All it takes is four slim and lightweight secondary connecting rods and one thin and lightweight crankshaft, i.e. 5 lightweight, and cheap to make, moving pieces in total, plus one slow moving control frame.
A modified V-8 patcrank VCR has as vibration-free-operation as the original conventional V-8, no matter what the selected compression ratio is.
The rev limit is as high as the rev limit of the original engine.
The range of available compression ratios of the patcrank VCR is as wide as desirable, for instance from below 7:1 to above 20:1.
A VCR can help the big displacement engines to pass current and future CO2 emission regulations.
Thats a hell of a design! And a hell of a website, certainly one to overload the brain in a few seconds, not sure how the designs would fare in racing due to the higher number of smaller bearings and moving parts etc, but incredible designs.
manousos wrote:
The range of available compression ratios of the patcrank VCR is as wide as desirable, for instance from below 7:1 to above 20:1.
A VCR can help the big displacement engines to pass current and future CO2 emission regulations.
Thanks
Manousos
20:1?????? not without flat diesel heads, very little valve lift and duration and a LOT of detonation!
Why would anyone want to lower the compression ratio in their engine lower than the safe maximum? High compression ratio engine are cleaner, more efficent and more powerful... if it was based on changing fuel octane, then it would be cheaper to buy lots of that octane booster stuff!
Because you can run it in conjunction with a turbo and lower the CR for full boost
Also make the CR throttle dependent as part throttle the effective cylinder pressures are lot lower so for pootling you raise the CR and lower it when you open the taps
[quote="crayefish"][quote="manousos"]
. . . lol: not without flat diesel heads, very little valve lift and duration and a LOT of detonation . . . [/quote]
Take a look at the desmodromic VVA (and the rest VVAs) in pattakon web site. At high compression ratios (which fit to partial load operation) the valve lift can be quite short (for good aspiration of the engine at 2000 rpm and full load you need less than 3mm peak valve lift, at partial load you need less).
The complete solution has compression control and valve lift/duration control.
Without VVA you need pockets on the piston crown.
With normal engines there seem to be problems keeping the crank located in the block, and even the block stiff enough. I can't see how it could be achieved realistically when you are moving the crank up and down, or am I missing something? I know we all think of cranks and rods as being stiff components, but I've always been led to believe that in anger they do flex by proportional margins and that the stiffer you make them the greater requirement for stress related properties? These bendy vs stiff visualizations always do my head in a bit though just like micro and macro stuff fine whilst you consider just one viewpoint - but headache time when you try to reconcile them
spend wrote:With normal engines there seem to be problems keeping the crank located in the block, and even the block stiff enough. I can't see how it could be achieved realistically when you are moving the crank up and down, or am I missing something? . . . :D
The VCR you are talking about is FEV's VCR that displaces the crankshaft to change the compression ratio.
patcrank VCR does not displace the main crankshaft.
Open the http://www.pattakon.com/patcrank/patcrank5.exe animation, at the end of http://www.pattakon.com/patcrankVCR.htm and run it according the instructions.
The main crankshaft rotates on its normal bearings on the crankcase (i.e. it is not displaceable).
The secondary crankshaft (that deals with only 1/20 of the piston load) is the displaceable one.
Is it clear now?
spend wrote:With normal engines there seem to be problems keeping the crank located in the block, and even the block stiff enough. I can't see how it could be achieved realistically when you are moving the crank up and down, or am I missing something? . . .
The VCR you are talking about is FEV's VCR that displaces the crankshaft to change the compression ratio.
patcrank VCR does not displace the main crankshaft.
Open the http://www.pattakon.com/patcrank/patcrank5.exe animation, at the end of http://www.pattakon.com/patcrankVCR.htm and run it according the instructions.
The main crankshaft rotates on its normal bearings on the crankcase (i.e. it is not displaceable).
The secondary crankshaft (that deals with only 1/20 of the piston load) is the displaceable one.
Is it clear now?
The trouble with it all is that its extra mechanisms and extra bearings and all that.... and if there is one thing I have learnt in my time it is that the more complex things are, the more likely they are to break, do what you dont want them to do, cause something else to break etc... Also its very expensive.
