Interesting study on heat loss
 

Green Car Congress: Toyota: targeted cooling of upper cylinder liner effective way to improve anti-knock quality and thermal efficiency

regards
Mech

So in a practical future engine design, this could be as simple as a second cooling circuit and a higher compression ratio?

Pretty interseting. Maybe they should create cylinder liners which are ultra thing - like a silicon nickel composite plama arced onto aluminum liners.

They could call the resulting technology SiliNic.......

(GRins!)

2 stroke guys figured this all out 30 years ago and use chrome type plating called nicasil. Theory is the plating is on a aluminum, which is a great conductor of heat.

I think Oldsmobile used the NickaSil on their 215 cube turbocharged V8 in 1963. Later GM licensed the technology to Mercedes, Porsche, and other manufacturers including Rover.

It was 215 pounds, neat engine, 1 HP per pound.

Forget boring that block over standard.

regards
Mech

Nicasil was developed by Mahle in Germany at the request of Mercedes Benz for the experimental Wankel engine MB were using as a prototype at the time.
When the company decided rotary engines were not the way to go they allowed other companies to access the patent.

Subsequently it was used by Porsche on their air cooled competition engines including the 917 Turbo installation to help with the 1000+ horsepower output.

When the patent expired a large number of companies bought the technology to use in virtually all two stroke engines from chainsaws to world champion motorcycles.

So far as I know GM never used it.

Peter.

BMW tried nikasil ... bad idea
 

...with the recent switch to ultra-low suphur gasoline (and diesel) fuels, GM and others are giving Nikasil another "try."

there are other solutions similar to nikasil which don't have issues with sulphur gas - I don't know the exact name. This technology is a mature one for the 2 stroke crowd.

I didn't realize Mahle had invented it that long ago. I do know 911 porsche's have had it for a long time.

Even Briggs & Stratton has had nikasil on their cheapo-line of engines for 54 years. I hate the stuff; you can bore out/hone good ol' cast iron. Premium small engines have cast iron liners, among other things.

This article (about Toyota's not exactly original 'discoveries') sets me thinking along the lines of my old soapbox gripe - the oft overlooked point about engineering to spread the load of waste heat around (in time) rather than always engineering blindly for the worst-case scenario instantaneous peaks of thermal load.

In a gas turbine engine for example, because of the continuous flow of heat across the combustion zone, waste heat exhausted after the turbine stage can be recuperated by passing the hot gases through a heat-exchanger that heats the air just after the final compression stage.

If there was a process by which the hottest region of the cylinder wall (nearest to the exhaust valves) could regenerate its excess heat around onto the surfaces nearest the inlet valves then (if it could happen fast enough [using heatpipe tech?]) there would be an opportunity for a kind of micro-recuperation in a SI engine. The whole system would need to be designed from the ground up for this to be possible and the intake tract would need to be thermally separated from the head otherwise the thermal efficiency would be lowered by too warm air (esp. on DI gas engines).