WO2019158302A1 - Pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine - Google Patents

Pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine Download PDF

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Publication number
WO2019158302A1
WO2019158302A1 PCT/EP2019/051217 EP2019051217W WO2019158302A1 WO 2019158302 A1 WO2019158302 A1 WO 2019158302A1 EP 2019051217 W EP2019051217 W EP 2019051217W WO 2019158302 A1 WO2019158302 A1 WO 2019158302A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
section
feed
pumping unit
feeding
Prior art date
Application number
PCT/EP2019/051217
Other languages
French (fr)
Inventor
Benedetto Loiacono
Gianluca CILENTI
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2019158302A1 publication Critical patent/WO2019158302A1/en

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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
    • 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
    • F02M59/20—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
    • F02M59/365—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages valves being actuated by the fluid pressure produced in an auxiliary pump, e.g. pumps with differential pistons; Regulated pressure of supply pump actuating a metering valve, e.g. a sleeve surrounding the pump piston
    • 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
    • F02M59/46—Valves
    • F02M59/464—Inlet valves of the check valve 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
    • 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
    • F02M63/0265—Pumps feeding common rails

Definitions

  • the present invention relates to a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine.
  • the present invention relates to a pumping unit of the type comprising a high-pressure pump, for example a piston pump, designed to feed the fuel to an internal combustion engine; a pre-feed pump, for example a gear pump, designed to feed the fuel from a storage tank to the piston pump; and a hydraulic circuit for connecting together the storage tank, the pre-feed pump, the high- pressure pump and the internal combustion engine.
  • a high-pressure pump for example a piston pump
  • a pre-feed pump for example a gear pump, designed to feed the fuel from a storage tank to the piston pump
  • a hydraulic circuit for connecting together the storage tank, the pre-feed pump, the high- pressure pump and the internal combustion engine.
  • the piston pump comprises a pump body; at least two cylinders formed in the pump body and slidably engaged by respective pistons; and an actuating device for displacing the pistons along the associated cylinders with an alternating rectilinear movement comprising an intake stroke for drawing the fuel into the cylinders and a delivery stroke for supplying the fuel to the internal combustion engine.
  • the two cylinders have respective longitudinal axes which are parallel to each other and are each associated with a respective intake valve for drawing the fuel into the cylinder and with a respective delivery valve for supplying the fuel to the internal combustion engine.
  • the actuating device is configured so as to displace simultaneously a piston with its intake stroke and the other piston with its delivery stroke.
  • the hydraulic circuit comprises a first line for connecting together the storage tank and the gear pump; a second branch for connecting together the gear pump and the piston pump; and a third line for connecting together the piston pump and the internal combustion engine.
  • the second line comprises a feed header and, for each cylinder, a respective intake duct for connecting the feed header to the said cylinder.
  • the hydraulic circuit further comprises an electric metering valve mounted along the feed header of the second line for selectively controlling the instantaneous flow of fuel fed to the piston pump depending on the values of a plurality of operating parameters of the internal combustion engine.
  • the electric metering valve comprises a valve body mounted in the feed header and provided with an inlet for entry of the fuel into the said electric metering valve; and a closing member slidably engaged in the valve body so as to be displaced between a position for opening and a position for closing the inlet.
