Classifications

• • 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
  • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
  • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
• • 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
  • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
  • F02M63/0012—Valves
  • F02M63/0014—Valves characterised by the valve actuating means
  • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
  • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
• • 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
  • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
  • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
  • F02M47/027—Electrically actuated valves draining the chamber to release the closing 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
  • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
  • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
  • F02M63/0205—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively for cutting-out pumps or injectors in case of abnormal operation of the engine or the injection apparatus, e.g. over-speed, break-down of fuel pumps or injectors ; for cutting-out pumps for stopping the engine
• • 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
  • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
  • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
  • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
• • 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
  • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
  • F02M2547/003—Valve inserts containing control chamber and valve piston

Definitions

• the invention relates to a fuel injection system for an internal combustion engine having at least one cylinder.
• a fuel injection system for multi-cylinder internal combustion engines is known from DE 44 14 242 A1, in which each cylinder is assigned an injection unit which is supplied with fuel by a high-pressure fuel supply which is under a relatively high pressure.
• a high-pressure fuel supply has a flow restriction valve in front of the injection unit, which closes when the fuel flowing out of the flow restriction valve reaches a maximum fuel quantity. In this way, damage to the internal combustion engine due to leakage in the injection unit is to be avoided.
• DE 197 09 794 A1 describes an injection unit in which an injection valve is axially adjustable, which has a valve needle and a piston connected to the drive, the valve needle is arranged between an injection nozzle opening into a combustion chamber of the cylinder and a nozzle feed line communicating with the high-pressure fuel supply, and the piston at one end facing away from the valve needle with a closing surface in a closing pressure chamber and at one of the
• Valve needle-facing end with an opening area protrudes into an opening pressure chamber. While the closing pressure chamber communicates with the high pressure fuel supply via a throttle, the opening pressure chamber is connected without restriction to the high pressure fuel supply.
• a control valve is arranged between the closing pressure chamber and a relief chamber in which there is a relatively low pressure. The closing area is chosen larger than the opening area.
• the closing pressure chamber and the relief chamber are communicatively connected to one another so that a pressure drop takes place in the closing pressure chamber. Since the pressure in the opening pressure chamber remains the same, a resulting force acts on the piston, which drives the injection valve into its open position. To open the injection valve, the valve needle is pulled out of a valve seat formed in the injection nozzle, so that the fuel can inject into the combustion chamber at high pressure.
• the maximum fuel quantity defined in the flow limiting valve must be selected so that it contains the following fuel partial quantities:
• a further partial fuel quantity results from the control quantity which is required in order to be able to carry out the pressure relief of the closing pressure space at which fuel flows into the relief space in order to open the injection valve.
• the leakage quantity which is just tolerable for the respective injection unit and which is composed in particular of leaks in the injection valve and in the control valve must be taken into account as a further fuel subset.
• the fuel injection system according to the invention with the features of claim 1 has the advantage over that the fuel can be narrowed to a minimum, so that the flow limiting valve responds earlier, thereby improving the protection of the internal combustion engine from damage.
• the maximum fuel quantity can be reduced in the fuel injection system according to the invention, since the flow limiting valve is arranged in the nozzle feed line and thus works independently of leaks in the control valve. Accordingly, the maximum fuel quantity in the fuel injection system according to the invention can be reduced by the relatively large control quantity and by the leakage quantity tolerable for the control valve. Accordingly, the new one
