Ricardo on sources of engine friction

[Shannow]

Sir Harry Ricardo is one of my heros, and Ricardo do lots of work on analysis and modelling, design, blah blah...here's a preso on sources of engine friction, with some scalars and measurement confirmation.

http://www.ricardo.com/Documents/Downloa...anceEngines.pdf

Check out the piston on page 16...15k RPMs ?

 

[Shannow]

Oh, and be careful of the charts that are in MEP (Mean Effective Pressure).

The Mean Effective Pressure is the "average" pressure, which has to be multiplied by volume and speed to give horsepower consumed by that factor.

e.g. while bearing friction looks flat in IMEP, it means that power consumption increases linearly (and a little bit) with speed. A "wedge" like crankshaft windage means that it's exponential with speed

 

[d00df00d]

Thanks for posting this, Shannow!

 

[Kira]

Hello, Talk about a detailed examination! Thanks

 

[yvon_la]

one thing is sure,xw20 is too low viscosity In lot of area,if you do only or mostly city driving ,xw20 is fine but if you do more xw30 is better suited,the issue is the flow of oil or whatever cannot keep up with lubrication demand of engine,its like as rpm goes up the pressure goes up, but only in serie !but the demand of the engine is in parallele(oil wise) .for the demand to be met engine would likely need additional oil pump !with more oil supply,then the engine is likely not starve for oil ,even tho rpm rise mean part need more oil .basicly oil cannot keep up!

 

[loyd]

I find it interesting that he didn't explore the friction added by the rocking of the slipper-skirt pistons on the test engine.

 

[MolaKule]

In the conclusions it speaks to asperities during run-in and post run-in wear data as possible feedback data to improve simulation results.

I am thinking that radioisotope tracer results could be incorporated into the model to improve simulation results from "new-build" to X-miles of running.

 

[MolaKule]

Originally Posted By: loyd
I find it interesting that he didn't explore the friction added by the rocking of the slipper-skirt pistons on the test engine.


It's possible it is included in the results of slide 42.

Recall that simulation is a set of mathematical models incorporated into a suite of Finite Element Analysis (FEA) alogorithms, and it is only as good as the data inputted, the assumptions, and the current knowledge of what we think happens.

 

[yvon_la]

http://www.webelements.com/magnesium/physics.html
this might be an interesting site to help whats what!never mind the magnesium part,it contain a lot of what is used in oil today ,yes sadly some are missing but most are there

question:is thermal stability size important at the size we have in oil,if it is you might want to look at the magnesium and calcium.there is a huge difference(this is probably why magnesium wear so slow,it is more size stable at different temraturealso on par with molybdenum in lot of area!i wonder why oil maker bother adding molybdenum and zinc.