DE102018212920A1 - piston pump - Google Patents

Abstract

The invention relates to a piston pump (1) with a pump piston (11), which can be moved back and forth in order to draw in a working medium into a pump work chamber (10) during operation of the piston pump (1) and to apply pressure in the pump work chamber (10) In order to improve the piston pump, in particular with regard to use as a high-pressure fuel pump, the piston pump (1) comprises an electromagnetic drive (12) with a magnetic device (14).

Description

The invention relates to a piston pump with a pump piston which can be moved back and forth in order to draw in a working medium into a pump work space during operation of the piston pump and to apply pressure in the pump work space. The piston pump is preferably a high-pressure fuel pump.

State of the art

From the German published application DE 10 2016 219 025 A1 A high-pressure fuel pump for a fuel injection system of an internal combustion engine is known, comprising a pump cylinder head with a cylinder bore in which a pump piston is accommodated in a stroke-movable manner, the pump piston delimiting an element space with fuel via an axially mounted suction valve, which comprises a valve piston opening into the element space can be filled.

Disclosure of the invention

The object of the invention is to improve a piston pump with a pump piston which can be moved back and forth in order to draw in a working medium into a pump work space during operation of the piston pump and to apply pressure in the pump work space, in particular with regard to use as a high-pressure fuel pump ,

The object is achieved in a piston pump with a pump piston which can be moved back and forth in order to draw in a working medium into a pump work space during operation of the piston pump and to apply pressure in the pump work space in that the piston pump comprises an electromagnetic drive with a magnetic device , The working medium is preferably fuel to which high pressure is applied by the piston pump in the working space. The working medium, in particular the fuel, is drawn into the pump work space via a suction valve. When the working medium is sucked in, the pump piston moves in a first direction. After priming, the pump piston is moved in a second direction that is opposite to the first direction. As a result, the working medium located in the pump work space is subjected to pressure, in particular high pressure. Modern common-rail high-pressure injection pumps are based on the piston engine principle. A linearly reciprocating high-pressure piston sucks in the fuel via the suction valve, compresses it and then feeds it further into the rail via a check valve. A rotary movement of the camshaft and the roller is converted into a linear movement of the high-pressure piston. There are different forms of such drives. It can be implemented, for example, by rolling a roller on a camshaft as with a CP4 pump or by sliding a cup on an eccentric shaft as with a CP1H. In both cases, an engine converts a rotational movement into a translatory movement. The named engine, which is responsible for converting the movement types, must be supplied with lubricant. Either diesel fuel or engine oil is used as the lubricant. The robustness of such a tribological system depends very much on the quality of the lubricant. Since the products are sold to different countries, the quality of the lubricants can fluctuate greatly. Furthermore, such a system is usually driven directly by the engine via a crankshaft, a camshaft or a balancer shaft, which means that sufficient installation space must be made available in the engine compartment. This flexibility of free installation space is often lacking and you live with the consequences, such as long high-pressure lines or additional attachments. High belt forces / chain forces that are unavoidable in today's designs also have a negative effect on the engine. Furthermore, with conventional piston pumps of the previous solution, an interface to the customer is necessary, since these pumps are driven directly by the motor. Another disadvantage compared to the idea described here is not only the packaging requirements in the engine compartment but also the weight of today's pumps. Furthermore, conventional pumps, for example via the chain and belt drive, are usually also driven when the injection system does not require high-pressure quantities - for example, in pure overrun mode. This creates friction loss and pumping losses. In addition, noises are generated by the operation of the high-pressure pump, even during overrun. The claimed piston pump provides a new concept of high-pressure generation, in which the translatory movement of the pump piston is no longer realized via the roller-cam concept, but directly via the magnet device. Among other things, this provides the following advantages: robust against poor fuel quality; Motor speed independence, that means no mandatory mechanical connection / translation to the motor; Injection synchronism or injection asynchrony possible; reduced packaging requirements in the engine compartment; in particular additionally increased flexibility of the positioning in the engine compartment, for example directly on a high pressure accumulator, which is also referred to as a high pressure rail; reduced weight; Zero funding possible; Stroke variation possible; Efficiency, in particular through precise control of the magnetic device, in particular an electromagnet; inexpensive, because in particular classic components such as flange, shaft sealing ring, drive shaft, bearing of the drive shaft, possibly polygon rings and other drive parts of conventional high-pressure pumps, for example a tappet assembly, are omitted; if necessary in the case of a pressure control valve on the high pressure rail; since the coupling to the belt or chain drive of the motor is omitted, it can be designed in a simpler, lighter and more cost-effective manner, since today's single-ram pumps with roller double-cam drive generate very large and dynamic drive forces and drive vibrations; Elimination of an interface belt, sprocket, gear on the motor; no power consumption in overrun mode; Reduction of noise emissions compared to high-pressure pumps with conventional engines; Reduction of the risk of particles by eliminating the engine; Due to the existing magnetic field, suitable structural measures can also be used to collect metallic particles / residual dirt in the piston pump and thus do not reach the other system components.

