Exhaust control system for internal combustion engine
AssigneeMazda Motor Corporation
InventorsMitsuto Hitomi, Kenji Kashiyama, Ken Umehara
Life of this patent
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Abstract
An exhaust control system has a first catalytic device disposed in an exhaust line and a second catalytic device, which is smaller in capacity than the first catalytic device, disposed in the exhaust line upstream from the first catalytic device. The system includes a shutter device disposed in the exhaust line upstream from the first catalytic device. The shutter device is caused, by a controller, to close the exhaust line during a predetermined period from a start of engine cranking, before an engine is warmed up, and open the exhaust line after the engine is warmed up, thereby promoting activation of the catalytic devices.
Claims21
An. exhaust control system for purifying exhaust gases from an internal combustion engine through an exhaust passage, comprising:
- first catalytic means, disposed in said exhaust passage, for purifying exhaust gases;
- second catalytic means, smaller in capacity than said first catalytic means and disposed in said exhaust passage upstream from said first catalytic means, for purifying exhaust gases passed through said first catalytic means;
- shutter means, disposed in said exhaust passage upstream from said first catalytic means, for opening and closing said exhaust passage;
- temperature detecting means for detecting an engine cranking temperature during cranking of said engine;
- and
- control means for causing said shutter means to close said exhaust passage during a predetermined period from a start of cranking of said engine when said temperature detecting means detects an engine cranking temperature lower than a predetermined temperature and to open said exhaust passage after said predetermined period.
An exhaust control system for purifying exhaust gases from an internal combustion engine passing through an exhaust passage, said internal combustion engine being equipped with idle speed control means for allowing intake air to bypass a throttle valve in an intake passage so as to regulate an engine speed during engine idling, said exhaust system comprising:
- variable valve timing means for changing a valve overlap period during which an intake valve and an exhaust valve open simultaneously;
- shutter means, disposed in said exhaust passage, for opening and closing said exhaust passage;
- temperature detecting means for detecting an engine cranking temperature during cranking of said engine;
- engine operating condition detecting means for detecting ranges of engine operating conditions of said engine;
- and
- control means for causing said variable valve timing means to vary a timing at which said intake valve and said exhaust valve open and close so as to extend said valve overlap period so that it is longer while said engine operating condition detecting means detects a specific range of engine operating conditions when said temperature detecting means detects an engine cranking temperature lower than a predetermined temperature than when said temperature detecting means detects an engine cranking temperature higher than said predetermined temperature, and causing said shutter means to close said exhaust passage so that it becomes smaller while said engine operating condition detecting means detects said specific range of engine operating conditions when said temperature detecting means detects an engine cranking temperature lower than said predetermined temperature than when said temperature detecting means detects an engine cranking temperature higher than said predetermined temperature.
An exhaust control system for purifying exhaust gases from an internal combustion engine passing through an exhaust passage, said internal combustion engine being equipped with idle speed control means for allowing intake air to bypass a throttle valve in an intake passage so as to regulate an engine speed during engine idling, said exhaust system comprising:
- vehicle launching detecting means for detecting launching of a vehicle on which said engine is mounted;
- engine operating condition detecting means for detecting ranges of engine operating conditions of said engine;
- exhaust resistance regulating means, disposed in said exhaust passage, for regulating exhaust flow resistance of exhaust gases passing though said exhaust passage;
- and
- control means for causing said exhaust resistance regulating means to increase said exhaust flow resistance while said engine condition detecting means detects a specific range of engine operating conditions and to reduce said exhaust flow resistance after said vehicle launching detecting means detects a launch of said vehicle.
Dependencies are inferred from the claim text.