WO2013045688A1

WO2013045688A1 - An injection valve having wet actuator and simplified hydraulic transmission

Info

Publication number: WO2013045688A1
Application number: PCT/EP2012/069316
Authority: WO
Inventors: Alp Durus; Dogan Vardar; Duygu Kandemir
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2011-10-01
Filing date: 2012-10-01
Publication date: 2013-04-04
Anticipated expiration: 2014-04-01

Abstract

The subject matter invention is an injection valve (10) comprising an input region (11); an upper shoe (21) provided at the continuation of said input region (11); an actuator (24) provided at the continuation of said upper shoe (21); a piston (23) provided at the continuation of said actuator (24); characterized by comprising at least one bearing (213) provided on the upper shoe (21) in order for the actuator (24) to be connected to the upper shoe (21); at least one bearing (233) provided on the piston (23) in order to connect the actuator (24) to the piston (23) in a direct manner; and at least one spring (22) which is bedded between said bearings (213, 233) and which is positioned at a vicinity of the actuator (24) and which will permit liquid inlet-outlet to/from the actuator (24).

Description

SPECIFICATION

AN INJECTION VALVE HAVING WET ACTUATOR AND SIMPLIFIED HYDRAULIC

TRANSMISSION

TECHNICAL FIELD

The present invention relates to an injection valve which is used for spraying fuel into the combustion chamber in internal combustion engines and which has an actuator and which has a valve piston provided at the continuation of said actuator and driven by the actuator.

PRIOR ART

Said injection valves are used for spraying fuel into the combustion chamber in internal combustion engines. The injection valves are classified according to different operation principles thereof. The injection valves, which have piezo electric members, are called piezo injection valves. Piezo injection valves are essentially described in WO 2005 050003 (A1 ).

Piezo injection valves have a piezo electric member which shortens and lengthens with respect to current. Piezo electric members are essentially disclosed in the patent DE 199 46 835 A1 . Said piezo electric member is called actuator in the injection valve. The actuators exist in a bedded manner into the silicon inside a cylindrical bushing. This is disclosed in the patent application DE 102 009 046355 (A1 ). Shoes are placed for transferring the movement at the lower and upper parts of the actuators. The bedding of the actuators inside the shoes is essentially disclosed in the patent EP 2 031 669 A1 . The actuators shorten and lengthen under a certain current, and movement is transferred to the pistons in order for the drive to be transferred to the needle region. The piston, existing in the needle region, increases movement at a predetermined proportion and it transmits the movement to the valve piston and provides the injection valve to begin the spraying process.

Since the actuator is inside a bearing and since it has silicon filling inside the bearing, the cooling of the actuator, which is heated by electrical current, is retarded and this affects the general performance of the injection valve. Moreover, during the transmission of the drive, produced by the actuator, to the pistons and during the transmission thereof to the valve piston, pluralities of pieces with complex shapes are used. During operation, the pieces, which have pluralities of complex shapes, can be damaged and they become useless and as a result of this, the injection valve becomes useless. As a result, because of the abovementioned problems, an improvement is required in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to an injection valve having a valve piston which is driven by an actuator which is directly cooled by the fuel existing inside the injection valve and by a piston which is in direct connection to said actuator, in order to eliminate the abovementioned problems and to bring new advantages to the related technical field.

The main object of the present invention is to provide an injection valve where the actuator is directly cooled by the fuel existing inside the injection valve. Another object of the present invention is to provide an injection valve where the valve piston is driven directly by a piston connected to the actuator.

Another object of the present invention is to provide an injection valve where drive transmission is realized between the valve piston and the actuator by small number of pieces which have simple shapes.

In order to realize all of the abovementioned objects and the objects which are to be obtained from the detailed description below, the present invention relates to an injection valve which is used for spraying fuel to the combustion chamber in internal combustion engines and comprising a body; an input region provided on said body; an upper shoe provided at the continuation of said input region; an actuator provided at the continuation of said upper shoe; a piston provided at the continuation of said actuator; a valve piston region provided at the continuation of said piston. Said injection valve is characterized by comprising at least one bearing provided on the upper shoe in order for the actuator to be connected to the upper shoe; at least one bearing provided on the piston in order to connect the actuator to the piston in a direct manner; and at least one spring which is bedded between said bearings and which is positioned at a vicinity of the actuator and which will permit liquid inlet-outlet to/from the actuator. In a preferred embodiment of the subject matter invention, there is at least one strengthening body which is in connection to said valve piston region; and there is at least one valve piston which is provided in said strengthening body and which has a space to the piston so as to be able to receive the drive applied by the piston.

