Shock storing conrod arm mod

[freebeard]

I just like the idea of regression testing—trying every combination to see what breaks what, in SoCal in mid-century.

Imposing a delay between the compression and power stroke suggests my favorite My Little Unicorn, the Scuderi Split-cycle engine.


https://en.wikipedia.org/wiki/Scuderi_engine

They foundered on trying to engineer their own proprietary inline-4 test engine. The patent lock dates to August 2011, until then you could build a reasonable test engine using a VW boxer four, half a big-bore kit, and a re-indexed roller bearing crankshaft. It would require the later dual-port heads and a 5-gallon air tank. All existing parts.

They can't hide the IP. It's the offset in degrees between the two cylinder banks.

[niky]

Originally Posted by cajunfj40

A simpler way of getting more leverage at peak cylinder pressure/TDC is offsetting the piston bore relative to the crankshaft, or offsetting the wrist pin in the piston. Basically, when the piston is at TDC, the crankshaft is rotated a bit beyond the point where the crank arm would be vertical. When peak cylinder pressure occurs, it will be working on a lever arm right away, rather than pushing straight down the vertical stack of piston/wrist pin/conrod/crank bearing/main bearing/main bearing cap, and trying to squeeze the oil films between those parts.

Some motorcycle engines do this. And Nissan's new variable compression engine has the offset built into its geometry. Pretty neat bit of kit, that thing... a very simple and elegant way to get variable compression... and manages to minimize forces on the pistons to the extent that they claim to use much lighter conrods than normal engines.

[freebeard]

Originally Posted by Permalink #34

What is to be gained over offsetting the wrist pin in the piston??

That mention didn't gain any traction, so I escalated to the Scuderi.

[Ecky]

Originally Posted by niky

Some motorcycle engines do this. And Nissan's new variable compression engine has the offset built into its geometry. Pretty neat bit of kit, that thing... a very simple and elegant way to get variable compression... and manages to minimize forces on the pistons to the extent that they claim to use much lighter conrods than normal engines.

The first gen Insight's engine does this.

[DieselJan]

Originally Posted by craysus

CSRV vs. Poppet Valve - Coates International Ltd.

Using a cammed intake system similar to above, and taking changing the profile based on simple rotation. You could imagine taking this to the next phase, and implementing a Wankel style interface as the cam, instead of the twin cams used byu coates...and therefore simplifying the movement down even further..

Alternatively, electrically controlled "valves" could be utilised on a more conventional head...and if the valves opened / shut normally, but could be extended INTO the cylinder, to increase compression at the desired part of each scycle..(Making the valves a solid tube to take up volume..maybe twisting open / closed to vary between a solid tube and a fuel delivery / exit path)

Just some random thoughts to help with overcoming the requirement for 4 x truck springs being inside a 4" cylinder bore.. (Havent invented a Tardus as yet...sorry..)...

Very interesting link. Looks like a workable improvement.
Also great idea from you, I think? Increase compression ratio after TDC with the valves to burn fuel better and get more power to wheels.

Hi Cajunfj40
I love Ecomodder and mean no harm. I know it is difficult to have threads that doesn't drift, just had a suggestion. Things like in the link above IMHO will bring the gains I'm hoping for. After that type of mechanical changes we can start improving with electronics, etc.

[cajunfj40]

Hello craysus,

CSRV vs. Poppet Valve - Coates International Ltd.

Using a cammed intake system similar to above, and taking changing the profile based on simple rotation. You could imagine taking this to the next phase, and implementing a Wankel style interface as the cam, instead of the twin cams used byu coates...and therefore simplifying the movement down even further..

Ooh, Coates! Nice rotary valve idea. Thought I'd seen some other arrangement of that before, here's a good article on the problems with rotary valves in general, and many attempts to get around them:
Rotary-Valve Internal Combustion Engines - way2speed I think the "Aspin" is the most similar to the one I saw.

