Indian Patents. 268549:INJECTOR OF A FUEL-INJECTION-SYSTEM OF AN INTERNAL COMBUSTION ENGINE (IC-ENGINE)

Title of Invention	INJECTOR OF A FUEL-INJECTION-SYSTEM OF AN INTERNAL COMBUSTION ENGINE (IC-ENGINE)
Abstract	An injector with a double switching control valve is proposed, where a valve body 45 is guided in the housing of the control valve, so that the wear and tear on a valve cone 47 of the valve body 45 and a first valve seating 43 in the housing of the control valve 15 is reduced. (Figure 2).

Full Text	Injector of a Fuel-Iniection-Svstem of an Internal Combustion Engine (IC-Engine) State of the art of technology The invention relates to an injector for an IC-engine with a control valve to open and to close a nozzle pin, where the control valve has a valve body with a valve cone, which acts in conjunction with a valve seating of a housing of the control valve. In this injector, the valve body is pressed against a plunger of an actuator by a locking/closing spring and is centered over the valve seating. The invention-based injector for an IC-engine with a control valve for the opening and closing of a nozzle pin where the control valve includes a housing and an actuator where a graduated drilling with a spring space for the seating of a valve body is formed in the housing where a section of the cascade/graduated drilling is formed as inlet and a section of the graduated drilling as outlet, and with a first valve seating, where the valve body has a valve cone which is co-acting with the first valve seating and where the valve body is pressed by a locking spring arranged in the spring space against the piston of an actuator, it is visualized that the valve body is inserted/guided in at least one section of the graduated drilling, and where there are one or several passages for the control-quantity of the injector in this section.. Advantages of the invention Since the valve body is guided in at least a section of the graduated drilling, it is ensured, that the valve cone of the valve body almost always meets the housing in the center with minimum slippage. Thereby, first the local overloading of the valve cone and the valve seating is avoided, and the wear of the valve seating and valve cone is reduced. Both effects lead to the fact, that there is only a small alteration of the valve lift or stroke, during the running of the IC-engine with the result that the operating behavior of the IC-engine remains almost constant during the complete life-cycle. In this context, the size of the play (space) between the graduated drilling and the guide section of the valve body has to be chosen so large, that the valve body in the closing position of the control valve centers itself to the valve seating of the housing, for, only then the control valve gets tightly closed. Advantageous variants of the invention-based injector that provide for one inlet of the control valve remains in contact with one control space of the injector, whereas one outlet of the control valve remains in contact with a reverse flow of the fuel. In a further advantageous design of the invention it is planned, that the locking spring acts on the valve body transverse to the direction of operation of the actuator. Thereby it is guaranteed that the valve body always takes a defined position and that the control valve is closed under an actuator switched on without current. Thereby it is provenly advantageous, if the closing spring supports itself at least indirectly against the housing and a spring-plate of the valve element. The guiding of the valve body can be done preferably in the area of the outlet and/or in the area of the spring area/space. Thereby it is alternatively possible that the valve body is guided at the spring-plate or that in the spring area a sleeve (casing) is provided and that the valve body is guided from the sleeve. In order that the control quantity can flow through the invention-based control valve despite the insertion of the valve body in the housing, the passages are formed or designed alternatively as grooves or flattenings and/or longitudinal bores/drills running longitudinal to the valve body. Thereby the flow-resistance of the control valve in open position can be reduced to such an extent, that the functioning of the injector is not negatively affected by guiding the valve body in the graduated drilling. In order to simplify the production and assembly, the housing can be designed in two parts. In this context, the control valve can be a separate component as also one that is integrated in the injector. In the latter case, the housing of the control valve is at the same time the housing of the injector. Advantageously the control valve can be designed as 2/3-way-control valve. Thereby multiple injections can be realized more easily; there are further possibilities to shape or form the course of injection. In order to take optimum advantage of the invention-based injector with the invention-based control valve, the valve body can be activated with a Piezo-actuator. Extremely fast control movements are thereby possible. As a result of the design/form of the invention-based control valve, the seating in the housing and the valve cone on the valve body barely wears out, and therefore the functioning of the control valve during the complete life-cycle of the IC-engine is assured. The invention-based injector is preferred for