EP1362168B1 - Device, system and method for cooling a coolant - Google Patents

Description

The present invention relates to a cooling system for a hybrid-propulsion vehicle.

Hybrid-propulsion vehicles generally include a heat engine, one or two electric motors, a voltage generator, and an electronic power converter assembly that powers the one or more electric motors, or charges the batteries, all of which must be cooled. in order to function under the conditions for which they are intended. We seek to take advantage of this dual engine to minimize consumption and polluting emissions, so as to remain below the authorized levels.

It has been found that the flow and temperature ranges of the coolant are very different for an electric motor and for a heat engine. The coolant of an electric motor has a flow rate of the order of 100 to 500 l / hour at a temperature of 50 to 70 °. The coolant of a heat engine has a flow rate that can be twenty times higher, at a temperature of the order of 100 to 110 ° maximum. These differences in flow and temperature make it difficult to use a single circuit and a single radiator operating under optimum conditions on all the situations encountered for a hybrid-propulsion vehicle.

The document FR 2 748 428 (RENAULT) describes a cooling system for a hybrid-propulsion vehicle comprising a heat engine and an electric motor, comprising a liquid coolant circulating in the engines and in a radiator and means that, with the engine stopped and the electric motor running, the heat transfer liquid circulates in a first part of the radiator only, and so that both engines being in operation, the coolant circulates in both parts of the radiator.

However, when both engines are running, the electric motor passes a coolant at relatively high temperature.

Japanese Abstract 10 266 855 (TOYOTA) discloses a cooling system comprising a radiator, an expansion vessel common to a circuit dedicated to the heat engine and a circuit dedicated to the electric motor. The radiator comprises two inlets and two outlets connected to two water boxes, one of which is divided by a partition. The other water box is devoid of partition and the two circuits are in communication via it. During operation, the water in both circuits will hardly mix.

However, the heat generated by the electric motor can not be used to heat or preheat the engine or the cabin of the vehicle. The electric motor circuit pump operates as long as the electric motor is in operation which reduces the life of said pump. When the electric motor is not in use, the radiator dedicated to it is useless and does not benefit the cooling of the engine and vice versa when the engine is not in use, the radiator dedicated to him does not is useless and does not benefit the cooling of the electric motor.

The publication DE 196 817 describes a device for cooling the heat transfer fluid by heat exchange with another fluid comprising an inlet and a main heat transfer fluid outlet, and an auxiliary outlet whose fluid is at a temperature below that of the outlet. main.

The present invention proposes to overcome the limitations of conventional techniques by providing a device and a cooling system operating optimally in all cases and to reduce energy consumption and polluting emissions.

The present invention proposes to reduce the operating time of a coolant circulation pump in the electric motor.

The present invention proposes to keep the electric motor at a low temperature.

For this purpose, it proposes a cooling system for a hybrid-propulsion vehicle comprising a heat engine and at least one electric motor. The system is of the type comprising a coolant capable of cooling the thermal and electrical engines, a radiator capable of cooling the heat transfer fluid by heat exchange with a stream of air and comprising a plurality of cooling channels, an inlet and an outlet, a first pipe between the radiator outlet and the heat engine and a second pipe between said heat engine and the radiator inlet. The radiator comprises an auxiliary output so that the heat transfer fluid from the auxiliary output is a temperature lower than that of the main output connected to the first pipe, said auxiliary output being connected to a bypass pipe suitable for cooling the electric motor.

Preferably, the bypass line comprises a first branch connected to the auxiliary output and a second branch connected to a pipe upstream of the heat engine.

Preferably, the first branch is able to be connected to the first conduit.

The first branch can go through the electric motor and an electronic power unit of the electric motor.

The first branch can be equipped with a coolant circulation pump.

In one embodiment of the invention, the second branch is connected to an output pipe of a heating radiator of a vehicle passenger compartment.

In one embodiment of the invention, the bypass line comprises a third branch connected to the second conduit.

In one embodiment of the invention, the bypass line comprises a fourth branch connected to the output of the heat engine upstream of a thermostat.

In one embodiment of the invention, branches of the branch line are interconnected by a multi-way valve. A thermostat can be integrated with said multi-way valve. The multi-way valve may include a rotary control core.

In one embodiment of the invention, said coolant circulation pump is driven by the electric motor.

In another embodiment of the invention, said coolant circulation pump is driven independently of the electric motor.

In a preferred embodiment of the invention, the system comprises a thermostat disposed on the first pipe, the thermostat being able to close the first pipe, a pipe connected to the electric motor being able to be in communication with the heat engine.

In one embodiment of the invention, the system comprises a first valve adapted to put the output of the electric motor at least in communication with the heat engine.

