Toyota Develops Technology to Reduce Engine
Wear and Increase Fuel Economy

Tokyo―TOYOTA MOTOR CORPORATION announced today that it became the first automaker to develop a pioneering, fuel-saving technology that reduces wear and rotational resistance between the camshaft and valve-lifter shims by coating the shims with titanium nitride.

Because Toyota has always been conscious of the environment when designing automobiles, it has developed engines that more efficiently utilize resources and control carbon dioxide emissions. One method to achieve this is to reduce resistance and wear of rotating and reciprocating engine components.

In engines such as the Toyota twin-cam, where the cams are rotated by camshafts to open air intake and exhaust valves, coin-shaped shims are placed between each cam and valve. Toyota engineers designed a process by which the shim surface that contacts the cams is mirror-finished to a degree equivalent to that found in precision machined parts and then hardened significantly with a titanium nitride coating. Moreover, the coating's microscopic protrusions further polish the surfaces of the cams that they come into contact with. This results in an unsurpassed smoothness between all of the contact surfaces, thus reducing rotational resistance on the camshaft by 40% and improving fuel economy by 1-2% (10･15 mode).

Toyota is planning to combine this with already developed technologies that improve fuel consumption, and incorporate it into future engine models.