摘要 |
Internal combustion engine exhaust gas, passing unreacted through an exhaust gas catalytic or thermal reaction device during the warm-up period of the device, are directed to a rigid conduit that retains the entire flow. The conduit retains the unreacted gas in sequential alignment with a second non-harmful gas occupying the conduit prior to inflow of the unreacted gas. The second gas blocks flow of the unreacted gas out of the downstream end of the conduit and into the atmosphere. The length and diameter of the conduit minimizes mixing of the unreacted gas and the second gas, and minimizes the volume of the conduit required to retain the unreacted gas. After warm-up of the reaction device, the retained unreacted gas is recirculated to the engine induction system or the reaction device. This approach supplements the emission control of the reaction device by preventing emission of undesirable exhaust gas constituents during starting of the engine and warm-up of the reaction device.
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