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High Temperature Wear Coatings for Improving High Output Military Diesel Engine Performance and Durability

Description:

TECHNOLOGY AREA(S): Ground Sea 

OBJECTIVE: To develop, examine, and evaluate the plausibility of diesel engine in-cylinder wear coatings to reduce high power density diesel engine friction and fuel consumption while maintaining military engine acceptable durability and reliability targets. 

DESCRIPTION: Future military combat engines require very low heat rejection and high engine power density in order to aid in minimizing the overall propulsion system size. Such engine performance characteristics include fundamental power cylinder tribology challenges associated with high in-cylinder temperatures and pressure inherent of low heat rejection diesel engine technology. One possible technology to aid in addressing such challenges are durable in-cylinder coatings capable of enduring mixed and boundary lubrication regimes at high oil temperatures over noticeably longer portions of the cycle time than standard commercial four-stroke diesel engines. An additional benefit from such coatings is possible engine friction reduction that correlates to reduced fuel consumption based on the particular duty cycle. The objective of this topic is to develop, examine, and evaluate in-cylinder wear coatings for high output, low heat rejection two and four stroke diesel engines that are durable, reduce engine friction by 15%, and decrease fuel consumption by 2% to 5 % based on engine speed and load. Such engines must operate on military fuels including DF-2, JP-8, and F-34 while utilizing 15W-40, OW-30, and 0W-20 oils for lubrication and cooling purposes. Additionally, such military engines must be able to operate under stringent desert like operating conditions nominally in the 125 F ambient temperature range that include engine oil sump temperatures exceeding 260 F. 

PHASE I: Identify and assess possible in-cylinder wear coatings that are plausible under the conditions described in the description section and also provide a relevant bench top demonstration of possible engine targeted candidates. Such an effort should include any necessary analysis to support coating selection candidates along with necessary material (composition) analysis. The outcome of this phase should be a selection of wear coating candidate(s) for evaluation in phase II. 

PHASE II: Demonstrate and validate the performance of the chosen phase I candidate wear coatings in a multi-cylinder two or four stroke diesel engine at relevant military operating conditions. Such a demonstration should focus both on the durability of the wear coating(s) and any associated engine friction and fuel consumption reductions. 

PHASE III: Develop a wear coating for in-cylinder components that could be readily used in both military and commercial diesel engines. It is envisioned that this technology could be beneficial for all diesel engine markets under the constraint that it is durable and reduces engine friction that ultimately reduces engine fuel consumption. 

REFERENCES: 

1: Wang, G., Nie, X., and Tjong, J., "Load and Lubricating Oil Effects on Friction of a PEO Coating at Different Sliding Velocities," SAE Technical Paper 2017-01-0464, 2017, doi:10.4271/2017-01-0464.

2:  Maurizi, M. and Hrdina, D., "New MAHLE Steel Piston and Pin Coating System for Reduced TCO of CV Engines," SAE Int. J. Commer. Veh. 9(2):270-275, 2016, doi:10.4271/2016-01-8066.

3:  Bergman, M., Bergwall, M., Elm, T., Louring, S. et al., "Advanced Low Friction Engine Coating Applied to a 70cc High Performance Chainsaw," SAE Technical Paper 2014-32-0115, 2014, doi:10.4271/2014-32-0115.

KEYWORDS: Wear Coatings, Tribology, Ceramics, Engine Friction 

CONTACT(S): 

Dr. Peter Schihl 

(586) 282-6147 

peter.j.schihl.civ@mail.mil 

Maged Tadros 

(586) 282-5438 

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