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
  • F02M63/0001—Fuel-injection apparatus with specially arranged lubricating system, e.g. by fuel oil
• • 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
  • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
  • F02M37/0047—Layout or arrangement of systems for feeding fuel
  • F02M37/0052—Details on the fuel return circuit; Arrangement of pressure regulators
• • 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
  • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
  • F02M55/04—Means for damping vibrations or pressure fluctuations in injection pump inlets or outlets
• • 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
  • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/0404—Details or component parts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/02—Lubrication
  • F04B39/0284—Constructional details, e.g. reservoirs in the casing
  • F04B39/0292—Lubrication of pistons or cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/18—Lubricating
• • 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
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
• • 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
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
  • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
  • F02M59/102—Mechanical drive, e.g. tappets or cams

Definitions

• the present invention relates to a high pressure fuel pump of a fuel injection equipment and, more particularly to means for attenuating the pressure fluctuations around within the pump.
• a fuel injection equipment is provided with a pump that receives low pressure fuel from a tank and delivers high pressure fuel to fuel injectors.
• the pump typically comprises a pumping head and a cambox, a piston collaborating with a camshaft rotating in the cambox reciprocally slides in a bore of the head to vary the volume of a compression chamber wherein majority of the fuel is pressurised and, the complementary portion leaks and lubricates the piston sliding in the bore, the cambox and the bearings of the camshaft.
• Said low pressure fuel forms return flows that merge prior to exit the pump to return to the tank. Pressure fluctuations generated by the reciprocal displacement of the piston propagate in said return flows and alter the performance of the pump. Damping systems generally arranged within the return line, enable to only partially attenuate said fluctuations, pressure waves still being noticeable within the cambox and around the bearings.
• a high pressure fuel pump of a fuel injection equipment of an internal combustion engine having a housing defining a cambox in which a camshaft is arranged rotatable between a front bearing aligned with a rear bearing, the camshaft cooperating with a piston sliding in a bore to alternatively vary the volume of a compression chamber.
• part of the inlet flow lubricates the front and rear bearings or the piston and the bore, said lubricating flow circulating in a plurality of channels, comprising a front channel and a rear channel joining into a single bearing channel and, in a central channel, said channels being defined in the pump housing and merging prior to join an outlet adapted to be connected to a return line.
• the pump further comprises a venturi arranged in said return channels, the venturi pulling fuel from the bearings and lowering the pressure in the front and rear bearing channels.
• all the channels merge into said venturi.
• the venturi has a diabolo shape conduit with a large section inlet portion narrowing to a central portion forming a restriction which connects to an outlet portion having an enlarging section.
• the venturi is arranged so the return flow from the front and rear bearings both enter the inlet portion.
• the return flow from the cambox directly enters the central portion.
• venturi is defined a cylindrical member inserted in a recess provided in the housing.
• said recess opens in an outer face of the housing, the recess defining a cylindrical peripheral face extending from said opening to an opposed bottom face.
• the front, rear and single bearing channels open in said bottom face. In use, the fuel lubricating the bearings flows in said channels
• the central channel opens in said peripheral face, the cambox lubricant flowing, in use, in said central channel.
• the venturi is a distinct cylindrical member having a cylindrical outer face extending from a transverse under face to a transverse outer face, the venturi inlet portion opening in the under face and, the enlarging outlet portion opening in the outer face.
• the venturi member is further provided with another connecting channel extending radially from the cylindrical outer face to the central restricted portion of the venturi.
• said cylindrical outer face further defines an annular space, said another connecting channel opening in said annular space.
• the venturi is inserted in the recess provided in the housing, the under face of the venturi being against the bottom face of the recess, the return channel opening in said recess peripheral face facing the annular space of the venturi.
• the pump further comprises a return connection member arranged on said recess and protruding from the housing.
• connection member is a tubular member adapted to complementary receive a return line.
• Figure 1 is a general sketch of a high pressure fuel pump as per a first embodiment in which is arranged a damper as per the invention.
• Figure 2 is a general sketch of a high pressure fuel pump as per a second embodiment in which is arranged a damper as per the invention.
• Figure 3 is a plot of the lubricant pressure fluctuations when there is no damper.
• Figure 4 is similar to figure 3 but with a damper.
• Figure 5 is a section of a housing of a fuel pump enabling to visualise the return flow channels and an embodiment of the venturi damper.
• Figure 6 is a magnified view of the venturi of figure 5.
• a fuel injection equipment 10 of an internal combustion engine comprises a pump 12 pressurising and delivering to injectors fuel received from a low pressure tank.
• a typical pump 12 sketched on figures 1 and 2 has a pumping head 14 fixed on a cambox 16 wherein a camshaft 18 aligned between a front 20 and a rear bearing 22 cooperates with a piston to reciprocally slide in a guiding bore for varying the volume of a compression chamber arranged in the pumping head 14.
• figures 1 and 2 differ by the position of a general fuel inlet 24 and the routing of the inlet flow inside the pump.
• said inlet 24 is arranged in the pumping head 14 and the fuel directly gets in the compression chamber.
• said inlet 24 is arranged in the cambox 16 then the fuel upwardly transfers to the compression chamber.
