The new Stihl ms500i

[openspaceman]

12 hours ago, Sawchip said:

Sorry for the de rail...just thought this might be something for anyone interested to see . The animation of the engine is the bit I put this up for.  

It's interesting to see the stratified charge system.

 

I still can't quite figure out the advantage of this Stihl indirect injection into the crankcase other than mixture control, it doesn't seem to do anything  better than stratified charge for  pollution.

[Sawchip]

8 hours ago, openspaceman said:

It's interesting to see the stratified charge system.

 

I still can't quite figure out the advantage of this Stihl indirect injection into the crankcase other than mixture control, it doesn't seem to do anything  better than stratified charge for  pollution.

That is a Makita /Dolmar engine and nothing to do with Stihl. The charge on that engine is controlled by Reeds at the crankcase inlet and then works its way round with ports as well. Its a stratified engine ..."but not as we know it Jim"...It has many still figuring out what the design teem have put into this new engine. 

Stihl Injection.....bottom end still needs lube so the charge "injected or not" ..will need to go in the bottom i guess .

Edited October 9, 2017 by Sawchip

[openspaceman]

28 minutes ago, Sawchip said:

That is a Makita /Dolmar engine and nothing to do with Stihl. The charge on that engine is controlled by Reeds at the crankcase inlet and then works its way round with ports as well. Its a stratified engine ..."but not as we know it Jim"...It has many still figuring out what the design teem have put into this new engine. 

Stihl Injection.....bottom end still needs lube so the charge "injected or not" ..will need to go in the bottom i guess .

I am aware that I was watching a Dolmar rather than the new Stihl, it was blue .

 

I've played with reed valves in bike engines so understand that but Stihl still  indirectly inject into the crankcase, presumably to allow mixing as well as lubrication, it saves the complication of a separate oil tank and injection as well as only requiring low pressure plus much longer dwell for the injection.. However it does nothing to prevent carry over of fuel air mix into the exhaust which is why 2t engines are less economical as well as being dirtier. I don't know whether the chief contribution to their pollution is the fact they have a total loss lubrication or the loss of unburned fuel.

[Sawchip]

40 minutes ago, openspaceman said:

I am aware that I was watching a Dolmar rather than the new Stihl, it was blue .

 

I've played with reed valves in bike engines so understand that but Stihl still  indirectly inject into the crankcase, presumably to allow mixing as well as lubrication, it saves the complication of a separate oil tank and injection as well as only requiring low pressure plus much longer dwell for the injection.. However it does nothing to prevent carry over of fuel air mix into the exhaust which is why 2t engines are less economical as well as being dirtier. I don't know whether the chief contribution to their pollution is the fact they have a total loss lubrication or the loss of unburned fuel.

Yea..i figured out that there were two separate comments to your reply after i posted ..sorry .

Stihl talk about "optimal amounts of fuel being injected in time with the engines cycle" . No spit back and good fuel metering as a start is no bad thing. Taking away the control of the screwdriver over the carb mix (non M tron of corse) will take out varying tune and with temp and case pressure the hole thing is going to be overall much more fuel efficient at the intake point. They can then work on other clever stuff to keep the output cleaner. High pressure direct injection is so much more complex and would require the saw cost to rise way above what is already not going to be cheep. Its got to be a saw that sells after all . I think getting shot of the carb was the way they wanted to go and turning to a Injector ..direct or not ..is the logical progression. 

Edited October 9, 2017 by Sawchip

[openspaceman]

1 hour ago, Sawchip said:

I think getting shot of the carb was the way they wanted to go and turning to a Injector ..direct or not ..is the logical progression.

I agree and had been waiting for it for three years since Hans mentioned it in passing at a Stihl do. Even single point injection on cars was a step forward but then they had lambda sensors in the exhaust.

[Sawchip]

29 minutes ago, openspaceman said:

I agree and had been waiting for it for three years since Hans mentioned it in passing at a Stihl do. Even single point injection on cars was a step forward but then they had lambda sensors in the exhaust.

The TS 500i must have given them some further "real world " feedback . Perhaps the saw will be like going straight to the second generation even though its the first saw made with a injection motor. 

Edited October 9, 2017 by Sawchip

[Macpherson]

Slight derail, but on the subject of alternative engine design I came across this a few years ago. Originally designed for model planes but developed for hand held applications.  

http://www.rcvengines.com/applications_forestandgarden_engines.html

[Chrissy]

So is this new Stihl saw based on the carbon concept saw that was doing the rounds a couple years ago?

[Steve Bullman]

Quite possibly judging by this

 

http://blog.stihl.co.uk/incredible-not-impossible-ultimate-stihl-prototype/

 

In late 2014, we created the STIHL Carbon Concept Chain Saw. This one of a kind saw is made from carbon fibre, titanium and cast magnesium, drastically reducing the weight of the machine without compromising power and durability – it’s the weight size of an MS 362 with even more power than a MS 661.

 

 

 

[Sawchip]

 

Notice there is no number on the disk yet .