Abstract: Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a port injection fuel rail and high variable fuel pressure at a direct injection fuel rail. Port injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. High pressure port injection may be advantageously used to provide fuel at high pressure during conditions when fuel delivery via high pressure direct injection is limited.

Abstract: Methods and systems are providing for improving zero flow lubrication (ZFL) of a high pressure fuel pump coupled to direct fuel injectors via a direct injection fuel rail. A ZFL transfer function for the fuel pump is learned while fuel is at non-nominal fuel bulk modulus conditions and corrected for variations from a nominal fuel bulk modulus estimate. When zero flow lubrication of the pump is requested, the pump is operated with a duty cycle based on the learned transfer function and an instantaneous estimate of the fuel bulk modulus to compensate for differences in fuel condition from the nominal fuel bulk modulus estimate.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, fuel is supplied to port fuel injectors and direct fuel injectors via a same high pressure fuel pump, and high pressure port fuel injection is activated at times where direct fuel injection would supply less fuel than is desired or an inconsistent amount of fuel.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from a direct fuel injector are disclosed. In one example, a transfer function or gain of a direct fuel injector is adjusted in response to an exhaust lambda value and a first pulse width of two pulse widths provided to an injector of a cylinder during a cylinder cycle.

Abstract: Systems and methods are provided for a high-pressure fuel pump to mitigate audible ticking noise associated with opening and closing of a digital inlet valve of the high-pressure pump. To reduce the ticking noise associated with the high-pressure pump when the engine is idling, a solution is needed that is simple and does not involve retrofitting the fuel system with noise, vibration, and harshness countermeasures to mask the noise. Pressure devices and associated operation methods are provided that involve adding a combination of several check valves, an accumulator, and a flow control valve with weep channels to allow the digital inlet valve to be deactivated during engine idling as defined by a threshold engine speed.

Abstract: Methods and systems are providing for improving zero flow lubrication (ZFL) of a high pressure fuel pump coupled to direct fuel injectors via a direct injection fuel rail. A ZFL transfer function for the fuel pump is learned while fuel is at non-nominal fuel bulk modulus conditions and corrected for variations from a nominal fuel bulk modulus estimate. When zero flow lubrication of the pump is requested, the pump is operated with a duty cycle based on the learned transfer function and an instantaneous estimate of the fuel bulk modulus to compensate for differences in fuel condition from the nominal fuel bulk modulus estimate.

Abstract: Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a first direct injection fuel rail and high variable fuel pressure at a second direct injection fuel rail. The direct injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. Fixed and variable high pressure direct injection may be advantageously used to provide learn the ballistic region of each direct injector.

Abstract: Various systems and methods are described for diagnosing injector variability in a dual fuel, multi-injector system. In one example, a single injector in one cylinder is enabled while remaining cylinders are fueled with a first fuel and subsequently, a second fuel is injected via the enabled injector into the one cylinder in a predetermined sequence and fuel rail pressure drops are measured. Further, measured pressure drop after each injection event is corrected for an increase in injector closing delay.

Abstract: Methods and systems are provided for closed loop operation of a high pressure fuel pump connected to the direct injectors of an internal combustion engine. During operation of the high pressure pump a dead zone may exist where a substantial change in the pump duty cycle does not correspond to a substantial change in the fuel rail pressure. To operate outside the dead zone, a relationship between the pump duty cycle and fuel rail pressure is learned upon completion of several pump and engine conditions, thereby improving high pressure pump operation and reducing pump degradation.

Abstract: Methods and systems are provided for pressurizing a step chamber of a direct injection fuel pump. In one example, the step chamber may be pressurized to a pressure higher than an output pressure of a lift pump, the lift pump supplying fuel to the direct injection fuel pump. The pressurization of the step chamber may occur during at least a portion of a pump stroke of the direct injection fuel pump.

Abstract: Methods and systems are provided for delivering fuel to a port injector fuel rail in a port fuel direct injection (PFDI) engine. In one example, the port injector fuel rail may receive fuel from each of a compression chamber and a step chamber of a direct injection fuel pump coupled in the PFDI engine. In this way, pressurized fuel may be supplied to the port injector fuel rail during an entire cycle of the direct injection fuel pump.

Abstract: Methods are provided for detecting high pressure pump bore wear, wherein wear between a piston and bore of a pump may cause an excessive amount of fuel to leak out of a compression chamber of the pump. A reliable method is needed that involves a pump performance model that incorporates a number of physical effects and is verified by real high pressure pump test data. A method is proposed that involves comparing a target pump rate based on the pump performance model to a real fuel injection rate in order to determine if an abnormal amount of fuel may be leaking from the high pressure pump.

Abstract: Methods are provided for correct spill valve timing of a high pressure pump coupled to the direct injection system of an internal combustion engine. A method is needed to monitor and adjust spill valve timing on-board the vehicle, where spill valve timing error may result from sensors error and/or time between command signal and actuation response of the spill valve. To self-correct spill valve timing error on-board a vehicle, methods are proposed that involve monitoring and recording fuel rail pressures, high pressure pump duty cycles, and fractional liquid volume pumped values in order to find zero flow relationships.

Abstract: Methods and systems are provided for a direct injection fuel pump. The methods and system control pressure within a compression chamber so as to improve fuel pump lubrication.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, a transfer function or gain of a direct fuel injector is adjusted in response to an exhaust lambda value and a fraction of fuel supplied to a cylinder during a cylinder cycle.

Abstract: Methods and systems are providing for improving zero flow lubrication (ZFL) of a high pressure fuel pump coupled to direct fuel injectors via a direct injection fuel rail. A ZFL transfer function for the fuel pump is learned while fuel is at non-nominal fuel bulk modulus conditions and corrected for variations from a nominal fuel bulk modulus estimate. When zero flow lubrication of the pump is requested, the pump is operated with a duty cycle based on the learned transfer function and an instantaneous estimate of the fuel bulk modulus to compensate for differences in fuel condition from the nominal fuel bulk modulus estimate.

Abstract: Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a port injection fuel rail and high variable fuel pressure at a direct injection fuel rail. Port injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. High pressure port injection may be advantageously used to provide fuel at high pressure during conditions when fuel delivery via high pressure direct injection is limited.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, fuel is supplied to port fuel injectors and direct fuel injectors via a same high pressure fuel pump, and high pressure port fuel injection is activated at times where direct fuel injection would supply less fuel than is desired or an inconsistent amount of fuel.

Abstract: Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a first direct injection fuel rail and high variable fuel pressure at a second direct injection fuel rail. The direct injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. Fixed and variable high pressure direct injection may be advantageously used to provide learn the ballistic region of each direct injector.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, a transfer function or gain of a direct fuel injector is adjusted in response to an exhaust lambda value and a fraction of fuel supplied to a cylinder during a cylinder cycle.