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
  • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
  • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
  • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
  • F02M61/166—Selection of particular materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N35/00—Magnetostrictive devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N35/00—Magnetostrictive devices
  • H10N35/80—Constructional details
  • H10N35/85—Magnetostrictive active materials

Definitions

• the present invention relates to control means for precision control of valves of the kind having a through opening which is steeplessly adjustable by means of a valve member which is movable within the valve.
• valves of the kind mentioned initially in order to control the flow of a gaseous or fluid medium to a recipient, e.g. a prime mover operated by the medium or in order to pro- vide dosage of the medium in accordance with a pre ⁇ determined program .
• a recipient e.g. a prime mover operated by the medium or in order to pro- vide dosage of the medium in accordance with a pre ⁇ determined program .
• pur ⁇ poses many different types of valves are available on the market, ranging from simple magnet valves to servo valves of a rather complicated construction. In such cases where the intended control requires fast, accurate and flexible adjustment of the valves, the more simple types of electrically controllable valves, e.g. magnet valves etc., can not be used due to unsufficient control characteristics.
• a frequently used type of servo valves may thus include an electrically controlled pilot valve, controlling a pilot flow, which in turn acts on the valve member of a con ⁇ nected control valve controlling a second control flow, which in turn acts upon the valve member of the main valve in dependence of electrical control signals supplied to the pilot valve.
• the influence of inertial forces, flow resistance and frictional forces acting upon the elements of the servo valve sets up limits for the control characteristics that may be obtained, which often makes it impossible to achieve such control characteristics which otherwise would be desirable.
• Still another object in con ⁇ nection with fuel injection in diesel engines which, for the reasons previously mentioned, up till now has proved impossible to obtain is the capability to control the injection sequence in dependence of the instantaneous load on the engine for optimizing the energy efficiency at full load as well as at partial load.
• the object of the present invention is to provide control means of the kind mentioned initially which renders possible a very rapid, exact and flexible control of the through opening of valves and steepless and extremely finely graded control also of very small movements and rapid sequences, at the same time providing an uncomplicated construction due to the . re ⁇ duction to a minimum of the number of control elements.
• Another object is to provide control means of the kind
• Fig 1 is a longitudinal section through a valve in accordance with the invention adapted to control the injection of fuel in a diesel engine
• Fig 2 illustrates schematiclly a system for control of the fuel injection in a 4-cylinder diesel engine in which the control means according to the in ⁇ vention includes valves of the kind shown in Fig 1.
• the injection valve shown in Fig 1 includes a cylindrical casing 1, one end of which having a protruding, externally threaded part 2.
• the externally threaded part 2 has a planar end wall 3 in sealing contact with a corresponding planar end wall 4 of an in ⁇ jection nozzle 5.
• the injection nozzle 5 is by means of an internally threaded gland nut 6 clamped on the axially protruding part 2 of the casing 1.
• the injection nozzle 5 is in a manner known per se provided with a nozzle opening 7, surrounded by a seat 8 and an annular chamber 9.
• the injection nozzle 5 also comprises a jet needle 10 which is displacable axially within a cylindrical bore 11 in the nozzle in which the jet needle is steeplessly adjustable between a closed position in sealing abutment against the seat 8 surrounding the nozzle opening 7, and a fully open position for through flow of fuel through the nozzle opening 7.
• the annular chamber 9 is by means of a passage 12 connected to an annular groove 13 in the upper planar surface 3 in the injection nozzle 5.
• the nozzle 5 is supplied with fuel through a passage 14 in the cylindrical wall of casing 1, said passage opening into the groove 13 in the upper surface 3 of nozzle 5.
• the passage 14 extends in the longitudinal direction of the casing 1 and opens into a connection nipple 15 at the opposite end of the casing 1, said nipple by means of a supply line not shown in the figure being connected to a source of fuel, not shown, for supplying the nozzle with diesel fuel under pressure.
• the injection needle 10 which is formed as a displaceable valve member is rigidly connected with one end of a control element 16 in the form of a rod of giant magnetostrictive material.
• the opposite end of the control element is fixed to a rigid supporting structure, which in the fuel injection valve shown in Fig 1 is formed by the upper end portion of casing 1.
• the upper end of the rod-like control element 16 is thus rigidly attached to the end wall 17 of the cylindrical casing 1, e.g. by being screwed into a threaded bore in said end wall 17.
• the end wall 17 in turn is externally threaded and screwed into the upper end portion of casing 1 which is provided with a cor- responding internal thread.