A preferred exemplary embodiment of the piston pump is characterized in that the magnet device comprises a holding magnet with a magnetic core and with at least one coil and a central receiving space for the pump piston. This provides an efficient electromagnetic drive for the piston pump.

Another preferred exemplary embodiment of the piston pump is characterized in that an armature of the magnet device is attached to one end of the pump piston. The armature is preferably attached to an end of the pump piston protruding from the central receiving space. In addition to the armature, the magnet device, in particular the holding magnet, comprises at least one coil and a magnetic core. The function of the pump piston is advantageously performed by the armature, which is connected to the pump piston. The high pressure is generated by driving an electromagnet and building up a magnetic field. The armature and the pump piston are set in motion by the magnetic field. The armature is then returned together with the pump piston by timely switching off the coil current and by an optional brake and / or return spring or return spring.

Another preferred embodiment of the piston pump is characterized in that the armature is biased into a starting position by a brake and / or return spring. This ensures proper operation of the piston pump in a simple manner.

Another preferred exemplary embodiment of the piston pump is characterized in that the armature is guided over the pump piston. Among other things, this provides the advantage that further measures for guiding the anchor can be dispensed with.

Another preferred exemplary embodiment of the piston pump is characterized in that the armature is guided on an outer circumference. The armature is guided, for example, with an outer circumference in a housing body of the piston pump. The anchor can be placed in a wet or dry environment. If the armature is arranged in a dry environment, then one or the central receiving space for the pump piston is advantageously connected to a low pressure return. If the armature is arranged in a wet environment, then a receiving space for the armature is advantageously connected to a low pressure return. In connection with the surroundings of the armature, dry means that no working medium, such as fuel, is arranged in the surroundings of the armature. Analogously, wet means that working medium, in particular fuel, is present in the vicinity of the armature.

Another preferred exemplary embodiment of the piston pump is characterized in that the magnet device comprises a plurality of coils in order to represent a division of magnetic force. The coils can advantageously be controlled centrally in order to represent different magnetic forces. Among other things, this has the advantage that the piston pump works as efficiently as possible with different high pressure requirements. In this way, a coil with a smaller magnetic force can be controlled at lower pressures. At higher pressures, at least one additional coil can be energized.

Another preferred exemplary embodiment of the piston pump is characterized in that the piston pump is designed as a double-piston pump with a common armature. As a result, the delivery rate of the piston pump can be increased in a simple manner.

Another preferred exemplary embodiment of the piston pump is characterized in that the piston pump is designed as a series piston pump with two armatures. Depending on the control, the working medium can be pumped in phase or out of phase with the in-line piston pump.

Another preferred exemplary embodiment of the piston pump is characterized in that the piston pump has two double-piston pumps arranged in series, each with one common anchor includes. A quadruple pump can thus be represented in a simple manner.

The invention optionally also relates to a method for operating a piston pump described above.

The invention optionally also relates to a pump piston, an armature, a brake and / or return spring and / or a magnetic device, in particular a holding magnet, for a piston pump described above. The parts mentioned can optionally be traded separately.

