Release: July 3, 1998
NGK INSULATORS, LTD. (President: Masaharu Shibata, Head Office: Nagoya) started mass production of hexagonal cell ceramic substrates for automotive catalytic converters which NGK and TOYOTA (President: Hiroshi Okuda, Head Office: Toyota city, Aichi pref.) jointly developed. The newly developed substrates are supposed to be employed for direct-injection engines, "Toyota D-4".
"HONEYCERAM®", a ceramic substrate widely used for automotive catalytic converters, generally consists of square cells. The catalyst which purifies exhaust gas is coated onto inside cell walls. In square cells, the catalyst coated at the four corners becomes thicker than the other part, so the thicker part is not as efficient as the other part. As for the newly developed substrate, NGK and TOYOTA succeeded in achieving uniform thickness of the catalyst coating by hexagonal cells, thereby increasing the effective volume of the catalyst coating by 20%.
It had been more difficult to manufacture extrusion dies for hexagonal cell substrates than square cell ones. In addition, hexagonal cell substrates were easily deformed during the forming process. NGK succeeded in overcoming such problems by improving production technology. Deformation of hexagonal cells had lowered the strength of substrates. By preventing such deformation, the newly developed hexagonal cell substrates for automotive catalytic converters have the same strength as square cell ones.
NGK is now planning to expand production of hexagonal cell substrates in accordance with the market's demand.