Title of Invention

FUEL INJECTION PUMP

Abstract

The invention relates to a fuel injection pump for internal combustion engines, having a pump casing in which a supply device is accommodated, the operation of which is controlled with the aid of a control unit which is accommodated in a control unit housing which is mounted on the pump casing. In order to ensure sufficient cooling of the control unit housing, between the upper side of the pump casing and the lower side of the control unit housing a cavity-is formed into which a fuel feed opens and from which a connecting line leads to the supply device, in the cavity a filling piece having a bell-shaped intake (18) being arranged, via which the supplied fuel passes from the cavity via the connecting line to the supply device.

Full Text

Fuel Injection Pump Prior Art The invention relates to a fuel injection pump for internal combustion engines, having a pump casing in which a supply device is accommodated, the operation of which is controlled with the aid of a control unit which is accommodated in a control -unit housing which is mounted on the pump casing. An injection pump of this type is disclosed in DE-A 37 03 073 Al. In the case of the known injection pump, the fuel to be supplied is conducted through the control unit housing for cooling purposes. In practice, the heating of electrical components in the control unit housing has proven problematical. The object of the invention is to ensure sufficient cooling of the control unit housing without fuel washing around electronic components contained in the interior of the control unit housing. The object is achieved in the case of a fuel injection pump for internal combustion engines, having a pump casing in which a supply device is accommodated, the operation of which is controlled with the aid of a control unit which is accommodated in a control unit housing which is mounted on the pump casing, in that between the upper side of the pump casing and the lower side of the control unit housing a cavity is formed into which a fuel feed opens and from which a connecting line leads to the supply device, and in that in the cavity a filling piece having at least one deflecting duct is arranged, via which the supplied fuel passes from. the fuel feed to the lower side of the control unit housing. Advantages of the invention The effect achieved thereby is that the lower side of the control unit housing is continuously wetted with fuel during operation, which leads to a considerably improved cooling effect. One particular version of the invention is characterized in that a mask is formed on the filling piece, the said mask, in the installed state of the filling piece, surrounding the fuel feed in the pump casing. The mask ensures that the fuel passes from the fuel feed into the deflecting duct. The mask prevents the fuel from passing directly from the fuel feed -to the connecting line in the form of a type of bypass flow. A further particular version of the invention is characterized in that the deflecting duct emerges from a clip which is formed on the filling piece and in the installed state of the filling piece is held in a pocket which is recessed in the pump casing in the region of the fuel feed. This firstly improves the effect of the mask. Secondly, the clips held in the pockets are used to keep the filling piece in position in the installed state. A further particular version of the invention is characterized in that a bell-shaped intake is formed in that surface of the filling piece which faces towards the control unit housing, the said bell-shaped intake being connected, in the installed state of the filling piece, to the connecting line in the pump casing. The bell-shaped intake acts as a funnel and ensures that the fuel is sucked in at the top and the formation of air bubbles is prevented. Nevertheless, air present in the cavity is distributed in very small units in the sucked-in fuel with the aid of the filling piece according to the invention. A further particular version of the invention is characterized in that all of the fuel ducts provided in the filling piece are designed in such a manner that they have a small flow resistance. This ensures that the pressure loss through the filling piece is kept as small as possible. A further particular version of the invention is characterized in that the intake of the connecting line in the pump casing is of funnel-shaped design. This ensures that the pressure loss is kept small. A further particular version of the invention is characterized in that two deflecting ducts are provided on opposite sides of the filling piece. This affords the advantage that the filling piece can be connected onto two opposite sides of the pump casing. A further particular version of the invention is characterized in that a plurality of downwardly open chambers are formed in that surface of the filling piece which faces towards the pump casing in the installed state of the filling piece. The effect achieved by dividing the lower side of the filling piece into a multiplicity of chambers is that the size of the air volumes possibly enclosed in the cavity is reduced to a safe value. Further advantages, features and details of the invention emerge from the following description in which an exemplary embodiment of the invention is described in detail with reference to the drawing. In this case, the features mentioned in the claims and in the description may be essential for the invention by themselves or in any desired combination in each case. Drawing In the drawing: Figure 1 shows a perspective illustration of a filling piece according to the invention; Figure 2 shows a rear view of the filling piece from Figure 1; and Figure 3 shows a view below of the filling piece in Figure 1. The filling piece illustrated perspectively in Figure 1 is held in a cavity which is formed between the upper side of the pump casing and the lower side of the control unit housing of an injection pump according to the invention. Opening into the cavity is a fuel feed through which fuel passes from a fuel tank into the cavity. The fuel can be supplied either with the aid of a prefeed pump in the cavity or can be sucked up just by the feed pump of the injection pump. A connecting line leads from the cavity to the supply device of the injection pump. The opening for the connecting line is arranged in the cavity above the opening for the fuel feed. The effect achieved by this is that the cavity is continuously filled up to a certain level with fuel. It cannot be avoided during operation that there is also a certain amount of air in the cavity. The cavity is bounded downwards by the pump casing of the injection pump. The cavity is bounded upwards by the lower side of a control -unit housing. The