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  #11  
Old 10-14-2016, 04:05 PM
Johnincali Johnincali is offline
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Default Re: Dolphin powered bike... a different kind of 2 stroke

here's a picture of the original Dolphin...


you can read about the Dolphin engine here... http://www.oldengine.org/members/die...sc/ricardo.htm

or here.... http://www.oldengine.org/members/die...sc/ricardo.htm

Ricardo designed it in 1904 when he was just 17 years old... it was know for it's smooth running and high torque.. Around 1908 they made a car called a Dolphin that used the engine... it was also popular in boats.. Never hear of one in a motorcycle though...

I also added a 2 speed....

Last edited by Johnincali; 10-14-2016 at 04:29 PM.
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  #12  
Old 10-14-2016, 04:30 PM
Johnincali Johnincali is offline
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Default Re: Dolphin powered bike... a different kind of 2 stroke

You can also read more about the Dolphin engine here...https://books.google.com/books?id=Jl...page&q&f=false

Last edited by Johnincali; 10-14-2016 at 06:01 PM. Reason: add link
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  #13  
Old 10-15-2016, 03:04 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Dolphin powered bike... a different kind of 2 stroke

Thanks for that link.

https://www.youtube.com/watch?v=BwLQ-Zfk36Y

A marine version and hear it does idle very slow.

Most 2 stroke cycle engines have a much higher idle speed.

I did see another book on Google Books see this at page 16 near the bottom 1/3 of the page.

https://books.google.com/books?id=6z...umanis&f=false

Now on page 16 see the area where it mentions of the rate of burn speed by the changing of turbulence in the cylinder by changing the diameter of the tube between then two cylinders. The more turbulence it was said made faster burn. A compromise between fast and slow burn got a quiet engine with good fuel usage. Maybe this is how I can hear the difference between a normal 2 stroke engine and this type where it can idle very slow.

MT

One more Youtube video of one of these engines in a boat.

https://www.youtube.com/watch?v=zeXplu6kSUE

Last edited by MEASURE TWICE; 10-15-2016 at 03:07 AM.
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  #14  
Old 10-15-2016, 09:09 AM
Johnincali Johnincali is offline
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Default Re: Dolphin powered bike... a different kind of 2 stroke

Hi MT, Those engines are typical 2 stroke boat engines manufactured by a company called Dolphin in the 1950's and 60's ... They are not the same as the original dolphin type engine that uses a piston to charge the cylinder... http://www.dolphinengines.co.uk/history.php

Also I think most of the reason the Dolphin runs smooth is because it uses top / down uniflow scavenging... this causes the fuel / air near the spark plug to be in an ideal state for combustion. Ricardo also used a narrow passage to ensure the engine idled smoothly but IMO a narrow passage is also wasteful and not the best answer. I developed a different combustion chamber design which also allows for smooth running.

Most small carbureted 2 strokes use ether cross or loop scavenging which tends to not idle smooth... they also loose a portion of the unburned fuel out the exhaust which makes them not good from an emissions standpoint.

http://www.airplanesandrockets.com/m...b-1968-aam.htm

Modern low emission engines like the E tech and Orbital use a system that injects the fuel after the exhaust port is covered.

https://www.youtube.com/watch?v=eu3NEPSBfUs

Last edited by Johnincali; 10-15-2016 at 08:41 PM.
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  #15  
Old 10-15-2016, 11:37 AM
Johnincali Johnincali is offline
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Default Re: Dolphin powered bike... a different kind of 2 stroke

If you are interested about some of the history of the 2 stroke engine...

https://www.smokstak.com/forum/showt...115633&page=19

Here's some good info on the Dolphin history... page 6 talks about smooth idle...

http://sias2.pastfinder.org.uk/sih_1...08/02-1971.pdf

Last edited by Johnincali; 10-15-2016 at 10:22 PM.
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