Methods and systems are provided for regulating exhaust flow through an exhaust system of an engine. In one example, a method may include directing exhaust from downstream of a catalytic converter to a compressor storage tank in response to an engine air-fuel ratio deviating from stoichiometry. The stored exhaust may be released from the compressor storage tank to recirculate through the catalytic converter to atmosphere after adjusting an air-fuel ratio of the exhaust in the storage tank and when the catalytic converter is at a target operating temperature.

Methods and systems are provided for regulating exhaust flow through an exhaust system of an engine. In one example, a method may include directing exhaust from downstream of a catalytic converter to a compressor storage tank in response to an engine air-fuel ratio deviating from stoichiometry. The stored exhaust may be released from the compressor storage tank to recirculate through the catalytic converter to atmosphere after adjusting an air-fuel ratio of the exhaust in the storage tank and when the catalytic converter is at a target operating temperature.

Methods and systems are provided for diagnosing temperature sensors of a vehicle. In one example, a method may include, at a duration after an engine-off event, determining that an intake air temperature measured by an intake air temperature sensor of the vehicle is less than an ambient air temperature measured by an ambient air temperature sensor of the vehicle. In response to the determining, the method may include flowing air from a catalyst across the intake air temperature sensor; and indicating the intake air temperature sensor is functional responsive to the intake air temperature converging to the ambient air temperature during the flowing.

Methods and systems are provided for diagnosing temperature sensors of a vehicle. In one example, a method may include, at a duration after an engine-off event, determining that an intake air temperature measured by an intake air temperature sensor of the vehicle is less than an ambient air temperature measured by an ambient air temperature sensor of the vehicle. In response to the determining, the method may include flowing air from a catalyst across the intake air temperature sensor; and indicating the intake air temperature sensor is functional responsive to the intake air temperature converging to the ambient air temperature during the flowing.

Each of a plurality of control devices (10, 11, 12) of an engine control system (1) is provided with a drive control unit (100, 110, 120) which controls the drive of an engine unit to be controlled according to memory information stored in a memory of the control device, a memory information output unit which outputs the memory information stored in the memory of the control device to other control devices, and a memory information update unit which writes memory information received from the memory information output units of other control devices into the memory of the control device.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

An engine system incorporating an intake manifold, a compressor, and a controller. The compressor may provide air to the intake manifold and the controller may be connected to the intake manifold and the compressor. The controller may receive a control signal and control air flow from the compressor to the intake manifold based on the received control signal. The controller may control the air flow from the compressor to the intake manifold based on a first equation when a value related to the control signal is on a first side of a threshold and according to a second equation when the value is on a second side of the threshold. The controller may control the air flow between the compressor and intake manifold according to the second equation to prevent the compressor from operating at a surge condition when controlling the air flow according to the first equation.

An engine system incorporating an intake manifold, a compressor, and a controller. The compressor may provide air to the intake manifold and the controller may be connected to the intake manifold and the compressor. The controller may receive a control signal and control air flow from the compressor to the intake manifold based on the received control signal. The controller may control the air flow from the compressor to the intake manifold based on a first equation when a value related to the control signal is on a first side of a threshold and according to a second equation when the value is on a second side of the threshold. The controller may control the air flow between the compressor and intake manifold according to the second equation to prevent the compressor from operating at a surge condition when controlling the air flow according to the first equation.

A first limit requesting process limits a dither control process of fuel injection valves in such a manner that the absolute value of the difference between the air-fuel ratios of the cylinders becomes smaller when the degree of variation of the injection amounts of the fuel injection valves provided for respective cylinders is great than when the degree of variation is small. A second limit requesting process limits the dither control process in such a manner that the absolute value is smaller when the torque fluctuation amount of the internal combustion engine is great than when the torque fluctuation amount is small. The limiting process limits the dither control process in accordance with one of requests generated by the first limit requesting process and the second limit requesting process that causes the absolute value to be smaller than the other.