EP2013457B1 - Cooling system of an internal combustion engine with two heat exchangers - Google Patents

Description

The present invention relates to a cooling system of an internal combustion engine having two heat exchangers and a coolant pump, which has two inlets and two outlets and one in a circular in cross-section pump chamber of a pump housing rotatably arranged impeller, wherein in not flowed through by coolant heat exchangers, only one inlet and two outlets are flowed through.

Cooling systems for internal combustion engines have already become known in many forms. For example, using the DE 40 30 200 C2 an engine cooling system has become known, which has a rotationally driven via a crankshaft of the engine coolant pump having two outlets, one of which discharges coolant into an associated inlet of a cylinder bank of a V-engine coolant and the coolant pump has only one suction line insert portion, so a Inlet through which coolant flows into the coolant pump and in the direction of the axis of rotation of the impeller of the coolant pump. Thus, the coolant pump in the direction of the axis of rotation of the impeller has a large axial length.

Based on DE 198 09 123 B4 a water pump for the cooling circuit of an internal combustion engine has become known, wherein the water pump has an axially extending collection opening into which coolant from several, can be closed by means of a rotary valve inlet openings.

A cooling system with two heat exchangers and a pump with two inlets and one outlet is off DE10055452 known.

Finally, based on the DE 199 56 732 B4 a cooling device for a motor has become known, wherein the water pump provided in this cooling device has two inlets and two outlets, wherein a first outlet is traversed at a small active circuit and the second inlet is flowed through with a large active circuit. The small circle or cycle corresponds to the Coolant circuit during the warm-up phase of the engine, so while the engine has not yet reached operating temperature and the coolant is not passed through a corresponding coolant heat exchanger. The large circle corresponds to that with respect to the coolant circuit with actively flowed through the coolant heat exchanger, so if the engine has already reached its operating temperature. Fig. 11 of this document shows that the coolant pump is flowing in the direction of the axis of rotation of the impeller and thus in turn has a large axial length.

If now a coolant pump to be provided on an internal combustion engine having two horizontally opposed cylinders, ie an internal combustion engine in boxer or counter-rotor design, the coolant pump can be directly driven via a correspondingly shaped crankshaft stub of the engine, so that the coolant pump, for example, in a direction of travel equipped with the internal combustion engine vehicle front end side of the internal combustion engine are arranged so that eliminates a Drehachsrichtung in the impeller of the internal combustion engine long design. This is especially true when it is the vehicle is a motorcycle in which the clear distance between the front of the engine and the front wheel is short and thus exudes such a long design. Also, it may be necessary in such a motorcycle due to a known as Telelever front wheel guide embodiment of the stem of the motorcycle to equip the cooling system with two independent heat exchangers, one of which is adjacent to the described Vorderradführung arranged.

Proceeding from this, the present invention is based on the object, a generic cooling system of an internal combustion engine such that the required in Drehachsrichtung the impeller axial space of the coolant pump can be significantly reduced compared to known coolant pumps.

The invention now has to solve this problem the features specified in claim 1. Advantageous embodiments thereof are described in the further claims.

The invention now provides a cooling system of an internal combustion engine with two heat exchangers and a coolant pump, which has two inlets and two outlets and one in a circular in cross-section pump chamber of a pump housing rotatably arranged impeller, wherein in non-coolant flowed through heat exchangers only one inlet and two outlets are flowed through and flows through both inlets and both outlets when flowed through by coolant heat exchangers.

Thus, if the internal combustion engine is not yet at operating temperature, with active small circuit, the coolant pump flows through only one inlet and two outlets, while in large active circuit, so if both heat exchangers are flowed through both inlets and both outlets of the coolant pump , This leads to an efficient mixing of the two coolant circuits of both heat exchangers and due to the elimination of the necessity of bundling the coolant circuits from both heat exchangers, for example by means of a T-piece before the inlet of the coolant pump to a cooling system requiring less space. The use of such a tee in front of the inlet of the coolant pump would be required if the coolant pump has only one inlet, as is the case with known coolant pumps or with coolant pumps, although they have two inlets, but of which of whether the large cooling circuit or the small cooling circuit is active, only one inlet is flowed through.

