EP1717439A1 - Fuel injection system for internal combustion engines - Google Patents
Fuel injection system for internal combustion engines Download PDFInfo
- Publication number
- EP1717439A1 EP1717439A1 EP06112490A EP06112490A EP1717439A1 EP 1717439 A1 EP1717439 A1 EP 1717439A1 EP 06112490 A EP06112490 A EP 06112490A EP 06112490 A EP06112490 A EP 06112490A EP 1717439 A1 EP1717439 A1 EP 1717439A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fuel
- supply
- injector
- piston
- pump
- 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.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 56
- 238000002347 injection Methods 0.000 title claims abstract description 30
- 239000007924 injection Substances 0.000 title claims abstract description 30
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 22
- 230000009471 action Effects 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 5
- 230000005284 excitation Effects 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 3
- 230000003213 activating effect Effects 0.000 claims 3
- 230000009849 deactivation Effects 0.000 claims 2
- 239000002828 fuel tank Substances 0.000 claims 2
- 238000011144 upstream manufacturing Methods 0.000 claims 1
- 238000006073 displacement reaction Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 4
- 230000004913 activation Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000004513 sizing Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
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- 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
- F02M59/18—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps characterised by the pumping action being achieved through release of pre-compressed springs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/04—Pumps peculiar thereto
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
- F02M51/061—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
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- 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
- F02M57/00—Fuel-injectors combined or associated with other devices
- F02M57/02—Injectors structurally combined with fuel-injection pumps
- F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
- F02M57/027—Injectors structurally combined with fuel-injection pumps characterised by the pump drive electric
Definitions
- the device subject of the present invention falls in the sector of fuel supply systems for internal combustion engines.
- a large part of internal combustion engines is currently supplied with fuel injection systems which, according to applications, have operating pressures varying between 2 bar and 150 bar.
- roller rotary electropumps operated by a direct-current motor (as well as go-devil pumps or liquid-ring pumps) are widely used in the technical practice.
- mechanically-operated alternative pumps are nearly always employed.
- by-pass pressure adjusters are normally employed.
- Fig. 1 shows the diagram of a conventional fuel-injection system.
- the fuel to be processed is drawn from tank 1 and arrives, through a filtering system 2, at pump 3 which provides to pressurise it and to send it to injector 4.
- Injector 4 adjusts the fuel flow, which reaches the engine through the intake manifolds or is directly injected into the combustion chamber.
- Supply pressure adjustment is the task, as already mentioned, of a pressure adjuster 5 which, arranged downstream of the pump, is generally integrated in a by-pass circuit.
- Pressure adjustment through a by-pass system provides for the pump capacity to be oversize, according to the maximum flow rate required by the injector.
- pump capacity is defined according to the value of the flow rate required by the injector upon maximum power delivery by the engine, and is further suitably increased in order to take into account the part of fuel which is in any case led into the by-pass circuit by the adjuster.
- the object of the present invention is achieved by employing a fuel pressurisation system which provides both to pressurise the fuel and to adjust the desired pressure value without using additional external devices, of the type of known pressure adjusters.
- the system according to the present invention consists of the same essential elements already seen in connection with fig. 1 of the known art, i.e.:
- the operation of the proposed system provides that the fuel taken from tank 1 flows through filtering system 2 and arrives at pump-injector assembly 3-4, which is capable of adjusting the pressure to a preset value.
- a bell body 10 is housed, wherein a chamber 11 is formed, where the fuel arrives, within which a contrast spring 12 is housed; said spring rests above against a fixed collar 3b of the fuel supply conduit 3a to pump unit 3, and rests below against the upper surface of a piston 15.
- Said piston has at the same time the function both of intake and supply piston of the fuel coming from conduit 3a, and that of movable anchor, sensitive to the magnetic field generated by an electromagnet.
- reel 13 of said electromagnet is arranged, inwardly closed by a metal sheet 13a and housed in a supporting body 14.
- the wall of said metal sheet 13a builds, together with wall 14a of body 14, a cylinder guiding the displacements of piston 15.
- Piston 15 is hollow and its inner cylindrical chamber in turn builds a guide of the same piston 15 on a cylindrical extension 16 of closing base 17 of body 3.