• the mechanical connection between the lower end of the rod-like control element 16 and the jet needle includes a cylindrical flange 18 ex ⁇ tending transversally and supporting one end of a com ⁇ pression spring 19 which extends coaxially with respect to the control element 16.
• the opposite end of said com ⁇ pression spring 19 is supported in abutment against a partition wall 20 extending transversally within the casing.1.
• said partition wall 20 being provided with an opening through which the rod-like control element 16 extends, the dimensions of said opening being chosen to provide a certain claerance between the rod-like control element and the edges of said opening.
• the compression spring 19 gives rise to a tensile stress in the rod-like control element 16, and the spring characteristics should be chosen so that a substantially constant pre- stress is maintained in the control element 16 within its intended range of movement. The reasons of this pre-stressing will be discussed in more detail later.
• the rod-like control element 16 is further surrounded by a solenoid 21 disposed within the casing 1 in the space which is limited by the lower partition wall- 20, the upper end wall 17 and the outer wall of the casing 1. A certain clearance is provided between the inside of the solenoid 21 and the periferal surface of the rod-like control element 16.
• the electric con ⁇ nections 22 of the solenoid 21 extend transversally through the casing 1 at the upper part thereof and are connected to a source of electric current, not shown in Fig 1, supplying the solenoid 21 with electric current in dependence of digital or analogue electric signals from a control unit, not shown in Fig 1, which controls the supply of current to the solenoid in accordance with the pre-deter ined program.
• the source for supplying electric current as well as the control units included in the device are, however, indicated in the schematically illustrated system for control of the fuel injection in a 4-cylinder diesel engine swhown i Fig 2.
• control element 16 is made of a so called giant agnetostrictive material, e.g. an alloy between rare earths metals such a samarium (S ) , -terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er) , tulium (T ) and magnetic transition metals such as iron (Fe), cobalt (Co) and nickel (Ni).
• This group of alloys presents the largest magnetostriction known so far, e.g. possessing the property to undergo a change in dimension under the influence of a magnetic field, said change in dimension being proportional to the intensity of the magnetic field.
• the magnitude of the magnetostriction in these materials is of a quite different range than is the case in ordinary magnetostrictive materials, e.g. iron-nickel.
• iron-nickel undergoes a change in length of 20 - 30 iim/m
• an alloy of e.g. terbium-dysprosium-iron undergoes a change in length of 1700 um/m.
• the change in length to which said giant magnetostrictive materials are subject under the influence of the magnetic field may be positive or negative, e.g. may for certain of said compositions result in an increase in length and for other of said compositions result in a decrease in length.
• Both types of giant magnetostrictive materials may be used according to the present invention.
• the magnitude of the magnetostriction under the influence of a certain magnetic field varies, and it is of course preferred to use in the embodiments according to the present in ⁇ vention giant magnetostrictive materials having the largest magnetostrictive properties.
• alloys the first mentioned gives rise to an increase in length under the influence of an increasing magnetic field whereas the last mentioned alloy undergoes a decrease in length under the influence of said magnetic field.
• control element In order to obtain satisfactory results in use the control element should be pre-stressed in a direction opposite the actual direction of movement under the in- fluence of the magnetic field. The reason to this is that a pre-stressing counteracts mechanical hysteres in the magnetostrictive material. The amount of pre- stressing needed is different for different magnetostrictive materials.For a giant magnetostrictive material comprising e.g. an alloy between terbium, dysprosium and iron in the relation Tb n consider 7 Dy_ -.Fe, g5 , the pre-stress together with the load should amount to 12 MP .
• a giant magnetostrictive material comprising e.g. an alloy between terbium, dysprosium and iron in the relation Tb n consider 7 Dy_ -.Fe, g5
• the pre-stress together with the load should amount to 12 MP .
• Magnetostrictive materials of the kind which undergoes an increase in length under the influence of the magnetic field should be pre-stressed by a compressive stress whereas magnetostrictive materials which decrease in length under the influence of the magnetic field should be pre-stressed by a tensile stress.
• the prestress can be provided by means of a mechanical spring having suitable characteristics, as illustrated in Fig 1 in which the spring 19 is adapted to give rise to a tensile stress in the control element 16, as described previously.
• the magnetostrictive material As well as the magnet coil generates heat.
• the heat generation results in a linear termal expansion of the material.
• the change in dimension due to said heat generation must be compensated for. This may be effected by chosing materials having equal or almost equal coefficient of termal heat expansion or by taking measures to keep the temperature constant.
• the termal expansion can also be compensated for by means of an active compensation
