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There are several all-aluminum cylinder blocks. A typical example is a mono-block cylinder of alusil alloy produced by low pressure die casting. This material's resistance to abrasion and seizure, however, is not satisfactory for motorcycle; in addition, long processing time is another disadvantage. To cope with these problems, the authors developed a light and highly productive all-aluminum cylinder block with a cast-in liner through die casting. The liner is made from powder metallurgy composite (PMC) with 3 to 5 % alumina and 0.5 to 3 % of graphite additives. The PMC reconciles abrasion resistance and machinability. The hardness deterioration of the composite due to the heat at die casting is avoided by using heat-resistant rapidly-solidified powders, made from an aluminum-silecon-iron alloy, for the matrix.

A liquid phase sintered valve seat insert has been developed for use in high performance engine. The material consists of Fe-Cr-C sintered alloy in which hard alloys and lubricating alloys dispersed uniformly. High wear resistance can be attained through proper dispersion of these alloys in the matrix. Containing more than 10 % Cr, the matrix material has high heat resistance and creep strength. IN JAPAN MANY CAR manufacturers are now developing new types of maitenance-free engines. These new engines will have a higher performance than that of the present engines. To make high performance engines it is necessary not only to have a good design, but also to improve the material properties used for engine parts. A valve seat insert is one of these parts that must be improved. High performance engines need a valve seat insert that has both wear resistance and heat resistance properties.

Oil-pump rotors with a trochoidal tooth shape have many advantages compared with others, but the trochoidal tooth shape has not been sufficiently analyzed theoretically. So it is very difficult for the pump designer to decide the specifications for the trochoidal tooth shape, and it is also difficult for the supplier to meet the pump designer's requirements. We have been conducting theoretical analyses of trochoidal gears for several years, and have developed a system for designing the tooth shape. We can rapidly design the tooth shape, which meets the requirements of the pump designer, and develop the market for trochoidal gears by using this system. This paper shows the outline of the theoretical analysis, the outline of oil-pump rotors attached to crank shafts in automobiles as an example of the development of trochoidal gears, and some test results.