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 engine control device includes a model that, based on engine operating condition and first-type operation amount, reproduces at least one index from among various indexes of combustion state of engine, and a processor that executes a process including deciding on second-type operation amount, by optimization using the model so as to treat at least one of the indexes, which are reproduced by the model, as estimated value of control amount, and ensure that the estimated value of the control amount follows control target value, associating the second-type operation amount with the control target value and the engine operating condition, rewriting a learning control table in which operation amount corresponding to the control target value and the engine operating condition is registered, and calculating operation amount according to the learning control table based on the control target value and the engine operating condition.

An engine assembly comprising an internal combustion engine having a combustion chamber; an intake manifold for supplying air to the combustion chamber; a fuel injector for supplying fuel to the combustion chamber; an exhaust manifold for receiving exhaust gas released from the combustion chamber and a rotatable drive shaft, wherein combustion of fuel in air within the combustion chamber results in rotation of the drive shaft. The engine assembly further comprises a turbocharger system comprising a turbine and a compressor, wherein the turbine is configured to receive exhaust gas from the exhaust manifold, to recover energy from the exhaust gas, and to release the exhaust gas via a turbine outlet; and wherein the compressor is configured to receive energy from the turbine and thereby to compress air for use in combustion of fuel in the combustion chamber. An intake throttle valve is configured to selectively control a boost pressure by controlling supply of air to the intake manifold; and a bypass valve is configured to selectively divert exhaust gas from the exhaust manifold away from the turbine, wherein the bypass valve is controlled by the boost pressure. A controller is configured (a) to provide an intermediate value for desired valve position of the intake throttle valve based on a desired oxygen to fuel ratio; and (b) to output a final value for desired valve position of the intake throttle valve based on the intermediate value for desired valve position and an engine speed value.

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.

A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

An optimum engine configuration is determined, based on a predicted required power, for a seafaring vessel having a plurality of thrust engines. The predicted required power is determined by inputting vessel operational data, environmental data, and voyage data to a required power model. At least some of the vessel operational data and environmental data is received from a plurality of sensors positioned onboard the vessel. The optimum engine configuration is selected from a plurality of candidate engine configurations. Each candidate engine configuration includes a specified number of thrust engines running and a specified power output level of each thrust engine. The optimum engine configuration is selected based on a candidate total predicted fuel consumption of each candidate engine configuration. The candidate total predicted fuel consumption amount is determined as a sum of the engine-specific predicted fuel consumptions determined for each running thrust engine of that candidate engine configuration.

An operating method for a fresh-air feed device for an internal combustion engine is configured for feeding fresh air from the environment surrounding the internal combustion engine into at least one combustion chamber of the internal combustion engine. A controllable throttle valve is configured for varying a through-flowable area of the fresh-air feed device and for at least partially shutting off the fresh-air feed device. The device has a compressor which is arranged upstream of the throttle valve in an intended through-flow direction from the environment into the combustion chamber, which is configured for conveying an air mass flow in the intended through-flow direction in the fresh-air feed device. A pre-compressor section of the device is arranged upstream of the compressor, an intermediate section is arranged downstream of the compressor device and upstream of the throttle valve, and a post-throttle section is arranged downstream of the throttle valve. A first air pressure sensor is arranged in the pre-compressor section, and a second air pressure sensor is arranged in the post-throttle section. In a first operating state, a first air pressure is measured via the first air pressure sensor. In a second step in the first operating state, a second air pressure is measured via the second air pressure sensor. Based on the second air pressure, a theoretical air pressure for the intermediate section is ascertained in a manner dependent on a theoretically through-flowable area set by the throttle valve. The theoretical air pressure is compared with the first air pressure or with a comparison value for the first air pressure. In the event of a deviation of the theoretical air pressure from the first air pressure or from the comparison value beyond an error threshold value, a corrective value for the ascertainment of the theoretical air pressure is determined.

A skip fire control system for an engine of a vehicle includes a set of sensors configured to measure a set of operating parameters of the engine corresponding to a volumetric efficiency of the engine, a set of sub-systems having a set of operational states that affect transitions between different firing patterns/fractions of the engine, and a controller configured to, based on the set of operating parameters and the set of operational states of the set of sub-systems, determine a best firing pattern/fraction by taking into account losses or penalties to transition at least some of the set of operational states of the set of sub-systems to obtain a target firing pattern/fraction, and control the engine based on the target firing pattern/fraction to maximize an efficiency of the engine.

Systems, devices and methods for diagnosing malfunctioning in a crankcase ventilation (CCV) system are provided. A controller includes a processor and a memory storing instructions that cause the processor to: receive a plurality of pressure values including (i) a first pressure value indicative of a pressure of fluid flowing from a crankcase to a breather assembly of a system, (ii) a second pressure value indicative of a pressure of fluid flowing through a first tube coupled to the breather assembly, and (iii) a third pressure value indicative of a pressure of fluid flowing through a second tube coupled to the breather assembly; determine a pair of pressure differences based on the first pressure value, the second pressure value, and the third pressure value; and detect a malfunctioning in the CCV system based on the pair of pressure differences.

Methods and systems are provided for diagnostics of exhaust gas recirculation (EGR) components including an EGR pressure sensor. In one example, a method for an exhaust gas recirculation (EGR) system of a vehicle comprises diagnosing an excessive EGR flow rate via an MAP-MAF strategy, the MAP-MAF strategy including estimating an EGR flow rate based on a difference between an output of a manifold absolute pressure (MAP) sensor of the vehicle and an output of a mass airflow (MAF) sensor of the vehicle; and in response to stable intrusive conditions being met, intrusively commanding an EGR valve of the EGR system to a closed position to confirm the diagnosed excessive EGR flow rate. If the excessive flow is detected after the EGR valve is commanded to the closed position, a diagnostic code may be set.