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New Piston Ring for Gasoline Direct-Injection Engines Reduces Friction By Up to 15% and Oil Consumption By Up to 50%

The LKZ oil control ring, unlike conventional or standard oil rings, combines a stepped surface and taper on its contacting edge, or “land,” and reduces oil consumption by up to 50% and friction by up to 15%. Click to enlarge.

Federal-Mogul Corporation has introduced a two-piece oil ring design for gasoline direct-injection engines, previously developed for diesel applications. The patented LKZ oil control ring reduces oil consumption by up to 50% and friction by up to 15%, compared to the best conventional two-piece oil rings, according to the company. The additional benefits of this improved engine performance are fuel economy, CO2 reduction and longer oil life.

Typical piston rings apply equal pressure to the cylinder bore on the downstroke, toward the crankcase, and on the upstroke, toward the combustion chamber. Federal-Mogul’s LKZ ring combines a stepped surface and taper on its contacting edge, which provides a well-defined pressure to the cylinder wall on the downstroke and a significantly lesser effect on the upstroke.

The downstroke pressure more effectively returns the oil that lubricates the cylinder to the oil pan, as opposed to allowing oil to enter the combustion chamber where it may create carbon on the spark plug or on the cylinder head and increase oil consumption.

The LKZ ring is so effective in pulling oil away from the combustion chamber and in reducing oil consumption that we are able to improve ring tension and reduce friction. Reduced ring friction requires less energy, which means better fuel economy and less CO2 emissions.

The LKZ ring, unlike conventional oil rings, also provides consistent low oil consumption over the life of the engine by reducing carbon build-up on critical parts of the piston, such as just above the compression ring. Carbon build-up on the piston can lead to cylinder liner damage and increased oil consumption. The LKZ ring helps to mitigate that concern for vehicle manufacturers and consumers.

—Johannes Esser, Federal-Mogul’s director of engineering, Rings and Liners

LKZ rings are one of several rings offered by Federal-Mogul. Depending upon the level of wear resistance required by engine manufacturers, Federal-Mogul can apply a variety of surface treatments to piston rings, such as chrome, CKS (chrome ceramic coating) and GDC (Goetze diamond coating), which protect the ring periphery from scuffing, thus minimizing wear and enabling the oil ring to function properly over the life of the engine. The LKZ ring also can be coated with Federal-Mogul’s DLC (diamond-like carbon) coating to even further reduce engine friction.



Very nice. I wonder what this does to actual mpg? Where were these guys 20yrs ago? Nobody likes oil changes. The reigning technology champs aren't easy to knock out. They are champs for a reason. Nevertheless, champs do come and go. I imagine the ICE still has another 10yrs of life in it.


Wonder if these rings can be retrofitted when an engine is rebuilt?


Seems like a huge improvement for an apparently minor change.

Multi-Modal Commuter Dude (formerly known as Bike Commuter Dude)


Yes they will be. I know they'll be on the list for the next engine I build!

@ Kelly

In the near future, cloud computing will allow many incremental improvements like this. The fluid dynamic simulations must have been extremely processor intensive.


Piston ring manufacturer constantly work on issues like this. Therefore, it is difficult to say at this stage that this modification is more clever than any other modification. The general concept is that the ring land height is reduced and the ring tension is simultaneously reduced. Better coatings are also constantly developed for lower friction and reduced wear. Although the oil ring contribute with a large share of the friction, there are also two other rings to modify.

In general, the friction losses are higher for diesel engines than for gasoline engines, so one could assume that the potential for improvement is greater for the former. However, cylinder pressures are also higher for diesel engines implying that diesel probably never will be equal to gasoline engines in this respect.


This concept is nothing new! In the mid 1970's Evinrude and Johson 2 stroke outboard motors were able to go from 3 rings to 2 by using what they patented as "pressure back rings". They were more or less triangular with the ring being forced outward slightly on the compression /down stroke. They were effective and reliable.


