EP1156207A1 - Pompe pour alimenter en carburant un moteur à combustion interne - Google Patents

Pompe pour alimenter en carburant un moteur à combustion interne Download PDF

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Publication number
EP1156207A1
EP1156207A1 EP00830365A EP00830365A EP1156207A1 EP 1156207 A1 EP1156207 A1 EP 1156207A1 EP 00830365 A EP00830365 A EP 00830365A EP 00830365 A EP00830365 A EP 00830365A EP 1156207 A1 EP1156207 A1 EP 1156207A1
Authority
EP
European Patent Office
Prior art keywords
chamber
fuel
piston
pump
conduit
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP00830365A
Other languages
German (de)
English (en)
Inventor
Tiziano Baroni
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Synerject Italy SRL
Original Assignee
Synerject Italy SRL
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 Synerject Italy SRL filed Critical Synerject Italy SRL
Priority to EP00830365A priority Critical patent/EP1156207A1/fr
Publication of EP1156207A1 publication Critical patent/EP1156207A1/fr
Withdrawn legal-status Critical Current

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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
    • 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
    • F02M37/04—Feeding by means of driven pumps
    • F02M37/043—Arrangements for driving reciprocating piston-type pumps
    • 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
    • F04B53/008—Spacing or clearance between cylinder and 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
    • 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
    • F04B53/04—Draining

