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240 Landmarks TopEmissions Treatment > Three-way catalyst system
 Three-way catalyst system
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This is a three-way catalyst device which performs oxidation and reduction at the same time and was developed to conform to the world's severest emissions regulations of the time in 1978. In 1977, the system was used in the EFI type M-EU engine installed in the Crown. This was the world's first application of a catalyst in a mass production system.
The engine in which this three-way catalyst emissions treatment device was installed used electronic fuel injection (EFI). It simultaneously performed oxidation and reduction of three elements (CO, HC and NOx) using one catalyst. For this purpose, the fuel injection amount must be constantly controlled to the stoichiometric air-fuel ratio (a weight ratio of 14.7) according to the volume of air. The amount of oxygen in the exhaust gas that flows into the three-way catalyst was detected by an O2 sensor. Then the fuel injection amount suitable to the amount of oxygen was calculated and controlled by a computer.
The three-way catalyst used at this time was a pellet type platinum rhodium series. Active constituents were supported on the surface of granular ceramics with a diameter of 2 to 4 mm. The surface area per 1 g catalyst reached 5 to 150 ㎡. Multiple ceramic grains were set in a metal case (catalytic converter), and the case was installed in the exhaust pipe between the exhaust manifold and muffler.
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Storage location:TOYOTA COMMEMORATIVE MUSEUM OF INDUSTRY AND TECHNOLOGY (1-35, Noritake Shinmachi 4-chome, Nishi-ku, Nagoya-shi, Aichi 451-0051)
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Year manufactured:1977
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Manufacturer:Toyota Motor Corporation
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Classification:Mass-production system
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Current status:On display (static): open to the public
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Model / Manufacture
Company name:Toyota Motor Corporation
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Location:Toyota Commemorative Museum of Industry and Technology
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Year of manufacture:1977
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Installation model / Engine / Fuel
Installation model:Toyota Crown
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