EP1024282B1 - Procédé et dispositif de commande d' une pompe à haute pression à débit variable - Google Patents

Procédé et dispositif de commande d' une pompe à haute pression à débit variable Download PDF

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Publication number
EP1024282B1
EP1024282B1 EP20000100854 EP00100854A EP1024282B1 EP 1024282 B1 EP1024282 B1 EP 1024282B1 EP 20000100854 EP20000100854 EP 20000100854 EP 00100854 A EP00100854 A EP 00100854A EP 1024282 B1 EP1024282 B1 EP 1024282B1
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EP
European Patent Office
Prior art keywords
pressure
fuel
control
chamber
valve
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EP20000100854
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German (de)
English (en)
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EP1024282A2 (fr
EP1024282A3 (fr
Inventor
Ken c/o Denso Corporation Uchiyama
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Denso Corp
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Denso Corp
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Publication of EP1024282A3 publication Critical patent/EP1024282A3/fr
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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
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • 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
    • F02M39/00—Arrangements of fuel-injection apparatus with respect to engines; Pump drives adapted to such arrangements
    • F02M39/02—Arrangements of fuel-injection apparatus to facilitate the driving of pumps; Arrangements of fuel-injection pumps; Pump drives
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/14—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons
    • F02M41/1405—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis
    • F02M41/1411—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis characterised by means for varying fuel delivery or injection timing
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/14—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons
    • F02M41/1405—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis
    • F02M41/1411—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis characterised by means for varying fuel delivery or injection timing
    • F02M41/1427—Arrangements for metering fuel admitted to pumping chambers, e.g. by shuttles or by throttle-valves
    • 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

