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
  • F02D41/30—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
  • F02D41/3845—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
  • F02D41/3854—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped with elements in the low pressure part, e.g. low pressure pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/20—Varying fuel delivery in quantity or timing
  • F02M59/34—Varying fuel delivery in quantity or timing by throttling of passages to pumping elements or of overflow passages, e.g. throttling by means of a pressure-controlled sliding valve having liquid stop or abutment
• • 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
• • 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
  • F02D2200/0614—Actual fuel mass or fuel injection amount
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/02—Fuel evaporation in fuel rails, e.g. in common rails
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/31—Control of the fuel pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/20—Varying fuel delivery in quantity or timing
  • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
  • F02M59/366—Valves being actuated electrically

Definitions

• the present invention relates to a method of controlling a fuel injection system of an internal combustion engine, the fuel injection system comprising a manifold and an engine speed driven high pressure pump and associated with the high pressure pump is a fuel metering unit having an electromagnetically operable fuel control valve, the fuel metering unit controlling the amount of fuel delivered.
• Such a fuel injection system is known from DE 198 53 103 Al. It comprises a high-pressure pump, the delivery rate of which can be adjusted by metering the amount of fuel reaching a delivery chamber of the high-pressure pump.
• a Kraftstoffzumessaku is provided upstream of the pumping chamber, which comprises an electromagnetically actuated control valve.
• an opening cross-section through which the fuel must pass on the way to the delivery chamber, is more or less released.
• the delivery rate of the high pressure pump is proportional to the opening cross section.
• the opening cross section may have a slot-shaped, circular or triangular geometry.
• the object of the present invention is therefore to provide a method and a device which enable improved metering of an amount of fuel which is supplied to a high-pressure pump provided in a fuel injection system.
• the fuel injection system includes a manifold and a high pressure pump.
• the high pressure pump is associated with a fuel metering unit.
• the fuel metering unit controls the amount of fuel delivered.
• An amount of fuel required to operate the internal combustion engine is determined in response to a correction factor based on a fuel pressure at the inlet of the high pressure pump and / or a vapor pressure of the fuel to be delivered.
• the high pressure pump is preferably driven engine speed dependent, for example, by a drive connected to the crankshaft.
• the metering unit preferably comprises an electromagnetically operable control valve for supplying fuel.
• the invention thus makes it possible to influence the delivered fuel quantity as a function of the fuel pressure at the inlet of the high-pressure pump and / or the vapor pressure of the fuel to be supplied in order to ensure an improved metering of the quantity of fuel supplied to the high-pressure pump.
• the control quality of the pressure control in the distributor tube can be improved according to the invention and geometric and / or electrical tolerances of the high-pressure pump or the fuel metering unit can be compensated
• the correction factor according to the invention is defined as the pressure difference between the fuel pressure at the inlet of the high-pressure pump and the vapor pressure of the fuel.
• the high-pressure pump preferably has a delivery chamber with a check valve arranged on the input side, an opening pressure of the check valve being determined for determining the correction factor. This is subtracted from the pressure difference to determine a pressure correction value.
• the pressure difference effective at the control valve which affects the amount of fuel delivered, is determined and used as a correction factor for correcting the amount of fuel supplied to the high-pressure pump.
• a more precise precontrol of the high-pressure pump can be achieved by the fuel metering unit, whereby the influence of the fuel type and the corresponding admission pressure is reduced and an improved diagnosis is made possible.
• a desired fuel volume to be supplied to the high-pressure pump is preferably determined, the required fuel quantity being determined based on the desired fuel quantity.
• Fuel volume and the correction factor is determined.
• the correction factor can be determined on the basis of a characteristic curve which defines suitable volume correction values for possible pressure correction values.
• an opening cross-section of the control valve is determined as a function of the correction factor, which is set to supply the required amount of fuel.
• a control signal for the control valve is determined.
• the drive signal is determined on the basis of a characteristic curve that defines suitable drive signals as a function of possible opening cross sections and actual engine speeds.
