DE60122992T2 - System and method for cooling a hybrid vehicle - Google Patents

Description

The The present invention relates to a cooling device for a hybrid vehicle.

hybrid vehicles generally include a heat engine, one or two electric motors, a generator for generating electrical voltage and a unit of an electronic power converter, the either the or the electric motors feeds or charges the batteries, wherein all cooled Need to become, if under the circumstances, for the they are intended to work. It is trying this use double engine power to reduce fuel consumption and polluting Minimize exhaust gases so that they do not exceed the permissible levels.

It It has been found that the ranges for the flow rate and the Temperature of the coolant an electric motor and a heat engine are very different. The coolant an electric motor has a flow rate of about 100 to 500 l / h at a temperature of 50 to 70 °. The cooling liquid of a heat engine has a flow rate that is at a temperature of 100 to at most 110 ° that Twenty times can be. These differences in flow rate and temperature complicate the use of a single circuit and a single one cooler, in all situations encountered in a hybrid vehicle work under optimal conditions.

The FR 2 748 428 describes a cooling device for a hybrid vehicle having a heat engine and an electric motor, comprising a circulating in the engine and in a radiator coolant and means so that when the heat engine and in operation of the electric motor, the cooling liquid circulates only in a first part of the radiator and so that during operation of the two motors, the cooling liquid in the two parts of the radiator to run.

in the However, it is generally necessary to provide an electric pump around the coolant to circulate in the electric motor. The electric pumps are either very expensive or they have an insufficient life.

In the "patent Abstract of Japan "JP-2000-073763 A is described a device in which a first cooling circuit for one Cylinder head of an engine with a second cooling circuit for one Motor is connected. For An electronic power unit is a separate cooling circuit intended.

The present invention proposes before, the restrictions to fix the known techniques by using a cooling device suggests in all circumstances works optimally and with which the energy consumption as well as the polluting Exhaust gases can be reduced.

The present invention proposes before, the service life of a coolant circulation pump reduce in the electric motor.

The present invention proposes before, the electric motor and the power electronics on a low Keep temperature.

To One aspect of the invention is the cooling device for a hybrid vehicle That determines a heat engine and at least one electric motor. The facility includes a coolant for cooling the heat engine and the electric motor, a radiator with several cooling channels for cooling of the coolant through heat exchange with a stream of air, a first line between the radiator and the heat engine in flow direction of the coolant and a second conduit between the heat engine and the radiator flow direction of the coolant. The Device comprises a branch line, which has a first, with the first line connected branch and a second, with a Pipe upstream the heat engine connected branch, wherein the branch line suitable for this is to cool the electric motor.

The Device is characterized in that the first branch via a electronic power unit and the electric motor is performed.

To an embodiment of the invention is the first branch with a coolant circulation pump fitted.

To an embodiment of the invention becomes this coolant circulation pump driven by the electric motor.

To a further embodiment of the invention the coolant circulation pump is independent of driven by the electric motor.

Preferably the branch line comprises a third branch which coincides with the second Line is connected.

To an embodiment of the invention is the second branch with an output line of a heater Passenger cabin of a vehicle connected.

Preferably, the branch line comprises a fourth branch upstream of a thermostat with the output from the thermal power machine is connected.

advantageously, the branches of the branch line are connected to each other via a multi-way valve.

To an embodiment of the invention a thermostat is integrated in the multi-way valve.

To an embodiment of the invention the multiway valve comprises a rotatable control core.

The The invention also relates to a vehicle comprising a cooling device, as described at the beginning.

The Invention proposes also a cooling process for a Hybrid vehicle comprising a heat engine and at least one electric motor, which by circulation of a coolant cooled in the engines be a heat exchange agent, a first line between the radiator and the heat engine in the flow direction of the coolant and a second conduit between the heat engine and the heat exchange means in the flow direction the coolant, in which method for cooling the electric motor and the electronic power unit the coolant guided in a branch line which is on the one hand with the first line and on the other hand with an upstream the heat engine connected line is connected.