Further advantages, features and details of the invention emerge from the following description, in which various exemplary embodiments are described in detail with reference to the drawing.

list of figures

• 1 eine schematische Darstellung einer als Kraftstoffhochdruckpumpe ausgeführten Kolbenpumpe mit einem elektromagnetischen Antrieb im Schnitt;
• 2 eine vereinfachte perspektivische Darstellung der Kolbenpumpe aus 1:
• 3 die Kolbenpumpe aus 2 im Längsschnitt;
• 4 eine ähnliche Kolbenpumpe wie in 3, wobei ein Anker des elektromagnetischen Antriebs in einer trockenen Umgebung angeordnet ist;
• 5 die gleiche Darstellung wie in 4, wobei der Anker in einer nassen Umgebung angeordnet ist;
• 6 eine ähnliche Kolbenpumpe wie in 3 mit einem elektromagnetischen Antrieb, der eine Magneteinrichtung mit drei Spulen umfasst;
• 7 eine als Doppelkolbenpumpe ausgeführte Kolbenpumpe mit einem Anker, der in einer trockenen Umgebung angeordnet ist;
• 8 eine ähnliche Darstellung wie in 7, wobei der Anker in einer nassen Umgebung angeordnet ist;
• 9 die Doppelkolbenpumpe aus den 7 und 8, wobei der Anker einen Hub nach oben ausgeführt hat;
• 10 die Doppelkolbenpumpe aus 9, wobei der Anker einen Hub nach unten ausgeführt hat;
• 11 eine als Reihenkolbenpumpe ausgeführte Kolbenpumpe im Schnitt;
• 12 die Reihenkolbenpumpe aus 11 in einer perspektivischen Darstellung;
• 13 die Reihenkolbenpumpe aus 11, wobei ein linker Anker einen Hub nach unten ausgeführt hat;
• 14 die Reihenkolbenpumpe aus 13, wobei ein rechter Anker einen Hub nach unten ausgeführt hat;
• 15 die Reihenkolbenpumpe aus 11 bei einer phasengleichen Förderung; und
• 16 eine perspektivische Darstellung einer Vierfachpumpe, die zwei in Reihe angeordnete Doppelkolbenpumpen umfasst.

Show it:

• 1 a schematic representation of a piston pump designed as a high-pressure fuel pump with an electromagnetic drive in section;
• 2 a simplified perspective view of the piston pump 1 :
• 3 the piston pump 2 in longitudinal section;
• 4 a similar piston pump as in 3 , wherein an armature of the electromagnetic drive is arranged in a dry environment;
• 5 the same representation as in 4 wherein the anchor is placed in a wet environment;
• 6 a similar piston pump as in 3 with an electromagnetic drive comprising a magnetic device with three coils;
• 7 a piston pump designed as a double piston pump with an armature, which is arranged in a dry environment;
• 8th a representation similar to that in 7 wherein the anchor is placed in a wet environment;
• 9 the double piston pump from the 7 and 8th , wherein the anchor has performed an upward stroke;
• 10 the double piston pump 9 , wherein the anchor has made a stroke down;
• 11 a piston pump designed as a linear piston pump in section;
• 12 the inline piston pump 11 in a perspective view;
• 13 the inline piston pump 11 , with a left anchor making a downward stroke;
• 14 the inline piston pump 13 , with a right armature making a downward stroke;
• 15 the inline piston pump 11 with in-phase funding; and
• 16 a perspective view of a quadruple pump, which comprises two double-piston pumps arranged in series.

Description of the embodiments

In the 1 to 16 are different embodiments of a piston pump 1 shown in different views and states.

The in the 1 to 3 piston pump shown 1 is as a high pressure fuel pump 2 with a pump housing 3 executed, essentially only through a pump inlet 4 and a pump outlet 5 is indicated. The pump inlet 4 includes a low pressure inlet 6 with a suction valve 7 , The pump outlet 5 includes a high pressure connection 8th with a check valve 9 ,

Via the pump inlet 4 is in operation of the piston pump 1 a working medium, in particular fuel, in a pump work space 10 sucked in by a pump piston 11 is limited. The pump piston 11 is also referred to as a high pressure piston because it is in the pump workspace 10 Working medium sucked in through the pump piston 11 is pressurized with high pressure. The high-pressure working medium is then fed through a check valve 9 conveyed to a high-pressure fuel reservoir of a fuel injection system, for example. The pump piston guides when working medium is sucked in 11 a move in 1 down in the vertical direction. When pressurizing the working medium in the work area 10 the pump piston leads 11 in 1 a vertical upward movement.