- a central cavity 18 is formed, which extends into an axial hole 18a in the same base 17; hole 18a puts in communication chamber 18 with end chamber 19 mounting injector unit 4, as better described in the following.
- a non-return valve is housed, consisting of a valve body 20, for example a spherical one, and of a contrast spring 21.
- electromagnet reel 13 When electromagnet reel 13 is electrically energised, it causes the upward (with reference to the drawing) displacement of anchor 15; structure, size and arrangement of spring 12 and valve 20-21, known per se, are such that the upward displacement of anchor 15 determines, in addition to compression of spring 12, the opening of valve 20 and the flow of fuel from chamber 11, i.e. from conduit 3a, to chamber 18.
- valve 20 When piston 15 has reached the upper end stop and stops, spring 21 causes the closure of valve 20. If, at this stage, electromagnet reel 13 is de-energised, the fuel in chamber 18, 18a, 19 - not being able to be released towards the injector (as better explained in the following), nor backwards towards chamber 11 - remains pressurised, under the action of piston 15, pushed by spring 12. The value of this pressure is determined by the ratio between the load of said spring 12 on piston 15 and the useful surface of piston 15.
- Injector unit 4 is directly connected with pump unit 3 by way of the engagement of extension 4a of body 4 into chamber 19, for example by simple screwing in.
- the structure of the injector unit essentially comprises: a first hollow cylindrical body 22, forming a first injector supply chamber 22a; a bell body 23, in whose central chamber a contrast spring 24 is housed; a movable anchor 25, shaped as a cylinder and equipped with an axial boring 25a; an electromagnet reel 26, which partly surrounds the chamber housing spring 24 and partly anchor 25; and a fuel injection nozzle 27, with corresponding closing needle 28, housed in a chamber 29 formed at the bottom of the sliding seat of anchor 25: needle 28 is integral with anchor 25 and is therefore normally closed when electromagnet 26 is not energised and spring 24 pushes anchor 25 downwards.
- chamber 18 of the pump unit is directly and freely in communication with conduit 18a, with chamber 19, with chamber 22a, with the chamber housing spring 24, with conduit 25a and with chamber 29 supplying injector 4. Therefore, when the fuel is pressurised in chamber 18, it is equally so in chamber 29.
- the sizing of the pump unit, in relation to the delivery capability of the injector, is such that, when the engine is operated at high rpm, i.e. when the maximum quantity of supply fuel is required, a pump supply impulse must occur at each opening of the injector.
- phase a) corresponds to piston rise, with reload of spring 15 and simultaneous fuel intake towards chamber 18;
- phase b) is a piston holding phase while waiting to supply the injector with fuel; and
- phase c) corresponds to the fuel injection phase, wherein the fuel is released and the piston is moved downwards.
- the diagram of fig. 5 shows instead the time ratio between the activation signals of electromagnet 13 of the pump and of injector 26, respectively; here it is evident that the pump activation signal is generated immediately after the end of the injector one.
- electromagnet 26 controlling the opening of injector needle 28 is energised and kept energised for the time necessary for the injection of the required fuel amount according to the engine rpm; for all this time, fuel supply is guaranteed by the displacement of piston 15 under the action of spring 12, which extends itself.
- pump unit electromagnet 13 is then energised, which causes piston 15 to rise and spring 12 to reload.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
- The device subject of the present invention falls in the sector of fuel supply systems for internal combustion engines. A large part of internal combustion engines is currently supplied with fuel injection systems which, according to applications, have operating pressures varying between 2 bar and 150 bar. The need arises therefrom to equip the above-mentioned systems with pumps to supply pressurised fuel.
- Depending on the desired pressure level, different types of variously-operated pumps are used. In particular, for pressure levels between 2 and 5 bar, roller rotary electropumps operated by a direct-current motor (as well as go-devil pumps or liquid-ring pumps) are widely used in the technical practice. For higher pressure levels, mechanically-operated alternative pumps are nearly always employed. In this type of systems, by-pass pressure adjusters are normally employed.
