Atkinson Cycle in F1

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.

Post Fri Jun 26, 2009 5:19 am

I've recently read a bit about Atkinson cycle engines which, as I understand, allow the expansion stroke to differ from the compression stroke in a four stroke cycle. Anyone here know if these engines permitted and applicible to F1 or any other form of motorsport?
FGD
 
Joined: 13 Feb 2008

Post Sat Jun 27, 2009 4:33 am

FGD,

Technically, an Atkinson Cycle (ie. an over-expanded 4-stroke) would be legal in F1, but would not be of any benefit. The bore dimensions and displacement of F1 engines are tightly regulated, so an F1 engine with the reduced compression stroke that an Atkinson Cycle would require would yield slightly better thermal efficiency. But unfortunately, it would also yield substantially less horsepower.

A case of "great in theory, but not in practice".

Good question though.
Best regards,
Terry
"Q: How do you make a small fortune in racing?
A: Start with a large one!"
riff_raff
 
Joined: 24 Dec 2004

Post Sat Jun 27, 2009 6:26 am

Thanks Terry. In light of the fact that refueling is banned for 2010, I wondered if the increased fuel efficiency of an Atkinson might seem an interesting option.

Several manufacturers are using "virtual" Atkinson engines - whatever that means - in their road cars (Toyota and Ford come to mind) but Honda is presently developing a mechanical Atkinson which they say yields 20% fuel savings.

I'm wondering if the fuel/weight savings might offset the loss of power.
FGD
 
Joined: 13 Feb 2008

Post Sat Jun 27, 2009 1:48 pm

The new 2010 Prius uses an Atkinson 1.8 liter DOHC. The engineers at the product intro say the Atkinson gives more power at highway speeds at the cost of some low-end torque.

FWIW, the 1.8 is detuned in the sense that it uses VVT only on the exhaust cam, while VVT is used on both camshafts when the same engine is used in the Corolla.
Enzo Ferrari was a great man. But he was not a good man. -- Phil Hill
donskar
 
Joined: 3 Feb 2007
Location: Texas, USA

Post Sat Jun 27, 2009 8:28 pm

Here's a good illustration of what Honda is working on.

http://www.roadandtrack.com/article.asp ... le_id=8173
FGD
 
Joined: 13 Feb 2008

Post Sat Jun 27, 2009 9:05 pm

There might be also some problem on spinning all that at 18000rpm...
rjsa
 
Joined: 2 Mar 2007

Post Sat Jun 27, 2009 10:40 pm

rjsa wrote:There might be also some problem on spinning all that at 18000rpm...

Sure. That's a lot of mass spinning around the crankshaft and I've got to think that balancing and controlling vibration might be serious undertakings.
FGD
 
Joined: 13 Feb 2008

Post Tue Jun 30, 2009 1:46 am

I think it can be made to do 19,000 rpm.
Notice some of the parts just move up and down, not really rotating with the crank itself.

Sound crazy.. but I think they can do it.. Maybe with Titanium parts..lol
"I was blessed with the ability to understand how cars move," he explains. "You know how in 'The Matrix,' he can see the matrix? When I'm driving, I see the lines."
n smikle
 
Joined: 12 Jun 2008

Post Tue Jun 30, 2009 3:12 am

n smikle wrote:I think it can be made to do 19,000 rpm.
Notice some of the parts just move up and down, not really rotating with the crank itself.

Sound crazy.. but I think they can do it.. Maybe with Titanium parts..lol

I don't know where you're getting than 19000 rpm figure from but what I'm more interested in is the 20% fuel savings Honda claims the engine is capable of delivering.

My thinking is as follows: with re-fueling banned for 2010, cars must start with about 45-50 gallons of fuel. That's roughly 170kg of fuel. If the Atkinson can deliver 20% fuel savings, cars using it can run with just 140kg of fuel - a 30kg savings! That's some serious weight savings by F1 standards!

And then there's the prospect of getting to design a car with a fuel tank 20% smaller than conventionally engined cars - thus improving weight distribution and reducing the complexity of setting-up a car to run well as fuel is depleated over the course of a race.

Well... I'm still unsure if the Atkinson cycle is legal in F1 and hope someone can enlighten me me before I start building my own entry for 2010.
FGD
 
Joined: 13 Feb 2008

Post Tue Jun 30, 2009 4:54 am

Variable valve timing is illegal in F1 and in 2010 probably all the way to 2014 engines will be frozen, unless they decide changes to this.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)
WhiteBlue
 
Joined: 14 Apr 2008
Location: WhiteBlue Country

Post Tue Jun 30, 2009 5:20 am

WhiteBlue wrote:Variable valve timing is illegal in F1 and in 2010 probably all the way to 2014 engines will be frozen, unless they decide changes to this.

Atkinson Cycle, as opposed to Otto or Miller cycle, has nothing to do with variable valve timing. Aktkinson Cycle allows for physical variations in piston stroke by utilizing a multi-link connecting rod and crankshaft creating longer expansion and exhaust strokes in four stroke engines.