In one embodiment of the invention, the first valve is of multichannel type and is able to put the output of the electric motor into communication with the heat engine or with the second pipe.

In one embodiment of the invention, the system comprises a second valve adapted to put the auxiliary output at least in communication with the electric motor.

In one embodiment of the invention, the second valve is multi-port type and is able to put the auxiliary output in communication with the electric motor or with the heat engine.

In one embodiment of the invention, the electric motor is mounted on a bypass line parallel to the heat engine.

In one embodiment of the invention, said auxiliary output is connected to a branch line capable of cooling an electronic control unit.

The invention also relates to a vehicle comprising a cooling system as above.

The invention also proposes a cooling method for a hybrid-propulsion vehicle comprising a heat engine and at least one electric motor cooled by the circulation of a coolant in said engines, a heat exchange means capable of cooling the coolant by heat exchange with another fluid and provided with an inlet and an outlet, in which process the flow of heat transfer fluid is divided in the heat exchange means between a main output and an auxiliary outlet so that the heat transfer fluid from the auxiliary output has a temperature lower than that of the main output, said auxiliary output being connected to a bypass line suitable for cooling the electric motor.

The cooling can be carried out in series, the fluid coolant passing in the bypass line then passing into the engine which is preferable in case of high temperature output of the heat exchange means.

Advantageously, the coolant flow rate in the bypass pipe is varied as a function of the temperature at the outlet of the heat exchange means.

In one embodiment of the invention, in the event of a temperature of the coolant insufficient to cause the opening of a thermostat disposed at the output of the heat engine, the heat transfer fluid is circulated in the bypass line connected thirdly to the input of the heat exchange means for cooling the electric motor in the absence of heat transfer fluid circulation in the engine. This mode of operation can also be adopted when the heat engine is stopped.

In one embodiment of the invention, in the event of a temperature of the coolant significantly lower than the opening temperature of a thermostat disposed at the output of the heat engine, the heat transfer fluid is circulated in the fourth connected branch line. part at the output of the engine upstream of the thermostat, to cool the electric motor while warming the engine. It is thus possible to obtain a faster temperature rise of the engine during its start and reduce the formation of pollutants.

This mode of operation can also be adopted when the heat engine is stopped, if the pump associated with the heat engine is electrically driven or if said pump can be bypassed. It can thus preheat the engine.

• la figure 1 est une vue schématique d'un système de refroidissement selon un mode de réalisation de l'invention;
• la figure 2 est une vue schématique d'un radiateur;
• les figures 3 à 8 et 10 à 16 sont des vues schématiques d'un système de refroidissement selon d'autres modes de réalisation de l'invention;
• la figure 9 est une vue schématique d'un autre radiateur; et
• la figure 17 est une schématique d'une vanne.

The invention will be better understood and other advantages will appear on reading the detailed description of some embodiments taken as non-limiting examples and illustrated by the appended drawings, in which:

• Figure 1 is a schematic view of a cooling system according to one embodiment of the invention;
• Figure 2 is a schematic view of a radiator;
• Figures 3 to 8 and 10 to 16 are schematic views of a cooling system according to other embodiments of the invention;
• Figure 9 is a schematic view of another radiator; and
• Figure 17 is a schematic of a valve.

To simplify our description, the term "electric motor" defines all machines that convert electrical energy into mechanical energy, or mechanical energy into electrical energy, and the term "power electronics" defines all electronics that convert alternating current into direct current, direct current into alternating current, high voltage current into low voltage current, or low voltage current into high voltage current.

As can be seen in FIG. 1, the cooling system is associated with a heat engine 1 and with an electric motor 2 provided with an electronic power unit 3. There is also provided a heating radiator 4 for heating the heat. the passenger compartment of the vehicle in which the cooling system is installed, as well as an exchanger 5 for cooling any fluid, for example the lubricating oil, the gearbox oil, ... or any other organ, for example a turbocharger bearing, ...

The cooling system comprises a radiator 6 of which a main output 6a is connected to a pipe 7 and whose input is connected to a pipe 8. The pipe 7 is connected to a pump 9 whose output is connected to the heat engine 1. The pump 9 can be driven by the heat engine 1 or by an electric motor which is dedicated to it and which has not been shown. The output of the engine 1 is provided with a thermostat 10, itself connected to the pipe 8. The radiator 6 is generally provided with a motorized fan 11, able to accelerate the flow of air through said radiator 6 .

