An injector apparatus (310) for injecting fluid under pressure into an associated chamber (332) is provided. The injector apparatus (310) includes a first piston (314) defining a first working area facing an associated chamber (332), a high pressure piston (318) defining a high pressure working area facing a high pressure chamber (319), and a control piston (317) defining a control piston working area facing a control chamber (315). The first piston (314) is moveable with a body of the injector apparatus (310) to compress fluid in the high pressure chamber (319) using the high pressure piston (318), while movement of the first piston (314) is selectively controllable by controlling the fluid in the control chamber (315). The first working area is larger than the control piston working area and the control piston (317) working area is larger than the high pressure working area.

A method of adaptively predicting, during operation of a pump, a mass of fuel pumped by the pump during a pumping event to a fuel accumulator (“Q.sub.pump”) to control operation of the pump is provided, comprising: generating an adaptive model of operation of the pump, including estimating a start of pumping (“SOP”) position of a plunger of the pump, estimating Q.sub.pump, determining a converged value of the estimated SOP position, and determining a converged value of the estimated Q.sub.pump; using the adaptive model to predict Q.sub.pump by inputting to the model the converged value of the estimated SOP position, a measured pressure of fuel in the fuel accumulator and a measured temperature of fuel in the fuel accumulator; and controlling operation of the pump in response to the predicted Q.sub.pump.

The error diagnosis device has: an input unit that receives detected values for pressure inside the common rail; a calculation unit that, if the detected values are less than a target common rail pressure, calculates the pressure differences and the fuel pump discharge amounts; and a determination unit that determines whether or not a set time has lapsed in a state in which the pressure differences are at least a first threshold value and less than a second threshold value and the discharge amounts are at least a third threshold value and less than a fourth threshold value. The determination unit determines that an error has occurred in the high-pressure pump if the set time has lapsed and determines that an error has occurred in the flowrate adjustment valve if the set time has not lapsed.

A method of adaptively predicting, during operation of a pump, a mass of fuel pumped by the pump during a pumping event to a fuel accumulator (“Q.sub.pump”) to control operation of the pump is provided, comprising: generating an adaptive model of operation of the pump, including estimating a start of pumping (“SOP”) position of a plunger of the pump, estimating Q.sub.pump, determining a converged value of the estimated SOP position, and determining a converged value of the estimated Q.sub.pump; using the adaptive model to predict Q.sub.pump by inputting to the model the converged value of the estimated SOP position, a measured pressure of fuel in the fuel accumulator and a measured temperature of fuel in the fuel accumulator; and controlling operation of the pump in response to the predicted Q.sub.pump.

An injector apparatus (310) for injecting fluid under pressure into an associated chamber (332) is provided. The injector apparatus (310) includes a first piston (314) defining a first working area facing an associated chamber (332), a high pressure piston (318) defining a high pressure working area facing a high pressure chamber (319), and a control piston (317) defining a control piston working area facing a control chamber (315). The first piston (314) is moveable with a body of the injector apparatus (310) to compress fluid in the high pressure chamber (319) using the high pressure piston (318), while movement of the first piston (314) is selectively controllable by controlling the fluid in the control chamber (315). The first working area is larger than the control piston working area and the control piston (317) working area is larger than the high pressure working area.

A method of adaptively predicting, during operation of a pump, a mass of fuel pumped by the pump during a pumping event to a fuel accumulator (“Q.sub.pump”) to control operation of the pump is provided, comprising: generating an adaptive model of operation of the pump, including estimating a start of pumping (“SOP”) position of a plunger of the pump, estimating Q.sub.pump, determining a converged value of the estimated SOP position, and determining a converged value of the estimated Q.sub.pump; using the adaptive model to predict Q.sub.pump by inputting to the model the converged value of the estimated SOP position, a measured pressure of fuel in the fuel accumulator and a measured temperature of fuel in the fuel accumulator; and controlling operation of the pump in response to the predicted Q.sub.pump.

A method of adaptively predicting, during operation of a pump, a mass of fuel pumped by the pump during a pumping event to a fuel accumulator (“Q.sub.pump”) to control operation of the pump is provided, comprising: generating an adaptive model of operation of the pump, including estimating a start of pumping (“SOP”) position of a plunger of the pump, estimating Q.sub.pump, determining a converged value of the estimated SOP position, and determining a converged value of the estimated Q.sub.pump; using the adaptive model to predict Q.sub.pump by inputting to the model the converged value of the estimated SOP position, a measured pressure of fuel in the fuel accumulator and a measured temperature of fuel in the fuel accumulator; and controlling operation of the pump in response to the predicted Q.sub.pump.

The error diagnosis device has: an input unit that receives detected values for pressure inside the common rail; a calculation unit that, if the detected values are less than a target common rail pressure, calculates the pressure differences and the fuel pump discharge amounts, and a determination unit that determines whether or not a set time has lapsed in a slate in which the pressure differences are at least a first threshold value and less than a second threshold value and the discharge amounts are at least a third threshold value and less than a fourth threshold value. The determination unit determines that an error has occurred in the high-pressure pump if the set time has lapsed and determines that an error has occurred in the flowrate adjustment valve if the set time has not lapsed.

A fuel pump includes a pump head defining a barrel in which a plunger is slidable to pressurise fuel in a pumping chamber, and a fluid-inlet path through which fuel flows in to the pumping chamber under control of an inlet valve during a plunger return stroke. The plunger causes pressurisation of the fuel in the fluid-inlet path. The fuel pump may also include a fluid-outlet path through which fuel flows out of the pumping chamber, preferably under control of an outlet valve, during a plunger pumping stroke.

A fuel system is disclosed for use with an engine. The fuel system may have a common rail, a first type of fuel injector fluidly connected to the common rail, and a second type of fuel injector fluidly connected to the common rail. The second type of fuel injector may include a pumping portion having a bore formed therein, and a plunger reciprocatingly disposed in the bore. The second type of fuel injector may also include an accumulator portion fluidly connected to the common rail and configured to receive fuel pushed from the bore of the pumping portion by the plunger, a nozzle portion, and a valve portion fluidly connecting the pumping, nozzle, and accumulator portions.