DE102008040833A1 - Fuel conveyor for an internal combustion engine - Google Patents

Abstract

A fuel delivery device (14) for an internal combustion engine comprises a housing (12), at least one delivery module (18) plugged into a corresponding receiving opening (86) in the housing (12), and one mounted in the housing (12) Drive shaft (52) for the delivery module (18). Furthermore, a prefeed pump (16) is provided, the outlet of which is connected to an inlet of the conveyor module (18). It is proposed that a drive shaft (52) of the prefeed pump (16) is coupled to or integral with the drive shaft (52) for the delivery module (18).

Description

State of the art

The The invention relates to a fuel delivery device for an internal combustion engine according to the preamble of claim 1.

From the DE 103 22 604 A1 a fuel delivery device is known in which a prefeed pump sucks the fuel from a fuel tank and compressed to a comparatively low Vorförderdruck. From the prefeed pump, the fuel is conveyed to a high-pressure piston pump, which comprises a delivery module, which is inserted into a receiving opening in a housing of the high-pressure pump. To the delivery module includes an inlet port, an outlet port, a delivery piston, etc. In the housing of the high-pressure pump, a drive shaft is mounted with a drive cam, which works together with the piston of the delivery module. The delivery module conveys the fuel into a common rail, to which injectors are connected, which inject the fuel directly into combustion chambers.

Disclosure of the invention

task The present invention is to be as compact as possible Fuel conveyor to create over it can also be inexpensively manufactured and assembled.

These Task is accompanied by a fuel conveyor the features of claim 1 solved. Advantageous developments are given in subclaims. Furthermore find for the invention important features in the subsequent description and in the drawing, wherein the features both alone and in different combinations may be important to the invention without This is again explicitly pointed out.

By the coupling of the drive shaft of the feed pump with the Drive shaft for the conveyor module is a for the prefeed pump and the delivery module together Drive created, whereby space is saved, resulting in a overall compact fuel conveyor leads. In addition, additional can also Components, such as bearings, gears, separate drives, etc. be saved what the manufacturing costs and effort in the Assembly reduced.

advantageously, is the drive shaft of the feed pump by an end portion formed the drive shaft for the delivery module. This eliminates both coupling and a possible connecting gear, which further enhances the compactness and lowers costs.

A Gear pump is very robust as a feed pump, in particular an external gear pump.

One fluid-tight connected to a housing body Housing cover of the gear pump makes additional Seals dispensable.

Especially It is advantageous to carry out the prefeed pump in such a way that that they are attached directly to an engine case, for example, can be flanged, as this also additional fasteners can be omitted and the prefeed pump spatially close to the delivery module, which is plugged into the engine casing, is arranged. This comes the compactness of the invention Fuel conveyor benefit. Alternatively, the Front pump even be integrated into the engine casing, whereby the number of projecting from the engine housing Parts reduced and thus, for example, the accessibility less restricted to other components of the internal combustion engine becomes.

Of the Area of the engine housing, in or on the arranged the delivery module and the feed pump can be a total fuel-filled area, the opposite of a lubricant-filled area the engine housing is sealed. Delivery module and / or Pre-feed pump run so to speak "in the fuel", whereby these are cooled and lubricated and additional Seals are no longer necessary. This will increase the efficiency of the Fuel conveyor improves at the same time simplified structure.

A inexpensive possibility for the realization of the seal between fuel-filled area and lubricant-filled area Range consists in the use of a shaft seal, which with the preferably common drive shaft for delivery module and pre-feed pump cooperates. The sealing effect can be improved, in which two adjacent and spaced apart Shaft seals are used, between which an annular space is formed of which a discharge channel for the discharge of leakage fluid branches.

Additional assembly of hose connections are avoided if fluid connections between the feed pump and delivery module are integrated into the engine housing. This applies, in particular, to a channel which connects an outlet of the prefeed pump to an inlet of the conveyor module, and to a channel which has an inlet of the prefeed pump with a tank inlet connection connects.

to Adjustment of funded by the fuel conveyor Fuel quantities can be used a quantity control body, which arranged fluidically between pre-feed pump and delivery module is. In particular, when it comes to the quantity control body a suction throttle is, this can with the pre-feed pump be connected, preferably in the housing of the feed pump be plugged. This will allow pre-assembly, which reduces production costs. In addition, the maintenance simplified by the modular design.

