Mahle printed pistons for fuel mileage?

[Isaac Zachary]

Mahle is working on making 3d printed pistons right now for Porsche.

The general idea is that the pistons can be made lighter and still retain their strength. This is because it's easier to leave metal where you need it and take it away where you don't (sometimes leaving a honeycomb structure in some areas). Apparently it's easier and cheaper to 3d print this type of piston design than to machine it. The resulting pistons can withstand more heat, force and speed than current forged pistons can. There's also talk of an increase in efficiency.

Probably these pistons won't be cost effective any time soon, but eventually we may be able to just throw a set of these in any engine and increase its efficiency (and power potential).

[freebeard]

Interesting. It sounds like having an oil-cooled top piston ring land is a big part of the design,

Mahle developed the Nikasil electroplated cylinders for Porsche. en.wikipedia.org/wiki/Nikasil

[cRiPpLe_rOoStEr]

I'm aware GE already uses some 3D-printed components in some jet aircraft engines, but it's based on ceramic compounds.

[some_other_dave]

Mahle has done a lot of materials engineering and parts manufacturing for Porsche over the years. A good bit of the tech has also made its way to other brands later.

The benefits I can see for the printed pistons would mostly be the lighter weight, so less energy required to move them up and down. Not a huge effect, I would think, and one that could be approximated by using a lighter wrist-pin or lighter rods.

-soD

[Isaac Zachary]

Originally Posted by some_other_dave

Mahle has done a lot of materials engineering and parts manufacturing for Porsche over the years. A good bit of the tech has also made its way to other brands later.

The benefits I can see for the printed pistons would mostly be the lighter weight, so less energy required to move them up and down. Not a huge effect, I would think, and one that could be approximated by using a lighter wrist-pin or lighter rods.

-soD

But lighter pistons cause less force on the wrist pins and the rods and therefore permit even lighter wrist pins and rods and crankshaft with traditional materials and machining techniques. But if the pistons stay the same then the wrist pins and rods will require exotic materials (like titanium) and/or more intensive machining. It's also important to note that these 3d printed pistons are made with traditional alloys, nothing special.

[freebeard]

They should be able to print cylinders with gyroid infill air or water/oil cooling channels instead of flat slab fins.

all3dp.com/2/cura-gyroid-infill/

Many 3D printing enthusiasts have carried out their own studies and testing, all pointing towards a similar result: Gyroid infill is stronger and has faster printing times than other infill patterns.

It’s been said that this infill pattern was inspired by a 2017 MIT study, where researchers designed one of the strongest and lightest materials available using graphene. The strength of the object was not only due to its material, but also its gyroidal shape. In fact, they found it was the shape that was more responsible for its strength than the material.

[jakobnev]

...but eventually we may be able to just throw a set of these in any engine and increase its efficiency

Wouldn't other moving parts need to shed some weight too to keep the engine balanced?

[Piotrsko]

I thought Mahle custom pistons were lost wax style of casting with machining to tolerance. So no great leap to sinter cast them then machine and I can see where they can be made thinner that the lost wax process.

With lighter pistons, you just remove metal from the rotating mass counterweights, NBD.

[Isaac Zachary]

Originally Posted by jakobnev

Wouldn't other moving parts need to shed some weight too to keep the engine balanced?

Pistons are usually balanced by other pistons, at least in 4, 6 and 8 cylinder engines. Usually one piston goes up and another goes down at the same time canceling each other out. This is why you're supposed to try to keep all your pistons the same weight. I put my pistons on a scale accurate to the tenth of a gram when rebuilding. And some sets are much heavier or lighter than other sets already, with no change in engine balance in the end.

But depending on the engine yes, this could be true. Any engine that has an inherent primary imbalance, like a 3 cylinder engine, will usually have some sort of weights on the flywheel and pulley to counteract the imbalance. But you wouldn't have to lighten everything in the engine to restore balance. You'd just have to take off a little at those weights.

Originally Posted by Piotrsko

I thought Mahle custom pistons were lost wax style of casting with machining to tolerance. So no great leap to sinter cast them then machine and I can see where they can be made thinner that the lost wax process.

With lighter pistons, you just remove metal from the rotating mass counterweights, NBD.

3D printed pistons are still in the test phase. Apparently this can make then significantly lighter than other methods like with the gyroid design freebeard mentioned.

[hayden55]

Don't forget about counter balance shafts and those big counter weights they have on most crankshafts to balance out those heavy punchers. I imagine with this they would hardly need any.