Method of and system for purifying exhaust gas for engines
AssigneeMazda Motor Corporation
InventorsHirofumi Nishimura, Tadataka Nakazumi, Ken Umehara, Takanobu Morimasa, Masanori Misumi
Life of this patent
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Abstract
Exhaust gas temperature is raised after a cold engine start so as to rapidly activate a catalyst in an exhaust line by retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during a certain time interval and promoting combustion of the air-fuel mixture, thereby accelerating the catalyst to attain its effective activation temperature after the cold engine start as quickly as possibly.
Claims126
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a warmed condition of the engine;
- engine operation control means for controlling operation of the engine;
- combustion promoting means for promoting combustion of an air-fuel mixture in the engine;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during a time interval from an engine start, said temperature control means, while said thermal condition monitoring means detects a specified cold condition of the engine, causing said engine operation control means to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval and causing said combustion promoting means to promote combustion of said air-fuel mixture, wherein said engine operation control means further alters an exhaust air-fuel ratio in a range equal to or greater than 14.5 during said specific time interval, thereby accelerating said rise in exhaust gas temperature to an effective activation temperature after said engine start.
A method of purifying exhaust gas discharged from a reciprocating internal combustion engine equipped with a catalytic converter in an exhaust system, said exhaust gas purifying method comprising the steps of:
- monitoring a thermal condition of the engine after an engine start;
- retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center;
- and
- promoting combustion of said air-fuel mixture by controlling the engine to burn said air-fuel mixture with a high combustion efficiency so as to stabilize engine cycling, for a time interval so as to cause a rise in exhaust gas temperature when the engine is monitored to be still in a cold condition, and altering an exhaust air-fuel ratio in a range equal to or greater than 14.5 during said time interval, thereby accelerating a rise in temperature of said catalytic converter to an effective activation temperature.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a temperature condition of the engine;
- engine operation control means for controlling operation of the engine;
- turbulence generating means for generating enhanced turbulence of an air-fuel mixture in a cylinder of the engine;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during a time interval from an engine start, said temperature control means, while said thermal condition monitoring means detects a specified cold temperature condition of the engine, causing said engine operation control means to retard an ignition timing at which said air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval and causing said turbulence generating means to make an air-fuel mixture rate constant before an ignition time at which a spark plus is fired, to create a turbulent energy at said ignition time when said turbulence generating means is operated greater than a turbulent energy at said ignition time when said turbulence generating means is not operated and to maintain said turbulent energy after said ignition time, thereby accelerating said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a temperature condition of the engine;
- engine operation control means for controlling operation of the engine;
- turbulence generating means for generating enhanced turbulence of an air-fuel mixture in a cylinder of the engine;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during a time interval from an engine start, said temperature control means, while said thermal condition monitoring means detects a specified cold temperature condition of the engine, causing said engine operation control means to retard an ignition timing at which said air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval and causing said turbulence generating means to make an air-fuel mixture rate constant before an ignition time at which a spark plug is fired, to create a turbulent energy at said ignition time when said turbulence generating means is operated greater than a turbulent energy at said ignition time when said turbulence generating means is not operated and to maintain said turbulent energy after said ignition time, thereby accelerating said rise in exhaust gas temperature to an effective activation temperature after said engine start wherein said engine operation control means further alters an exhaust air-fuel ratio in a range equal to or greater than 14.5 during said specific time interval.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a warmed condition of the engine;
- engine operation control means for controlling operation of the engine and altering an exhaust air-fuel ratio in a range equal to or greater than 14.5 during a time interval from an engine start;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during said time interval and, while said thermal condition monitoring means detects a specified cold condition of the engine, for causing said engine operating control means to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval, so as thereby to accelerate said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a warmed condition of the engine;
- engine operation control means for controlling operation of the engine;
- combustion promoting means operative only during a cold condition of the engine for promoting combustion of an air-fuel mixture in the engine;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during said time interval and, while said thermal condition monitoring means detects a specified cold condition of the engine, for causing said engine operating control means to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval, so as thereby to accelerate said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitoring means for monitoring a warmed condition of the engine;
- combustion control means for generating enhanced turbulence of an air-fuel mixture in a cylinder of the engine;
- engine operation control means for controlling operation of the engine;
- and
- temperature control means for controlling a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during said time interval and, while said thermal condition monitoring means detects a specified cold condition of the engine, for causing said engine operating control means to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval, so as thereby to accelerate said rise in exhaust gas temperature to an effective activation temperature after said engine start.
