IC Ignitor WIP

Bummer. Slipped with the tweezers and it flew across the room? BTDT.

Just keep telling yourself that in the grand scheme of things, it was an academic study.

 

Chacal,

I haven't seen any of the replacement units with my own two eyes, but I assume they are functionally equivalent from a "black box" perspective. In other words... They operate like the original one does, but there's no confines as to HOW they accomplish the task. Inside the box, the entire concept is probably completely different than the stock unit, but when viewed as an assembly from outside the box (black box), it appears to operate the same as the original.

I assume all the aftermarket units use a little microcontroller and do the advance and dwell controls with software, while the original one did it with stone knives and bearskins (capacitors, oscillators, comparators, etc).

The original was analog, while the new ones are probably digital. An offshoot of Moore's Law.

 

Rice, you are probably correct, but how is/are those dwell and advance curves determined by the software programmers (unless they had access to proprietary data?). The published advance curves in the shop manuals seems to have far too wide of a range to be acceptable for use in a modern (or even a stone knives) environment.........

 

Well I'm no ignition expert, but if the graph in the FSM is the ONLY piece of info at my disposal, I would just aim for the center of the range at a couple points and naively hope for the best. Put it on a dyno and hope I don't hole a piston? My experience with old Japanese documentation is that barring typos, it's usually pretty accurate.

Other ideas?

I would run a reality check on the numbers and do a little research to see if they were at least "reasonable". For example, according to the timing curve from the SECA 550 FSM:

Does it make sense that the advance is flat at 5 degrees advance up to 1200 RPM.
And from there, the advance increases to 7 degrees at 1850 RPM and ramps from there to 36 degrees at 3300 RPM.
And according to the graph, the timing is all in at 38 degrees by 4000 RPM.

I would try to find myself someone who knew a lot about ignition and try to find out... Does all that seem at least reasonable? Does that all sound reasonable for a 550 cc four cylinder engine with a redline of 10K?

I would test one of the factory units and characterize how it performed. Simulating the engine rotation, I have already run the stock unit up and down in RPM on the bench, and measured the advance at a couple points. But my setup was crude and not particularly accurate. I'd be happy to do a more thorough job, but I need a nice digital storage scope. My old analog scope just isn't up to the task.

You could measure the advance amounts with the engine running on a real bike as well. Noisier and hotter than doing it on the bench, but certainly an option.

I would research around a little and see if I heard reports of people blowing up their engines from detonation or ignition timing too advanced. I've been (mostly lurking) around here for a couple years and I don't think I've ever seen or heard about anyone holing a piston or grenading their engine from a detonation issue, so I think we're good there.

I would also try to line up test mules and if I was planning to sell such devices, I would rent some dyno time. Not only could this be used for marketing fodder, but with the aid of a rectal O2 sensor and temp sensors on the exhaust pipes, they might also be able to determine how well the ignition was performing. Maybe.

 

No, you're no expert......! But you do know more than most of them.

 

Which way to the motorcycle forum? You guys are so over my head, it's like you're speaking a different language! Xrays, microscopes, chips flying around, this is the sci-fi channel!

 

What you're saying makes a lot of sense to me and I think your methodology is about the best way to go about it. But what do I know, I'm just a wrench turner.

 

this was to easy is this the part?
http://www.ic2ic.com/search.jsp?sSearchWord=HA1825P&prefix=H

or this
https://www.jotrin.com/product/parts/HA1825P

 

I had seen them for sale, but it is still difficult to tell if they are an exact match. The package (number of pins) might even be doubtful. And, the real interest is to determine what the part is, and not only is there not a valid link to a datasheet on those sites, but they don't even offer up a description of the part. I tried creating an account, but still no datasheet available. Looks like the account is mainly for purchasing the part.

 

thats why i thought it was to easy.

 

Correct, and reminding myself of that was the only way to stop the tears.

