JP5886830B2 - High pressure pump - Google Patents

Description

  The present invention relates to a high-pressure pump, particularly a radial plunger pump or an in-line plunger pump. In particular, the present invention relates to the field of fuel pumps for fuel injection devices of air compression self-ignition internal combustion engines. However, the high pressure pump can also function as a plunger pump that pumps other suitable fluids.

  German Offenlegungsschrift 19515191 discloses a high-pressure fuel pump. The high-pressure fuel pump has a barrel whose upper portion is exposed outside a head cover which is a component of the engine housing. The remaining part of the high-pressure fuel pump is accommodated in the accommodation hole of the head cover. A pump cam is mounted on the valve camshaft that drives the intake / discharge valves and drives the high pressure fuel pump. Since the time response when the fuel under pressure is discharged is controlled by operating the solenoid valve, the accuracy of controlling the fuel supply is further improved.

  The high-pressure fuel pump disclosed in German Patent Application No. 19515191 is a pump in which the flow of fuel is throttled on the suction side, and has a plurality of drawbacks. The disadvantages are high noise, low controllability and mechanical vibration due to cavitation occurring in the supply line to the inlet valve. Here, the compression wave between the metering unit and the intake valve has a disadvantageous effect on functionality.

  The high-pressure pump according to the invention with the features of claim 1 has the advantage of realizing an improved configuration, in particular that allows fuel metering and a compact configuration. In particular, the weighing unit or the like can be omitted, and the manufacturing cost is significantly reduced.

  Due to the measures mentioned in the dependent claims, a suitable development of the high-pressure pump indicated in claim 1 is possible.

  A high-pressure pump that controls the flow rate on the suction side using a metering unit in combination with a spring-loaded suction valve. If the pump speed is high, uniform supply is not guaranteed, and the pressure at the low pressure part For the above high-pressure pump, which has the disadvantage of generating noise due to pulsation, it is possible to reduce costs by omitting the metering unit, and even supply can be achieved even when the pump speed is high. Noise reduction can be achieved by preventing cavitation and pressure pulsations that can occur in

  In the conventional configuration, the suction strokes overlap particularly in the case of a multi-cylinder pump including three or more plungers. At that time, the pressure pulsation causes a particularly large difference in the pumping amount. This can be suitably prevented. In this case, it is possible to eliminate such a difference in the amount of upstream (vorgagert).

  In particular, in the case of a high-pressure pump configured as a single cylinder pump, a great cost advantage is generated. In the case of a two-cylinder pump configuration with a further separate actuator, the excess costs can be partially offset by the omission of holes in the housing of the high-pressure pump. The basic advantages of direct control are increased pump speed and improved high-pressure pump efficiency.

  Furthermore, by incorporating a suction valve in the cylinder head, a very small design size can be realized. The same is true for very large pressures, for example 300 MPa (3000 bar), which can be envisaged for commercial vehicle applications.

  Preferably, the suction valve is configured as an electromagnetically driven suction valve. Furthermore, the suction valve is advantageously fixed on the cylinder head by means of a set screw screwed into the cylinder head, which set screw is made of a ferromagnetic material. Thereby, the cap screw can function as a magnetic conductor, which increases the efficiency of the magnetic circuit and enables a high magnetic force.

  Furthermore, advantageously, a magnetic coil is provided, and the suction valve can be driven by energization of the magnetic coil, and the magnetic coil can be cooled by fuel that can be guided into the pump working chamber via the suction valve. Thus, cooling of the magnetic coil and other elements of the magnetic circuit can be achieved by the flow of fuel around it.

