Abstract: A method for determining a deviation of a fuel quality from a reference quality and for determining a change in exhaust gas emissions caused by this deviation by evaluating pressure waves in a fuel system of an internal combustion engine outfitted with one of a discontinuous fuel delivery and a fuel take-off.

Abstract: A method and device for monitoring a fuel metering system, in which fuel is pumped from a low-pressure zone into a high-pressure zone. The pressure in the high-pressure zone is detected. An error is recognized on the basis of the pressure variation in the high-pressure zone. The type of error is recognized on the basis of the shape of a pressure drop curve. The variation of the pressure quantity over time is approximated using a function such as the hyperbolic function. The type of error is recognized on the basis of the quantity characterizing the function.

Abstract: After an engine stop duration exceeds a predetermined time period (that is, if a decision outcome of S100 is positive), diagnosis of a leakage mechanism, which is a relief valve, for diagnosing the presence/absence of an abnormality is not performed during a current engine stop (S102). Therefore, even if the fuel pressure in the high-pressure fuel system is reduced to a low-pressure level due to temperature decrease as though fuel has been leaked in a state in which high-pressure fuel in a high-pressure fuel system cannot be leaked due to an abnormality in the relief valve, it generally occurs after the predetermined time period since such a decrease to a low-pressure level due to the temperature decrease is slow. Thus, an erroneous diagnosis as being normal is prevented from being made since the diagnosis has been suspended when the fuel pressure becomes equal to the low-pressure level.

Abstract: A water jet propulsion boat is constructed such that a fuel pressure detection device is free from a detection error or breakdown and a restart ability of an engine is protected against malfunction. A fuel tank is provided in a boat body of the water jet propulsion boat through vibration absorbing members. A fuel pump unit including a fuel pump is provided in the fuel tank. A fuel pressure sensor is provided in the fuel pump unit. An electric control device stops the fuel pump if the value detected by the fuel pressure sensor is out of the normal value range. Additionally, an electric control device stops operation of the fuel pump if the fall sensor detects the overturning of the boat body and if the detected value of the fuel pressure sensor is out of the normal value range. A regulator and a filter are provided to the fuel pump unit.

Abstract: In a method for testing the operation of a pressure sensing unit of an injection system of an internal combustion engine, the injection system has no high-pressure valve. An error is detected when a pressure gradient value falls below a pressure gradient limit while at the same time the most recently detected pressure is higher than a pressure limit.

Abstract: In a method for determining an uncontrolled acceleration of an internal combustion engine, a valve opening cross section is allocated to each load state of the internal combustion engine. In the event that a controller value is outside a limit range, an uncontrolled acceleration of the internal combustion engine is thereby detected.

Abstract: An engine control system comprises a model pressure determination module and a sensor diagnostic module. The model pressure determination module determines a modeled fuel rail pressure based on an injection duration of a fuel injector and a desired fuel mass injected by the fuel injector. The sensor diagnostic module generates a status of a fuel rail pressure sensor based on a comparison of the modeled fuel rail pressure and a sensed fuel rail pressure.

Abstract: A fuel injector which may be employed in injecting fuel into an internal combustion engine. The fuel injector includes an injector body and a head body formed to be separate from the injector body. The head body has installed therein a fuel pressure sensor working to measure the pressure of fuel in the fuel injector and is joined detachably to the injector body. The fuel injector alternatively includes an injector body and a fuel pressure-sensing unit equipped with a fuel pressure sensor. The fuel pressure-sensing unit is installed detachably on the injector body. This structure provides enhanced productivity of the fuel injector and facilitate the ease of replacement of the fuel pressure sensor.

Abstract: A diagnostic system includes a fuel pump module and a diagnostic control module. The fuel pump module activates a first pump when an engine is operating in a diagnostic mode. The first pump supplies fuel to fuel injectors of the engine via a fuel rail. The diagnostic control module receives a measured pressure signal from a pressure sensor that indicates a pressure of the fuel rail during the diagnostic mode. The fuel pump module sends at least one of a first and a second commanded fuel pressure signal to the first pump based on a predetermined relief pressure of a pressure relief valve. The diagnostic control module detects a fault of the pressure sensor based on an engine speed and a comparison between the measured pressure signal and at least one of the first commanded fuel pressure signal and a corrected relief pressure of the pressure relief valve.