  • a common rail-type fuel injection system is known as one of systems which inject fuel into diesel engines.
  • a common accumulation chamber (common rail) communicating with each engine cylinder is provided.
  • the fuel pressure in the accumulation chamber is maintained at a predetermined pressure by pressure-feeding of fuel the necessary amount of high pressure fuel from a variable discharge-type high pressure pump to the accumulation chamber.
  • the high pressure fuel in the accumulation chamber is injected into the combustion chamber of each cylinder from an electromagnetically-operated injector at a predetermined injection timing.
  • the variable discharge-type high pressure pump has a pressure chamber which is connected to the common rail and increases/decreases its displacement or volume. The amount of fuel sucked into the pressure chamber is adjusted by opening and closing of a control valve provided between the pressure chamber and a low pressure pump which feeds low pressure fuel.
  • a pre-stroke type is generally used to produce the desired feed amount to the common rail by closing the control valve at a predetermined timing when the displacement of the pressure chamber is decreased to set the amount of fuel in the pressure chamber.
  • the control valve is required to operate with high accuracy under high pressure condition because high pressure of fuel is applied to the control valve. The system becomes large and cost increases, if a sufficient pressure-feed amount control characteristics is required.
  • a variable discharge-type high pressure pump is proposed as shown in Fig. 18 to solve this problem.
  • a drive shaft 101 is extended through and held in a pump housing 100.
  • the low pressure fuel is fed into a fuel reservoir 105 from a low pressure pump (feed pump) 102 which rotates with the drive shaft 101 through low pressure fuel passages 103 and 104.
  • An inner cam 106 is formed integrally with the right end part of the drive shaft 101.
  • the left end part of a head 107 is press-inserted into the inner cam 106.
  • Four cylinders 108 (only two are shown in the figure) are formed in radial directions in the left end part of the head 107.
  • a plunger 109 is disposed reciprocally in each cylinder 108.
  • a pressure chamber 110 is defined by the radial inside end surface of the plunger 109 and the inside wall of the cylinder 108, so that fuel introduced therein may be pressurized by reciprocal movement of the plunger 109.
  • a control valve 111 and a suction valve 112 are disposed from the upstream side in the flow passage extending from the fuel reservoir 105 to the pressure chamber 110.
  • the control valve 111 is an electromagnetic valve the power-on or energization of which is controlled by an electronic control unit not shown.
  • the suction valve 112 is a check valve which allows fuel to flow in the forward direction, that is, from the control valve 111 to the pressure chamber 110.
  • the suction valve 112 opens when the pressure in the pressure chamber 110 decreases in response to opening of the control valve 111 and increase of the displacement of the pressure chamber 110 due to rearward movement of the plunger 109. It closes when the control valve 111 closes.
  • the flow passage to the pressure chamber 110 is closed by the suction valve 112 from the start of pressurizing the low pressure fuel to the end of pressure-feeding of fuel, after preliminarily supplying the required amount of fuel from the feed pump 102 to the pressure chamber 110 in accordance with the valve opening period of the control valve 111.
  • the pressure applied to the control valve 111 is limited at a maximum to the feed pressure (about 15 atms). Therefore, the control valve 111 need not be the type which operates with high accuracy under high pressure conditions, so that a sufficient common rail pressure control may be attained in low cost.
  • a valve opening period command value of the control valve 111 is determined in accordance with a fuel injection amount which is the discharge amount of high pressure fuel from the common rail and the control valve 111 is opened and closed in response to the command value to refill the common rail with high pressure fuel (see EP-A-0 816 672).
  • the present invention has been made in view of the above problem, and has an object to provide a control method and apparatus for variable discharge-type high pressure pumps so that excessive pressure-feeding of fuel is prevented and controllability of pressure in an accumulation chamber is improved.
  • a control valve is controlled in accordance with a command value which is indicative of the amount of flow of fuel, and an accumulation chamber is refilled with high pressure fuel in accordance with the amount of high pressure fuel discharged from a pressure chamber.
  • the control requirement includes that a detected actual pressure is higher than a target pressure of the accumulation chamber by more than a predetermined tolerance value and the control valve is disabled to open thereby preventing suction of the low pressure fuel into the pressure chamber, when it is determined that the control requirement is satisfied.
  • control valve is disabled to open when the control requirement is satisfied to indicate a high possibility that air is admixed in the fuel discharged from the low pressure pump.
  • no air is discharged from the low pressure pump into the flow passage part leading from the control valve to the check valve, so that excessive pressure-feeding of fuel into the accumulation chamber is prevented.
  • a control method for a variable discharge-type high pressure pump according to the present invention is described with reference to a case in which it is applied a common rail-type fuel injection system for diesel engines.
  • a plurality of injectors I is mounted on an engine E in correspondence with the combustion chamber of each cylinder. These injectors I are connected to a common rail R which is an accumulation chamber common to each cylinder. The injection of fuel from the injector I into the combustion chamber of the engine E is controlled by on-off of an injection control electromagnetic valve B1. Fuel in the common rail R is injected into the engine E during a period the electromagnetic valve B1 is open. It is assumed that the engine E is a four cylinder-type.