use in Common-Rail fuel-injection-systems. Further advantages and ideal design forms can be seen from the following drawing, its description and the Patent Claims. All distinguishing characteristics/parameters described in the drawing, its description and the Patent Claims can be significant for the invention either individually or in optional combination with one another. Drawings Following are illustrated: Figure 1: A schematic view of an injector and Figures 2 to 5: Design examples of invention-based control valves. Description of the design examples In Figure 1 an injector with an invention-based control valve 15 is depicted. Via a high-pressure connector 1, fuel is led through an inlet channel 5 to an injection nozzle 7, and through an inflow choke/throttle 9 into a control space 11. The control space 11 is connected through an outflow channel 12 and a discharge choke/throttle 13 to a fuel-return-flow or runback 17. A bypass 14 provides a hydraulic connection between the supply channel 5 and one of the inlet/entry of the control valve 15. The control space 11 is limited by a control piston 19. A nozzle pin 21 joins the control piston 19 which prevents, the fuel, under pressure from getting into the combustion chamber (not illustrated) in-between the injections. Control piston 19 and nozzle pin 21 can also be designed as a single component. The nozzle pin 21 has a cross-section variation from a larger diameter 25 to a smaller diameter 27. With its larger diameter 25 the nozzle pin 21 is guided in a sleeve 28. With a closed discharge choke/throttle 13 the hydraulic force acting on the face surface 33 of the control piston is stronger than the hydraulic force acting on the cross-section variation, because the face surface of the control piston 19 is larger than the ring area/face of the cross-section alteration. As a consequence, the nozzle pin 21 is pressed into a nozzle pin seating 35 and seals the inlet channel 5 to the combustion chamber (not illustrated). If the high pressure jet pump (not illustrated) of the fuel-injection system is not activated, because the engine is not running, the nozzle spring 39 acting on a recess 37 of the nozzle pin 21 presses the injection nozzle 7 against the nozzle pin seating 35, so that the injector is closed. If, through a suitable triggering/activation of the control valve 15, a hydraulic connection between the discharge choke/throttle 13 and the fuel-runback 17 is established, the pressure in the control space 11, and therewith hydraulic force acting, on the face surface 33 of the control piston 19 falls. No sooner this hydraulic force is smaller/weaker than the hydraulic force acting on the cross-section alteration, the nozzle pin 21 opens, so that the fuel can pass through the injection holes (non depicted) into the combustion chamber. This indirect triggering of the nozzle pin 21 through a hydraulic power reinforcing system is necessary because the required forces for a fast opening of the nozzle pin 21 cannot be directly generated by the control valve 15. The so called "control quantity" required in addition to the fuel quantity injected in the combustion chamber reaches the fuel-runback 17 through the inlet choke/throttle 9, the control space 11 and the control valve 15. In-between the injections the discharge choke/throttle 13 is shut through the control valve 15. The control valve 15 can be operated through electromagnetic or Piezoelectric actuators. In Figure 2 an enlarged version of a first design example of an invention-based control valve 15 is shown. The two-part housing, consisting of components 29a and 29b, has a graduated drilling 41. A first section 41a of the graduated drilling, forms the bypass 14 of the control valve 15. This bypass 14 is connected hydraulically with the supply/inlet channel 5 of the injector (not depicted). A second section 41b forms a spring space, whereas a third section 41c of the graduated drilling 41 forms the outlet of the control valve 15. This outlet is hydraulically connected with the fuel- runback 17 (see Figure 1). In the second section 41b of the graduated drilling, the drain channel 12 converges with a discharge choke/throttle 13. The drain channel 12 originates in the control space 11 of the injector. Between the sections 41b and 41c of the graduated drilling 41, a first valve seating 43 is formed. A valve cone 47 is formed on a valve body 45, which acts in tandem with the first valve seating 43. On the valve body 45 upper half of valve cone 47, a stump/butt/stub 49 is formed, which, with its face surface lies adjacent to a piston 51 of a Piezo-actuator (not depicted). Below the valve cone 47, on the valve body 45 a spring plate 53 is formed. Between the spring plate 53 and the housing part 29b a locking spring 55 is clamped, which presses the valve body 45 against the first valve seating 43 and/or against the piston 51 of the (not depicted) Piezo-actuator. In the first switching position of the control valve 15 shown in Figure 2, the Piezo-actuator (not depicted) is not under current, so that the valve cone 47 of the valve body 55 lies on the valve seating. As a result, the control valve 15 is shut. The valve body 45 is thus clamped between the piston 51 and the locking spring 55. The example of an invention-based control valve 15 illustrated in Figure 2, is designed as twice-actuating control valve. For this purpose, at