Abstract: A diagnostic system for a pressure sensor includes a fuel pump module and a diagnostic control module. The fuel pump module activates a first pump and deactivates a second pump when an engine is operating in a diagnostic mode. The first pump supplies fuel to the second pump and the second pump supplies fuel to fuel injectors of the engine via a fuel rail. The diagnostic control module receives a measured pressure signal from a pressure sensor that indicates a pressure of the fuel rail during the diagnostic mode. The diagnostic control module detects a fault of the pressure sensor based on a comparison between the measured pressure signal and the commanded pressure signal for the first pump.

Abstract: In a fuel property detection device, a fuel housing is made of a thin-plate metal member that can be elastically-deformed by a fuel pressure in a fuel chamber. Thus, if the fuel pressure in the fuel chamber is increased, the fuel housing expands and the pressure in the fuel chamber is decreased. Further, if the fuel pressure in the fuel chamber is decreased, the fuel housing contracts and the pressure in the fuel chamber is increased. That is, the fuel housing functions as a kind of damper. Therefore, in the fuel property detection device, generation of abnormal noise due to fuel pulsation or the like, and a positional change of the electrodes due to the fuel pulsation or the like can be prevented.

Abstract: Systems and methods for performing leak testing on fuel system components in hybrid vehicles during engine-off operating conditions are disclosed. For example, a fuel tank may include a pressure accumulator which may be filled with fuel via a fuel pump in order to generate a vacuum which may be used to diagnose leaks in the fuel system.

Abstract: A testing device (10) for high-pressure injectors (50) of a common rail injection system of an engine unit, with the high-pressure injectors (50) each having a fuel return connection (52) for a fuel return line (54) is characterized by a throughflow quantity measuring/display unit (12) which can be detachably connected between the fuel return connection (52) and fuel return line (54).

Abstract: A diagnostic system comprises a monitoring module and a diagnostic module. The monitoring module receives a first rail pressure measured by a high side rail pressure sensor during engine cranking at a location where fuel is pressurized by a high pressure fuel pump. The diagnostic module selectively diagnoses a fault in at least one of the high pressure fuel pump and the high side rail pressure sensor when the first rail pressure is less than a predetermined pressure and rail pressures received during a predetermined period after the first rail pressure is received are less than the predetermined pressure.

Abstract: A fuel injector diagnostic system includes a fuel pump control module, a pressure sensor, and a diagnostic module. The fuel pump control module disables delivery of fuel to a fuel rail of an engine. The pressure sensor measures a first pressure of the fuel rail before an injection event and a second pressure of the fuel rail after the injection event on at least one of a plurality of injectors when the engine is running. The diagnostic module diagnoses a fault in the at least one of the injectors based on the first pressure and the second pressure.

Abstract: A fuel pressure sensor/sensor mount assembly in which a fuel pressure sensor is so mounted as to exposed to a high-pressure fuel path through which fuel is supplied to a fuel injector, a fuel injection apparatus equipped with a built-in fuel pressure sensor, and a pressure sensing apparatus working to measure the pressure of fuel in a fuel injector are provided. The fuel pressure sensor/sensor mount assembly is disposed between the high-pressure fuel path and the fuel injector, thus permitting the size of the fuel injector to be minimized without sacrificing the accuracy in measuring the pressure of the fuel. The fuel injection apparatus and the a pressure sensing apparatus are designed to ensure desired accuracy in measuring the pressure of the fuel.

Abstract: A method for detecting abnormality in a fluid supply line is provided that uses a fluid control apparatus with a pressure sensor so that abnormality of malfunction and sheet leaks of a plurality of valves incorporated into the fluid supply line can be checked easily, promptly and accurately by operating the flow rate control apparatus possessing the pressure sensor. Specifically, using a fluid supply line provided with the flow rate control apparatus possessing the pressure sensor equipped with a flow rate setting mechanism, a flow rate/pressure display mechanism, and/or a flow rate self-diagnosis mechanism, abnormality of the control valves, installed with the flow rate control apparatus and on the upstream side and downstream side thereof, is detected by using the pressure value displayed and/or the value diagnosed with a self-diagnosis mechanism of the flow rate control apparatus.

Abstract: A method and apparatus for identifying a component failure within a thermal regenerator operates as follows. The burner control unit monitors at least one of a fuel pump characteristic for a fuel pump and an ignition system characteristic for an ignition system. The fuel pump is used to supply fuel to a fuel-fired burner and the ignition system is used to ignite fuel supplied to the fuel-fired burner. The fuel pump characteristic is communicated to the burner control unit which compares the fuel pump characteristic to a predetermined fuel pump criteria. The ignition system characteristic is communicated to the burner control unit which compares the ignition system characteristic to a predetermined ignition system criteria. The burner control unit identifies a fuel pump failure when the fuel pump characteristic does not meet the fuel pump criteria, and identifies an ignition system failure when the ignition system characteristic does not meet the ignition system criteria.

