Atkinson engine cycle video

[obob]

It helped me understand how the atkinson engine works.

 

Compares atkinson with conventional gas engine

 

Edited August 21, 2014 by obob

[plus 3 golfer]

Great find.

 

Technically, the video is simulating the efficiency gains of an Atkinson cycle engine by effectively shortening the intake stroke by leaving the intake valve open for part of the compression stroke.  Here's a video of a true Atkinson cycle engine.  It uses a conventional Otto cycle engine and "the clever arrangement of levers ... to cycle the piston through all four strokes in only one revolution of the main crankshaft, and allows the strokes to be different lengths..The Atkinson cycle in the Lexus video (like the Otto engine) takes two revolutions of the crankshaft to complete the cycle. 

[nsteblay]

I believe Ford uses an approach similar to the Lexus versus a true Atkins.  What I don't understand is the trade off.  If Atkins is more fuel efficient why isn't every engine an Atkins?

[jdbob]

If Atkins is more fuel efficient why isn't every engine an Atkins?

 

I believe it's because they have poorer low-end torque. But since the electric motor has excellent low-end torque it won't be missed so it's fine for a hybrid.

[kostby]

I believe Ford uses an approach similar to the Lexus versus a true Atkins.  What I don't understand is the trade off.  If Atkins is more fuel efficient why isn't every engine an Atkins?

 

Because not everyone likes a low-carb diet.  ;)

www.atkins.com

Edited August 24, 2014 by kostby

[drdiesel1]

I believe it's because they have poorer low-end torque. But since the electric motor has excellent low-end torque it won't be missed so it's fine for a hybrid.

Yep, that's it :victory:

[obob]

from

http://green.answers.com/auto-industry/a-basic-introduction-to-how-the-atkinson-cycle-engine-works

 

The goal of equal pressure

 

As the internal air pressure increases with each cycle, the purpose of the Atkinson cycle is to make the combustion chamber's air pressure at the end of a power stroke to be the same as atmospheric pressure. At this point, the combustion process has yielded all of its available energy, meaning that you have maximized the efficiency in the system. The more energy that an engine converts from heat to mechanical energy, the more efficient the engine.

 

( notes added by obob

   1. or a lot closer to atmospheric pressure than the otto[conventional] engine.

   2. so by returning some of the intake gas to the intake manifold, the amount of gas-air left allows for an efficient burn. )

Edited August 29, 2014 by obob

[BoomerGer]

Because not everyone likes a low-carb diet.  ;)

www.atkins.com

Sure, and for the same reason that you can still get a v/8 in something just so you can smoke the tires from a stop, and chirp them as you go thru the gears!