  • the closing member has a cup-shaped form and is provided with at least one feed hole for allowing the fuel to pass through the said closing member.
  • the electric metering valve further comprises a spring arranged between the valve body and the closing member for displacing, and normally keeping, the closing member in its open position, and an electromagnetic actuator for displacing the closing member from its open position into its closed position.
  • the delivery stroke of each piston causes closing of the associated intake valve.
  • part of the fuel compressed by the associated piston flows out of the associated cylinder firstly along the associated intake duct and then both along the intake duct of the other intake valve and along the feed header.
  • the known pumping units of the type described above have a number of drawbacks mainly due to the fact that: the pressure waves generated along the intake duct of each cylinder by the outflow of fuel from the other cylinder favours the opening and, therefore, delays further the closing of the associated intake valve, increasing the effect described above; and the pressure waves generated along the feed header by the outflow of fuel from the two cylinders favours opening of the closing member of the electric metering valve, adversely affecting feeding of the correct fuel flow to the piston pump and therefore to the internal combustion engine.
  • the object of the present invention is to provide a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine, which does not have the aforementioned drawbacks and is simple and inexpensive to produce.
  • a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine is provided, as claimed in the accompanying claims.
  • Figure 1 is a hydraulic diagram of a preferred embodiment of the pumping unit according to the present invention.
  • Figure 2 is a schematic side view, with parts cross-sectioned, of a detail of the pumping unit of Figure 1.
  • 1 denotes in its entirety a pumping unit for feeding fuel, preferably diesel fuel, from a storage tank 2 to an internal combustion engine 3, in the case in question a diesel combustion engine.
  • the engine 3 comprises a header 4 for distribution of the fuel, commonly referred to by the term “common rail”, and a plurality of injectors 5 connected to the header 4 and designed to atomize the fuel inside associated combustion chambers (not shown) of the said engine 3.
  • the pumping unit 1 comprises a high-pressure pump 6, namely a piston pump, for feeding the fuel to the engine 3; and a low-pressure or pre-feed pump 7, namely a gear pump, for example of the electrically operated type, for feeding the fuel from the tank 2 to the pump 6.
  • the pump 6 comprises a pump body 8 and, in this case, two cylinders 9, which are formed in the pump body 8 and have respective longitudinal axes 10 substantially parallel to each other.
  • the number of cylinders 9 is different from two and the axes 10 are not parallel to each other.
  • the cylinders 9 are slidably engaged by respective pistons 11 movable, under the thrust of an actuating device 12, with an alternating rectilinear movement comprising an intake stroke for drawing the fuel inside the associated cylinders 9 and a delivery stroke for supplying the fuel to the engine 3.
  • the device 12 comprises a cam transmission shaft 13 which is housed inside a first containing chamber 14 formed in the pump body 8 and is designed to displace the pistons 11 with their delivery stroke.
  • the device 12 also comprises, for each piston 11, a respective spring (not shown) which is housed inside a second containing chamber (not shown) formed in the pump body 8 and is designed to displace the said piston 11 with its intake stroke.
  • the shaft 13 is configured so as to displace simultaneously a piston 11 with its intake stroke and the other piston 11 with its delivery stroke.
  • the pumping unit 1 further comprises a hydraulic circuit 15 comprising, in turn, a first line 16 for connecting together the tank 2 and the pump 7; a second line 17 for connecting together the pump 7 and the pump 6; and a third line 18 for connecting together the pump 6 and the header 4.
