3 Cycle chainsaws

[Darin]

Guess what Stihl is developing? Yep, a 3 cycle chainsaw. It has valves and runs on two cycle. This could be the development to make 2 cycle saws dinosaurs. The govenment at work (at least the one's that do work). Its not perfect yet, but knowing Stihl, it will be.

 

[HUSKYMAN]

I take it the valves in the head reduce the unburnt gas being released or something? Does this thing have a cam? sounds like a lot more weight to me. What are going to call it, the Magnum Tricycle?

 

[Darin]

I am not sure on how its built exactly. I dont know if I blew the cover on the deal, because I am friends with some high ups at stihl. They actually bought the idea from somebody. They couldnt get it too pass emissions. Stihl wouldnt have purchased it if they couldnt get it to do so. Its a couple years away he said.

 

[homelite360]

it sounds like it will be like the cadilac 4-6-8 motor of the early 80's such a bomb that they only offered it for half a year. leave it to the germans to screw everything up for us all.

 

[Dave]

I've had three cycles for years- Honda, Yamaha, and Moto Guzzi

 

[vsteel]

Ok, if I was going to take a wild guess on what this thing would be. I would say that it would have an intake just like a conventional 2 stroke and just an exhaust valve. The biggest problem that a 2 stroke has on meeting emissions is not the oil in the gas, but he huge amounts of unburnt/partial burnt gasses that are dumped out into the exhaust. If stihl can controll when the exhaust will open, they could reduce emissions. I would still fire on every stroke, just now it would have a valve. (maybe a rotery valve so rpm would not be that much of a problem)

Actually you could have a pressure oil fed bottom end and not even have the fuel go through there as long as you had a pump to pressurize the mixture and force it into the cylinder. Supercharger anyone???

just my two cents.

 

[confused]

Not to knock the three cycle tech or other ideas, but why cant we go fuel injection? Now im not a design engineer yet (not finished with school) but after taking about enough little two strokes apart it seems to me that there is an easier way to beat the EPA and keep the power up. The idea i have bounced off an couple of my friends is to use two injectors.

Use one injector for the straight gas just as any car does. Now i have a question that i havent found an answer yet. Does a two stroke need to have oil at the top of the piston if there was an oil injector spraying the oil underneath the piston as it gets to the top of the compression stroke. Isnt that where the oil is needed? If this sounds like complete crap just let me know i would like to do some prototyping of sorts on just this type of idea. With use of a small computer and an O2 senser we could at least try to minimize emissions. Like i said if this sounds like a completely hair brained idea im sorry i wasted your time im just trying to find another way to beat those joy killing EPA officials. Because we all know how chainsaw emissions are the cause for the hole in the Ozone.

confused

 

[homelite360]

whell you need the oil to come in through the base so that it will lubricate the lower end so that you do not seize the rod bearing. but some come in though the side so it would have to be timed so that it would spray at the right time so that it would fog the lower end and the cylinder. but give them a few more years and they will have it ironed out. whell McCulloch was on the right track in the later 60 when they had a saw that had mechanical fuel injection like a diesel.

 

[vsteel]

The oil can be sprayed into the bottom end and doesn't have to be mixed into the fuel. Several motorcycles had this style of oil injection. You just put the oil into a separate tank and a small pump that is run off of the crank injects oil into the bottom end. (there is also a connection to the throttle, so that the harder you are on the gas the more oil it will inject into the motor.

You can have an oil system like a 4 stroke on a two stroke if you wanted, the only reason that the oil and fuel is mixed into the bottom end is so that it can be pressurized and forced into the cylinder. If there was another way of doing this (super charger or simular device) the fuel wouldn't even have to go to the bottom end and the two stroke motor would just burn straight gas with no oil mixed in. All of the oil would just stay in the bottom end of the motor, just like it does in a car engine. If I don't miss my guess this is how the old Detroit Diesel and GMC two stroke diesel engines worked.

