EP3292311B1 - Coolant pump for an internal combustion engine - Google Patents

Description

The invention relates to a coolant pump for an internal combustion engine, with a housing having a housing cover, in which an impeller is arranged which can be rotated about an axis of rotation and which has a suction mouth coaxial to the axis of rotation, the housing forming at least one inlet channel which is configured essentially normal to the axis of rotation in order to conducting coolant from a lateral pump inlet at a distance from the axis of rotation to the suction mouth, with the inlet channel having at least one flow-influencing element, with the at least one flow-influencing element being arranged in the region of a longitudinal central axis of the inlet channel that extends normal to the axis of rotation and/or through the axis of rotation, and wherein at least one first flow-influencing element is arranged in the inlet channel between the pump inlet and the suction mouth, and at least one second flow-influencing element is arranged in the inlet channel in the area of the suction mouth, wherein the second flow-influencing element is designed to be rotationally symmetrical and is arranged coaxially to the axis of rotation. Coolant pumps are usually attached to the front of internal combustion engines and are equipped with expansive inlet ducts to the impellers in order to achieve the most homogeneous possible flow to the impellers and good efficiencies. The drive takes place, for example, mechanically via a traction means by a crankshaft or a camshaft. Overhanging inlet channels have the disadvantage that a relatively large amount of installation space is required in the direction of the axis of rotation of the impeller of the coolant pump.

The pamphlets CN 101 782 081 A and CN 103 267 018 A each disclose a coolant pump with a lateral pump inlet, with an inlet channel running essentially in a normal plane to the axis of rotation of the rotor being formed between the pump inlet and the suction mouth of the impeller of the coolant pump. A flow-influencing element formed by a guide rib is provided in the area of the suction mouth. Although pumps of this type have a smaller axial extent, a homogeneous flow onto the impellers is not guaranteed.

the CN 103 541 803 A discloses a coolant pump with a flow-influencing valve arrangement arranged in the inlet channel. Further indicates CN 202 117 753 A a coolant pump with a flow influencing rib in the inlet channel.

The object of the invention is to develop a coolant pump which, on the one hand, requires little installation space and, on the other hand, enables a homogeneous flow onto the impeller.

According to the invention, this is achieved in that at least one flow-influencing element is formed by a bulge of an inflow channel wall protruding into the inflow channel in the direction of the axis of rotation.

The flow in the inlet channel is evenly distributed over the entire available flow cross section by the at least one flow-influencing element, which is designed, for example, as a cross-section reduction device, flow dividing device or flow homogenization device. This achieves a homogeneous, uniform flow to the suction mouth and highly efficient operation of the impeller. At the same time, only a small extension of the water pump in the axial direction of an internal combustion engine is made possible in the assembled state, as a result of which installation space can be saved.

It is advantageous if—viewed in the direction of the axis of rotation—at least one flow-influencing element is designed symmetrically to the longitudinal central axis of the inlet channel.

A particularly good homogenization of the flow can be achieved if at least one first flow-influencing element is arranged in the inlet channel between the pump inlet and the suction port. The first flow-influencing element can, for example--viewed in the direction of the axis of rotation--have the shape of a flow divider or an arrowhead pointing counter to the direction of flow. In a variant of the invention, an embodiment with two arrow or flow part elements arranged next to one another, which are arranged symmetrically to the longitudinal central axis, is also possible.

The first flow-influencing element arranged in the area of the longitudinal center axis homogenizes the flow through the inlet duct by directing part of the coolant flow drawn in through the pump inlet from the area of the longitudinal center axis to the distant outer duct walls. The shape of the flow divider or the arrowhead favors this flow guidance.

The first flow-influencing element therefore has the task of fanning out the main flow so that part of the flow is pushed outwards and divided around the circumference of the suction mouth.