  • the line 17 is provided with a filtering device 19 for filtering the fuel fed to the cylinders 9 and also has an electric metering valve 20 mounted downstream of the device 19 in a direction 21 of flow of the fuel along the line 17, for selectively controlling the instantaneous flowrate of the fuel fed to the pump 6 depending on the values of a plurality of operating parameters of the engine 3.
  • the line 17 and the line 18 are connected to each cylinder 9 by means of an intake valve 22 and a delivery valve 23, respectively.
  • the circuit 15 also comprises a fourth line 24, which extends between the header 4 and the line 16 and allows the fuel flow which exceeds that needed for the injectors 5 to be discharged into the line 16; and a fifth line 25, which extends between the line 17 and the line 16 and is connected to the line 17 downstream of the electric valve 20 in the direction 21, for feeding to the inlet of the pump 7 the fuel seeping through the electric valve 20 when the said electric valve 20 is closed.
  • the circuit 15 also has a sixth line 26 which extends between the line 17 and the line 24, is connected to the line 17 upstream of the electric valve 20 in the direction 21 and is provided with a valve device 27.
  • the device 27 is configured to control the supply, into the pump body 8 and into the chamber 14, of the fuel flow used to lubricate the cam transmission shaft 13 and the fuel flow in excess of that fed through the electric valve 20.
  • the circuit 15 comprises finally a seventh line 28 for feeding into line 26, and therefore into the tank 2, the fuel seeping through the pump body 8.
  • the line 17 comprises a feed header
  • the electric metering valve 20 comprises a valve body 31 with a tubular shape, which is mounted in the header 29 coaxially with a longitudinal axis 32 of the said header 29 and has an inlet channel 33 with an annular shape, which extends around the axis 32 and communicates with the line 17 so as to feed the fuel through the valve body 31.
  • the valve body 31 is slidably engaged by a closing member 34 which has a cup shaped form, is axially limited by an end wall 35 arranged perpendicularly with respect to the axis 32 and is provided with a plurality of connection holes 36 distributed around the said axis 32.
  • the closing member 34 is movable between an open position, in which the holes
  • the closing member 34 is displaced into, and normally kept in, its open position by a spring 37 and is displaced from its open position into its closed position against the action of the spring 37 by an electromagnetic actuator 38 of the known type engaged with the wall 35.
  • the header 29 comprises a first section 39 extending from the electric valve 20 and downstream of one of the ducts 30 (indicated below by 30a) and a second section 40 extending between the section 39 and the other duct 30 (indicated below by 30b).
  • the section 40 has at least partly, in particular at the inlet of the duct 30b, a fuel through-flow cross-section smaller than a through-flow cross-section for the fuel along the section 39.
  • the two sections 39, 40 have respective through-flow cross-sections with a circular shape and the through-flow cross-section of the section 40 has a diameter smaller than a diameter of the through-flow cross-section of the section
  • the header 29 has a constant through- flow cross-section and is provided with a sleeve inserted inside the said header 29 so as to define the section 40.
  • the pumping unit 1 has a number of advantages mainly associated with the fact that the section 40 defines, with its smaller through-flow cross-section, a constriction of the header 29 able to dampen both the pressure waves generated by the fuel supplied from the duct 30a during closing of the associated intake valve 22 and the pressure waves generated by the fuel supplied from the duct 30b during closing of the associated intake valve 22. Consequently the section 40 ensures a greater operating stability both of the intake valves 22 and of the electric metering valve 20, ensuring correct filling of the cylinders 9 and correct feeding of the fuel to the internal combustion engine 3.