the transition between the first section 41a and 41b of the graduated drilling 41, a second valve seating 57 designed as flat seating is provided. This second valve seating 57 acts jointly with a face surface 59 of the valve body 45. In the switching position of the control valve 15 shown in Figure 2 there is a hydraulic connection between the inlet channel 5 via the bypass 14, the drain channel 12 and the discharge choke/throttle 13, to the control space 11. If the non depicted Piezo-actuator is put under current, the piston 51 in Figure 2 moves downwards, so that the valve cone 47 of the valve body 45 lifts up from the valve seating 43, and for a short time in the switching phase, a hydraulic connection between section 41a of the graduated drilling and the fuel-runback 17 is established. If now the valve body 45 is moved so far in direction of the second valve seating 57 that the face surface 59 of the valve body 45 lies on the second valve seating, the hydraulic connection between the section 41a of the graduated drilling, and/or the bypass 14 and the fuel-runback 17, is again closed. Under an open first valve seating 43 and a closed second valve seating 57, the discharge choke/throttle 13 is open. If the valve body 45 is kept in this second switching position (not depicted), the hydraulic connection between the discharge choke/throttle 13 and the fuel-runback 17 is open. As long as this hydraulic connection exists, the nozzle pin 21 of the injector lifts up from its nozzle pin seating, so that fuel is injected into the combustion chamber of the IC-engine. If the first valve seating 43 is again closed, there exists a hydraulic connection between the section 41a of the graduated drilling, and/or the bypass 14 and the drain channel 12, and the control space 11 is filled with fuel through the supply choke/throttle 9 as well as through the bypass 14. Thereby a fast closing of the nozzle pin 21 is achieved. With the invention-based control valve 15 it is now planned, that for example the diameter of the spring plate 53 is aligned or matched to the diameter of the second section 41b of the graduated drilling 41 in such a way, that a very small gap "s" between the spring plate 53 and the second section 41b of the graduated drilling remains. This gap is dimensioned such, that the valve body 45 is sidewards guided, with the result that the valve cone 47 always hits the same spot of the valve seating 43, if the control valve 15 is being closed. Thereby the slippage and thus the wear of the valve cone 47 and the first valve seating is considerably reduced. On the other hand the gap "s" must be dimensioned so large that the valve cone 47 centers itself in the first valve seating 43. The guiding of the valve body 45 on the external diameter of the spring plate 53 is meant merely to prevent the valve body 54 being significantly deflected on the side. If that should happen while the IC-engine is running, the valve cone 47 would hit the valve seat 43 eccentrically, which could lead to local over loading or stress. Through the force of the closing spring 45 (55?) the valve body 45 would be centered subsequently, in the first valve seating 43. The resultant relative movement between the first valve seating 43 and valve cone 47 (slippage) leads to a wear of the components involved, with the result that the stroke of lift of the valve body 45 between the first switching position and the second switching position significantly alters during the life cycle of the IC-engine. This leads to a deteriorating operating behavior and possibly even to malfunctions. This is because it is well known, that the regulating distance or control path of Piezo-actuators is relatively small. In concrete designs a thickness of the gap "s" of smaller than 0.1mm has proven to be advantageous. Figure 2a shows a top view of the spring plate 53 along the line A-A. From this depiction it is clear that the gap "s" is not available over the entire circumference of the spring plate 53, rather that the spring plate 53 has three flattenings 61. These flattenings 61 enable a by-passing of the flow of the control quantity on the spring plate 53. The Figures 2b and 2c further design forms of invention-based passages are shown. In the design example according to Figure 2b four radially arranged grooves 63 are planned in the spring plate 53, whereas in the design example according to Figure 2c, four bore holes/drills 65 are provided in the spring plate 53. In the design example according to Figure 3 the valve body 45 is guided in the third section 41c of the graduated drilling 41. This means that the diameter of the stump/butt 49 is so chosen, that again a gap "s" gets created between the stump/butt 49 and the third section 41c of the graduated drilling 41. Here also it has been proven that it would be advantageous if the gap "s" is smaller than 0.05mm. Passages at the valve body 45, where the valve body 45 is guided in the graduated drilling 41, must be provided also for this design example; there Figures 3a and 3b depict sectional views along line B-B of two different designs of the invention-based stump/butts 49. With the design example according to Figure 3a, flattenings 61 are provided, whereas with the design example according to Figure 3b grooves 63 are provided, which extend themselves over the complete length of the guiding section between the stump/butt 49 