In another preferred embodiment of the subject matter invention , the spring is connected in a pre-tensioned manner.

In another preferred embodiment of the subject matter invention, the strengthening body comprises a narrow part provided at a vicinity of the piston; a wide part provided at a vicinity of the valve piston; and a spring part provided at the continuation of said wide part.

In another preferred embodiment of the subject matter invention, there is a lower shoe where the actuator is bedded ; and there is a piston which is provided at the continuation of said lower shoe and which is driven by the lower shoe. In order for the embodiment and the advantages of the subject matter invention to be understood in the best manner with the additional elements, it has to be evaluated with the detailed description and with the figures explained below.

BRIEF DESCRIPTION OF THE FIGURES

In Figure 1 , the general cross sectional view of an injection valve with a piezo electric member is given.

In Figure 2, the zoomed cross sectional view of the injection valve is given.

In Figure 3, the zoomed cross sectional view of an alternative embodiment of the injection valve is given.

REFERENCE NUMBERS

10 Injection Valve

1 1 Input Region

12 Needle Region

13 Body

20 Actuator Region

21 Upper Shoe

211 First Part

212 Second Part 213 Seating Part

214 Tab

22 Spring

23 Piston

231 Upper Part

232 Lower Part

233 Seating Edge

24 Actuator

25 Lower Shoe

30 Valve Piston Region

31 Strengthening Body

311 Narrow Part

312 Wide Part

313 Spring Part

314 Inclined Edge

315 Flat Edge

32 Valve Piston

321 Spring Bearing

322 Valve Piston Spring

323 First Region

324 Second Region

325 Long Edge

326 Short Edge

X: Movement Direction

THE DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter improvement is explained with references to examples without forming any restrictive effect in order to make the subject more understandable. Accordingly, in the detailed description and in the figures below, an injection valve (10) is disclosed which is used for spraying fuel to the combustion chamber in internal combustion engines and which has a piezo electric member.

