Claims:We Claim

1. A fuel injector (10) with an integrated pressure amplification module (12), said fuel injector (10) comprising:
an injector body (14); characterized in that
said pressure amplification module (12) integrated with said injector body (14), said pressure amplification module (12) adapted to pressurize fuel before delivering pressurized fuel through said injector body (14).

2. The fuel injector (10) in accordance with Claim 1 wherein said pressure amplification module (12) comprises an end cap (13) and a pressure amplifier piston (17) positioned proximate to said end cap (13) and guided via clearances (15A, 15B).

3. The fuel injector (10) in accordance with Claim 2 wherein said end cap 13 comprises a bar filter (21).

4. The fuel injector (10) in accordance with Claim 2 wherein said pressure amplifier piston (17) comprises a unidirectional valve (20) adapted to pressurize fuel present in a chamber (19) that is proximate said amplifier piston (17) for fuel delivery from said fuel injector (10).

5. The fuel injector (10) in accordance with Claim 4 wherein said pressure amplification module (12) comprises a first spring member (16) that is positioned between said amplifier piston (17) and a portion of said injector body (14).

6. The fuel injector (10) in accordance with Claim 4 wherein said pressure amplifer piston (17) comprises a unidirectional valve (20) which facilitates fuel to flow from said end cap (13) to said chamber (19) via an orifice (27).

7. The fuel injector (10) in accordance with Claim 6 wherein said pressure amplifer piston (17) comprises a ball (22) positioned against said orifice (27) of said unidirectional valve (20), said ball (22) prevents fuel present in said chamber (19) from flowing to said end cap (13) via said orifice (27).

8. The fuel injector (10) in accordance with Claim 7 wherein said pressure amplifier piston (17) comprises a second spring member (24) positioned between said ball (22) and said amplifier piston (17), said second spring member (24) adapted to be compressed by said ball (22) to facilitate channeling fuel from said end cap (13) to said chamber (19) via said orifice (27).

9. The fuel injector (10) in accordance with Claim 2 further comprising a sealing ring (26) positioned between said amplifier piston (17) and said end cap (13), said sealing ring (26) facilitates sealing between said injector body (14) and said end cap (13).
, Description:Field of the invention
[0001] This invention relates to a fuel injector and more particularly to a fuel injector with an integrated pressure amplification module.

Background of the invention
[0002] US 2004/0025843 A1 describes a fuel injection system for internal combustion engines. A fuel injector with a pressure amplification module is proposed which uses amplifier piston arrangement to amplify the fuel pressure at the injector end. The amplifier piston separates the pump side and the injector side and is having a bigger area on the side where high pressure fuel from the pump side acts and a smaller area on the injector side. The ratio of area of amplifier piston on the pump side and the injector side decides the ratio of pressure amplification theoretically.

Brief description of the accompanying drawings
[0003] Figure 1 illustrates a schematic diagram of a fuel injector.
[0004] Figure 2 illustrates a schematic diagram of a pressure amplification module integrated with the fuel injector.