Preferably, the suction valve includes a valve body, a valve tappet acting against the sealing seat together with the valve body, the valve body is in contact with the cylinder head, provided with electromagnetically operable plunger type Amachaa The plunger-type armature lifts the valve tappet to open a seal seat formed between the valve body and the valve tappet during electromagnetic operation. In this way, a magnetic force for operating the suction valve can be generated via the plunger-type armature, in which case the set screw preferably functions as a magnetic conductor. In this case, the suction valve is suitably closed when the magnetic coil is turned off. When the magnetic coil of the magnet is energized and the pump plunger is at top dead center, for example, the suction valve is opened. During full filling, the suction valve is preferably opened until the pump plunger reaches bottom dead center. Here, more advantageously, an adjustment disk is provided which serves to set the working and residual gaps for the plunger-type armature. As a result, a modular configuration is possible, and it is possible to adapt to each application case of a high-pressure pump by incorporating an appropriate adjustment disk. This expands the application area of the high-pressure pump, in which case a simple adaptation of the high-pressure pump and almost the same configuration is possible.

  Preferably, a control is provided that drives the intake valve in accordance with the movement of the pump plunger of the pump assembly. On the one hand, advantageously, the control unit ends the drive time so that the suction valve is closed before the pump plunger reaches bottom dead center in order to reduce the filling of the pump assembly in the pump assembly. Shorten or extend the end of the drive time so that the suction valve is closed after the pump plunger reaches bottom dead center. Therefore, it is possible to shorten the drive time so that the suction valve is closed again before the pump plunger reaches the bottom dead center, thereby reducing the amount of fuel flowing into the pump working chamber. On the other hand, the intake valve is closed only after reaching bottom dead center, so that the fuel guided into the pump working chamber is partially transferred via the intake valve via the movement of the pump plunger. This can be achieved by sending it back in the opposite direction. In the first case, pressure pulsation on the low pressure side is reduced. In the second case, there is advantageously no void in the working barrel. Depending on the application, suitable variants can be specially selected. Yet another option is to reduce the beginning of the drive time so that the suction valve is opened only after the pump plunger has reached top dead center. Accordingly, since the suction valve is not opened immediately after the pump plunger reaches the top dead center, the amount of fuel flowing into the pump working chamber is similarly reduced. Here, an appropriate combination of drive modes by the control unit can also be performed. For example, the driving time can be shortened at the beginning and at the end. Therefore, the partial filling of the pump working chamber is preferably realized. Furthermore, a positive influence on the amplitude and frequency can be exerted on the pressure pulsation by means of one or more throttle valves connected upstream of the suction valve. Furthermore, it has a positive influence on the flow rate control. This can improve the noise behavior where pressure pulsations in the low pressure part can adversely affect.

Preferably, the suction valve is provided with a return seat spring having a high spring preload to achieve high rebound dynamics.

Preferred embodiments of the present invention will be described in detail in the following description with reference to the accompanying drawings.
FIG. 3 shows an excerpt of a schematic axial cross-sectional view of a high pressure pump, corresponding to an embodiment of the present invention.

  FIG. 1 shows an excerpt of a schematic axial sectional view of a high-pressure pump 1 corresponding to an embodiment of the present invention. The high-pressure pump 1 can be configured in particular as a radial plunger pump or an inline plunger pump. In particular, the high-pressure pump 1 is suitable as a fuel pump for a fuel injection device of an air compression type self-ignition internal combustion engine (luftverdichende, selbstzuendendenbrenncraftmachine).

  The high-pressure pump 1 is preferably used for a fuel injection device with a fuel distribution rail that stores diesel fuel under high pressure. However, the high-pressure pump 1 according to the present invention is also suitable for other application cases. In particular, the high-pressure pump can also be configured as a plunger pump that pumps other fluids as well, i.e. other fluids as fuel.

  The high-pressure pump 1 has a pump housing to which a cylinder head 2 is attached. The cylinder head 2 has a protrusion 3 that protrudes toward the inner cavity of the pump housing. Here, a barrel bore 4 is formed in the projection 3, and the pump plunger 5 of the pump assembly 6 is guided along the shaft 7 into the barrel bore 4.

  The high-pressure pump 1 further has a drive shaft 8 on which a cam 9 is provided. The cam 9 can here be configured as a multiple cam or as an eccentric part of the drive shaft 8. During driving, the drive shaft 8 rotates around the rotation shaft 10 together with the cam 9. Between the pump plunger 5 and the cam 9 of the pump assembly 6 there is an operative connection 11 indicated by a double arrow 11. For example, the operating force can be transmitted from the cam 9 to the pump plunger 5 via a roller shoe and a roller held in the roller shoe. The return movement of the pump plunger 5 can be effected via a suitable tappet spring.

