Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/22—Safety or indicating devices for abnormal conditions
  • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/22—Safety or indicating devices for abnormal conditions
  • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
  • F02D2041/223—Diagnosis of fuel pressure sensors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/06—Fuel or fuel supply system parameters
  • F02D2200/0602—Fuel pressure
  • F02D2200/0604—Estimation of fuel pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
  • F02D41/187—Circuit arrangements for generating control signals by measuring intake air flow using a hot wire flow sensor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/3809—Common rail control systems
  • F02D41/3836—Controlling the fuel pressure

Definitions

• the present invention relates to a device for monitoring the fuel pressure in the fuel supply circuit of a fuel injection heat engine.
• the present invention relates to a device for monitoring the fuel pressure in the fuel supply circuit of a fuel injection heat engine.
• fuel injection In known devices as described for example in US Pat. Nos. 6,032,639 and 6,138,638, the pressure of the fuel in the fuel supply circuit of injection heat engines is generally measured by a pressure sensor. The value of this pressure is converted into an electrical signal which is used by a computer which manages the engine operation control units. Such pressure sensors are always present in direct injection engines.
• the object of the present invention is to provide a device for monitoring the fuel pressure in the fuel supply system of a heat engine, which can remedy the possible failure of the fuel pressure sensor when such a sensor is present or replace such a sensor to ensure optimal operation of the engine.
• the subject of the invention is a device for monitoring the fuel pressure in the fuel supply circuit of a fuel injection thermal engine which comprises at least one cylinder and a gas exhaust pipe combustion, said device comprising, - means for generating a measurement value of the richness of the exhaust gases in said exhaust duct, - means for generating a measurement value of the flow rate of fresh air admitted into said cylinder, - means determining the duration of mechanical opening of said injector, and - calculation means for determining a reconstituted value of fuel pressure from said measurement value of the richness of the exhaust gases, said measurement value of the flow of fresh air and of said duration of mechanical opening of said injector.
• the invention also relates to a method for monitoring the fuel pressure in the fuel supply circuit of a fuel injection thermal engine which comprises at least one cylinder and a flue gas exhaust pipe, comprising the following steps: - generation of a measurement value of the richness of the exhaust gases in said exhaust duct, - generation of a measurement value of the flow of fresh air admitted into said cylinder, - determination of the duration of mechanical opening of said injector, and - determination of a reconstituted value of fuel pressure from said measurement value of the richness of the exhaust gases, said measurement value of the fresh air flow rate and said duration of mechanical opening of said injector.
• the method according to the invention may also include one or more of the following steps: - determination of the value of the mass of fuel injected from said measurement value of the richness of the exhaust gases and from said measurement value of the fresh air flow rate, determination of the value of the static flow rate of the injector as a function of said value of the mass of fuel injected and said duration of mechanical opening of the injector and determination of said reconstituted value of pressure from said static injector flow and the pressure value near the nozzle nose.
• FIG. 1 is a simplified diagram of the device according to the invention in the case of a direct injection fuel supply system comprising a pressure sensor
• FIG. 2 is a simplified diagram of the device according to the invention in the case of an indirect injection fuel supply system, devoid of a pressure sensor
• FIG. 1 is a simplified diagram of the device according to the invention in the case of a direct injection fuel supply system comprising a pressure sensor
• FIG. 2 is a simplified diagram of the device according to the invention in the case of an indirect injection fuel supply system, devoid of a pressure sensor
• FIG. 1 is a simplified diagram of the device according to the invention in the case of a direct injection fuel supply system comprising a pressure sensor
• FIG. 2 is a simplified diagram of the device according to the invention in the case of an indirect injection fuel supply system, devoid of a pressure sensor
• FIG. 1 is a simplified diagram of the device according to the invention in the case of a direct injection fuel supply system comprising a pressure sensor
• FIG. 2 is a simplified diagram of the device according to
• FIGS. 1 and 2 represent a device for monitoring the fuel supply circuit of an engine, in which for the sake of simplification, a single cylinder 2 has been shown with its associated injector 4. In a known manner, such a device monitoring includes a computer 1 which determines the optimal operating parameters of the heat engine from data measured by different sensors.
• the computer 1 comprises means 10 for controlling the injectors which determine the control parameters for each injector 4, in particular the duration of electrical control of the injector, which is the duration of control of the electrical actuator, by example the coil of each injector.
• the reference 5 designates the air intake duct into the combustion chamber of the cylinder 2 and the reference 6 designates the exhaust duct for the combustion gases.
• the reference 7 designates the fuel supply circuit which supplies the cylinder 2 via the injector 4.
• the fuel is injected directly into the combustion chamber by the injector 4.
• the injection is indirect and the fuel is injected into the intake duct 5.
• the device for monitoring the fuel pressure in the fuel supply circuit of the heat engine comprises means 8 for measuring the richness of the exhaust gases and means 9 for measuring the flow of fresh air admitted into the cylinder 2.
• the means 8 for measuring the richness of the exhaust gases are for example produced in the form of a oxygen, delivering a signal (an analog voltage) depending on the oxygen rate, oxygen rate from which the richness of the exhaust gases can be determined.
• the means 9 for measuring the flow of fresh air admitted into the cylinder 2 are produced for example in the form of a mass air flow meter or in the form of a pressure sensor delivering a measurement of the air pressure from which the flow air can be replenished taking into account the engine speed.
• the monitoring device further comprises calculation means 12 for reconstituting by calculation the real fuel pressure from the measurements made by said means 8 and 9, and from the duration of mechanical opening of the injector.