Abstract: The invention provides, particularly although not exclusively in the context of a fuel injection system of a compression-ignition internal combustion engine, a method for detecting anomalous behaviour of a dynamic system (40), the method including i) determining a system model including plurality of characteristic parameters to define the dynamic system (40), ii) calculating one or more metrics indicative of the current system performance based on the plurality of characteristic parameters, iii) comparing the one or more derived metrics with one or more predetermined metrics indicative of anomalous system behaviour and iv) identifying a predetermined system fault condition if one or more of the derived metrics corresponds to one or more of the predetermined metrics. The invention also provides an apparatus for implementing the aforesaid method.

Abstract: A lift mechanism diagnostic system comprises a fuel pump disabling module, a pressure module, and a diagnostic module. The fuel pump disabling module selectively disables a fuel pump that is driven by a camshaft. The pressure module determines a first pressure of fluid provided to a variable valve lift mechanism when the variable valve lift mechanism is operated in a first lift mode while the fuel pump is disabled and determines a second pressure of the fluid when the variable valve lift mechanism is operated in a second lift mode while the fuel pump is disabled. The diagnostic module selectively diagnoses a fault in the variable valve lift mechanism based on the first and second pressures.

Abstract: A fuel injector for an internal combustion engine is provided. The fuel injector is equipped with a fuel pressure sensor, a sensor circuit such as an amplifier, and a valve actuator such as a piezoelectric actuator. The fuel injector also includes a conductive shield which is disposed between the sensor circuit and actuator drive terminals to supply electric power to the actuator and works to shield the sensor circuit from electric noises arising from the drive terminals, thereby minimizing the addition of the noises to an output of the fuel pressure sensor, as being processed in the sensor circuit, and ensuring the accuracy in determining the pressure of fuel based on the output of the fuel pressure sensor.

Abstract: A pressure-compensation unit, particularly for a tank-pressure sensor in a tank of a motor vehicle. The pressure-compensation unit includes a housing lid and a gas-permeable filter diaphragm, which covers an air hole. The pressure-compensation unit includes a cap-shaped cover element, which covers the filter diaphragm.

Abstract: A method for controlling a homogeneous-charge compression-ignition capable engine, operating with spray-guided spark ignition stratified combustion at low load, includes monitoring a speed of the engine, monitoring a load of the engine, determining a desired fuel pressure based upon the speed of the engine and the load of the engine, and utilizing the desired fuel pressure to control fuel injection into the engine, wherein the desired fuel pressure is calibrated to the speed and the load based upon increased stability of the engine at lower fuel pressures and lower soot emissions from the engine at higher fuel pressures.

Abstract: A diagnostic system and method for operating the same includes a pressure monitoring module generating a diagnostic pressure signal and a camshaft driven engine component correction module generating an engine component oil pressure correction signal and generating a corrected diagnostic pressure signal based on the diagnostic pressure signal and the engine component oil pressure signal. The system further includes a diagnostic module generating a failed variable valve lift mechanism signal based on the corrected diagnostic pressure signal.

Abstract: A fuel vapor pressure measuring device is provided, in a fuel supplying system, with a fuel tank for containing fuel, a fuel pump for supplying the fuel in the fuel tank to an injector, a fuel vapor generating section having a nozzle, a vaporizing chamber, and a venturi and vaporizing, in the vaporizing chamber, fuel by ejecting the fuel from the nozzle and causing the fuel to pass through the venturi, a first fuel path for interconnecting the fuel pump and the injector, a second fuel path having one end connected to the fuel pump and the other end connected to the fuel vapor generating section, a pressure sensor for detecting the pressure in the fuel vapor generating section, and an ECU for calculating the pressure of fuel vapor based on the result of detection by the pressure sensor. The fuel vapor generating section is mounted in the fuel tank.

