 Nov 94 09:03:16 CST From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: re: Re: The files... To: diy_efi Cc: Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI John S Gwynne Wrote: | Large? Just wait till version 1.0 comes out next month :). The ps | file is indeed a schematic, but not a complete controller yet. The | file prints five pages that, when taped together, yield a D-sized | drawing of the CPU portion of what will be a controller. For more Chop off the top and right edges at the cross-hairs, and this will be much easier to tape together. | experience. I have chosen to work with the 68000 since it is the | cheapest entry into the m68k family that opens the door to a great | deal of GNU software (gcc, gas, binary utilities, glibc, gdb,...) and | the RTEMS kernel. I encourage others to work with the CPU of their | choice, and hopefully we can all share information on interfacing | and control algorithms. Speaking of RTEMS, how big is it? I know you posted this before, but where is it available? If I ever get my linux machine back up and running, I'd like to set these tools up myself.... --steve From owner-diy_efi Wed Nov 2 19:18:24 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA14503; Wed, 2 Nov 94 19:18:24 GMT Received: from smtp.utexas.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA14498; Wed, 2 Nov 94 14:18:21 -0500 Received: from mail.utexas.edu (mail.utexas.edu [128.83.126.1]) by smtp.utexas.edu (8.6.7/8.6.6) with ESMTP id NAA29791 for ; Wed, 2 Nov 1994 13:10:33 -0600 From: BigBrother@MAIL.UTEXAS.EDU Received: from [128.83.111.36] (slip-16-4.ots.utexas.edu [128.83.111.36]) by mail.utexas.edu (8.6.7/8.6.6) with SMTP id NAA03598 for ; Wed, 2 Nov 1994 13:09:10 -0600 Message-Id: <199411021909.NAA03598@mail.utexas.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 2 Nov 1994 13:09:36 -0600 To: DIY_EFI Subject: Fuel Injected Lawn Mower Engine... Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Bill, Yeah, I bet that alternator heats up pretty quick sinking 3500+ watts. > I have successfully run the ignition from a magnetic TDC reference sensor. Hmm. That TDC sensor is still firing the ignition twice per complete cycle. The crank, therefore the flywheel, is spinning twice as fast as the cam so this means the spark plug is being fired right before top dead center (compression stroke) and right before top dead center (exhaust stroke). Oh well I guess there's nothing wrong with that.. Are you running the ignition from a microcontroller that measures the TDC frequency and advances/retards timing against some kind of load reference? I'm still working on that. My initial setup is only going to have a bastard guess for load... Throttle Postion + RPM! Later, I'll upgrade to a Barrometeric Pressure sensor. Upgrading to MAF is not really needed. Plus to do it you need to block off 7/8 of a meter with something and recalibrate it! > Anyway, exactly what injector have you found that is small enough to work > on these small displacement engines. I have not found an injector that would be properly matched to the small engine, but I'm going to use a stock injector from a 5L Mustang. Not because its best suited to the engine, because I can get them free! However, I will try to get away with running it at 30 - 35 psi. I still need to conduct some tests and find out just how short of a pulse I can get out of the injector. I have a feeling it will be short enough. Anyway, we can get away with running pretty rich at idle, although I'm sure there is a limit before it effects throttle response. Another thing you need to consider is a fuel pump and pressure regulator. For this application, we really could use a small fuel pump, but I don't know of a small pump! I'll be using a (major overkill) 88 L/hr Mustang fuel pump mounted into a good old 1 gallon gas can. Yeah, it will cycle the entire can every 3 minutes, but again, its free. It looks like I will have to break down and buy an adjustable pressure regulator (or take the one off my car). We absolutely have to adjust the pressure down for the little engine. Of course, if I can get a real short pulse out of the injector, then a stock regulator will do. I'm not sure how far other people are going to go with the fuel injected Briggs & Stratons, etc. I'm just messing with them so I get a grip on fuel injection: microcontrollers, sensors, and actuators before I go on to something more important- like a car engine, etc. From owner-diy_efi Wed Nov 2 22:38:26 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA19463; Wed, 2 Nov 94 22:38:26 GMT Received: from us.dynix.