- Current anti-pollution regulations impose to adopt ever more advanced fuel-injection systems even in small motorcycle engines. The need to limit costs and to keep such engines efficient requires such systems not only to be functional and to have construction simplicity, but also to consume little power.
- Fig. 1 shows the diagram of a conventional fuel-injection system. The fuel to be processed is drawn from
tank 1 and arrives, through afiltering system 2, atpump 3 which provides to pressurise it and to send it toinjector 4.Injector 4 adjusts the fuel flow, which reaches the engine through the intake manifolds or is directly injected into the combustion chamber. - Supply pressure adjustment is the task, as already mentioned, of a
pressure adjuster 5 which, arranged downstream of the pump, is generally integrated in a by-pass circuit. Pressure adjustment through a by-pass system provides for the pump capacity to be oversize, according to the maximum flow rate required by the injector. In substance, pump capacity is defined according to the value of the flow rate required by the injector upon maximum power delivery by the engine, and is further suitably increased in order to take into account the part of fuel which is in any case led into the by-pass circuit by the adjuster. When, at low engine loads, the flow rate of the fuel to be injected is smaller than the maximum flow rate, the exceeding flow is recirculated through the by-pass; thereby, maximum pump capacity is always processed, but only a part thereof is actually used. Thereby, all the energy imparted to the recirculated part of fuel is lost. The pump will always operate at maximum power causing large energy consumption with low engine loads. - It is an object of the present invention to propose a pump-injector assembly and a supply system for internal combustion engines which overcome the mentioned drawbacks and which are both simpler - and hence cheaper from the point of view of the manufacture thereof - and more easily controllable in their use, so as to achieve pressurisation and adjustment of fuel pressure, as well as being cheaper from an energy point of view. These objects are achieved through the features mentioned in
claims 1 and 7. - In other words, the object of the present invention is achieved by employing a fuel pressurisation system which provides both to pressurise the fuel and to adjust the desired pressure value without using additional external devices, of the type of known pressure adjusters.
- Further features and advantages of the invention are in any case more evident from the following detailed description of a preferred embodiment, given merely by way of a non-limiting example and shown in the accompanying drawings, wherein:
- fig. 1 shows, as already mentioned, a fuel supply system according to the known art;
- fig. 2 shows, in an extremely diagrammatic manner similar to that of fig. 1, a supply system according to the present invention;
- fig. 3 shows an axial section of a possible practical embodiment of the pump-injector assembly according to the invention;
- fig. 4 shows a diagram of the excitation current of the electromagnet operating the supply pump, in a system according to the present invention, as well as the piston displacement diagram of an internal combustion engine supplied by such pump; and
- fig. 5 is a diagram of the synchronisation signals of the supply pump and of the injector, in a system according to the present invention.
- As outlined in fig. 2, the system according to the present invention consists of the same essential elements already seen in connection with fig. 1 of the known art, i.e.:
- · a
tank 1; - · a
filter 2; - · an
electromagnetic pump 3; - · an
injector assembly 4; - The operation of the proposed system provides that the fuel taken from
tank 1 flows throughfiltering system 2 and arrives at pump-injector assembly 3-4, which is capable of adjusting the pressure to a preset value. - This result is possible if a pump is adopted such as the one described for example in patents