Abstract

In a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine (3), the fuel is fed to at least two cylinders (9) of a high-pressure pump (9) along respective intake ducts (30a, 30b) connected to a feed header (29) having a first section (39) for feeding the fuel to one of the intake ducts (30a) and a second feed section (40) extending between the first feed section (39) and the other intake duct(30b); at least part of the second feed section (40) having a fuel through-flow cross-section smaller than a through-flow cross-section for the fuel along the first feed section (39).

Description

Description
Title
PUMPING UNIT FOR FEEDING FUEL, PREFERABLY DIESEL FUEL, TO AN INTERNAL COMBUSTION ENGINE
The present invention relates to a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine.
In particular the present invention relates to a pumping unit of the type comprising a high-pressure pump, for example a piston pump, designed to feed the fuel to an internal combustion engine; a pre-feed pump, for example a gear pump, designed to feed the fuel from a storage tank to the piston pump; and a hydraulic circuit for connecting together the storage tank, the pre-feed pump, the high- pressure pump and the internal combustion engine.
In the case in question, the piston pump comprises a pump body; at least two cylinders formed in the pump body and slidably engaged by respective pistons; and an actuating device for displacing the pistons along the associated cylinders with an alternating rectilinear movement comprising an intake stroke for drawing the fuel into the cylinders and a delivery stroke for supplying the fuel to the internal combustion engine. The two cylinders have respective longitudinal axes which are parallel to each other and are each associated with a respective intake valve for drawing the fuel into the cylinder and with a respective delivery valve for supplying the fuel to the internal combustion engine.
The actuating device is configured so as to displace simultaneously a piston with its intake stroke and the other piston with its delivery stroke.
The hydraulic circuit comprises a first line for connecting together the storage tank and the gear pump; a second branch for connecting together the gear pump and the piston pump; and a third line for connecting together the piston pump and the internal combustion engine.
The second line comprises a feed header and, for each cylinder, a respective intake duct for connecting the feed header to the said cylinder.
Generally, the hydraulic circuit further comprises an electric metering valve mounted along the feed header of the second line for selectively controlling the instantaneous flow of fuel fed to the piston pump depending on the values of a plurality of operating parameters of the internal combustion engine.
The electric metering valve comprises a valve body mounted in the feed header and provided with an inlet for entry of the fuel into the said electric metering valve; and a closing member slidably engaged in the valve body so as to be displaced between a position for opening and a position for closing the inlet. The closing member has a cup-shaped form and is provided with at least one feed hole for allowing the fuel to pass through the said closing member. The electric metering valve further comprises a spring arranged between the valve body and the closing member for displacing, and normally keeping, the closing member in its open position, and an electromagnetic actuator for displacing the closing member from its open position into its closed position. During use, the delivery stroke of each piston causes closing of the associated intake valve. During closing of each intake valve, part of the fuel compressed by the associated piston flows out of the associated cylinder firstly along the associated intake duct and then both along the intake duct of the other intake valve and along the feed header.
The known pumping units of the type described above have a number of drawbacks mainly due to the fact that: the pressure waves generated along the intake duct of each cylinder by the outflow of fuel from the other cylinder favours the opening and, therefore, delays further the closing of the associated intake valve, increasing the effect described above; and the pressure waves generated along the feed header by the outflow of fuel from the two cylinders favours opening of the closing member of the electric metering valve, adversely affecting feeding of the correct fuel flow to the piston pump and therefore to the internal combustion engine.
The object of the present invention is to provide a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine, which does not have the aforementioned drawbacks and is simple and inexpensive to produce.
According to the present invention a pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine is provided, as claimed in the accompanying claims.
The present invention will now be described with reference to the accompanying drawings which illustrate a non-limiting example of embodiment thereof, in which: Figure 1 is a hydraulic diagram of a preferred embodiment of the pumping unit according to the present invention; and
Figure 2 is a schematic side view, with parts cross-sectioned, of a detail of the pumping unit of Figure 1.
With reference to Figure 1, 1 denotes in its entirety a pumping unit for feeding fuel, preferably diesel fuel, from a storage tank 2 to an internal combustion engine 3, in the case in question a diesel combustion engine. The engine 3 comprises a header 4 for distribution of the fuel, commonly referred to by the term "common rail", and a plurality of injectors 5 connected to the header 4 and designed to atomize the fuel inside associated combustion chambers (not shown) of the said engine 3.
The pumping unit 1 comprises a high-pressure pump 6, namely a piston pump, for feeding the fuel to the engine 3; and a low-pressure or pre-feed pump 7, namely a gear pump, for example of the electrically operated type, for feeding the fuel from the tank 2 to the pump 6.