  • a variable discharge-type high pressure pump P is connected to the common rail R through a supply pipe R1 and discharge valves B2, so that fuel is continuously accumulated in the common rail R at a high predetermined pressure which corresponds to a fuel injection pressure.
  • the variable discharge-type high pressure pump P pressurizes low pressure fuel sucked from a fuel tank T by a feed pump P1 to high pressure so that fuel in the common rail R is controlled to the predetermined high pressure.
  • the common rail injection system has an electronic control unit C.
  • the electronic control unit C is constructed with a generally known hardware including a CPU and the like. It produces control signals to the injectors I and the variable discharge-type high pressure pump P in response to inputs from various sensors S1, S2 and S3, so that the injectors I and the variable discharge-type high pressure pump P may be electronically controlled.
  • the electronic control unit C receives engine condition information from, for instance, engine rotation sensor S2 and cylinder discrimination sensor (G1 sensor) S3.
  • the pressure sensor S1 is disposed on the common rail R to detect a common rail pressure, so that information of the common rail pressure is applied to the electronic control unit C.
  • the electronic control unit C calculates optimum injection timing and injection amount (injection period) in response to those information, and produces a control signal to the fuel injection control electromagnetic valve B1 so that the discharge amount of the variable discharge-type high pressure pump P is controlled.
  • variable discharge-type high pressure pump P is shown in detail in Fig. 2.
  • a drive shaft D which is driven to rotate by the engine E at a one-half rotation speed of the engine is inserted into and supported by a pump housing 1.
  • a pump timing pulley 51 is fixed to the left end part of the drive shaft D so that it may be driven to rotate by a timing belt 52 looped over the outer periphery as shown in Fig. 3.
  • a camshaft timing pulley 53 is fixed to the camshaft of the engine, and a crankshaft timing pulley 54 is connected to the crankshaft of the engine.
  • the pump timing pulley 51 and the camshaft timing pulley 53 are driven to rotate by rotation of the crankshaft of the engine through the timing belt 52.
  • Idlers 55 and 56 are used, so that the idler 56 applies a tension to the timing belt 52 with the spring force of a spring 57 to prevent slacking.
  • a vane-type feed pump P1 is coupled with the drive shaft D to supply fuel under low pressure.
  • the feed pump p1 rotates with the drive shaft D to suck fuel from the fuel tank T and feeds it at a predetermined feed pressure (about 15 atms) to a fuel reservoir 5a formed inside a head 14 through low pressure flow passage 11, 12 and a low pressure flow passage 13 in the head 14.
  • the fuel discharge side and the fuel suction side of the feed pump P1 are connected through a pressure regulating valve not shown, so that the discharge pressure may be regulated.
  • the variable discharge-type high pressure pump P houses therein the feed pump P1 shown in Fig. 1.
  • the drive shaft D is supported rotatably in the pump housing 1 through bearings D1 and D2.
  • An inner cam 8 is integrally formed on its right end part.
  • the head 14 is press-fit into the right end opening of the pump housing 1.
  • the head 14 has a protrusion at its left end central part to be inserted into the inner cam 8.
  • a control valve 6a is disposed in the lower end part of the head 14 to control the amount of low pressure fuel flowing into the pressure chamber, that is, to control the amount of fuel passing between the feed pump P1 and a suction valve 4a described later.
  • the suction valve 4a which is a check valve, is disposed in the right end central part of the head 14.
  • a delivery valve 3 is disposed above the suction valve 4a.
  • another control valve 6b and suction valve 4b are disposed at different positions in addition to the control valve 6a and the suction valve 4a.
  • the head 14 is formed with a flow passage 72 leading from the control valve 6a to the suction valve 4a, flow passages 30a and 40a leading from the suction valve 4a to a pressure chamber 23a described later, a discharge port 16a leading from the flow passage 40a to the delivery valve 3.
  • the head 14 is also formed with a flow passage 72 leading from the control valve 6a to the suction valve 4b, flow passages 30b and 40b leading from the suction valve 4b to a pressure chamber 23b described later, a discharge port 16b leading from the flow passage 40b to the delivery valve 3.
  • the control valve 6a is an electromagnetic-type, and has a housing 61 accommodating a coil 62 therein and a valve body 68 press-fit into the upper end part of the housing 61.
  • a valve member 73 is held slidably in a cylinder 69 formed in the valve body 68.
  • the control valve 6a is fixed by threading bolts not shown through a flange 63 provided on the outer periphery of the housing.
  • An annular flow passage 74a is formed around the upper end part of the valve member 73. The flow passage 74a is communicated with the fuel reservoir 5a through the flow passage 74b, and with the flow passage 72 leading to the suction valve 4a through a flow passage 74c.
  • An armature 64 is press-fit fixed to the lower end of the valve member 73 in such a manner that the armature faces a stator 65 with a fixed spacing therebetween.
  • the coil 62 is disposed outside the stator 65.
  • a spring 67 is disposed in a spring chamber 66 formed inside the stator 65 to bias the armature upward in the figure.
  • a generally conical seat surface 75 is formed in the open end of the flow passage 74c so that the top end part of the valve member 73 seats on the seat surface 75 to interrupt the flow passages 74a and 74c under the shown condition that the coil 62 is not powered on.