Point Pre-feed pump and delivery module a common Drive shaft on, can between feed pump and delivery module on the drive shaft a shaft seal for sealing between the delivery module and prefeed pump be arranged. This then ensures safe operation of the fuel delivery device, if the drive shaft in the area of the conveyor module in the lubricant-filled area the internal combustion engine housing is arranged.

A Easy maintenance is possible when the pre-feed pump a housing with a tank-side inlet nozzle and / or has delivery module side outlet. Furthermore This makes the selection of the suitable prefeed pumps possible increased, since these are not attached to the burner housing need to be adjusted, but via separate lines can be connected to the conveyor module.

following Be embodiments of the invention with reference explained in the accompanying drawings. In the drawing demonstrate:

1 a schematic perspective view of an internal combustion engine with a prefeed pump and a delivery module;

2 a partial section through the arrangement of 1 ; and

3 a representation similar 2 an alternative embodiment.

1 shows a diesel internal combustion engine 10 , which is installed in a motor vehicle, not shown. It comprises an internal combustion engine housing 12 and a fuel conveyor 14 , which is a prefeed pump 16 and a high pressure delivery module 18 includes. The pre-feed pump 16 includes a priming pump housing 20 , in the front side of an inlet nozzle 22 plugged or screwed, the via a line 24 with a fuel tank 26 connected is. In a radial opening of the prefeed housing 20 is a quantity control member in the form of an electromagnetically actuated suction throttle 27 plugged in. The high-pressure conveyor module 18 includes a module housing 28 and an outlet 30 that has a high pressure line 32 with a common rail 34 connected is. At the latter are several injectors 36 connected, the fuel directly into them associated combustion chambers (not shown) of the internal combustion engine 10 inject. An outlet 38 on the pre-feed pump 16 leads over a connecting line 40 to an inlet nozzle 42 of the high pressure delivery module 18 ,

In 2 is the prefeed pump 16 shown in great detail. It includes a first and partially hollow bearing pin 44 that is integral with a housing body 45 of the pre-supply pump housing 20 is formed and on which a driven gear 46 the prefeed pump designed as an external gear pump 16 is rotatably mounted. The driven gear 46 is about a coupling piece 48 with a front end pin 50 a balance shaft 52 the internal combustion engine 10 rotatably connected. The balance shaft 52 the internal combustion engine 10 in this respect forms a drive shaft of the prefeed pump 16 ,

A revolving gear 54 is on a second and also partially hollow journal 56 rotatably mounted and combs in a Kämmbereicht 58 with the driven gear 46 , The inlet nozzle 22 is over at least partially outside the cutting plane of 2 lying connection channel 60 in the priming pump housing 20 with one also outside the cutting plane of 2 lying and not shown inlet area of the two gears 46 and 54 connected.

From a drainage area of the two gears 46 and 54 leads also outside the cutting plane of 2 lying channel 62 to the suction throttle 27 , One recognizes that these in a stepped bore 64 in the priming pump housing 20 is inserted or screwed. The suction throttle 27 , which is also referred to as "metering unit", is therefore in the feed pump 16 integrated. From the stepped bore 64 leads a channel 66 to the outlet 38 ,

One recognizes 2 in that the priming pump housing 20 from the housing body 45 and a housing cover 70 consists. The housing cover 70 is opposite the housing body 68 through an O-ring 72 sealed. In the housing cover 70 is a passage opening 74 present, through which the stepped end pin 50 the balance shaft 52 from the engine case 12 out into the priming pump housing 20 extends into it. Between the passage opening 74 and the end pin 50 the balance shaft 52 is a first shaft seal 76 arranged. A second shaft seal 78 seals the balance shaft 52 opposite the engine casing 12 from. An O-ring 80 in turn seals the housing cover 70 opposite the engine casing 12 from. The pre-feed pump 16 is via an annular mounting flange 82 and an intermediate ring 84 outside the engine housing 12 screwed.

