Title of Invention

FUEL INJECTOR

Abstract

The invention relates to 09.5mm injector family having a nozzle which is not an integral part of nozzle holder such that nozzle can be replace in the event of any damage to nozzle instead of discarding the whole injector, the practice followed in prior art. The injector has a nozzle body having a asymmetrical pressure chamber on only one said of the nozzle axis, a needle with its axis offset from the nozzle body which arrangements provide sufficient wall thickness against the high pressure, the surfaces of nozzle and nozzle holder butt each other, the nozzle held onto the nozzle holder by means of a retaining nut with a predetermined torque. The said needle controlled by means of a pressure spring compressible by a pressure adjusting screw to maintain for transferring force from the said pressure spring onto the needle. The lapped surface and tightening torque a leak proof, safe, efficient injector assembly with a replaceable nozzle.

Full Text

TECKnCAL FZBLO OF IWBVTIOV The present iixvention is a Diesel Fudl Injector for direct iiijection application of an internal combustion diesel engine. The function of this injector is to inject diesel fuel into the combustian chamber of diesel engjbie in automiaed form. There are different standard sizes of injectors used on diesel engpmes, namely : 09.5mm» 017nun» 02 Itnm, 025mm etc. *31ender Injector* belongs to the 09.5mm Injector family. PRIOR ART The existing Injectors in 09.5 Iigector family have Noezte as integral part of Nozzle Holder. Hie construction features of existing h^ectors designs in the 09.5 Injector family, restricts the control over length of Nozzle Needle and hence have longer Needle length (up to lOQmm). These features are likely to have the following disadvantages. 1. Since the Hcsss^ is integral part of Nocs^ Holder^ any damage to Nozzle leads to replacement of Injectcn: as a whole 2. Since the Needle length is more» it becomes difficult to maintain the required tol^ances during manufacturing 3. Incorporating the features of Nozde with apray hol^i in seat^ in these Injectors aJSect the spray symmetiy because of longer Needle length and hence the emissions 4. Some of the Injectors involve brafidng and crimping of components in higpti pressure fuel passage area. This makes the manufacturing process critical and may have leakage probl^ns at higher pressure OBJECT OF THE IHVBHTIOV The object of the invention is to overcome the disadvantages of prior art and to provide an injector (in 09.5 Injector family) with a replaceable nozzie. The other additional objectives are to provide an Ixgector with improved performance, manufacturabiitty and serviceability compared to the existix:^; Injectors in the 09.5 Injector £amily. A robust design with improved perfonnance^ manufacturabitity and serviceability, is achieved hy the following design features in the injector as per the invention:- 1. Nozzle is replaceable and serviceable. 2. Features of Nozzle with Spray Holes in Seat €a:e incorporated. 3. Needle length is reduced so that the advantages due to shorter needle length can be realized. 4. Some ofthe critical manufacturingprocesses are avoided Some of the Injectors in the 09,5 Injector family have Notaasle as an integral part of Nozzle Holder, in which case any damago to the Nozzle leads to discarding of Injector as a whole. But the art as per the invention has a replaceable Noz2de> Some of the manufacturing processes like crimping, brazing of the components of Injector especially in the hi^ pressure fuel passi^^, which may lead to leakage problems and make the manufiscturing process critical, have been eliminated. The Needle length in the art as per the invention has been reduced to approx. 3Qmm. Shorter Needle length provides lot of advantages in manufacturing and functionality. DEBCRZPTIOV OF THE OVEVTIOV WITR RimiBVCB TO TBB ACCOMPAHYniO DRAWmOS:- The invention is described with the aid of the follawing acccmipanyii^ drawings-- Fig 1 illustrates the injector as per the invention with short needle. Fig 2A illustrates features of Nozzte with spray holes in seat, generally known to be used in an injector. Fig 2B illustrates detailed features of Nozzle with spray holes in seat. Fig 2 illustrates features of xhozsde as adapted in the injector as per the invention. Reference numerals made in the parts of the drasoings of Fig 1 to 3 has been described below :- DBTJULED DSftCRIFTXOV 09 THE nrVXlTTIOV : Now the invention will be described in detail along with reference to the drawings for ea^^ understanding. According to the inveotioii, the Slander Injector (Ref. Figure no.l)» consists of an izilet connection stud-(4)» through which the high pressure tiel from fuel pump (not ahowrO enters the injector. The fiiel while flowing through the inlet connection stud-(4)> gets filtered by a Bar-fiater-(19). The bar filter-(19), consista of flutes. A small clearance created between the inlet connection stud bore and flute surface of bar-filter enables