  • the coil 62 is powered on or energized in response to the control signal from the electronic control unit C, the armature 64 is attracted and the top end part of the valve member 73 integral with the armature 64 leaves away from the seat surface 75 so that the flow passages 74a and 74c are opened. It is advantageous to disable pressure-feeding of fuel at the time of breakage of the coil by thus constructing the control valve 6a to close normally, that is, when not powered on.
  • the control valve 6b is constructed similarly, although not shown.
  • a first cylinder 2a and a second cylinder 2b are formed in the left end central part of the head 14 to define pressure chambers inside the head 14.
  • the cylinder 2a and the cylinder 2b are spaced apart with a spacing therebetween in the axial direction of the drive shaft D, so that the axes of the cylinders 2a and 2b cross perpendicularly to each other. Further, the cylinders 2a and 2b are formed in the direction perpendicular to the axis of the drive shaft D.
  • a first pair of plungers 21a and 21c are disposed to face each other in the first cylinder 2a, and are supported reciprocably and slidably relative to the cylinder 2a.
  • the space defined by the inside wall surface of the cylinder 2a and the end faces of the plungers 21a and 21c provide a first pressure chamber 23a.
  • a second pair of plungers 21b and 21d are disposed to face each other in the second cylinder 2b, and are supported reciprocably and slidably relative to the cylinder 2b.
  • the space defined by the inside wall surface of the cylinder 2b and the end faces of the plungers 21b and 21d provides a second pressure chamber 23b.
  • one plunger 21a is formed shorter than the other plunger 21c.
  • the pressure chamber 23a is located at a position slightly displaced from the center of the cylinder 2a.
  • the plunger 21d is formed shorter than the other plunger 21b, and the pressure chamber 23b is formed at a position slightly displaced from the center of the cylinder 2b.
  • Shoes 24a to 24d are provided at outside end parts of the plungers 21a to 21d.
  • Cam rollers 22a to 22d are supported rotatably on the corresponding shoes 24a to 24d.
  • the end surfaces of the shoes 24a to 24d are slidable on a shoe guide 15 and a plate 7.
  • the shoe guide 15 and the plate 7 are fixed to the head 14 with bolts not shown.
  • a washer 76 is inserted between the plate 7 and the drive shaft D, so that the drive shaft D and the washer 6 are rotatable from each other and the washer 6 and the plate 7 are rotatable from each other.
  • the inner cam 8 is provided in common relative to the cylinders 2a and 2b, so that the plunger 21a to 21d may be reciprocaly moved within the cylinders 2a and 2b by the rotation of the inner cam 8.
  • the inside circumferentail surface of the inner cam 8 is shaped in a cam surface 81 having a plurality of cams.
  • the cam rollers 22a to 22d are disposed so that the outside circumferences of the cam rollers 22a to 22d are in sliding contact with the cam surface 81.
  • the inside circumferential surface of the inner cam 8 is shaped in an elliptic form, and two cams are formed at equal intervals (at positions to face the plungers 21a and 21c in Fig. 5(A)).
  • the suction valve 4a which has the flow passage 43 passing through the housing 42 in the left and right directions and a valve member 44 for opening and closing the flow passage 43.
  • the flow passage 43 is enlarged in the middle of its extension in the direction of the pressure chamber 23a (leftward in the figure) to form a conical seat surface 45.
  • the valve member 44 is biased in the right direction by a spring 46 held in a spring stopper 41, and seats on the seat surface 45.
  • the check valve 4a is normally closed in the normal condition shown in the figure.
  • the check valve 4a is so constructed that it opens when the control valve 6a opens to allow low pressure fuel to flow from the fuel reservoir 5a and decrease the pressure in the flow passage 30a (pressure in the pressure chamber 23a).
  • the low pressure fuel flows into the pressure chamber 23a through the flow passage 72, annular flow passage 48 provided around the outside circumference of the housing 42, flow passage 49 in the housing 42, flow passage 43, flow passage 50 in the spring stopper 41, and flow passages 30a, 40a provided in the head 14.
  • suction valve 4b not shown in Fig. 4 is constructed similarly as the suction valve 4a. As described later, the suction valve 4b also opens when the control valve 6b opens to allow low pressure fuel to flow from the fuel reservoir 5b and decrease the pressure in the flow passage 30b (pressure in the pressure chamber 23b). Low pressure fuel flows into the pressure chamber 23b through the flow passage 72, annular flow passage 48 provided around the outside circumference of the housing 42, flow passage 49 in the housing 42, flow passage 43, flow passage 50 in the spring stopper 41, and flow passages 30b, 40b provided in the head 14. The suction valves 4a and 4b are fixed in the head 14 with screws 47.
  • the delivery valve 3 has a check valve function and has balls 31a and 31b as valve members.
  • the ball 31a is constructed to open and close the flow passage leading from the discharge port 16a communicated with the pressure chamber 23a
  • the ball 31b is constructed to open and close the flow passage leading from the discharge port 16b communicated with the pressure chamber 23b.
  • the second pressure-feeding route comprises the cylinder 2b, a pair of plungers 21b, 21d and pressure chamber 23b surrounded by those.
  • the first pressure-feeding route and the second pressure-feeding route alternately attain fuel pressure-feeding operation.
  • the pressure chamber 23a is communicated with the side of the ball 31a of the delivery valve 3 through the flow passage 40a and the discharge port 16a
  • the pressure chamber 23b is communicated with the side of the ball 31b of the delivery valve 3 through the flow passage 40b and the discharge port 16b.
  • the ball 31a or the ball 31b opens when the pressure in fuel pressurized in each pressure chamber 23a, 23b, so that fuel is supplied to the common rail R through the supply pipe R1.
  • the fuel is discharged alternately through the balls 31a and 31b, because the fuel in the pressure chambers 23a and 23b is pressurized alternately.
  • the feed pressure to the common rail R varies with operating conditions of the engine E between 200 to 1200 atms.