The Ultralight Strategy. "The incremental approach to improvements saves so little fuel because it focuses disproportionately on fine points of engine and transmission design while comparatively neglecting the basic strategy of making the car very light and aerodynamically very slippery. This strategy rests on the basic physics of cars: in urban driving on a level road, drivewheel energy (typically only ~15-20% of fuel input energy) is devoted about one-third to heating their brakes when they stop, one-third to heating the air they push aside, and one-third to heating the tyres and road (MacCready 1991). On the highway, air resistance, proportional to the square of speed, accounts for ~60-70% of tractive energy needs. The keys to automotive fuel economy, therefore, are braking and downhill-coasting energy recovery, aerodynamic drag, tyre rolling resistance, and mass. Benefits from improving any one of these are limited, but benefits from improving all of them together are striking, and they often reinforce each other." [Lovins & Lovins, 1995]

All these people have done is reduce the friction on the smallest contact area in the engine - the piston rings. Now if they had reduced the friction of something big (like the crankshaft bearings) I'd be impressed.

Roger Pham

@ai vin,
Reducing engine friction is what a full HEV does best. The engine is shut down at lower power requirement, and the electric motor provides power. Also engine downsizing is done to reduce engine friction. Supercharging or Turbocharging with engine downsizing also accomplish friction reduction. Ford Fusion now uses thinner 5W-20 oil instead of 5W30 before.


Exactly my point, HEVs are not an incremental approach. They reduce friction in the whole engine (by shutting it down) and even allow for "braking and downhill-coasting energy recovery."


ICE is a dying technology. You may improve it by 50+% but it is on its way out.

Mechanical watches went through the same evolution change a few decades ago. Today, my sun powered watch looks like a mechanical unit but it has never stopped or been adjusted for the last 6 years and it is still right on time. That is an example of what EVs will do to ICE vehicles.

One day, ultra light EVs, with ultra high efficiency (50+%) transparent solar cells over windows, roof and body may operate much like my sun powered precision watch. Charge points would only be required for long trips and night time travel.


Ah yes, the future of the car is so easy to predict;

And highways too;


2-stroke engines do not need an oil ring. The "invention" by Federal-Mogul has nothing to do with ring packs once used on 2-stroke engines. In some sense, it is "new" but essentially, it is just one step more in the continous development of engine components.

The piston and ring pack has significantly higher friction than the crankshaft. The oil ring has the highest friction of all rings. This is basic knowledge for engineers. The size of the component does not matter. Roller bearings is one option for the crankshaft (and camshaft) but this development is not ready yet.

Well, if a HEV has as good - or better - well-to-wheel efficiency as an EV (shown by MIT and others), which one is closer to death? We have seen the EV die two times already, in the 1970´s, the 1990's and now we might see this for the third time. In 1975, senator Muskie was proud of the emission regulation that would kill the ICE car in a couple of years. What happened? The ICE still lives... Solar cells? Do you really believe in solar cells to charge the batteries for your EV? You must be dreaming. At a more realistic 10% efficiency and an area of 1 m3, it is just enough for the headlights.

Henry Gibson

The electric vehicle needed an economy of scale and also a cheaper battery or better said a lower up front cost. The batteries should be bought by the electric companies and paid for by the month along with the power bill. An electricity consumer does not have to pay for his total share of the up front costs of the grid and generators when he builds a new house.

The totaly false view that electric cars must have as long a range as gasoline vehicles and a short recharge time is eliminated with the use of tiny range extending generators, and the Volt generator is much too much overkill.

Expensive electric cars, TESLA ETC., were not designed for cheap production and low operating costs but for advertizing purposes. TATA needs to produce an electric car that the motor and electronics does not cost more than a far more complicated internal combustion engine.

Lower upfront costs are also achieved by weak hybrids with small low power range extenders that can reduce battery costs by half or more and allow the use of cheap batteries, including lead ones. Flywheels can be used with smaller batteries to give very high power acceleration and regenerative braking. It has been demonstrated that flywheels can be used in race cars even. A Prius needs only six kilowatts or eight horsepower to travel at a constant 30 miles per hours. The fuel economy of an automobile shows how low a horsepower is actually produced on the average.

Co-generation at home for electric car charging increases the efficient use of fuels and lowers green house gas production substantially at far lower costs than the use of solar cells and should be promoted with more speed than vehicle to grid connections, V2G, and allows for the fastest charging without putting an additional massive load on the grid. It also can provide grid assistance, but remote control of airconditioners can provide this at far lower costs

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