A method and system is provided for correcting fueling commands. For example, the method and system may calibrate an engine operating in a steady-state mode by determining a plurality of accuracy errors associated with a fueling rate based on a plurality of sensor measurements. The method and system may determine fueling rate correction data during on-line operation of the engine based on the plurality of accuracy errors. The on-line operation of the engine may comprise operating the engine in a transient mode at a first period of time and a steady-state mode at a second period of time. The method and system may control at least one fueling valve during operation of the engine using a corrected fueling command. The corrected fueling command is based on the fueling rate correction data.

An engine system including a fuel system control arrangement includes an internal combustion engine including an exhaust line, one or more cylinders, and one or more fuel injectors corresponding to the one or more cylinders, means for determining fresh air mass flow into an intake to the engine, a nitrogen oxide (NOx) sensor in the exhaust line, and a controller configured to determine oxygen (O2) in exhaust gas based on a signal from the NOx sensor and to calculate a current fuel injection quantity based on the O2 in the exhaust gas and determined fresh air mass flow into the intake, to compare the current fuel injection quantity to a theoretical fuel injection quantity under current operating conditions, and to adjust an amount of fuel injection from the one or more fuel injectors when the current fuel injection quantity differs from the theoretical fuel injection quantity to make the current fuel injection quantity closer to the theoretical fuel injection quantity.

A catalyst degradation detection apparatus includes an air-fuel ratio detector disposed downstream of a catalyst and configured to detect an air-fuel ratio of exhaust gas flowing out from the catalyst, and an electronic control unit configured to control an air-fuel ratio of inflow exhaust gas flowing into the catalyst and determine whether the catalyst is degraded. The electronic control unit is configured to execute degradation determination control that brings the air-fuel ratio of the inflow exhaust gas to an air-fuel ratio leaner or richer than a stoichiometric air-fuel ratio. The electronic control unit is configured to determine whether precious metal of the catalyst is degraded based on the air-fuel ratio detected by the air-fuel ratio detector when an oxygen storage amount of the catalyst is varying in the degradation determination control.

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.

An embodiment is a method including controlling a purge fuel amount of an active purge system (APS), the controlling including correcting the purge fuel amount using a primary weighting factor obtained using an ambient air temperature and a hydrocarbon (HC) concentration in purge gas fuel as input values, and correcting the corrected purge fuel amount using a secondary weighting factor due to a purge learning value. Some embodiments further include controlling of the purge fuel amount applies a purge execution condition, and the purge execution condition on the basis of a negative pressure of an intake manifold and a vehicle speed of the vehicle in which a purge flow rate exhibits as being greater than or equal to a predetermined value.

Generators and methods for shutting down generators in confined spaces. One generator includes an internal combustion engine, an alternator, a power outlet, and an electronic processor communicatively coupled to the engine. The electronic processor is configured to obtain an engine speed of the engine, and determine that the engine speed is below an engine speed threshold. The electronic processor is further configured to determine, in response to determining that the engine speed is below the engine speed threshold, that a predetermined number of a plurality of secondary parameters of the generator have crossed respective secondary thresholds. The electronic processor is further configured to shut down the generator in response to determining that the predetermined number of the secondary parameters have crossed the respective second thresholds.

In a case where an internal combustion engine is executing an all-cylinder operation to operate all cylinders, an air-fuel ratio estimation part of an ECU 1 estimates an air-fuel ratio of each of the cylinders by using a first observer. On the other hand, in a case where the internal combustion engine is executing a cylinder-cut operation to rest a part of the cylinders and to operate other of the cylinders, the air-fuel ratio estimation part does not estimate the air-fuel ratio of each of the cylinders by using the first observer.

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

Methods and systems include determining a cylinder air-fuel ratio imbalance in a multi-cylinder engine. In one example, the method may include sequentially firing an engine cylinder to provide an expected air-fuel deviation and learning cylinder air-fuel ratio imbalance based on an error between an actual air-fuel ratio deviation from a maximum lean air-fuel ratio relative to an expected air-fuel deviation during a deceleration fuel shut-off event.

Methods and systems are provided for learning fuel injector error for cylinder groups during a deceleration fuel shut-off (DFSO), where all cylinders of an engine are deactivated, sequentially firing each cylinder of a cylinder group, each cylinder fueled via consecutive first and second fuel pulses of differing fuel pulse width from an injector. Based on a lambda deviation between the first and second pulses, a fuel error for the injector and an air-fuel ratio imbalance for each cylinder is learned. Alternatively or additionally, a difference in crankshaft acceleration between the first and second pulses relative to the expected deviation may be used to learn torque error, and adjust fuel injector error and air-ratio imbalance for each cylinder.