The reciprocation of the pump piston 11 is different from conventional high-pressure fuel pumps by an electromagnetic drive 12 initiated. For this purpose the pump piston is 11 in a central recording room 13 a magnetic device 14 arranged. The central recording room 13 is essentially designed as a high pressure bore. At the top of the central recording room 13 is the work space 10 arranged. The magnetic device 14 is as a magnet 15 executed.

The magnet 15 is also called a pot magnet and includes a magnetic core 16 with a coil 17 , In addition, the magnet device includes 14 an anchor 18 , The anchor 18 is on one of the central recording room 13 the magnetic device 14 protruding end of the pump piston 11 attached. By dashed lines with arrowheads is in 1 a magnetic field 19 indicated that arises when the coil 17 the magnetic device 14 is energized. The magnetic device 14 with the magnetic core 16 and the coil 17 represents one as a holding magnet 15 executed electromagnets.

Through the magnetic field 19 becomes the anchor 18 together with the pump piston 11 to represent the electromagnetic drive 12 set in motion. By switching off the coil current as well as an optional return spring, the pump piston becomes 11 with the anchor 18 brought back again.

The pump piston 11 is, for example, in the anchor designed as an anchor plate 18 pressed. Alternatively or additionally, the pump piston can 11 welded or otherwise non-positively to the anchor 18 be connected. Alternatively, the anchor 18 and the pump piston 11 be made from one piece.

The choice of materials plays with regard to the function of the electromagnetic drive 12 with the magnetic device 14 an important role. To the magnetic field 19 optimal use and a maximum force on the pump piston 11 to be able to generate, are used to represent the anchor 18 advantageously used ferromagnetic materials.

The anchor 18 and the pump piston 11 can also be formed from a ceramic material. Among other things, the ceramic material provides the advantage of a smaller moving mass. Depending on the version, the anchor can 18 also from the pump piston 11 be decoupled. In this case the anchor would have to 18 be performed separately. In the illustrated embodiment, the anchor 18 advantageous due to the pump piston 11 guided. In addition to the materials, there is also a minimum thickness of the anchor 18 for an optimal design of the electromagnetic drive 12 required.

The magnetic core 16 advantageously takes over the function of a cylinder head and a housing at the same time. Even with the magnetic core 16 it is important to use the optimal material. Similar to the anchor 18 are also used to represent the magnetic core 16 advantageously used ferromagnetic materials. Because in the central recording room 13 in the magnetic core 16 at the same time the high pressure generation of the piston pump 1 takes place, the magnetic core 16 additionally be formed from a high pressure pulse resistant material.

Depending on the application, especially in applications that require large electromagnetic forces, the coil can 17 be subjected to high thermal loads. The thermal load can lead to conventional copper wire coils reaching their application limits. Special wall coils that can withstand greater thermal loads can advantageously be used here.

The windings of such coils consist, for example, of aluminum strips with a special coating. Due to the very high thermal conductivity of the coated aluminum strips, undesirable heat build-up, as can occur with copper wire coils that are provided with a lacquer, can be avoided. The special coils also advantageously have a low weight. Due to the very thin width of the aluminum strips, many windings can be accommodated with a small size, which leads to an increase in the magnetic force.

The stroke of the anchor 18 and thus the pump piston 11 can advantageously be varied by, for example, storing a current profile as a function of current over a defined period of time for the coil energization. Through the electromagnetic drive 12 classic low-pressure flow control, such as a metering unit or an electric suction valve, is advantageously not required to display high-pressure flow control. As a result, both injection synchronism and injection asynchrony are possible at all load points / speeds.

If required, high-pressure volume control can also be implemented with classic low-pressure volume control.

In the 4 and 5 Two possible principles for leakage drainage are shown. In 4 is the anchor 18 in a housing body 22 in a dry environment 23 arranged. For sealing against the pump work area 10 is the pump piston 11 a rod seal 24 assigned. Above the rod seal 24 is a low pressure duct 25 a low pressure return 26 arranged, which is indicated by an arrow. The anchor 18 is a brake and / or return spring 27 assigned. The brake and / or return spring 27 is on the magnetic core 16 attached outside. Via the low pressure channel 25 who, for example, as Additional hole is made, the leakage is advantageous directly in front of the rod seal 24 dissipated.