EP-0.288.216 in the name of EATON, orEP-0.953.764-B1 in the name of MARELLI; in the known art resulting from these patents, excitation of the operating electromagnet causes displacement of the piston in its fuel intake run, whereas the fuel supply run occurs under the thrust of a pressure spring, which has been loaded during the intake run. - The arrangement is better understandable if reference to the practical embodiment shown in fig. 3 is made, wherefrom it can be appreciated that
pump body 3 andinjector body 4 build a single assembly. - In
body 3, abell body 10 is housed, wherein achamber 11 is formed, where the fuel arrives, within which acontrast spring 12 is housed; said spring rests above against a fixed collar 3b of the fuel supply conduit 3a to pumpunit 3, and rests below against the upper surface of apiston 15. Said piston has at the same time the function both of intake and supply piston of the fuel coming from conduit 3a, and that of movable anchor, sensitive to the magnetic field generated by an electromagnet. As a matter of fact, on the outside ofbody 10 and ofpiston 15,reel 13 of said electromagnet is arranged, inwardly closed by ametal sheet 13a and housed in a supportingbody 14. The wall of saidmetal sheet 13a builds, together withwall 14a ofbody 14, a cylinder guiding the displacements ofpiston 15. - Piston 15 is hollow and its inner cylindrical chamber in turn builds a guide of the
same piston 15 on acylindrical extension 16 ofclosing base 17 ofbody 3. Inextension 16, acentral cavity 18 is formed, which extends into anaxial hole 18a in thesame base 17;hole 18a puts incommunication chamber 18 withend chamber 19mounting injector unit 4, as better described in the following. Inchamber 18, a non-return valve is housed, consisting of avalve body 20, for example a spherical one, and of acontrast spring 21. - When
electromagnet reel 13 is electrically energised, it causes the upward (with reference to the drawing) displacement ofanchor 15; structure, size and arrangement ofspring 12 and valve 20-21, known per se, are such that the upward displacement ofanchor 15 determines, in addition to compression ofspring 12, the opening ofvalve 20 and the flow of fuel fromchamber 11, i.e. from conduit 3a, tochamber 18. - When
piston 15 has reached the upper end stop and stops,spring 21 causes the closure ofvalve 20. If, at this stage,electromagnet reel 13 is de-energised, the fuel inchamber piston 15, pushed byspring 12. The value of this pressure is determined by the ratio between the load of saidspring 12 onpiston 15 and the useful surface ofpiston 15. -
Injector unit 4 is directly connected withpump unit 3 by way of the engagement ofextension 4a ofbody 4 intochamber 19, for example by simple screwing in. - The structure of the injector unit, known per se and hence not described in further detail, essentially comprises: a first hollow
cylindrical body 22, forming a firstinjector supply chamber 22a; a bell body 23, in whose central chamber acontrast spring 24 is housed; amovable anchor 25, shaped as a cylinder and equipped with an axial boring 25a; anelectromagnet reel 26, which partly surrounds thechamber housing spring 24 and partly anchor 25; and afuel injection nozzle 27, withcorresponding closing needle 28, housed in achamber 29 formed at the bottom of the sliding seat of anchor 25:needle 28 is integral withanchor 25 and is therefore normally closed whenelectromagnet 26 is not energised andspring 24 pushesanchor 25 downwards. - According to the present invention,
chamber 18 of the pump unit is directly and freely in communication withconduit 18a, withchamber 19, withchamber 22a, with thechamber housing spring 24, withconduit 25a and withchamber 29 supplyinginjector 4. Therefore, when the fuel is pressurised inchamber 18, it is equally so inchamber 29. - Thanks to this arrangement, it can be appreciated that, according to the main feature of the present invention, an integrated assembly of pump and injector is accomplished, in which, however, the operation of the pump unit can be considered somewhat distinct from injector operation, due to the reasons set forth in the following.
