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The technologies which comprise heat insulated turbo compound engine are summarized as (1) establishment of heat insulation structure. (2) improvement of combustion under high temperature ambient condition. (3) establishment of energy recovering from exhaust gas.

An adiabatic engine was constructed with the monolithic type ceramic material. A highly durable and superior heat insulating engine could be completed, through detailed study of the design, evaluating the ceramics of which reliability is inferior in strength, going back to the microstructure and improving it to the utilizable level as the engine parts. I started studying the combustion in a bid to accomplish improvement of the fuel consumption rate, realization of multi-fuel engine and pollution-lowering, but I found out that recovering of the ignition delay shortening can be coped with by high pressure injection, fuel nature modification and so forth. In future, I have to pursue my studies in connection with reduction of emission of exhaust gas like the NOx and recovery of energy from the exhaust gas, and the similar subjects.

Ceramics show high degree of heat resistance. But an attempt to build an adiabatic engine using ceramic materials should be carried out by full evaluation of characteristics of each ceramic material. The strength of ceramic parts are dependent on both their manufacturing processes and the mechanical and thermal stresses to which the parts are subjected. Full consideration should be given to these factors in evaluating ceramic parts. Even if a ceramic engine were manufactured after full consideration (1) to these factors, adiabatic engines proposed by R. Kamo and other researchers have had difficulty in realizing performance level and fuel economy as first suggested.

This paper describe the metal-to-ceramic joining method which is important for building ceramic adiabatic engine and deals with the potential of pistons for use for adiabatic ceramic engine. Although various ceramic-to-metal joining methods have been developed, the chemical bonding method such as brazing and diffusion bonding is not only inferior in complex joining process and heat resistance, but also incapable of attaining the bonding strength of 196Mpa required of engineering ceramics. The ceramic-to-metal bonding attained generally by mechanical method such as staking results in the failure of ceramic bonding face due to a strong shearing force accompanied by the plastic deformation of metal. Therefore, the reduction of the shearing force between the ceramic and metal materials and the improvement of plasticity of the metal are necessary.