Definitions

  • the present invention relates to a pump for feeding of fuel a fuel injection system for internal combustion engines.
  • the pump is suitable for engines with small swept volume.
  • the pumps for feeding a fuel injection system for internal combustion engines take the fuel from a tank located at a certain distance from the engine same. In the car manufacturing field many types of pumps for this purpose are operated by an electric motor.
  • a centrifugal pump for fuel feeding.
  • the use of this type of pump is however limited to the cases wherein the necessary pressure of discharge is less than 1 bar.
  • the pump has not any self-priming capacity with the consequent need of locating it in the fuel tank or at a lower or equal level with respect to it.
  • Vane pumps are also known, such as for example described in GB2166802, which however have a substantial friction between blades and inner surface of the pump body and have, therefore, a considerable power consumption.
  • roller pumps like that described in EP0189639.
  • This type has, however, a reduced compression ring area between the rollers and the cooperating surfaces of the channel and of the vanes of the rotor.
  • the rollers urge at the same time on the surfaces of the cylindrical guide channel and on the vanes of the rotor with the consequent sliding that causes friction and wear of the components.
  • a similar friction is present between the two ends of the rollers and the flat surfaces of the side plates that define the rotor.
  • roller pumps like that described in US4362480, friction and wear are reduced by means of the use of expensive wearproof material and hardened surfaces on which copper-nickel alloys or PTFE are deposited.
  • pumps for fuel are known that use balls as pumping elements.
  • a pump of this type is described in FR2506854.
  • These pumps are particularly expensive since they need a high coupling precision between ball and relative cylinder to limit the leakage caused by a very small sealing surface. Furthermore they require an expensive hemispherical channel for reducing the pressure of contact between balls and guiding channel.
  • a further aspect is that almost all the pumps of the types above described are operated by electric motors crossed by the flow of the fuel that is fed to the motor.
  • a problem connected to this type of electric motor is that, owing to the radial channel, that is narrow with respect to its length, the armature of the motor causes in the fuel, turbulence and vorticity in radial direction that reduce the flow of the fuel same and increase its temperature, thus enhancing the production of vapour that is detrimental to the good operation of the injection system.
  • the flow causes, furthermore, a decrease in the efficiency of the electric motor/pump system.
  • a further type of pump for feeding petrol, used for two- and four-cycle engines, is like that shown in US 4829967.
  • This pump provides one or more pistons that reciprocate through a mechanism of "desmodromic" type.
  • This pump avoids some of the drawbacks previously described but, being provided for fuel pressures of about 300 bar, is particularly expensive for complexity of the structure and for precision of the piston/cylinder coupling; the radial allowance existing between these two elements is about 0.001mm.
  • This pump operated directly by the internal combustion engine in direct phase has, furthermore, the need of a separate lubrication system for feeding oil under pressure to a circular channel made in the middle of the cylinder of the pumping element, in order to avoid fuel leakage towards the lower chamber containing the cam shaft and the driving mechanism.
  • Object of the present invention is to provide a pump for feeding of fuel an internal combustion engine that can be easily manufactured, has a fairly small size, does not require expensive machining or complex assembling, fulfils the required performances and does not present the above described drawbacks with reference to the prior art.
  • the characteristic of the pump is that in the body a first chamber crossed by the conduit and a second chamber are made, both flooded by the fuel, the piston reciprocating towards/from the first and second chamber and having a first end plunging in the fuel in the first chamber and a second end plunging in the fuel in the second chamber. Furthermore the inner diameter of the cylinder exceeds the outer diameter of the at least one pumping piston according to a clearance sufficient to allow a minimum leakage of fuel from the first to the second chamber, whereby the leakage of fuel lubricates the coupling between the piston and the cylinder.
  • a channel is advantageously provided of return of the leaked fuel from the second chamber to the conduit.
  • the clearance between the inner diameter of the cylinder and the outer diameter of the at least one pumping piston is set between 0.010 and 0.030 mm.
  • the conduit comprises a portion, on the side of the suction inlet upstream of the first fuel chamber and hydraulically connected to the first chamber, formed by a plurality of holes arranged along a circumference concentrically to the axis of the suction inlet and with the interposition of a first single-acting valve for determining a one way flow from the suction inlet to the first chamber.
  • the chamber and the conduit portion that is set between the single-acting valves have an overall volume that is less than the swept volume of the piston.
  • the reciprocation stroke of the piston is furthermore longer than four times the diameter of the piston.
  • the second chamber contains advantageously a cam mechanism connected to a driven shaft.
  • the single-acting valve located between the suction inlet and the first chamber is a free ball valve, the stroke of the ball being less than 1/5 of the diameter of the ball.
  • a compensation channel of the peak pressure is advantageously provided that extends between the first chamber and the outlet mouth.
  • a pressure relief valve is present loaded to open at a predetermined value of the pressure of the fuel present in the delivery outlet so that, when a preset value is exceeded, a partial return flow of the fuel from the delivery outlet towards the second chamber is determined.
  • the second chamber can be hydraulically connected to a fuel tank through an opening containing a filter element.
  • the pump comprises a body 1 having a cylinder 2 in which a pumping piston 3 reciprocates whose ends plunge in two chambers of different volume 4 and 5 contained in the same pump body 1.
  • piston 3 At the end on the same side of the chamber of major volume 5 piston 3 is integrally connected to a joint 6 that is connected, by means of a first pin 7 and a connecting rod 8, to a second pin 9 eccentrically integral to shaft 10 of an electric motor 11.
  • connecting rod 8 and pins 7 and 9 may be coupled by needle bearings.
  • the eccentricity of second pin 9 with respect to the axis of shaft 10 of electric motor 11 determines the reciprocation stroke of pumping piston 3.
  • the constancy of said stroke in case of a mass production is assured by the easy structure of the cam system formed by a flattening machined on second pin 9 and on shaft 10 of the engine with the following union of said two parts by means of a strong welding, preferably a laser welding.
  • eccentric pin 9 is formed in one piece with shaft 10 of electric motor 11.
  • Joint 6 that is integral to the pumping piston is, preferably, of plastics and its connection to piston 3 can be preferably done by means of direct injection moulding on it.
  • conduits 12 and 13 are made that are, respectively, the inlet conduit 12 and the outlet conduit 13 of the fuel. Both conduits are hydraulically connected, with the interposition of two single-acting ball valves 14 and 15 and by means of a plurality of narrow ducts 16 and 17, to the chamber of minor volume 4 in which pumping piston 3 plunges.
  • the chamber of major volume 5, wherein the drive mechanism of pumping piston 3 is housed, is furthermore connected, by means of a further conduit 18 made in the body 1 of the pump, to the inlet conduit 12 of the fuel.
  • the chamber of major volume 5 provides an opening 19 of connection with the tank same.
  • a filter 20 is arranged in said opening.
  • the clearance existing between the reciprocating pumping piston 3 and the cooperating cylinder 2 is important for avoiding expensive machining, to limit the leakage, to keep a self-priming capacity and to contain the power consumption, by assuring the presence, between pumping piston and cylinder, of a hydrodynamic bearing determined by the fuel.
  • the sealing area between the two chambers 4 and 5 is proportional to the length of cylinder 2.
  • the above objects are achieved using a diametrical clearance between piston and cylinder set between 0.010 and 0.030 mm. This clearance allows to limit the costs of production avoiding the need of expensive couplings during production and long control steps when assembling.
  • the amount of leaked fuel, and therefore the volumetric efficiency of the pump are preferably controlled providing a length of cylinder 2, and then a sealing area between the two chambers 4 and 5, equal to at least four times the diameter of pumping piston 3.
  • Another parameter for improving the volumetric efficiency is the amount of fuel contained in the space formed by the chamber of minor volume 4 and the plurality of conduits 16 and 17 that connect said chamber to the two single-acting valves 14 and 15.
  • the volume of said amount of fuel must not exceed the swept volume of the pump, calculated as known by the transversal cross section of pumping piston 3 multiplied with the reciprocation stroke.
  • the volume of liquid contained in the space around the chamber of minor volume 4 is also limited by the use, at the suction inlet 12, of a free single-acting ball valve, that avoids the considerably more volume of liquid that would be contained in the space if a spring loaded ball valve were used.
  • the ball of said single-acting valve 14 is centred with respect to the relative recess by the flow of the fuel pushed towards the chamber of minor volume 4 by means of a plurality of conduits 16 arranged along a circumference concentrically to the axis of said recess.
  • the ball of single-acting valve 14 located at suction inlet 12 is associated to a pawl that limits the stroke of the ball to less than 1/5 of the diameter of said ball.
  • a dampening system of the peak pressure is provided, preferably made in the body, suitable for reducing the unevenness of the pressure of fuel fed to the internal combustion engine, as in particular in the case of pumps having a single piston.
  • dampeners located between the feeding pump and the fuel injection system. These dampeners are efficient but their encumbrance creates problems of installation on the vehicle, particularly on motorcycles and mopeds.
  • an embodiment of the pump according to the present invention provides the presence of a conduit 21 made in the body 1' of the pump and hydraulically connecting the zone of the delivery outlet 13' located downstream the relative single-acting valve 15 with the chamber of major volume 5' containing the "desmodromic" cam drive mechanism.
  • a spring loaded pressure relief valve 22 is arranged that opens the flow at a pressure slightly higher than the pressure set by a pressure adjusting device, not shown, that is located on the conduit that connects the pump to the injection system of the internal combustion engine.
  • Valve 22 allows, when a preset value is exceeded, a partial return flow of the fuel from delivery outlet 13' towards the chamber of major volume 5'.
  • the pressure relief valve provides, thus, to cut the significant part of the peak pressure that occurs ad every stroke of the pumping piston and makes easier the equalisation of pressure.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Reciprocating Pumps (AREA)
EP00830365A 2000-05-19 2000-05-19 Pompe pour alimenter en carburant un moteur à combustion interne Withdrawn EP1156207A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP00830365A EP1156207A1 (fr) 2000-05-19 2000-05-19 Pompe pour alimenter en carburant un moteur à combustion interne