Hence why the ferrari variable valve timing (3D cam) never caught on (the less effective but MUCH cheaper and simpler honda VTEC 3 lobe is now the solution developed), why the 5 valve engine never caught on, why desmodromic valves arent wide spread.
[quote="crayefish"]The trouble with it all is that its extra mechanisms and extra bearings and all that.... and if there is one thing I have learnt in my time it is that the more complex things are, the more likely they are to break, do what you dont want them to do, cause something else to break etc... Also its very expensive.[/quote]
Everybody likes simplicity.
Yet, to comply with the new emission regulations, simplicity is not enough.
A 5.0 liter V8 (like Porsche's Cayenne) has to pay some 50 dollars (or 50 pounds?) per day (as a penalty) to enter into London city because of CO2 emissions.
With variable valve actuation and variable compression ratio (which are, indeed, complicated systems) the big powerful engine becomes a green engine too.
According the mayor, Porsche harms the atmosphere of London too much and somebody has to pay for the damage.
The challenge is to make the necessary changes in the most reliable and simple way.
For instance, the two step VTEC of Honda was good at its time, but it is not good any longer. Honda changes to A-VTEC which is a continuoulsy variable valve train. BMW uses, for many year now, the valvetronic (too complicated, yet too good and reliable at medium low revs). Nissan uses in its top models the VVEL, another VVA (which is demi-desmodromic) capable for higher revs than the models it replaces and way greener.
Ferrari's VVA with 3D lobes were never used in mass production because it has many problems yet to solve.
Back to patcrank VCR.
Is the gain worth the pain?
The additional parts "deal" with a tiny part of the piston loads: When the high pressure gas loads the piston with 2.000Kp, only 100Kp load the secondary crankshaft. This 100Kp load is lighter than the loads met in the valve train. I.e. the system has many reason to be reliable.
It is also the complexity: four small light-alloy secondary connecting rods (having some 100 mm centre to centre distance) and a thin and lightweight secondary crankshaft, plus a slow moving control frame.
These for a V8, i.e. 5+1 cheap and lightweight parts.
Compare the patcrank VCR with Nissan's, Daimler's, Honda's multilink VCRs. They need 18 expensive, strong and heavy parts to do less, because they add a lot of weight to reinforce the crankcase and a lot of friction.
Your obviously something to do with this site/company so I wouldnt be too surprised if you get a few skeptical posts. You like to compare patcrank system to other manufacturers, are there any real working engines out there with this system or is it all 3D modelling and animation?
Looking at this it appears to me that the big ends would have to be prohibitively large in order to accommodate the additional secondary crank mechanism.
Also you end up with 2 sets of bearings per journal, one of which is constantly rocking across the same path. Wear is going to be a real issue with that bearing set.
Also not sure how you would assemble this onto a crank unless each of the secondary crank journals were also split.
Well if it is any good then the big engine makers will buy the patent and it will be on in the road in the next 2 or 3 years. (or more likely they will just design around the patent so they dont have to pay a penny)
however i suspect we wont see it on any cars. i am sure some car makers will be putting VCR on some of their engines in the future, but at the end of the day I recon the leaders wont. and by leaders i mean toyota, honda, vw and audi (roughly in that order!)
the big thing now is GDI development
EDIT: oh and turbo/supercharging. also the comprex charger is a biggie (maximum boost at very low revs) if 2 certain companies (no names mentioned ) can sort out the patent problems!
GDI has been around for a good few years now but has never really taken off. It was probably about 10 years ago that Mitsubishi started selling it on their main stream cars. Its a benefit but it doesnt seem to have been a major benefit. Wotlands post seems like a solution that atleast is working although it does seem very complicated and at a guess wear prone.
I think the real question is, how long are manufacturers going to continue to develop the IC engine? It makes sense in the short term but not in the long term.
not without flat diesel heads, very little valve lift and duration and a LOT of detonation! 
just like micro and macro stuff fine whilst you consider just one viewpoint - but headache time when you try to reconcile them 