Yeah, just a question of if it is the same thing without any spec sheets. on the plus side, I have a reasonable idea now of what is on the inside, so I could at least decap one and give a preliminary report on how it appears to stack up.

 

I replaced mine with a B&G Microsquirt. I'm still using a stock pickup, but with a custom crank wheel. Nothing else between that pickup and the spark plugs is original, though.

However, since devices like the Microsquirt can be triggered by a stock crank pickup, I'm quite confident that the ignition logic, drivers, VR conditioner, etc, are all available that could be used to replace just a TCI as well (I'm doing fuel and ignition with the MS). The MS2Extra software is open source. The Microsquirt designs are also open source, and they have modules for some of them, if you don't want the whole assembly.

FWIW, I did replace the on-board VR conditioner in my Microsquirt with an NCV1124. That solved some high RPM problems that I think B&G finally fixed in a different way for themselves. Mine was one of the first batch of Microsquirts made, so there were some teething pains... Microsquirt uses VB921 drivers... at least mine does. I think these are NLA and have been replaced by BIP373. Probably the cheapest option would be if someone added an NCV1124, a pair of BIP373s, and a 7805 to one of these CHIP boards (https://getchip.com/pages/chip) and ported over the crank wheel and ignition logic from MS2Extra. Or maybe even use a Cypress PSOC as the MCU. Pretty sure those are still faster than the 68HC11 used in the Microsquirt.

Net net is that the single trigger that's used by the TCI should be OK to trigger a TCI replacement as well. My first design used a single tooth trigger. More teeth will allow the system to synch faster, (less cranking before the system knows what the engine speed is) and will allow better timing accuracy when engine speed is changing.

 

Haha! You give me way too much credit, my friend!

 

Macktion, Seriously... Been there, done that. Just the other day I was doing some very small electronics work, holding a part with the tweezers, and "snik" it was gone. I have no idea if it landed two feet away or twenty feet away. Looked a little bit and never found it.

So you're right. At least now we know what the die looks like, so if someone wants to try to buy some of those HA1825's and send you one... You can at least tell if they're legit!

 

SQLGuy, Sounds like a neat project. I know there are a couple aftermarket options out there like the microsquirt and jolt something.

I don't really know what I'm looking at, but back when Yu Tanaka did his first Tesla version, I took a quick look at the code, and it appeared that he was breaking up the RPM range into 500 RPM chunks (for example from 2000 to 2500) and using the range to adjust the timing conditions. At least that's how it appeared to me. Sort of quantizing the operating range into blocks to make the math easier?

Do you know if your system do something like that, or is it a continuous sliding calculation throughout the entire range? With a powerful enough processor, you could do more math.

 

It's based on tables that are usually 12x12 of RPM versus engine load, but it does interpolate intermediate values as well based on exact measurements. So, if you're at 1500 RPM, and your table points are 1200 and 2000, it will calculate an intermediate advance value. Factors like inlet air temperature can also be used to adjust advance.

A really simple version, though, could be done with a flat 12 bin table with no other factors feeding in... just advance based on RPM.

 

Gotcha. I believe you're talking about piecewise linearization (piecewise linear interpolation).

And now that I think about it, it's completely conceivable that the code I was looking at did that. I didn't really know what I was looking at in the first place, and didn't spend a lot of time trying to figure out exactly what was going on.

In any event, you can do that with just a small amount of processing power.

 

All modern microcontrollers have way more than enough power to do even full fuel and air with sequential injection, etc. Microsquirt has a 16-bit 24MHz CPU. The MPU in the Cypress PSoC 5 device I'm using for a completely different project right now is an 80Mhz 32-bit ARM device. And the development tools are really easy to work with. You can even do all sorts of modular digital and analog stuff on-chip, without CPU involvement.

 

You two need to get a private room together..............!

 

Chacal, is there a need/market for a TCI replacement? Something with adjustable timing tables and dwell? If so, what price point would it need to hit to be compelling?