- The sizing of the pump unit, in relation to the delivery capability of the injector, is such that, when the engine is operated at high rpm, i.e. when the maximum quantity of supply fuel is required, a pump supply impulse must occur at each opening of the injector. However, it is not necessary to guarantee the coincidence of the actuation instant of
electromagnet 13 controlling the displacements ofpiston 15, with the actuation instant ofelectromagnet 26 controlling the opening of the injector; but rather, the two actuation instants are preferably alternate, as appears clearly from the diagrams of figs. 4 and 5, shown below. - With such a sizing of the pump unit, it then becomes also possible - when the engine is operated at low rpm, i.e. at idle, and the fuel flow injected by the injector is consequently relatively small - to actuate
electromagnet 13 which controls the displacements ofpiston 15 not following each actuation ofelectromagnet 26 which controls the opening of the injector, but rather following a sequence of an integer number of actuations ofelectromagnet 26, for example every two or three times. As a matter of fact, the full run capacity ofpiston 15 may correspond - at these low rpm - to two or three fuel injections into the engine, and at each fuel fuel-injection,piston 15 will cover only half or a third of its run, to stop as soon asneedle 28 of the injector closes. - In general, if the duration of the fuel injection phase is short and injector capacity is accordingly small, only part of the fuel contained in
chamber 18 will be released and, as a result, in the following intake phase,piston 15 will suck only the fuel amount required to replenishchamber 18. Thereby, flow rate adjustment occurs only according to injector opening time. The energy used during each intake run is constant upon varying of actuation frequency. If frequency decreases, cycle duration increases and, once intake duration has been set, the time in which the magnet is not actuated increases and, as a result, the energy used decreases. This is an obvious great advantage over the known art in which, even at low engine rpm, when fuel demand is low, the pump processes the entire flow even if most of it is bypassed, so that the entire energy employed in such process is wasted. - The diagram of fig. 4 - which refers to the case of engine supply at the highest rpm, and shows the piston position on the y axis and the progress of time on the x axis - shows in the upper half that the displacement of
piston 13 comprises an initial supply phase a), a subsequent holding phase b), and a final return phase c). Phase a) corresponds to piston rise, with reload ofspring 15 and simultaneous fuel intake towardschamber 18; phase b) is a piston holding phase while waiting to supply the injector with fuel; and phase c) corresponds to the fuel injection phase, wherein the fuel is released and the piston is moved downwards. It must here be remembered that holding ofpiston 15 is carried out hydraulically, in the sense that it is determined simply by closure ofinjector needle 28, which prevents the fuel from flowing. The lower half of the diagram of fig. 4, to be compared directly with the upper half thereof, shows the development of the excitation current (value on the y axis) over time (value on the x axis); here it shows clearly that the excitation current increases dramatically during phase a) which controls and displaces the piston, then drops to zero in phase b) which holds the pressure of the piston, and in phase c) when the injector control is activated. - The diagram of fig. 5 shows instead the time ratio between the activation signals of
electromagnet 13 of the pump and ofinjector 26, respectively; here it is evident that the pump activation signal is generated immediately after the end of the injector one. In other words,electromagnet 26 controlling the opening ofinjector needle 28 is energised and kept energised for the time necessary for the injection of the required fuel amount according to the engine rpm; for all this time, fuel supply is guaranteed by the displacement ofpiston 15 under the action ofspring 12, which extends itself. Following de-energising ofelectromagnet 26,pump unit electromagnet 13 is then energised, which causespiston 15 to rise andspring 12 to reload. - By the described structure of the pump-injector assembly according to the present invention, various advantages are hence obtained, which may be summed up in the following:
- the use of a pressure adjuster is abandoned. By opening electrically-controlled
injector 27, the fuel is pumped thanks to the extension ofspring 12, which provides to automatically keep the pressure at the desired value; this value, determined according to the preload assigned to the spring, remains virtually constant, given the modest variability of the spring load during extension thereof; - the injector supply phase can be completed in a very short time because the energy required is already available and stored in the previously loaded spring. Since the spring can be reloaded between an injection phase and the other, it is therefore not necessary to keep to the characteristic movement times of
electromagnet 13; - the electric power installed to activate
electromagnet 13 can be remarkably lower because the work required for displacingpiston 15 and for compressingspring 12 can be produced over a longer time, i.e. precisely in the time between an injection phase and the other; - considerable energy savings are made, due to the following factors: the fact that the pump must not treat excess fuel (i.e. the one normally recycled from the pressure adjuster of the prior art); the fact that a single run of
pump piston 15 can be used, at low engine rpm, for multiple injector supplies; and the fact that, at intermediate rpm, the supply run ofpiston 15 is limited andspring 12 does not extend completely, hence the intake run is also limited to the one strictly necessary for the partial reload ofspring 12; - further energy savings are obtained, due to the fact that no power consumption exists in phase b) of holding of the cycle time, the holding being guaranteed hydraulically by the temporary closure of the injector.
- it is further possible to simplify the control algorithm in the electronic control unit, since the injector closure signal can be used as a control signal for the activation of
electromagnet 13, simplifying the synchronisation between pump and injector; - reduced cost of the system, due to the reduction of the components (doing without the pressure adjuster) and to the greater construction simplicity (integrated pump-injector assembly);
- It is understood, however, that the invention is not to be considered limited to the particular arrangement illustrated above, which represents only an exemplary embodiment thereof, but that different variants are possible, all within the reach of a person skilled in the field, without departing from the scope of protection of the present invention, as defined in the following claims.
