Clever idea, damping the cylinder peak pressure - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Insert BS here A place to discuss anything you want

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 05-01-2012, 01:25 PM   #1
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Aug 2008
Location: Granada, Spain
Posts: 336
Total Cats: 2
Default Clever idea, damping the cylinder peak pressure

You'll probably think of the added weight problems, aside from that I find it impressive.

Attached Thumbnails
Clever idea, damping the cylinder peak pressure-rod.jpg  
ismael_pt is offline   Reply With Quote
Old 05-01-2012, 01:27 PM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,847
Total Cats: 1,788
Default

arrow 28 points where the rod will bend.
Braineack is offline   Reply With Quote
Old 05-01-2012, 01:33 PM   #3
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Aug 2008
Location: Granada, Spain
Posts: 336
Total Cats: 2
Default

Quote:
Originally Posted by Braineack View Post
arrow 28 points where the rod will bend.


Actually 28. is the point to remove weight with a sawzall if needed.
ismael_pt is offline   Reply With Quote
Old 05-01-2012, 03:21 PM   #4
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by Braineack View Post
arrow 28 points where the rod will bend.
not until 36 rusts solid.
y8s is offline   Reply With Quote
Old 05-01-2012, 06:55 PM   #5
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

How this supposedd to wirk

Flexy rod goes boing?????!
Faeflora is offline   Reply With Quote
Old 05-01-2012, 06:56 PM   #6
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

I see some wackassness like this possibly being uswful in valveyrain. Like if ur cylinder kerbloses then the camshat shhits over to the side and pop the valves open and voosh goes the detonations
Faeflora is offline   Reply With Quote
Old 05-01-2012, 06:59 PM   #7
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Aug 2008
Location: Granada, Spain
Posts: 336
Total Cats: 2
Default

Quote:
To provide peak cylinder pressure control, an eccentric bearing is biased toward a first angular position wherein an attached piston is raised to a maximum compression ratio position in the cylinder. The compression ratio may remain constant at lower loads and above until a predetermined force generated by cylinder pressure is reached. At this point, the force acting on the eccentric lever arm or eccentricity of the bearing overcomes the restraining biasing force, causing the eccentric bearing to rotate in the connecting rod to move the eccentric end of the rod outward, away from the cylinder. This motion effectively shortens the length of the connecting rod and moves the piston downward relative to a connected crankpin. In this manner, the effective compression ratio of the cylinder is temporarily reduced and the pressure developed in the cylinder is controlled by the mechanical mechanism.

http://www.freepatentsonline.com/6701885.html
ismael_pt is offline   Reply With Quote
Old 05-01-2012, 07:22 PM   #8
Senior Member
iTrader: (1)
 
BogusSVO's Avatar
 
Join Date: Mar 2012
Location: Pensacola Fla.
Posts: 590
Total Cats: 191
Default

Looks like more parts to break and fail.

Also it would decrease peak HP, by lowering the CR

Neat in theory, but I do not see the use of it.
BogusSVO is offline   Reply With Quote
Old 05-02-2012, 02:45 AM   #9
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

Quote:
Originally Posted by BogusSVO View Post
Also it would decrease peak HP, by lowering the CR
I'm still trying to wrap my head around it, but in theory, the system should not start to decrease effective CR until chamber pressure exceeds the pressure needed to deflect the spring. So this is more like an engine with a dynamically variable compression ratio. That would allow you to run more boost without detonation while still maintaining efficiency at low to moderate load conditions.

(I think.)
Joe Perez is online now   Reply With Quote
Old 05-02-2012, 02:53 AM   #10
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Why over-complicate things?
Just use rubber rods. They will never break. NEVAR
18psi is offline   Reply With Quote
Old 05-02-2012, 10:44 AM   #11
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,847
Total Cats: 1,788
Default

im sorry, im no engineer, but does not the rod still have to bend in order to compress/contract the spring?

also, it's probably not a good thing to have a spring rub your cylinder walls right?



BTW I just invented a new stlye of coilbesides.

Attached Thumbnails
Clever idea, damping the cylinder peak pressure-new_shock.jpg  

Last edited by Braineack; 05-02-2012 at 11:04 AM.
Braineack is offline   Reply With Quote
Old 05-02-2012, 11:28 AM   #12
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,847
Total Cats: 1,788
Default

just sent to the patent office!!!!! time to go on the Shark Tank!
Braineack is offline   Reply With Quote
Old 05-02-2012, 11:30 AM   #13
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,132
Total Cats: 187
Default

From my non-engineer observation

The bottom end of the spring is not attached to the big end of the rod, it is attached, instead, to the crankshaft, the big end and the lower spring are therefore independent of one another.

The big end is attached to the crankshaft via eccentric bearing (correct?) The spring holds the rod in the "up" position until too much compression is achieved, at which point the compression forces the rod downward causing it to rotate on the eccentric bearing to the furthest "down" point, which compresses the spring. At the end of the exhaust stroke, the load on the piston is reduced and the spring un-compresses, which rotates the big end of the rod back to the "up" position.

End of non-engineer observation

Beginning of non-engineer logic

In practice, it looks like a failboat idea. If the spring is strong enough to rotate the friction surface of the eccentric bearing back to the "up" position, then the combustion event is going to be able to overpower the spring + friction on every single combustion stroke, which means that the cylinder is *not* variable compression - it is *minimum* compression every time.

Oh, and then you've got the added weight and complexity of the system.

Here's an alternative use for this application:

If you could find a way to lock the rod in the "up" position on the combustion stroke, and unlock the rod on the intake stroke, you would have a piston which could theoretically stay "down" longer at higher RPMs on the intake stroke as the inertia of the piston + rod overcomes the upward force applied by the spring, which could result in a more valuable intake stroke...

Intake stroke begins, rod is in the "up" position, relative to the crankshaft. Dynamic locking system on the eccentric bearing "unlocks" as the downstroke begins.

At the bottom of the intake stroke, the cylinder is pulling maximum vacuum through the intake ports. Crankshaft transitions from the intake stroke to the compression stroke. The downward inertia of the rod/piston momentarily overcomes the force applied by the spring, and very briefly continues downward before shooting back upwards. The force of inertia is increased as RPMs increase, thereby pulling more vacuum across the intake valves as the engine spins up which helps to reduce torque drop-off at high RPMs. At the very bottom of the intake stroke, the "locking crankshaft" re-activates the locking mechanism - since the rod has already moved away from the lock catch, the locking mechanism stays activated but not engaged, ready to "catch" the piston once it returns to the full up position.

Approximately halfway through the compression stroke, the spring has returned the piston to the full "up" position. The compression in the cylinder at this point is a mere 2:1, not nearly enough to overcome the spring force. The activated locking system immediately re-engages the lock catch, holding the piston in the full up position. The locking mechanism stays activated and engaged throughout the remainder of the compression stroke, and the full combustion and exhaust strokes before de-activating once more for the next intake stroke.

Cool theory, but how to unlock during the intake stroke while keeping it locked during the combustion stroke? I don't know - I'm going to go take a crap and work-out now.
fooger03 is offline   Reply With Quote
Old 05-02-2012, 11:38 AM   #14
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,847
Total Cats: 1,788
Default

Quote:
Originally Posted by fooger03 View Post
The bottom end of the spring is not attached to the big end of the rod, it is attached, instead, to the crankshaft, the big end and the lower spring are therefore independent of one another.

that makes a little more sense.
Braineack is offline   Reply With Quote
Old 05-02-2012, 12:08 PM   #15
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

This does seem to be an excessively complicated solution, to say nothing of connecting rod not hit block.
Joe Perez is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 09:37 PM.