초록 ▼

A closed loop Rankine bottoming cycle including a heat exchanger coupled to an exhaust port of a first turbogenerator for heating a pressurized refrigerant into a gaseous phase, and a second turbogenerator (e.g., a turbo expander) coupled to the heat exchanger for expanding the gaseous phase so as t

A closed loop Rankine bottoming cycle including a heat exchanger coupled to an exhaust port of a first turbogenerator for heating a pressurized refrigerant into a gaseous phase, and a second turbogenerator (e.g., a turbo expander) coupled to the heat exchanger for expanding the gaseous phase so as to create power. Also included is a cooling mechanism coupled to an exhaust of the second turbogenerator for cooling the gaseous phase exhausted by the second turbogenerator into a liquid phase, and a pumping mechanism for pressurizing the liquid phase into the pressurized refrigerant heated by the heat exchanger. A computer program product and method for operating and synchronizing the generator included in the closed loop, so as to optimize the overall system efficiency is also included.

대표청구항 ▼

A closed loop Rankine bottoming cycle including a heat exchanger coupled to an exhaust port of a first turbogenerator for heating a pressurized refrigerant into a gaseous phase, and a second turbogenerator (e.g., a turbo expander) coupled to the heat exchanger for expanding the gaseous phase so as t

A closed loop Rankine bottoming cycle including a heat exchanger coupled to an exhaust port of a first turbogenerator for heating a pressurized refrigerant into a gaseous phase, and a second turbogenerator (e.g., a turbo expander) coupled to the heat exchanger for expanding the gaseous phase so as to create power. Also included is a cooling mechanism coupled to an exhaust of the second turbogenerator for cooling the gaseous phase exhausted by the second turbogenerator into a liquid phase, and a pumping mechanism for pressurizing the liquid phase into the pressurized refrigerant heated by the heat exchanger. A computer program product and method for operating and synchronizing the generator included in the closed loop, so as to optimize the overall system efficiency is also included. loop controlling an air-fuel ratio based on a deviation between the target air-fuel ratio and an output of said first sensor; and a target air-fuel ratio limiter for limiting the target air-fuel ratio in a predetermined control range, wherein said target air-fuel ratio limiter shifts the control range based on an output of said second sensor and an output of said third sensor. 3. An exhaust emission control system according to claim 2, wherein at a time of shifting the control range, said target air-fuel ratio limiter sets a change value in accordance with at least one of the output of said second sensor and the output of the third sensor. 4. An exhaust emission control system according to claim 2, further comprising a control gain changer for changing a control gain of a second closed loop control for setting the target air-fuel ratio based on the output of said second sensor and the output of said third sensor. 5. An exhaust emission control system for an internal combustion engine, comprising: an upstream catalyst disposed in an exhaust passage; a downstream catalyst disposed in said exhaust passage, said downstream catalyst disposed at a downstream of and in series with said upstream catalyst; a first sensor for detecting an air-fuel ratio or a rich/lean state of exhaust gases flowing into said upstream catalyst; a second sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gases flowing from said upstream catalyst; a third sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gases flowing from said downstream catalyst; an air-fuel ratio closed loop controller for setting a target air-fuel ratio based on at least one of an output of said second sensor and an output of said third sensor, and closed loop controlling an air-fuel ratio based on a deviation between the target air-fuel ratio and an output of said first sensor; and a target air-fuel ratio limiter for limiting the target air-fuel ratio in a predetermined control range, wherein said target air-fuel ratio limiter shifts the control range based on an output of said second sensor and an output of said third sensor; said target air-fuel ratio limiter changes at least a rich-side limit value of the control range to a limit value having a lower degree of richness when both of the outputs of said second and third sensors are rich, and the target air-fuel ratio limiter changes at least a lean-side limit value of the control range to a limit value having a lower degree of leanness when both of the outputs of said second and third sensors are lean. 6. An exhaust emission control system for an internal combustion engine, comprising: an upstream catalyst disposed in an exhaust passage; a downstream catalyst disposed in said exhaust passage, said downstream catalyst disposed at a downstream of and in series with said upstream catalyst; a first sensor for detecting an air-fuel ratio or a rich/lean state of exhaust gases flowing into said upstream catalyst; a second sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gases flowing from said upstream catalyst; a third sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gases flowing from said downstream catalyst; an air-fuel ratio closed loop controller for setting a target air-fuel ratio based on at least one of an output of said second sensor and an output of said third sensor, and closed loop controlling the air-fuel ratio based on a deviation between the target air-fuel ratio and the output of said first sensor; and a control gain changer for changing a control gain of a second closed loop control for setting the target air-fuel ratio based on the outputs of said second and third sensors. 7. An exhaust emission control system according to claim 6, wherein at a time of changing the control gain, said control gain changer sets a change value in accordance with at least one of the output of said second sensor a nd the output of said third sensor. 8. An exhaust emission control system for an internal combustion engine, comprising: an upstream catalyst disposed in an exhaust passage; a downstream catalyst disposed in said exhaust passage, said downstream catalyst disposed at a downstream of and in series with said upstream catalyst; a first sensor for detecting an air-fuel ratio or a rich/lean state of an exhaust gas flowing into said upstream catalyst; a second sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gas flowing from said upstream catalyst; a third sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gas flowing from said downstream catalyst; a downstream-side second closed loop controller for setting a target output of said second sensor based on an output of said third sensor; an upstream-side second closed loop controller for setting a target output of said first sensor based on a deviation between an output of said second sensor and the target output of said second sensor; an air-fuel ratio closed loop controller for closed loop controlling an air-fuel ratio based on a deviation between an output of said first sensor and the target output of said first sensor; a sensor diagnosing means for determining whether an output of said third sensor is normal or not; and a fail-safe means, when it is determined by said sensor diagnosing means that the output of said third sensor is not normal, for inhibiting an operation of said downstream-side second closed loop controller and setting the target output of said second sensor to a learn value or a predetermined set value; wherein even in a case where said third sensor is not abnormal, if a temperature of said third sensor has not increased to an active state, said sensor diagnosing means determines that the output of said third sensor is not normal. 9. An exhaust emission control system for an internal combustion engine, comprising: an upstream catalyst disposed in an exhaust passage; a downstream catalyst disposed in said exhaust passage, said downstream catalyst disposed at a downstream of and in series with said upstream catalyst; a first sensor for detecting an air-fuel ratio or a rich/lean state of an exhaust gas flowing into said upstream catalyst; a second sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gas flowing from said upstream catalyst; a third sensor for detecting an air-fuel ratio or a rich/lean state of the exhaust gas flowing from said downstream catalyst; a downstream-side second closed loop controller for setting a target output of said second sensor based on an output of said third sensor; an upstream-side second closed loop controller for setting a target output of said first sensor based on a deviation between an output of said second sensor and the target output of said second sensor; an air-fuel ratio closed loop controller for closed loop controlling an air-fuel ratio based on a deviation between an output of said first sensor and the target output of said first sensor; a sensor diagnosing means for determining whether an output of said third sensor is normal or not; and a fail-safe means, when it is determined by said sensor diagnosing means that the output of said third sensor is not normal, for inhibiting an operation of said downstream-side second closed loop controller and setting the target output of said second sensor to a learn value or a predetermined set value; wherein when it is determined by said sensor diagnosing means that the output of said third sensor is not normal, said fail-safe means lowers at least one of a control gain and a control range of a second closed loop control for setting the target output of said first sensor as compared with those in a normal state. 10. An exhaust emission control system for an internal combustion engine, comprising: an upstream catalyst disposed in an exhaust passage; a downstream catalyst disposed