GregAx Posted 6May, 2015 Report Share Posted 6May, 2015 http://www.enginelabs.com/news/porsche-working-on-variable-compression-connecting-rod/ Link to comment Share on other sites More sharing options...
Peter M Posted 6May, 2015 Report Share Posted 6May, 2015 Reckon it's a phony. Why, when you could use variable valve timing and lift to do the same and much simpler with no disadvantage from increased reciprocating mass, similar to decompression setups and cylinder deactivation used for decades. How would the control solenoid be activated? Would a Porsche subsidiary really submit hand drawings for a patent? Smells of a re-treaded 1st of April prank to me.... Link to comment Share on other sites More sharing options...
tazzieman Posted 6May, 2015 Report Share Posted 6May, 2015 Patents going back to at least '91 Here's a lapsed one , plus the citations at the end http://www.google.com/patents/US7891334 Link to comment Share on other sites More sharing options...
Peter M Posted 6May, 2015 Report Share Posted 6May, 2015 True, there has been much work on the topic but little have demonstrated a real benefit with the Miller Cycle probably the closest to the mark. Again using valve timing to manage compression but with the benefits of a longer combustion stroke. Still think the original proposal is the work of someone with alfoil wrapped around their head and peanut butter in their undies. Link to comment Share on other sites More sharing options...
tazzieman Posted 6May, 2015 Report Share Posted 6May, 2015 Still think the original proposal is the work of someone with alfoil wrapped around their head and peanut butter in their undies. Surely you jest , George? Link to comment Share on other sites More sharing options...
Peter M Posted 6May, 2015 Report Share Posted 6May, 2015 No jest! Just saying there are better ways to go about it. Maybe the peanut butter suggestion was a little harsh. Link to comment Share on other sites More sharing options...
StevepGT3 Posted 6May, 2015 Report Share Posted 6May, 2015 Titanium 991 gt3 rods had a hard and sometimes unsuccessful time holding together with no moving parts at 9000rpm , that contraption looks like a total recipe for disaster in a high revving application Link to comment Share on other sites More sharing options...
tazzieman Posted 6May, 2015 Report Share Posted 6May, 2015 People love to experiment don't they? Human head transplants coming up next. Hasn't the internal combustion engine reached its use by date? Oh wait , America has discovered the world still has plenty of oil. Those frackin' engineers! Link to comment Share on other sites More sharing options...
Pauly Posted 7May, 2015 Report Share Posted 7May, 2015 variable valve lift and variable cam timing works great. having 2 little pistons on a rod like that, i don't see it holding up to power levels performance cars see. I wouldn't use it on my car. I just see it failing and sending a rod though the block. The way we're going with direct injection and quench with the piston & head, running 9.5:1 compression ratios on boosted application is normal these days. The only issue is peak cylinder pressures from high compression and boost applications can kill engines. Link to comment Share on other sites More sharing options...
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