Abstract: A method for determining fuel injection pressure or detecting a discrepancy in the fuel injection process of an internal combustion engine is provided. The engine includes a camshaft that actuates at least one fuel injector of the engine's fuel injection equipment. The method includes the step of determining a value T that is representative of the torque generated on the camshaft, such as the instantaneous torque or rotational speed of the camshaft, the torque being a resultant of accelerating and decelerating forces exerted on the camshaft by the at least one fuel injector during a phase of operation of the internal combustion engine. The method also includes the step of monitoring the value T for any increment, decrement or irregularity.

Abstract: A fuel system diagnostic module comprises a pressure module and a fault diagnostic module. The pressure module determines first and second pressures of a fuel rail of a fuel system at first and second times, respectively. The second time is after shutdown of an engine. The fault diagnostic module selectively diagnoses a fault in the fuel system based upon a comparison of a predetermined period with a period between the engine shutdown and the second time.

Abstract: A vehicle has a transmission, a transmission filter, and a controller having an algorithm or method for predicting the remaining useful life of the filter. The algorithm or method uses a sensor to detect an operating event of the transmission, such as a completed shift event or zero transmission output speed event, and increases a stored value of an accumulated distance and time variable. A shift sensor is operable for comparing a detected speed ratio of the transmission to a stored threshold speed ratio for determining the completed shift event. The remaining useful filter life is predicted using one or more look up tables using the values of the accumulated distance and time variables. The accumulated distance is calculated in part by dividing a prior recorded accumulated distance value by a ratio of an output speed of the transmission to an actual vehicle speed.

Abstract: A diagnostic system comprises a monitoring module and a diagnostic module. The monitoring module receives a first rail pressure measured by a high side rail pressure sensor during engine cranking at a location where fuel is pressurized by a high pressure fuel pump. The diagnostic module selectively diagnoses a fault in at least one of the high pressure fuel pump and the high side rail pressure sensor when the first rail pressure is less than a predetermined pressure and rail pressures received during a predetermined period after the first rail pressure is received are less than the predetermined pressure.

Abstract: An engine control system comprises a model pressure determination module and a sensor diagnostic module. The model pressure determination module determines a modeled fuel rail pressure based on a fuel pump flow rate and an engine fuel flow rate. The sensor diagnostic module generates a status of a fuel rail pressure sensor based on a comparison of the modeled fuel rail pressure and a sensed fuel rail pressure sensed by the fuel rail pressure sensor.

Abstract: A diagnostic system includes a fuel pump module and a diagnostic control module. The fuel pump module activates a first pump when an engine is operating in a diagnostic mode. The first pump supplies fuel to fuel injectors of the engine via a fuel rail. The diagnostic control module receives a measured pressure signal from a pressure sensor that indicates a pressure of the fuel rail during the diagnostic mode. The fuel pump module sends at least one of a first and a second commanded fuel pressure signal to the first pump based on a predetermined relief pressure of a pressure relief valve. The diagnostic control module detects a fault of the pressure sensor based on an engine speed and a comparison between the measured pressure signal and at least one of the first commanded fuel pressure signal and a corrected relief pressure of the pressure relief valve.

Abstract: A lift mechanism diagnostic system comprises a fuel pump disabling module, a pressure module, and a diagnostic module. The fuel pump disabling module selectively disables a fuel pump that is driven by a camshaft. The pressure module determines a first pressure of fluid provided to a variable valve lift mechanism when the variable valve lift mechanism is operated in a first lift mode while the fuel pump is disabled and determines a second pressure of the fluid when the variable valve lift mechanism is operated in a second lift mode while the fuel pump is disabled. The diagnostic module selectively diagnoses a fault in the variable valve lift mechanism based on the first and second pressures.

Abstract: A fuel pressure sensor/sensor mount assembly for use in a fuel injection system equipped with fuel injectors which inject fuel, as supplied from an accumulator through fuel pipes, into a multi-cylinder internal combustion engine mounted in an engine compartment of a vehicle. The assembly includes a connector unit and fuel pressure sensors. The connector unit has formed therein a plurality of communication paths each of which is to establish a connection between one of the fuel injectors and the accumulator through one of the fuel pipes. The connector unit also has formed therein sensor mounts exposed to the communication paths. Each of the fuel pressure sensors is disposed in the sensor mount to measure the pressure of the fuel in the communication path. This structure permits steps of installing the fuel pressure sensors within the engine compartment to be decreased and ensures desired measurement accuracy of the fuel pressure sensors.