fiiel filtration. Position no, 15 is sealing washer which provides a leak proof joint at hi^ pressure between the inlet connection stud -(4) and ti» no2sde holder body-(1). The inlet connm^tion stud-(4) is fastened on to the nossdie holder-(l) and tightened to a specified torque with sealing washer-(l^ in between* The sealing washer-(15) has a low hardness value compared to the No2ssle Holder Body-(l) and the Inlet Connection Stud-(4). BecauMe oftbs tightening torque of the Inlet Connection Stud-(4) and specified surface finish and flatness maintained on both the surfaces of Sealing washer-(l^ as well as on the siuiaces of Nozzle Holder Body-(l) and Inlet Connection Stud-(4) butting the Sealing Washer-( 15)» a leak proof joint against high pressure is achieved. After getting filtered in the Inlet Connection Stud-(4), the hi^ pressure fiiel Hien enters the Inlet Hole->(20) of Nozzle Holder Body-(l). Hie Inlet Ho]e-(20) of Nozde Holder Body-(l) opens in to the Inlet Hole-(2i) of Nozzle body-(18). The Inlet Hole-(20) of Nozsde Holder Body-(l) and Inlet Hole-(21) of N but also take care of positioning assembly of Nozzle body-(18) and Nossde Needle-(17) with respect to Nozzle Holder Body reference. Prom the Inlet Hole-(21) of Nozzle body-(18), the high preOTure fuel then entc»rs the Reaaure Chainber-(22) of Nozs^ body-^18). The Preaaure Chflmber-(22) is asymmetric, which meana, the Preaaure Chember ia on only one aide of the axis in the Nossle body-(18). The NosszLe Needle (17) bore ia alao offaet with reapect to the Nozde Body (18) axis. Both theae arrangiementa provide aii£ELcient wall thickneaa againat high preaaure at all the critical re^ona. The high preaaure fuel accumulatea in the Preaaure Chamber-(22) and in the annular apace between Noz;^ Needle-( 17) and the Nozzle Needle guide bore below the Preaaure Chamber-(22). Ihe Nozzle Needle-(17) ia held in cloaed poaition by the Spring-(7) with aome definite force which definea the openii^ preaaure (the preaaure est which fuel atarta apraying out of h^ector) of Injector. Once the ftiel preaaure reachea a preaaure equal to the Opening Preaaure, then the Nozzle Needle*(17) opena and the fuel ia aprayed out throu^ the apray holea (not ahown in the figure) provided at the tip of the Nozzle Body-(18). The Spring force from the Spr]ng-(7) ia transferred to the HozsAe Needle-(17) through the Puah Rod-(3). The Puah Rod-(3) also trana£sra the Nozzle Needle-(17) mov^nent to the Spring-(7). Poaition No.6 ia Pre^ure Bok^ which acta aa aeat for the Spring-(7) and alao guides the Spring movement. The movement of Nozzle Needle-( 17) from the Push Rod-(3) is picked up by Pressure Bolt-(6) and then transferred to the apring-(7), Position No. 11 is Opening Pressure adjusting Screvir. By loosening or tie^temr^ the Opening Pressure Adjusting SGreiKr-(l 1)» the Sprixkgr{7) can be compressed to dLBTerent extent, which in turn determines the Opening Pressure of Injector* Once the required Opening Pressure is adjusted, the Opening Pressure Adjusting Screwr-11 is locked by the Opening Pressure Adjusting Screw Lock Nut-(9). The fuel that gpts leaked oCT through the clearance in Nozzle Needle guide*(2d) portion passes through the bore provided for Push Rod-(3) and enters the bore where 8pring-(7) is placed. From here this goes back to the leak off circuit of the engine through the Leak Off Baxt}o-(12). The Leak Off Banjo-(12) is fastened to the Noz^e Holder-(l) by a Leak Off Banjo Bolt-^IS)* The Sealing Washers-(10} above and below the Leak Off Banjo-(12) prevent the leakage. Hie Leak Off Banjo Bolt-( 13) is t^tenad to a siMoifi.ed torque so that a leak proof joint is obtained, A flat provided on leak off Banjo Bolt creates room for leak off fiiel to pass through and enter the Leak Off Banjo- (12). The surfaces of both - No2sde Body-(18) and NQ2SEde Holder^ 1} which butt each other, have required surfiace finish and flatrsess maintained on them. The Nozzle is tightened on to the No^sle Holder-(l) using Nt^ssle Retaining Nut-(2) with a specified torque. This torque is calculated considering the maximum fixe! pcreasure in the Injector. Siurfiace finish, flatnesa on the surface and tightening torque altogether enaiire a leak proof joint in the assembly of Vixzzie and Nozzle Holder. The Injector is mounted on engine cylinder head (not showD^ using a clamp or claw (not ahovtm). Sealing washer-(16) and Carbon Dam-(14) provide the required seal so that the combustion gases do not enter the clearance between the Injectm* and Inj The injector as per the invention has thus a replaceable xuoaEde, a short needle, an asymmetrical pressxire chamber and features ctf nozzle with spray holes in seat. The construction of the invention as per the invention is described below:- In the injector as per the invention essentially' Noz^ is not an integral part of Nozsde Holder. No2sde(18) is replaceable and serviceable in the injector as per the invention. Hie replaceable nozzSe is fitted by means of a JHozzie Retaxcdng Nut(2}. Ihe Nozde