A short in the direction of the axis of rotation of the impeller design of the coolant pump can be achieved in that the inlets and outlets are formed by itself from the pump housing in pairs parallel directed away extending tubular piece approaches. Thus, a configuration of the coolant pump is achieved, wherein each one inlet parallel to an outlet runs and the inlets and outlets, for example, at right angles to the axis of rotation of the impeller, so that the coolant pump in Drehachsrichtung of the impeller has a very short construction.

In order to achieve a good mixing of the flowing through the two inlets into the pump chamber coolant with appropriate temperature compensation and thus the same temperature both of the respective outlet of the coolant pump cylinder of the boxer engine in the pump chamber of the pump housing, it is provided according to the invention that the inlets and outlets relative to the axis of rotation of the impeller are arranged crosswise opposite each other and offset in the direction of the axis of rotation of the impeller. Thus, it is achieved that the coolant flows flowing through the two inlets into the pump chamber, for example, but not butt, which is unfavorable in terms of flow, but the inflowing coolant flows at a radial distance from the axis of rotation of the impeller from considered meet the impeller and so for a low energy requirement for the drive power of the coolant pump. The coolant thus flowing into the pump chamber can now flow through passages for the flow of the coolant from the suction side, ie the inlet side, to the pressure side, ie the outlet side, in the impeller, with the inlets and outlets being offset from one another in the direction of the axis of rotation of the impeller for this purpose are.

According to a preferred embodiment, the inlets are arranged relative to the pump chamber such that the coolant acts on the impeller tangentially from the outer periphery of the impeller ago. In order to avoid that the two coolant inlet streams entering the pump chamber encounter each other unfavorably in terms of flow before the impeller is impinged, it is provided according to a development of the invention that the pump chamber has a dividing wall which separates the coolant inlet streams from each other before the impeller is acted upon extends from an outer wall of the pump housing toward an end face of the impeller. Thus, the two coolant inlet streams are directed into the pump chamber, that they are transported from the rotating impeller via the passages of the impeller to the outlet side with active mixing of the two coolant inlet streams in the pump chamber.

So that the impeller can be positively driven by a crankshaft stub of the engine, it may have on its intended to engage with the crankshaft stub page a form-fitting hub, with which the impeller forms a positive shaft-hub connection with the crankshaft stub and thus an axial length requiring interposition of an auxiliary drive is avoided.

• Fig. 1 eine schematische Darstellung eines Kühlsystems nach einer Ausführungsform gemäß der vorliegenden Erfindung mit einem Zweizylinder-Boxermotor und zwei Wärmetauschern;
• Fig. 2 eine Ansicht auf eine Kühlmittelpumpe von ihrer Rückseite her;
• Fig. 3 eine teilweise geschnittene Darstellung der Kühlmittelpumpe nach Fig. 2 in einer Ansicht von schräg oben;
• Fig. 4 eine Querschnittsansicht der Kühlmittelpumpe;
• Fig. 5 eine teilweise geschnittene Darstellung der Kühlmittelpumpe nach Fig. 1;
• Fig. 6 eine perspektivische Draufsichtansicht auf die Kühlmittelpumpe von vorne; und
• Fig. 7 eine geschnittene perspektivische Darstellung der Kühlmittelpumpe zur Erläuterung der Strömungsbahnen.

The invention will now be explained in more detail below with reference to the drawing. This shows in:

• Fig. 1 a schematic representation of a cooling system according to an embodiment according to the present invention with a two-cylinder boxer engine and two heat exchangers;
• Fig. 2 a view of a coolant pump from its rear side;
• Fig. 3 a partially sectioned illustration of the coolant pump according to Fig. 2 in a view from diagonally above;
• Fig. 4 a cross-sectional view of the coolant pump;
• Fig. 5 a partially sectioned illustration of the coolant pump according to Fig. 1 ;
• Fig. 6 a top perspective view of the coolant pump from the front; and
• Fig. 7 a sectional perspective view of the coolant pump to explain the flow paths.

