2001-2002
 The Use of High Performance Coatings at Engine Components
This project I have worked at between april 2001 and september 2002, investigates the tribological processes  that occur between the piston pin and the piston rod bushing. 
The tribometer investigations had shown that if the piston pin is coated with a high performance layer, the piston rod bushing could be eliminated. The coating I have used is called Topocrom and it is developed by the swiss company WMV from Winterthur (Swiss). Topocrom is a chrome coating and it has a particular surface geometry. It retains very well the lubrication oil and reduces wear. 
Immersed Lubrication
The Topocrom Coating
Surface Lubrication
Using a 2002 Wazau Tribometer we measured the friction and wear processes that occur between the classic materials (steel vs. copper) and the new materials (steel vs. Topocrom) used in the pin-bushing tribo-couple.

Two types of lubrication have been used: surface lubrication and immersed lubrication, and also two testing modes: rotation (as a continous movement) and oscilation.  
Wazau trm5000 Tribometer
As expected there was less fricton in the classic tribo-couple than in the steel-Topocrom tribo-couple, but wear was dramatically higher. 
wear
friction coefficient
But, the results pictured above are from the rotation tests. A very important result was obtained at the oscilation tests, were the steel-copper friction coeff. was higher than the steel-Topocrom friction coeff. 

Conclusion

In order to achieve longer maintenance intervals (very important at high capacity diesel engines) the use of high performance anti-wear coating like Topocrom is a very good option. The  "classic" and the "modern" piston pin and  rod joint  was simulated using a tribosistem.Exstensive tribo-tests have shown that materials like Topocrom cause less wear and even less friction (especially in the case of oscilation experiments which reproduce very accurately the engine working conditions).


Contact Info  
Hosted by www.Geocities.ws

1