The cooling system comprises a temperature sensor 12 disposed at the output of the engine 1, immediately upstream of the thermostat 10, a temperature sensor 13 mounted on the pipe 7 at the outlet of the radiator 6, and a control unit 14. receiving temperature information from the sensors 12 and 13. The connection between the control unit 14 and the sensors 12 and 13 can be effected by dedicated electrical wires or via a communication bus.

The inlet of the heating radiator 4 is connected to an output of the heat engine 1 and the output of the radiator 4 is connected to the pipe 7. Similarly, the inlet of the heat exchanger 5 is connected to an output of the heat engine 1 and its output is connected to line 7.

The cooling system further comprises a generally referenced branch line 15 provided with a plurality of branches, and a multi-way valve 16 to which said branches are connected.

More specifically, a first branch 17 is connected, on the one hand to an auxiliary output 6b of the radiator 6 and on the other hand to the multi-way valve 16. The branch 17 passes through the electric motor 2 and the unit 3. The circulation of the cooling fluid in said branch 17 makes it possible to maintain the electric motor 2 and the power unit 3 at a normal operating temperature, if possible low enough so that current industrial components, both electrical and electronic devices, can be used in the construction of these elements.

There is further provided an electric pump 21 disposed on the branch 7, controlled by the control unit 14 and circulating the cooling fluid in said branch 17. A second branch 18 is connected at one end to the first pipe 7 to near the pump 9 and at the end opposite the multi-way valve 16.

A third branch 19 is connected, on the one hand to the pipe 8 and on the other hand to the multi-way valve 16. A fourth branch 20 is connected, on the one hand, to an output of the heat engine 1 upstream of the thermostat 10 and on the other hand to the multi-way valve 16. The multi-way valve 16 is adapted to put in communication the branches 17 and 18 by closing the branches 19 and 20, to put in communication the branches 17 and 19 closing off the other branches and placing the branches 17 and 20 in communication by closing off the other branches, and this by order of the control unit 14 to which it is connected.

In other words, the multi-way valve 16, which is here four-way, has the function of ensuring the selective passage of the cooling fluid between the branch 17 and one of the other three branches 18, 19 or 20 .

In addition, the bypass line 15 comprises a fifth branch 22 and a 3-way valve 23. The valve 23 is mounted on the branch 17 near the outlet 6b of the radiator 6, in other words between the outlet 6b and the pump 21. The fifth branch 22 is connected, on the one hand to the valve 23 and, on the other hand to the pipe 7 downstream of the temperature sensor 13.

The structure of the radiator 6 is illustrated in more detail in FIG. 2. The radiator 6 comprises a plurality of parallel pipes and two water boxes 24 and 25 into which the ends of the pipes open. The water box 24 is divided into an upstream portion 24a and a downstream portion 24b by a partition 26 forming a tight separation. The upstream portion 24a is connected to an inlet 27 of the radiator 6. The downstream portion 24b is connected to the main outlet 6a.

The water box 25 is divided into an upstream part 25a and a downstream part 25b by a partition 28 forming a tight separation. The upstream portion 25a communicates tubings connected to the upstream portion 24a and tubing connected to the downstream portion 24b. The radiator 6 is said to U-shaped circulation, the upstream portion 25a forming the bottom of the U. The downstream portion 25b is connected to the auxiliary output 6b. The downstream portion 24b communicates tubings connected to the upstream portion 25a and tubing connected to the downstream portion 25b.

The cooling fluid passes through the radiator 6, a first pass from the upstream portion 24a of the water box 24 to the upstream portion 25a of the water box 25, then a second pass of the upstream portion 25a of the box 25 to the downstream portion 24b of the water box 24 and is divided into two streams one passing through the main outlet 6a, the other performing a third pass from the downstream portion 24b of the water box 24 to the downstream part 25b of the water box 25. Said other stream benefits from a heat exchange of longer duration and leaves the radiator 6 at a lower temperature than the flow through the main exit 6a. In some cases one of the streams may be zero. It is therefore possible to maintain the electric motor 2 and the power unit 3 at a low temperature which makes it possible to use large-scale industrial components at low cost.

The operation of the cooling system is as follows.

1) Engine 1 running.

If the temperature of the water as measured by the sensor 12, is lower than a predetermined temperature T _c1 and which is less than or equal to the temperature T _ot of the thermostat opening 10, generally between 83 and 89 ° C, the multi-way valve 16 communicates the branches 17 and 20 and allows to pass the fluid from the branch 20 to the branch 17. The pump 21 is stopped. The cooling fluid which is in the heat engine 1 is subjected to a high pressure due to the pump 9, higher pressure than that prevailing in the branch 17. The valve 23 communicates the branches 17 and 22 and allows to leave passing the fluid from the branch 17 to the branch 22. The valve 23 intersects the outlet 6b.