Fig. 1 The drawing shows a schematic representation of a cooling system according to the present invention with a two-cylinder boxer engine as an internal combustion engine. The engine 1 has two cylinders 2, 3, through which the coolant circulating in the cooling system flows. In the cooling system is a diagrammatic only thermostat 4, which is designed so that it can switch the cooling system from the small circle or circuit to the large circle or circuit. If the engine 1 is in the warm-up phase, that is, if it has not yet reached its operating temperature, then the thermostat 4 ensures that the coolant circulated by a coolant pump 5 in the cooling system is pumped through the cylinders 2, 3 but not through the heat exchanger 6 , 7 in the cooling system.

Now, if the engine 1 has reached its operating temperature, the thermostat 4 ensures that the two heat exchangers 6, 7 are flowed through by the coolant.

The coolant pump 5 now has two inlets 8, 9 and two outlets 10, 11. If now the small circuit is active, so enters coolant in the coolant pump 5 only via an inlet 8 and leaves the coolant through both outlets 10, 11 and from there through cylinder inlets 12, 13 in a corresponding coolant jacket of the cylinder 2, 3 a , After the coolant has flowed through the cylinders 2, 3, after a corresponding heating, it leaves through cylinder outlets 14, 15 and flows in the direction of the arrow to the thermostat 4. If the engine 1 has not yet reached its operating temperature, the thermostat 4 ensures that the Coolant flows back to the inlet 8 of the coolant pump 5.

If, on the other hand, the engine 1 has reached its operating temperature, then the thermostat 4 ensures that the heated coolant flowing out of the cylinder outlets 14, 15 flows through the heat exchangers via corresponding heat exchanger inlets 16, 17 of the heat exchangers 6, 7 and back into their respective heat exchanger outlets 18, 19 Direction to the coolant pump 5 flows. Now, if this large circle is active, so the two heat exchangers 6, 7 are flowed through, then the coolant flows into the coolant pump 5 both via the inlet 8 and via the inlet 9 and leaves the coolant pump 5 via the outlets 10, 11 and enters the cylinders 2, 3 again.

Fig. 2 The drawing now shows in a view from the rear of the coolant pump 5 with its inlets 8, 9 and their outlets 10, 11. As it is readily apparent, are the two inlets 8, 9 relative to the axis of rotation of in Fig. 3 apparent impeller 20 crosswise to each other and also the outlets 10, 11 are crosswise opposite each other. The outlets 10, 11 lie in the axial direction of the axis of rotation of the impeller 20 offset from the inlets 8, 9th

Fig. 4 The drawing now shows a sectional view of the coolant pump 5 with its pump housing 21 and a formed in the pump housing 21, in cross-section circular pump chamber 22. In the pump chamber 22, the impeller 20 is rotatably received. The coolant flows into the pump housing 21 via an inlet 8 and is prevented from flowing into the space 26 by a partition wall 23 which extends from an outer wall 24 of the pump housing 21 towards an end face 25 of the pump wheel 20. which represents the inflow region of the coolant flowing from the inlet 9 into the pump housing 21, so that the coolant sub-streams entering through the two inlets 8, 9 do not butt against one another and thus flow-unfavorably.

The coolant flowing in via the inlet 8 flows through a passage 27 of the impeller and from there into the region of a space 28 formed in the pump housing 21, from which it can flow via the outlet 10 to the cylinder inlet 13 of the cylinder 3.

The impeller 20 has a hub 29, with which it can be brought into a positive engagement with a not shown crankshaft stub of the engine 1 to be rotated directly by the crankshaft can.

Fig. 5 The drawing now shows a partially sectioned illustration of the coolant pump after Fig. 2 in which the outer wall 24 has been omitted. As can readily be seen, via the inlets 8, 9, coolant flows toward the impeller 20 tangentially from the outer circumference of impeller 20, and the two partial refrigerant streams are prevented from dividing wall 23 from flowing against each other prior to impingement of pump impeller 20 hold true.

Fig. 6 The drawing now shows the coolant pump 5 in a perspective and oblique view, in which case it can be seen again that the inlets 8, 9 and the outlets 10, 11 in the rotational axis of the impeller 20 are axially offset from each other, so in axial offset from each other arranged levels are located.

