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(11) | EP 1 193 388 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Exhaust gas purifying apparatus for an internal combustion engine with a supercharger |
| (57) An exhaust gas purifying apparatus for an internal combustion engine with a turbocharger
is provided with an introduction port for EGR gas disposed upstream of a compressor
and a throttle valve disposed upstream of the introduction port, and comprised of
a fail safe means that the portion on the upstream side of the compressor does not
have any excessive negative pressure even if a malfunction occurs in the throttle
valve. The exhaust gas purifying apparatus for an internal combustion engine with
a turbocharger is provided with a supercharger (6) having a turbine (6b) disposed
in an exhaust passage (16) and a compressor (6a) disposed in an intake passage (3)
and having an exhaust gas recirculation system (23,24 and 25) for connecting the exhaust
passage (16) downstream of the turbine (6b) and the intake passage (3) with each other
and for recirculating a part of exhaust gas back to an intake system of the internal
combustion engine, wherein an introduction port for recirculating the part of the
exhaust gas and a throttle valve (20) for opening/closing the intake passage (3) as
desired are arranged in this order. A fail safe unit (21) for allowing a predetermined
flow rate of intake air to flow to the compressor (6a) and giving a load, when the
throttle valve (20) is fully closed, is provided in the intake passage (3) upstream
of the compressor (6a). |