In this state, which is that of a running operation of the heat engine 1 or very low load, no energy is consumed by the pump 21 which is at a standstill. The heat generated by the operation of the electric motor 2 and the power unit 3 makes it possible to increase the temperature of the heat engine 1 and thus to reduce the duration of its rise in temperature, which is reflected in the reduction in the quantity of polluting elements generated by the combustion of the heat engine 1. The stopping of the pump 21 reduces its operating time and thus allows a longer overall service life.

If the sensor 12 indicates a water temperature greater than or equal to the temperature _Tc1 but lower than the temperature T _ot of the thermostat opening 10, the multi-way valve 16 communicates the branches 17 and 19. The pump 21 is started at low speed, for example with a low supply voltage U ₁ . The valve 16 is maintained as before or on the contrary cut the branch 22 and opens the outlet 6b. The electric motor 2 and its power unit 3 are then cooled by means of the radiator 6, the heat exchange capacity of which is much greater, for example by a factor of the order of 3 to 5, at the heat likely to be cleared by the electric motor 2 and its power unit 3. The pipe 8, the radiator 6 and the pipe 7 being sized for the high flow rates of cooling fluid required by the heat engine 1, the pressure losses are low. The energy consumed by the pump 21 is therefore also low. Its wear is too.

If the sensor 12 indicates a water temperature greater than or equal to the temperature T _ot , the multi-way valve 16 communicates the branches 17 and 18. The pump 21 is turned on. The valve 23 intersects the branch 22 and opens the outlet 6b.

In other words, the flow rate of the output 6b of the radiator 6 passes through the branches 17 and 18. The electric motor 2 and its power unit 3 are cooled by coolant at low temperature.

In addition, it can be provided that if the temperature sensor 13 at the radiator output 6 indicates a coolant temperature lower than a predetermined temperature T _c2 , the pump 21 operates at a low flow rate, for example with the low voltage of supply U ₁ , and that against if the sensor 13 indicates a temperature above the temperature T _c2 , the pump 21 operates at a high rate, for example powered by a voltage U ₂ greater than U ₁ to obtain a higher rate in the branch 17. It will be understood that T _c2 is greater than T _ot .

Of course, the control unit 14 of the cooling system can control the operation of the fan 11 as a function of the temperature measured by the sensor 13.

2) Engine 1 stopped, all-electric vehicle.

If the temperature of the water measured by the sensor 12 is lower than the temperature T _c1 , the multi-way valve 16 communicates the branches 17 and 20 and allows to pass the fluid from the branch 17 to the branch 20 The valve 23 communicates the branches 17 and 22 and allows to pass the fluid from the branch 22 to the branch 17. The valve 23 intersects the outlet 6b. The pump 21 is started at low flow, for example powered by the voltage U ₁ . It is thus possible to heat the heat engine 1 and, if necessary, the passenger compartment by the radiator 4.

If the temperature of the water measured by the sensor 12, is greater than the temperature T _c1 , the multi-way valve 16 communicates the branches 17 and 19 and allows to pass the fluid from the branch 17 to the branch 19 The valve 23 intersects the branch 22 and opens the outlet 6b. The pump 21 is started at low flow, for example powered by the voltage U ₁ . This mode allows excellent cooling of the electric motor 2 and the power unit 3 because the cooling fluid passes through the entire radiator 6 (three passes).

It is also possible to obtain an intermediate cooling performance by only passing the water through the third pass of the radiator 6 by means of the multichannel valve 16 which puts in communication the branches 17 and 18. This intermediate configuration can be of interest for to reduce the possible oscillation of the temperature of the water during the transition from the temperature rise phase and heating to the super cooling phase described above.

If the sensor 13 indicates a temperature higher than the temperature T _c2 , the fan 11 is started, however, this will only rarely occur or a reduction in the operating time of said fan 11 and a reduction in the power consumption. 'energy.

3) Electric motor 2 stopped, without the need for cooling of electronic components.

The pump 21 can be started to pass cooling fluid in the third pass and thus provide additional cooling of the engine. The valve 16 communicates the branches 17 and 18. The valve 23 communicates the branch 17 with the outlet 6b and closes the branch 22.

Alternatively, it can be provided to maintain the pump 21 to stopping and communicating the branch 22 with the output 6b and while closing the branch 17 by means of the valve 16.

Thus, the water temperature at the inlet of the electric motor 2 and the electronic power unit 3 remains very low in all cases of operation. For cases where the temperature measured by the sensor 13 is greater than T _c2 , an increase in the flow rate of the pump 21 and / or the triggering of the fan 11 can maintain this temperature within the desired limits.