• control valve is controlled in response to the correction factor, so that the fuel pressure at the inlet of the high-pressure pump and / or the vapor pressure of the fuel to be supplied are taken into account in the control of the control valve and an improved metering of the amount of fuel delivered is guaranteed.
• the use of a characteristic allows a quick and easy determination of the drive signal.
• the vapor pressure is determined in one embodiment of the invention from the actual temperature using at least one reference vapor pressure curve.
• the pre-pressure to determine the vapor pressure is reduced from an initial value until the delivery of the high pressure pump is zero and the vapor pressure of the difference of the pre-pressure and an opening pressure of a check valve of the high-pressure pump is determined.
• an internal combustion engine having a fuel injection system comprising a manifold and a high pressure pump.
• the high pressure pump is associated with a fuel metering unit.
• the fuel metering unit controls the amount of fuel delivered.
• An amount of fuel required to operate the internal combustion engine is determinable as a function of a correction factor based on a fuel pressure at the inlet of the high-pressure pump and / or a vapor pressure of the fuel to be supplied.
• Fig. 1 is a schematic representation of a fuel injection system of a
• FIG. 2 is a partial section through a portion of the fuel metering unit of FIG. 1 shown broken away;
• FIG. 3 shows a schematic representation of a method for determining an opening cross section for a control valve of the fuel metering unit of FIG. 1;
• FIG. 4 is a schematic representation of a method for determining a drive signal for a control valve of the fuel metering unit of FIG.
• Fig. 1 shows a schematic representation of a fuel injection system 10 a
• Internal combustion engine This comprises a fuel tank 12 from which a feed pump 14 delivers fuel to an inlet 15 of a fuel metering unit 16. Its outlet 18 leads to a high-pressure fuel pump 20.
• the low-pressure line extending from the fuel tank 12 to the high-pressure pump 20 bears the reference numeral 22 overall.
• the high-pressure pump 20 preferably has a delivery chamber with a check valve arranged on the input side, compresses the fuel to a very high pressure and delivers it to a fuel collecting line 24, in which the fuel is stored under very high pressure and which also acts as a "distributor tube”. or “RaN” is called.
• the internal combustion engine serves, for example, for driving a motor vehicle.
• the pressure in the fuel rail 24 is detected by a pressure sensor 30. Its signals are transmitted by the pressure sensor 30 to a control and regulating device 32, whose output is connected, inter alia, to the fuel metering unit 16.
• a control and regulating device 32 whose output is connected, inter alia, to the fuel metering unit 16.
• the fuel metering unit 16 is in still darwinder way the Flow rate of the high-pressure pump 20 is set. In this way, the actual pressure in the fuel rail 24, which is detected by the pressure sensor 30, a nominal pressure to be tracked.
• the fuel metering unit 16 is formed as a suction throttle. It comprises a housing 34, in which a valve piston 36 is received axially displaceable. The valve piston 36 protrudes into a valve chamber 38, in which a valve slide 40 is received axially displaceable. The valve spool 40 is pressed by a compression spring 42 against the valve piston 36.
• the inlet 15 of the fuel metering unit 16 is formed at the axial end of the valve chamber 38, whereas the
• Outlet 18 is formed in a radial wall 44 of the valve chamber 38 in the form of a control port 46.
• the position of the valve piston 36 is adjusted by an electromagnetic actuator 48.
• the valve spring 42 pushes the valve spool 40 and the valve piston 36 in Fig. 2 completely down. This condition is shown in the left half of FIG.
• the electromagnetic actuator 48 is energized, the valve piston 36 pushes the valve spool 40 against the force of the valve spring 42 in Fig. 2 upwards, so that the control orifice 46 in the radial wall 44 partially or in the end position, completely ü - covered.
• This state is shown in the right half of FIG. 2. If the control opening 46 is completely free, a maximum amount of fuel passes from the pre-feed pump 14 to the high-pressure pump 20 and from there further into the rail 24. This operating state is referred to as full delivery. On the other hand, if the control opening 46 is partially covered by the valve spool 40, a smaller quantity of fuel is admitted
• FIG. 3 shows a schematic representation of a method for determining an opening cross-section rozme_w for the valve piston 36, the electromagnetic electromagnetically operable control valve of the fuel metering unit 16 of FIGS. 1 and 2.
• the method is implemented as a computer program and executed by the control and regulating device 32.
• a fuel mass mkreff_w injected from the high pressure pump 20 into the manifold 24 is calculated. This is converted in a step 153 as a function of a temperature-dependent fuel density KLROHKRTF in the high-pressure pump 20 to be supplied nominal fuel volume vmkreff_w.
