# Atkinson Cycle



## putputman (Jul 12, 2009)

I finally test run my Gingerly Atkinson Cycle Engine. I started it last fall when I started the New Holland engine. Each time I got to the point I had to walk away from the New Holland, I would work on the Atkinson, Elmer's Tiny, Chuck Fellows Hit & Miss, Chuck Fellows John Deere, and Brian's Slinky.

I still have some "bling" to do on this engine. Once I get a suitable ignition system I will complete the base for it and may paint it the aluminum. 






I had to modify the carburetor. I couldn't get the Gingerly design to run.





This is the valve system.






This might be a good I.C. engine for people that want to avoid making or buying gears. It get four cycles by using linkages instead of gears.


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## cfellows (Jul 12, 2009)

Great looking engine and a fine runner. Nice work! :bow:


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## Maryak (Jul 13, 2009)

Another Masterpiece :bow: :bow:

Best Regards
Bob


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## Foozer (Jul 13, 2009)

I'll just sit here and drool all over myself.


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## putputman (Jul 14, 2009)

Thanks for the kind words guys. It is always nice when a new engine comes to life.

It won't be long and we will see Bob's "hit & miss" come to life. You have really been moving along nicely on that project, especially considering that fact that you are in the midst of building a new home at the same time. You guys "down under" must have more than 24 hrs in a day.

Fooz, I don't think I have ever seen as much work done on a lathe as what you do. Some of your milling setups are fascinating. I have never tried milling on a lathe.

Chuck, I hope you get settled in and get the shop setup pretty soon. I counting on that "air Hoglet" for one of next winters projects.

Thanks again


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## b.lindsey (Jul 14, 2009)

Beautiful engine Arv. Looks to be a nice smooth runner too from the video. Thanks for sharing it!!

Bill


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## Noitoen (Jul 14, 2009)

Curious, my car has a 1500cc Atkinson Cycle 4 cyl engine ;D


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## kvom (Jul 14, 2009)

I'll bet if you get all the other engines I see in the video going at the same time you will really hear some put-puting.  ;D

Nice Job!


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## putputman (Jul 14, 2009)

Helder, I have seen some of those articles on the internet about Ford, Toyota, Honda, etc. using some kind of a version of Atkinson engines. I'm sure it doesn't use linkages like mine or you wouldn't be able to hand on to it at fast speeds. I don't know what the connection to Atkinson is.

Kvom, each engine has its' own gas tank, but I normally use one auxiliary tank to run each engine. They run so seldom that the gas would deteriorate if I left it in each tank. I also use the same battery on most of them.


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## vlmarshall (Jul 14, 2009)

putputman  said:
			
		

> Kvom, each engine has its' own gas tank, but I normally use one auxiliary tank to run each engine. They run so seldom that the gas would deteriorate if I left it in each tank. I also use the same battery on most of them.



So, a big manifold... and a bussbar... ;D


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## d-m (Jul 14, 2009)

Vary nice well done may I ask what the stroke and bore dimensions are watching the video you can barely tell there is a stroke lol
Thanks Dave


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## Noitoen (Jul 15, 2009)

putputman  said:
			
		

> I don't know what the connection to Atkinson is.



According to Toyota,_ "The Atkinson cycle shifts the traditional four-cycle engine's method of intake, compression, power, and exhaust. The Atkinson cycle has a longer power stroke than compression stroke, which enables the engine to produce more power in a certain operating range. The 12- to 14-percent gain in efficiency versus an Otto-cycle engine is mainly due to the reduction in pumping losses, or the amount of energy needed simply to suck air into the cylinders and then expel spent exhaust gases."_

The crankshaft is slightly off-centre from the cylinders so the piston's "speed" is different going up and down. The gain in efficiency has a drawback since the engine has less torque at low RPM. With a hybrid system this doesn't matter because the electric motor has a very high torque (in my case 400Nm) almost from standstill. The transmission system is represented in my avatar with a clutchless continuous variable transmission. 

I try to find a link with an animated representation of the system.


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## putputman (Jul 15, 2009)

Dave, my engine has a 1-1/4" bore and the stroke is different on each movement. 
Intake = .855"
Compression = .705"
Power = 1.020"
Exhaust = 1.168"
It might be easiest to understand if you go to this site and watch the animated example and apply my dimension to the model. You can slow the animation down to really see it good.
http://www.animatedengines.com/atkinson.shtml


Helder, if I understand you correctly, the newer cars that have a so called "Atkinson System", basically achieve what Atkinson did with linkages, but are doing it with gears, or cams, or computer, or what ever. Am I close??


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## Noitoen (Jul 15, 2009)

Just by shifting the centre of the crankshaft in relation to the centre of the cylinder you get that different "stroke speed". If will see a similar effect if you look closely at this engine http://www.homemodelenginemachinist.com/index.php?topic=5461.0 when it turns, you will see the difference in the "up/down" stroke. In the modern engines they do play a little with the valve timing and since these engines are direct fuel injected, before they "add" the fuel, they can keep the intake valve open a little past the intake stroke letting some of the air it "sucked" out again and by doing this they are literally reducing the "size" of the engine. By this you can reduce fuel consumption when you don't need the power. 

This is a sample of the valve "works" in a normal engine [ame=http://www.youtube.com/watch?v=MR63IrKHv7E&feature=related]http://www.youtube.com/watch?v=MR63IrKHv7E&feature=related[/ame]


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## kustomkb (Jul 15, 2009)

Great engine Arv!! 

Looks very nice and has a great rhythm too!


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