In 5 is the anchor 18 in a housing body 28 in a wet environment 29 arranged. The leakage is in the housing body 28 collected and via a return 30 dissipated, which is indicated by an arrow.

The braking and return of the anchor 18 can by switching off the coil current as well as by the brake and / or return spring 27 will be realized. The brake and / or return spring 27 can, as shown, on the outside of the magnetic core 16 be arranged. Alternatively or additionally, the or a further brake and / or return spring can also be centered on the pump piston 11 to be appropriate. Optionally, the anchor can 18 can also be equipped with a tension spring for resetting.

In 6 it is shown that the magnetic device 14 also more than one coil, in the illustrated embodiment three coils 31 . 32 and 33 , may include. With the coils 31 to 33 different magnetic forces can be represented. In addition, the coils 31 to 33 can be controlled individually. This has the advantage that the piston pump works as efficiently as possible with different high pressure requirements.

In this way, a coil with low magnetic force can be controlled at low pressures. At higher pressures, at least one additional coil can be activated. This is also to overcome an air gap between the anchor 18 and the magnetic core 16 an advantage, especially with larger armature strokes, since a larger magnetic force is required with a larger air gap. With a movement of the anchor 18 in 6 upwards the air gap becomes smaller, so that the complete magnetic force is no longer necessary to achieve a desired pressure in the pump work space 10 to create. As a result, individual coils can then be switched off.

In the 7 to 10 is shown that the piston pump 1 also as a double piston pump 40 with two magnetic devices 41 . 42 and a common anchor 43 can be executed. The two magnetic devices 41 . 42 are designed or similar to the magnetic device 14 in the 1 to 5 , On the common anchor 43 is a common pump piston 44 attached. The opposite ends of the common pump piston 44 the double piston pump 40 each limit a pump work space 38 . 39 ,

By installing two coils 61 . 62 in the magnetic devices 41 . 42 can be used on springs to brake or return the pump piston 44 to be dispensed with. The spools 61 . 62 are in operation of the double piston pump 40 alternately switched off or on at the right time.

In 7 is shown that the anchor 43 in a dry environment 46 in a housing body 45 can be arranged. Low-pressure ducts extend to discharge leakage 47 . 49 each to a low pressure return 48 . 50 , The pump work room 38 is a pump inlet 51 and a pump outlet 53 assigned. The pump work room 39 is a pump inlet 52 and a pump outlet 54 assigned.

In 8th is shown that the anchor 43 also in a housing body 55 in a wet environment 56 can be arranged. The housing body 55 is with a low pressure return 57 fitted.

In 9 is by a lightning symbol 63 energizing the coil 61 indicated. With arrows 64 is in 9 indicated that the anchor 43 when energizing the coil 61 is moved upwards. With an arrow 59 is indicated that by the corresponding movement of the pump piston 44 top working medium in the pump work space 39 is sucked in. At the same time in the pump work room 38 located working medium with high pressure and, as by an arrow 60 is indicated at the pump outlet 53 pushed out.

In 10 is by a lightning symbol 65 hinted that the coil 62 is energized. With arrows 66 is indicated that the anchor 43 when energizing the coil 62 moved down. Here, as in 10 by an arrow 67 is indicated, working medium via the pump inlet 51 in the pump work room 38 sucked. At the same time, in the work room 39 working medium is compressed and, as by an arrow 68 in 10 is indicated via the pump outlet 54 pushed out.

In the 11 to 15 is an in-line piston pump 70 executed piston pump 1 shown. The inline piston pump 70 comprises two magnetic devices 71 . 72 , The magnetic devices 71 and 72 are designed or similar to the magnetic device 14 in the 1 to 5 , The inline piston pump 70 includes two anchors 73 . 74 that can be moved separately or together. On the anchor 73 is a pump piston 75 attached. On the anchor 74 is a pump piston 76 attached.