  • the supply system of low pressure fuel to the pressure chambers 23a and 23b has two routes, one being from the fuel reservoir 5a to the pressure chamber 23a through the control valve 6a, suction valve 4a and the flow passage 30a and the other being from the fuel reservoir 5b to the pressure chamber 23b through the control valve 6b, suction valve 4b and the flow passage 30b.
  • cam #1 indicates a lift amount at the points 81a and 81c on the cam surface 81 which faces the plungers 21a and 21c in Fig. 5(A).
  • Cam #2 indicates a lift amount at the points 81b and 81d on the cam surface 81 which faces the plungers 21b and 21d in Fig. 5(B).
  • TCV #1 indicates a lift amount of the valve member 73 of the control valve 6a
  • TCV #2 indicates a lift amount of the valve member 73 of the control valve 6b.
  • the cams #1 and #2 repeats radially inward movement and radially outward movement. Because the cylinders 2a and 2b are formed perpendicularly to each other, the cams #1 and #2 are different 180° CA (crankshaft angle) in phase.
  • the other pressure chamber 23b (23a) is in the fuel pressure-feeding operation.
  • the electronic control units C starts to power on the coil 62 of the control valve 6a in advance before the valve member 73 of the control valve 6a opens at the time of start of moving of the cam #1 in the radially outward direction.
  • fuel flows into the pressure chamber 23a from the fuel reservoir 5a through the flow passages 74c, 72 of the control valve 6a, flow passage 43 of the suction valve 4a and flow passages 30a, 40a.
  • the plungers 21a and 21c move in the radially outward direction while being pressed down onto the cam surface 81 by the fuel flowing thereinto, so that fuel is sucked as the displacement of the pressure chamber 23a is increased.
  • the cam #1 moves to come into the fuel pressure-feeding operation.
  • the plungers 21a and 21c do not start moving in the radially inward direction immediately after the cam #1 starts moving for fuel pressure-feeding operation.
  • the cam rollers 22a and 22c abut the inner cam 8 to drive the plungers 21a and 21c to move in the radially inward direction through the shoes 24a and 24c.
  • the suction valve 4a is closed.
  • the control valve 6b is powered on with about 180° CA delay from the control valve 6a in the above period, the cam #2 starts moving to effect suction and fuel pressure-feeding operation in the pressure chamber 23b in the same manner as in the pressure chamber 23a.
  • a maximum driving torque is reduced by differentiating the time points of fuel pressure-feeding operation between the pressure chambers 23a and 23b.
  • control method for preventing excessive pressure-feeding of fuel to the common rail R is described with reference to flow diagrams of controlling the variable discharge-type high pressure pump P executed in the electronic control unit C.
  • a NE-signal hardware interrupt routine is executed at every input of the NE-signal produced 68 times per 720° CA.
  • a pulse interval between the input NE-signal and the previous one is measured at step S101, so that the pulse interval may be used in a calculation of engine rotation speed Ne.
  • a software interrupt process is called at step S105 in correspondence with CNIRQ, thus ending the NE-signal hardware interrupt routine.
  • the cylinder counter PCYLND 0 is set in response to an input of G1-signal from the G1 sensor S3.
  • a software interrupt process called at step S105 is described.
  • a command injection amount QF of the injector I is calculated at step S202, and a command injection timing AF is calculated at step S203 based on the command injection amount QF and the engine rotation speed Ne.
  • a target common rail pressure PF is calculated at step S204 based on the command injection amount QF and the engine rotation speed Ne.
  • the common rail pressure PC is read in at step S301, and a power-on period TQF to the injector I is calculated at step S302 based on the actual common rail pressure PC and the command injection amount QF.
  • a pump power-on period TF is calculated at step S303 to indicate the valve opening period command value as a command value to the control valves 6a and 6b for controlling the amount of fuel passing between the feed pump 1 and the suction valve 4a and between the feed pump P1 and the suction valve 4b.
  • Fig. 11 shows a calculation process of the pump power-on period TF executed at step S303.
  • a basic power-on period TFJP is calculated at step S401 based on the command injection amount QF and the target common rail pressure PF.
  • the subsequent steps S402 to S406 are for calculating corrective terms which are to be added to or subtracted from the command injection amount QF.
  • a proportional compensation amount TFJP is calculated at step S402 from the difference between the common rail pressure PC and the target common rail pressure PF.
  • the above corrective terms operates to shorten the pump power-on period TF.
  • the integral compensation amount TFJI is updated, it results in that the integral compensation value TFJI will in the end includes component which corresponds to the difference between the abnormal common rail pressure PC at this moment and the target common rail pressure PF. Therefore, this updating is not desired.
  • the appropriate compensation amount can be calculated by skipping the updating of the integral compensation amount TFJI based on the above difference at the time of abnormality.
  • An electromagnetic valve closing delay compensation amount TFD is calculated at step S405 to compensate for the response delay of closing operation of the control valves 6a and 6b relative to the valve closing signal (interruption of power-on to the coil 62).
  • the electromagnetic valve closing delay compensation amount TFD is calculated using the following equation (1), that is, by converting the valve closing delay time TFDB ( ⁇ s) of the control valves 6a and 6b stored preliminarily into the crankshaft angle in accordance with the engine rotation speed Ne.
  • TFD TFDB x 6 x Ne x 10 -6
  • the pump power-on period TF is calculated at step S406 using the equation (2).
  • TF TFJB + TFJP + TFJI - TFD + TFOF
  • Fig. 14 shows the power-on process of step S604.