• the temperature-dependent fuel density KLROHKRTF can be determined according to the invention in a step 152 on the basis of a suitable characteristic curve based on a measured fuel temperature tfuelsq.
• an amount of fuel required for operating the internal combustion engine is determined from the nominal fuel volume vmkreff_w to be supplied and a correction factor KLFOZMEDP. This required amount of fuel must be supplied to the high-pressure pump 20 and from this to the distributor pipe 24 in order there to ensure a fuel pressure and throughput required for the respective operating state of the internal combustion engine.
• the opening cross section rozme_w of the control valve is determined in step 154. This is set to supply the required amount of fuel to the high-pressure pump 20. As described below with reference to FIG. 4, a suitable control signal for the control valve is determined based on the determined opening cross section rozme_w.
• the correction factor KLFOZM EDP can be determined in a step 148 on the basis of a characteristic field. This describes volume correction values depending on possible pressure correction values, which are suitable as a correction factor KLFOZM EDP for determining the required amount of fuel.
• the method according to the invention is preferably executed in the form of a loop by the control and regulating device 32. Accordingly, the correction factor KLFOZMEDP is determined in step 148 for an actual pressure correction value dpzme_w, respectively. This is determined in step 146 by subtracting the vapor pressure Pdampf of the fuel to be supplied and the opening pressure peiv of the check valve from the fuel pressure pekp at the inlet of the high-pressure pump 20. In this case, the vapor pressure Pdampf of the zuzu meetings.
• Fuel and the opening pressure peiv the check valve be summed in a step 144 beforehand.
• a pressure difference between the fuel pressure pekp at the inlet of the high-pressure pump 20 and the vapor pressure Pdampf of the fuel to be supplied can also first be determined.
• the opening pressure peiv of the check valve is subtracted from the determined pressure difference to determine the pressure correction value.
• the actual pressure correction value dpzme_w can also be determined on the basis of an empirically determined relationship, such as e.g. a characteristic field.
• a suitable characteristic field can be determined as a function of the vapor pressure Pdampf and fuel pressure pekp, e.g. for low-pressure systems with variable fuel pressure, or only as a function of steam pressure Pdampf, z. B. for low pressure systems with constant fuel pressure pekp.
• the vapor pressure Pdampf can be determined in various ways. This depends mainly on the temperature and only to a limited extent on the fuel used. Accordingly, the steam pressure Pdampf in the simplest
• the steam pressure Pdampf may be determined using the adapted start-up or warm-up factor, or using the adapted factor of Cl-transition compensation. These correlate directly with the vapor pressure Pdampf of the fuel used, since they represent a measure of the evaporation tendency of the fuel.
• the opening pressure peiv can be regarded as constant with good approximation.
• the steam pressure Pdampf can be determined by the fact that in the context of tank ventilation, a value is determined which serves as a measure of the loading of the associated active carbon filter, with a high value indicating a very volatile fuel. From this value, taking into account a respective actual temperature, the vapor pressure Pdampf can be determined.
• the admission pressure pekp can be measured with a suitable sensor or modeled based on activation parameters of the electric fuel pump 14.
• a suitable sensor or modeled based on activation parameters of the electric fuel pump 14.
• Pressure regulator whose set opening pressure, taking into account the pressure drop across the fuel line 22 are used.
• this method is also implemented as a computer program and executed by the control and regulation device 32.
• step 160 based on the gem.
• Fig. 3 determined opening cross-section rozme_w and a respective actual engine speed nmot_w a suitable drive signal tavstzme_w determined for the control valve. This is preferably determined on the basis of a characteristic field which has different characteristic curves for different possible actual engine speeds nmot_v, wherein each characteristic curve defines suitable drive signals tavstzme_w as a function of possible opening cross-sections rozme_w.

Landscapes

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

Applications Claiming Priority (2)

Publications (2)

Family

ID=39929681

Family Applications (1)

Country Status (6)

Families Citing this family (10)

Family Cites Families (25)

• 2007
  • 2007-10-22 DE DE102007050297A patent/DE102007050297A1/de not_active Withdrawn
• 2008
  • 2008-09-11 US US12/739,150 patent/US8793059B2/en not_active Expired - Fee Related
  • 2008-09-11 AT AT08804049T patent/ATE498769T1/de active
  • 2008-09-11 JP JP2010530373A patent/JP5518723B2/ja not_active Expired - Fee Related
  • 2008-09-11 DE DE502008002646T patent/DE502008002646D1/de active Active
  • 2008-09-11 EP EP08804049A patent/EP2205846B1/fr not_active Not-in-force
  • 2008-09-11 WO PCT/EP2008/062084 patent/WO2009053158A1/fr active Application Filing

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events