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This specification covers the engineering requirements for applying tungsten carbide/cobalt coatings to metal parts by the detonation process and the properties of such coatings.

Currently there are three different types of bore solutions for small engines. 1) High silicon aluminum running with cast iron piston rings and a coated piston 2) Cast iron liner fitted to an aluminum block or cylinder 3) Nickel composite coating on an aluminum liner, cylinder, or block. A new method and apparatus has been developed to reduce the manufacturing tasks and costs of a bore solution. ...This new method involves turning a liner from aluminum and coating with nickel-silicon carbide. For the finish honing, an apparatus was developed that enables a liner to be honed for interference or clearance bonded fit into the block or the cylinder. ...The first part addresses the manufacturing and installation of liners and the second part gives engine designers some specifics of nickel ceramic composite electrolytic coatings.

Among them, plasma transferred wire arc (PTWA) thermal spraying coating is becoming popular. Plasma electrolytic oxidation (PEO) coating is also proposed for increasing the wear resistance of aluminum alloy and reducing the friction between the cylinder and piston. ...In this work, a PEO coating with a thickness of ∼20 μm was prepared, and a high speed pin-on-disc tribometer was used to study the tribological behavior of the coating at oil lubricant conditions. Different surface roughness of the coating and a large range of the sliding speeds were employed for the tests. ...In this work, a PEO coating with a thickness of ∼20 μm was prepared, and a high speed pin-on-disc tribometer was used to study the tribological behavior of the coating at oil lubricant conditions.

The first-ever application of a hydrogen-free diamond-like carbon (H free DLC) coating to a mass-production gasoline engine reduces friction between the cylinder bore and piston by 18%. ...Because low friction coating is effective in a thin oil film at a large area near top dead center (TDC). It is also found that the friction reduction effect is enhanced when low viscosity engine oil is used. ...DLC as a low friction coating is more effective in a thinner oil film. In this study, the adhesion strength of H-free DLC coating on piston rings is improved because of providing a smooth substrate, the new washing process and the optimized coating characteristics.

Army Tank Automotive Research & Development Engineering Center (TARDEC) has developed a low cost, durable ceramic composite cylinder bore coating for diesel engines operating under severe conditions. This bore coating is a ceramic composite consisting primarily of Iron Oxide, Iron Titanate and Partially Stabilized Zirconia. ...It is applied by unique chemical thermal bonding technology developed at Adiabatics, Inc. and is referred to as Low Temperature Iron Titanate (LTIT). This coating has been tested against a wide range of cylinder bore treatments ranging from hard chrome plate to hard Nickel Silicon Carbide (NikaSil) and found to provide a superior sliding wear surface. ...It is superior because it is compatible against most common piston ring materials and coatings. As compared to other liner treatments, it displays superior running in or break in performance of the ring against the cylinder liner and yields significantly better wear rates under high wear extreme loading engine operating conditions.

This Paper presents comparative analysis of heat release in base line and insulated (Piston crown with plasma sprayed zirconia coating) diesel engine. The coating system affects the fuel consumption, the power and the combustion efficiency, pollution contents and the fatigue lifetime of engine components. ...Experimental research of insulated diesel engine incorporating thermal barrier coating (TBC) has produced controversial result. Some publications report that engine efficiency increases with insulation, while others argue that efficiency decreases. ...Several disadvantages such as producing nitrogen oxides also exist when a coating system is used. In this Paper, all effects, advantages and disadvantages of thermal barrier coatings are investigated based on experimental result.

Thermal barrier coatings (TBCs) were used to simulate adiabatic engines with the intention not only for reduced in-cylinder heat rejection and thermal fatigue protection of underlying metallic surfaces, but also for possible reduction of engine emissions. ...The insulation of the combustion chamber with this coating, which is ceramic based, influences the combustion process and hence the performance and exhaust emissions characteristics of the engines. ...A plasma sprayed thermal barrier coating was deposited on top of a piston for a Diesel engine and its effect on the engine performance is studied.

In order to attend to these demands, MAHLE has developed a novel high-performance polymer coating containing lubricant-filled microcapsules. The Microcapsules are designed to rupture during nascent scuff and high wear events and consequently release the contained lubricant ‘on demand’. ...A clear tendency for the novel polymer coating to provide improved recovery after scuffing events was measured, allowing for continuing safe operation of the bearings and thus reducing the seizure risk. ...As an additional benefit, the microcapsulefilled polymer coatings provide a wear improvement of more than 20% compared to current polymer bearing coatings.

The properties of Diamond-like carbon (DLC) coatings are known to offer superior wear resistance and low friction making it suitable for many different tribological applications. ...Test results show that DLC coating improved tribological system decreasing friction losses by 19%. Finally, results from a short durability test on HDD engine platform have confirmed a significant reduction of 2.5% on specific fuel consumption as well as superior wear resistance of DLC-coated cylinder liners when compared with base-uncoated ones.

The friction force of the nano diamond polymer coating is 21% lower than graphite coating and 7% lower than MoS₂ coating. Furthermore, in contrast to the MoS₂ coating, the nano diamond polymer coating showed no wear mark after the test. ...The properties of coating were tested using Ball-on-Plate tribology test machine. As a result, the coating containing 1 wt% of nano diamond and 4 wt% of amino functional silane compared to the nano diamond contents showed the lowest fiction coefficient and wear rate. ...Furthermore, in contrast to the MoS₂ coating, the nano diamond polymer coating showed no wear mark after the test. Using the real engine test, the nano diamond polymer coating showed 1.8% decrease in friction force measured as FMEP compared to the MoS₂ coating which is on mass production and nano diamond polymer coating showed superior durability according to the full load and full speed engine test.