Consequently the cooling takes place serial, with the coolant flows through the branch line, then into the heat engine what happens at high temperature at the exit of the heat exchange medium is preferable.

advantageously, is the flow rate of the coolant in the branch line depending the temperature at the outlet of the heat exchange medium mutable.

To an embodiment of the invention if the temperature of the coolant increases is low to the arranged at the output of the heat engine To open thermostat, the coolant guided in the branch line, the third is connected to the second line, so as to the electric motor to cool, when in the heat engine no coolant flows. These Mode of operation can also be selected when the heat engine is at a standstill.

To an embodiment of the invention is, if the temperature of the coolant significantly Below the temperature, which is required to a on Output of the heat engine arranged To open thermostat, the coolant in the branch line out, the fourth with the output of the heat engine upstream of the Thermostat is connected, so as to cool the electric motor and at the same time the heat engine to heat. Thus, the temperature of the heat engine at startup increase faster and reduce the formation of environmentally harmful elements become.

These Mode of operation can also be selected when the heat engine at rest, when the heat engine assigned Pump is driven electrically or when the pump is bypassed can. In this way, the heat engine can be preheated.

The The invention will become apparent from the following detailed description some non-limiting to be understood embodiments, the in the attached Drawings are shown, closer explains which also results in further advantages. Show it:

1 a cooling device according to a first embodiment of the invention in a schematic view;

2 an example of a multi-way valve in a schematic view, in axial section;

3 the multi-way valve after 2 in a schematic cross-sectional view;

4 a multi-way valve integrated in a thermostat in a schematic cross-sectional view; and

5 another embodiment of the cooling device in a schematic view.

Of the For simplicity, in our description, the term "electric motor" refers to all machines, the electrical energy into mechanical energy or mechanical Converting energy into electrical energy, and the term "power electronics" means any electronics, the alternating current into direct current or direct current into alternating current, High-voltage current in low-voltage current or low-voltage current converted into high voltage power.

As in 1 can be seen, is the cooling device of a heat engine 1 and one with an electronic power unit 3 provided electric motor 2 assigned. This electronic power unit 3 is generally the electric motor 2 upstream, because their operating temperature is lower is than that of the electric motor. Also provided are a heater 4 for heating the passenger cabin in which the cooling device is mounted, and a heat exchanger 5 for cooling any medium, such as lubricating oil, gear oil, ..., or any component, such as a bearing for a turbocharger, ....

The cooling device comprises a cooler 6 whose output is connected to a line 7 and its entrance with a pipe 8th connected is. The administration 7 is on a pump 9 connected, whose output with the heat engine 1 connected is. The pump 9 can through the heat engine 1 or driven by an electric motor, not shown, assigned to it. The output of the engine 1 is with a thermostat 10 provided, in turn, with the line 8th connected is. The cooler 6 is generally with a motorized fan 11 provided with which the air flow through the radiator 6 can be accelerated.

The cooling device comprises a temperature sensor 12 , at the output of the engine 1 directly above the thermostat 10 is arranged, a temperature sensor 13 who is on the line 7 at the exit of the cooler 6 is mounted, and a control unit 14 that of the feelers 12 and 13 incoming temperature data receives. The connection between the control unit 14 and the feelers 12 and 13 can be made by dedicated electrical wires or via a communication bus.

The entrance of the heater 4 is with an output of the heat engine 1 and the output of the heater 4 , with the guidance 7 connected. Likewise, the entrance of the heat exchanger 5 with an output of the heat engine 1 and his exit with the pipe 7 connected.

The cooling device also comprises a total of 15 designated branch line, with several branches and a multi-way valve 16 to which these branches are connected.

In detail is a first branch 17 on the one hand with the line 7 downstream of the temperature sensor 13 and on the other hand with the multi-way valve 16 connected. The branch 17 is by the electric motor 2 and by the electronic power unit 3 carried out. By that in this branch 17 flowing coolant become the electric motor 2 and the electronic power unit 3 maintained at a normal operating temperature, which is as low as possible so that common industrial components, both electrical and electronic, can be used for the construction of this element.