  • the routine ends after setting the power-on flag TFON at step S605 and without executing the above power-on process when the pump power-on period TF is shorter than the lower limit value and the common rail pressure PC is higher than the target common rail pressure PF + tolerance value (steps S601 and S602). That is, if the check results at steps S601 and S602 are both affirmative, no fuel is refilled into the common rail in connection with fuel injection from the injectors.
  • control valve 6a is not opened when the control conditions to be checked at steps S601 and S602 are satisfied.
  • the control valve is opened for a predetermined period in accordance with the required amount of fuel to be refilled in the common rail in connection with the fuel injection from the fuel injector.
  • Fig. 19 showing the conventional method, the control valve is powered on to open at the stage 1 ⁇ .
  • the control valve With the opening of the control valve, low pressure fuel flows into the flow passage part (fuel reservoir part) from the control valve to the suction valve, and the pressure in the fuel reservoir part rises from the atmospheric pressure to the feed pressure.
  • the suction valve As the suction valve is maintained closed, the pressure in the pressure chamber is the same as that in the common rail and the plunger is pressed to the cam surface.
  • the low pressure pump sucks air with fuel from the fuel tank in which the remaining amount of fuel is less such as in fuel shortage condition, air admixes in the fuel supplied to the fuel reservoir part.
  • the cam lift decreases with the plunger being pressed to the cam surface and moving in the radially outward direction.
  • the displacement of the pressure chamber is increased and the pressure in the pressure chamber is decreased.
  • the suction valve is maintained closed, because the pressure in the pressure chamber is higher than the feed pressure.
  • the pressure in the pressure chamber decreases below the feed pressure.
  • the suction valve opens so that low pressure fuel is sucked into the pressure chamber through the suction valve, even when the control valve has already been closed.
  • the pressure in the fuel reservoir part communicated with the pressure chamber further decreases from the feed pressure toward the atmospheric pressure in the same manner as the pressure chamber, and the admixed air in the fuel reservoir part expands. The air expands much more than fuel because of decrease in the pressure, and forces out the fuel in the fuel reservoir part to the pressure chamber.
  • the pressure in the pressure chamber increases further, and exceeds the pressure defined by the valve opening pressure of the delivery valve to open the delivery valve.
  • the fuel is pressure-fed from the pressure chamber to the common rail R. Because the regulation of the suction amount of fuel into the pressure chamber at the excessive amount side has errors as described above, the fuel is fed excessively.
  • the above steps S601 and S602 are executed so that the power-on of the control valve 6a is disabled (step 605) when the influence of shortening of the command power-on period TF and occurrence of excessive pressure-feeding of fuel is large.
  • the excessive pressure-feeding of fuel condition can thus be avoided.
  • good vehicle driveability and less exhaust gas emission can be attained without causing lessening of pressure controllability.
  • variable discharge-type high pressure pump P pressure-feeds fuel to the common rail R alternately from a plurality of pressure chambers 23a and 23b.
  • the suction valves 4a and 4b need be provided for the pressure chambers 23a and 23b in one-to-one correspondence.
  • the flow passage (fuel reservoir part) 73, 74c, 72, 71a, 48, 49 or 73, 74c, 72, 71b, 48, 49 leading from the control valves 6a, 6b to the suction valves 4a, 4b become lengthened.
  • the admixed air which will cause the excessive pressure-feeding of fuel flows into the flow passages, when the feed pump P1 sucks air with fuel. That is, the variable discharge-type high pressure pump P shown in the figures provides an excessive pressure-feeding of fuel preventing effect when controlled according to the control method of the present invention.
  • the lower limit value and the tolerance value at steps S601 and S602 are not necessarily limited to the above values. It is preferred to set the values preliminarily through experiments to match the specifications of the variable discharge-type high pressure pump and the like.
  • Fig. 16 shows a control method for a variable discharge-type high pressure pump according to the second embodiment of the present invention.
  • step S601 for checking the pump power-on period TF in the first embodiment is skipped, and only step S602 is executed.
  • the control conditions for preventing opening of the electromagnetic valves 6a and 6b are limited to only that the common rail pressure PC is higher than the target common rail pressure PF + tolerance value. If affirmative at step S602, the power-on flag TFON is set to 0.
  • the present invention may be applied to not only the above variable discharge-type high pressure pump which is constructed to have a control valve and a suction valve for each of a plurality of pressure chambers, but also other types in which low pressure fuel is fed to a pressure chamber through a control valve and a suction valve.
  • the pump may be so constructed that low pressure fuel fed out from a feed pump and passing through a common control valve 6 flows into a suction valve 4a through a flow passage 71a and into a suction valve 4b through a flow passage 71b.
  • the pump may also be so constructed that the control valve and the suction valve are provided singly for a single pressure chamber as shown in Fig. 18.
  • the opening period of a control valve is controlled to control the amount of fuel flowing between a feed pump and a suction valve.
  • the control valve is not limited to the above type, but may be a linear solenoid valve type which controls its opening area proportionally.
  • the present invention may also be applied to a system in which the amount of fuel is controlled by varying the opening area of the control valve.

