Apparently 'over swirling' is possible as it encourages more gas to be cooled from the chamber sides and reduces the burn quality.The VW swirl chamber is based on a Ricardo patent AFAIK from at least 60 years ago and in the 50's was regarded as one of the best of the IDI's efficiency wise.Surely what makes an engine do work, is not the flames from the fuel but it is just a matter of heat... Extra heat expanding a particular volume of air. So arguably an infra red lightbulb could do the same thing.Initially I couldn't see how the swirl chamber could heat the air; but I guess it can whilst air is cooler than the chamber. But what is the temp of the chamber walls? what with the coolant trying to suck the heat out. Heat will of course go back out of the air as the compressing takes it beyond wall temp on its way up to 600 deg C. Fuel burning only raises it up another 300 deg C or so, Where did the rapidly cooling walls get their heat from? Obviously it came from the previous 4 strokes or at least the power stroke. Thus in the continual process the present power stroke will be 'robbed' of heat for the next cycle. Ceramic coating will reduce heat loss so the same coolant will be able to remove more of the heat that does pass (2/3 of non ceramic setup) and so there will be less heat returning to the air from the chamber walls but with a 1/3 more heat staying in the chamber that doesn't seem a problem. If peak air temp in the chamber is higher in the ceramic case then turning the fuel down should result in similar temperatures to original setup.Reducing radiator size could help; or using pure antifreeze (which although it boils at a higher temperature actually has a lower SHC than water).I don't like the idea of higher and higher injection pressures just seems like extra energy wasted and extra strain on the pump. Neccesary perhaps for absolute power but for economy not required. Somewhere I have a book that suggests that over atomisation can lead to poor burning. Perhaps its linked to times of lower injection volume where the droplets can get lost in the excess of air and slow the flame front...However efficient these TDI engines appear; I'm not getting the vibes that they will be long life engines.,,, Rant off
Anyhow that's an aside a little, there is NO WAY in any circumstances that the pre-cup walls can heat the air. Energy ALWAYS travels from Hot > Cold, thus the colder walls will always warm up by heat removed from the air inside.
I don't know that we have much choice in metals as it not only has to withstand heat, but also be very oxidation resistant at high temps.
Why not? What if the pre-cup walls are(just a guess)350 degrees? They will add heat to the air UNTIL it exceeds that temperature. Now I will admit that won't be for long, but it does add some heat.
Pre ignition chamber is acting as an averaging mechanism reducing the peak temp and also raising the bottom temp. Is this a good thing or is it just a benefit in extremes of outside temperature?Black Ceramic anyone :mrgreen:
I accept that may be possible. May I ask where this heat comes from though? Surely this is a case of heating up your boiler to then pour some hot water on the outside of the boiler, claiming it helps the boiler efficency by heating the boiler up? Insulating the boiler and keeping the heat in the water inside it would result in a far more efficient system.
Bottom line is a hot engine means part of the fuel is uesd to heat the engine up, the more power and more fuel economy for a given amount of fuel can only come from reducing the amount of energy lost via heat to the engine and through the exhaust. I'm promoting the theory here, how efficient a partial coat would be (ie can one measure the improvement) is another matter! I guess a whole ceramic pre-chamber or similar would be the best way to go, coupled with a ceramic 'topped' piston and ceramic coated everything else. Cylinder bore would be a difficult one, easy to coat but problems with life/rings bedding in etc.
Topic: Ceramic Coating (Read 27754 times)
