Oil injection sounds like an accident waiting to happen. I'll end up putting straight gas in the wrong saw or mix gas in the oil injected one and smoke the place out.
Whoa ... "Stihl's" new saw
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Cody
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I'm just curious, does the saw take into consideration the temperature while running? Doesn't seem like it'd be very accurate with where it's placed. If it's only for cold starts it would make sense why there can be issues with hot starts.
Yes the saw takes the temperature into consideration while running.
Zitat from the introducion of the MS 441 C-M:
By monitoring the engine temperature and speed, the control unit continually checks the operating state of the chain saw and adjusts the fuel flow so that optimal engine power is always available.
So if it starts running hot it supplies more fuel? Aside from actually injecting fuel it sounds like it's doing all the control of fuel injection.
Cody
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Just my opinion, but that's a horrible way to measure temperature. Air temp and cylinder temp would be the two temperatures I would want it measuring, and if it's inside the coil it doesn't seem like it could do that accurately. I'm sure though through their testing they found out how to make it work.
Hot would mean less fuel, less oxygen so it leans it out. Can't wait to see what there are for sensors on this fuel injected saw.
I was under the impression that if you lean it out then it runs hotter then if it's rich. Why would you make the saw hit top rpm with less oil when it's running hot. Friction creates heat.
There aren`t much sensors on it. It (TS 500i) has a combinated temp/pressure sensor and the injection valve, both placed on the crankcase. The injection system on the MS 500i will be the same in my opinion, but it will work with a higher engine speed.
Cody
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Well, that really depends on the engine. Most Harley engines like to be tuned 13.2 - 13.4:1 AFR, where as my style of sport bike 12.6-12.9:1 is preferred. It was actually proved that leaning them out a bit more on the top end provided more peak horsepower but at the risk of pre detonation so most tuners would leave them a little richer. So by all means, those engines are already running a bit richer with 14.7: being stoichometric. Anything higher than that is lean, and some automotive engines will actually run as high as 18:1 but not under load as again, that risk pre igniting the fuel in the cylinder. Forced induction engines like much richer fuel ratios as well, sometimes below 12:1. While we can't tell what our chainsaws are truly running at, seems to be the general concensus to tune to a certain rpm, or by ear. Tune it rich enough that it 4 strokes out of the cut and cleans up in the cut, but who knows what the actual AFR is. Yes, I like my saws tuned a bit richer as well. Hot air is less dense, requiring less fuel to run at the same rpm/ratio in hotter weather, but I leave my saws tuned the same all year long.
All the Mtronic saws have a regular advance built into the coil, most newer saws do. However timing does not constantly change, it simply advances above idle rpm and retards at low rpm for ease of starting. The Mtronic system looks for nothing more than the best rpm under load, too lean rpm's drop, too rich rpm's drop. That's it! This is stated in many technical documents that have been on this site numerous times. The Husqvarna system has a temp sensor and TPS sensor, it's a more advanced system than the current Mtronic saws, when running correctly I prefer the Husqvarna system, as it seems to meeter fuel more precisely IMHO.
This. MTronic is far simple than people want to make it out to be. Creative Stihl marketing in the wording convinces most that it does a lot more that it actually does.
Creative is just a slight understatement. LOL
I have been wondering where they put the altimeter to tell the carb it was operating at 5000 feet above sea level.
I have been wondering where they put the altimeter to tell the carb it was operating at 5000 feet above sea level.
They'd just use a barometer, that can be mounted right to the board, if they have one
Then they'd know the air pressure, too. But there's no 'board' per se, let alone any exterior sensors. There's a software driven micro processor inside the coil that basically samples rpm activity at a very high rate to adjust the carb solenoid accordingly based on pre-programmed algorithms. The end.
Huskybill
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Nothing like the smell of “00” buck being fired in the morning. Smells like we’re eating doves tonight. Lol
What temperature is actually being measured and what are the tolerances for accuracy? I would assume crank case temp, but so many variables play into such a measurement that I also assume it is used for historical reasons rather than real-time performance adjustments?
Huskybill
Addicted to ArboristSite
Seeing fuel injection on a chainsaw scares me. More stuff to go wrong. Sensors may carbon up with 2t mix?
I guess it’s time to put some older saws away, after making sure there good to go.
My old 55 Willy’s jeep still runs and plows snow while my 99 jeep needs a frame.
I guess it’s time to put some older saws away, after making sure there good to go.
My old 55 Willy’s jeep still runs and plows snow while my 99 jeep needs a frame.
The temp of the control unit is taken. There is no other posibility if the sensor is in there. They take this for the engine and it should be accurate enough to operate the system. Of course this is not so efective like it is on a car but it works.
I got the new Holzmachen magazine and they write that the MS 500i will be presented to the general public on the Interforst show in Munich, Germany on July 18th-22th 2018. On some markets, also Germany the 500i is already for some customers as limited version availible for the beginning of the wood making season 2018/2019 (sounds like beginning of winter). The generall release should be worldwide at the beginning of the next year. All this was in an article in the Holzmachen magazine. No warranty if that information is right or not.
Overkill338
M-Tronicly Obsessed
For anyone that wants to know, the MS462 has been pushed back from the 4th quarter of this year, until 3rd quarter of 2019.
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