and the third section 41c of the graduated drilling 41. Naturally, the invention is not restricted to the explicitly illustrated forms of the flattenings 61, the grooves 63 and the drillings 65. Figure 4 shows yet another design example of an invention-based control valve 15. With this design example the valve body 45 is guided through a sleeve 67 in the area of the section 41b of the graduated drilling. At the right side of Figure 4 the sleeve 67 is illustrated as ring with an approximately quadratic cross-section, whereas on the left side the sleeve 67 has a L-shaped cross-section. The main difference between these two design forms is in the over-covering HI and H2 between the valve body 45 and the sleeve 67. In order to be able to discharge the control quantity under an open control valve 15, in spite of the narrow gap "s" between the inner diameter of the sleeve 67 and the external diameter of the valve body 45, longitudinal grooves 63 are provided in the sleeve 67 and/or the valve body 45. The detailed views 4a and 4b show two different forms of profiles/cross-sections of the grooves 63. The preferences between these forms depends on the spatial conditions and the control quantity which has to be discharged/evacuated. Figure 5 shows a further design example of an invention-based control valve 15. In this design example, the sleeve 67 is arranged between the spring plate 53 and the closing spring 55. Also in Figure 5, at the right side and the left side different forms of sleeves 67 are shown. Both design forms are common in, that the passages are formed as grooves 63. In the design form shown at the right side in Figure 5, grooves 63 are foreseen additionally on the valve body 54. Moreover the spring plate 53 has drillings 65, which are similarly meant to discharge the control- and leakage quantity from the injector (not depicted) through the control valve 15 into the fuel-runback 17. Claims 1. Injector for an IC-engine with a control valve (15) for opening and closing a nozzle pin (21), - where the control valve (15) consists of a housing (29) and an actuator, - where in the housing (29) a graduated drilling (41) with a spring space (42b) for the intake of a valve body (45) is formed, - where a section (41a) of the graduated drilling (41) is formed as Bypass (14) and a section (41c) of the graduated drilling (41) is formed as outlet, - where a drain channel (12) converges with a second section (41b) of the graduated drilling, with a first valve seating (43), where the valve body (45) has a valve cone (47), acting in cooperation with the first valve seating (43), and where the valve body (45) is pressed by a closing spring (55) provided in the spring space (41b) against a piston (51) of an actuator is thereby characterized, that the valve body (45) is guided or inserted in at least a section (41b, 41c) of the graduated drilling (41), and where in this section (41b, 41c) one or several passages for the control quantity of the injector are provided. 2. Injector according to Claim 1, is thereby characterized, that the inlet (41a) of the control valve (15) remains in contact with a supply/inlet channel (5) of the injector. 3. Injector according to Claim 1 or 2, is thereby characterized, that an outlet (41c) of the control valve (15) remains in contact with a fuel-runback/reserve-flow (17). 4. Injector according to one of the above mentioned claims, is thereby characterized, that the closing spring (55) acts on the valve body (45) in opposite direction to the direction of operation of the actuator. 5. Injector according to Claim 4, is thereby characterized, that the closing spring (55) supports itself at least indirectly against the housing (29) and against a spring plate (53) of the valve body (45). 6. Injector according to one of the above mentioned claims, is thereby characterized, that the valve body (45) is guided in the area of the outlet (41c) and/or in the area of the spring space (41b). 7. Injector according to one of the Claims 5 and 6, is thereby characterized, that the valve body (45) is guided to the spring plate (53). 8. Injector according to one of the Claims 5 to 7, is thereby characterized, that in the spring space (41b) a sleeve (67) is provided, and that the valve body (45) is guided from the sleeve (67). 9. Injector according to one of the above mentioned claims, is thereby characterized, that the passage or passages are formed as grooves (63), flattenings (61) and/or longitudinal bores/drillings (65) running longitudinal to the valve body (45). 10. Injector according to one of the above mentioned claims, is thereby characterized, that at the passage between the inlet (41a) and the spring space (41b) a second valve seating (57) is formed, and that a face surface (33) of the valve body (45) is co-acting with the valve seating (57). 11. Injector according to one of the above mentioned claims, is thereby characterized, that the housing (29) is formed of two pieces. 12. Injector according to one of the above mentioned claims, is thereby characterized, that the control valve (15) is a 2/3-control valve. 13. Injector according to one of the above mentioned claims, is thereby characterized, that the valve body (45) is activated by a Piezo-actuator. 14. Injector according to one of the above mentioned claims, is thereby characterized, that the injector is used in a Common-Rail-fuel-injection system.