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA19458; Wed, 2 Nov 94 17:38:23 -0500 Received: from cpu.us.dynix.com by dnxjcit.us.dynix.com with SMTP id AA02793 (5.65c/IDA-1.4.4 for ); Wed, 2 Nov 1994 15:42:35 -0700 Received: by cpu.us.dynix.com (AIX 3.2/UCB 5.64/4.03) id AA83964; Wed, 2 Nov 1994 15:35:31 -0700 Date: Wed, 2 Nov 1994 15:32:43 -700 (MST) From: Jim Conforti Subject: Mustang mass air flow sensors To: DIY_EFI Cc: hotrod@dsea.com Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Does anyone know anything about the Hitachi air mass sensors used on some of the mustangs .. They have an analog voltage (v. PWM) output to the ECU .. Any info/specs greatly appreciated I'm going to interface this sensor to the Bosch Motronic system Jim Conforti From owner-diy_efi Wed Nov 2 22:54:19 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA19505; Wed, 2 Nov 94 22:54:19 GMT Received: from smtp.utexas.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA19500; Wed, 2 Nov 94 17:54:15 -0500 Received: from mail.utexas.edu (mail.utexas.edu [128.83.126.1]) by smtp.utexas.edu (8.6.7/8.6.6) with ESMTP id QAA09542 for ; Wed, 2 Nov 1994 16:49:27 -0600 From: BigBrother@mail.utexas.edu Received: from [128.83.111.140] (slip-19-12.ots.utexas.edu [128.83.111.140]) by mail.utexas.edu (8.6.7/8.6.6) with SMTP id QAA27865 for ; Wed, 2 Nov 1994 16:48:08 -0600 Message-Id: <199411022248.QAA27865@mail.utexas.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 2 Nov 1994 16:48:34 -0600 To: DIY_EFI Subject: SERIOUS powerPC microcontrollers are born Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI I read this addition to the comp.sys.m68k FAQ, and thought I'd pass it along..... In article , boys@fis.utoronto.ca writes: H) PowerPC Embedded Controllers -------------------------------- The IBM PPC403GA is a 32 bit processor rumoured to deliver 72k Dhrystones per second @ 33 Mhz. It has a DMA, DRAM and I/O controllers, two-way associative instruction and data caches, serial port and multiple timer facilities. It runs at 3.3 volts and interfaces with both 3.3 and 5 volt peripheral parts. It comes in a 160 pin PQFP package and is priced at $49 @ 25 Mhz for 1000 pieces. It is being sampled now with volume production expected by the end of 1994 and 33 Mhz version is expected in early 1995. The Motorola MPC505 has a floating point unit, 4 kbytes static ram, 4 Kbytes instruction cache, 32 bit RISC processor, 32 x 32 bits general purpose register file and 32 x 64 bits FP register file. There are chip selects, a watchdog timer and various I/O ports. It comes in a 160 pin QFP package @25 Mhz and with a clock speed of 25 Mhz and uses a 3.3 volt power supply. It will be sampled in November 1994 and is initially priced at $75 for small quantities. A 144 pin package will be offered later. Volume pricing is expected to be $55 by 1995 and down to $25 by 1997. From owner-diy_efi Wed Nov 2 23:31:42 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA19573; Wed, 2 Nov 94 23:31:42 GMT Received: from access3.digex.net by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/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 AA19568; Wed, 2 Nov 94 18:31:35 -0500 Received: by access3.digex.net id AA29173 (5.67b8/IDA-1.5 for DIY_EFI@coulomb.eng.ohio-state.edu); Wed, 2 Nov 1994 18:31:25 -0500 From: Andy Harrah Message-Id: <199411022331.AA29173@access3.digex.net> Subject: Fuel injected lawn mower To: DIY_EFI Date: Wed, 2 Nov 1994 18:31:24 -0500 (EST) X-Mailer: ELM [version 2.4 PL24beta] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 4685 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Jeff, > Yeah, I bet that alternator heats up pretty quick sinking 3500+ watts. I've never run with much of a load, so it doesn't 'over' heat. I did have it connected to an old worn out 3 hp Briggs from my garden tiller. At a fast idle, if you crank the load up on the 'brake' it drags that motor to a stop almost instantly. Applying a load to