For example, the second flow-influencing element can have the shape of a circle viewed in the direction of the axis of rotation of the impeller, the diameter of which preferably corresponds to at least one hub diameter of the impeller and/or at least the diameter of the suction mouth. The flow-influencing element protrudes into the inlet channel as a circular disc opposite the suction mouth. The inlet channel ends outside of the circular disk in an annular channel extending through an opening angle of more than 180°, which is flow-connected in the radial direction to the suction mouth via an annular gap formed by the second flow-influencing element. The annular gap is formed by the distance between the second flow-influencing element and the suction mouth.

The inlet duct has at least one first inlet duct wall encompassing the access to the suction mouth and a second inlet duct wall running opposite the first inlet duct wall and a third inlet duct wall connecting the first and second inlet duct walls.

The inflow channel wall having the bulge is favorably the first or second inflow channel wall, the bulge preferably being formed by the housing, particularly preferably by the housing cover. The second inlet channel wall is part of the housing cover. The first flow-influencing element can be formed by a first bulge and the second flow-influencing element by a second bulge.

Advantageously - viewed in a sectional plane spanned by the axis of rotation and the longitudinal center axis of the inflow channel - between the bulge (or the maximum formation of the bulge) and the opposite inflow channel wall - measured in a direction parallel to the axis of rotation - a first smallest distance is formed, which preferably is at least 10% of the width of the inlet channel, measured in the direction of the axis of rotation, immediately adjacent (eg downstream or upstream) to the bulge. It is also advantageous if - in a normal plane to the axis of rotation - between a flank surface of the first flow-influencing element (or the outer edge of the bulge up to the maximum formation of the bulge) and at least one opposite inlet duct wall (e.g. the third inlet duct wall connecting the first and second Inlet duct wall) formed a second smallest distance measured in a plane normal to the inflow duct wall is, which is preferably at least 40% of the diameter of the suction mouth.

In the direct connection between the pump inlet or the housing supply line and the suction mouth of the impeller—the inlet opening in the impeller of the coolant pump—therefore at least one flow-influencing element is provided. This flow-influencing element can be designed as a bulge or indentation projecting into the flow of the inlet channel, which reduces the flow in a direct connection—but two or more such bulges or indentations are also possible. The aim is to create a flow resistance and to distribute the inflow of the coolant pump from one side over the entire circumference. The indentation or bulge of the first flow-influencing element preferably does not reach all the way to the opposite duct wall of the inlet duct, but can also be underflowed, with a first smallest distance being formed between the bulge and the opposite duct wall. This first distance below the bulge of the remaining inlet channel is related to the second smallest distance which is measured in a projection in the direction of the axis of rotation onto a normal plane of the axis of rotation between the first bulge and the suction mouth of the impeller: the smaller the first distance is, the greater the second distance must be in order to allow the coolant to converge after flowing under the first bulge and to enable the suction mouth of the impeller to flow uniformly.

In addition, the housing can have a second flow-influencing element above the suction mouth of the impeller, designed as a circular bulge, which causes the cooling liquid to be deflected in the direction of the impeller. If the second flow-influencing element has a diameter that corresponds to the hub diameter of the impeller, a particularly good and largely twist-free flow onto the impeller of the coolant pump can be achieved.

In a further variant, flow-influencing guide walls, for example guide plates, guide ribs or the like, can be provided in the flow path, which feed the flow in a targeted manner to the suction mouth. In a variant of the invention, these baffles can also be arranged directly on the edge of the suction mouth. For example, at least one guide wall can be arranged directly in the area of the circumference of the suction mouth of the impeller and can be straight or slightly spiral-shaped in order to provide a corresponding deflection to achieve the coolant. In addition or as an alternative to this, at least a guide wall can also be arranged in the area between the suction mouth and the pump inlet in the inlet channel.

It is particularly favorable if two guide walls facing away from each other form a double spiral and are arranged on the side of the suction mouth facing away from the pump inlet in such a way that the two partial flows of the coolant flowing in the circumferential direction on both sides of the suction mouth are guided to the suction mouth. The coolant flowing tangentially past the suction mouth of the impeller is diverted in the direction of the suction mouth by the double spiral. Depending on the desired twist, this double spiral can be designed essentially symmetrically to a plane spanned by the longitudinal center axis of the inlet channel and the axis of rotation, or asymmetrically.