Full Text

Injector of a Fuel-Iniection-Svstem of an Internal Combustion Engine (IC-Engine)
State of the art of technology
The invention relates to an injector for an IC-engine with a control valve to open and to close a nozzle pin, where the control valve has a valve body with a valve cone, which acts in conjunction with a valve seating of a housing of the control valve. In this injector, the valve body is pressed against a plunger of an actuator by a locking/closing spring and is centered over the valve seating.
The invention-based injector for an IC-engine with a control valve for the opening and closing of a nozzle pin where the control valve includes a housing and an actuator where a graduated drilling with a spring space for the seating of a valve body is formed in the housing where a section of the cascade/graduated drilling is formed as inlet and a section of the graduated drilling as outlet, and with a first valve seating, where the valve body has a valve cone which is co-acting with the first valve seating and where the valve body is pressed by a locking spring arranged in the spring space against the piston of an actuator, it is visualized that the valve body is inserted/guided in at least one section of the graduated drilling, and where there are one or several passages for the control-quantity of the injector in this section..
Advantages of the invention
Since the valve body is guided in at least a section of the graduated drilling, it is ensured, that the valve cone of the valve body almost always meets the housing in the center with minimum slippage. Thereby, first the local overloading of the valve cone and the valve seating is avoided, and the wear of the valve seating and valve cone is reduced. Both effects lead to the fact, that there is only a small alteration of the valve lift or stroke, during the running of the IC-engine with the result that the operating behavior of the IC-engine remains almost constant during the complete life-cycle. In this context, the size of

the play (space) between the graduated drilling and the guide section of the valve body has to be chosen so large, that the valve body in the closing position of the control valve centers itself to the valve seating of the housing, for, only then the control valve gets tightly closed.
Advantageous variants of the invention-based injector that provide for one inlet of the control valve remains in contact with one control space of the injector, whereas one outlet of the control valve remains in contact with a reverse flow of the fuel.
In a further advantageous design of the invention it is planned, that the locking spring acts on the valve body transverse to the direction of operation of the actuator. Thereby it is guaranteed that the valve body always takes a defined position and that the control valve is closed under an actuator switched on without current.
Thereby it is provenly advantageous, if the closing spring supports itself at least indirectly against the housing and a spring-plate of the valve element.
The guiding of the valve body can be done preferably in the area of the outlet and/or in the area of the spring area/space. Thereby it is alternatively possible that the valve body is guided at the spring-plate or that in the spring area a sleeve (casing) is provided and that the valve body is guided from the sleeve.
In order that the control quantity can flow through the invention-based control valve despite the insertion of the valve body in the housing, the passages are formed or designed alternatively as grooves or flattenings and/or longitudinal bores/drills running longitudinal to the valve body. Thereby the flow-resistance of the control valve in open position can be reduced to such an extent, that the functioning of the injector is not negatively affected by guiding the valve body in the graduated drilling.
In order to simplify the production and assembly, the housing can be designed in two parts. In this context, the control valve can be a separate component as also one that is

integrated in the injector. In the latter case, the housing of the control valve is at the same time the housing of the injector.
Advantageously the control valve can be designed as 2/3-way-control valve. Thereby multiple injections can be realized more easily; there are further possibilities to shape or form the course of injection.
In order to take optimum advantage of the invention-based injector with the invention-based control valve, the valve body can be activated with a Piezo-actuator. Extremely fast control movements are thereby possible. As a result of the design/form of the invention-based control valve, the seating in the housing and the valve cone on the valve body barely wears out, and therefore the functioning of the control valve during the complete life-cycle of the IC-engine is assured.
The invention-based injector is preferred for use in Common-Rail fuel-injection-systems.
Further advantages and ideal design forms can be seen from the following drawing, its description and the Patent Claims. All distinguishing characteristics/parameters described in the drawing, its description and the Patent Claims can be significant for the invention either individually or in optional combination with one another.
Drawings
Following are illustrated:
Figure 1: A schematic view of an injector and
Figures 2 to 5: Design examples of invention-based control valves.