Thanks to the invention, the pump 21 needs a low power, runs slower and less frequently. In one operating case, the pump 21 is at a standstill. In two other operating cases where the thermostat is closed, the heat exchange capacity of the radiator 6, sized for thermal losses of the heat engine 1, is largely in excess of the thermal losses of the electric motor 2 and the electronic unit. of power 3 and thus allows the pump 21 to operate at low flow. Finally, the branches 17, 18 and 19 are connected to pipes 7 and 8 of large diameter, which minimizes the pressure drop experienced by the fluid driven by the pump 21.

It has been assumed above that the pump 21 is driven by an independent electric motor. It is also conceivable that the pump 21 is driven by the electric traction motor 2. This is advantageous for the cost and the lifetime of the system. Indeed, a conventional electric pump is generally DC. Compared to a mechanical pump, the electric motor is the main additional cost of an electric pump and generally has a life significantly lower than that of the mechanical pump. The operation of the system is then the following.

If the water temperature measured by the sensor 12 is lower than the thermostat opening temperature T _ot , the branches 17 and 19 are put into communication. If the water temperature measured by the sensor 12 is greater than or equal to the temperature T _ot , and if the vehicle is in electric traction mode, with the engine 1 stopped, the fluid communication between the branches 17 is maintained. and 19. If the coolant temperature measured by the sensor 12 becomes greater than or equal to the temperature T _ot and if the engine is in operation, the valve 16 establishes communication between the branches 17 and 18. Further, if the sensor 13 measures a temperature higher than the predetermined temperature T _c2 the fan 11 is activated, especially if the speed of the vehicle is low, for example less than a value between 60 and 80 km / h.

FIG. 3 illustrates a variant in which the electric motor 2 and the electronic power unit 3 are cooled in parallel, the branch 17 dividing into a sub-branch 17a passing through the electric motor 2 and into a sub-branch. branch 17b passing through the electronic power unit 3.

In Figure 4, there is illustrated a variant in which the valve 23 and the branch 22 are removed. The branch 17 is permanently in communication with the output 6b. This economical variant is interesting if the heating of the heat engine 1 is not a priority.

In Figure 5, is shown a variant close to the previous except that the branch 20 is removed. The valve 16 is three-way. This economical variant is advantageous if the heating of the heat engine 1 is not a priority and if the life of the pump 21 is not critical, for example if the pump 21 is driven by the electric motor 2.

In Figure 6, is shown a variant similar to that of Figure 1. The radiator 6 is of two-pass type with a water box 24 without partition. The coolant passes between inlet 27 and outlet 6a.

In Figure 7, is shown a variant similar to that of Figure 5 except that the branch 19 and the valve 16 are deleted. When the thermostat 10 is closed with the pump 21 running and for certain speeds of the heat engine 1, the cooling fluid from the radiator 4 and the heat exchanger 5 can enter through the outlet 6a of the radiator 6, make a pass, and exit through exit 6b. The cooling fluid from the branch 18 can pass through the pump 9 and the heat engine 1.

In FIG. 8, a variant similar to that of FIG. 7 is illustrated, except that the branch 18 is connected to the pipe 7 closer to the outlet 6a, in other words between the sensor 13 and the branch to the exchanger 5.

FIG. 9 shows a radiator variant similar to that of FIG. 2, except that the water box 24 is divided into three upstream parts 24a, 24b central and 24c downstream by partitions 26 and 29. downstream portion 24c is connected to the auxiliary output 6b. The downstream portion 25b of the water box 25 communicates tubings connected to the central portion 24b and tubing connected to the downstream portion 24c. The radiator 6 is said to four passes with circulation in double U. We obtain a temperature at the auxiliary output 6b even lower.

The main outlet 6a can be provided for a current operation at around 90 to 105 ° C, the desired temperature for the heat engine, without the risk of overconsumption of fuel due to a too low temperature. The auxiliary output 6b can provide for current operation at a significantly lower temperature, allowing a good performance of the electric motor and the electronic power unit and their construction from inexpensive standard components.

FIG. 10 illustrates another embodiment in which the thermostat 10 is disposed on the pipe 7 upstream of the pump 9, itself mounted immediately upstream of the engine 1. The bypass pipe 15 comprises a branch 17 passing through the electric motor 2, the control unit 3 and the electric pump 21. A temperature sensor 30 is mounted between the electric pump 21 and the control unit 3. Upstream of the electric pump 21, the branch 17 is connected to a three-way valve 23 also connected to the outlet 6b of the radiator 6 and to a pipe 31. The pipe 31 joins the branch 18 from the three-way valve 16. The branch 18 opens into a pipe 32 which passes through the heating radiator 4 which is connected at one end to the pipe 8 and at another end to a downstream portion of the thermostat 10. A temperature sensor 12 is associated with the thermostat 10. The thermostat 10 is suitable closing the pipe 7, while the pipe 32 is in free communication with the pump 9 and the motor 1.