Although not shown in figure, the balance shaft is used 52 also for driving the high-pressure conveyor module 18 , The structural design may correspond to those which are described below in connection with the in 3 illustrated embodiment will be explained.

The in the 1 and 2 shown fuel conveyor 14 works as follows: with a rotation of the balance shaft 52 are also the two gears 46 and 54 set in rotation, causing fuel from the fuel tank 26 to the inlet nozzle 22 sucked and to the outlet 38 is transported. From there, the fuel reaches the inlet port with a slightly higher pressure 42 of the high pressure delivery module 18 where it is compressed to a high pressure and over the outlet 30 to the common rail 34 is encouraged.

Now, an alternative embodiment with reference to 3 explained. It applies to 3 that such elements and areas in 3 which have equivalent functions to elements and areas already associated with the 1 and 2 have been explained, bear the same reference numerals and will not be discussed again in detail.

In the in 3 shown sectional view is a receiving opening 86 in the engine housing 12 recognizable, in which the high-pressure conveyor module 18 is plugged in. Attached is the high-pressure conveyor module 18 on the engine housing 12 through a flange 88 using screws, as in 1 is apparent. To the high-pressure conveyor module 18 heard a piston sleeve 90 in which a delivery piston 92 is guided in a sliding manner. This in 3 shown lower end of the delivery piston 92 lies on a shoe 94 in which a role 96 is guided. This rolls on the outer shell of a cam 98 on the balance shaft 52 is trained. To the high-pressure conveyor module 18 also includes a pen 100 that with the shoe 94 is connected and to which a piston spring 102 supported. Not shown, but still part of the high-pressure conveyor module 18 are a delivery room, which has an outlet valve with the outlet 30 ( 1 ) is connectable. The supply of fuel to the pumping chamber via a likewise not shown inlet valve.

The balance shaft 52 is on both sides of the cam 98 opposite the engine casing 12 through shaft bearings 104 stored. Unlike the in 2 the embodiment shown is the balance shaft 52 not between engine casings 12 and pre-feed pump 16 but in 3 to the left of the cam 98 about shaft seals 76 and 78 sealed. Between the shaft seals 76 and 78 is an annulus 104 present, via a discharge channel 106 For example, connected to a leakage connection. The lubrication of the in 3 left camp 104 done by one in the balance shaft 52 running channel 108 ,

The connection to the fuel tank 26 takes place by a connection, not shown, on the engine housing 12 , This connection is with a room 110 connected between the cam 98 , Balance shaft 52 and engine casings 12 is formed. From this room 110 leads out of the cutting plane of 3 lying inlet channel 60 that is in the engine housing 12 is formed, to the inlet side of the combing area 58 the two gears 46 and 54 , A likewise in the engine housing 12 trained and also outside the cutting plane of 3 lying channel 40 connects the outlet side of the combing area 58 the two gears 46 and 54 with the intake valve, not shown, of the high-pressure delivery module 18 ,

In the 3 shown fuel conveyor 14 works similar to those of the 1 and 2 : you recognize it 3 even more accurate, that upon rotation of the balance shaft 52 the delivery piston 92 is set in a reciprocating motion, whereby by the pre-feed pump 16 pre-compressed fuel further compressed and to the common rail 34 is encouraged. Unlike the embodiment of the 1 and 2 The fuel flows through on its way to the pre-feed pump 16 the room 110 and thereby ensures cooling and lubrication of the existing components there. The high-pressure conveyor module 18 runs almost "in the fuel". At the room 110 So it is a "fuel - filled area", whereas in 3 to the left of the two shaft seals 76 and 78 arranged region can be regarded as a lubricant-filled area. The seal between these two areas is through the two shaft seals 76 and 78 accomplished. In addition, the fluid transport is carried out by the prefeed pump 16 to the high-pressure conveyor module 18 by the in the engine housing 12 trained channel 40 and not by an outside of the engine case 12 arranged connection line.