Abstract: In a fuel property detection device, a fuel housing is made of a thin-plate metal member that can be elastically-deformed by a fuel pressure in a fuel chamber. Thus, if the fuel pressure in the fuel chamber is increased, the fuel housing expands and the pressure in the fuel chamber is decreased. Further, if the fuel pressure in the fuel chamber is decreased, the fuel housing contracts and the pressure in the fuel chamber is increased. That is, the fuel housing functions as a kind of damper. Therefore, in the fuel property detection device, generation of abnormal noise due to fuel pulsation or the like, and a positional change of the electrodes due to the fuel pulsation or the like can be prevented.

Abstract: Control method for an overpressure valve in a common-rail fuel supply system, the method including the phases of: delivering fuel under pressure, via a high-pressure pump, to a common rail equipped with the overpressure valve that is set to discharge the fuel present in the common rail into a discharge line when the fuel pressure inside the common rail exceeds a safety value; piloting, during a diagnostic test, the high-pressure pump to increase the fuel pressure inside the common rail beyond the safety value in order to trigger operation of the overpressure valve; determining, during the diagnostic test, the flow of the high-pressure pump and/or the fuel pressure inside the common rail; and comparing the flow of the high-pressure pump and/or the fuel pressure inside the common rail during the diagnostic test with respective threshold values.

Abstract: A method for determining a deviation of a fuel quality from a reference quality and for determining a change in exhaust gas emissions caused by this deviation by evaluating pressure waves in a fuel system of an internal combustion engine outfitted with one of a discontinuous fuel delivery and a fuel take-off.

Abstract: A fuel delivery device 11 has a delivery pipe 18, which supplies fuel to a fuel injection valve 21 of an internal combustion engine 10. An electromagnetic relief valve 22 releases the fuel from the delivery pipe 18 in response to an opening instruction and lowers the pressure of the fuel in the delivery pipe 18. A diagnosis device for the relief valve 22 has an electronic control unit 27 outputting the opening instruction to the relief valve 22 in response to a stopping instruction for stopping the engine 10. The unit 27 determines whether the relief valve 22 has a defect based on a manner in which the pressure of the fuel in the delivery pipe 18 changes after output of the stopping instruction. As a result, it is appropriately diagnosed whether the electromagnetic relief valve 22 has a defect.

Abstract: A fuel pressure sensor diagnosing device for diagnosing a fuel pressure sensor for detecting pressure in a common rail in which a high-pressure fuel to be supplied to an engine is accumulated, the device comprising: fuel temperature detection for detecting fuel temperature; and failure determination, provided with the fuel temperature detection for detecting fuel temperature via subsequent to stopping of the engine, for obtaining a resting and stabilization time between when the pressure in the common rail drops and when the pressure stabilizes on the basis of this detected fuel temperature, detecting a stabilized fuel pressure via the fuel pressure sensor subsequent to lapse of the resting and stabilization time, and determining a failure of the fuel pressure sensor when the detected stabilized fuel pressure exceeds a predetermined upper limit threshold value or is less than a predetermined lower limit threshold value.

Abstract: A method of controlling a motor vehicle is disclosed. The method can be used to determine an ambient pressure value without the use of an ambient pressure sensor. The ambient pressure value can be used for controlling a set of fuel injectors. The method can include provisions for adjusting the ambient pressure value to correct for errors introduced by engine wear and other factors.

Abstract: Method for detecting a cap off situation on the fuel tank of a combustion engine vehicle having a fill pipe head located under a fuel fill door, according to which a cap off test is run when the engine is started again after having been switched off and when a door switch indicates that the fuel fill door has been opened.

Abstract: A fuel filter assembly having a pressure sending unit for filtering and monitoring fuel and fuel pressure for diesel engines and the like comprising a filter head, a spin-on element and collection bowl. The filter head is fastened to an engine or other suitable structure by flange, bolts and supports the fuel filter assembly by monitoring fuel pressure by utilizing a pressure sending unit in fluid communication with an outlet port on the filter head. Preferably, filter head is a die cast head and includes therein typical inlet port, outlet port, and connected respectively thereto, inlet chamber and outlet chamber. Filter head is a generally circular structure having a flat annular mounting surface. The filter head may further comprises vent ports, vacuum switch ports or both, which are in fluid communication with outlet ports and return check valve ports that are in fluid communication with inlet ports.

Abstract: A pressure sensor senses a pressure of a fuel vapor system at a fuel vapor passage. An electronic control unit executes a post-depressurization period flow diagnosis to determine whether the fuel vapor passage is clogged based on a behavior of the pressure in the fuel vapor system, which is sensed with the pressure sensor in a sealed state of the fuel vapor system after introduction of a negative pressure into the fuel vapor system.