The pump 6 comprises a pump body 8 and, in this case, two cylinders 9, which are formed in the pump body 8 and have respective longitudinal axes 10 substantially parallel to each other. According to a variant not shown, the number of cylinders 9 is different from two and the axes 10 are not parallel to each other.
The cylinders 9 are slidably engaged by respective pistons 11 movable, under the thrust of an actuating device 12, with an alternating rectilinear movement comprising an intake stroke for drawing the fuel inside the associated cylinders 9 and a delivery stroke for supplying the fuel to the engine 3.
The device 12 comprises a cam transmission shaft 13 which is housed inside a first containing chamber 14 formed in the pump body 8 and is designed to displace the pistons 11 with their delivery stroke. The device 12 also comprises, for each piston 11, a respective spring (not shown) which is housed inside a second containing chamber (not shown) formed in the pump body 8 and is designed to displace the said piston 11 with its intake stroke.
In connection with the above description it should be pointed out that the shaft 13 is configured so as to displace simultaneously a piston 11 with its intake stroke and the other piston 11 with its delivery stroke.
The pumping unit 1 further comprises a hydraulic circuit 15 comprising, in turn, a first line 16 for connecting together the tank 2 and the pump 7; a second line 17 for connecting together the pump 7 and the pump 6; and a third line 18 for connecting together the pump 6 and the header 4.
The line 17 is provided with a filtering device 19 for filtering the fuel fed to the cylinders 9 and also has an electric metering valve 20 mounted downstream of the device 19 in a direction 21 of flow of the fuel along the line 17, for selectively controlling the instantaneous flowrate of the fuel fed to the pump 6 depending on the values of a plurality of operating parameters of the engine 3.
The line 17 and the line 18 are connected to each cylinder 9 by means of an intake valve 22 and a delivery valve 23, respectively. The circuit 15 also comprises a fourth line 24, which extends between the header 4 and the line 16 and allows the fuel flow which exceeds that needed for the injectors 5 to be discharged into the line 16; and a fifth line 25, which extends between the line 17 and the line 16 and is connected to the line 17 downstream of the electric valve 20 in the direction 21, for feeding to the inlet of the pump 7 the fuel seeping through the electric valve 20 when the said electric valve 20 is closed.
The circuit 15 also has a sixth line 26 which extends between the line 17 and the line 24, is connected to the line 17 upstream of the electric valve 20 in the direction 21 and is provided with a valve device 27.
The device 27 is configured to control the supply, into the pump body 8 and into the chamber 14, of the fuel flow used to lubricate the cam transmission shaft 13 and the fuel flow in excess of that fed through the electric valve 20.
The circuit 15 comprises finally a seventh line 28 for feeding into line 26, and therefore into the tank 2, the fuel seeping through the pump body 8. In accordance with that shown in Figure 2, the line 17 comprises a feed header
29 and, for each cylinder 9, a respective intake duct 39 for connecting the header 29 to the said cylinder 9.
The electric metering valve 20 comprises a valve body 31 with a tubular shape, which is mounted in the header 29 coaxially with a longitudinal axis 32 of the said header 29 and has an inlet channel 33 with an annular shape, which extends around the axis 32 and communicates with the line 17 so as to feed the fuel through the valve body 31. The valve body 31 is slidably engaged by a closing member 34 which has a cup shaped form, is axially limited by an end wall 35 arranged perpendicularly with respect to the axis 32 and is provided with a plurality of connection holes 36 distributed around the said axis 32. The closing member 34 is movable between an open position, in which the holes
36 are radially aligned with the channel 33, and a closed position, in which the holes 36 are axially offset with respect to the said channel 33.
The closing member 34 is displaced into, and normally kept in, its open position by a spring 37 and is displaced from its open position into its closed position against the action of the spring 37 by an electromagnetic actuator 38 of the known type engaged with the wall 35.
The header 29 comprises a first section 39 extending from the electric valve 20 and downstream of one of the ducts 30 (indicated below by 30a) and a second section 40 extending between the section 39 and the other duct 30 (indicated below by 30b). The section 40 has at least partly, in particular at the inlet of the duct 30b, a fuel through-flow cross-section smaller than a through-flow cross-section for the fuel along the section 39. In particular, the two sections 39, 40 have respective through-flow cross-sections with a circular shape and the through-flow cross-section of the section 40 has a diameter smaller than a diameter of the through-flow cross-section of the section
39. According to an embodiment (not shown) the header 29 has a constant through- flow cross-section and is provided with a sleeve inserted inside the said header 29 so as to define the section 40.
The pumping unit 1 has a number of advantages mainly associated with the fact that the section 40 defines, with its smaller through-flow cross-section, a constriction of the header 29 able to dampen both the pressure waves generated by the fuel supplied from the duct 30a during closing of the associated intake valve 22 and the pressure waves generated by the fuel supplied from the duct 30b during closing of the associated intake valve 22. Consequently the section 40 ensures a greater operating stability both of the intake valves 22 and of the electric metering valve 20, ensuring correct filling of the cylinders 9 and correct feeding of the fuel to the internal combustion engine 3.