A method of purifying exhaust gas discharged from a reciprocating internal combustion engine equipped with a catalytic converter in an exhaust system, said exhaust gas purifying means comprising the steps of:
- monitoring a thermal condition of the engine after an engine start;
- altering an exhaust air-fuel ratio in a range equal to or greater than 14.5 during a specified time interval from said engine start;
- and
- retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval so as to cause a rise in exhaust gas temperature when the engine is monitored to be still in a cold condition, thereby accelerating a rise in temperature of said catalytic converter to an effective activation temperature.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitor which monitors a temperature condition of the engine;
- engine operation control operative to control operation of the engine;
- turbulence generator which generates enhanced turbulence of an air-fuel mixture in a cylinder of the engine;
- and
- temperature control operative to control a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during a time interval from an engine start, said temperature control, while said thermal condition monitor detects a specified cold temperature condition of the engine, causing said engine operation control to retard an ignition timing at which said air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval and causing said turbulence generator to make an air-fuel mixture rate constant before an ignition time at which a spark plug is fired, to create a turbulent energy at said ignition time when said turbulence generator is operated greater than a turbulent energy at said ignition time when said turbulence generator is not operated and to maintain said turbulent energy after said ignition time, thereby accelerating said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitor which monitors a warmed condition of the engine;
- engine operation control operative to control operation of the engine and alter an exhaust air-fuel ratio in a range equal to or greater than 14.5 during a time interval from an engine start;
- and
- temperature control which controls a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during said time interval and, while said thermal condition monitor detects a specified cold condition of the engine, causes said engine operating control to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval, so as thereby to accelerate said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas for a reciprocating internal combustion engine of a vehicle, said exhaust gas purifying system comprising:
- thermal condition monitor which monitors a warmed condition of the engine;
- engine operation control operative to control operation of the engine;
- combustion promotor operative only during a cold condition of the engine for promoting combustion of an air-fuel mixture in the engine;
- and
- temperature control operative to control a rise in exhaust gas temperature to an effective activation temperature of said catalytic converter during said time interval and, while said thermal condition monitor detects a specified cold condition of the engine, for causing said engine operating control to retard an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during said time interval, so as thereby to accelerate said rise in exhaust gas temperature to an effective activation temperature after said engine start.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- ignition means extending in a combustion chamber of the engine for firing an air-fuel mixture;
- thermal condition monitoring means for monitoring a thermal condition of the engine;
- fuel supply control means for supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio of approximately 14.7 while the engine is monitored to be still in a cold condition after an engine start;
- and
- mixture control means for creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said ignition means ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- an air-flow sensor operative to detect of an intake air quantity introduced into the engine;
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to control said fuel injector to deliver fuel into said combustion chamber according to said intake air quantity so as to provide an exhaust air-fuel ratio of approximately 14.7 while said temperature sensor monitors said temperature of engine cooling water lower than a specified value;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion chamber before said spark plug ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- an air-flow sensor operative to detect of an intake air quantity introduced into the engine;
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- an igniter operative to fire said spark plug;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to provide an injection signal for causing said fuel injector to deliver fuel into said combustion chamber according to said intake air quantity so as to provide an exhaust air-fuel ratio of approximately 14.7 while said temperature sensor monitors said temperature of engine cooling water lower than a specified value, and to provide an ignition signal for causing said igniter to fire said spark plug at a point of time after top-dead-center in a compression stroke;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion before said spark plug ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- an air-flow sensor operative to detect of an intake air quantity introduced into the engine;
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- an igniter operative to fire said spark plug;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to provide an injection signal for causing said fuel injector to deliver fuel into said combustion chamber according to said intake air quantity so as to provide an exhaust air-fuel ratio of approximately 14.7 while said temperature sensor monitors said temperature of engine cooling water lower than a specified value, and to provide an ignition signal for causing said igniter to fire said spark plug at a point of time after top-dead-center in a compression stroke during a specified time interval from a point of time that said temperature sensor monitors said temperature of engine cooling water lower than said specified value and at a point of time before a top-dead-center in a compression stroke after said time interval;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion chamber before said spark plug ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- an air-flow sensor operative to detect of an intake air quantity introduced into the engine;
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- an igniter operative to fire said spark plug;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a heater equipped oxygen (O.sub.2) sensor disposed in the exhaust line and operative to monitor an oxygen concentration of the exhaust gas;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to provide an injection signal for causing said fuel injector to deliver fuel into said combustion chamber according to said intake air quantity in feed-forward control until said heater equipped oxygen (O.sub.2) sensor is activated after a point of time that said temperature sensor monitors said temperature of engine cooling water lower than a specified value and according to said intake air quantity and said oxygen concentration in feed-back control after said heater equipped oxygen (O.sub.2) sensor is activated, so as thereby to provide an exhaust air-fuel ratio of approximately 14.7, and to provide an ignition signal for causing said igniter to fire said spark plug at a point of time after top-dead-center in a compression stroke during a specified time interval from a point of time that said temperature sensor monitors said temperature of engine cooling water lower than said specified value and a point of time before top-dead-center in a compression stroke after said time interval;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion chamber before said spark plug ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- an igniter operative to fire said spark plug;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to provide an injection signal for causing said fuel injector to deliver fuel into said combustion chamber and an ignition signal for causing said igniter to fire said spark plug so as to provide an increase in cylinder pressure after a middle point in an expansion stroke while said temperature sensor monitors a temperature of engine cooling water lower than a specified value;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion chamber before said spark plug ignites said air-fuel mixture.