Finally shows Fig. 7 a sectional perspective view of the coolant pump 5 in a view obliquely from above, wherein for ease of illustration, the inlet 8 of the coolant pump 5 has been omitted. Fig. 7 serves to explain the flow conditions and shows the flow path of the coolant by means of arrows 30. The coolant enters via an inlet 9 - the second inlet 8 has been omitted due to a simplification of the drawing - in the pump housing 21 and passes through passages 27 in the impeller 20, the impeller from the suction side to the pressure side and there discharged through outlets 10, 11 to enter the cylinder inlets 12, 13 of the cylinder 2, 3.

The invention now provides a coolant pump of extremely short design in the rotational axis direction of the impeller. Due to the design of the coolant pump such that the coolant can enter the pump housing via two inlets, specifically tangentially to the outer circumference of the impeller, this axial short design of the coolant pump is achieved. In the pump chamber of the coolant pump there is an efficient mixing of the coolant sub-streams flowing in via the two inlets, and thus an efficient temperature compensation of the coolant, so that when using the cooling system according to the invention On a two-cylinder internal combustion engine, a uniform temperature balance of both cylinders is achieved.

With regard to features of the invention which are not explained in greater detail above, reference is expressly made to the claims and the drawings, moreover. <B> LIST OF REFERENCES </ b> 1 engine 21 pump housing 2 cylinder 22 pump chamber 3 cylinder 23 partition wall 4 thermostat 24 outer wall 5 Coolant pump 25 front 6 heat exchangers 26 room 7 heat exchangers 27 passage 8th inlet 28 room 9 inlet 29 hub 10 outlet 30 arrows 11 outlet 12 cylinder intake 13 cylinder intake 14 cylinder outlet 15 cylinder outlet 16 heat exchanger inlet 17 heat exchanger inlet 18 Heat exchanger outlet 19 Heat exchanger outlet 20 impeller

Claims (8)

1. A cooling system of an internal combustion engine, with two heat exchangers (6, 7) provided with a respective heat exchanger outlet (18, 19), and also a coolant pump (5) with two inlets (8, 9), which are connected in each case to a heat exchanger outlet (18, 19), and two outlets (10, 11), wherein the coolant pump (5) has a pump impeller (20) arranged rotatably in a pump chamber (22), of circular cross-section, of a pump casing (21), and the cooling system has a thermostat (4) which is formed such that in the case of heat exchangers (6, 7) through which coolant is not flowing the flow passes through only one inlet (8) and both outlets (10, 11), characterised in that the cooling system is formed such that in the case of heat exchangers (6, 7) through which coolant is flowing the flow passes through both inlets (8, 9) and both outlets (10, 11), and the inlets (8, 9) and outlets (10, 11) are formed by attachments in the form of tube pieces which extend directed away from the pump casing (21) in each case in pairs and in parallel.
2. A cooling system according to Claim 1, characterised in that the inlets (8, 9) and outlets (10, 11) are located crosswise opposite each other relative to the axis of rotation of the pump impeller (20) and are arranged offset in the direction of the axis of rotation.
3. A cooling system according to Claim 1 or Claim 2, characterised in that the inlets (8, 9) are arranged relative to the pump chamber (22) such that the coolant impinges on the pump impeller (20) tangentially from the outer periphery of the pump impeller (20).
4. A cooling system according to one of the preceding claims, characterised in that the pump chamber (22) has a partition (23) which separates the two coolant inlet streams from each other before they impinge on the pump impeller (20), which partition extends from an outer wall of the pump casing (21) in the direction of an end face (25) of the pump impeller (20).
5. A cooling system according to one of the preceding claims, characterised in that the two coolant inlet streams mix thoroughly in the pump chamber (22).
6. A cooling system according to one of the preceding claims, characterised in that the pump impeller (20) has a hub (29) formed for positive engagement with a crankshaft stump of the internal combustion engine.
7. A cooling system according to one of the preceding claims, characterised in that the pump impeller (20) has passages (27) for coolant to pass through from the inlet side of the pump chamber (22) to the outlet side.
8. A cooling system according to one of the preceding claims, characterised in that the internal combustion engine has two cylinders (2, 3) lying horizontally opposite each other.

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