Claims

Claims
1. Pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine (3), the pumping unit comprising a high-pressure pump (6) for feeding the fuel to the internal combustion engine (3), the high-pressure pump (6) comprising at least two cylinders (9) and, for each cylinder (9), a respective piston (11) slidably engaged inside the cylinder (9) and a respective intake valve (22) movable between a position for closing and a position for opening the said cylinder (9); a pre-feed pump (7) for feeding the fuel from a storage tank (2) to the high-pressure pump (6); and a hydraulic circuit (15) for connecting together the storage tank (2), the pre-feed pump (7), the high- pressure pump (6) and the internal combustion engine (3), the hydraulic circuit (15) comprising a feed header (29) for feeding the fuel to the high- pressure pump (6) and, for each cylinder (9), a respective intake duct (30a, 30b) for connecting the feed header (29) to the said cylinder (9), the feed header (29) comprising a first section (39) for feeding the fuel to a first said intake duct (30a) and a second feed section (40) extending between the first intake duct (30a) and a second said intake duct (30b); and being
characterized in that at least part of the second feed section (40) has a fuel through-flow cross-section smaller than a through-flow section for the fuel along the first feed section (39).
2. Pumping unit according to Claim 1, wherein the hydraulic circuit (15) further comprises an electric metering valve (20) mounted along the feed header (29); the first feed section (39) extending between the metering valve (20) and the second feed section (40).
3. Pumping unit according to Claim 1 or 2, wherein the through-flow cross- section of each feed section (39, 40) is circular; the diameter of the through- flow cross-section of the second feed section (40) being smaller than the diameter of the through-flow cross-section of the first feed section (39).
4. Pumping unit according to any one of the preceding claims, wherein the
through-flow cross-section of the second feed section (40) is smaller than the through-flow cross-section of the first feed section (39) at least at an inlet of the second intake duct (30b).
5. Pumping unit according to any one of the preceding claims, wherein the
electric metering valve (20) comprises a valve body (31), which is mounted in the feed header (29), has an inlet (33) for the fuel in the valve body (31) and is slidably engaged by a closing member (34) movable between a position for opening and a position for closing the said inlet (33).
6. Pumping unit according to Claim 5, wherein the electric metering valve (20) further comprises a spring (37) for displacing, and normally keeping, the closing member (34) in its open position and an electromagnetic actuator (38) for displacing the closing member (34) from its open position into its closed position.
7. Pumping unit according to any one of the preceding claims, wherein the hydraulic circuit (15) further comprises a sleeve mounted inside the feed header (29) for defining the through-flow cross-section of the second feed section (40).
PCT/EP2019/051217 2018-02-15 2019-01-18 Pumping unit for feeding fuel, preferably diesel fuel, to an internal combustion engine WO2019158302A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT201800002722A IT201800002722A1 (en) 2018-02-15 2018-02-15 PUMPING GROUP TO FEED FUEL, PREFERABLY DIESEL, TO AN INTERNAL COMBUSTION ENGINE
IT102018000002722 2018-02-15

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Publication Number Publication Date
WO2019158302A1 true WO2019158302A1 (en) 2019-08-22

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT201900015099A1 (en) * 2019-08-27 2021-02-27 Bosch Gmbh Robert PUMPING GROUP TO FEED FUEL, PREFERABLY DIESEL, TO AN INTERNAL COMBUSTION ENGINE

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10361577A1 (en) * 2003-12-23 2005-07-21 Robert Bosch Gmbh Fluid delivery device e.g. for fuel high pressure pump, has development area having cyclically working element with upstream unit and fluid quantity flows by means of variable passage area
EP1982070A1 (en) * 2006-01-26 2008-10-22 Robert Bosch Gmbh High-pressure accumulator body with integrated distributor block
DE102014201597A1 (en) * 2014-01-29 2015-07-30 Robert Bosch Gmbh Fuel line for a low pressure circuit of a fuel injection system, low pressure circuit and fuel injection system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10361577A1 (en) * 2003-12-23 2005-07-21 Robert Bosch Gmbh Fluid delivery device e.g. for fuel high pressure pump, has development area having cyclically working element with upstream unit and fluid quantity flows by means of variable passage area
EP1982070A1 (en) * 2006-01-26 2008-10-22 Robert Bosch Gmbh High-pressure accumulator body with integrated distributor block
DE102014201597A1 (en) * 2014-01-29 2015-07-30 Robert Bosch Gmbh Fuel line for a low pressure circuit of a fuel injection system, low pressure circuit and fuel injection system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT201900015099A1 (en) * 2019-08-27 2021-02-27 Bosch Gmbh Robert PUMPING GROUP TO FEED FUEL, PREFERABLY DIESEL, TO AN INTERNAL COMBUSTION ENGINE
WO2021037842A1 (en) * 2019-08-27 2021-03-04 Robert Bosch Gmbh Pump unit for feeding fuel, preferably diesel, to an internal- combustion engine

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