Ni-SiC coating commercially known as NIKASIL, is the most commercially used coating in automobile’s/aero IC engines. ...Present study provides an oxide namely Yttria Stabilized Zirconia (YSZ) reinforced Nickel-Cobalt based wear-resistant and fuel-saving composite coating replacing the existing NIKASIL coating used in automobile engines. The said wear-resistant coating was developed using simple electrochemical deposition method. ...The deposition conditions were optimized and the developed coating displayed a microhardness of 500 ± 30 KHN50gf. The wear loss of Ni-Co-YSZ coating was observed to be 6.7 × 10-7 mm3/m against EN31 hardened steel.

When the EGR rate is increased in a VC-Turbo engine, the combined effect of piston sliding and exhaust gas condensation at the top dead center accelerates the corrosive wear of the thermal spray coating. Stainless steel coating is used to improve the corrosion resistance, but the adhesion strength between the coating and the cylinder bores is reduced. ...Stainless steel coating is used to improve the corrosion resistance, but the adhesion strength between the coating and the cylinder bores is reduced. Trial production of the coatings with different linear expansion coefficients was conducted, and the sensitivity of the linear expansion coefficient and adhesion strength was obtained. ...By contrast, the surface observation of this coating after the honing process showed an increase in surface porosity. The martensitic content in the coating was reduced, and the appropriate martensitic content and chemical composition with the optimal corrosion resistance, adhesion strength, and surface porosity were found.

Plasma electrolytic oxidation (PEO) coating is considered as a hard ceramic coating which can provide a dimpled surface for oil retention to bear the wear and reduce the friction from sliding piston rings. ...Five different lubricating oils and two different loads were applied to do the tribotests and the COFs of a PEO coating were studied. The results show that the PEO coating indeed had a lower COF in a lower viscosity lubricating oil, and a smaller load was beneficial to form the mixed and hydrodynamic lubricating regimes earlier. ...When tested with a very high viscosity of oil, the counterpart material had a significantly less wear, which may indicate that such kind of oil would provide a piston ring with a better protection against the ceramic coating. Thus, a proper selection of lubricating oil for PEO coating would be a decisive factor for balance between reducing friction loss and piston ring wear in an IC engine.

A very promising technological alternative is the use of HVOF (high velocity oxygen fuel) deposited internal coatings, showing improved coating quality results compared to APS (atmospheric plasma spray) coatings. ...A very promising technological alternative is the use of HVOF (high velocity oxygen fuel) deposited internal coatings, showing improved coating quality results compared to APS (atmospheric plasma spray) coatings. Several HVOF (High Velocity Oxygen Fuels) coating processes (with different fuel gases/fluids) were compared and studied, with a complete mechanical characterization and evaluation of the coatings. ...Several HVOF (High Velocity Oxygen Fuels) coating processes (with different fuel gases/fluids) were compared and studied, with a complete mechanical characterization and evaluation of the coatings. Also an economical comparison for the different coating systems is shown.

Sealing these various hardware surface finishes is accomplished via a rubber on the surface. The coating's ability to conform to various surface irregularities while withstanding high temperatures, long term coolant and oil exposure, and joint shearing forces is paramount to long term sealing. ...This paper will explore the sealing capabilities of a highly conformable flouro-polymer rubber coating developed specifically to seal rougher surface finishes.

A new method was developed to help determine the conditions that would create adhesion strength of heat-resisting coatings formed in plasma spraying. This method is a combination of an experiment design that uses a Latin square and multiple regression analysis. ...The multiple regression equation gained through this study is also effective in comparing the heat resistance of the heat-resisting coating.

Thermal Barrier Coating is an attractive and promising method in providing thermal insulation for the engine components due to its good thermo-mechanical properties. ...This research has been executed on three cylinder naturally aspirated diesel engine to understand the effect of the ceramic compound coating Yttria-Stabilized Zirconia, on engine performance and emission characteristics. This investigation compares the performance & emission characteristics of two different configurations namely, Engine Build I (Baseline Engine) and Engine Build II (Ceramic coated on cylinder head (incl. valves) of the Engine). ...Test results revels, that Ceramic coating on Cylinder head produce a reduction in fuel consumption, delivers higher performance and better emission characteristics.

A method of microarc oxidation (MO) on aluminium-silicon alloys has been developed to provide a wear-resistant coating for the internal surfaces of an automotive cylinder block cast from aluminium-silicon alloys.

Using this benefit to reduce side forces by a longer connecting rod, the full friction reduction potential is achieved by a combination with a new low friction carbon based coating on the piston pin. The new coating shows best-in-class performance in terms of friction and high temperature resistance compared to currently available pin coatings. ...A piston compression height reduction in combination with carbon based piston pin coatings is enabling advancements in both demands. MAHLE implemented a new innovative metal joining technology by using laser welding to generate a cooling gallery. ...The new coating shows best-in-class performance in terms of friction and high temperature resistance compared to currently available pin coatings. The shorter compression height also results in reduced oscillating masses. This can be used for further weight reduction in the whole drivetrain, which allows the implementation of further systems for better fuel efficiency, e.g. waste heat recovery, without reducing payload.

The experimental investigation was conducted on a CI version Ricardo variable compression single cylinder naturally aspirated engine to examine the effects of ceramic coating on performance and exhaust emissions. Tests were carried out at 1500rpm over a wide range of part loads, varying injection timings and compression ratios (CR). ...The technology by which the piston head was insulated is much more economical and simpler than the plasma-spray process usually used for coating with ceramics. Results show that at 30% of the rated load, BSFC decreases upto 9.99% at 40° injection bTDC (before top dead centre) for CR-19 resulting higher thermal efficiency than base line engine.