In addition, one is on the branch 7 arranged electric pump 21 provided by the control unit 14 is controlled and the coolant in the branch 17 circulating. A second branch 18 is with one end to the first line 7 near the pump 9 and at its opposite end with the multiway valve 16 connected.

A third branch 19 is on the one hand with the line 8th and on the other hand with the multi-way valve 16 connected. A fourth branch 20 is on the one hand with an output of the heat engine 1 upstream of the thermostat 10 and on the other hand with the multi-way valve 16 connected. With the multi-way valve 16 can on command of the control unit 14 to which this is connected, the branches 17 and 18 by closing the branches 19 and 20 , the branches 17 and 19 by closing the other branches and the branches 17 and 20 be connected by closing the other branches with each other.

In other words, the task of the multi-way valve 16 , which has four ways here, in it, the targeted flow of coolant between the branch 17 and one of the other branches 18 . 19 respectively. 20 sure.

The cooling device works as follows. Is that from the feeler 12 measured water temperature below a predetermined temperature T _c1 , which is less than or equal to the temperature T _ot at which the thermostat 10 opens and generally in the range between 83 and 89 ° C, so connects the multi-way valve 16 the branches 17 and 20 among themselves and clears the way, so that in operation of the heat engine 1 the means of the branch 20 to the branch 17 can get. The coolant that is in the heat engine 1 is because of the pump 9 exposed to a high pressure that is higher than that in the branch 17 prevails as the pump 21 is held at a standstill.

In this state, which is the starting operating state or the state of very low load of the heat engine 1 is from the pump at standstill 21 no energy consumed. By the heat generated by the operation of the electric motor 2 and the electronic power unit 3 is discharged, the temperature of the heat engine can 1 increases, and thus the duration of the temperature rise can be reduced, which is a reduction in the amount of by the combustion of the heat engine 1 produced polluting elements result. By the pump 21 is kept at a standstill, their overall service life is reduced, thereby prolonging their overall life.

If the feeler 12 indicates a water temperature higher than or equal to the temperature T _c1 but lower than the temperature T _ot at which the thermo stat 10 opens, so the multi-way valve 16 a connection between the branches 17 and 19 ago. The pump 21 is then put into operation at low speed, for example at a low supply voltage U ₁ . The electric motor 2 and the electronic power unit 3 then by means of the cooler 6 cooled, whose heat exchange capacity is much larger, for example, by a factor of about 3 to 5, as the heat, possibly from the electric motor 2 and the electronic power unit 3 is delivered. Because the line 8th , the cooler 6 and the line 7 for those of the heat engine 1 required high flow rates of the coolant are dimensioned, the charge losses are low. Thus, that of the pump 21 consumed energy low. Their consumption is also low.

Gives the feeler 12 a water temperature which is higher than or equal to the temperature T _ot , so does the multi-way valve 16 a connection between the branches 17 and 18 ago. The pump 21 is put into operation. In other words, part of the amount that comes out of the cooler 6 emanates, over the branches 17 and 18 diverted. The electric motor 2 and the electronic power unit 3 be through from the radiator 6 coming coolant cooled, thus at low temperature.

In addition, it can be provided that when the temperature sensor 13 at the exit of the cooler 6 indicates a temperature of the coolant that is less than a predetermined temperature T _c2 , the pump 21 with a low flow rate, for example, at the low supply voltage U ₁ , works, and in contrast, when the sensor 13 indicates a temperature which is higher than the temperature T _c2 , the pump 21 operates at a high flow rate and is supplied, for example, with a voltage U ₂ , which is higher than U ₁ to in the branch 17 to achieve a higher flow rate. It is understood that T _{c2 is} higher than T _ot .

It is understood that the control unit 14 the cooling device the operation of the fan 11 depending on the sensor 13 can control measured temperature.