In an embodiment, not shown Form the prefeed pump housing is integrated into the engine housing. Also possible, but not shown, is the use of a prefeed pump with an integrated quantity control element, for example a suction throttle, independently of the use of a high-pressure conveying module or a common or at least coupled drive shaft. It is also conceivable that not a balancing shaft of the internal combustion engine, but a separate drive shaft is used as a drive for both the high-pressure conveyor module and for the prefeed pump.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10322604 A1 [0002]

Claims (15)

Fuel conveyor ( 14 ) for an internal combustion engine having a housing ( 12 ), with at least one delivery module ( 18 ), which in a corresponding receiving opening ( 86 ) in the housing ( 12 ) is inserted, and with one in the housing ( 12 ) mounted drive shaft ( 52 ) for the conveyor module ( 18 ), and with a prefeed pump ( 16 ) whose outlet is connected to an inlet of the delivery module ( 18 ), characterized in that a drive shaft of the prefeed pump is coupled to the drive shaft for the delivery module. Fuel conveyor ( 14 ) according to claim 1, characterized in that the drive shaft ( 50 ) of the feed pump ( 16 ) by an end portion of the drive shaft ( 52 ) for the conveyor module ( 18 ) is formed. Fuel conveyor ( 14 ) according to one of the preceding claims, characterized in that the prefeed pump ( 16 ) is a gear pump, preferably an external gear pump. Fuel conveyor ( 14 ) according to claim 3, characterized in that the gear pump ( 16 ) a housing body ( 45 ) and with this fluid-tightly connected housing cover ( 70 ) having. Fuel conveyor ( 15 ) according to one of the preceding claims, characterized in that the housing ( 12 ) into which the delivery module ( 18 ), is an internal combustion engine housing, and that the prefeed pump ( 16 ) on the outside of the engine housing ( 12 ) is attached. Fuel conveyor after a of claims 1 to 4, characterized in that the Housing in which the delivery module is inserted is, an internal combustion engine housing, and that the prefeed pump is integrated in the engine housing. Fuel conveyor ( 14 ) according to one of claims 5 or 6, characterized in that the region of the engine housing ( 12 ), in or on which the delivery module ( 18 ) and the pre-feed pump ( 16 ), a total of a fuel-filled area is, with respect to a lubricant-filled area of the engine housing ( 12 ) is sealed. Fuel delivery device according to claim 7, characterized in that it comprises at least one shaft sealing ring ( 76 . 78 ) for sealing between the fuel-filled area and the lubricant-filled area. Fuel conveyor ( 14 ) according to claim 8, characterized in that it comprises two adjacent and spaced-apart shaft sealing rings ( 76 . 78 ), between which an annular space ( 104 ), from which a discharge channel ( 106 ) branches off. Fuel conveyor ( 14 ) according to one of claims 5 to 9, characterized in that a channel ( 40 ), which has an outlet of the prefeed pump ( 16 ) with an inlet of the conveyor module ( 18 ), in the engine housing ( 12 ) is trained. Fuel conveyor ( 14 ) according to one of claims 5 to 10, characterized in that a channel ( 60 ), which has an inlet of the prefeed pump ( 16 ) connects to a tank-side connection, in the engine housing ( 12 ) is trained. Fuel conveyor ( 14 ) according to one of the preceding claims, characterized in that fluidically between pre-feed pump ( 16 ) and conveyor module ( 18 ) a quantity tax body ( 27 ) is arranged. Fuel conveyor ( 14 ) according to claim 12, characterized in that the quantity control member comprises a suction throttle ( 27 ) connected to the pre-feed pump ( 16 ), preferably in their housing ( 20 ) is inserted or screwed. Fuel conveyor ( 14 ) according to one of the preceding claims, characterized in that it comprises at least one shaft sealing ring ( 78 ) for sealing between conveyor module ( 18 ) and prefeed pump ( 16 ). Fuel conveyor ( 14 ) according to one of the preceding claims, characterized in that the prefeed pump ( 16 ) a housing ( 20 ) with a tank-side inlet nozzle ( 22 ) and / or a delivery module side outlet ( 38 ) having.