Claims (15)
- System for the supply of fuel-injection, internal combustion engines, of the type comprising a pump unit (3) cooperating with an injector unit (4), the pump unit comprising a piston-cylinder assembly (15; 13a-14a), an electromagnet (13) exercising its force of attraction on a movable anchor (15), consisting of the piston or integral therewith, a spring (12) acting on the anchor or piston (15) with an elastic force of a sign opposite to that of the force of attraction of the electromagnet, the run of said anchor-piston upon electromagnet actuation being used to load said spring (12) during the fuel intake phase,
characterised in that the supply run of the piston (15) is driven by the elastic energy stored in said spring (12),
that said supply run pressurises the fuel so as to supply it directly to the injector unit (4), and
in that fuel injection start is driven only by the opening of the injector unit needle (28). - System for the supply of fuel-injection, internal combustion engines as in claim 1), characterised in that adjustment of the injector supply pressure is determined by the ratio between the load of said spring (12) and the useful surface of the piston (15).
- System for the supply of fuel-injection, internal combustion engines as in claim 1) or 2), characterised in that the closure signal of the injector needle (28) is used, in an electronic control unit, as a signal activating the pump unit (3).
- System for the supply of fuel-injection, internal combustion engines as in any one of the preceding claims, characterised in that, at the maximum engine rpm, said electronic control unit sends a signal activating the electromagnet (13) of the pump unit (3) following each deactivation signal of the electromagnet (26) of the injector unit (4).
- System for the supply of fuel-injection, internal combustion engines as in any one of claims 1) to 3), characterised in that, at the minimum engine rpm, said electronic control unit sends a signal activating the electromagnet (13) of the pump unit (3) following a multiple integer of deactivation signals of the electromagnet (26) of the injector unit (4).
- System for the supply of fuel-injection, internal combustion engines as in any one of the preceding claims, characterised in that between said pump unit (3) and a fuel tank (1), there is a filter (2) only.
- Pump-injector assembly, for the supply of internal combustion engines, of the type comprising a pump unit (3) equipped with a cylinder-piston assembly (15; 13a-14a), an electromagnet (13) exercising its force of attraction on a movable anchor (15), against the action of a contrast spring (12), the run of said anchor (15), upon excitation of said electromagnet (13), being used for the intake of fuel into a fuel chamber (18) formed in the pump unit (3),
characterised in that an injector unit (4) is directly associated with said pump unit (3),
in that said movable anchor consists of - or is integral with - a fuel supply piston (15),
in that said fuel chamber (18) of the pump unit (3) is closed upstream by a non-return valve (20) and is in direct communication, downstream, with a supply chamber (29) formed in said injector unit (4),
in that the fuel in said fuel chamber (18) and in said supply chamber (29) is kept pressurised by the action of the piston (15) of the pump unit, under the thrust of said contrast spring (12), and
in that an electromagnetically-operated needle (28) is associated with the injector, the opening of said needle controlling the supply run of said piston (15) of the pump unit. - Pump-injector assembly for the supply of fuel-injection, internal combustion engines as in claim 7), characterised in that said non-return valve (20) is placed between said fuel chamber (18) and a cylinder chamber (11), wherein said contrast spring (12) is housed, said chamber being directly connected with a fuel tank (1).
- Pump-injector assembly for the supply of fuel-injection, internal combustion engines as claimed in claim 7), characterised in that said piston (15) is hollow and is guided on the outside within a cylinder consisting at least in part of the wall (13a) of the electromagnet reel (13).
- Pump-injector assembly for the supply of fuel-injection, internal combustion engines as claimed in claim 9), characterised in that the electromagnet reel (13), closed on the inside by a metal sheet forming said wall (13a), is housed in a support body (14), the base of which forms a further cylindrical wall (14a) guiding the movements of piston (15).
- Pump-injector assembly, for the supply of fuel-injection, internal combustion engines as claimed in claim 9), characterised in that said piston (15) is further guided, on the inside, along a cylindrical appendix (16) of a base (17) closing the pump unit body (3).
