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Continued research into thermal barrier coatings (TBCs) for internal combustion engines has generated insights into the design of TBCs that can increase fuel conversion efficiency. In this work, two low thermal inertia TBCs (a commercially available Gen 1 material, Gadolinium Zirconate, and a proprietary Gen 2 material) were experimentally tested in gasoline compression ignition (GCI) on a light-duty single cylinder research engine. Compared to a metal baseline, a 250-micron thick Gen 1 coated piston produced an efficiency benefit of 0.4 percentage points (pp) at 6 and 10 bar net indicated mean effective pressure (IMEPn) and a 0.2 pp penalty at 15 bar IMEPn. The Gen 1 coating also showed an uHC and smoke penalty. An 80-micron thick Gen 2 coated piston showed an efficiency benefit of 0.9 pp at 6 bar IMEPn and 0.4 pp at 10 bar IMEPn, but an efficiency penalty of 0.5 pp at 15 bar IMEPn. The Gen 2 coating, which has a lower thermal inertia than the Gen 1 coating, displayed durability problems while the Gen 1 coating did not. A third piston was coated with a 120-micron thick Gen 2 coating everywhere except the high failure outer bowl region, which was coated with a 120-micron Gen 1 coating. This hybrid coating displayed good durability, an uHC emission penalty, a smoke benefit, an efficiency benefit of 0.1 pp at 6 bar IMEPn, an efficiency benefit of 0.4 pp at 10 bar IMEPn, and no change in efficiency at 15 bar IMEPn. These results indicate that a durable Gen 1/Gen 2 coating can provide an efficiency benefit to GCI combustion, and that further improvements on piston-spray interaction optimization and surface sealing of the TBC, as well as increasing the coated combustion chamber surface area (e.g. head and valves) can add further improve efficiency. [ABSTRACT FROM AUTHOR]

The application of thermal barrier coatings (TBCs) for internal combustion engines has drawn more research attention in recent years due to the improved coating technology and advanced material properties. This paper presents the combination of thermal barrier coatings with an advanced combustion concept: gasoline compression ignition (GCI). This study aims to evaluate the coating performance with GCI combustion on Aramco's light-duty GCI engine. The thermodynamic engine model has been established and collaborated with CFD results to investigate thermal barrier coatings for GCI with a PPCI-diffusion combustion strategy primarily at a load of 23.5 bar IMEPg. Two real-world coating materials were pre-selected as Gen.1 and Gen.2 candidates. The investigation consists of three main topics: the effect of coating thickness on GCI, the effect of intake boost on the performance of traditional coatings and temperature swing coatings, and the effect of combustion chamber coverage on engine performance. The result shows that the TBC thickness became the key parameter to optimize for TBC with GCI combustion mode, and in the end, 250–500 microns is recommended based on the temperature limit of ceramic material. It was also found that the high level of intake boosting could significantly alleviate the charge heating penalty. The coverage of piston, engine head, and both intake and exhaust valves should be applied to achieve the highest efficiency gains. It was found that the gain ratio from each chamber component can be drastically different at different loads. [ABSTRACT FROM AUTHOR]