Topic: Diesel dual crank twin

[Blackhorse]

It would be interesting to see this stuffed into a cafe racer frame.

http://www.neander-motorcycles.com/shortversion-neu/main_en.html

[Retro Rocket]

WOW thats a very interesting read..

Mick

[hoodellyhoo]

So is the only reason for dual cranks the vibration? I guess I don't see what the advantages are. Still pretty neat though.

[kenolds]

Wierd!  Looks like the angle between the connecting rods and the piston travel is REALLY large on the power stroke. Doesn't seem like it would be very efficient.
 It is cool, though how the two wrist pins keep the pistons level in the bores.  I guess that allows them to have very short skirts.  I will be interested to see their efficiency numbers. - I'm certain they are lower than a typical single crank shaft turbo diesel.  From their website, it seem they just want to do something different and are trying to find ways to justify it.  Hasn't Yanmar been making small diesel engines for many years?  Do they vibrate too much to use on a motorcycle?  I doubt it.
Many engines already use a counterbalance shaft- both diesel and some gasoline 4-cylinders.  I don't know - maybe they have invented the next great engine design - or maybe something akin to the Wankel engine - cool , but not really better.

Kenolds

[mlinder]

Specs say 112hp/144lbft out of 1.34 litres, turbo'd.

[bucky katt]

thats well over double what a 1340cc harley evolution motor makes stock. i want one, looks like it might go good into my cb500t frame. the design looks almost like the ariel square four motor with just the front cylinder but still keeping both cranks. what a torque monster

[kslrr]

Not only do the dual cranks decrease vibration, it allows much more torque to be applied during the power stroke.

[mlinder]

thats well over double what a 1340cc harley evolution motor makes stock. i want one, looks like it might go good into my cb500t frame. the design looks almost like the ariel square four motor with just the front cylinder but still keeping both cranks. what a torque monster

But it's not anywhere near what a 1300cc normally aspirated Suzuki  makes in terms of horsepower, and the Suzi comes within 2/3rds of the torque of that engine.

A supered / turbod Suzi engine would absolutely decimate that thing in terms of both low end, and top end power. I'm betting if some cams were made for more low end on the suzi, it could easily have more low end, even normally aspirated.

[noexit]

Wierd!  Looks like the angle between the connecting rods and the piston travel is REALLY large on the power stroke. Doesn't seem like it would be very efficient.

That's what I thought initially, but does it say which direction it spins? I don't know if there'd be a net benefit either way though.

And actually, there's no more travel on any part of the stroke than a normal engine. If you pretend that one crank isn't there, the travel is the same except for the exaggerated unevenness of lateral forces on the piston. Add the second crank into the equation, and you've taken out lateral forces all together, eliminating one source of friction based inefficiency a conventional engine has, and adding the friction of another set of bearings on another crank.

So thinking through all the sources of friction and rotational mass involved leads me to conclude that I'd need a degree in engineering (I wish!) and some math (yeah right) to figure out how well that design would work.

[mlinder]

Wierd!  Looks like the angle between the connecting rods and the piston travel is REALLY large on the power stroke. Doesn't seem like it would be very efficient.

That's what I thought initially, but does it say which direction it spins? I don't know if there'd be a net benefit either way though.

And actually, there's no more travel on any part of the stroke than a normal engine. If you pretend that one crank isn't there, the travel is the same except for the exaggerated unevenness of lateral forces on the piston. Add the second crank into the equation, and you've taken out lateral forces all together, eliminating one source of friction based inefficiency a conventional engine has, and adding the friction of another set of bearings on another crank.

So thinking through all the sources of friction and rotational mass involved leads me to conclude that I'd need a degree in engineering (I wish!) and some math (yeah right) to figure out how well that design would work.

Yep, my guess is the power stroke is with the big ends of the rods at the inside, meaning the left crank spins clockwise, the right counter-clockwise. Interesting design, and I can think of a few advantages to some of the features involved.

[crazypj]

thats well over double what a 1340cc harley evolution motor makes stock. i want one, looks like it might go good into my cb500t frame. the design looks almost like the ariel square four motor with just the front cylinder but still keeping both cranks. what a torque monster

But it's not anywhere near what a 1300cc normally aspirated Suzuki  makes in terms of horsepower, and the Suzi comes within 2/3rds of the torque of that engine.

A supered / turbod Suzi engine would absolutely decimate that thing in terms of both low end, and top end power. I'm betting if some cams were made for more low end on the suzi, it could easily have more low end, even normally aspirated.

 Yeah, but it's a diesel 
 look at the rpm,144ft/lbs @2,600.
 No inline 4 can get even close to that at low rpm, Busa doesn't do 'much' (relative term  ) until 6,000+
 I bet its difficult to get than much torque on the road without wheelspin?

PJ

[mlinder]

thats well over double what a 1340cc harley evolution motor makes stock. i want one, looks like it might go good into my cb500t frame. the design looks almost like the ariel square four motor with just the front cylinder but still keeping both cranks. what a torque monster

But it's not anywhere near what a 1300cc normally aspirated Suzuki  makes in terms of horsepower, and the Suzi comes within 2/3rds of the torque of that engine.

A supered / turbod Suzi engine would absolutely decimate that thing in terms of both low end, and top end power. I'm betting if some cams were made for more low end on the suzi, it could easily have more low end, even normally aspirated.

 Yeah, but it's a diesel 
 look at the rpm,144ft/lbs @2,600.
 No inline 4 can get even close to that at low rpm, Busa doesn't do 'much' (relative term  ) until 6,000+
 I bet its difficult to get than much torque on the road without wheelspin?

PJ

It's all relative, PJ. Does the diesel reach 2600 rpm from 1 grand faster than the busa reaches 6 grand from 2000? If not, it's a moot point.

[Retro Rocket]

I don't think comparing Diesel engines with petrol engines works at all and i doubt the manufacturers cared one iota about it either. This engine should have way better "gas" mileage and would be a ball to ride on the street with torque figures like that....

Mick

[kenolds]

Somewhere on their site is a little animated model of the engine that shows the compression stroke with the rods to the center.  Yes, comparing diesel engines to gasoline engines is hard to do on paper.  It all boils down to how it feels when you ride it.  I would like to test ride one.  I bet the instant torque is fun for cruising, but not best for all-out racing.  If for no other reason than it would be much heavier than an equally powered gasoline engine.  By the way, the latest winning design race cars in the ALMS series are diesels.  They sound pretty wierd at the track.

Kenolds