- Pump-injector assembly, for the supply of fuel-injection, internal combustion engines as claimed in claim 7) or 11), characterised in that said fuel chamber (18) of the pump unit is formed in said appendix (16) guiding the piston (15), in said chamber being housed said non-return valve (20) and a respective pressure spring (21), the seat of said non-return valve (20) being formed in the piston head.
- Pump-injector assembly for the supply of fuel-injection, internal combustion engines as claimed in claim 12), characterised in that said fuel chamber (18), formed in said extension (16), extends into an axial hole (18a) of the base (17) of the pump unit, which puts said chamber (18) in communication with an end chamber (19) mounting the injector unit (4).
- Pump-injector assembly for the supply of fuel-injection, internal combustion engines as claimed in claim 7) or 13), characterised in that said injector unit (4) is directly connected with the pump unit (3) by the engagement of an extension (4a) of the same with said end chamber (19), preferably by simple screwing.
- Pump-injector assembly, for the supply of fuel-injection, internal combustion engines as claimed in claim 7) or 13), wherein said injector unit (4) comprises a movable anchor (25), actuated by an electromagnet (26) against the action of a contrast spring (24) and which anchor moves a needle (28) closing a fuel injection nozzle (27), as well as a fuel supply chamber (29), characterised in that said supply chamber (29) is in direct, continuous communication with said fuel chamber (18) formed in the pump unit (3) by means of respective through-passages (22a, 25a).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMI20050688 ITMI20050688A1 (en) | 2005-04-18 | 2005-04-18 | FUEL SUPPLY SYSTEM FOR INTERNAL COMBUSTION ENGINES AND PUMP-INJECTOR UNIT WITH ELECTROMAGNETIC DRIVE USED IN SUCH A SYSTEM |
Publications (3)
Publication Number | Publication Date |
---|---|
EP1717439A1 true EP1717439A1 (en) | 2006-11-02 |
EP1717439B1 EP1717439B1 (en) | 2008-01-09 |
EP1717439B9 EP1717439B9 (en) | 2008-12-03 |
Family
ID=35809617
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20060112490 Expired - Fee Related EP1717439B9 (en) | 2005-04-18 | 2006-04-11 | Fuel injection system for internal combustion engines |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1717439B9 (en) |
DE (1) | DE602006000410T2 (en) |
IT (1) | ITMI20050688A1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0288216A1 (en) * | 1987-04-15 | 1988-10-26 | Eaton S.A.M. | Electrical fluid pump |
WO1994018449A1 (en) * | 1993-02-01 | 1994-08-18 | Sampower Oy | Method and apparatus for controlling the injection of fuel |
EP0953764A1 (en) * | 1998-04-27 | 1999-11-03 | MAGNETI MARELLI S.p.A. | Volumetric pump |
US20030047625A1 (en) * | 2000-03-10 | 2003-03-13 | Paul Tinwell | Fuel injector |
-
2005
- 2005-04-18 IT ITMI20050688 patent/ITMI20050688A1/en unknown
-
2006
- 2006-04-11 DE DE200660000410 patent/DE602006000410T2/en active Active
- 2006-04-11 EP EP20060112490 patent/EP1717439B9/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0288216A1 (en) * | 1987-04-15 | 1988-10-26 | Eaton S.A.M. | Electrical fluid pump |
WO1994018449A1 (en) * | 1993-02-01 | 1994-08-18 | Sampower Oy | Method and apparatus for controlling the injection of fuel |
EP0953764A1 (en) * | 1998-04-27 | 1999-11-03 | MAGNETI MARELLI S.p.A. | Volumetric pump |
US20030047625A1 (en) * | 2000-03-10 | 2003-03-13 | Paul Tinwell | Fuel injector |
Also Published As
Publication number | Publication date |
---|---|
EP1717439B1 (en) | 2008-01-09 |
ITMI20050688A1 (en) | 2006-10-19 |
DE602006000410T2 (en) | 2009-01-08 |
DE602006000410D1 (en) | 2008-02-21 |
EP1717439B9 (en) | 2008-12-03 |
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