Abstract: Systems and methods are provided for diagnosing cylinders. In one example, a system includes an engine having a plurality of cylinders coupled to a crankshaft, a crankshaft speed sensor, and a controller. The controller is configured to receive a first output from the crankshaft speed sensor during nominal engine operation, receive a second output from the crankshaft speed sensor during engine operation where a fueling disturbance is introduced to a cylinder of the plurality of cylinders, indicate that the cylinder is unhealthy responsive to a difference between the first output and the second output being less than a threshold difference, and adjust one or more operating parameters of the engine in response to the indication.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to one or more of intake manifold air temperature (MAT), intake air flow rate, or a sensed or estimated intake oxygen fraction by changing an exhaust gas recirculation (EGR) amount to maintain particulate matter (PM) and NOx within a range, and then further adjusting the EGR amount based on NOx sensor feedback.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: Various methods and systems are provided for calibrating one or more exhaust valves. In one example, a system comprises an exhaust valve configured to control flow of exhaust gas exiting an engine and a controller configured to calibrate the exhaust valve by commanding the exhaust valve to a fully closed position with a first driving current and measuring a first position of the exhaust valve at the first driving current, commanding the exhaust valve to a fully open position with a second driving current and measuring a second position of the exhaust valve at the second driving current, and generating a map based on a linear function determined from the first driving current, the second driving current, the measured first position, and the measured second position. The controller is further configured to adjust a position of the exhaust valve based on the map.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to one or more of intake manifold air temperature (MAT), intake air flow rate, or a sensed or estimated intake oxygen fraction by changing an exhaust gas recirculation (EGR) amount to maintain particulate matter (PM) and NOx within a range, and then further adjusting the EGR amount based on NOx sensor feedback.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to one or more of intake manifold air temperature (MAT), intake air flow rate, or a sensed or estimated intake oxygen fraction by changing an exhaust gas recirculation (EGR) amount to maintain particulate matter (PM) and NOx within a range, and then further adjusting the EGR amount based on NOx sensor feedback.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed or estimated intake oxygen fraction by controlling an exhaust gas recirculation (EGR) amount supplied to an engine to maintain a level of particulate matter (PM) in a determined PM range and a level of NOx in a determined NOx range, and adjusting a target intake manifold oxygen fraction or target intake manifold EGR fraction in response to a NOx sensor feedback signal.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: An engine system includes a plurality of cylinders including one or more donating cylinders and one or more non-donating cylinders. A control module controls an operation of the one or more donating cylinders relative to, or based on, the operation of the one or more non-donating cylinders.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: Various methods and systems are provided for controlling exhaust gas recirculation in an engine. One embodiment for a system comprises an engine having first and second cylinder groups, and an exhaust gas recirculation (EGR) passage coupled between the first cylinder group and an intake manifold of the engine, flow of EGR through the EGR passage controlled by one or more EGR exhaust valves, and a controller configured to maintain a target intake gas concentration by adjusting the one or more EGR exhaust valves and adjusting fuel injection amounts to the first cylinder group differently than the second cylinder group.

Abstract: Various methods and systems are provided for adjusting a turbine boost control actuator based on a single common reference value. In one example, a method for an engine includes adjusting a turbine boost control actuator to control an intake manifold pressure to a limit, the limit based at least in part on one or more of peak cylinder pressure, turbine speed, and a pressure difference across a turbine.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed or estimated intake oxygen fraction by controlling an exhaust gas recirculation (EGR) amount supplied to an engine to maintain a level of particulate matter (PM) in a determined PM range and a level of NOx in a determined NOx range, and adjusting a target intake manifold oxygen fraction or target intake manifold EGR fraction in response to a NOx sensor feedback signal.

Abstract: Various methods and systems are provided for calibrating one or more exhaust valves. In one example, a system comprises an exhaust valve configured to control flow of exhaust gas exiting an engine and a controller configured to calibrate the exhaust valve by commanding the exhaust valve to a fully closed position with a first driving current and measuring a first position of the exhaust valve at the first driving current, commanding the exhaust valve to a fully open position with a second driving current and measuring a second position of the exhaust valve at the second driving current, and generating a map based on a linear function determined from the first driving current, the second driving current, the measured first position, and the measured second position. The controller is further configured to adjust a position of the exhaust valve based on the map.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to one or more of intake manifold air temperature (MAT), intake air flow rate, or a sensed or estimated intake oxygen fraction by changing an exhaust gas recirculation (EGR) amount to maintain particulate matter (PM) and NOx within a range, and then further adjusting the EGR amount based on NOx sensor feedback.

Abstract: Various methods and systems are provided for adjusting a turbine boost control actuator based on a single common reference value. In one example, a method for an engine includes adjusting a turbine boost control actuator to control an intake manifold pressure to a limit, the limit based at least in part on one or more of peak cylinder pressure, turbine speed, and a pressure difference across a turbine.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: Various methods and systems are provided for controlling exhaust gas recirculation in an engine. One embodiment for a system comprises an engine having first and second cylinder groups, and an exhaust gas recirculation (EGR) passage coupled between the first cylinder group and an intake manifold of the engine, flow of EGR through the EGR passage controlled by one or more EGR exhaust valves, and a controller configured to maintain a target intake gas concentration by adjusting the one or more EGR exhaust valves and adjusting fuel injection amounts to the first cylinder group differently than the second cylinder group.

Abstract: In accordance with the embodiments of the present invention, an engine is disclosed. The engine includes at least one donor cylinder and at least one non-donor cylinder coupled to an intake manifold feeding intake air and an exhaust manifold. The exhaust manifold is configured to carry an engine exhaust emission from the donor cylinder and the non-donor cylinder. The engine also includes an exhaust gas recirculation manifold extending from the donor cylinder to the intake manifold for recirculating a donor cylinder exhaust emission from the donor cylinder to the donor, and non-donor cylinders via the intake manifold. The engine further includes an after-treatment system and a sensor configured to sense a temperature of the engine exhaust emission and a device configured to receive a sensing signal from the sensor and to control a parameter of the engine and a component of the engine in response to the sensing signal.

Abstract: In accordance with the embodiments of the present invention, an engine is disclosed. The engine includes at least one donor cylinder and at least one non-donor cylinder coupled to an intake manifold feeding intake air and an exhaust manifold. The exhaust manifold is configured to carry an engine exhaust emission from the donor cylinder and the non-donor cylinder. The engine also includes an exhaust gas recirculation manifold extending from the donor cylinder to the intake manifold for recirculating a donor cylinder exhaust emission from the donor cylinder to the donor, and non-donor cylinders via the intake manifold. The engine further includes an after-treatment system and a sensor configured to sense a temperature of the engine exhaust emission and a device configured to receive a sensing signal from the sensor and to control a parameter of the engine and a component of the engine in response to the sensing signal.