The anchors 73 . 74 are about coils 77 . 78 actuated. The anchors 73 . 74 are brake and / or return springs 79 . 80 assigned. The pump piston 75 limits a pump work space 86 , The pump pistons 76 limits a pump work space 87 , The inline piston pump 70 includes two pump inputs 81 . 82 and two pump outlets 83 . 84 , In 12 you can see that the inline piston pump 70 a common electrical connection 85 for the two magnetic devices 71 and 72 having.

The anchors 73 . 74 and the pump pistons 75 . 76 are with the inline piston pump 70 arranged in a row in a manner similar to that of an in-line engine. In the 13 and 14 is a phase-shifted delivery with the in-line piston pump 70 illustrated. In 13 is by a lightning symbol 88 and by arrows 89 illustrates that the anchor 74 when energizing the coil 78 moved up. The working medium becomes in the pump work space 87 pressurized and as by an arrow 90 is indicated via the pump outlet 84 pushed out. At the same time, the restoring effect of the brake and / or return springs 79 causes like an arrow 91 is indicated, working medium via the pump inlet 81 in the pump work room 86 sucked.

In 14 is by a lightning symbol 95 and by arrows 96 indicated that when energizing the coil 77 the anchor 73 is moved upwards. Doing so in the work room 86 located working medium with high pressure and, as by an arrow 57 is indicated via the pump outlet 83 pushed out. At the same time, the restoring effect of the brake and / or return spring 80 the anchor 74 with the pump piston 76 moved down. Here, like an arrow 93 is indicated, via the pump inlet 82 Working medium in the pump work room 87 sucked.

In 15 is by lightning symbols 101 . 102 indicated that the two coils 77 . 78 can also be energized simultaneously to the anchor 73 . 74 with the pump pistons 75 . 76 to move up at the same time. Here, as with arrows 103 and 104 in 15 is indicated, at the same time working medium in the pump work rooms 86 . 87 pressurized and via the pump outlets 83 . 84 pushed out.

In 16 is a quadruple pump 110 shown in perspective. In the quadruple pump 110 are two double piston pumps 111 . 112 each with a common anchor 113 . 114 arranged in a row. The common anchors 113 . 114 are two pump pistons each 115 . 116 and 117 assigned.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for better information for the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016219025 A1 [0002]

Claims (10)

Piston pump (1) with a pump piston (11; 44; 75.76; 115-117), which can be moved back and forth in order to operate a working medium into a pump work chamber (10; 38,39; 86, 87) and to apply pressure in the pump work space (10; 38,39; 86,87), characterized in that the piston pump (1) has an electromagnetic drive (12) with a magnetic device (14; 41,42; 71, 72). Piston pump after Claim 1 , characterized in that the magnetic device (14; 41.42; 71.72) a holding magnet (15) with a magnetic core (16) and with at least one coil (17; 31-33; 61.62; 77.78) and comprises a central receiving space (13) for the pump piston (11; 44; 75.76; 115-117). Piston pump after Claim 2 , characterized in that an armature (18; 43; 73.74; 113.114) of the magnet device (14; 41.42; 71.72) is attached to one end of the pump piston (11; 44; 75.76; 115-117) is. Piston pump after Claim 3 , characterized in that the armature (18; 43; 73,74; 113,114) is biased into a starting position by a brake and / or return spring (27; 79,80). Piston pump after Claim 4 , characterized in that the armature (18; 43; 73.74; 113.114) is guided over the pump piston (11; 44; 75.76; 115-117). Piston pump after Claim 4 or 5 , characterized in that the armature (18; 43; 73.74; 113.114) is guided on an outer circumference. Piston pump according to one of the preceding claims, characterized in that the magnetic device (14) comprises a plurality of coils (31-33) in order to represent a magnetic force distribution. Piston pump according to one of the preceding claims, characterized in that the piston pump (1) is designed as a double-piston pump (40) with a common armature (43). Piston pump according to one of the Claims 1 to 7 , characterized in that the piston pump (1) is designed as a series piston pump (70) with two armatures (73, 74). Piston pump according to one of the Claims 1 to 7 , characterized in that the piston pump (1) comprises two double-piston pumps (111, 112) arranged in series, each with a common armature (113, 114).

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