is positioned firstly by the Dowel Ptos and then firmly held by t^tening the Nozsle Retaining Nut(2) to a specified torque. The sur£aces(25) of both the Nozsle(18) and Nozzle Hold^l) which butt each other are lapped to maintain the required flatness on the surfaces. llien the JXosszh is listened onto the NofisiSe Holder using the Nozzie Retaining Niit(2) with a specified torque. The torque is predetermined in relation to tnayimutn fuel pressure in the injector. The lapped surfiaces and the ti^rhtening torque together ensure a leak proof joint in the assembly of No2zle( 18) axtA Nozzle Hold6r( 1). Some of the Injectors in the 09.5 Injector £uaily> have a desigp:! feature which restricts the control over the length of the Ifeedle and hence ham a longer Needle lei^^. The hi^ctor as per the invention has shorter Needle lei^;th. Prom the Injector function point of view, it is important to maintain a specified run out of Needle ^at with respect to Needle Quide. As the Needle length reduces, it becomes more easy to maintain this run out during production. Shorter Needle length enables tbo easy introduction of the foature -Nozzle with Spray Holes in Seat. No2!i:de with Spray Holes in Seat is well known for low HC emission; in this No2sde (R^. Fig.2B)y the Spray Holes(24) are in the seat and closed by the Needle. This feature has a great adtrante^e with respect to Hydro Carbon emissions, since the needle(l7) closes the spray holes(24) thereby preventing the fiiel accumulated below the Needle from getting evaporated and being thrown out in the exhaust as Hydro Carbon emissions. Also the HozsAe has negligible sac volume(26). As described above, the object of achieving an Injector with a replaceable Noszle has been achieved in whi(^ attempts have been made to obtain an improved performance, manufacturability and serviceability. In the preceding paras, even though the descriptions have heen made with reference to preferred and exemplary embodim^mts of the invention, other modifications and variations of invention obvious to those skilled in the art, aU fall within the true spirit and scope of the invention. WE CLAIM 1. A Diesel fiiel injector (ia 09.5 Ii^j^tor ftuaily) with replaceable nozzLe, a short needle and an asyxmnetrical chamber feature comprising : - a NosszLe Body (18) having a pressure chamber(22) on only one side of nozzle axis, - a Needle (17) having its cuds offset from the nozzle body (18) axis, - a retaining nut (2) for holding the nozzle onto the nozzle holder( 1) by applying a predefined torque, - a pressure sprir^ (7) seated onto a pressure bolt (6) to keep the needle (17), in closed condition and maintain the required openizig pressure of injector - a push rod (3) interposed for transferring force from the pressure spring (7) onto the needle (17)^ - a Opening Pressure Adjusting Scre^ll) to compress the pressure spring^7), along with - a Opening Pressure Adjusting Screw lock nut(9)» - wherein the surfaces of the nozzle(18) and the nozzle holder(l) butt each other, - wherein when Opening Aressuire Adjusting Screw(l 1) is loosened or tightened, the spring (7) is compressed according^. - wherein the Opezting PreaaurB Adjustiog Screw (11) is lockable by a - wherein high pressure &iel enters the pressure chaxnber (22) > - wherein high pressure fuel accumulates in pressure - wherein needle (17) is held in closed position 1^ spring (7) ujitil pressure is less than opening pressure and in open position by spring (7) when pressure is equal or greater than opening pressure via the push rod(3) such that the pressure spring force from spring(7) is transferred onto nozzle needle (17), and - wherein movement of nozzle needle (17) from push rod(^ is taken up by pressure bolt(6) and thereafter transferred back to spring(7). 2. A Diesel Fuel Ijqjector as claimed in daim-1 in 09.5mm detachable injector nozziiei held by a nozzfe retaining nut with a predetermined axial force obtained by tightening nosszie retaining nut to a predefined torque. 3. A Diesel Fuel Injector as daimed in claim-1» has nozzle having pressiire chamber on only one side of nozzte axis and needle axis d&et frtmi no2zie body axis in the nozzle assembly so has to obtain the necessaxy safe wall thickness against high pressure. 4. A Diesel Fuel iqjector as claimed in claim-1, wherein a push rod transfers the spring force to the nozzle needle and needle movement back to spring. 5. A Diesel Fuel injector as claimed in claim-1, as described in the complete specification and as illustrated in the accompanying dra«nng».

Documents:

809-che-2003-abstract.pdf

809-che-2003-claims duplicate.pdf

809-che-2003-claims original.pdf

809-che-2003-correspondence others.pdf

809-che-2003-correspondence po.pdf

809-che-2003-description complete duplicate.pdf

809-che-2003-description complete original.pdf

809-che-2003-description provisional.pdf

809-che-2003-drawings.pdf

809-che-2003-form 1.pdf

809-che-2003-form 19.pdf

809-che-2003-form 26.pdf

809-che-2003-form 3.pdf

809-che-2003-form 5.pdf