An exhaust purification system comprising an exhaust purification catalyst, a downstream side air-fuel ratio sensor, and a control device performing air-fuel ratio control for controlling an air-fuel ratio of exhaust gas and abnormality diagnosis control for diagnosing the downstream side air-fuel ratio sensor. In the air-fuel ratio control, the control device alternately and repeatedly switches the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst between a rich air-fuel ratio and a lean air-fuel ratio. In the abnormality diagnosis control, the control device judges that the downstream side air-fuel ratio sensor has become abnormal when the air-fuel ratio of the exhaust gas is made the rich air-fuel ratio by the air-fuel control and the output air-fuel ratio of the downstream side air-fuel ratio sensor changes from an air-fuel ratio richer than a predetermined lean judged air-fuel ratio to an lean air-fuel ratio.

A controller for an internal combustion engine includes an electronic control unit. The electronic control unit is configured to increase an air amount that is suctioned into a cylinder while maintaining the lean air-fuel ratio as a first torque increasing operation in a case where target torque is increased during the operation at the lean air-fuel ratio such that torque is increased. The electronic control unit is configured to compute limit torque as an upper limit of the torque that can be realized in a case where the lean air-fuel ratio is kept for a certain time from a current time point. The electronic control unit is configured to switch to the operation at the theoretical air-fuel ratio and increase the torque as a second torque increasing operation in a case where the target torque becomes higher than the limit torque during execution of the first torque increasing operation.

Embodiments described herein relate to systems and methods of cylinder deactivation in compression-ignition engines. An engine described herein can include N cylinders, with N being an integer of at least 2, with each cylinder including an inner surface, a piston disposed and configured to move in each cylinder of the N cylinders, an intake port, an exhaust port, and a fuel injector. The piston and the inner surface define a combustion chamber. A method of operating the compression ignition engine includes injecting a fuel into each of the combustion chambers, combusting substantially all of the fuel in the compression ignition engine, monitoring engine load of the compression ignition engine, and deactivating a cylinder of the N cylinders upon a decrease in load to less than (N−1)/N×FL, wherein FL is a full load at a given engine speed.

A watercraft propulsion system includes a propulsion unit to be driven by an engine. The engine includes a cylinder block, an air intake channel, an exhaust channel, a supercharging device, and a fuel injector. The watercraft propulsion system includes the engine, the propulsion unit to be driven by the engine, a rotation speed sensor to detect a rotation speed of the engine, an air intake pressure sensor to detect an air intake pressure of the engine, and a controller. The controller is configured or programmed to compute a command fuel injection amount so that the engine performs a combustion operation at an air/fuel ratio in a lean-burn range (lean-combustion range) according to the rotation speed detected by the rotation speed sensor and the air intake pressure detected by the air intake pressure sensor, and to drive the fuel injector based on the computed command fuel injection amount.

Systems and methods for improving regeneration of a particulate filter located in an exhaust system of a vehicle are presented. In one example, the particulate filter is regenerated when the vehicle is expected to operate in a stationary electric power generating mode where the vehicle supplies electric power to off-board electric power consumers.

Systems and methods determining a presence or absence of engine misfire at low engine load are disclosed. In one example, the presence or absence of engine misfire is based on a fuel target error value and an exhaust temperature error. Operation of an engine may be adjusted when engine misfire is detected.

A control apparatus for an internal combustion engine is configured, during a slightly stratified-charge lean-burn operation, to: calculate a basic total fuel injection amount based on a required torque; calculate a compression stroke injection amount based on an ignition delay index value; calculate, as a basic main injection amount, a value obtained by subtracting a compression stroke injection amount from the basic total fuel injection amount; calculate, based on an output value of an in-cylinder pressure sensor, an actual specified combustion index value that represents a main combustion speed or a combustion fluctuation rate; calculate a main injection correction term based on a result of a comparison between a target specified combustion index value or a tolerable specified combustion index value, and the actual specified combustion index value; and calculate a main injection amount by adding the main injection correction term to the basic main injection amount.

A control device of an internal combustion engine including an electronic control unit configured to execute: a base injection amount calculation process of calculating a base value; an injection valve operation process of operating the fuel injection valve; a feedback process of correcting an injection amount in the injection valve operation process; and a determination process of determining whether or not the amount of fuel flowing into the cylinders other than fuel injected from the fuel injection valve is equal to or larger than a threshold value. When it is determined as a result of the determination that the amount of fuel flowing into the cylinders other than the fuel injected from the fuel injection valve is equal to or larger than the threshold value, the electronic control unit (does not execute the process of injecting fuel from the fuel injection valve with the feedback process stopped.

A control apparatus for an internal combustion engine is provided. The control apparatus includes a turbocharger, a bypass passage, a wastegate valve, a catalyst device and a controller. The controller sets the wastegate valve to a closed state in a case where a warm-up execution condition is established, and performs A/F oscillation for increasing or decreasing the fuel injection amount so that lean combustion and rich combustion are alternately performed in a case where the temperature in the exhaust passage upstream of the turbocharger is beyond a predetermined reference value.

A device for measuring temperature of a turbine wheel in a turbocharger includes: a guide that passes infrared ray generated from the turbine wheel and includes a coolant path; a protection unit that protects an optical head which senses the infrared ray; and a signal processing unit that measures a temperature of the turbine wheel by processing a signal corresponding to the sensed infrared ray.