  Thus, the pump assembly 6 can be driven by the cam 9 of the drive shaft 8. Depending on the configuration of the high-pressure pump 1, further further pump housings can be driven by the cam 9. Furthermore, a further cam can be provided on the drive shaft 8 to help drive another pump housing. Thus, according to the configuration, the high-pressure pump 1 configured as a radial plunger pump or an inline plunger pump can be realized.

  The pump plunger 5 defines a pump working chamber 12 within the barrel bore 4. A supply line 13 into which fuel is fed by a pre-feed pump serves as a fuel supply. A first throttle valve 14 and a second throttle valve 15 are provided in the supply pipeline 13. The supply line 13 leads to a low pressure chamber 16 formed by a recess 17 in the barrel head 2.

  The high pressure pump 1 has a suction valve 20. In this case, the low pressure chamber 16 is a component of the suction valve 20. The suction valve 20 is incorporated in the barrel head 2. Here, the suction valve 20 is arranged in the recess 17 of the cylinder head 2. At that time, the recess 17 is closed by a cap screw 21. In this way, the low pressure chamber 16 is also sealed from the outside. The holding screw 21 acts on the valve body 23 via the valve part 22. The holding screw 21 is screwed into the cylinder head 2, and thus presses the valve body 23 against the contact surface 24 formed on the cylinder head 2. Thereby, the holding screw 21 and the valve component 22 and the valve body 23 of the suction valve 20 are fixed so as not to move. Furthermore, the holding screw 21 and the valve component 22 are preferably formed of ferromagnetic material.

A valve tappet 25 is guided into the valve body 23. In this case, the valve tappet 25 acts on the seal seat (Dichtsitz) together with the valve seat surface 26 formed on the valve body 23. In this case, the valve spring 27 applies a force to the valve tappet 25 against the valve seat surface 26. In doing so, the valve spring 27 acts on the armature 30 via the valve element 28 and the adjusting disc 29. The armature 30 is configured as a plunger-type armature 30. The plunger-type armature 30 is connected to the valve tappet 25. Accordingly, a preload of the valve spring 27 is applied to the valve tappet 25. The valve tappet 25 of the suction valve 20, the valve element 28, the adjustment disk 29, and the plunger-type armature 30 are movable elements that are moved to open the suction valve 20 when the suction valve 20 is driven.

  The suction valve 20 further has a magnet 31 with a magnetic coil 32. The magnetic coil 32 is electrically connected to the pins 35 and 36 of the connector 37 via the conductive connection pins 33 and 34. Here, the connector 37 enables connection with the control device 38. The control device 38 functions as the control unit 38 in this embodiment. The control unit 38 may be incorporated in the central control device. The control device 38 is connected to a rotation angle sensor 39 that detects the current rotation angle of the drive shaft 8 and outputs it to the control device 38. A direct correlation with the current position of the pump plunger 5 occurs via the detected rotation angle. Thus, in particular, it can be detected whether the pump plunger 5 is at top dead center where the pump plunger 5 is at its maximum stroke and the pump working chamber 12 has a minimum volume. Correspondingly, it can be detected whether the pump plunger 5 is at the bottom dead center where the pump plunger has a minimum stroke and the volume of the pump working chamber 12 is maximum.