With reference to Figure 1 , an injection valve (10) is illustrated. Said injection valve (10) essentially comprises an input region (11 ) through which the fuel enters into the injection valve (10); a needle region (12) through which the fuel is sprayed to the combustion chamber (not illustrated in the figure) by the injection valve (10); and an actuator region (20) which is provided between said needle region (12) and said input region (1 1 ); and a valve piston region (30) provided at the continuation of said actuator region (20). The actuator region (20), said vaive piston region (30), the needle region (12) and the input region (1 1 ) generally exist on a body (13) which has a circular cross section. With reference to Figure 2, there is an upper shoe (21 ) which is in connection with the actuator region (20). Said upper shoe (21 ) is positioned in X direction of the input region (1 1 ). The upper shoe (21 ) has an inverse Y-like view when viewed from the cross section. The upper shoe (21 ) comprises three parts. The part, where the upper shoe (21 ) is connected to the input region (1 1 ) is defined as the first part (211 ). Said first part (21 1 ) has a fixed diameter and it is embodied as a smooth cylindrical form. There is a second part (212) which is provided at the continuation of the first part (21 1 ). The diameter of said second part (212) is embodied so as to be bigger than the diameter of the first part (21 1 ). There is one tab (214) which is connected to the second part (212). Said tab (214) has a circular cross section and it has an O-like view when viewed from above. The tab (214) is positioned so as to be adjacent to the edge of the second part (212) in X direction and so as to be adjacent to the cross section edge. The edge of the second part (212) which remains inside the tab (214) is defined as the seating part (213). There is a drive member (22) which is in connection with the tab (214). Said drive member (22) is a spring. Said spring (22) is positioned so as to be adjacent to the edge of the tabs (214) in a cross sectional manner. There is a piston (23) which is in connection with the other end of the spring (22) in the X direction. Said piston (23) has a Y-like view. The part of the piston (23) which is in connection with the spring (22) is defined as the tab (214) and it has the same characteristics with the tab (214) in the upper shoe (21 ). There is the upper part (231 ) of the piston (23) which is in connection with the tab (214). The tab (214) is positioned so as to be adjacent to the edges of said upper part (231 ) in a cross sectional manner. The surface of the upper part (231 ), which remains inside the tab (214), is defined as the seating edge (233). The diameters of said seating edge (233) and of the seating part (213) in the upper shoe (21 ) are the same. There is a lower part (232) which is in connection with the upper part (231 ). The diameter of said lower part (232) is embodied so as to be smaller than the diameter of the upper part (231 ). The upper shoe (21 ), the spring (22) and the piston (23) are coaxial. There is an actuator (24) which is in connected form between the seating part (213) and the seating edge (233). Said actuator (24) will be inside the spring (22), and the upper shoe (21 ) is positioned so as to be coaxial with the piston (23) and the spring (22). The diameter of the actuator (24) is equal to the diameter of the seating part (213) and of the seating edge (233). There are electrical cables (not illustrated in the figure) which are in connection to the actuator (24). With reference to Figure 3, there is a strengthening body (31 ) which exists in the valve piston region (30) and which is in connection to the body (13) of the injection valve (10). Said strengthening body (31 ) comprises three main parts. These parts are the narrow part (31 1 ); wide part (312) and the spring part (313). Said narrow part (31 1 ) is positioned at a vicinity of the lower part (232) of the piston (23) and so that there is a certain space between itself and the piston (23). At the continuation of the narrow part (31 1 ), said wide part (312) is provided. The passage from the narrow part (31 1 ) to the wide part (312) is provided by an inclined edge (314) and said inclined edge (314) is positioned so as to be at a certain distance from the bottom edge in X direction of the piston (23). The inclined edge (314) realizes a certain angle with the narrow part (31 1 ). The diameter of the wide part (312) is greater than the diameter of the narrow part (31 1 ). At the continuation of the wide part (312), said spring part (313) is provided by means of a flat edge (315). The flat edge (315) realizes a substantial right angle with the spring part (313) and with the wide part (312). The diameter of the spring part (313) is smaller than the diameter of the narrow part (31 1 ) and of the wide part (312). The strengthening body (31 ) is coaxial with the injection valve (10) and with the actuator region (20). There is a valve piston (32) which is in connected form to the valve piston region (30). Said valve piston (32) generally comprises two regions. A first region (323), which is at a vicinity of the wide part (312) of the strengthening body (31 ) and which is positioned so that there is a certain opening between the piston (23) and itself in the X direction, is in connection with the valve piston (32). Said first region (323) has a smooth cylindrical shape. At the continuation of the first region (323), there is a second region (324) in connection. Said second region (324) has a flat cylindrical shape and the finishing point in X direction is circular. The first region (323) and the second region (324) are coaxial and in general, the valve piston (32) is coaxial with the valve piston region (30) and with the actuator region (20). There is a spring bearing (321 ) which is in connection with the valve piston (32) so as to be adjacent to the edge where the first region (323) and the second region (324) join . Said spring bearing (321 ) has an L-letter like view when viewed from the cross section . The spring bearing (321 ) comprises a long edge (325) which is in connection with the valve piston (32) and a short edge (326) which is provided at the continuation of said long edge (325). Said short edge (326) is positioned so as to make a substantially vertical angle to the long edge (325) and so as to be adjacent to the part which is connected to the first region (323) and to the second region (324) of the valve piston (32). The spring bearing (321 ) is generally provided at a vicinity of the spring part (313) of the strengthening body (31 ). The long edge (325) is at a vicinity of the flat edge (315). A valve piston spring (322) is in connection to the spring bearing (321 ). Said valve piston spring (322) is positioned on the short edge (326). In general, injection valves (10) are used for spraying fuel to the combustion chamber (not illustrated in the figure) in internal combustion engines (not illustrated in the figure). The fuel, which enters into the injection valve (10) through the input region (11 ), is transferred to the needle region (12) by the members (not illustrated in the figure) of the fuel injection valve and the fuel is sprayed from the needle region (12) to the combustion chamber. The body (13) forms a connection surface for all of the members (not illustrated in the figure) of the injection valve (10). The upper shoe (21 ) existing in the actuator region (20) forms a connection surface for the actuator (24) and for the spring (22); and forms a bearing for said electrical cables. The second part (212) existing on the upper shoe (21 ) provides the required diameter expansion and it forms the substantial area for connection to the tab (214) and to the seating part (213). The seating part (213) forms a bearing for the actuator (24) and while the tabs (214) form a seating surface for the spring (22), it facilitates the bedding of the actuator (24) in a fixed manner. The spring (22) is in a pre-tensioned form. The actuator (24) elongates and shortens with respect to electrical current and it provides the required axial movement inside the injection valve (10). The spring (22) provides the elongated actuator (24) to return to the initial position thereof. The piston (23) provides the drive, produced by the actuator (24), to be transmitted to the valve piston (32). The strengthening body (31 ), existing in the valve piston region (30), defines an axis for the valve piston (32); and it helps the drive to be transferred in a hydraulic manner from the piston (23) to the valve piston (32). The valve piston (32) takes the drive from the piston (23) in a hydraulic manner and it transfers the movement to the needle region (12) and it facilitates the start of the spraying process. The regions (311 , 312, 313) defined on the strengthening body (31 ) provides the required area for the operation of the vale piston spring (322). The valve piston spring (322) provides the valve piston (32) to move within the desired limits.