• Fuel injection systems are shown in the drawings and are explained in more detail below.
• FIG. 1 is a sectional view of an injection unit of the fuel injection system according to the invention
• Fig. 2 is a sectional view through a detail marked II in Fig. 1 in another
• FIG. 3 shows a sectional view of the detail from FIG. 2 corresponding to the section lines III in FIG. 2.
• the fuel injection system according to the invention is usually used in an internal combustion engine with a plurality of cylinders, each of these cylinders being assigned an injection unit.
• such an injection unit 1 is supplied with fuel via a high-pressure fuel supply 2, which is at a relatively high pressure, namely the injection pressure.
• the injection unit 1 contains a rod-shaped injection valve 3, which is mounted in the injection unit 1 in an axially adjustable manner.
• the injection valve 3 consists of a cylindrical piston 4 which is drive-connected at one axial end to a valve needle 5.
• This valve needle 5 has at its axially free end a conical needle tip 6, which cooperates with a needle valve seat 8 formed in an injection nozzle 7.
• the injection nozzle 7 protrudes into a combustion chamber 9 of the cylinder assigned to the injection unit 1, which is only shown symbolically.
• a radial sleeve-shaped annular gap 10 is formed, which opens into an annular opening pressure chamber 11 when the valve needle 5 passes into the piston 4.
• the axial end of the piston 4 facing the valve needle 5 projects into this opening pressure chamber 11, an opening surface 12 being formed due to the diameter difference between the piston 4 and the valve needle 5, which is exposed to the pressure prevailing in the opening pressure chamber 11.
• the opening pressure chamber 11 communicates via a
• this nozzle inlet line 13 there is a flow limiting valve 14 - described in more detail below.
• the high pressure or the injection pressure of the fuel prevails in the opening pressure chamber 11 via the communicating connection of the opening pressure chamber 11 with the high-pressure fuel supply 2.
• Piston 4 has a closing pressure chamber 15 formed in the injection unit 1, into which the piston 4 projects with its axial end face, which forms a closing surface 16 exposed to the pressure prevailing in the closing pressure chamber 15.
• the closing pressure space 15 communicates via a throttle 17 with an annular space 18 formed in the injection unit 1 is in turn connected to the high-pressure fuel supply 2 via a bore 19 and a line 20.
• the same high pressure or injection pressure of the fuel can be set in the closing pressure chamber 15 as in the opening pressure chamber 11.
• the closing surface 16 is larger than the opening surface 12, this results in a downward-acting, driving the needle tip 6 in the needle valve seat 8 Force.
• the closing pressure chamber 15 communicates via a
• Relief bore 21 with a relief chamber 22, in which there is a relatively low pressure, for example ambient pressure.
• a valve seat 23 is formed in the relief chamber 22, with which a valve body 24 of a control valve 25, which is axially adjustably mounted in the injection unit 1, cooperates to open and close the relief bore 21.
• the valve body 24 is prestressed into its closed position, that is to say into the valve seat 23, by means of a helical compression spring 26.
• the valve body 24 is drive-connected to a control piston 27, which has an end facing the valve body 24
• Has pressure shoulder 28 which protrudes into a pressure chamber 29 and is thus exposed to the pressure prevailing therein.
• a pressure surface 30 of an electrically actuable piezo actuator 31 also projects into this pressure chamber 29.
• the injection unit 1 works as follows:
• the piezo actuator 31 In a rest position of the injection unit 1, the piezo actuator 31 is deactivated, so that the helical compression spring 26 biases the valve body 24 into its closed position. As a result, the relief chamber 22 is separated from the closing pressure chamber 15, so that the injection pressure can build up in the closing pressure chamber 15 via the throttle 17. If the injection pressure prevails in the closing pressure chamber 15, the closing force developing on the closing surface 16 is greater than that on the Forming the opening area 12 in the opening pressure space 11
• the piezo actuator 31 When an injection is to take place, the piezo actuator 31 is electrically activated, which expands, so that its pressure surface 30 penetrates into the pressure chamber 29 and displaces a transmission liquid introduced therein. In a corresponding manner, a force acts on the pressure shoulder 28 of the control piston 27, which adjusts the control piston 27 and thus the control valve 25 in the opening direction. As soon as the valve body 24 releases the connection between the relief chamber 22 and the closing pressure chamber 15, the pressure in the closing pressure chamber 15 drops, since less fuel can flow in via the throttle 17 than flows out via the relief bore 21. As a result, there is a pressure drop in the closing pressure chamber 15, while the pressure in the opening pressure chamber 11 remains constant. As a result, the opening force acting on the piston 4 becomes greater than the compressive force and the needle tip 6 lifts off the needle valve seat 8. The fuel supplied via the annular gap 10 to the injection nozzle 7 can then be injected into the combustion chamber 9 with the injection pressure.
