The invention refers to an automotive electric liquid pump module for pumping a coolant liquid in a coolant circuit of an automobile.

Typical liquid coolant circuits in automotive applications are engine coolant circuits for an electrical traction engine or for an internal combustion traction engine, or can be traction battery coolant circuits or coolant circuits for secondary devices, for example for turbochargers, for exhaust gas valves etc. An electric liquid pump module typically comprises an electric motor directly driving a flow pump wheel defining a flow pump for relatively high volumetric pumping rates.

The cooling capacity of the coolant liquid and the pumping rate of a flow pump are substantially deteriorated by air bubbles carried with the coolant liquid current. In the state-of-the-art, an expansion tank is provided at the vertically highest point of the coolant circuit so that the air bubbles can rise up to the expansion tank. However, when the electric liquid pump is active and the coolant liquid is circulated in the coolant circuit, the air bubbles are carried with the circulating liquid current so that the air bubbles could substantially remain within the circulating liquid current and do not rise to the expansion tank.

It is an object of the invention to provide an efficient automotive electric liquid pump module.

This object is achieved with an automotive electric liquid pump module with the features of claim 1.

The automotive electric liquid pump module comprises an electric flow pump unit with a flow pump wheel directly driven by an electric motor and comprises a passive deaerator unit with a liquid inlet and with a liquid outlet. The deaerator unit is provided with a deaerator housing defining a widened deceleration chamber and also defining a deaeration opening at the vertical top of the deceleration chamber. The deceleration chamber has a cross section substantially widening from the liquid inlet to the liquid outlet so that the flow velocity of the liquid current is substantially decreased between the liquid inlet and the liquid outlet. Since the flow velocity of the liquid current within the deceleration chamber is substantially reduced, the air bubbles carried with the incoming liquid current have enough time to rise within the deceleration chamber up to the deaeration opening at the vertical top of the deceleration chamber so that the air bubbles are separated from the liquid current. The deaeration opening can be fluid ically connected to the atmosphere or to an expansion tank. A semipermeable membrane can be provided between the deaeration opening and the atmosphere or the expansion tank, the semipermeable membrane being not permeable for the coolant liquid but permeable for air.

The widening of the cross section between the liquid inlet and the liquid outlet can be realized stepwisely, for example by providing a rectangular deceleration chamber with a substantially larger cross section than the liquid inlet opening. Alternatively, the cross section can continuously increase seen in the general flow direction. Preferably, the largest crosssection within the deceleration chamber seen in the general flow direction is at least 80% larger, more preferably more than 120% larger, than the cross section of the liquid inlet opening.

The deaerator housing defining the deceleration chamber, the liquid inlet opening and the liquid outlet opening, is mechanically directly and stiffly connected to the liquid pump unit, and in particular is directly connected to a housing part of the liquid pump unit. A housing part of the liquid pump unit can be for example a housing part defining a ring channel radially surrounding the flow pump wheel.

In other words, the electrical flow pump unit and the passive deaerator unit are combined in one single integrated pump module. The fluidic properties of the flow pump unit and of the deaerator unit can be perfectly harmonized because the pump unit and the deaerator unit are fluidically directly connected to each other. Compared to a deaerator unit provided separately and remote from the pump unit, a separate connection tube and connection means to connect the two units are avoided in the integrated pump module according to the invention so that the assembly of the automotive coolant circuit is simplified and the number of fluidic interfaces is reduced.

Generally, the invention as defined in claim 1 can also be used in nonautomotive applications, for example, in a static electronics cooling circuit.

Preferably, the deaerator unit is positioned fluidically upstream of the electric flow pump unit so that a relatively air-bubble-free coolant liquid current enters the electrical flow pump unit so that the fluidic efficiency of the flow pump unit is not deteriorated and the flow pump unit always works efficiently.

Preferably, the housing main body of the deaerator housing defines the axial liquid pump inlet opening axially aligned with the center of the flow pump wheel. The axial liquid pump inlet opening is axially adjacent to the flow pump wheel. Even more preferably, the flow pump wheel is an impeller wheel and the deaerator housing main body defines an outlet ring channel, preferably a volute-like ring channel, radially surrounding the flow pump wheel. The deaerator housing main body is preferably a plastic body defining in one integral piece at least four or five side walls of the deceleration chamber and also substantially defining the outlet ring channel so that a separate (plastic) piece for defining the outlet ring channel can be avoided.

Preferably the automotive electric liquid pump module is a twin pump module and comprises a second and separate electrical flow pump unit and a second widened deceleration chamber being defined within the same deaerator unit as the first deceleration chamber. The second widened deceleration chamber is substantially separated from the first deceleration chamber so that the coolant flows flowing through the two deceleration chambers are substantially separated from each other and do not substantially mix with each other. The deaerator housing of the deaerator unit defining both deceleration chambers is mechanically directly and stiffly connected to the second flow pump unit. The liquid pump module according to this aspect of the invention therefore integrates two flow pump units as well as two deaerator means for two separate cooling liquid circuits.