After the signals, required for the spraying process to begin, are sent to the injection valve (10), electrical current is applied to the actuator (24). The actuator (24), which is elongated in X direction under the electrical current, drives the piston (23) and the piston (23) begins displacement in X direction. The fuel, existing in the low pressure region (not illustrated in the figure), is pressed by the piston (23) and the pressed fuel drives the valve piston (32) in X direction. As a result of the movement of the valve piston (32), the members existing in the needle region (12) are activated and the spraying process begins. When the spraying process is to be stopped , the electrical current applied to the actuator (24) is interrupted and the actuator (24) returns to the initial position thereof with the help of the spring (22) thereon. By means of this, the redrawn piston (23) and the valve piston (32) stop the spraying process. Under harsh operation conditions, the temperature of the actuator (24) increases which is subject to electrical current. In order to decrease the temperature of the actuator (24) which is under high temperature continuously, the fuel existing in the low pressure region is used. The fuel , which passes to the actuator (24) through the spring (22), provides the continuous cooling of the actuator (24). By means of this, the temperature of the actuator (24) remains at the desired level. Cooling with fuel is more efficient than the decreasing of the temperature of the actuator (24) which is bedded inside the silicon in the prior art.

The electrical cables, which are in connection with the actuator (24), should be insulated in a firm manner inside the liquid. In case the electrical cables, which exist in a free manner in the low pressure region, are insulated from the connection points thereof by a plastic insulation technique (not illustrated in the figure) known in the art, there is no arc or short circuit problem. With reference to Figure 4, there is a second alternative in the actuator region (20) in order to provide the connection of the piston (23) and the actuator (24) to each other. In said alternative, the actuator (24) is connected to the seating edge (233) in a lower shoe (25) and the spring (22) is connected to the tab (214) existing on the lower shoe (25). The lower shoe (25) transfers the drive, obtained from the actuator (24), to the piston (23). The piston (23) is embodied so as to correspond to the edges of the lower shoe (25) in X direction and the lower shoe (25) and the piston (23) can seat completely to each other.

The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.

Claims

An injection valve (10) which is used for spraying fuel to the combustion chamber in internal combustion engines and comprising a body (13); an input region (1 1 ) provided on said body (13); an upper shoe (21 ) provided at the continuation of said input region (1 1 ); an actuator (24) provided at the continuation of said upper shoe (21 ); a piston (23) provided at the continuation of said actuator (24); a valve piston region (30) provided at the continuation of said piston (23), characterized by comprising at least one bearing (213) provided on the upper shoe (21 ) in order for the actuator (24) to be connected to the upper shoe (21 ); at least one bearing (233) provided on the piston (23) in order to connect the actuator (24) to the piston (23) in a direct manner; and at least one spring (22) which is bedded between said bearings (213, 233) and which is positioned at a vicinity of the actuator (24) and which will permit liquid inlet-outlet to/from the actuator (24).

An injection valve (10) according to Claim 1 , characterized in that there is at least one strengthening body (31 ) which is in connection to said valve piston region (30); and there is at least one valve piston (32) which is provided in said strengthening body (31 ) and which has a space to the piston (23) so as to be able to receive the drive applied by the piston (23).

An injection valve (10) according to Claim 1 or 2, characterized in that the spring (22) is connected in a pre-tensioned manner.

An injection valve (10) according to any one of the preceding claims, characterized in that the strengthening body (31 ) comprises a narrow part (311 ) provided at a vicinity of the piston (23); a wide part (312) provided at a vicinity of the valve piston (32); and a spring part (313) provided at the continuation of said wide part (312).

An injection valve (10) according to Claim 1 , characterized in that there is a lower shoe (25) where the actuator (24) is bedded; and there is a piston (23) which is provided at the continuation of said lower shoe (25) and which is driven by the lower shoe (25).