The VeeCU

[WesRagle]

HI Guys,

Back from the park and working on injection pulses.

Here is a shot of three of the injector pulses. One pulse has zero delay and 10 micro second duration. The second has 10 micro seconds of delay and 20 micro seconds of duration. The third has 30 micro seconds of delay and 30 micro seconds of duration. The forth was too hard to get to :-)



The delay and duration are controllable in 10 micro second increments up to (delay + duration) = 65535. Setting the timer to 10 micro second increments allows 0.65535 seconds as the maximum pulse width. I can't imagine every needing more than that. And, 10 micro second resolution on injector pulse width seems more than adequate. It makes for simple code so I'm calling that good enough.

It's time for what new grads call re-factoring. It's what we used to call clean up. I'll start a new project in the development environment and bring the code over piece by piece improving/simplifying where ever possible.

Looking to the future, I've implemented the 3-D lookup routine for typical VE lookup. Not sure that is the way I'll go but I'm ready if that's what I decide. It's interesting to see all the hoops folks jump through trying to get a good start (Ref.https://www.hptuners.com/help/vcm_editor_parameters_gm_eng_fuel_general.htm). We'll see how that goes :-)

It's time to start considering signal conditioning. Can I really replace my ignition coils with optical couplers?? Hum....

EDIT: So, I couldn't resist. I went to the shop and replaced one of the ignition coils with a 10K just for a test. When the DYNA-S fired the low end of the resistor went to 0.5 volts and then back all the way to bus voltage while "charging". The DYNA-S hung in all the way to below 5 Volts at which point it just turned on (0.4 volts). So, looks like appropriately sized resistors and opto-couplers is a viable option for acquiring the secondary ignition pulse.

Forever Forward,

Wes

[sonex1566]

Hi Wes,
While you, Peter and a couple of others are chasing the perfectly smooth running engine down the electronic rabbit hole....I've gone down the opposite path using steam power instead. I'm almost finished machining up my own custom slide needle with two difference angles to cope with the different fuel demands of idle and high power settings. If nothing else it would make a good conversation to have over a beer whilst we work out who is crazier!. Good luck.

[WesRagle]

HI Richard,

"Crazier" is right. Anyone who builds an airplane in the garage/shop is certifiable to begin with.

That looks like a fun experiment. Me, I took the "Red Pill" and I'm way down the rabbit hole. If you're able to balance fuel to the individual cylinders with that needle I'll be out in a heart beat and begging for a copy ;-)

Wes

[WesRagle]

Hi Guys,

I'm down a rabbit hole in a rabbit hole. I going to attempt to "glue" four boards together to form the "Proof of Concept" unit for what will eventually be the VeeCU. In order to do that I need signal conditioning circuitry. So ..., full speed ahead and damn the torpedoes. I've been trying to figure out how those folks I used to work with laid out PCBs.

I just sent off for my first attempt. What comes back may make for a good laugh. It costs about $60 total for a small two sided board (minimum qty. 5). BTW, the real deal will be laid out by a professional.



If there are any PCB designers and or EEs on the list, I would love your contact information so I could ask some questions :-)

Now, back to the display board.

Forever Forward

Wes

[sonex1566]

Hi Wes,
I believe that there must be something wrong with me, but I was thinking about your problems today whilst stuck in traffic on my way to work this morning. Peter Henry put up his picture of his fuel manifold on the top of his injectors fitted to his inlet manifold and wondered how you were going to go fitting it inside your cowling. However, last year I wasted far too much time getting a mate's Ducati Monster going after it had been sitting for years. But what I was thinking about was how Ducati got around supplying fuel to their injectors on their V-twin engine. They just used a banjo bolt in the top of each injector and used flexible fuel tubing to go from the pump and then from one injector to the other and then the fuel pressure regulator was tacked on the end where the unused fuel was returned directly back to the tank. I was wondering if that would be a simpler and more compact way of supplying fuel to your injectors. I'll take the management role here and supervise you while you scratch your head and wonder how the hell you actually plumb it all together!

[WesRagle]

Hi Richard,

In the end analysis, I'll have to keep the height of the injectors to a minimum. I don't think there will be a way on the Onex to keep them inside the stock cowl. I can probably figure out the plumbing, execution may be a problem :-) I like the simplicity of Peter's setup/plumbing. Ref: https://sonexbuilders.net/viewtopic.php?f=66&t=6131&start=30#p46432

The worry is heating up the fuel while pumping without the engine running. Peter is using a lower power fuel pump than the Walbro which will mitigate the fuel heating problem. I just received one of the 45 L/Hr to use for initial testing.

Ref. https://www.aliexpress.com/item/32380160597.html?spm=a2g0o.productlist.0.0.32871f56sbQfsA&algo_pvid=4be4927d-f1cd-40a4-bda1-f182f03d1219&algo_expid=4be4927d-f1cd-40a4-bda1-f182f03d1219-0&btsid=0b0a555c16214710569158615ea0a0&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

The lowest profile injectors I have seen are the ones suggested in Jeff's post.