Detailed description of the invention
[0005] Figure 1 illustrates a fuel injector 10. The fuel injector 10 comprises an injector body 14. A pressure amplification module 12 is integrated with the injector body 14, the pressure amplification module 12 adapted to amplify fuel pressure before delivering pressurized fuel through the injector body 14.
[0006] The fuel injector 10 comprises an injector body 14. A pressure amplification module 12 is integrated with the injector body 14 and forms an integral portion of the fuel injector 10. A bar filter 21 is coupled to the pressure amplification module 12 and filters fuel that flows through the pressure amplification module 12. In an embodiment, the end cap 13 comprises a bar filter 21. The pressure amplification module 12 forms an integral portion of the injector body 14 such that the pressure amplification module 12 and the injector body 14 constitute a unitary assembly. In an alternate exemplary embodiment, the pressure amplification module 12 may be removably coupled to the injector body 14.
[0007] Figure 2 illustrates a pressure amplification module 12 integrated in the fuel injector 10. The pressure amplification module 12 comprises an end cap 13 and a pressure amplifier piston 17 positioned proximate to said end cap 13 and guided via clearances 15A, 15B. A bar filter 21 is defined in the end cap 13. The bar filter 21 comprises a first fuel flow path 23 and a second fuel flow path 25 that are separated by a filtering element. The filtering element separates the fuel that flows from the first fuel flow path 23 to the second fuel flow path 25. A sealing ring 26 is positioned between the end cap 13 and the injector body 14. The sealing ring 26 facilitates maintaining sealing contact between the end cap 13 and the injector body 14, and also acts as a stopper for a pressure amplifier piston 17. More specifically, the sealing ring 26 is positioned between the end cap 13 and the pressure amplifier piston 17 and prevents the pressure amplifier piston 17 from contacting the end cap 13. The sealing ring 26 facilitates sealing between the injector body 14 and the end cap 13.
[0008] The pressure amplifier piston 17 is positioned below the sealing ring 26. The pressure amplifier piston 17 is inserted within the injector body 14 and is guided via clearances 15A and 15B with a very close tolerance. A first spring member 16 is positioned between a bottom portion 18 of the amplifier piston 17 and a portion of the injector body 14. The pressure amplification module 12 comprises a first spring member 16 that is positioned between said amplifier piston 17 and a portion of said injector body 14.
[0009] The pressure amplifier piston 17 comprises a unidirectional valve 20 adapted to pressurize fuel present in a chamber 19 that is proximate the amplifier piston 17 for fuel delivery from the fuel injector 10. The unidirectional valve 20 which facilitates fuel to flow from the end cap 13 to the chamber 19 via an orifice 27. The unidirectional valve 20 is positioned within the amplifier piston 17. The pressure amplifer piston 17 comprises a ball 22 positioned against the orifice 27 of the unidirectional valve 20, the ball 22 prevents fuel present in the chamber 19 from flowing to the end cap 13 via the orifice 27. Additionally, the ball 22 is positioned below the unidirectional valve 20 such that the ball 22 rests against a valve seat of the unidirectional valve 20 and closes an orifice 27 of the unidirectional valve 20. The ball 22 is held on to the valve seat with a spring force provided by spring 24 thus closing the orifice 27 located in the unidirectional valve 20. The pressure amplifier piston 17 comprises a second spring member 24 positioned between the ball 22 and the amplifier piston 17, the second spring member 24 adapted to be compressed by the ball 22 to facilitate channeling fuel from the end cap 13 to the chamber 19 via the orifice 27.
[0010] A working of the fuel injector 10 with integrated pressure amplification module 12 is described as an example. When pressurized fuel from a fuel pump (not shown) enters the fuel injector 10 and flows from the first fuel flow path 23 to the second fuel flow path 25, the bar filter 21 facilitates separating impurities from the fuel. Pressurized fuel from the bar filter 21 acts on the amplifier piston 17 and causes the amplifier piston 17 to translate in the downward direction against the spring force generated by the spring 16. When the amplifier piston 17 is translated in the downward direction, the first spring member 16 is compressed. The translation of the amplifier piston 17 in the downward direction causes fuel that is present in the chamber 19 to get compressed and delivered out of the fuel injector 10.
[0011] In the downward stroke of the amplifier piston 17, lower pressure fuel from bar filter 21 enters through the orifice 27 and acts on a small area of the ball 22 and this results in a smaller force. Whereas high pressure fuel acts on a bottom portion of the ball 22 which results in a higher force by the ball 22 on the valve seat. Hence the ball 22 is held tight against the valve seat of the unidirectional valve 20 thus preventing fuel that enters from the bar filter 21 from entering the chamber 19 via the orifice 27.
[0012] After completion of the downward stroke of the amplifier piston 17, the amplifier piston 17 retracts due to the spring force from the spring 16. As the amplifier piston 17 retracts, fuel pressure in the chamber 19 reduces due to increased volume in the chamber 19. On the other side of the amplifier piston 17, the volume reduces thus compressing the fuel in the bar filter 23. Due to higher pressure on the other side of the amplifier piston 17, the ball 22 is moved against the spring force of the spring 24, thus allowing fuel to flow from the bar filter 23 to the chamber 19. Thus the chamber 19 gets replenished with fuel and makes it ready for the next stroke.
[0013] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to leverage and dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.