Landscapes

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

Claims (7)

  1. Procédé de commande d'une pompe à haute pression à débit variable (P) comprenant une chambre de pression (23a) qui est reliée à une chambre d'accumulation (R) pour contenir un combustible à haute pression et augmente/diminue son déplacement, un clapet anti-retour (4a) qui est placé dans un passage d'écoulement qui s'étend d'un côté basse pression (P1) vers la chambre de pression dans un sens direct depuis le côté basse pression (P1) vers la chambre de pression (23a), et une vanne de commande (6a) qui est placé dans le passage d'écoulement pour contrôler la quantité de combustible qui passe entre le côté basse pression (P1) et le clapet anti-retour (4a), de telle sorte que le combustible à basse pression soit aspiré depuis le côté basse pression (P1) dans la chambre de pression (23a) à travers la vanne de commande (6a) quand la chambre de pression (23a) augmente son déplacement, et le combustible dans la chambre de pression (23a) est alimenté sous pression dans la chambre d'accumulation (R) quand la chambre de pression (23a) réduit son déplacement, le procédé de contrôle comprenant les étapes de :
    commander (S604) la vanne de commande (6a) selon une commande indicative de la quantité de combustible qui passe ; et
    remplir la chambre d'accumulation (R) avec un combustible haute pression selon la quantité de combustible haute pression évacué de la chambre de pression (23a) ; et
    vérifier (S601, S602) si un critère de commande est satisfait, le procédé de commande étant caractérisé en ce que le critère de commande comprend le fait qu'une pression détectée (PC) dans la chambre d'accumulation (R) soit supérieure à une pression cible (PF) dans la chambre d'accumulation (R) de plus d'une valeur de tolérance prédéterminée ; et
    en ce que le procédé de commande comprend également une étape de désactiver (S605) l'ouverture de la vanne de commande (6a), empêchant ainsi l'aspiration du combustible à basse pression dans la chambre de pression (23a), quand il est déterminé que le critère de commande est satisfait.
  2. Procédé de commande selon la revendication 1, dans lequel :
    la vanne de commande (6a) modifie sa durée d'ouverture selon la valeur de la commande ; et
    le critère de commande comprend le fait que la valeur de commande de durée d'ouverture de vanne (TF) de la vanne de commande (6a) est inférieure à une valeur limite inférieure prédéterminée.
  3. Procédé de contrôle selon la revendication 2, dans lequel :
    une compensation intégrale est exécutée (S404, S406) dans un calcul de la valeur de commande de durée d'ouverture de vanne (TF) selon une valeur intégrée d'une différence entre la pression réelle (PC) dans la chambre d'accumulation (R) et la pression cible (RF) ; et
    la mise à jour (S404) de la valeur de compensation intégrale est désactivée quand la vanne de commande (6a) est empêché de s'ouvrir.
  4. Appareil de commande comprenant :
    une pompe à haute pression (P) comprenant une chambre de pression (23a) qui est reliée à une chambre d'accumulation (R) pour contenir un combustible haute pression et augmente/diminue son déplacement ;
    un clapet anti-retour (4a) placé dans un passage d'écoulement qui s'étend depuis un côté basse pression (P1) vers la chambre de pression (23a) dans un sens direct depuis le côté basse pression (P1) vers la chambre de pression (23a) ;
    une vanne de commande (6a) qui est placée dans le passage d'écoulement pour commander la quantité de combustible qui passe entre le côté basse pression (P1) et le clapet anti-retour (4a), de telle sorte que le combustible basse pression soit aspiré depuis le côté basse pression (P1) dans la chambre dè pression (23a) à travers la vanne de commande (6a) quand la chambre de pression (23a) augmente son déplacement, et le combustible dans la chambre de pression (23a) est alimenté sous pression dans la chambre d'accumulation (R) quand la chambre de pression (23a) réduit son déplacement ; et
    une unité de commande électronique (C) pour commander la vanne de commande (6a) selon une commande indicative de la quantité de combustible qui passe et remplir la chambre d'accumulation (R) avec un combustible haute pression selon la quantité de combustible haute pression évacué de la chambre de pression (23a) ;
    l'appareil de commande étant caractérisé en ce que l'unité de commande électronique (C) désactive (S605) l'ouverture de la vanne de commande (6a) pour empêcher ainsi l'aspiration du combustible à basse pression dans la chambre de pression (23a), quand il est déterminé qu'un critère de commande prédéterminé est satisfait, l'exigence de contrôle comprenant le fait qu'une pression réelle (PC) dans la chambre d'accumulation (R) est supérieure à une pression cible (PF) dans la chambre d'accumulation (R) de plus d'une valeur de tolérance prédéterminée.
  5. Appareil de commande selon la revendication 4, dans lequel :
    la vanne de commande (6a) modifie sa durée d'ouverture selon la valeur de la commande ; et
    le critère de commande comprend le fait que la valeur de commande de durée d'ouverture de vanne (TF) de la vanne de commande (6a) est inférieure à une valeur limite inférieure prédéterminée.
  6. Appareil de commande selon la revendication 5, dans lequel :
    l'unité de commande électronique (C) exécute une compensation intégrale dans un calcul de la valeur de commande de durée d'ouverture de vanne (TF) selon une valeur intégrée d'une différence entre la pression réelle (PC) dans la chambre d'accumulation (R) et la pression cible (RF) ; et
    l'unité de commande électronique (C) désactive la mise à jour de la valeur de compensation intégrale (TFJI) quand la vanne de commande (6a) est empêchée de s'ouvrir.
  7. Appareil de commande selon l'une quelconque des revendications 4 à 6, dans lequel :
    la pompe à haute pression (P) est à débit variable (P) et comprend une paire de chambres de pression (23a ; 23b), les chambres de pression (23a ; 23b) étant éloignées l'une de l'autre ;
    une paire de pistons (21a, 21c ; 21b, 21d) placés réciproquement dans chacune des chambres de pression (23a ; 23b) ; et
    chaque paire de pistons (21a, 21c ; 21b, 21d) est disposée pour se croiser de telle sorte que les pistons (21a, 21c) dans une chambre de pression (23a) se déplacent dans un sens opposé aux pistons (21b, 21d) dans l'autre chambre de pression (23b) en réponse à la rotation d'un moteur (E).
EP20000100854 1999-01-28 2000-01-17 Procédé et dispositif de commande d' une pompe à haute pression à débit variable Expired - Lifetime EP1024282B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2038899 1999-01-28
JP2038899 1999-01-28
JP35016899A JP3744290B2 (ja) 1999-01-28 1999-12-09 可変吐出量高圧ポンプの制御方法
JP35016899 1999-12-09