Description of the design examples
In Figure 1 an injector with an invention-based control valve 15 is depicted. Via a high-pressure connector 1, fuel is led through an inlet channel 5 to an injection nozzle 7, and through an inflow choke/throttle 9 into a control space 11. The control space 11 is connected through an outflow channel 12 and a discharge choke/throttle 13 to a fuel-return-flow or runback 17. A bypass 14 provides a hydraulic connection between the supply channel 5 and one of the inlet/entry of the control valve 15.
The control space 11 is limited by a control piston 19. A nozzle pin 21 joins the control piston 19 which prevents, the fuel, under pressure from getting into the combustion chamber (not illustrated) in-between the injections. Control piston 19 and nozzle pin 21 can also be designed as a single component. The nozzle pin 21 has a cross-section variation from a larger diameter 25 to a smaller diameter 27. With its larger diameter 25 the nozzle pin 21 is guided in a sleeve 28.
With a closed discharge choke/throttle 13 the hydraulic force acting on the face surface 33 of the control piston is stronger than the hydraulic force acting on the cross-section variation, because the face surface of the control piston 19 is larger than the ring area/face of the cross-section alteration. As a consequence, the nozzle pin 21 is pressed into a nozzle pin seating 35 and seals the inlet channel 5 to the combustion chamber (not illustrated).
If the high pressure jet pump (not illustrated) of the fuel-injection system is not activated, because the engine is not running, the nozzle spring 39 acting on a recess 37 of the nozzle pin 21 presses the injection nozzle 7 against the nozzle pin seating 35, so that the injector is closed.
If, through a suitable triggering/activation of the control valve 15, a hydraulic connection between the discharge choke/throttle 13 and the fuel-runback 17 is established, the pressure in the control space 11, and therewith hydraulic force acting, on the face surface

33 of the control piston 19 falls. No sooner this hydraulic force is smaller/weaker than the hydraulic force acting on the cross-section alteration, the nozzle pin 21 opens, so that the fuel can pass through the injection holes (non depicted) into the combustion chamber. This indirect triggering of the nozzle pin 21 through a hydraulic power reinforcing system is necessary because the required forces for a fast opening of the nozzle pin 21 cannot be directly generated by the control valve 15. The so called "control quantity" required in addition to the fuel quantity injected in the combustion chamber reaches the fuel-runback 17 through the inlet choke/throttle 9, the control space 11 and the control valve 15. In-between the injections the discharge choke/throttle 13 is shut through the control valve 15. The control valve 15 can be operated through electromagnetic or Piezoelectric actuators.
In Figure 2 an enlarged version of a first design example of an invention-based control valve 15 is shown. The two-part housing, consisting of components 29a and 29b, has a graduated drilling 41. A first section 41a of the graduated drilling, forms the bypass 14 of the control valve 15. This bypass 14 is connected hydraulically with the supply/inlet channel 5 of the injector (not depicted). A second section 41b forms a spring space, whereas a third section 41c of the graduated drilling 41 forms the outlet of the control valve 15. This outlet is hydraulically connected with the fuel- runback 17 (see Figure 1).
In the second section 41b of the graduated drilling, the drain channel 12 converges with a discharge choke/throttle 13. The drain channel 12 originates in the control space 11 of the injector.
Between the sections 41b and 41c of the graduated drilling 41, a first valve seating 43 is formed. A valve cone 47 is formed on a valve body 45, which acts in tandem with the first valve seating 43. On the valve body 45 upper half of valve cone 47, a stump/butt/stub 49 is formed, which, with its face surface lies adjacent to a piston 51 of a Piezo-actuator (not depicted). Below the valve cone 47, on the valve body 45 a spring plate 53 is formed. Between the spring plate 53 and the housing part 29b a locking spring 55 is clamped, which presses the valve body 45 against the first valve seating 43 and/or

against the piston 51 of the (not depicted) Piezo-actuator. In the first switching position of the control valve 15 shown in Figure 2, the Piezo-actuator (not depicted) is not under current, so that the valve cone 47 of the valve body 55 lies on the valve seating. As a result, the control valve 15 is shut. The valve body 45 is thus clamped between the piston 51 and the locking spring 55.
The example of an invention-based control valve 15 illustrated in Figure 2, is designed as twice-actuating control valve. For this purpose, at the transition between the first section 41a and 41b of the graduated drilling 41, a second valve seating 57 designed as flat seating is provided. This second valve seating 57 acts jointly with a face surface 59 of the valve body 45. In the switching position of the control valve 15 shown in Figure 2 there is a hydraulic connection between the inlet channel 5 via the bypass 14, the drain channel 12 and the discharge choke/throttle 13, to the control space 11.
If the non depicted Piezo-actuator is put under current, the piston 51 in Figure 2 moves downwards, so that the valve cone 47 of the valve body 45 lifts up from the valve seating 43, and for a short time in the switching phase, a hydraulic connection between section 41a of the graduated drilling and the fuel-runback 17 is established. If now the valve body 45 is moved so far in direction of the second valve seating 57 that the face surface 59 of the valve body 45 lies on the second valve seating, the hydraulic connection between the section 41a of the graduated drilling, and/or the bypass 14 and the fuel-runback 17, is again closed. Under an open first valve seating 43 and a closed second valve seating 57, the discharge choke/throttle 13 is open.
If the valve body 45 is kept in this second switching position (not depicted), the hydraulic connection between the discharge choke/throttle 13 and the fuel-runback 17 is open. As long as this hydraulic connection exists, the nozzle pin 21 of the injector lifts up from its nozzle pin seating, so that fuel is injected into the combustion chamber of the IC-engine.
If the first valve seating 43 is again closed, there exists a hydraulic connection between the section 41a of the graduated drilling, and/or the bypass 14 and the drain channel 12,

