Chainsaw Repair

Cool stuff.  Looks like temp, MAS or a TPS, and rpm is monitored. Might be a few creative ways to "fool" the processor if the cylinder head temp Sensor plays a significant role in fuel flow. 

Future of saw Emissions/Fuel Controls?

Takes between 2 to 3 years from the time a patent application idea is filed to be granted a patent in the USA.
However, not all patents granted are actually used in future production.  Using this timetable, the following
could be a hint of what is coming down the pike.


2014 patent applications (+/- 2017 production?):

Echo (Yamabiko):  Electric (solenoid) controlled main jet passage.
Stihl:  Multi-ECU controlled carb/ignition engine management.
Split intake tract.
Tamper-proof deeply recessed mix-adjusting needle design.
Husqvarna: Exhaust Lamda sensor.  (O2 sensor).


2013 patent applications (+/- 2016 production?):

Husqvarna:  Method of adding extra fuel (carburetor), for engine start-up.
Stihl:  Crankcase Lamda sensor.  (O2 sensor).
Device to permit optimum ignition timing in partial load (mid throttle) positions.
Fuel pressure regulator for fuel injected application.
Multi sensor ignition coil high voltage control.
Dolmar:  Combustion chamber, Lamda sensor.  (O2 sensor).


2012 patent applications (+/- 2015 production?):

Husqvarna:  Direct injection system.
Inlet tract improvement device to prevent backflow from crankcase into inlet tract.
Stihl:  Piston recess connectect to intake tract for intake fuel mix control.
Device for alternating ignition angle before tdc used for RPM control.


2011 patent applications (+/- 2014 production?):

Stihl:  Low pressure fuel injection control method/device.


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Note:  This list does not include patent information from Zama and Walbro.

I love the idea of all this tech making its way into saws but the reality of it all is that it is going to complicate diagnoses and add a lot of cost to repairing saws. pushing us eventually more and more towards the throw away society

Cool stuff.  Looks like temp, MAS or a TPS, and rpm is monitored. Might be a few creative ways to "fool" the processor if the cylinder head temp Sensor plays a significant role in fuel flow.

if it turns out to be a CHTsensor, possibly an insulating washer under the plug??

Looks like a washer under the plug in the patent drawing.  Seems a little funky and slow reading?