A method for controlling fuel injection to an engine may include calculating an amount of air passing through a throttle, which is actually controlled, from a calculated amount of air in an intake manifold, which is calculated from a pressure value detected by a pressure sensor installed in the intake manifold connecting the throttle and a cylinder to each other, and a calculated pressure change in the intake manifold. The method may further include predicting an actual amount of air to be sucked into the cylinder when mixed with fuel from the calculated amount of air in the intake manifold and the calculated amount of air passing through the throttle. The method may also include injecting an amount of fuel according to the predicted actual amount of air to be sucked into the cylinder.

An electric assist turbocharger unit for use in an internal combustion engine, comprising a shaft configured for torque-transmittingly connecting a compressor to a turbine of the turbocharger unit and an electric motor configured for rotatably actuating the shaft in a first rotational direction and in an opposed second rotational direction. The engine includes an aftertreatment system, and the rotation of the shaft is designed to retard the flow of intake air through an intake passage and of exhaust gases through the aftertreatment system, thereby controlling the temperature in the aftertreatment system.

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 system for forming a negative pressure in a negative pressure reservoir of a brake system includes, an engine having an intake manifold and a camshaft, a vacuum pump connected to the camshaft through a clutch device and generating a pump negative pressure, a turbocharger having a compressor supplying a compressed air to the engine, a pump negative pressure line connecting the vacuum pump and the negative pressure reservoir and supplying the pump negative pressure to the negative pressure reservoir, an intake negative pressure line connecting the negative pressure reservoir and the intake manifold and supplying the intake negative pressure of the intake manifold to the negative pressure reservoir, and a negative pressure source selection apparatus configured to control opening and closing of the pump negative pressure line and the intake negative pressure line based on operation of the turbocharger.

A regulating method for a charged internal combustion engine, wherein an operating point of the compressor is adjusted in a compressor map by a compressor position regulator based on a throttle valve regulation deviation in that both a first manipulated variable for actuating the compressor bypass valve as well as a second manipulated variable for actuating the turbine bypass valve are calculated by the compressor position regulator. The operating point of the compressor is corrected by a correction regulator on the basis of an air mass regulation deviation in that both a first correction variable for correcting the first manipulated variable as well as a second correction variable for correcting the second manipulated variable are calculated by the correction regulator.

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.

Engine controllers and control schemes are provided for managing engine state transitions requiring increased compressor pressure ratios in turbocharged engines. In some circumstances, turbo lag can be mitigated by initially transitioning the engine to an intermediate engine state that directly or indirectly increases airflow through the engine and turbocharger relative to what would be possible if the engine were immediately commanded to operate at the target engine state. After reaching a point where the desired torque is actually generated at the intermediate engine state, the operational settings are gradually reduced to the target effective firing density while increasing the operational compressor pressure ratio to the target compressor ratio.

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.

Various methods and systems are provided for controlling emissions and a likelihood of engine knock during combustion in a multi-fuel engine. A method for an engine includes mixing an amount of a first fuel and an amount of a second fuel to combust a fuel mixture having a fuel ratio of the first fuel relative to the second fuel, the first fuel having a faster combustion flame speed relative to the second fuel, the fuel mixture having an air-to-fuel ratio with an amount of air delivered to the engine. The method further includes controlling either or both of a speed of combustion and a stability of combustion of the fuel mixture with the amount of air delivered to the engine by changing at least one of the fuel ratio, the air-to-fuel ratio, or both of the fuel ratio and the air-to-fuel ratio.

Timing of HHO gas injection into a 4-stroke engine is optimized based on engine operating parameters to improve fuel economy.