50% oil savings! 15% friction savings! by Ronco

Since the job of the oil scraper ring directly impacts oil consumption, I would tend to agree with the first part of their statement.

However, with the exception of a 2000 GMC Sierra pickup with the Vortec "Like A Knock" 5.3 V8, I have never had a new vehicle since 1990 consume oil, even during break-in. A motor that burns oil will quickly foul the O2 sensors and catalytic converters

Proper oil selection is even more important with zero-gap and two piece rings. A poor quality oil that causes ring land fill deposits will quickly allow the rings to stick, resulting in blowby and oil consumption.

There is no magic elixir for that problem. Once the ring land is filled, the only solution is a rebuild

 

The statement says the rings are for direct injection engines. The current and all past Prius engines are/were not direct injection. The new ring design is non-applicable.

 

As far as gaining efficiency, the next step is the same being used by the Prime Mover engine makers like Wartsila or Waukesha: per cylinder spark, fuel, and valve control

Waukesha is still trying to find a good ring design that lowers friction, but lasts the +30,000 hours before overhaul. That has been a hard engineering challenge, usually results in oil consumption

 

I would say in the prius the friction savings aren't likely to amount to much. I doubt they would in any car, its a press release.

The next obvious step for efficiency is DI. This could be used to either increase hp, or decrease engine size which could reduce friction. Different materials for rings could help but its not the low hanging fruit. Going with a turbo DI small 3 cylinder would likely improve efficiency the most, but with higher cost, complexity, and likely worse NVH.

A small amount of oil consumption is not necessarily a bad thing, its part of engineering trade offs. A lower friction ring set that causes more overhauls is a bad trade off though How much fuel will that mechanic need to get to work to overhaul your slightly more efficient vehicle.

 

This part has me puzzled:

All the engines I've worked on use a 3 piece oil ring. I wonder what they are talking about.

-mort

 

Unfortunately -any- oil "consumption" will result in shortened cat life. This is legislative territory!

In the late 1970s a few motorcycle manufacturers were working on cylinder linings to lower friction (the actual purpose was to increase heat transport for very high output 2-stroke engines - by running on or close to the aluminum "block"). I'm sure we've all heard of or even seen the chrome coatings, which tended to be easily damaged and then pealed off. One manufacturer was trying a nitride coating (sputtered on) that was a dry lubricant as well. Never heard why it didn't succeed in the marketplace.

 

Thanks, I thought the cats could handle a little oil, but I had no idea how little that is.

I've helped design machines for making disk drives. We have been able to apply very thin films of lubricant to the disk surface. The problem with these lubricants for engines is they would not stand up to the heat. Someone is going to come up with a good lubricant coating to the cylinder walls.

 

As far as piston ring design, consider this carefully monitored engine dyno test of Childs and Albert ZGTF (Zero Gap Tapered Face) rings

Childs & Albert's Zero-Gap Second Ring - Test, Review - Hot Rod

The cost for a typical small block is twice that of a regular ring set

As far as coatings, moly coatings have been around for a long time now

 

Does the 50% oil savings & 15% friction savings improve with this?


.

 

Thanks. That is a better improvement than I would have thought. The link mentioned cost, but from your OP I would think durability would be the bigger problem.