  A magnetic field is generated by energization of the electromagnetic coil 32. This magnetic field originates from the magnet 31 and can be amplified via the holding screw 21 having ferromagnetism. The magnetic circuit further returns to the cap screw 21 via the valve part 22 and the plunger-type armature 30 and possibly further further ferromagnetic elements. Here, a gap 40 is provided between the plunger-type armature 30 and the valve body 22. On the one hand, this gap 40 allows the movability of the plunger armature 30 and the position of the valve tappet 25 to be changed for the operation of the suction valve 20. On the other hand, at least a remaining gap is left as the gap 40 in order to prevent the electromagnetic adhesion effect of the plunger armature 30 to the valve part 22 in the activated state. In particular, when the electricity of the electromagnetic coil 32 is turned off, the suction valve 20 starts to be closed by the force of the valve spring 27 without delay. The maximum value of the gap 40 is set by the sum of the desired work gap and the remaining gap. Adjustment of the remaining gap and the working gap is possible by appropriate selection of the valve element 28 and the adjustment disc 29. In particular, a desired working gap can be set depending on the thickness of the adjustment disk 29. Accordingly, the thickness of the adjustment disk 29 sets the stroke of the valve tappet 25. If there is no change in the geometry in the region of the valve seat surface 26, the opening cross section of the valve seat surface 26 can be changed by the thickness of the adjusting disc, and thus the seal seat is opened. The possible flow rate into the pump working chamber 12 can also be adjusted. Thereby, adaptation of the suction valve 20 about each application case is possible.

  Therefore, the fuel can be guided from the low pressure chamber 16 to the pump working chamber 12 by operating the suction valve 20. In this case, the operation of the suction valve 20 is performed during the suction stroke of the pump plunger 5. During the delivery stroke of the pump plunger 5, the suction valve 20 is preferably closed. Thereby, the fuel under high pressure is pumped through the high-pressure line 42 via the outlet valve 41 that can be configured as a one-way valve or a check valve 41. The high-pressure line 42 is connected to, for example, a fuel distribution rail.

  A full filling of the pump working chamber 12 can be achieved, for example, when the suction valve 20 is opened at the top dead center of the pump plunger 5 and closed at the bottom dead center of the pump plunger 5. However, the suction valve 20 can be driven by the control unit 38 without depending on the stroke or the current position of the pump plunger 5 during the suction stroke. Thereby, partial filling of the pump working chamber 12 can also be realized. There are several options for this partial filling that can also be combined with each other.

  One option is to reduce the drive time of the suction valve 20 so that the suction valve 20 is closed again before the pump plunger 5 reaches bottom dead center. Alternatively, the drive time can be extended after reaching bottom dead center. In this case, since the suction valve 20 is closed only after the pump plunger 6 reaches the bottom dead center, a part of the fuel from the pump working chamber 12 is sucked in the reverse direction during the stroke of the pump plunger 5. Sent back through. Other fuel is pumped through the high pressure line 42. Thereby, the total amount of fuel pumped through the high-pressure line 42 for every pump stroke is reduced.

  Note that in this case, fuel is not sent back to the tank or the like. Furthermore, in this way, in some cases, noise behavior can also be improved by attenuation of pressure pulsations. In this case, adjustment is possible via the throttle valves 14 and 15.

  Yet another option for achieving partial filling is that the suction valve 20 is not opened immediately after the pump plunger 5 reaches top dead center. As a result, a certain return stroke of the pump plunger 5 is achieved, so that the total amount of fuel flowing into the pump working chamber 12 through the open cross section of the open seal seat is reduced.

  At the same time, the pressure pulsation can be reduced with regard to amplitude, frequency and flow control, preferably by means of one or more throttle valves 14, 15 or a damping volume chamber connected in front of the suction valve. Here, the throttle valve allows large partial reflections and small attenuations of compression waves and lean waves. Attenuating volume chambers allow for smaller partial reflections and stronger attenuation of compression and dilute waves. This depends on the geometric configuration of each attenuation volume chamber. A suction wave 20 or a compression wave configured to correspond to the suction valve 20 and possibly a plurality of suction valves being opened and closed and transmitted from the suction valve to a pressure pump, in particular an electric fuel pump, and reflected there. Lean waves are generated. The reflected wave may reappear, especially during the opening process of the suction valve 20, and may have an additional effect on the filling volume in the pump working chamber, which may cause high pressure pump supply fluctuations. There is. By adjusting the throttle valves 14 and 15 and the damping volume chamber in the supply line 13 and adjusting them, the compression wave is reduced to such an extent that uniform supply of the high-pressure pump 1 is ensured within a certain allowable range. I can do it. In doing so, the configuration and dimensions depend on the application area of the high-pressure pump 1 and the connection to the prefeed pump.

