I found this interesting. Perhaps there is much room for improvement for the ICE.
Last edited:
Dimpled Pistons? Available today for some engines.
- Thread starter WobblyElvis
- Start date
Not likely to be worthwhile. The additional surface area increases heat transfer and reduces efficiency.
When will people just say their messages and skip trying to be a TV show?
"Wow, 3 mpg improvement over 16 mpg....that's like 25%." sigh
We finally saw the 'miracle piston' @ 14:20; please.
The salesman/rep said each dimple pattern is unique to each engine. Forgive me for not believing him.
How much of this touted improvement is caused by the improved rings?
"Wow, 3 mpg improvement over 16 mpg....that's like 25%." sigh
We finally saw the 'miracle piston' @ 14:20; please.
The salesman/rep said each dimple pattern is unique to each engine. Forgive me for not believing him.
How much of this touted improvement is caused by the improved rings?
The claims on efficiency improvement are quite high.
Almost unbelievably high
I like the ideas. The improvements may have more to do with the shape of the middle chamber than those little dimples around the outsides.
I’d trust Volvo.
www.volvogroup.com
Technology award for wave piston design that lowers fuel consumption
The Volvo Group’s new truck engines are more fuel efficient as a result of their intelligent piston design. Waves have been added to the piston crown to improve the use of oxygen. The engineers behind the innovation have now received the Volvo Technology Award 2017.
We used to do that to snowmobile racing pistons back in the 1970's, I don't know if it made a difference or not.
That design has merit. As it produces specific flow patterns.I’d trust Volvo.
Technology award for wave piston design that lowers fuel consumption
The Volvo Group’s new truck engines are more fuel efficient as a result of their intelligent piston design. Waves have been added to the piston crown to improve the use of oxygen. The engineers behind the innovation have now received the Volvo Technology Award 2017.
This isn't a new thing. Dimpling has been around for decades. I know of 2 engines that tried it in the last 10 or so years. One of them just had a slight power loss across the rpm range. The other had a massive power loss from detonation. The dimpling in the quench area of the piston was trapping air and fuel and becoming essentially a small combustion chamber. If it made any sort of difference, it would already be commonplace in professional racing engines. There's a reason it's not. Every few years, this comes back into the spotlight. Somebody gets an itch to try it out as if they're pioneering something only to go silent when they come to the same conclusion as many before them.
That's what I though too. The only reason for dimpling is to mandate where the combustion will be. In a spark ignition engine it makes no sense other than a central one to guide the ignition timing etc. Mazda did that with SkyactivG and X. The all over the place dimples doesn't do jack and if they say everyone is unique stay the heck away. The last thing you want in engineering and manufacturing is "everyone is unique".
I remember getting "pop-up" pistons for my 1965 Mustang with 289 engine. Are dimpled same as pop-up?
No. The term "pop-up pistons" refers to dome pistons. The piston has a plateau raised above the piston crown to reduce chamber volume thus increasing the compression ratio. The 289 has a short stroke which limits how much volume can be compressed. (given all other variables are equal) To counter this, you either have to reduce the head's chamber volume or put a "pop-up" on the piston to achieve a higher compression ratio. The later is the easiest and most common way to do that. Reducing chamber volume is a big can of worms as doing such effects valve shrouding, flame propagation, turbulent flame speed, squish direction, etc...
I try to avoid dome pistons as the dome acts as an obstacle to flame propagation, slowing down the flame speed, and thus reducing efficiency. It can also become a hot spot for detonation.
I did it at 17 years old not knowing a whole lot about engines. But yes to increase compression ratio.
If the dimples did anything, every car manufacturers would be using it.
OEMs already use optimal shapes to concentrate the fuel around the spark plug.
OEMs already use optimal shapes to concentrate the fuel around the spark plug.
AH, the Honda VR!
Honda Global | The Oval Piston Engine / 1979
Honda Motor Co.,Ltd. Honda Global Site - Visit the official Honda global web site and find episodes about Honda's unique oval piston engine.
global.honda
NR 500 and NR 750 used these.
I…. Don’t understand. What is this beast of a cylinder-boring and ring tension catastrophe?