• control system includes a feed-back system according to which the movement of the control element is measured, e.g. the instantaneous position of the control element is detected, and the electrical signals thus generated are fed back to the control circuit, it is possible to compensate for the linear thermal expansion.
• the fuel injection valve shown in Fig 1 operates in the following manner.
• a magnetic field is generated in the solenoid the axial direction bf which being parallel with the intended, direction of movement of the control element 16.
• the magnetic field causes a change in dimension of the control element consisting of giant magnetostrictive material. Since the control element in the example illustrated in Fig 1 is presupposed to be made of a giant magnetostrictive material of the kind which undergoes a decrease in dimension under the influence of a magnetic field, the length of the control element 16 decreases.
• OMPI steeplessly variable during the injection sequence, thus steeplessly varying the amount of fuel that is injected per unit of time.
• the change of the length of the control element 16 under the influence of the magnetic field takes place under minimal influence of inertial forces etc., which renders possible a very fast, steepless and exact adjustment of the jet needle and consequently an exact adjustment of the amount of fuel injected per unit of time.
• the present invention renders possible such an accurate control of the amount of fuel injected per unit of time during the injection sequence which previously could not be obtained.
• Fig 2 illustrates, very schematically, an embodiment according to the invention for control of the fuel injection in a 4-cylinder diesel engine, schematically represented on the drawing and referred to under reference numeral 23 and its crank shaft being re- ferred to under reference numeral 24.
• a fuel injection valve 25, 26, 27 and 28 of the kind described with reference to Fig 1.
• the fuel injection valves 25 - 28 are represented only by the control element 16 and the solenoid 21.
• Each solenoid 21 is supplied with currect from a separate current generator 29, 30, 31 and 32.
• Each of those current generating sources is by means of an individual electric control line 33, 34, 35, 36 connected to a separate output on the output side of a control device 37, consisting of a computer.
• An injection algoritm 40 is registed in the computer, said algoritm exactly de ⁇ fining the injection process in dependance of a number of selected parameters, e.g. the cetane rating, type of load (full load or partial load) etc., said parameters being- set in the form of panel values 41 on the input side 39 of the computer.
• the positions of the piston within the cylinders are detected from crank shaft 24 by means of a angle transmitter 42, emitting control signals representing the crank shaft angle, angle of velocity and angle- of acceleration, said signals being fed through a line 43 to an input on the input side 39 of the computer.
• a temperature transmitter By means of a temperature transmitter the exhaust gas temperature is senced and the signals from the transmitter are fed through line 44 to an input on the input side of the computer.
• the fuel injection valves 25 - 28 are provided with e.g. optical transmitters 45 in ⁇ dicating the instantaneous position of the jet needle of each valve and emitting electrical signals in dependence of the respective position to inputs 46 - 49 on the in ⁇ put side of the computer.
• This provides a positional feed-back enabling a position control independent of in ⁇ fluence of temperature fluctuation, so that coincidence between desired conditions and actual conditions con ⁇ tinuously can be secured.
• the embodiment described above thus illustrates the possibilities available by using the control means according to the present invention e.g. for controlling the fuel injection in a diesel engine in an accurate, rapid and flexible way in order to provide improved efficiency and decreased wear, and at the same time enabling a flexible adjustment to different service conditions.
• the invention which above has been described with reference to an embodiment referring to fuel injection in diesel engines, is by net means limited to this particular field but may be applied in many different fields in which there is a need of accurate control of valves of the kind having a through opening which is steeplessly adjustable by means of a valve member movable within the valve.
• the invention is particularly well adapted for use in valves in which the control movement of the valve member has a limited magnitude in absolute figures, but within the scope of the invention also such embodiments are conceivable, in which the change in length of the magnetostrictive control element is amplified into a movement having an increased magnitude by means of known amplification mechanisms ranging from a simple lever mechanism to more sophisticated systems.

Applications Claiming Priority (2)

Publications (1)

Family

ID=20353416

Family Applications (1)

Country Status (6)

Families Citing this family (21)

Family Cites Families (5)

• 1983
  • 1983-11-22 SE SE8306433A patent/SE8306433L/ not_active Application Discontinuation
• 1984
  • 1984-11-20 AU AU36187/84A patent/AU3618784A/en not_active Abandoned
  • 1984-11-20 WO PCT/SE1984/000396 patent/WO1985002445A1/en not_active Application Discontinuation
  • 1984-11-20 EP EP84904223A patent/EP0189419A1/en active Pending
• 1985
  • 1985-07-17 DK DK325085A patent/DK325085D0/da not_active Application Discontinuation
  • 1985-07-18 NO NO852868A patent/NO852868L/no unknown

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events