The coolant is first fanned out by the first flow-influencing element in the direction of the jacket of the housing and then fed homogeneously, i.e. without twisting, radially to the suction mouth before it flows axially through the suction mouth into the blade channels of the impeller. It is particularly advantageous if the inlet channel has a flow cross section that widens between a first end on the inlet side and a second end on the suction mouth side. The flow cross-section thus increases steadily or continuously from the pump inlet to the suction port. The flow velocity is reduced by the widening cross-section, which supports the homogenization of the flow. A particularly uniform inflow to the suction mouth can be achieved if—viewed in the direction of the axis of rotation—the second end of the inlet channel on the suction mouth side is designed as a circular sector concentric to the suction mouth, with the circular sector preferably extending at an angle of about 180°. The second end of the inlet duct, designed in the shape of a sector of a circle, forms a flow-calming collection space in which turbulence and swirl components in the coolant flow are reduced.

Compared to designs known from the prior art, the invention allows both a reduction in the axial extent of the coolant pump and a homogeneous supply of the coolant to the suction mouth of the impeller that is optimal in terms of efficiency. Since the coolant is not supplied in the direction of the axis of rotation, but rather in the normal direction, lower installation space requirements can be met.

Due to the homogeneous supply of the coolant to the suction mouth, a largely twist-free flow onto the impeller of the coolant pump is achieved. This in turn, enables uniform performance at different operating ranges. Due to the uniform distribution of the coolant mass over the entire circumference of the water pump geometry, all pump blades of the coolant pump are operated in the optimum range in terms of vibration and pumping efficiency.

• Fig. 1 einen Teil einer Brennkraftmaschine mit einer erfindungsgemäßen Kühlmittelpumpe in einer Schrägansicht,
• Fig. 2 die Brennkraftmaschine in einer stirnseitigen Ansicht,
• Fig. 3 den Antrieb der Kühlmittelpumpe aus Fig. 1 und 2,
• Fig. 4 die erfindungsgemäße Kühlmittelpumpe in einer Vorderansicht,
• Fig. 5 die Kühlmittelpumpe in einer Draufsicht,
• Fig. 6 die Kühlmittelpumpe in einem Schnitt gemäß der Linie VI - VI in Fig. 4,
• Fig. 6a die Kühlmittelpumpe in einem Schnitt analog zu Fig. 6, in einer Variante,
• Fig. 7 die Kühlmittelpumpe in einem Schnitt gemäß der Linie VII - VII in Fig. 5 in einer ersten erfindungsgemäßen Ausführungsvariante und
• Fig. 8 die Kühlmittelpumpe in einem Schnitt gemäß der Linie VII - VII in Fig. 5 in einer zweiten erfindungsgemäßen Ausführungsvariante.

The invention is explained in more detail below with reference to the non-limiting figures. show in it

• 1 part of an internal combustion engine with a coolant pump according to the invention in an oblique view,
• 2 the internal combustion engine in a front view,
• 3 the coolant pump drive Figures 1 and 2 ,
• 4 the coolant pump according to the invention in a front view,
• figure 5 the coolant pump in a plan view,
• 6 the coolant pump in a section according to the line VI - VI in 4 ,
• Figure 6a the coolant pump in a section analogous to 6 , in a variant,
• 7 the coolant pump in a section according to the line VII - VII in figure 5 in a first embodiment variant according to the invention and
• 8 the coolant pump in a section according to the line VII - VII in figure 5 in a second embodiment variant according to the invention.

Parts with the same function are provided with the same reference symbols in the design variants.

1 1 shows an internal combustion engine 1 with a cylinder head 2 and a cylinder block 3. A coolant pump 4 according to the invention, designed as a radial pump, is attached to the end face of the cylinder head 2. The coolant pump 4 has a housing 5 with a housing cover 6 in which an impeller 8 designed as a radial impeller or mixed flow impeller and rotatably mounted about an axis of rotation 7 is arranged. The impeller shaft 9 of the impeller 8 is driven in the present case by a camshaft 10 via a toothed belt 11, as shown in FIG 3 can be seen. Reference number 12 designates the cover of the drive.