An engine control system for a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line for purifying exhaust gas from the engine, said engine control system comprising:
- an air-flow sensor operative to detect of an intake air quantity introduced into the engine;
- a spark plug extending in a combustion chamber of the engine which is fired to ignite an air-fuel mixture;
- a fuel injector operative to deliver fuel into said combustion chamber;
- a heater equipped oxygen (O.sub.2) sensor disposed in the exhaust line and operative to monitor an oxygen concentration of the exhaust gas;
- a temperature sensor operative to monitor a temperature of engine cooling water;
- a controller operative to provide an injection signal for causing said fuel injector to deliver fuel into said combustion chamber according to said intake air quantity in feed-forward control until said heater equipped oxygen (O.sub.2) sensor is activated after a point of time that said temperature sensor monitors said temperature of engine cooling water lower than a specified value and according to said intake air quantity and said oxygen concentration in feed-back control after said heater equipped oxygen (O.sub.2) sensor is activated, so as thereby to provide an exhaust air-fuel ratio of approximately 14.7;
- and
- an intake air passage connected to said combustion chamber to produce an air stream with which said substantially homogeneous distribution of said air-fuel mixture is created in said combustion chamber before said spark plug ignites said air-fuel mixture.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio greater than approximately 14.5 while the engine is monitored to be still in a cold condition after an engine start;
- and
- creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- and
- controlling combustion of an air-fuel mixture so as to provide an increase in cylinder pressure after a middle point in an expansion stroke while the engine is monitored to be still in a cold condition.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio greater than approximately 14.5;
- creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited;
- and
- retarding said ignition time to a point of time after top-dead-center while the engine is monitored to be still in a cold condition after an engine start.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio greater than approximately 14.5;
- controlling an intake air stream in said combustion chamber to create a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited;
- and
- retarding said ignition time to a point of time after top-dead-center while the engine is monitored to be still in a cold condition after an engine start.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio of approximately 14.7;
- creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited;
- retarding said ignition time to a point of time after top-dead-center while the engine is monitored to be still in a cold condition after an engine start;
- and
- monitoring an oxygen concentration of the exhaust gas by a heater equipped oxygen (O.sub.2) sensor disposed in the exhaust line so as to control fuel delivery into said combustion chamber according to at least said oxygen concentration in feed-back control.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio greater than approximately 14.5;
- creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited;
- retarding said ignition time to a point of time after top-dead-center while the engine is monitored to be still in a cold condition after an engine start;
- and
- introducing air into the exhaust line before the catalytic converter so as to provide said exhaust air-fuel ratio greater than approximately 14.5.
An engine control method of controlling engine operation to purify exhaust gas from a reciprocating internal combustion engine of a vehicle equipped with an exhaust gas purifying system having a catalytic converter in an exhaust line, said engine control method comprising the steps of:
- monitoring a thermal condition of the engine;
- and
- controlling combustion of an air-fuel mixture so as to provide an increase in cylinder pressure after a middle point in an expansion stroke while the engine is monitored to be still in a cold condition;
- supplying fuel into said combustion chamber so as to provide an exhaust air-fuel ratio greater than approximately 14.5;
- creating a substantially homogeneous distribution of said air-fuel mixture in said combustion chamber before said air-fuel mixture is ignited;
- and
- retarding said ignition time to a point of time after top-dead-center while the engine is monitored to be still in a cold condition after an engine start.
Dependencies are inferred from the claim text.