A direct injection fuel supply system, in one exemplary implementation, includes a lift fuel pump, a positive displacement pump, at least one fuel injector and an accumulator assembly. The lift pump is adapted to be in fluid communication with a supply of fuel and the positive displacement pump is in fluid communication with and downstream of the lift pump. The at least one injector is in fluid communication with an outlet of the positive displacement pump via a high pressure fuel line. The accumulator assembly includes an accumulator and a valve, where the valve is in direct fluid communication with the high pressure fuel line and the injector. The valve is selectively controlled to at least one of an open state providing fluid communication between the accumulator and the high pressure fuel line and a closed state blocking fluid communication between the accumulator and the high pressure fuel line.

A throttle device for controlling a fuel quantity to be supplied to a fuel injection nozzle includes a control chamber and a supply device for supplying fuel to the control chamber. The supply device includes an inlet throttle having a length selected such that a fuel flowing through the inlet throttle, when in operation, flows through the inlet throttle in a turbulent flow. An injection device including the throttle device is also provided.

A piston for an internal combustion engine includes a piston skirt and a piston crown attached to the piston skirt and including a combustion face. The combustion face forms a piston rim and a combustion bowl. A bowl edge defines an intersection of the combustion bowl and the piston rim, and a reentrant surface defining a reentrancy angle extends between the bowl edge and a bowl outer wall. A ratio of a bowl depth dimension coincident with the piston center axis to a compression height dimension coincident with the piston center axis is from about 0.30 to about 0.35.

A method is provided for pairing at least two injectors, e.g., two fuel injectors for a direct injection system of an internal combustion engine, wherein a criterion for the pairing of the at least two injectors is a total leakage and/or a pressure difference at a transfer pin of the respective injector. A method for producing an injector, e.g., a fuel injector for a direct injection system of an internal combustion engine, is also provided, wherein at least two instances of mechanical backlash, e.g., instances of pairing backlash, that are relevant to injection amounts, leakage amounts, and/or pressure differences of the injector are paired with each other.

Disclosed are multi-pulse fuel injection systems, control logic for operating such systems, and direct-injection engines having multi-pulse fuel delivery capabilities. A method is disclosed for operating the fuel injection system of an internal combustion engine (ICE) assembly. The method includes a vehicle controller transmitting command signals to the fuel injectors to inject a first pilot quantity of fuel (Q.sub.P1) and, subsequently, inject a second pilot quantity of fuel (Q.sub.P2), distinct from Q.sub.P1, after a first dwell time between Q.sub.P1 and Q.sub.P2 during a single combustion cycle of the ICE assembly. The vehicle controller also transmits command signals to the fuel injectors to inject a third pilot quantity of fuel (Q.sub.P3), greater than Q.sub.P1 and Q.sub.P2, after a second dwell time between Q.sub.P2 and Q.sub.P3, and then inject a fourth pilot quantity of fuel (Q.sub.P4), less than Q.sub.P3, after a third dwell time between Q.sub.P3 and Q.sub.P4 during the combustion cycle.

Methods are provided for controlling a direct injection fuel pump, wherein a solenoid spill valve is energized and de-energized according to certain conditions. A control strategy is needed to operate the direct injection fuel pump outside regions where pump operation may be variable and inaccurate, where the regions may be characterized by smaller pump commands as well as smaller displacement volumes. To maintain a suitable range of pump commands and displacements while operating outside the low accuracy regions, a method is proposed that involves clipping calculated pump commands when the calculated pump commands lie within the low accuracy regions.

A method of operating an internal combustion engine is provided. The method includes combusting a mixture of fresh air and fuel within multiple cylinders. The method also includes directing a first portion of exhaust gases into a first-stage turbine and a second-stage turbine of a turbocharger for expanding the exhaust gases, directing a second portion of exhaust gases from the exhaust manifold via an exhaust channel bypassing the first-stage turbine and recirculating a third portion of exhaust gases into an intake manifold after mixing with fresh air. The method includes controlling at least one of: reducing a normal engine speed at each engine power setting while maintaining constant engine power level by increasing a fuel injection per cycle; concurrently increasing a flow rate of the third portion of exhaust gas during recirculation; and advancing a fuel injection timing for reducing emission levels that meets Tier 4 requirements.

A fuel injector for operation with combustible gas, having a gas nozzle assembly having at least one gas nozzle opening, and at least one gas nozzle needle associated with the gas nozzle assembly and accommodated in an axial holder so that the stroke of the gas nozzle needle can be controlled. Each gas nozzle opening leads out of the holder having a radial direction component at the nozzle end. The fuel injector has, in the holder, a needle seat upstream of the particular nozzle opening, which needle seat is provided for selectively blocking a combustible-gas flow path to the associated gas nozzle opening in interaction with the gas nozzle needle. The gas nozzle openings are distributed over part of the circumference in the circumferential direction of the gas nozzle needle. The holder, adjoining the needle seat and extending away therefrom axially in the upstream direction, is asymmetric with respect to an axial center axis through the gas nozzle needle. The asymmetry results from a cross-section expansion of the holder on a side of the holder that lies radially opposite the gas nozzle opening, such that a greater mass flow rate of combustible gas can be conducted in the holder by the crosssection expansion than on the gas nozzle opening side opposite thereto. The holder is also shaped to apply a flow direction oriented toward the radially opposite gas nozzle opening, already upstream of the needle seat and via the cross-section expansion, to a combustible-gas flow guided to the needle seat by the cross-section expansion.

A vehicle includes a combustion engine having at least one cylinder to burn a fuel, and a fuel injector to supply a fuel mass to the at least one cylinder. The vehicle also includes a controller programmed to cause the fuel injector supply a series of fuel pulses that sum to an aggregate target fuel mass. The controller is also programmed to adjust a commanded duration of a subsequent pulse of the series of pulses from a target pulse duration value based on at least one of a dwell time since a preceding pulse, a fuel mass of the preceding pulse, and an opening delay of the preceding pulse.

A direct injection (DI) fuel supply system includes an accumulator valve coupled to a high pressure fuel line at a position between an accumulator and a fuel rail. A controller of the DI fuel supply system is configured to control the accumulator valve to maintain the pressurized fuel housed in the fuel rail at a desired pressure and to control the accumulator valve proximate a fuel injection event by a fuel injector such that the accumulator supplies the fuel rail with approximately the portion of the pressurized fuel injected by the fuel injector during the fuel injection event. This positioning of the accumulator valve between the DI positive displacement fuel pump and the fuel rail together with active control thereof also insulates the fuel rail and the fuel injector from fuel pressure pulsations generated by the DI positive displacement fuel pump.