Preferably, the rotational axis' of both flow pump units are provided coaxially with each other, whereas the deaerator unit is arranged axially between the two flow pump units. Since the flow pump units are provided with a motor rotor and a pump rotor both rotating relatively fast, a substantial vibration of the electrical flow pump units is unavoidable, in particular after a certain running time. With the coaxial arrangement of both flow pump units, the vibration behavior of the liquid pump module is less complex and much easier to handle compared to a configuration with a non-coaxial arrangement of the two flow pump units.

Preferably, the rotational axis' of both flow pump units intersect with the center of gravity of the liquid pump module. This dynamic configuration simplifies the dynamic and vibration behavior of the complete liquid pump module so that the fixation of the liquid pump module at that the automotive structure is simplified and more reliable. Preferably the deaerator unit is provided with a single gas outlet opening for both deceleration chambers so that the liquid pump module has only one single gas outlet opening.

One embodiment of the invention is described with reference to the enclosed drawings, wherein figure 1 shows a combined top view and a horizontal longitudinal section

I-I of an automotive electric liquid pump module according to the invention, and figure 2 shows a combined side of view and a vertical longitudinal section

II-II of the pump module of figure 1.

Figures 1 and 2 show an automotive electric liquid pump module 10 integrating two combined deaerator/pump combinations. The pump module 10 is used in an automotive application which means that low weight, very low production costs, high reliability, high vibration durability and compactness are general requirements for the pump module 10. The pump module 10 is a twin module integrating two combined flow pump unit/deaerator unit combinations in one single pump module 10. The pump module 10 can circulate a coolant liquid in two different coolant circuits, for example an automotive traction engine cooling circuit and a traction battery cooling circuit.

Figure 1 shows a top view of two different horizontal planes XY and figure 2 shows a side view of different vertical planes XZ of the pump module 10. The pump module 10 comprises a first electrical flow pump unit 20, a fluidically related first passive deaerator unit 30, a second electrical flow pump unit 20' and a fluidically related second passive deaerator unit 30'. From a structural point of view, the first deaerator unit 30 and the second deaerator unit 30' are defined by one single plastic deaerator housing 32 made of a suitable plastic deaerator housing main body 33 and a suitable cover body, so that the pump module 10 is substantially an assembly of two separate electrical flow pump units 20, 20' and the complete deaerator housing 32.

The two separate electrical flow pump units 20, 20' both have an identical structure, but alternatively can generally be different in their electric and hydraulic performance. In this embodiment, the electrical flow pump units 20, 20' both are provided with an electric can motor 24 with a separation can 25 separating a wet motor section from a dry motor section. The motor electronics 27 and an electromagnetic motor stator 29 are provided in the dry section, whereas a permanently magnetized motor rotor 28 and a flow pump wheel 22 are provided in the wet section. The motor rotor 28 directly and coaxially drives the flow pump rotor 22 which is provided as an impeller with an axial pump wheel inlet and a radial pump wheel outlet.

The deaerator housing 32 defines a first widened deceleration chamber 40 and a second identical deceleration chamber 40'. However, the two deceleration chambers 40, 40' do not necessarily need to be identical if the two connected cooling circuits and their cooling performance are not equal. The cross section area of the deceleration chambers 40, 40' is dramatically widening after the corresponding liquid inlet 38, 38' by more than 250% in relation to the cross section area of the opening of the corresponding liquid inlet 38, 38' so that the liquid entering the deceleration chamber 40, 40' is dramatically decelerated and flows relatively slowly from the liquid inlet 38, 38' to the corresponding liquid outlet 39, 39'. Therefore, the air bubbles entering the deceleration chamber 40, 40' together with the coolant liquid have much time to rise to the top region of the deceleration chamber 40, 40', as shown in figure 2. The two deceleration chambers 40, 40' are substantially separated from each other by a separation wall 44 so that the coolant liquids of the two deceleration chambers and do not mix with each other. However, both deaerator units 30, 30' have one single common deaeration opening 50 at the vertical top of the two deceleration chambers 40, 40' so that the deceleration chambers 40, 40' are fluidically connected with each other and have the same fluid pressures. Alternatively, each deaerator unit 30, 30' can have its own deaeration opening to fluidically completely separate both cooling circuits from each other.

The since the deaerator unit 30, 30' is positioned fluidically upstream of the corresponding electric flow pump unit 20, 20', the deaerator unit liquid outlet 39, 39' defines the axial liquid pump inlet opening 34, 34' so that a deaerated liquid current axially enters the corresponding pump unit 20, 20'. As can be seen in both figures, the deaerator housing main body 33 substantially defines the outer circumference wall of the outlet ring channel 26 radially surrounding the corresponding flow pump wheel 22, and also defines the corresponding tangential pump outlet duct with the corresponding pump outlet opening 302, 302'. Additionally, the deaerator housing main body 33 defines both inlet ducts 301, 301' respectively leading to the deaerator unit liquid inlets 38, 38'. The deaerator housing main body 33 is directly connected to the motor housing 24'.

As shown in both figures, the rotational axis' X, X' of both flow pump units 20, 20' are provided perfectly coaxially with each other. Additionally, the rotational axis' X, X' of both flow pump units 20, 20' perfectly intersect with the center of gravity C of the complete liquid pump module 10.