The coolant flows via a supply line 14 into the pump inlet 15 and flows through the coolant pump 4 and is conveyed by the pump through an overflow channel 16 into the cylinder head 2 . If necessary, a thermostatic valve can be arranged in the area of the pump inlet 15 . After flowing through the cooling chambers of the cylinder head 2 (not shown in detail), the coolant leaves the cylinder head 2 via a discharge line 17 and is routed to a radiator (not shown in detail).

The housing 5 of the coolant pump 4 forms an inlet channel 18, which extends at least between the pump inlet 15 and the suction mouth 19 of the Impeller 8 extends. The inlet channel walls 18a, 18b, 18c of the inlet channel 18 have a first inlet channel wall 18b that encompasses the access to the suction mouth 19, a second inlet channel wall 18c that runs opposite the first inlet channel wall, and a third inlet channel wall 18a that connects the first inlet channel wall 18b and the second inlet channel wall 18c. These are formed by the housing jacket 5a, by the housing base 5b (third inlet channel wall 18a) and by the housing cover 6 (second inlet channel wall 18c). Between a first end 181 on the inlet side and a second end 182 of the inlet channel 18 on the suction mouth side, the flow cross section of the inlet channel 18 widens continuously (or continuously). Viewed in the direction of the axis of rotation 7, the second end 182 of the inlet channel 18 on the suction mouth side is designed as a circular sector 182' concentrically with the suction mouth 19, which circular sector 182' extends at an angle α of about 180°, as well 4 is recognizable.

A first flow-influencing element 20 formed by a first bulge 20a of the second inlet duct wall 18c of the housing cover 6, which protrudes into the inlet duct 18, is arranged in the inlet duct 18; 18 directed arrowhead. The first bulge 20a is formed by the housing cover 6 in the exemplary embodiments.

Measured in the direction of the axis of rotation 7, there is a first distance h between the first flow-influencing element 20 and the opposite first inlet channel wall 18b, which is immediately adjacent, e.g. downstream or upstream of the first flow-influencing element 20 is ( Figures 6, 6a ). The first distance h extends between the maximum shape of the bulge 20a and the first inlet channel wall 18b. Between a flank surface 20b of the first flow-influencing element 20 and at least one opposite inflow duct wall (here, for example, the third inflow duct wall 18a, the housing shell 5a), there is also a second distance k, measured in a normal plane ε ₁ on the inflow duct wall 18a, which is at least 40% of the Diameter D of the suction mouth 19 is ( 4 ). The area from the outer edge of the bulge 20a or of the first flow-influencing element 20 to the maximum formation, for example of the bulge 20a, is referred to here as flank surface 20b.

The first flow-influencing element 20 is spaced from the suction port 19 (or arranged between the pump inlet 15 and the suction port 19), wherein a third distance x, measured in a normal plane ε ₂ to the axis of rotation 7 , between the first flow-influencing element 20 and the suction mouth 19 is at least twice the diameter D of the suction mouth 19 .

Furthermore, a second flow-influencing element 21 embodied as a second bulge 21a of the duct wall 18c of the inlet duct 18 protrudes into the flow S of the inlet duct 18 , which element 21 is also formed here by the housing cover 6 . Viewed in the direction of the axis of rotation 7 of the impeller 8 , the second flow-influencing element 21 has the shape of a circular disc whose diameter D ₂₁ corresponds at least to the hub diameter d of the impeller 8 . In particular, it is favorable if the diameter D _21b of the tip 21b of the second bulge 21a facing the suction mouth 19 is approximately the same as the hub diameter d. The inlet geometry formed by the housing base 5b to the impeller 8 has a defined radius r in the area of the suction mouth 19 for the streamlined axial deflection of the radial inlet flow S. As in Figure 6a is shown, the area of the housing base 5b surrounding the suction mouth 19 can form an annular bead 51 narrowing the radial flow cross section, which is arranged between the surrounding annular space 183 in the outer area of the second end 182 of the inlet channel 18 and the suction mouth 19. The bead 51 can be formed circumferentially, or it can have radial interruptions or projections, which serve as radial flow guide surfaces directed towards the suction mouth 19 . The bead 51 increases the design freedom for the outer contour of the housing 5. Instead of the bead 51, individual local radial indentations can also be provided. Of course, it is also possible to provide radial guide ribs 52 or guide vanes, which guide the flow from the surrounding annular space 183 to the suction mouth 19, in addition to or instead of the bead 51, the interruptions, projections or indentations. Individual guide ribs 52 of this type, which 4 are indicated only schematically, can be indicated distributed evenly over the circumference around the suction mouth 19 .

