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DENSO Introduces Ultra-Thin Wall Ceramic Catalytic Substrate

22 December 1999

DENSO Introduces Ultra-Thin Wall Ceramic Catalytic Substrate Slated for Installation in Late-Model Cars to be Released Next Spring

    DETROIT, Dec. 21 -- DENSO Corporation, with North American
headquarters in Southfield, Mich., today announced it has, in a joint effort
with Toyota Motor Corporation, developed an ultra-thin wall ceramic catalytic
substrate with 50-micrometer*-thick cell walls, 70 percent thinner than the
most popular conventional substrate.
    This innovation will be installed on late-model cars scheduled to be
released next spring.
    The ceramic catalytic substrate is a cylindrical substrate comprising
thousands of honeycomb cells of about one-millimeter diameter.  Engine exhaust
emissions are passed through the cells, where hydrocarbons and nitrogen oxides
are treated through exposure to the catalyst adhering to the inside of the
cells.
    With only 50-micrometer-thick cell walls, this new ceramic substrate
reduces the resistance to flow when emissions are passed through the
substrate.  It also easily makes the substrate warm enough to work due to
reduction in substrate thermal capacity.  In addition, the larger number of
cells (900 cells per inch, more than double the conventional type) increases
the effective area of catalytic adhesion to cell walls.  This also improves
treatment efficiency of exhaust emissions.  The raw material is extruded and
molded into the ceramic substrate, which is then finished by drying and
baking.
    Three separate inventions** resulted in the developmenthin
wall ceramic substrate:
    -- A highly precise and accurate technique for mold-making to extrude 50-
       micrometer-thick cell walls;
    -- A technique for reinforcing the area around the substrate to counteract
       the loss of substrate strength resulting from thinner walls, and
    -- A technique for reinforcing the substrate's end face to prevent exhaust
       emissions from erosion.

    Another joint development with Toyota resulted in the development of three
new substrates, the first worldwide:
    -- A 150-micrometer-thick hexagonal cell substrate;
    -- A 100-micrometer-thick hexagonal cell substrate, and
    -- A 75-micrometer-thick square cell substrate which is 50 percent thinner
       than the conventional type.

    The last two devices are installed in the new Toyota Crown model
(hexagonal type installed in gasoline direct injection engines) which was
introduced in September.
    "DENSO continues to take up the challenge of improving motor vehicle
emissions with the introduction of this ultra-thin wall ceramic cell
substrate.  It is one of DENSO's many contributions to helping protect the
global environment," said Norio Omori, managing director of DENSO Corporation.
    Headquartered in Kariya, Aichi, Japan, DENSO Corporation worldwide employs
more than 72,000 people in 25 countries, including Japan and one region.
Sales for fiscal year 1998 totaled $14.5 billion.  In North America, DENSO
employs more than 11,000 people.  North American consolidated sales for 1998
totaled $3.1 billion.

    *  One micrometer equals 1/1000 mm.
    ** Patents pending in Japan, U.S.A. and Europe.