  Suitably, the suction valve 20 closed in the state which is not energized can be implement | achieved. The suction valve 20 is incorporated in the cylinder head 2. At this time, since the principle of the plunger-type armature is fully utilized, quick opening and closing of the suction valve 20 can be achieved. Furthermore, it is possible to provide a suction throttling in the working barrel where gas release is intentionally used. The required dynamics can be ensured by one or more connection holes. A sufficiently high recoil dynamics can be achieved through a correspondingly high spring preload of the valve spring 27. Cooling of the magnet 31 with the magnetic coil 32 can be achieved by the fuel flowing around it (Umspühling).

The invention is not limited to the described embodiments.

Claims (8)

A high pressure pump (1),
Comprising at least a cylinder head (2) and a pump assembly (6),
The cylinder head (2) has a barrel bore (4) into which the pump plunger (5) of the pump assembly (6) is guided,
The pump plunger (5) defines a pump working chamber (12) within the barrel bore (4);
An electromagnetically driven suction valve (20) incorporated in the cylinder head (2) and driven by a controller (38) according to the movement of the pump plunger (5) of the pump assembly (6) is provided;
Fuel can be guided to the pump working chamber (12) via the electromagnetically driven suction valve (20);
In order to guide the fuel to the pump working chamber (12) during the suction process, the pump is driven by driving the electromagnetically driven suction valve (20) delayed by the control unit (38). the plunger (5) the electromagnetically driven intake valve after reaching the top dead center (20) is opened, and pre-Symbol controller (38) the electromagnetically driven intake valve earlier end time of the driving time by (20) , The electromagnetically driven suction valve (20) is closed before the pump plunger (5) reaches bottom dead center,
The pump work chamber (12) can metering to reduce the loading of the fuel guided into the the Do Ri,
The electromagnetically driven suction valve (20) has a low pressure chamber (16), and is provided with a supply line (13) communicating with the low pressure chamber (16), and at least one of the supply line (13) is provided in the supply line (13). A high pressure pump (1) in which a throttle valve (14, 15) and / or at least one damping volume chamber is arranged .   The electromagnetically driven suction valve (20) is fixed on the cylinder head (2) by a set screw (21) screwed into the cylinder head (2), and the set screw (21) is made of a ferromagnetic material. The high-pressure pump according to claim 1, wherein the high-pressure pump is formed.   A magnetic coil (32) is provided, and the electromagnetic drive suction valve (20) can be driven by energization of the magnetic coil (32). The magnetic coil (32) is connected via the electromagnetic drive suction valve (20). The high-pressure pump according to claim 1, wherein the high-pressure pump can be cooled by a fuel that can be guided into the pump working chamber.   The electromagnetically driven suction valve (20) includes a valve body (23) and a valve tappet (25) that acts on a seal seat together with the valve body (23), and the valve body (23) A plunger-type armature (30) that abuts on the cylinder head (2) and can be electromagnetically operated is provided, and the plunger-type armature (30) is connected to the valve element (23) and the above-described valve during electromagnetic operation. The high-pressure pump according to any one of claims 1 to 3, characterized in that the valve tappet (25) is lifted to open the sealing seat formed between the valve tappet (25). .   5. The high-pressure pump according to claim 4, characterized in that an adjustment disk (29) is provided which serves to set a working clearance for the plunger-type armature (30). Before SL low-pressure chamber (16), the formed in the recess (17) of the electromagnetically driven intake valve (20) is disposed within the cylinder head (2), and the electromagnetically driven intake valve (20 pressing is closed by a screw (21), characterized and Turkey, high-pressure pump according to any one of claims 1 to 5).   The electromagnetically driven suction valve (20) has a return seat spring (27), and a preload of the return seat spring (27) is set. The high-pressure pump described.   The high-pressure pump according to any one of claims 1 to 7, which is a radial plunger pump or an in-line plunger pump for a fuel injection device of an air compression type self-ignition internal combustion engine.

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