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That is informative. Thanks.
I find it interesting
https://ac.els-cdn.com/S187661021733...c98cd1376f3d10
this is where I got to with the Ecotrons 2S EFI system.
People have asked what am I doing and I find it easier to explain that I had written a story using a foreign language (Ecotrons) and to change the ending of the story I need to use a different language ( Speeduino). But to change the ending I first have to re write the story in the new language so it reads the same as it did in the old one. When I have done that then I can change the ending to a more interesting one.
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I spent a very happy peaceful Christmas day in the shed. Slowly working through the typical issues you get with a new project.
I have traced the heart stopping engine flame outs to a faulty 12V power plug and have now soldered the 12V supply directly to the Arduino Mega board. And another issue causing flame outs and the motor stopping dead was the Mega board becoming detached from the Speedy board. On over run the vibration is sever enough to shake the board loose. Given how tight they are on the pins it was a bit of a surprise.
Having fixed that, I am now on the hunt for why the TPS signal appears so noisy on over run. The new analog smoothing option in Tuning Studio that comes with the latest Speedy firmware upgrade should be useful for sorting out if it is a mechanical or electrical issue.
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Noisy TPS on overrun is probably the same cause as the Mega board becoming detached. I wonder if the TPS was as noisy with the Ecotrons system. I'd be looking at loose connections, or maybe the position sensor simply has a hard time with excess vibration due to the spring loade wiper being bounced about.
There might be something in that.
I had a look back at earlier traces before I secured the Mega board and there does not seem to be the same TPS noise. How that can be, I have no idea. It is hard to imagine anything on the board itself that could be affected by vibration.
Or maybe it is coincidental and like you say, the issue is something has started bouncing around in the TPS itself too now.
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The Steps for down loading and installing the Speeduino EFI software:-
From The Main Speeduino Home Screen.
Step 1. Download Firmware.
Step 2 Download Latest Stable Firmware.
Step 3. Unpack Zip File.
Step 4. Speeduino-INI setup file for Tuning Studio is in the Reference Directory.
Step 5. Speeduino-INI file to be loaded into Tuning Studio. This file is the Bridge between Tuning Studio and Speeduino.
Step 6. Speeduino Firmware code is in the Speeduino Directory.
Step 7. Compile and Upload Speeduino Firmware to the Arduino Mega board.
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Step 6. Speeduino Firmware code is in the Speeduino Directory.
Step 7. Compile and Upload Speeduino Firmware to the Arduino Mega board.
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I have finally got back to a point where the engine is running well enough for me to start looking at the "Two Stroke MAP" concept again. I am only working in the low throttle low RPM area but it is probably the most demanding if you are looking for differences in air flow between firing and misfiring.
Because that is the region where a two stroke can be four, six, eight or more stroking. Ie misfiring but not from poor spark but bad air fuel ratio in the cylinder caused by random mixing of the old burnt exhaust gas that has found its way back to the crankcase with the small amount of fresh air coming in at low throttle openings.
At low speed/throttle the crankcase has a high proportion of exhaust gas in it and it is not always certain that what fresh mixture that there is at low speed finds its way to the cylinder each cycle.
The average crankcase pressure at idle and low speed/rpm is close to atmospheric because of back flow from the exhaust. Idle air/fuel mixture is the small amount of fresh air that makes its way through this fog. A small amount of fresh air in equals the same volume but random ratio of dirty plus fresh air/fuel mixture out and up to the cylinder.
This randomness of how much incoming air/fuel actually makes it to the cylinder is another reason a four stroke style MAF sensor on the inlet side makes no sense for a two stroke. You would actually have to measure the flow and oxygen content going up the transfers to have a meaningful MAF style measurement.
At low demand it is rather random the ratio of dirty exhaust gas in the crankcase to combustible air/fuel mixture that finds its way to the cylinder on the next cycle. This randomness is the reason for the corn popping ring ding two stroke sound.
Husaberg posted a very interesting link.
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Well I got to play tonight with the 2S-Map software and coded up a simple Max - Min and smoothed pseudo MAP value. I scraped an exponential smoothing logarithm off the net .... yn = w × xn + (1 – w) × yn – 1 ... no array and just one easy line of code.
The engine was running sort of reasonably on Alpha-N and a fixed MAP input the other day. But with the variable MAP value the motor has become troublesome on the same tune. Coincidental or somehow affected by the new MAP values, I am not sure.
Anyway the MAP does change from about 0.3bar to 1.40bar, but not very smoothly. As the motor is not running that great I can't tell how useful the pseudo MAP results are going to be.
Still it is great to have something to work with and I will know more in a few days hopefully. With any luck I will be able to get the motor running better and be able to log some data. That should tell me if I am on the right track.
It is such hard work making "reality" conform to "theory" ........... ..... https://youtu.be/Ml7dmxb8ghw
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Looks great, what does the MAP input do in the code? In Microsquirt there is a MAPxRPM table, the value in the table is a multiplier for the value in the TPSxRPM table. Or it can switch from one TPSxRPM table to another based on a threshold MAP value.
I presume you're taking the MIN and MAX per cycle in the speeduino code.
At what crank position does the cycle start (MIN and MAX values reset)?
How often does the ADC read the MAP input?
How often is MAX-MIN calculated?
Can you log the MIN and MAX separately?
Can the speeduino do fast logging at the ADC speed?
Why are you smoothing? I'd be expecting MAX-MIN to jump from extreme to extreme depending on whether there's fire or not.
Is it clear cut enough that you can switch tables based on some threshold value, say 1 bar? Can you have an output power an LED when the table is switched, so you can see the LED flashing in real time with the pipe dings?
Sorry about the questions, love your work though.
You don't work for KTM by any chance?
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