 

[confused]

To be honest vsteel thats kind of where i started with my idea. Taking alittle from my diesel expierence and from my jet ski rebuilding years. I have a commercial drivers license and pay for school working in the summer driving gravel trucks and had the privilage/horrifying experience of of a tractor with a 671 detroit diesel. As long as i added 2 quarts every morning it was good to go all day long. The detroits used blowers to move the air.

Both you and Mr homelite have come to the same conclusion that i did is that the oil is needed on the bottom end and the crank and if we can get it there we are going to have to recirculate it just like a four stroke. I think my chainsaw idea just got heavier than i want to carry. O well

 

[HUSKYMAN]

You hit the nail on the head, the problem is weight. pumps and injectors and chips and computers and wires all have mass. Of course it can be done look at outboard motors with fuel injection. Sleds have batteryless injection, but they dont weigh 11lbs either. I am going to keep what I have because 10 years from now the next generation will be boasting about how many volts their cordless electric saws have . Except Sonny because lives in California and can only use his saw when they dont have rolling blackouts

 

[les-or-more]

Not to knock the three cycle tech or other ideas, but why cant we go fuel injection? Now im not a design engineer yet (not finished with school) but after taking about enough little two strokes apart it seems to me that there is an easier way to beat the EPA and keep the power up. The idea i have bounced off an couple of my friends is to use two injectors.

Use one injector for the straight gas just as any car does. Now i have a question that i havent found an answer yet. Does a two stroke need to have oil at the top of the piston if there was an oil injector spraying the oil underneath the piston as it gets to the top of the compression stroke. Isnt that where the oil is needed? If this sounds like complete crap just let me know i would like to do some prototyping of sorts on just this type of idea. With use of a small computer and an O2 senser we could at least try to minimize emissions. Like i said if this sounds like a completely hair brained idea im sorry i wasted your time im just trying to find another way to beat those joy killing EPA officials. Because we all know how chainsaw emissions are the cause for the hole in the Ozone.

confused

Not trying to be a wet blanket but the piston will be toast before the bottom end lets go if you don't lube the cylinder walls somehow. Splash lube works as long as the engine remains in an upright position but chainsaws are run on their sides as well.

 

[luckydozenfarm]

my earliest memories as a child was going fishing with my dad and smelling the old 2 stroke Mercs, Evinrudes and Johnsons idling at the boat ramp. Gosh how I miss that smell.

 

[shootingarts]

Well, as long as guesses are flying I'm going to guess some type of reed valve exhaust valve. Built one back in the late eighties for a 1/3 cubic inch Freon compressor. Would have to be scaled up for a chainsaw but weight would be a few ounces. That or some type of rotary valve, a few other thoughts, but none involving camshafts, linkages and such. Converting a two stroke to a four stroke for most practical purposes would make it a heavy pig.

My guess is that they wouldn't even try to bring to market something that weighs over a half pound more unless the government forces their hand or they find a lot of horsepower doing it.

Hu

 

[luckydozenfarm]

also the main benefit of a 2 stroke engine is being able to cut even when the engine is upside down...how are they gonna make that work if it has an oil sump?

 

[pops21]

wow talk about a blast from the past. Oh and look the owner actually used to post on his web site. Whoda thunk?

 

[shootingarts]

Didn't notice somebody had bumped an ancient thread! Trying to get moving today, got to go do errands in town. Since I like that only a little better when it doesn't involve a trip to the dentist I'm not flying out the door.

Hu

 

[jdhacker]

That sounds like the STIHL 4-MIX engine.

 

[les-or-more]

Didn't notice somebody had bumped an ancient thread! Trying to get moving today, got to go do errands in town. Since I like that only a little better when it doesn't involve a trip to the dentist I'm not flying out the door.

Hu

Not sure what is going on I didn't notice the date until now, it was at the top of new posts when I commented.

 

[blsnelling]

I've had the same thing happen to me. All the threads are listed by chronological order descending.

Yes, I think he was talking about the 4-Mix engine.

I honestly didn't know Darin ever participated in the forum. IMHO, that would be a good thing. Come on back Darin!