Alternatively, electrically controlled "valves" could be utilised on a more conventional head...and if the valves opened / shut normally, but could be extended INTO the cylinder, to increase compression at the desired part of each scycle..(Making the valves a solid tube to take up volume..maybe twisting open / closed to vary between a solid tube and a fuel delivery / exit path)

There've been many attempts at solenoid-controlled valves. Some successful, most not so. I think the main problem was power consumption for direct electric solenoid control. Hmm, here's a Jalopnik article on a Koenigsegg Freevalve equipped Saab. What It's Like To Ride In A Car With The Camless Engine Of The Future Pneumatically actuated valves, so the electronics control the pneumatics, greatly reducing the power consumption of the solenoids, and pushing it off onto an air compressor instead. The article's low on tech, but hits the advantages pretty well. Freevalve has a website, too. FreeValve | Setting Engines Free I like the idea - I wonder how well it stacks up vs. cam phasers and other VVT designs from a cost/reliability standpoint.

Hello freebeard,

Quote:
Originally Posted by Permalink #34
What is to be gained over offsetting the wrist pin in the piston??
That mention didn't gain any traction, so I escalated to the Scuderi.

I poked around a bit and found the nice diagram in this article: https://rideapart.com/articles/free-...ders-explained It's for offset cylinders WRT the crank, but offsetting the wrist pin gets a similar effect.

Wrist pin offset on production engines is primarily about reducing piston slap, but can also be used to change the power output of an engine. This article Chevy Big-Block Performance: Displacement Decisions has some info about halfway down. Note the caveats in the article - the effect is small and it takes experimentation to get the right offset. Increased power from the same amount of fuel is an efficiency increase.

Hello DieselJan,

Hi Cajunfj40
I love Ecomodder and mean no harm. I know it is difficult to have threads that doesn't drift, just had a suggestion. Things like in the link above IMHO will bring the gains I'm hoping for. After that type of mechanical changes we can start improving with electronics, etc.

No worries, I didn't think you meant any harm. I'd have been sharper in my response if I did. As for mechanical vs. electronic, as much as I enjoy wrenching I can't justify sinking a lot of cash into an ICE anymore. Swapping in a junkyard-sourced modern turbo DOHC I-4 in place of my cam-in-block NA V6 is rather pricey. A custom or low-production prototype engine is likely to be even pricier. The cost seems comparable to a low-range EV conversion plus a small genset or pusher trailer for the few days a month I need to drive further and can't just borrow the family minivan or my MIL's truck.

[freebeard]

As for mechanical vs. electronic, as much as I enjoy wrenching I can't justify sinking a lot of cash into an ICE anymore. Swapping in a junkyard-sourced modern turbo DOHC I-4 in place of my cam-in-block NA V6 is rather pricey.

If you pick up the Paul and Sabrina's AC controller thread at:
http://ecomodder.com/forum/showthrea...tml#post536349
HaroldinCR introduces himself and the concept of using a 20hp water-cooled polyphase DC alternator from a Buick Lacrosse hybrid for EV motorcycle conversions. He may spin off a separate thread.

I'm seriously considering abandoning the pure EV conversion using a Lexus MGR and all the headaches of Toyota axle stubs and VW axles, etc. The alternator is about 8" in diameter and 8" long with another 8" of electrical junction box extending off the back.

This makes a mild hybrid with stop/start and regen very possible, with a 115VDC battery pack, compared to the HSG's 250-400VDC. Comparable to a turbo and engine management swap in complexity.

[cRiPpLe_rOoStEr]

Originally Posted by cajunfj40

Nice rotary valve idea.

When it comes to rotary valves, the first thing that comes across my mind are some ancient aircraft engines that resorted to sleeve-valves before tetraethyl lead became mainstream as an anti-knocking additive to gasoline.

[Fingie]

good 'ol sleevies, lol



it's not certainly a simple system

[freebeard]

http://ecomodder.com/forum/showthrea...r-35003-2.html