The pump 21 and the valves 16 and 23 are controlled by the control unit which has not been shown in the figure. The three-way valve 16 connects the branch 17 to the branch 18 or the branch 19. The three-way valve 23 connects the branch 17 to the outlet 6b of the radiator 6 or the pipe 31.

Two set temperatures TC1 and TC2 are provided, compared in real time with the temperature measured by the sensor 30. The values of these thresholds are determined by the temperature tolerable by the control unit 3 of the electric motor 2. example TC1 = 60 ° C and TC2 = 70 ° C.

In thermal mode, the heat engine 1 is in operation and drives the pump 9. The valve 16 communicates the branches 17 and 18. The valve 23 communicates the branch 17 and the pipe 31.

In electrical mode, the mechanical pump 9 is at a standstill. The electric pump 21 is in operation. If the temperature measured by the sensor 30 is lower than TC1, for example in the case of a cold start, the valve 16 communicates the branches 17 and 19 and the valve 23 communicates the branch 17 and the pipe 31 It is thus possible to supply heat to the heating radiator 4 and / or to preheat the heat engine 1 in order to reduce its pollutant emissions during a subsequent start-up. The rise in temperature of the water is effective because the circuit water does not pass into the radiator 6.

If the temperature measured by the sensor 30 is between TC1 and TC2, it is expected to cool the electric traction members and heat the thermal traction members. The valve 16 then communicates the branches 17 and 18 and the valve 23 communicates the output 6b of the radiator 6 and the branch 17. It thus always ensures a flow in the heating radiator 4 and in the heat engine 1, while by cooling the electrical components by passing through the radiator 6.

If the temperature measured by the sensor 30 is greater than TC2, the valve 16 communicates the branch 17 and the branch 19 and the valve 23 communicates the output 6b of the radiator 6 and the branch 17. It thus benefits from the cooling provided by the entire radiator dimensioned for the dissipation of heat of the traction assembly constituted by the heat engine 1 and the electric motor 2.

In hybrid mode, both engines 1 and 2 are running.

If the temperature measured by the sensor 30 is lower than TC1 and that measured by the sensor 12 is lower than the opening temperature of the thermostat 10, the control unit 3 and the electric motor 2 are cooled without operating the pump 21. The valve 16 communicates the branches 17 and 19 and the valve 23 communicates the branch 17 and the pipe 31. This reduces the operating time of the electric pump. During a cold start, in hybrid mode, we take advantage of the heat dissipation of the electrical components to ensure a rapid rise in the temperature of the engine 1. This reduces these pollutant emissions at startup.

If the temperature measured by the sensor 30 is between TC1 and TC2, and the temperature measured by the sensor 12 is lower than the opening temperature of the thermostat, the valve 16 puts in communication the branches 17 and 18 and the valve 23 sets communicating the output 6b of the radiator 6 and the branch 17. The electric pump 21 is at a standstill. This ensures a good cooling of the electronic power components of the unit 3 by circulation of the coolant throughout the radiator 6.

If the temperature measured by the sensor 30 is greater than TC2 and the temperature measured by the sensor 12 is lower than the opening temperature of the thermostat, the electric pump 21 is started. The thermostat 10 being closed, we take advantage of the entire radiator 6 to cool the bodies of electric traction. The valve 23 communicates the output 6b of the radiator 6 and the branch 17. The valve 16 communicates the branch 17 and the branch 19. Thus, the two circuits are decoupled. The temperature of the cooling circuit of the electric traction units can be much lower than that of the heat engine circuit.

Alternatively, it can also be provided that the valve 16 communicates the branches 17 and 18. This provides a flow of water in the larger heat engine, which can promote the reduction of pollution by a rise in temperature more fast engine.

If the temperature measured by the sensor 12 is greater than the opening temperature of the thermostat, the electric pump 21 operates to provide a flow in the branch 17. The valve 16 communicates the branches 17 and 18. The valve 23 sets communicating the output 6b of the radiator 6 and the branch 17.

In Figure 11, is shown a variant similar to Figure 10, except that the electric motor 2 and its control unit 3 are connected in parallel, which reduces the pressure losses. The control of the valves is identical to that of FIG.