Is the heat engine 1 at standstill, so does the multiway valve 16 a connection between the branches 17 and 19 ago. The pump 21 is put into operation at low flow, for example, by being supplied with the voltage U ₁ . The cooler 6 then ensures the cooling of the electric motor 2 and the electronic power unit 3 which can be operated at the low temperatures required for the mass-produced low-cost components that one wishes to use.

The water temperature at the entrance of the electric motor 2 and the electronic power unit 3 thus remains very low in all modes. Measurements made on a prototype show that even if the heat engine 1 is in operation and the water temperature at the output of the engine is higher than the temperature T _ot , at which the thermostat opens, but the temperature remains at the outlet of the radiator 6 in 85% of the life of the vehicle below 85 ° C. In the cases where the of the feeler 13 measured temperature exceeds T _c2 , this temperature can be kept within the desired limits by adjusting the delivery rate of the pump 21 increased and / or the fan 11 is turned on.

Thanks to the invention requires the pump 21 a low power, it turns slower and less often. In an operating case, the pump is located 18 at standstill. In two other operating cases where the thermostat is closed, the heat exchange capability of the radiator is 6 responsible for the heat losses of the heat engine 1 is measured, for the heat losses of the electric motor 2 and the electronic power unit 3 far enough, so the pump 21 can be operated at low power. Finally, the branches 17 . 18 and 19 with the large diameter pipes 7 and 8th connected, so that the charge loss, that of the pump 21 subsidized funds is minimized.

The 2 and 3 provide an example of a valve 16 dar. The valve 16 includes a cylindrical housing 22 and a rotatable core 23 that is under the action of an electric motor 25 around the axis 24 can turn. On a so-called "lower" level is the case 22 provided with a bore into which the branch 17 empties. On a so-called "higher" level, which is offset to the lower level, is the housing 22 provided with three holes in each of the branches 18 . 19 respectively. 20 open out. The core 23 includes a Z-shaped channel 26 for the agent and an outer annular cavity 27 , The annular cavity 27 is independent of the angular position of the core 23 with the branch 17 in connection. The annular cavity 27 stands with the channel 26 in connection.

In a variant, it could be provided that the channel 26 for the agent is in the form of a C or other shapes which cause a smoother change in the direction of flow so as to reduce the pressure loss of the agent. Due to the effect of the electric motor 25 can the core 23 occupy three angular positions, leaving the channel 26 opposite one of the branches 18 . 19 respectively. 20 lies to the particular connection between the branches 17 and 18 . 17 and 19 respectively. 17 and 20 manufacture. From any initial state of the core 23 can be changed immediately from one state to another, without going through any other intermediate state than that of the complete closure. The change between the states is done by simply turning the core 23 120 ° in one direction or the other.

4 represents a particularly compact variant in which it is proposed, the valve 16 in the thermostat 10 to integrate. The thermostat 10 includes a mounting plate 28 at the engine, leaving the entrance 29 of the thermostat 10 with an outlet for the coolant from the heat engine 1 out 1 connected is. The thermostat 10 includes an exit 30 which is intended to be connected to the line 8th of the 1 to be connected, and an exit 31 which is intended to work with the heater 4 and the heat exchanger 5 out 1 to be connected. entrance 29 and exit 31 are in free connection. Between entrance 29 and exit 30 is one by a spring 33 operated flap 32 intended. At a low temperature, which is less than T _ot , holds the spring 33 the flap 32 in the closed position, so that the coolant is no longer as in 1 from the heat engine 1 to the radiator 6 can flow.

The flap 32 is at a bar 34 attached, whose free end is immersed in a mixture of wax and copper particles, which in a small, called "tuber" and with 35 container is included, which is on the frame of the thermostat 10 is attached. The tuber 35 is constantly lapped by the coolant from the heat engine to the output 31 flows. At a temperature below T _ot is that in the tuber 35 contained mixture in the solid state. When the temperature of the coolant rises, it liquefies in the tuber 35 contained mixture and expands so far that they shut the flap 32 imprints, making the way from the entrance 29 to the exit 30 is opened.