Publications (3)

Publication Number Publication Date
EP1024282A2 EP1024282A2 (fr) 2000-08-02
EP1024282A3 EP1024282A3 (fr) 2003-05-14
EP1024282B1 true EP1024282B1 (fr) 2004-09-15

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EP (1) EP1024282B1 (fr)
JP (1) JP3744290B2 (fr)
DE (1) DE60013657T2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006000459B4 (de) * 2005-09-15 2016-04-07 Denso Corporation Brennstoffeinspritzsteuerungsvorrichtung

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3960051B2 (ja) * 2002-01-15 2007-08-15 株式会社デンソー 蓄圧式燃料噴射装置
JP4513609B2 (ja) * 2005-03-10 2010-07-28 株式会社デンソー 燃料噴射制御装置
JP2007327404A (ja) * 2006-06-07 2007-12-20 Denso Corp コモンレール式燃料噴射装置
JP4605129B2 (ja) * 2006-09-19 2011-01-05 株式会社デンソー 燃圧制御装置

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69720603T2 (de) * 1996-07-05 2004-03-04 Nippon Soken, Inc., Nishio Hochdruckpumpe
JP3287297B2 (ja) * 1998-02-10 2002-06-04 トヨタ自動車株式会社 燃料ポンプの制御装置
DE69925783T2 (de) * 1998-04-15 2006-05-11 Denso Corp., Kariya Brennstoffeinspritzsystem für eine Brennkraftmaschine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006000459B4 (de) * 2005-09-15 2016-04-07 Denso Corporation Brennstoffeinspritzsteuerungsvorrichtung

Also Published As

Publication number Publication date
EP1024282A2 (fr) 2000-08-02
DE60013657D1 (de) 2004-10-21
DE60013657T2 (de) 2005-09-29
EP1024282A3 (fr) 2003-05-14
JP3744290B2 (ja) 2006-02-08
JP2000282938A (ja) 2000-10-10

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