In Figure 12, there is illustrated an embodiment simplified to that of Figure 10, wherein the valve 23 and the pipe 31 are deleted. The outlet 6b of the radiator 6 is directly connected to the electric pump 21. It should be noted that the valve 23 serves in the previous embodiments, in electrical and hybrid mode, to promote a good temperature rise of the heat engine 1 and to a possible heating of the passenger compartment. If these two functions are not a priority, the embodiment of FIG. 12 can be used.

The embodiment illustrated in FIG. 13 is further simplified with respect to that illustrated in FIG. 12. The branch 19 is simplified and the three-way valve 16 is replaced by a simple valve 33 which makes it possible to close and thus to cut the communication between the branches 17 and 18. The valve 33 disconnects the branch of the electrical components in pure thermal mode. The preheating of the engine 1 and the heating of the passenger compartment are less efficient. However, if these two functions are not a priority, this embodiment is very economical because of the simplification of the cooling circuit and the simplification of the control. Only the valve 33 and the electric pump 21 must be controlled. The electric pump 21 can always be turned off when operating in hybrid mode, the thermostat 10 being closed and the temperature measured by the sensor 30 being less than TC2.

When the mechanical pump 9 is in operation and the valve 33 in the closed position, the branch 17 does not see circulation of coolant. The cooling of the heat engine 1 is carried out without disturbances due to the electric traction members.

When the valve 33 is in the open position, in electrical mode, it allows the circulation of cooling fluid and the cooling of the electric motor 2 and its control unit 3.

In hybrid mode, when the temperature measured by the sensor 30 is lower than TC2 and the temperature measured by the sensor 12 is lower than the opening temperature of the thermostat, the electric pump 21 and the flow of coolant in the branch are stopped. 17 is provided by the mechanical pump 9 driven by the heat engine 1.

If the temperature measured by the sensor 30 is greater than TC2 or if the temperature measured by the sensor 12 is greater than the opening temperature of the thermostat, the electric pump 21 is turned on.

The embodiment illustrated in FIG. 14 is close to that illustrated in FIG. 10, except that the electric motor 2 is no longer disposed on the branch 17 but on a pipe 34 mounted parallel to the heating radiator 4. cooling of the electric motor 2 can be ensured, either by passage of the coolant between the lines 8 and 34, or by the engine oil 1. In the latter case, there will be provided an oil-water temperature exchanger.

The embodiment illustrated in FIG. 15 is close to that illustrated in FIG. 1, except that branch 19 is omitted. The branch 20 is connected, on the one hand, to the valve 16 and, on the other hand, to the pipe 32 between the heating radiator 4 and the heat engine 1, the temperature sensor 12 being also mounted on this part of the pipe 32.

In thermal mode, the pump 9 is running, the valve 16 connects the branches 17 and 18. The valve 23 connects the branch 17 and the branch 22. The two circuits are then decoupled.

In electrical mode, the mechanical pump 9 is at a standstill, while the electric pump 21 is in operation.

If the temperature measured by the sensor 30 is lower than TC1, the valve 16 communicates the branches 17 and 20 and the valve 23 communicates the branches 17 and 22. It is thus possible to heat the heating radiator 4 while ensuring a temperature rise of the heat engine 1. The rise in temperature is effective because the coolant does not pass into the radiator 6.

If the temperature measured by the sensor 30 is between TC1 and TC2, the valve 16 communicates the branches 17 and 20 and the valve 23 communicates the outlet 6b of the radiator 6 and the branch 17. It always ensures a flow of cooling liquid in the heating radiator 4 and in the engine 1, while cooling the electrical components by passing through the radiator 6. If the thermostat 10 opens, then we have the entire radiator 6.

If the temperature measured by the motor 30 is greater than TC2, the valve 16 communicates the branches 17 and 18 and the valve 23 communicates the outlet 6b of the radiator 6 and the branch 17. The cooling of the electrical components is ensured by the third pass of the radiator 6, in other words by the part of the radiator 6 between the main output 6a and the auxiliary output 6b.

In hybrid mode, both engines 1 and 2 are running.

If the temperature measured by the sensor 30 is lower than TC1 and the temperature measured by the sensor 12 is lower than the opening temperature of the thermostat, the control unit 3 and the electric motor 2 can be cooled with the electric pump 21 stopped. The valve 16 communicates the branches 20 and 17 and the valve 23 communicates the branches 17 and 22. It reduces the operating time of the electric pump. During a cold start in hybrid mode, it takes advantage of the heat dissipation of the electrical components to ensure a rapid rise in the temperature of the engine 1 and possibly to ensure the heating of the passenger compartment.

If the temperature measured by the sensor 30 is between TC1 and TC2, and the temperature measured by the sensor 12 is lower than the opening temperature of the thermostat, the valve 16 puts in communication the branches 20 and 17 and the valve 23 sets communicating the output 6b of the radiator 6 and the branch 17. The electric pump 21 can remain at a standstill.