Ref: https://sonexbuilders.net/viewtopic.php?f=66&t=6131&start=20#p46384

Or maybe these I just stumbled across. These make an attempt to spec the on/off times and are apparently sold with mating connectors.

Ref: https://www.aliexpress.com/item/32292413156.html?spm=a2g0o.detail.0.0.5b775719T2SjLE&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=eacc2810-3a5d-4133-8a8e-3d52f0784781&_t=gps-id:pcDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:eacc2810-3a5d-4133-8a8e-3d52f0784781,tpp_buckets:668%230%23131923%230_668%230%23131923%230_668%23888%233325%2316_668%23888%233325%2316_668%232846%238109%231935_668%235811%2327179%2339_668%232717%237560%23252_668%231000022185%231000066059%230_668%233468%2315615%23642_668%232846%238109%231935_668%235811%2327179%2339_668%232717%237560%23252_668%233164%239976%23803_668%233468%2315615%23642

Bottom line, left to my own devices I'll use the lower power pump and the one of the low profile injectors mentioned above. If I go with the 45 L/Hr pump for flight, I'll probably run redundant pumps for takeoff/landing.

Anyway, I'll probably have to modify the cowling no matter what. But ..., I can't look at all of the problems at once or I'll vapor lock. Right now I just need to get a system together and go for an engine start. An engine start would be very motivating :-)

Just gotta keep plugging at it.

Wes

[imamac96]

Wes, have you ever thought of buying a 3018 or similar? Like this: (https://www.amazon.com/Genmitsu-3018-PR ... B07P6K9BL3). It's a small, cheap CNC router that a lot of people use for one-off boards. I think it's an open-source design so there are a bajillion clones sold everywhere. You really shouldn't do it in industry, but for you it might be good to have. Of course, the learning curve for CNC absolutely blows. My philosophy is that I don't factor tools into cost because they hold some resale value if I decide I don't want them anymore.

Cheers,
Connor

[WesRagle]

HI Connor,

I have never heard of that before. Looks pretty cool. But, I don't really want to go off on another learning curve right now. I'm kinda learned out at the moment. It took much longer than I expected just to layout a simple two layer through hole board. First I had to evaluate several "free" design tools. And it's hard to evaluate a tool which assists with a task you have never done before:-) Turns out that for a beginner probably the most important consideration is the tools ability to import available models/footprints so you can skip the "Parts Builder" part of the learning curve.

Wes

[WesRagle]

Hi Guys,

Quick update on the VeeCU project. Moving along at a glacial pace.

I received my PCB. We'll call it PCBs for preschoolers. There was only one trace missing :-) I assembled it and it passed a static check on the bench. Next I'll have to hook up the sensors to the engine and see them work with the engine running.

Here is a pic of some of the bits and pieces that have been collected so far:



I'm going to copy Peter Henry's fuel distribution scheme. During testing the fuel sump will be replaced with a temperature sensor so I can see how quickly (or not) the fuel pump heats up the fuel.

After a rather lengthy search I found the mating connector for the fuel injector and an affordable crimp tool here:

http://www.cycleterminal.com/index.html

I couldn't very well start soldering and such on my Wife's built-ins so I had to clean out a space in the shop. The office has never been used as an office. It turned into a place where discarded items go to die. So, I had to clean it up and give it a fresh coat of paint. Amazingly enough the air conditioner still works.



I don't want to have to worry every time I fire up the test engine so I installed concrete anchors and bolted the Sonerai to the shop floor.




I need a portal into the ECU during development. So, I took time out to get the CAN interface and display up on what will serve as the control head during development. The CAN peripheral has been updated to support CAN FD (which I don't need or want) so it took much longer than I thought it would since I had to learn how to make the new peripheral support "Classic Can".



I can page through any number of displays with the blue button.

I'm going to retrieve my build table from Olney, set it up next to the Sonerai, and build an instrument panel on it. I'll extend the engine controls and sensor signals so I can watch everything without poking my head into the cockpit. I'm going to mount the fuel system to the table as well. I'll run both the low pressure and high pressure fuel sources from the table to the Sonerai.

The engine hasn't been run in about two years. The left front cylinder exhaust valve is leaking badly. But, I'm not going to worry about that just yet. I'll just change the oil, torque the prop, and see if I can get an engine start running on the carb. That will allow me to hook up sensors and scope the inputs and outputs of the input signal conditioning circuitry and see how well that works.

Forever Forward,

Wes

[WesRagle]

Hi Guys,

OK, trouble in paradise.

I took the stubby pipes off the Sonerai and did a test fit of the second hand Sonex pipes I bought.



I should have known it wouldn't be that easy :-)

I took the pipes, the O2 sensor, and the sensor bungs to the exhaust shop this morning and learned (re-learned) that most shops don't have the capability of working with 1 3/8" pipe, regardless of the material.

I may have to build a stainless deflector, mount it forward of the firewall, and leave the extensions off but that would put the O2 sensor too close to the exhaust port (24" minimum recommended).

So, this is a problem in search of a solution ... Wishing I had an engine test stand.

Wes