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.

A control apparatus includes a throttle configured to adjust an amount of air flowing in an intake passage of an engine, an accelerator opening sensor configured to detect an accelerator opening, a throttle opening sensor configured to detect an opening of the throttle, and a control unit configured to control the opening of the throttle. The control unit includes a setting unit configured to set a target opening and set a control amount of the throttle based on a deviation between the target opening and the opening detected by the throttle opening sensor, and a correction unit configured to, if the target opening is not more than a predetermined opening, set a correction amount of the control amount such that the opening of the throttle becomes large independently of the deviation.

Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method uses the engine to generate larger amounts of thermal energy while the engine is rotated under power of an electric machine. The systems and methods described herein may be applied to series and parallel hybrid vehicles.

A self-calibration method of determining remaining useful life of an internal combustion engine's air filter includes establishing a pressure drop versus mass airflow rate relationship for a clean air filter using pressure drop, mass airflow rate, and temperature data captured at low and elevated engine speeds. The method also includes establishing a maximum clean air filter pressure drop at a preset maximum airflow using the clean filter relationship. The method additionally includes establishing a pressure drop versus mass airflow rate relationship for an in-service air filter using pressure drop, mass airflow rate, and temperature data captured at low and elevated engine speeds. The method also includes determining a maximum in-service air filter pressure drop at the preset maximum airflow using the in-service filter relationship. The method further includes comparing the maximum clean and in-service air filter pressure drops to determine the remaining useful life of the in-service air filter.

Systems and methods are provided for diagnosing cylinders in an engine. In one example, the method may include while receiving first feedback from a vibration sensor coupled to a first cylinder of the engine, perturbing the first cylinder during engine operation. Responsive to the first feedback indicating a first vibration level difference greater than or equal to a first threshold difference, a first indication of a first degradation condition of the first cylinder may be set, and thereafter the engine may be operated based on whether or not the first indication was set.

Provided is a control device of a vehicle including an alternator that generates power using a driving force of an internal combustion engine, wherein when the alternator is cold and a request power of an accessory is equal to or greater than a predetermined value, the control device increases the number of revolutions of the internal combustion engine compared with the number of revolutions when the alternator is not cold.

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.

Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

Provided is a signal processing device capable of effectively reducing a work load of a parameter setting operator in response to an increase in parameters constituting complicated filter control. Therefore, in the signal processing device filters an output signal from a sensor mounted on a vehicle, setting is made with respect to a plurality of filters having different filter types or filter coefficients for setting a filter characteristic of a cutoff frequency or a pass band, an individual code is set for each of the plurality of filters, and the signal processing device includes a CPU that selects the individual code based on an engine operating state so that a corresponding filter is selected, and processes an output signal from the sensor using the filter that has been selected.

A CPU determines that misfires are occurring in a cylinder subject to determination of whether misfires are occurring when a value obtained by subtracting a rotation fluctuation amount ΔT30[n−2] from a rotation fluctuation amount ΔT30[n] is greater than or equal to a determination threshold. The rotation fluctuation amount ΔT30[n] is subject to the misfire determination. The rotation fluctuation amount ΔT30[n−2] is 360° CA earlier than the rotation fluctuation amount ΔT30[n]. When stopping fuel supply to a cylinder #1 and determining whether misfires are occurring in cylinder #4, the CPU determines whether misfires are occurring after executing a correcting process that corrects the determination threshold to a second determination threshold Δth2, which is less than a first determination threshold Δth1.