and the control space 11 is filled with fuel through the supply choke/throttle 9 as well as through the bypass 14. Thereby a fast closing of the nozzle pin 21 is achieved.
With the invention-based control valve 15 it is now planned, that for example the diameter of the spring plate 53 is aligned or matched to the diameter of the second section 41b of the graduated drilling 41 in such a way, that a very small gap "s" between the spring plate 53 and the second section 41b of the graduated drilling remains. This gap is dimensioned such, that the valve body 45 is sidewards guided, with the result that the valve cone 47 always hits the same spot of the valve seating 43, if the control valve 15 is being closed. Thereby the slippage and thus the wear of the valve cone 47 and the first valve seating is considerably reduced.
On the other hand the gap "s" must be dimensioned so large that the valve cone 47 centers itself in the first valve seating 43. The guiding of the valve body 45 on the external diameter of the spring plate 53 is meant merely to prevent the valve body 54 being significantly deflected on the side. If that should happen while the IC-engine is running, the valve cone 47 would hit the valve seat 43 eccentrically, which could lead to local over loading or stress. Through the force of the closing spring 45 (55?) the valve body 45 would be centered subsequently, in the first valve seating 43. The resultant relative movement between the first valve seating 43 and valve cone 47 (slippage) leads to a wear of the components involved, with the result that the stroke of lift of the valve body 45 between the first switching position and the second switching position significantly alters during the life cycle of the IC-engine. This leads to a deteriorating operating behavior and possibly even to malfunctions. This is because it is well known, that the regulating distance or control path of Piezo-actuators is relatively small. In concrete designs a thickness of the gap "s" of smaller than 0.1mm has proven to be advantageous.
Figure 2a shows a top view of the spring plate 53 along the line A-A. From this depiction it is clear that the gap "s" is not available over the entire circumference of the spring plate 53, rather that the spring plate 53 has three flattenings 61. These flattenings 61 enable a

by-passing of the flow of the control quantity on the spring plate 53. The Figures 2b and 2c further design forms of invention-based passages are shown. In the design example according to Figure 2b four radially arranged grooves 63 are planned in the spring plate 53, whereas in the design example according to Figure 2c, four bore holes/drills 65 are provided in the spring plate 53.
In the design example according to Figure 3 the valve body 45 is guided in the third section 41c of the graduated drilling 41. This means that the diameter of the stump/butt 49 is so chosen, that again a gap "s" gets created between the stump/butt 49 and the third section 41c of the graduated drilling 41. Here also it has been proven that it would be advantageous if the gap "s" is smaller than 0.05mm.
Passages at the valve body 45, where the valve body 45 is guided in the graduated drilling 41, must be provided also for this design example; there Figures 3a and 3b depict sectional views along line B-B of two different designs of the invention-based stump/butts 49. With the design example according to Figure 3a, flattenings 61 are provided, whereas with the design example according to Figure 3b grooves 63 are provided, which extend themselves over the complete length of the guiding section between the stump/butt 49 and the third section 41c of the graduated drilling 41. Naturally, the invention is not restricted to the explicitly illustrated forms of the flattenings 61, the grooves 63 and the drillings 65.
Figure 4 shows yet another design example of an invention-based control valve 15. With this design example the valve body 45 is guided through a sleeve 67 in the area of the section 41b of the graduated drilling.
At the right side of Figure 4 the sleeve 67 is illustrated as ring with an approximately quadratic cross-section, whereas on the left side the sleeve 67 has a L-shaped cross-section. The main difference between these two design forms is in the over-covering HI and H2 between the valve body 45 and the sleeve 67.

