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> SnakeSkin Superfinish - Economical Friction Reducing Solution


Introduction

The joint efforts of SINUS research and development (R&D) team and local Israeli R&D Start-up Company, have successfully brought to the creation of a new and innovating surface superfinish treatment on engine valves.

SnakeSkin is a friction reducing superfinish that is deposited on the valve’s stem metallic surface.

the main goal behind the development and adaptation of the process to the engine valves field, was to present the global automotive industry in general, and companies that act in the engine valves market in particular, with a brand new friction reducing solution that manages to significantly decrease the friction coefficient property of the valve’s stem inside the guide, in a highly efficient manner, while obtaining, as an added value, improved wear resistance and durability properties.

Another important goal that accompanied the implementation process, was to incorporate this innovating Superfinish treatment with our existing production equipment, in a manner that will allow us to present customers with valves featuring the optimum friction reduction property, at a cost that will be significantly less expensive than parallel solutions in this market, aiming to provide similar properties only at much higher cost.

Nowadays, the most common solutions in the field of friction reduction are special coatings like DLC (Diamond like Carbon), Titanium Nitride (TiN), Chromium Nitride (CrN) at cetera. These coatings will present the end user with valves that feature friction reducing properties but at the same time, the valve’s basic price will raise significantly due to the high cost of the deposition process, usually performed by PVD – physical vapor deposition process. Normally, engine valves manufacturers or coating companies, will require a rather substantial minimal quantity of parts that are to be coated and sometimes even ask the customer to pay a certain share of the tooling preparations that are inevitable when facing a part that hasn’t been treated by them in the past. All together, even though such coatings and treatments have been proven as highly efficient, on many cases it is the high cost of the end product that causes engine valves vendors to settle on a more basic finish grade for the valves they supply their customers with.

The SnakeSkin Superfinish is an ultimate and economic solution that can serve the purposes of any company that acts in the engine valves market, wishing to offer its range of customers with a wider selection and an opportunity to purchase upgraded valves at affordable prices.

It has also been proven that when the SnakeSkin Superfinish is deposited on valves that were initially treated with a PVD coating, a far greater value will be obtained. The reason for this fact, is that the SnakeSkin Superfinish deposition doesn’t subtract any property achieved by any coating process, therefore a phenomenon of properties incorporation accurse and the end product becomes far more superior then it should have been if it was treated with a coating process alone.

The Process

The SnakeSkin Superfinish is consisted of two separate Sub-processes. Each Sub-process is individual and intendeds to significantly decrease the valve’s friction coefficient, thus directly improving the valve’s wear resistance and durab
ility properties. These properties are constantly subjected to improvement attempts by engine valves manufacturers and surface treatment providers from around the globe.

The first stage is the creation of a grooved pattern on the valve’s stem metallic surface. This Sub-process is referred to as SnakeSkin Grooving due to the resemblance between the pattern and the texture of a snake’s skin. The SnakeSkin Grooving is designed to create an oil reserving layer on top of the valve’s stem surface. The main objective of such layer is to add lubrication and increase durability, especially under oil starvation or boundary lubrication conditions that are highly common in racing engines that constantly run at high RPM’s or heavy duty and industrial engines that are subjected to long operation hours at full capacity.

The creation of oil reservoirs on an engine valve’s stem is not an innovation as a process due to the fact that it was attempted and performed since the late 1960’s. However, neither one of the available treatments offered in that field, has ever managed to significantly improve the valve’s durability or wear resistant properties that are directly challenged under such engine conditions. The true innovating achievement behind the SnakeSkin Grooving is its ability to successfully improve the quality features and properties that other treatments failed to improve.

The second and completing Sub-process is the deposition of a special polymer done using a dedicated polymer lapping device. The polymer deposition creates an organic oil-retaining nanolayer on the valve’s stem surface. When combined with the SnakeSkin Grooving process, this organic layer is covering the edges of the grooving pattern and a solid oil retaining layer is created. The combination of both processes, and correct selection of a proper grooving pattern, brings to properties incorporation that has shows excellent results and significant performance benefits on specific applications.

Each of the sub-processes can act as an individual finishing treatment that will lead to friction reduction between the valve’s stem inside the guide. The reduction of friction will directly reflect and improve the valve’s durability and wear resistance properties. However, it has been proven that in order to achieve significant results, improve the engine’s overall mechanical efficiency, obtain highly improved yet durable engine performance, and significantly increase the valve’s lifespan, the full SnakeSkin Superfinish process is required.

Valves featuring the SnakeSkin Superfinish were tested and are now in constant use by many of SINUS customers acting in the fields of high performance racing engines, heavy duty diesel and natural gas engines, industrial engines, and dedicated engines for military and defense applications.

Testing and evaluation of this innovating process are still taking place by new and existing customers and results are very promising.