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP00830365A EP1156207A1 (fr) 2000-05-19 2000-05-19 Pompe pour alimenter en carburant un moteur à combustion interne

Publications (1)

Publication Number Publication Date
EP1156207A1 true EP1156207A1 (fr) 2001-11-21

Family

ID=8175337

Family Applications (1)

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EP00830365A Withdrawn EP1156207A1 (fr) 2000-05-19 2000-05-19 Pompe pour alimenter en carburant un moteur à combustion interne

Country Status (1)

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EP (1) EP1156207A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103470492A (zh) * 2013-10-11 2013-12-25 湖州三井低温设备有限公司 一种低温高压往复泵进液结构
CN103590943A (zh) * 2013-11-29 2014-02-19 中国第一汽车股份有限公司 一种车用柴油供给系统
IT202000005557A1 (it) * 2020-03-16 2021-09-16 Comet Spa Testata rinforzata per una pompa volumetrica

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2183510A (en) * 1937-11-01 1939-12-12 Timken Roller Bearing Co Fuel pump
US2365237A (en) * 1943-07-20 1944-12-19 Jr Lloyd Allen Fuel pump
US3157221A (en) * 1961-08-07 1964-11-17 Holley Carburetor Co Fluid supply system
DE1280006B (de) * 1966-06-29 1968-10-10 Borg Warner Luftabscheider fuer ein Brennstoff-Foerdersystem
US5899136A (en) * 1996-12-18 1999-05-04 Cummins Engine Company, Inc. Low leakage plunger and barrel assembly for high pressure fluid system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2183510A (en) * 1937-11-01 1939-12-12 Timken Roller Bearing Co Fuel pump
US2365237A (en) * 1943-07-20 1944-12-19 Jr Lloyd Allen Fuel pump
US3157221A (en) * 1961-08-07 1964-11-17 Holley Carburetor Co Fluid supply system
DE1280006B (de) * 1966-06-29 1968-10-10 Borg Warner Luftabscheider fuer ein Brennstoff-Foerdersystem
US5899136A (en) * 1996-12-18 1999-05-04 Cummins Engine Company, Inc. Low leakage plunger and barrel assembly for high pressure fluid system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103470492A (zh) * 2013-10-11 2013-12-25 湖州三井低温设备有限公司 一种低温高压往复泵进液结构
CN103590943A (zh) * 2013-11-29 2014-02-19 中国第一汽车股份有限公司 一种车用柴油供给系统
CN103590943B (zh) * 2013-11-29 2015-10-14 中国第一汽车股份有限公司 一种车用柴油供给系统
IT202000005557A1 (it) * 2020-03-16 2021-09-16 Comet Spa Testata rinforzata per una pompa volumetrica

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