The first flow-influencing element 20 is also at a distance from the second flow-influencing element 21, the fourth distance y - measured in a normal plane ε ₂ to the axis of rotation 7 - between the first flow-influencing element 20 and the second flow-influencing element 21 being at least 40% of the diameter D of the suction mouth is 19 ( Figure 6.6a ).

7 shows a coolant pump without additional guide surfaces. The housing cover is removed, so there are first and second flow-affecting elements not apparent. The impeller 8 is indicated schematically by dashed lines. The partial flows Si, _S2 formed by the flow-influencing elements 20, 21 flow along the circumference of the suction mouth 19.

In the 8 illustrated embodiment of the invention differs from 7 in that in the region of the second end 182 of the inlet channel 18 on the suction mouth side, two guide walls 22a, 22b that face away from one another and form a double spiral 22 are arranged on the side of the suction mouth 19 that faces away from the pump inlet 15 in such a way that the two partial flows flowing in the circumferential direction on both sides of the suction mouth 19 Si, S ₂ of the coolant to the suction port 19 are performed. The coolant flowing tangentially past the suction mouth 19 of the impeller 8 is diverted in the direction of the suction mouth 19 by the double spiral 22 . In the exemplary embodiment, the baffles 22a, 22b are designed essentially symmetrically to a plane ε ₃ spanned by the longitudinal center axis 18 ′ of the inlet channel 18 and the axis of rotation 7 . Viewed in the direction of the axis of rotation 7 , the longitudinal central axis 18 ′ can form an axis of symmetry of the inflow channel 18 . If an input twist is desired when entering the suction mouth 19, the guide walls 22a, 22b can also be designed asymmetrically.

The coolant is first fanned out in the direction of the housing casing 5a by the first flow-influencing element 20 and then fed homogeneously, ie without twisting or at least with little twisting, to the suction mouth 19 essentially radially with respect to the axis of rotation 7 . It then flows axially, i.e. in the direction of the axis of rotation 7, through the suction mouth 19 into the blade channels of the impeller 8. The second end 182 of the inlet channel 18, which is designed in the shape of a sector of a circle, forms a flow-calming collection chamber in which turbulence and swirl components in the coolant flow are reduced.

The coolant pump 4 according to the invention enables both a reduction in the installation space in the direction of the axis of rotation 7 and an efficient, homogeneous supply of the coolant to the suction mouth 19 of the impeller 8.

Due to the homogeneous supply of the coolant to the suction port 19, a largely swirl-free flow onto the impeller 8 of the coolant pump 4 is achieved. This in turn allows for consistent performance across different operating regimes. Due to the uniform distribution of the coolant mass over the entire circumference of the water pump geometry, all pump blades of the coolant pump 4 are operated in the optimum range with regard to vibration and pumping efficiency.

