Significant progress has been achieved in the development of advanced high-temperature, insulated, in-cylinder components for high-power-output miliraty diesel engines. Computer aided modeling and small-bore engine component testing have both been utilized extensively during the exploratory development process. Specific insulated optimal designs for the piston, cylinder headface, and cylinder liner have been identified. The designs all utilize thermal barrier coatings, titanium alloy, and interfacial air-gaps to provide thermal resistance.
Finite element modeling including diesel cycle simulation has been utilized to screen and optimize material and design concepts relative to program objectives, while small-bore engine testing has been utilized to demonstrate component integrity.
An improved slurry densified thermal barrier coating has been demonstrated by testing on a high temperature small-bore engine. Titanium Alloy and Steel pistons were coated with various 1.25 mm thick thermal sprayed zirconia coatings. All of the coatings experienced failure by cracking except for the slurry densified coating.