A filter monitoring system and method are described. The filter monitoring system includes a module or circuit installed on an internal combustion engine or within a vehicle powered by the internal combustion engine. The filter monitoring system monitors the operation of the various filtration systems present on the engine to determine an amount of service life remaining and a loading percentage for various filter cartridges installed in the filtration systems of the internal combustion engine. The filter monitoring system determines the loading percentage and predicts remaining service life of a given filter cartridge via a time-based manner (e.g., based on the installation date of the filter cartridge and filter cartridge life specifications) and a pressure differential based manner (e.g., based on a determination of pressure drop across the filter cartridge).

A method of analyzing fuel component using an RF (Radio Frequency) sensor for a vehicle includes: receiving a new fuel into a fuel tank so as to mix existing fuel in the fuel tank with the new fuel, measuring a resonance frequency of the mixed fuel using an RF sensor, comparing the measured resonance frequency of the mixed fuel with a resonance frequency of a standard fuel, determining whether the mixed fuel is a normal fuel through the comparison, maintaining an engine combustion pattern corresponding to the standard fuel when the mixed fuel is a normal fuel, and operating reflecting an engine combustion control.

Methods and systems are provided for estimating ethanol content in fuel and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content and/or fuel age based on fuel temperature, a speed of sound in fuel, and an attenuation co-efficient of an ultrasonic signal in fuel. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content and fuel age.

A gaseous fuel supply system for an internal combustion engine may include a storage tank for storing liquefied gaseous fuel and supplying the fuel to the engine. The system may also include a liquid level sensor for measuring a level value of the liquefied gaseous fuel in the storage tank and a pressure sensor for measuring a pressure value of gaseous fuel in the fuel supply system. The system may further include a controller. The controller may be configured to: monitor a pressure signal of the pressure sensor indicating the pressure value and a tank level signal of the liquid level sensor indicating the level value; store the level value when the pressure value indicates the storage tank is empty; store the level value when the pressure value or the level value indicates the storage tank is full; and determine a calibrated level range based on the stored level values.

An increase control unit causes to apply a first voltage to a coil of a fuel injection valve to increase a driving current of the coil to a peak value. A holding control unit stops application of the first voltage, when the driving current increases to the peak value, and subsequently switches between a first holding control and a second holding control. The first holding control is to apply a second voltage lower than the first voltage to the coil based on at least one of the peak value, the second voltage, and a fuel pressure, to hold the driving current at a target current. The second holding control is to apply the first voltage to the coil to hold the driving current at the target current. The holding control unit performs one of the first holding control and the second holding control which is switched.

A lower limit setting portion of a fuel pump control system sets a lower limit value depending on an engine operating mode. For example, it sets a duty ratio of 0% as the lower limit value, when the engine operating mode is in a STOP mode in a turned-on condition of an ignition switch. A duty-ratio calculating portion carries out a feedback control in order that an actual fuel pressure comes closer to a target fuel pressure by use of the lower limit value and calculates a duty ratio for driving a fuel pump by the feedback control. An abnormal condition determining portion determines an abnormal condition based on the duty ratio and pump current. The abnormal condition determining portion further determines based on a remaining fuel amount whether the abnormal condition is caused by a disconnection or whether the abnormal condition is caused by an idling operation of the fuel pump due to fuel shortage.

A fuel injection apparatus for injecting fuel to an engine having cylinders, includes: injectors corresponding to the cylinders; a regulator for fuel pressure supplied to the injectors; and a processor. The processor performs: deciding to start a deposit removal for removing deposits adhering to injector-nozzles; and controlling each injector to inject fuel in a single injection mode for injecting one time or a divided injection mode for injecting multiple times in one combustion cycle and control the regulator based on engine operation condition. The controlling includes, when controlling each injector to inject fuel in the divided injection mode based on the engine operation condition, sequentially controlling each injector to reduce injection number in one combustion cycle when the deposit removal is decided to be started, and then controlling the regulator to increase fuel pressure.

A method of operating a fuel injector includes determining an actual energizing time correction value for a fuel injector at a first fuel rail pressure, calculating an extrapolated energizing time correction value by performing a mathematical calculation on the actual energizing time correction value, and controlling the operation of the fuel injector based on the actual energizing time correction value and the extrapolated energizing time correction value.

A lean operation fault detection and isolation (FDI) technique involves receiving, from a manifold absolute pressure (MAP) sensor, a measured MAP, detecting a lean operation fault where an engine is operating with a lean air/fuel ratio, estimating, using an observer, (i) an air/fuel ratio of an exhaust gas produced by the engine and (ii) the MAP, monitoring first and second residual values indicative of differences between (i) the estimated air/fuel ratio of the exhaust gas and a measured air/fuel ratio of the exhaust gas from an exhaust O2 sensor and (ii) the estimated MAP and the measured MAP from the MAP sensor, respectively, and, based on the monitoring of the first and second residual values, determining which of (i) an air intake of the engine, (ii) the exhaust O2 sensor, and (iii) a fuel injector of the engine is malfunctioning and causing the lean operation fault.

Provided is a method for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation. Pressurized fuel is intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion. An oxidation catalyst is arranged downstream said cylinders. The method comprises: determining the pressure in the fuel accumulator tank and whether said pressure is decreasing; and determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel. The method further comprises the steps of: determining whether the temperature associated with the oxidation catalyst is above a certain level and/or determining whether the air/fuel ratio is below a certain level and/or determining whether an amount of particulate matter is above a certain level; and confirming an unintended fuelling based on the determined conditions.