Cardan gear vs. slider crank in IC engines

[unclematt]

https://oa.doria.fi/bitstream/handle/10024/36120/isbn9789522145345.pdf

This paper compares the slider crank to the Cardan gear when used in internal combustion engines and was written just last year. The conclusion states that a cardan gear setup in IC engines would be superior to that of cranks sliders, which are almost universally used now. Considering the benefits offered by a hypocycloidal system, such as no side forces on the piston (less friction), closer possible tolerances between cylinder and pistion, less energy lost to blowdown, and longer stroke, this thread is devoted to any thoughts or ideas you may have on the subject.

Please check out the paper linked above to see all about this design if you are not familiar with it already.

I have especially been thinking about a "rollerized" cardan gear design using silicon nitride roller bearings to handle the loads and operating environment. This would also reduce the need for lubrication dramatically. I have also been thinking about using this design in a diesel engine. I am trying to evaluate and quantify the of forces the silicon nitride bearings would have to endure. Can anyone give me an idea of the forces that a connecting rod bearing experiences in a normal diesel engine? Both peak and continuous?

This will help me formulate an approach to deciding on the crank journal element diameter if a roller bearing was used instead of an oiled sleeve bearing. In other words, at the connecting rod, I'm trying to figure out the minimum practical inner diameter of the roller bearing given the use of silicon nitride bearings. Any help would be appreciated.

 

[TDIMeister]

Replacing the main- and con rod big-end bearings with rolling element bearings is nothing new. Aside from its nearly ubiquitous application for small two-stroke engines, there has been also examples of large Diesel engines in history using roller bearings, and more recently companies like FEV and Schaeffler have published papers on improved fuel consumption through reduced engine friction.

e.g. Pleus et al.; Driving the Powertrain towards CO2 Reduction, FISITA paper F2008-06-225 2008

Tiemann et al.; Roller-Bearings in Combustion Engines –
an Effective Way for Fuel Saving, 14. Aachener Kolloquium Fahrzeug- und Motorentechnik 2005

Solfrank et al.; Opportunities for Reducing CO2 Emission by Using Rolling Bearings in Engines, MTZ 07-08|2008

Tiemann et al.; A Cost Effective Way to Reduce Fuel Consumption The Roller Bearing Engine, MTZ 04|2007

In of these studies, long-term durability and load capacities were in fact NOT the main problems, but rather matching the roller bearings' NVH performance of that of the status quo plain bearings.

 

[thundair]

The first triple slipper bearing I have seen was a Bourke engine. It was 2.5"dia X 3" lg

I use ceramic bearings to update PSRU's mainly for heat reduction, as the bearing was right sized the first time.
But I have never seen a ceramic needle bearing. I wonder hmmmm......

I don't know anything but the people that do.

 

[unclematt]

Thank you.