• a fuel pressure value in the fuel supply circuit is calculated from the measurement value of the richness of the exhaust gases, from the measurement value of the fresh air flow admitted into the cylinder and the mechanical opening time of the injector.
• the calculation means 12 thus comprise: means for determining the value of the mass of fuel injected from the measurement value of the richness of the exhaust gases and from the measurement value of the fresh air flow admitted into the cylinder, - means for determining the value of the static flow rate of the injector as a function of the value of the mass of fuel injected and the duration of mechanical opening of the injector, - means for determining the reconstituted value of pressure from said static injector flow and the value of the pressure near the nozzle nose.
• Q ⁇ (2) a where Qs is the static flow rate of the injector (in g / s), d is the duration of mechanical opening of the injector (in ms) and Me is the mass of fuel injected (in mg /stroke) ; Q ⁇ Pc -Pa (3) QsO V ⁇ P0 or, where Pc is the reconstituted value of pressure (in bar), Qs is the static flow rate of the injector (in g / s), and Pa is the value of the pressure near the nose of the injector (in bar),
• QsO being the nominal static flow rate of the injector (in g / s) for a nominal value ⁇ PO of the difference between the fuel pressure and the pressure near the nozzle nose (in bar).
• the value Pa of the pressure near the nose of the injector can for example be determined by measurement by means of a sensor, which can be the same as that which is used to determine the air flow admitted by the engine.
• FIG. 3 represents the variation curve C1 of the quantity of fuel Me (in mg / stroke) delivered by the injector as a function of the duration d1 (in ms) of electrical control, for a constant value of the difference between the pressure fuel pressure and air pressure near the nozzle nose.
• This variation curve C1 is essentially a straight line whose slope Qs represents the static flow rate of the injector (in g / s). However, for the low values of d1, the curve has a non-linear part A which is not shown. The extension of the linear part intersects the abscissa axis at a point having the value of abscissa d1-d, where d is the duration of mechanical opening of the shutter of the injector. The slope Qs is therefore deduced from d and from Me by the relation (2) given above. When ordering the injector, several parameters determine the duration of mechanical opening of the injector.
• This duration d of mechanical opening of the injector is the time during which the shutter of the injector (for example the needle of the injector) is in the maximum opening position (the needle is in mechanical stop) or almost maximum.
• FIG. 4 illustrates the method of calculating this value d.
• FIG. 4 comprises a first curve C2 representing the variation over time of the electrical control signal of the injector and a second curve C3 representing the variation over time of the position of the needle of the injector.
• the duration d of mechanical opening of the injector depends on the following parameters: the duration d1 of electrical control of the injector, that is to say, when the electrical actuating member of the injector is a coil , the time interval elapsing between the instant t1 of energization of the injector coil and the instant t2 of energization of the injector coil; the time interval d2 necessary for the mechanical opening of the injector, that is to say, when the mechanical shutter of the injector is a needle and the electric actuator of the injector is a coil, the time interval between the instant t1 of energization of the injector coil and the instant t3 when the needle is actually open; this time interval depends on the speed of opening of the shutter of the injector and of a dead time existing between instant t1 and the effective start of the mechanical opening of the shutter; the time interval d3 necessary for the mechanical closure of the injector, that is to say, when the mechanical shutter of the injector is a needle and the electrical actuator of the inject
• d1 is obtained by the calculation means 12 from the control means 10 which generated it
• d2 and d3 are predetermined fixed values or variables depending on certain parameters (the battery voltage, for example, measurable by the computer), and are read or reconstructed from values stored in a table or a memory associated with the calculation means 12.
• the computer 1 further comprises a sensor 11 for measuring the pressure of the fuel in the fuel supply circuit 7 and means, for example forming part of the computer 1, for comparing the measurement of the pressure carried out by the sensor 11 with the value of the reconstituted pressure determined by the calculation means 12.
• the result of the comparison is used by diagnostic means 3 to establish a diagnosis on the operating state (correct operation or failure) of said pressure sensor 11.
• the indirect injection device shown in FIG. 2 has neither a pressure sensor, nor a means of diagnosing the pressure sensor.
• the computer 1 further comprises means 13 for triggering a fallback operating mode, when the calculated value of fuel pressure is greater, respectively less, than a value of predetermined maximum threshold, respectively minimum.
• the device according to the invention comprises regulating means 14 for regulating the pressure from said reconstituted pressure value.
• the regulation will be carried out in this embodiment, in open loop.
• the regulation means will in this case preferably be produced in the form of an electric regulator.
• the reconstituted pressure value will be determined only in predetermined engine operating zones so as to guarantee the reliability of the pressure information thus obtained. These zones are quasi-stabilized operating zones for which the variations in engine speed and intake air pressure are slow. This embodiment can be applied for example in the absence of the pressure sensor 11 or in the event of a malfunction thereof.
• the diagnostic means 3 of the sensor, the means 13 for triggering a fallback operating mode can cooperate effectively with the regulation means 14.
• the device according to the invention comprises means for detection (for example by calculation by the calculation means 12) of the rapid drifts of the reconstituted fuel pressure value and / or of the fuel pressure measurement value coming from the sensor 11 and comprises means 15 for establishing a diagnosis on the state of the fuel supply circuit 7 from said drifts. We can thus detect a problem of connection or blocked piping.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (4)

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Family Cites Families (9)

• 2004
  • 2004-02-18 FR FR0401595A patent/FR2866390B1/fr not_active Expired - Fee Related
• 2005
  • 2005-02-01 US US10/589,854 patent/US20070157904A1/en not_active Abandoned
  • 2005-02-01 EP EP05715234A patent/EP1730393A1/de not_active Withdrawn
  • 2005-02-01 WO PCT/EP2005/000964 patent/WO2005090767A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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