• a majority of the fuel entering the pump 12 is pressurized then expelled via an outlet 26, a smaller portion forming a lubricating flow splits for lubricating the piston-and-camshaft cooperation means, the front bearing 20 and the rear bearing 22.
• said lubricating flow follows a central channel 28 as from the cambox 16, a front channel 30 as from the front bearing 20 and, a rear channel 32 as from the rear bearing 22, said channels 28, 30, 32 converging toward a damper 34 arranged before a return outlet 36 connected to the tank via a return line.
• the damper 34 is a venturi defining a restriction through which the return fuel flow goes and, due to the traditional venturi effect, the venturi pulls in fuel from the bearings, lowering the pressure in the front 30 and rear 32 bearing channels said low pressure on the backleak side of the bearings 20, 22 providing an opportunity to reduce the bearing clearance as now there is more of a pressure differential and therefore more cooling/lubricating flow.
• a section of the housing 38 of the cambox 16 enables to visualise an inner space wherein cooperate, in use, the piston and the camshaft, the two bearings, the three channels 28, 30, 32, the damper 34 and the return outlet 36.
• the damper 34 is an elongated cylindrical member inserted in a deep recess 40 having a cylindrical peripheral face 42 extending from a bottom face 44 to an opening 46 in an outer face of the housing 38.
• the front 30 and rear 32 channels extending from the front and rear bearings merge in a T-junction and form a single bearing channel 33 that opens in said recess bottom face 44 and, the central channel 28 extends directly from said pump inner space and radially opens in the recess peripheral face 42.
• the damper 34 is arranged in said recess 40 together with a return outlet connection member 48.
• Said connection member 48 is a tubular member having an inner portion 50 inserted with press-fit in the recess 40, so that it is fixed to the housing 17 and, a protruding outer potion 52 ready for connection to a hose of the return line.
• Said connection member 48 defines an outlet channel 54 extending through both inner and outer portions and it is further provided with a collar 56 arranged between the inner 50 and the outer 52 portions, said collar 56 defining an annular outer shoulder face 58 abutting against the outer face of the housing around the opening 46 of the recess.
• the outlet channel 54 is larger within the inner portion 50 than within the outer portion 52 so that an inner shoulder face 60 is defined in planar continuity with the outer shoulder face 58 although said planar continuity is not an obligation.
• the damper 34 has a cylindrical peripheral face 62 extending between transverses under 64 and outer 66 faces and, said damper 34 is inserted in the inner portion of the outlet channel 54 so the outer face 66 abuts against the inner shoulder face 60 and, the under face 64 is in close proximity to the recess bottom face 44.
• an upper O-ring 68 is arranged between the damper peripheral face 62 and the inner face of the outlet channel 54 and, a lower O-ring 70 is arranged between the damper peripheral face 62 and the peripheral face 42 of the recess so that, as per the arbitrary orientations of the figures, the central channel 28 opens between said two O-rings 68, 70.
• the damper 34 itself defines a through conduit opening in both under 64 and outer faces 66, said through conduit defining the venturi with a large lower inlet portion 72 opening in the under face 64, a central restriction portion 74, an enlarging outlet portion 76 opening in the outer face 66 and, at least one radial channels 78, two being shown on the figures, extending between the damper peripheral face 62 and said restriction portion 74.
• the opening of the inlet portion 72 faces the opening of the bearing channels 33 in the recess bottom face 44 and, both openings have substantially equal cross-section, for instance typically about 5 mm in diameter.
• Said inlet portion 72 is rather short, maybe a quarter of the total length of the damper 34 straightly upwardly extending in a constant cross-section, or slightly narrowing, toward a beveled end where said cross section abruptly reduces, for instance from said 5mm diameter to 1 mm diameter.
• the central restriction portion 74 is a calibrated orifice extending on an even shorter length, maybe a tenth of the length of the damper and keeping constant said reduced section, for instance 1mm.
• the outlet portion 76 that is lengthy portion upwardly extending and gradually enlarging from a narrow extremity wherein opens the central restriction to a large opening in the outer face of the damper, said large opening having a cross-section substantially equal to the section of the tubular outer portion 52 of the connection member 48.
• the radial channels 78 are calibrated orifices with constant small diameters, substantially equal to the section of the central restriction portion 74, and joining said central portion 74 very near its end where said central portion 74 opens in the narrow end of the outlet portion 76.
• the peripheral face 62 of the damper comprises a long upper portion having a slightly reduced diameter in comparison to a short bottom portion that is a little larger, the upper O-ring 68 being arranged in the upper portion and the lower O-ring 70 being in the bottom portion.
• annular space 80 surrounding the damper 34, the central channel 28 and the radial channels 78 opening in said annular space 80.
• the central flow from the cambox 16 enters the recess 40 in said annular space 80 and, from there it gets into the radial channels 78 and into said outlet portion 76. All the return flow enter the narrow end of the outer portion 76 where said gradually enlarging long outer portion 76 favors mixing of the flows.
• the radial channels 78 are angularly drilled relative to the main axis on the damper conduit. This enables the flow coming from the cambox to more easily merge into the flow from the bearings than a 90° I n junction.
• the central restriction 74 serves majorly to attenuate the pressure fluctuations in the bearing areas while the fluctuations in the cambox are attenuated by the small section radial channels.
• venturi for instance one arranged in the front channel for the flow of the front bearing, one in the rear channel for the flow of the rear bearing and a third venturi in the central channel for the flow of the cambox.
• said venturi can either one or many can be provided integral to the pump housing.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=57993789

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (10)

• 2016
  • 2016-11-17 GB GB1619492.0A patent/GB2556078B/en active Active
• 2017
  • 2017-11-15 WO PCT/EP2017/079248 patent/WO2018091488A1/en unknown
  • 2017-11-15 EP EP17801432.0A patent/EP3542048A1/de not_active Withdrawn

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