In order to be able to discharge the control quantity under an open control valve 15, in spite of the narrow gap "s" between the inner diameter of the sleeve 67 and the external diameter of the valve body 45, longitudinal grooves 63 are provided in the sleeve 67 and/or the valve body 45. The detailed views 4a and 4b show two different forms of profiles/cross-sections of the grooves 63. The preferences between these forms depends on the spatial conditions and the control quantity which has to be discharged/evacuated.
Figure 5 shows a further design example of an invention-based control valve 15. In this design example, the sleeve 67 is arranged between the spring plate 53 and the closing spring 55. Also in Figure 5, at the right side and the left side different forms of sleeves 67 are shown. Both design forms are common in, that the passages are formed as grooves 63. In the design form shown at the right side in Figure 5, grooves 63 are foreseen additionally on the valve body 54. Moreover the spring plate 53 has drillings 65, which are similarly meant to discharge the control- and leakage quantity from the injector (not depicted) through the control valve 15 into the fuel-runback 17.

Claims
1. Injector for an IC-engine with a control valve (15) for opening and closing a nozzle pin (21),
- where the control valve (15) consists of a housing (29) and an actuator,
- where in the housing (29) a graduated drilling (41) with a spring space (42b) for the intake of a valve body (45) is formed,
- where a section (41a) of the graduated drilling (41) is formed as Bypass (14) and a section (41c) of the graduated drilling (41) is formed as outlet,
- where a drain channel (12) converges with a second section (41b) of the graduated drilling, with a first valve seating (43),
where the valve body (45) has a valve cone (47), acting in cooperation with the first valve seating (43), and
where the valve body (45) is pressed by a closing spring (55) provided in the spring space (41b) against a piston (51) of an actuator is thereby characterized, that the valve body (45) is guided or inserted in at least a section (41b, 41c) of the graduated drilling (41), and where in this section (41b, 41c) one or several passages for the control quantity of the injector are provided.
2. Injector according to Claim 1, is thereby characterized, that the inlet (41a) of the
control valve (15) remains in contact with a supply/inlet channel (5) of the injector.
3. Injector according to Claim 1 or 2, is thereby characterized, that an outlet (41c) of the control valve (15) remains in contact with a fuel-runback/reserve-flow (17).
4. Injector according to one of the above mentioned claims, is thereby characterized, that the closing spring (55) acts on the valve body (45) in opposite direction to the direction of operation of the actuator.

5. Injector according to Claim 4, is thereby characterized, that the closing spring (55) supports itself at least indirectly against the housing (29) and against a spring plate (53) of the valve body (45).
6. Injector according to one of the above mentioned claims, is thereby characterized, that the valve body (45) is guided in the area of the outlet (41c) and/or in the area of the spring space (41b).
7. Injector according to one of the Claims 5 and 6, is thereby characterized, that the valve body (45) is guided to the spring plate (53).
8. Injector according to one of the Claims 5 to 7, is thereby characterized, that in the spring space (41b) a sleeve (67) is provided, and that the valve body (45) is guided from the sleeve (67).
9. Injector according to one of the above mentioned claims, is thereby characterized, that the passage or passages are formed as grooves (63), flattenings (61) and/or longitudinal bores/drillings (65) running longitudinal to the valve body (45).
10. Injector according to one of the above mentioned claims, is thereby characterized, that at the passage between the inlet (41a) and the spring space (41b) a second valve seating (57) is formed, and that a face surface (33) of the valve body (45) is co-acting with the valve seating (57).
11. Injector according to one of the above mentioned claims, is thereby characterized, that the housing (29) is formed of two pieces.
12. Injector according to one of the above mentioned claims, is thereby characterized, that the control valve (15) is a 2/3-control valve.

13. Injector according to one of the above mentioned claims, is thereby characterized, that the valve body (45) is activated by a Piezo-actuator.
14. Injector according to one of the above mentioned claims, is thereby characterized, that the injector is used in a Common-Rail-fuel-injection system.

Documents:

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Patent Number

268549

Indian Patent Application Number

2699/CHENP/2007

PG Journal Number

36/2015

Publication Date

04-Sep-2015

Grant Date

03-Sep-2015

Date of Filing

21-Jun-2007

Name of Patentee

ROBERT BOSCH GmbH

Applicant Address

POSTFACH 30 02 20,D-70442 STUTTGART,GERMANY

Inventors:

#	Inventor's Name	Inventor's Address
1	HEINZ, RUDOLF	ELTINGER WEG 26, 71272 RENNINGEN, GERMANY
2	STOECKLEIN, WOLFGANG	LUDWIGSTRASSE 34B, 70176 STUTTGART, GERMANY

PCT International Classification Number

F02M 47/02

PCT International Application Number

PCT/EP05/56138

PCT International Filing date

2005-11-22

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102004061800.3	2004-12-22	Germany