Abstract: Systems and methods for modulating fuel flow of a fuel delivery system including direct injection fuel injectors of an engine to mitigate engine noise are provided. An example of such systems may include a modulating device located in the fuel delivery system upstream of the direct injection fuel injectors, the modulating device configured to generate mitigating fuel pressure pulse(s) for attenuating fuel pressure pulse(s) generated by actuation of the direct injection fuel injectors. An example of such methods may include adjusting the modulating device responsive to actuation of the direct injection injectors, wherein operation of the modulating device is varied responsive to variation of direct injection fuel injector actuation.

Abstract: A fuel pressure sensor/sensor mount assembly in which a fuel pressure sensor is so mounted as to exposed to a high-pressure fuel path through which fuel is supplied to a fuel injector, a fuel injection apparatus equipped with a built-in fuel pressure sensor, and a pressure sensing apparatus working to measure the pressure of fuel in a fuel injector are provided. The fuel pressure sensor/sensor mount assembly is disposed between the high-pressure fuel path and the fuel injector, thus permitting the size of the fuel injector to be minimized without sacrificing the accuracy in measuring the pressure of the fuel. The fuel injection apparatus and the a pressure sensing apparatus are designed to ensure desired accuracy in measuring the pressure of the fuel.

Abstract: A fuel delivery device 11 has a delivery pipe 18, which supplies fuel to a fuel injection valve 21 of an internal combustion engine 10. An electromagnetic relief valve 22 releases the fuel from the delivery pipe 18 in response to an opening instruction and lowers the pressure of the fuel in the delivery pipe 18. A diagnosis device for the relief valve 22 has an electronic control unit 27 outputting the opening instruction to the relief valve 22 in response to a stopping instruction for stopping the engine 10. The unit 27 determines whether the relief valve 22 has a defect based on a manner in which the pressure of the fuel in the delivery pipe 18 changes after output of the stopping instruction. As a result, it is appropriately diagnosed whether the electromagnetic relief valve 22 has a defect.

Abstract: A diagnostic apparatus is combined with a high-pressure fuel supply system including a high-pressure fuel pump, a fuel rail, injectors, and a fuel pressure measuring unit for measuring fuel pressure in the fuel rail. The diagnostic apparatus is capable of detecting troubles in the high-pressure fuel pump and injectors and of discriminating between a trouble in the high-pressure fuel pump and a trouble in the injectors includes.

Abstract: A method and device for monitoring a fuel metering system, in which fuel is pumped from a low-pressure zone into a high-pressure zone. The pressure in the high-pressure zone is detected. An error is recognized on the basis of the pressure variation in the high-pressure zone. The type of error is recognized on the basis of the shape of a pressure drop curve. The variation of the pressure quantity over time is approximated using a function such as the hyperbolic function. The type of error is recognized on the basis of the quantity characterizing the function.

Abstract: In a hybrid vehicle of the invention, when a voltage level E of a low-voltage battery exceeds a preset alert reference value Eth1 (step S115), fueling control activates a negative pressure pump with a preset amount of power consumption for standard fuel vapor treatment (step S125). When the voltage level E of the low-voltage battery exceeds a low charge reference value Elow but is not higher than the preset alert reference value Eth1 (steps S115 and S120), the fueling control activates the negative pressure pump with a smaller amount of power consumption (step S130). When the voltage level E of the low-voltage battery is not higher than the low charge reference value Elow (step S120), the fueling control inactivates the negative pressure pump (step S135). Such control enables at least a voltage of the low charge reference value Elow to be reserved in the low-voltage battery even after regulation of internal pressure of a fuel tank.

Abstract: A system and method are provided for determining an ethanol content of a fuel that is part of a fuel and air mixture combusted within an internal combustion engine. A pressure characteristic of a fuel rail is monitored during operation of the engine. At least one of an effective bulk modulus of the fuel and a pressure perturbation signature is determined based on the pressure characteristic. The ethanol content is determined based on the at least one of the effective bulk modulus and the pressure perturbation signature.

Abstract: A method and a device for exciting pressure fluctuations in a fuel supply system of an internal combustion engine are provided, which in turn enable a determination of the sound velocity of the fuel. A quantity that characterizes the pressure in a fuel storage device or a fuel line is evaluated. In at least one operating state of the internal combustion engine, a natural oscillation of the fuel in the fuel storage device or the fuel line is excited.