Have a look at the video:

http://www.roadandtrack.com/article.asp ... le_id=8173

And some more information:

http://en.wikipedia.org/wiki/Atkinson_cycle
FGD
 
Joined: 13 Feb 2008

Post Tue Jun 30, 2009 9:31 am

Apparently there is a simulated Atkinson cycle which isn't done by different strokes, but by valve changes. My remarks apply to that type of application.

Looking at the linkage of the true Atkinson cycle in the video I would not see that fit for F1 engine speeds (18.000 rpm). I seriously doubt that you can get this type of linkage to half the speed.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)
WhiteBlue
 
Joined: 14 Apr 2008
Location: WhiteBlue Country

Post Tue Jun 30, 2009 4:05 pm

The philosophy behind the Atkinson cycle is for the exhaust gases to be at the same pressure as the ambient air when the exhaust valve opens. Currently, there appear to be two different mechanical methods to achieve this. The first, and presently common on production engines is for the intake valve to delay closing long past top dead center. In fact, gases get blown back out the intake port. This is that WB is referring to. The second method is to have some kind of monky motion linkages designed so that the compression stroke is less than the exhaust stroke.
The proble is that the Atkinson cycle is for efficiency, and not power. The entire concept of power is to get as much oxygen and fuel into the combustion chamber and light the fire. The theory of the Atkinson cycle is to introduce specific amount of air and fuel into the combustion chamber, allow it to burn, but to allow the expanding gases to expand and produce power until the exhaust gas expansion has ceased, then allow it to exit the engine.
It's like asking a trained marathon runner to suddenly compete in powerlifting. Fundamentally incompatible.
Beer is cheaper than therapy.
DaveKillens
 
Joined: 20 Jan 2005

Post Thu Jul 02, 2009 3:46 am

The Atkinson cycle is more powerful If it has the same compression ratio with the same amount of air inhaled as a similar sized conventional engine because it is more efficient. Riiigt?

So If they had this engine in F1, they could dial back the power to "normal" levels to save fuel.

FGD wrote:I don't know where you're getting than 19000 rpm figure from but what I'm more interested in is the 20% fuel savings Honda claims the engine is capable of delivering.

My thinking is as follows: with re-fueling banned for 2010, cars must start with about 45-50 gallons of fuel. That's roughly 170kg of fuel. If the Atkinson can deliver 20% fuel savings, cars using it can run with just 140kg of fuel - a 30kg savings! That's some serious weight savings by F1 standards!

And then there's the prospect of getting to design a car with a fuel tank 20% smaller than conventionally engined cars - thus improving weight distribution and reducing the complexity of setting-up a car to run well as fuel is depleated over the course of a race.

Well... I'm still unsure if the Atkinson cycle is legal in F1 and hope someone can enlighten me me before I start building my own entry for 2010.


Remember your car has to be powerful enough so you can finish the race in first! I just picked 19,000rpm because you have to over design the engine.. can even choose 21,000 rpms!
"I was blessed with the ability to understand how cars move," he explains. "You know how in 'The Matrix,' he can see the matrix? When I'm driving, I see the lines."
n smikle
 
Joined: 12 Jun 2008

Post Thu Jul 02, 2009 4:33 am

n smikle wrote:The Atkinson cycle is more powerful If it has the same compression ratio with the same amount of air inhaled as a similar sized conventional engine because it is more efficient. Riiigt?

So If they had this engine in F1, they could dial back the power to "normal" levels to save fuel.

FGD wrote:I don't know where you're getting than 19000 rpm figure from but what I'm more interested in is the 20% fuel savings Honda claims the engine is capable of delivering.

My thinking is as follows: with re-fueling banned for 2010, cars must start with about 45-50 gallons of fuel. That's roughly 170kg of fuel. If the Atkinson can deliver 20% fuel savings, cars using it can run with just 140kg of fuel - a 30kg savings! That's some serious weight savings by F1 standards!

And then there's the prospect of getting to design a car with a fuel tank 20% smaller than conventionally engined cars - thus improving weight distribution and reducing the complexity of setting-up a car to run well as fuel is depleated over the course of a race.

Well... I'm still unsure if the Atkinson cycle is legal in F1 and hope someone can enlighten me me before I start building my own entry for 2010.


Remember your car has to be powerful enough so you can finish the race in first! I just picked 19,000rpm because you have to over design the engine.. can even choose 21,000 rpms!

What true Atkinson Cycle (other than the one in your head) has revved to 19,000 or 21,000 rpm? The only engines presenty using a true Atkinson cycle (to my knowledge) are a Honda prototype:
http://www.roadandtrack.com/article.asp ... le_id=8173
and the standard Wankel rotary engine:
http://en.wikipedia.org/wiki/Atkinson_cycle
While I appreciate your imagination, I'd like to see some facts to back it up.
Ri-ight.
FGD
 
Joined: 13 Feb 2008

Next

Return to Engine, transmission and controls

Who is online

Users browsing this forum: CCBot [Bot], Exabot [Bot] and 9 guests