Claims (12)

1. Coolant pump (4) for an internal combustion engine (1), having a housing (5) which has a housing cover (6) and in which an impeller (8) is arranged which can rotate about an axis of rotation (7) and which has a suction orifice (19) coaxial with the axis of rotation (7), wherein the housing (5) forms at least one intake channel (18) designed substantially normal to the axis of rotation (7), in order to guide coolant from a lateral pump inlet (15), which is spaced apart from the axis of rotation (7), to the suction orifice (19), and wherein the intake channel (18) has at least one flow-influencing element (20, 21), wherein the at least one flow-influencing element (20, 21) is arranged in the region of a longitudinal central axis (18') of the intake channel (18), which longitudinal central axis (18') is designed to extend normal to the axis of rotation (7) and/or through the axis of rotation (7), wherein at least one first flow-influencing element (20) is arranged in the intake channel (18) between the pump inlet (15) and the suction orifice (19), and wherein at least one second flow-influencing element (21) is arranged in the intake channel (18) in the region of the suction orifice (19), wherein the second flow-influencing element (21) is of rotationally symmetrical design and is arranged coaxially with respect to the axis of rotation (7), characterised in that at least one flow-influencing element (20, 21) is formed by a bulge (20a, 21a), projecting in the direction of the axis of rotation (7) into the intake channel (18), of an intake channel wall (18c).
2. Coolant pump (4) according to claim 1, characterised in that at least one flow-influencing element (20, 21) is formed symmetrically with respect to the longitudinal central axis (18') of the intake channel (18).
3. Coolant pump (4) according to claim 1 or 2, characterised in that, as viewed in the direction of the axis of rotation (7), the second flow-influencing element (21) has the shape of a circle, wherein the diameter (D₂₁) of the circle preferably corresponds to at least one hub diameter (d) of the impeller (8).
4. Coolant pump (4) according to one of the claims 1 to 3, characterised in that, as viewed in a sectional plane (ε₃) spanned by the axis of rotation (7) and the longitudinal central axis (18') of the intake channel (18), a first smallest distance (h), as measured in a direction parallel to the axis of rotation (7) is formed between the first flow-influencing element (20) and the opposite intake channel wall (18b), which is preferably at least 10% of the width (b), as measured in a direction parallel to the axis of rotation (7), of the intake channel (18) immediately adjacent to the first flow-influencing element (20).
5. Coolant pump (4) according to claim 4, characterised in that, as viewed in a normal plane (ε₂) to the axis of rotation (7), between a flank surface (20b) of the first flow-influencing element (20) and at least one opposite intake channel wall (18a) there is formed a second smallest distance (k), as measured in a normal plane (ε₁) to the intake channel wall (18a), which is preferably at least 40% of the diameter (d) of the suction orifice (19).
6. Coolant pump (4) according to one of claims 1 to 5, characterised in that the first flow-influencing element (20) is spaced from the suction orifice (19) and/or from the second flow-influencing element (21).
7. Coolant pump (4) according to one of claims 1 to 6, characterised in that a third smallest distance (x) between the first flow-influencing element (20) and the suction orifice (19) in a normal plane (ε₂) to the axis of rotation (7) is at least twice the diameter (d) of the suction orifice (19).
8. Coolant pump (4) according to one of claims 1 to 7, characterised in that, as measured in a normal plane (ε₂) to the axis of rotation (7), a fourth smallest distance (y) between a first flow-influencing element (20) and a second flow-influencing element (21) is at least 40% of the diameter (d) of the suction orifice (19).
9. Coolant pump (4) according to one of claims 1 to 8, characterised in that at least one guide wall (22a, 22b) directing the coolant in the direction of the suction orifice (19) is arranged in the intake channel (18).
10. Coolant pump (4) according to claim 9, characterised in that two guide walls (22a, 22b) facing away from one another form a double spiral (22) and are arranged on the side of the suction orifice (19) facing away from the pump inlet (15), preferably essentially symmetrically with respect to a plane (ε₃) spanned by the longitudinal central axis (18') of the intake channel (18) and the axis of rotation (7) of the impeller (8).
11. Coolant pump (4) according to one of the claims 1 to 10, characterised in that the intake channel (18) has a flow cross-section widening between an intake-side first end (181) and a suction-orifice-side second end (182).
12. Coolant pump (4) according to claim 11, characterised in that the suction-orifice-side second end (182) of the intake channel (18) is designed as a circular sector (182') with the same axis as the suction orifice (19), wherein the circular sector (182') preferably extends through an angle (α) of approximately 180°.

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