Systems and methods are provided herein for tracking degradation of a high-pressure fuel pump. In one example, a fuel system controller is configured to receive an output pressure signal from a pressure sensor, transform the output pressure signal to the frequency domain to generate frequency content of the output pressure signal, and diagnose a condition of a fuel pump based at least in part on the frequency content of the output pressure signal, the fuel pump fluidly coupled to a fuel injector via a common fuel rail, and the fuel injector is operable to inject fuel to a cylinder of an engine.

Methods for controlling a Methods for controlling a valve disposed at an engine of a vehicle are disclosed. In one form of the disclosure, the method includes: determining whether an engine is an idle state; measuring a fuel pressure of the engine when the engine is the idle state; comparing the measured fuel pressure with a first threshold value; and operating the valve by applying a current to a valve operation coil when the measured fuel pressure is equal to or less than the first threshold value for a predetermined time or longer.

A method for operating an engine system 200 comprising an engine 208 configured to consume a fuel, having at least a two flowmeters 214, 216, is provided. The method includes the step of operating an engine 208 disposed between a supply flowmeter 214 of the at least two flowmeters and a return flowmeter 216 of the at least two flowmeters. A first fuel density in the supply flowmeter 214 and a second fuel density in the return flowmeter 216 are measured. The fuel density measurements 317 between the supply flowmeter 214 and return flowmeter 216 are compared and a differential density measurement value, Δρ 319, based on a difference in the second fuel density and the first fuel density is determined. The Δρ 319 is compared to a range of theoretical differential fuel density values, Δρ.sub.t, and potential fuel contamination is indicated if the Δρ lies outside a range of Δρ.sub.t values by a predetermined threshold.

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.

Systems and methods for reverse flow detection for a dual fuel engine are disclosed. The engine may include an intake manifold, a liquid fuel supply line and a gaseous fuel supply line, the gaseous fuel supply line including a gaseous fuel supply and a gaseous fuel rail. The method may include: receiving sensed values of gaseous fuel supply pressure, intake manifold pressure, and gaseous fuel rail pressure; determining a threshold value based on the sensed value of gaseous fuel supply pressure; determining a reverse flow in the gaseous fuel supply line based on the sensed values of gaseous fuel supply pressure and gas rail pressure and the determined threshold value; and outputting an indication of reverse flow in response to the determination of reverse flow.

Methods and systems are presented for diagnosing operation of passive grade vent valves of a fuel system. The methods and systems include adjusting a position of a vehicle so that fuel in a fuel tank may cause a first grade vent valve to open and a second grade vent valve to close.

An injection control device includes: an instruction output unit outputting an instruction energization time that is an instruction value of an energization time of a fuel injection valve corresponding to a target injection amount; an energization controller controlling energization of the fuel injection valve based on the instruction energization time; an area corrector correcting an area of an electric current flowing through the fuel injection valve when the fuel injection valve is driven by the electric current, calculating a correction time of the energization time, and correcting the instruction energization time; an abnormality determiner determining that an abnormality related to the area correction has occurred when the correction time reaches a predetermined upper limit value; and a normal-return determiner executing, after the abnormality determiner determines that the abnormality related to the area correction has occurred, a normal-return determination at an execution timing of when a degree of influence of the abnormality on an emission becomes equal to or less than a predetermined value, for determining whether or not an abnormal state in which the abnormality related to the area correction has been caused has returned to a normal state.

Methods and systems are provided for reducing hot fuel vapor formation in a port injection fuel rail. In one example, a method may include operating a dual fuel injection system with at least a calibrated minimum amount of port fuel injection over a wide range of engine operating conditions, even as conditions change. A direct fuel injection amount is adjusted in accordance.

The error diagnosis device has: an input unit that receives a downstream pressure value and an upstream pressure value, said downstream pressure value being detected on the downstream side of a fuel pump and said upstream pressure value being detected on the upstream side of the fuel pump; and a determination unit that, if the downstream pressure value is less than a preset first threshold value, determines whether or not the upstream pressure value is less than a preset second threshold value. The determination unit determines that an error has occurred further upstream than the fuel pump if the upstream pressure value is less than the second threshold value and determines that an error has occurred in the fuel pump if the upstream pressure value is at least the second threshold value.

A method to control a road vehicle during a slip of the drive wheels, which are caused to rotate by an internal combustion engine provided with a plurality of cylinders arranged in two banks, and with a plurality of fuel injectors each injecting fuel into a corresponding cylinder. The control method comprises the steps of: detecting a slip of at least one drive wheel; and controlling the internal combustion engine, only during a slip of at least one drive wheel, with a signalling law, which causes the internal combustion engine to work in an abnormal manner so as to generate an abnormal vibration and/or an abnormal noise, which can be perceived by the driver. The internal combustion engine has two twin control units, each of which is associated with a corresponding bank, controls all and the sole injectors of its own bank and actuates the signalling law completely independently of and autonomously from the other control unit.