a motor under test I find is a huge problem. Having the rest of a car hanging off the crankshaft provides a great load but its a pain to drive and fiddle with a keyboard at the same time. Doing it on the little engines seems like an easier place to learn. I've imagined all sorts of schemes to build a dyno for a lawn mower sized engine. None is as easily controled as the alternator. All four-stroke cycle lawn mower engines and almost all four-stroke motorcycle engine fire every revolution. All the newer distributor-less microprocessor controlled car ignitions do as well. That extra spark just flaps in the breeze. You'll notice these ignition systems use blocks of coils with twin outputs. They connect the pairs to cylinders that appear one full revolution apart in the firing order. One is actually firing, and the other is wasted. My system takes interrupts off the TDC reference and calculates the RPM. Based on the RPM, it looks up the advance from a centrigual advance type table. This value is then used to predict when to fire the next time, in advance of actually receiving the TDC reference pulse. The reference pulse actually is set to about 6 degrees BTDC so that it can be used to fire the coil directly. This is used before the micro is up to speed, or if it crashes. Currently there is no load input to calculations. The TTL level output of the micro drives the ignition coil through a VW Rabbit amplifier module. By the way, that scheme of one pulse per revolution isn't accurate on any engine that can rev very quickly. I read somewhere that Ford had trouble with the controllers for the Taurus SHO because that motor can rev at 20000 rpm / second which was too fast for their systems to keep up with. I guess that's why all the Motronic systems take pulses off the flywheel ring gears as well as a TDC reference pulse. A few years ago I played around with the same thing on a Chevy 350. On that one I used a manifold pressure sensor. Before I had my gadget working, I hooked it up to the stock system. I drove around and collected the factory timing curves, RPM and manifold pressure. I copied that data into my system as-is. It was built around an NEC V40 which is kind of like an Intel 80188 with a different set of on-chip peripherals. I had an 8K static RAM, an 8K EPROM, an 8-input ADC, 8 bits of dip switch input and 8 LEDs for output. My current work is with a 68HC11. I'm using this table driven assembler called TASM which is kind of shareware. For $40 the guy sent me the source code. I converted it to work as a Windows app. ( Windowless, just takes a command line) I'm using Visual Basic to draw control panels with meters, etc. The 'HC11 uploads data to the laptop over the serial line. I'm hoping it'll prove to be a nice setup. I have a bunch of Chevy 305 and 350 injectors that I got for free, too. I don't think they'll work on the Briggs. The per cylinder displacement of the V8 is about 625 cc. The Tecumseh engines I've got range from about 125 to 200 cc. Late model VW Bugs had L-Jetronic injection. Those motors are 400 cc per cyl. There must be some tiny motor in some imports that would match closer. I'm very worried that the dynamic range of the injectors will be a problem. Perhaps running a lower fuel pressure would help, but that might foul up the spray pattern. I believe the minimum pulse length for the injectors is about 1 to 2 ms. There are also considerations on the electrical drive for the injector. They come in different forms. Some are designed to be used with an external current limiting resistor, and some are supposed to be connected to more intelligent drive electronics that watches the current ramp until the inductance saturates and then back the current down to a 'hold' level. There are some decent discussions of this in that blue Bosch injection book. Also, the Motorola and National Semiconductor linear databooks describe chips to control injectors. Not that we can get them, but they talk about how they work. I'm planning on using a VW CIS fuel pump, just because that's what I can get. I'm not sure what I'll do about the regulator. I've got a lathe, and I'm reasonably handy with it. I might try to make one. I've got a VW Corrado VR6. Someday I'd like to fiddle with the programming in that beast. .../Bill