An apparatus includes a processing circuit structured to receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, receive a second signal indicative of a downstream air-fuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, determine an actual oxygen storage capacity of the catalyst based at least in part on the received first signal and the received second signal, compare the actual oxygen storage capacity to a maximum storage capacity, and provide a fault signal in response to the actual oxygen storage capacity exceeding the maximum storage capacity. The apparatus also includes a notification circuit structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.

An apparatus for controlling an internal combustion engine is provided. An engine includes a compression release mechanism and a fuel injection valve. The compression release mechanism variably controls the opening degree of a valve member, and thereby connects the combustion chamber of the engine with at least one of the intake passage and the exhaust passage in order to release in-cylinder pressure during at least the compression stroke. A controller controls the fuel injection valve to execute coasting with the fuel cut off in which the fuel is cut off under a predetermined condition, and while executing coasting with the fuel cut off, controls the compression release mechanism to increase the opening degree of the valve member of the compression release mechanism as the speed of the engine is higher.

An engine control device includes: a pre-ignition determination module that determines whether an operation state of an engine indicated by a rotation speed detected by a rotation speed detection unit and a load calculated by a load calculating module is in a pre-ignition occurring region; a catalyst protection determination module that determines whether the operation state of the engine is in a catalyst protection region; and a fuel cut execution control module that stops a fuel supplied to the engine, when a remaining amount of a fuel tank is determined to be smaller than a tank threshold value and the operation state is determined to be in the pre-ignition occurring region, and when the remaining amount of the fuel tank is determined to be smaller than the tank threshold value and the operation state is determined to be in the catalyst protection region.

A method for operating an internal combustion engine, in which fuel is supplied to the internal combustion engine by a rotary pump, and the speed of the pump and/or the electrical current for feeding the pump (pump current) is controlled in accordance with a requirement variable, taking into account a determination specification. When in an overrun mode, a calibration is carried out and the speed of the pump is detected and is maintained during the calibration step. Once the triggering pressure for a calibration valve, arranged on the high-pressure side of the pump, has been reached, the pump current is detected and the determined speed and the determined pump current are used to calibrate the determination specification. A calibration in the overrun mode is performed without alteration to the speed of the fuel pump. This prevents a variable behaviour of the fuel pump which might produce undesired operating conditions.

A method for intelligent active engine braking using full authority active fuel management based on vehicle speed and brake pedal position. The method includes determining if the tow mode of the vehicle has been selected and enables all engine cylinders to ensure maximum engine braking capacity is available. When vehicle tow mode is not selected then the method varies engine braking capacity by disabling one or more cylinders based on the vehicle speed and brake pedal position.

An engine brake controller may obtain a performance characteristic of an engine. The engine brake controller may determine, based on the performance characteristic of the engine, that engine braking is enabled to control the engine. The engine brake controller may monitor a set of operating parameters of the engine. The engine brake controller may determine that operating values of the set of operating parameters satisfy corresponding thresholds of the set of operating parameters. The engine brake controller may determine, based on the operating values satisfying the corresponding thresholds, an engine braking configuration associated with activating engine braking of a set of cylinders of the engine. The set of cylinders may be a proper subset of a total quantity of cylinders of the engine. The engine brake controller may cause the engine braking to be applied to the set of cylinders to increase a temperature of exhaust gas from the engine.

A method for operating an engine in which fuel is supplied to the engine by a fuel pump and by a high-pressure fuel pump, and in which the speed of the fuel pump and/or the electrical current for feeding the fuel pump is controlled in accordance with a requirement variable, taking into account a determination specification. When the engine has changed to an overrun mode of operation, a calibration is performed and the speed of the fuel pump is detected and is maintained. Once the triggering pressure for a calibration valve has been reached, the pump current is detected, a bypass volumetric flow rate of the high-pressure fuel pump is determined during calibration using operating parameters and the triggering pressure for the calibration valve, the determined speed, the bypass volumetric flow rate and the determined pump current are used to calibrate the determination specification.

Transmission shocks and idling defects such as engine racing and rough idling due to aging of a throttle opening area are prevented from occurring. An internal combustion engine control apparatus for controlling an internal combustion engine that has an air flow rate sensor for measuring a rate of air represented as an actual air rate, the air flowing into a cylinder, and a throttle valve for adjusting the rate of air, includes a throttle valve controlling section for controlling a throttle opening of the throttle valve to reach a preset throttle opening set depending on a target air rate for realizing a demand torque, and a throttle opening correcting section for correcting the preset throttle opening on the basis of the target air rate upon fuel cutoff that stops a fuel from being supplied to the internal combustion engine and of an actual air rate measured by the air flow rate sensor.

A control system comprising a variable valve timing mechanism (B) able to set a closing timing of an intake valve (7), a fuel injector (13) for feeding fuel to a combustion chamber (5), an intake air amount detector (17) for detecting an amount of intake air fed to an intake passage from the outside air, and a pressure sensor (16) for detecting the pressure in the intake passage downstream of a throttle valve (16). When air in the combustion chamber (5) is blown back to the intake passage when injection of fuel is restarted after the fuel injection is stopped at the time of deceleration operation, the basis for calculation of the fuel injection amount in the initial cycle when fuel injection is restarted is switched from the amount of intake air detected by the intake air amount detector (17) to the pressure in the intake passage detected by the pressure sensor (18).

Methods and systems are provided for a boosted engine having a split exhaust system. In one example, a method comprises directing exhaust from a first cylinder group to one or more of a pre-compressor location, a post-compressor location, and an exhaust turbine, and directing exhaust from a second cylinder group to one or more of the pre-compressor location, and the exhaust turbine. Engine efficiency and knock control may be enhanced by directing exhaust gases to different locations based on engine operating conditions.