• the piezo actuator 31 is deactivated again, so that the control valve 25 closes again due to the spring 26.
• the injection pressure can then build up again relatively quickly in the closing pressure chamber 15, so that the closing force again becomes greater than the opening force and the injection valve 3 closes.
• the amount of fuel that can enter the combustion chamber 9 through the injection nozzle 7 is by an in
• Flow limiting valve 14 limits the maximum amount of fuel defined. When this maximum fuel quantity is specified, tolerable leaks in the control valve 25 and the control quantity required to control the injection valve 3 can occur be ignored.
• the control amount is the amount of fuel that escapes from the closing pressure chamber 15 into the relief chamber 22 when the control valve 25 is open, fuel continuously flowing into the closing pressure chamber via the throttle 17.
• connection receptacle 32 is formed in the injection unit 1, into which a connection piece 33 is inserted in order to connect the injection unit 1 to the high-pressure fuel supply 2.
• a thread 34 is provided, which enables a high-strength connection between the receptacle 32 and the piece 33.
• the connecting piece 33 contains a coaxial first
• Fuel channel 35 which opens into a sealing cone 36 at the axial end of the connecting piece 33.
• the sealing cone 36 penetrates into a complementary sealing seat 37, which is formed in the receptacle 32.
• a first fuel line 38 which communicates with the nozzle 7 (see FIG. 1), opens into this sealing seat 32.
• the first fuel line 38 and the first fuel channel 35 thus form the nozzle feed line 13 from FIG. 1.
• the flow limiting valve 14 is arranged in the connecting piece 33.
• This flow limiting valve 14 is constructed in a conventional manner and contains an axially adjustable piston 39, which has an inlet opening 40 and an outlet opening 42 connected to it via a throttle point 41.
• the piston 39 is biased in the upstream direction via a helical compression spring 43.
• a delivery chamber 45 is formed between the piston 39 and a stop plate 44 arranged downstream, the volume of which is essentially that
• the funding room 45 communicates via an outlet opening 46 to the downstream part of the first fuel channel 35.
• the delivery chamber 45 is emptied to such an extent that an end plate 47 of the piston 39 comes into contact with the stop plate 44 and the outlet opening 46 closes tightly. A more extensive fuel outlet from the injection nozzle 7 can then no longer take place.
• the piston 39 of the flow limiting valve 14 can only move upstream again into its starting position when there is a pressure in the outlet opening 46 which is sufficient to lift the end plate 47 from the stop plate 44. This is regularly the case when the injection valve 3 closes properly.
• a second fuel channel 48 is also formed, which opens laterally of the sealing cone 36 into an annular space 49, which is formed in the receptacle 32 between the latter and the nozzle 33.
• This annular space 39 is sealed to the outside via an annular seal 50.
• a second fuel line 51 is formed in the injection unit 1 and communicates at one end with the annular space 18 and at the other end with the annular space 49. In the embodiment in FIG. 1, this second fuel line 51 corresponds to the bore 19 and the second fuel channel 48 corresponds to the line 20.
• the pressure prevailing in the high-pressure fuel supply 2 propagates through the second fuel channel 48, the annular space 49, the second fuel line 51, the annular space 18 and the throttle 17 into the closing pressure space 15.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Fuel-Injection Apparatus (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7892962

Family Applications (1)

Country Status (6)

Families Citing this family (14)

Family Cites Families (12)

• 1998
  • 1998-12-28 DE DE19860476A patent/DE19860476A1/de not_active Withdrawn
• 1999
  • 1999-11-18 JP JP2000591324A patent/JP2002533614A/ja active Pending
  • 1999-11-18 WO PCT/DE1999/003661 patent/WO2000039452A2/de not_active Application Discontinuation
  • 1999-11-18 KR KR1020007009451A patent/KR20010041338A/ko not_active Application Discontinuation
  • 1999-11-18 US US09/623,355 patent/US6374802B1/en not_active Expired - Fee Related
  • 1999-11-18 EP EP99960917A patent/EP1097303A2/de not_active Withdrawn

Non-Patent Citations (1)

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