Stihl switching to fuel injection soon?

[maico490]

tune in next week to our discussion on Laser Disc technology!

That won't catch on.

 

[Chris-PA]

Some cars (automobiles?) went through a phase in the Eighties of carbs that tried to compensate for all sorts of running conditions a bit like the latest carbs on saws. It turned out to be only a half way house to full electronic fuel injection which proved much more reliable. Whether they can make it as light, cheap and small enough for a saw only time will tell. My feeling is that FI will win out.
As regards the cars I had an Audi with one of the "clever" carbs and nightmare does not even come close to describing the pleasure of owning it. I bought it over a fuel injected later model as I thought it would be easier to maintain but got that one wrong.
By the way what are the latest thoughts on VHS or Betamax?

Some feedback carbs worked quite well, but they lacked the advantages of port injection, which included better atomization and fuel distribution. Neither of those are particularly big advantages on a single cylinder 2-stroke where the fuel has to be drawn into the crankcase and then pushed into the cylinder. Injecting it into the cylinder would be huge however, if you could work out the timing to reduce what gets blown out the exhaust.

 

[drkptt]

Don't expect to see direct injection in a chainsaw. Look at the complexity of the three different DI technologies used in big 2-strokes (Optimax, Etec, and HPDI). For example, the Orbital system (Mercury Optimax) has separately-controlled air and fuel injectors (and an air compressor). All have high-draw electrical systems to drive pumps, ECU, injectors, etc.

A chainsaw engine is smaller and runs faster, so the DI system has to better vaporize the fuel, has less time to do it, and has to be more precise. It's not a question of just downsizing components; you need a significantly better system than the ones in production today--systems that already cost hundreds of dollars and suck a lot of power from the engines.

 

[ChainLightning]

If they could make gas like they did 10 years ago then there would be no need for injection. And what are up with these new fixed jet no adjustable carbs? That is a stupid idea. I know it is better for the environment, but what if your saw needs adjustment? You will never see me using a fixed jet carb. Damn EPA needs to consider the OPERATOR before the environment.

 

[user 64030]

Betamax clearly had the better picture .. tune in next week to our discussion on Laser Disc technology!

I'm still stuck on 8-tracks and AM radio.... :eek2:

dw

 

[Chris-PA]

Don't expect to see direct injection in a chainsaw. Look at the complexity of the three different DI technologies used in big 2-strokes (Optimax, Etec, and HPDI). For example, the Orbital system (Mercury Optimax) has separately-controlled air and fuel injectors (and an air compressor). All have high-draw electrical systems to drive pumps, ECU, injectors, etc.

A chainsaw engine is smaller and runs faster, so the DI system has to better vaporize the fuel, has less time to do it, and has to be more precise. It's not a question of just downsizing components; you need a significantly better system than the ones in production today--systems that already cost hundreds of dollars and suck a lot of power from the engines.

I don't disagree, which is why I think a feedback carb makes more sense for a chainsaw.

It's just that the potential benefits of DI would be big in a 2-stroke (I didn't even realize they had any yet), since a 2-stroke is trying to do two things with one stroke and timing is even more important. So if someone could develop a way, even simplified, the benefits might make it worthwhile - and perhaps the Efco mentioned above does that.

 

[stihl86]

They have a model of TS cut off machine coming out with fuel injection sometime in the spring 2012.

When did you hear this? I assume you deal with NES?

 

[zogger]

Hey,

EFCO -Italy-

has certain saw models which are fuel injected using their patented Burn Right devise. It is a special chamber that accumulates fuel mix using a reed valve, and some of the carb mix is sent to the crankcase to lube the lower end bearings, meanwhile, the pressure pulses from the piston charge up the fuel accumulation chamber and use sonic waves to cause the fuel to inject into the chamber through a small port .

I think the MT4000 is a model that has this devise.
No electronics
No bulky parts
No service or adjustments needed

Way cool! First I have heard of it and welcome two strokes into the new century.

Apparently several of their models have this tech, just checked.

 

[sps3172]

I don't disagree, which is why I think a feedback carb makes more sense for a chainsaw.

It's just that the potential benefits of DI would be big in a 2-stroke (I didn't even realize they had any yet), since a 2-stroke is trying to do two things with one stroke and timing is even more important. So if someone could develop a way, even simplified, the benefits might make it worthwhile - and perhaps the Efco mentioned above does that.

I think you just described 'mechanical charge stratification'.

 

[user 64030]

You know....

It dawned on me after reading the M-tronic threads about how the on-board module adjust the carb settings, this could be (by some) confused w/ fuel injection. Since the saw does the choke, the idle and H/L settings it already has the complexity of the ECM. Going from the vacuum draft of a carbureted system to a pressurized direct injection is going to be a jump solely on the basis of how to provide the adequate lubrication.

Although w/ bearings, coatings, and other friction reducing material, I wouldn't be surprised to see a day when saws no longer require oil at all. Maybe a shot of grease w/ every tank of gas and it is good to go....

dw

 

[maico490]

I don't see where this confusion about lubrication is coming from. The fuel will be injected into the air intake in the same place as the carb is now just like in most automobile applications. As it will still be a premix the engine will be lubricated just as it always was.

 

[596 Jason]

I don't see where this confusion about lubrication is coming from. The fuel will be injected into the air intake in the same place as the carb is now just like in most automobile applications. As it will still be a premix the engine will be lubricated just as it always was.

They were talking about direct injection into the cylinder head.

 

[user 64030]

They were talking about direct injection into the cylinder head.

Correct.

In a car the injector is just outside the cylinder and the air/fuel mixes only as it enters the cylinder. The intake manifold is dry. Where a carb on a car mixes fuel/air at the carb creating a wet intake manifold.

Using an injector to inject mix into the crankcase really defeats a lot of the benefits of injection, leaving only the computer controlled tuning. In that aspect M-Tronic and Autotune are already there they control air/fuel via processors. Direct injection is pressurized and gives better atomization, and can be timed to squirt fuel only when needed, after the exhaust window is closed so no fuel is pushed out the exhaust.

dw

 

[tdi-rick]

For the same reason they don't make 4-stroke chain saws now. Turn it upside down and oil hits the piston. It froths the oil, hurts horse power and and some slips by the rings and makes hell of a smoke cloud.

Honda's OPE engines are multipositional for any length of time and four stroke

They mix the oil in the crankcase into a mist.

 

[tdi-rick]

.. didn't Stihl buy carb maker Zama?

Related to this topic?

Several years ago now.
It was reported on here and IIRC the official press release posted.