Husqvarna engine

[adw]

Not sure if this will open, however it is a Blair tube exhaust engine to reduce emissions Husqvarna had on a back pack blower.

 

 

[Khriss]

Interesting ( on Android) some amazing videos of engineering crap out there now, kE rounds hitting armour are good. K

[Macpherson]

1 hour ago, adw said:

Not sure if this will open, however it is a Blair tube exhaust engine to reduce emissions Husqvarna had on a back pack blower.

If you like that solution you'll like this one as well and it's much simpler, I posted this a few years ago on here but got no replies... sorry it's not a Husky 🙄

 

At the time they were looking for a partner in the forest / garden machinery sector to help with develop their chainsaw / strimmer engine which then was 35cc, it seems as they found one, cheers.

 

 

RCV Engines Home | Specialists in multi-fuel engine technology

RCVENGINES.COM

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RCV Engines are specialists in multi-fuel engine technology which are ideal for your engine needs inclding generator...

 

RCV Handheld Engines for use in Forests and Gardens

RCVENGINES.COM

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If you're looking for an engine that is ideal for forest and garden use then the RCV Handheld Engines is the ideal...

 

[spudulike]

2 hours ago, adw said:

Not sure if this will open, however it is a Blair tube exhaust engine to reduce emissions Husqvarna had on a back pack blower.

 

 

Engine.AVI

I think most of this vid will go over peoples heads but from what I can see, the unburnt fuel on the scavenging of the combustion chamber that typically is blown out of the exhaust on non strato saws (why two strokes are dirty) enters a sealed tube along with the exhaust, and the back pressure allows this to blow back in to the combustion chamber and then only the burnt exhaust gasses enters the muffler as the piston seals the exhaust port after the unburnt scavenging fuel vapour is pumped back in to the engine.

A bit similar to a tuned expansion pipe using the exhaust shock wave to pop the unburnt fuel in to the engine or the way strato engines work.

Interesting stuff if you can understand how two strokes function....not sure many do TBH!

[Stubby]

2 minutes ago, spudulike said:

I think most of this vid will go over peoples heads but from what I can see, the unburnt fuel on the scavenging of the combustion chamber that typically is blown out of the exhaust on non strato saws (why two strokes are dirty) enters a sealed tube along with the exhaust, and the back pressure allows this to blow back in to the combustion chamber and then only the burnt exhaust gasses enters the muffler as the piston seals the exhaust port after the unburnt scavenging fuel vapour is pumped back in to the engine.

A bit similar to a tuned expansion pipe using the exhaust shock wave to pop the unburnt fuel in to the engine or the way strato engines work.

Interesting stuff if you can understand how two strokes function....not sure many do TBH!

Sorta EGR stuff ?

[Stere]

Quote

At the time they were looking for a partner in the forest / garden machinery sector to help with develop their chainsaw / strimmer engine which then was 35cc, it seems as they found one, cheers.

 

So what brand  products will have thoose RCV engines on them?

 

Seem like an old idea?

 

Spin Doctors: The Rotary Valve Cylinder Head - Old Bike Australasia

WWW.OLDBIKEMAG.COM.AU

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The rotary valve cylinder head has been around longer than the motorcycle, falling into, and out of favour on a regular basis...

 

[Stere]

Blair tube exhaust so has some history of development?

 

Is this  that blair bloke?

Yorkshire Ferret: Gordon Blair: Seeley G50 Exhaust System

YORKSHIREFERRET.BLOGSPOT.COM

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In 1969 Gordon Blair designed a radical new racing exhaust system for the ageing Matchless G50 engine.   The design of...

 

[Macpherson]

1 minute ago, Stere said:

 

So what brand  products will have thoose RCV engines on them?

 

Seem like an old idea?

 

Spin Doctors: The Rotary Valve Cylinder Head - Old Bike Australasia

WWW.OLDBIKEMAG.COM.AU

---

The rotary valve cylinder head has been around longer than the motorcycle, falling into, and out of favour on a regular basis...

 

 

I am not up to date with these RCV's but I think they were initially developed for model aeroplanes.

 

The concept goes right back to the start of engine development with many different rotary valve designs  many of which were dropped due to lack of engineering tolerances and sealing issues, there's an old book titled ' Valve mechanisms for high speed engines ' by P Smith which had many different designs illustrated.

 

Back in the 40's there was an English guy  Frank Aspen who experimented with rotary valved Velocette's and got great performance with very high compression ratios but could never get the sealing problem to be reliable and they burnt too much oil.

[openspaceman]

2 hours ago, Macpherson said:

 

 

 

Back in the 40's there was an English guy  Frank Aspen who experimented with rotary valved Velocette's and got great performance with very high compression ratios but could never get the sealing problem to be reliable and they burnt too much oil.

Yes that was a rotating conical valve in the head. The ultimate WW2 aero engines were sleeve valved H layout but again the cost of the performance was loss of lubrication oil.

 

 

Edited December 2, 2021 by openspaceman
one war too many

[adw]

2 hours ago, spudulike said:

I think most of this vid will go over peoples heads but from what I can see, the unburnt fuel on the scavenging of the combustion chamber that typically is blown out of the exhaust on non strato saws (why two strokes are dirty) enters a sealed tube along with the exhaust, and the back pressure allows this to blow back in to the combustion chamber and then only the burnt exhaust gasses enters the muffler as the piston seals the exhaust port after the unburnt scavenging fuel vapour is pumped back in to the engine.

A bit similar to a tuned expansion pipe using the exhaust shock wave to pop the unburnt fuel in to the engine or the way strato engines work.

Interesting stuff if you can understand how two strokes function....not sure many do TBH!

I just thought it was a good animation to show a two stroke working, unfortunately the Blair tube did not really catch on, but we dis sell a good number of this blower, the 356BTS.