It is intended that the branch 19 of the valve 16 immediately at the exit 30 flows and that branch 20 near the tuber 35 flows into the room in which he is housed and in which the coolant between the entrance 29 and exit 31 flows.

The 5 shows a cooling device, which is an integrated thermostat 10 and an integrated valve 16 includes. With its end, that's the valve 16 is opposite, is the branch 18 with the line section 36 connected to the heater 4 and the line 7 combines. Thus, the length of the branch 18 be reduced, thereby saving costs.

Next up, it was assumed that the pump 21 is driven by an independent electric motor. It is also conceivable that the pump 21 through the electric drive motor 2 is driven. This is beneficial for both the cost and the life of the device. A known electric pump generally works with direct current. Compared to a mechanical pump, the electric motor is the main cost factor in an electric pump and generally has a life that is significantly less than that of the mechanical pump. In this case, the device works as follows.

Is that from the feeler 12 measured water temperature below the temperature T _ot , at which the thermostat opens, then the branches become 17 and 19 connected. Is that from the feeler 12 measured water temperature is higher than or equal to the temperature T _ot , and the vehicle is at a standstill heat engine 1 electrically driven, so does the flow connection between the branches 17 and 19 maintained. Is that from the feeler 12 measured temperature of the coolant higher than or equal to the temperature T _ot and is the heat engine in operation, so does the valve 16 the connection between the branches 17 and 18 ago. Also measures the feeler 13 a temperature higher than the predetermined temperature T _c2 , then the fan 11 in particular set in operation when the vehicle speed is low, for example, below a value in the range between 60 and 80 km / h.

It should be noted that in the case where the pump 21 from the engine 2 is driven, the medium does not need to flow from 20 to 17, as was provided in the hybrid mode, to the use of the pump 21 to reduce, and that the valve 16 then it can be a 3-way valve.

Claims (10)

Cooling device for a heat engine ( 1 ) and at least one electric motor ( 2 ) comprising a hybrid vehicle, comprising a coolant for cooling the heat engine and the electric motor, a radiator ( 6 ) with a plurality of cooling channels for cooling the coolant by heat exchange with an air flow, a first line ( 7 ) between the radiator and the heat engine in the flow direction of the coolant and a second line ( 8th ) between the heat engine and the radiator in the flow direction of the coolant, further comprising a branch line ( 15 ), which has a first branch connected to the first line ( 17 ) and a second branch connected to a line upstream of the heat engine ( 18 ), wherein the branch line is adapted to the electric motor ( 2 ) to cool, characterized in that the first branch is connected via an electronic power unit ( 3 ) and the electric motor ( 2 ) to be led. Device according to claim 1, characterized in that the first branch with a coolant circulation pump ( 21 ) Is provided. Device according to one of the preceding claims, characterized in that the branch line comprises a third branch ( 19 ) connected to the second line. Device according to one of the preceding claims, characterized in that the second branch with an output line of a heater ( 4 ) is connected to a passenger cabin of a vehicle. Device according to one of the preceding claims, characterized in that the branch line comprises a fourth branch ( 20 ) upstream of a thermostat ( 10 ) is connected to the output from the heat engine. Device according to one of the preceding claims, characterized in that the branches of the branch line via a multi-way valve ( 16 ) are interconnected. Device according to claim 6, characterized that a thermostat is integrated in the multi-way valve. Device according to claim 6 or 7, characterized in that the multiway valve has a rotatable control core ( 23 ). Vehicle comprising a device according to one of preceding claims. A cooling method for a hybrid vehicle, comprising a heat engine and at least one electric motor cooled by circulation of a coolant in the engines, a heat exchange means, a first conduit between the radiator and the heat engine in the flow direction of the coolant, and a second conduit between the heat engine and the radiator in the flow direction of the coolant, in which, for cooling the electric motor, the coolant is conducted in a branch line which is connected on the one hand to the first line and on the other hand to a line located upstream of the heat engine, and wherein an electronic power unit ( 3 ) in front of the electric motor ( 2 ) in the branch line ( 15 ) is arranged.