control unit housing is used for holding electronic components which heat up during operation. The filling piece illustrated in Figure 1 is held in the fitted state in the cavity in such a manner that its upper side 1 faces towards the lower side of the control unit housing. In the fitted state, the upper side 1 of the filling piece is arranged horizontally as a rule. From the upper side 1 of the filling piece, eight flat side surfaces 2 to 9 extend essentially in a vertical direction. A deflecting duct 11 is recessed in the flat side surface 9 of the filling piece. A deflecting duct 12 is recessed in the flat side surface 5 of the filling piece. The deflecting duct 11 extends from a clip 13, which is used for positioning the filling piece, as far as the upper side 1 of the filling piece. The deflecting duct 12 extends from a clip 14 likewise as far as the upper side 1 of the filling piece. A mask 15 is formed on the clip 13, the said mask, in the fitted state, surrounding the inlet opening of the fuel feed in the cavity. A corresponding mask is formed on the clip 14. The fuel entering into the cavity is conducted to the upper side 1 of the filling piece by the deflecting ducts 11 and 12. This ensures that the lower side of the control unit housing is wetted with fuel. The arrangement of the deflecting duct is selected in such a manner that the fuel, under a certain mass flow, strikes against that surface of the control unit over which the electronic module having the greatest heat loss capacity is seated. By means of correction [sic], the heat is dissipated. A bell-shaped intake 18 is formed in the centre of the upper side 1 of the filling piece. The bell-shaped intake 18 is connected via a connecting pipe 19 to a fuel outlet opening 20. In the installed state of the filling piece, the fuel outlet opening 20 is arranged in the region of the intake of the connecting line to the supply device of the injection pump. The fuel outlet opening 20 is situated on a bevelled surface 21 of the filling piece. By means of the arrangement of the bell-shaped intake at the top, air collected at the top is continuously removed and it is therefore ensured that the lower side of the control unit; housing remains wetted with fuel. Moreover, a small flow resistance for the fuel is obtained by the funnel-shaped configuration of the bell-shaped intake. Two fixing pins 25 and 2 5 which are of slotted design at the ena protrude rrom the lower side ot the filling piece. The fixing pins 25 and 26 serve to fix the filling piece in the cavity in the installed state. The view from below illustrated in Figure 3 reveals that the filling piece is divided into a multiplicity of cuboidal chambers 30, 31 which are downwardly open. The chambers 30, 31 are formed by vertically running partitions which are arranged perpendicularly with respect to one another. The filling piece according to the invention ensures that the fuel is conducted further between the pump casing and the control unit housing. In the process, the drop in pressure is minimized. In addition, the configuration according to the invention of the filling piece ensures that air is continuously sucked out of the cavity. In the installed state of the filling piece, a fuel flow flows from. the fuel feed into the intermediate space which is formed between the lower side of the control unit housing and the upper side of the filling piece. The fuel deploys its cooling effect in this intermediate space. From the intermediate space, the fuel passes via the bell-shaped intake 18 and the connecting pipe 19 to the connecting line (not illustrated) to the supply device of the injection pump. By means of the configuration of the filling piece according to the invention in the manner that the fuel is sucked off over the highest point by means of a bell-shaped intake, or at least is sucked off via the bell-shaped intake, or at least can only flow off via the bel 1 - shaped intake, it is ensured chat, the cavi ty is filled at least as far as the upper side 1 of the filling piece. WE CLAIM : 1. A fuel injection pump for internal combustion engines, having a pump casing in which a supply device is accommodated, the operation of which is controlled with the aid of a control unit which is accommodated in a control unit housing which is mounted on the pump casing, characterized in that between the upper side of the pump casing and the lower side of the control unit housing a cavity is formed into which a fuel feed opens and from which a connecting line leads to the supply device, and in that in the cavity a filling piece having at least one deflecting duct (11) is arranged, via which the supplied fuel passes from the fuel feed to the lower side of the control unit housing; a bell-shaped intake (18) is formed in that surface (1) of the filling piece which faces towards the control unit housing, the said bell-shaped intake being connected, in the installed state of the filling piece, to the connecting line in the pump casing. 2. The fuel injection pump as claimed in claim 1, wherein a mask (15) is formed on the filling piece, the said mask, in the installed state of the filling piece, surrounding the fuel feed in the pump casing. 3. The fuel injection pump as claimed in any one of the preceding claims, wherein the deflecting duct (11) emerges from a clip (13) which is formed on the filling piece and in the installed state of the filling piece is held in a pocket which is recessed in the pump casing in the region of the fuel feed. 4. The fuel injection pump as claimed in any one of the preceding claims, wherein all of the fuel ducts (11, 12, 19) provided in the filling piece are formed in such a manner that they have a small flow resistance. 5. The fuel injection pump as claimed in any one of the preceding claims, wherein the intake of the connecting line in the pump casing is funnel-shaped. 6. The fuel injection pump as claimed in any one of the preceding claims, wherein two deflecting ducts (11, 12) are provided on opposite sides of the filling piece. 7. The fuel injection pump as claimed in any one of the preceding claims, wherein a plurality of downwardly open chambers (30, 31) are formed in that surface of the filling piece which faces towards the pump casing in the installed state of the filling piece.

Documents:

abs-in-pct-2002-651-che.jpg

in-pct-2002-651-che-abstract.pdf

in-pct-2002-651-che-claims .pdf

in-pct-2002-651-che-correspondance others.pdf

in-pct-2002-651-che-correspondance po.pdf

in-pct-2002-651-che-description complete.pdf

in-pct-2002-651-che-drawings.pdf

in-pct-2002-651-che-form 1.pdf

in-pct-2002-651-che-form 26.pdf

in-pct-2002-651-che-form 3.pdf

in-pct-2002-651-che-form 5.pdf

in-pct-2002-651-che-other documents.pdf

in-pct-2002-651-che-pct.pdf