If the temperature measured by the sensor 30 is greater than TC2, or if the temperature measured by the sensor 12 is greater than the opening temperature of the thermostat, the electric pump 21 is in operation. The valve 16 communicates the branches 17 and 18 and the valve 23 communicates the output 6b of the radiator 6 and the branch 17. If the thermostat 10 is closed, the two circuits are completely decoupled. If the thermostat 10 is open, the two circuits are pooled at the output of the radiator 6, on the engine side.

The embodiment illustrated in Figure 16 is a simplification of that of Figure 15. The valve 23 is removed. The electric motor 2, its control unit 3, the temperature sensor 30 and the electric pump 21 are connected in series on the branch 18. The branch 17 directly connects the outlet 6b of the radiator 6 and the valve 16.

In thermal mode, the valve 16 communicates the branches 17 and 18.

In electrical mode, when the temperature measured by the sensor 30 is lower than the set temperature TC2, the valve 16 puts in communication the branches 20 and 17. The heat dissipation of the electrical components is therefore used to heat the heat engine 1 and the heating radiator 4. As soon as the temperature measured by the sensor 11 becomes greater than the temperature TC2, the valve 16 puts the branches into communication 17 and 18, which allows cooling of the electrical components with a good flow in the third pass of the radiator 6.

In hybrid mode, when the temperature measured by the sensor 30 is lower than TC2, the valve 16 communicates the branches 20 and 18. It is thus possible to stop the electric pump 21 and use the heat released by the electrical organs to heat the interior and ensure the temperature rise of the engine 1. As soon as the temperature measured by the sensor 30 is greater than the temperature TC2, the electric pump 21 is turned on and the valve 16 communicates the branches 17 and 18.

In Figure 17, is shown schematically a valve 16. The valve 23 may be of the same type. The valve 16 has a cylindrical body 35 inside which is mounted a movable member 36 comprising a central core 37 and arms 38 and 39. The movable member 36 is rotated by an electric motor. The coolant circulates in the annular space between the central hub 37 and the body 35. As shown in FIG. 17, the valve 16 is in a position allowing the circulation of fluid between the branches 18 and 19 and prohibiting the flow of fluid from the branch 17. The passage of the coolant is carried out as in a tube bent at 120 ° angle. The pressure drop is extremely low.

The embodiments in which the thermostat is placed upstream of the heat engine allow, in certain operating modes, to cut the power of the electric pump, in particular in hybrid mode, closed thermostat. The mechanical pump driven by the heat engine ensures a circulation of coolant in the radiator, then in the electric traction members, through the stopped electric pump. The coupling of the two cooling circuits, that of the heat engine and that of the electric motor, is achieved when the temperature in the components is low and the thermostat is closed. Coolant circulation is provided by one of the two pumps. In electric mode, the electric pump ensures a flow in all the branches of the circuit. In hybrid mode, the driven mechanical pump by the heat engine allows the circulation of coolant in all the organs of the circuit. As soon as the temperature in the electrical components reaches a certain value, the management of the cooling circuit, via the sensors and the control acting on the valves, allows the decoupling of the high temperature circuit of the heat engine and the circuit to be low temperature electric traction units.

The temperature of the coolant at the inlet of the electric traction members is very low in all cases of operation where said members dissipate heat in the cooling circuit. The electric pump operates less often, resulting in a reduction in energy consumption and the possibility of using conventional technology pumps, low cost and whose lifespan is greater than or equal to that of the vehicle. In all-electric mode, the heat dissipation by the electric traction members can be used for the temperature rise of the engine and also for the heating of the passenger compartment.

Claims (15)

1. Cooling system for hybrid propulsion vehicle comprising a heat engine (1) and at least one electric motor (2) of the type comprising a coolant able to cool the heat engine and electric motor, a radiator (6) capable of cooling the coolant by heat exchange with a current of air and comprising a plurality of cooling channels, an inlet and an outlet, a first pipe (7) between the outlet of the radiator and the heat engine and a second pipe (8) between the said heat engine and the inlet of the radiator, characterized in that the radiator (6) comprises an auxiliary outlet (6b) such that the coolant issuing from the auxiliary outlet is at a lower temperature than that of the main outlet (6a) linked to the first pipe, the said auxiliary outlet being linked to a bypass pipe (15) able to cool the electric motor.
2. System according to Claim 1, characterized in that the bypass pipe comprises a first branch (17) connected to the auxiliary outlet and a second branch (18) connected to a pipe upstream of the heat engine.
3. System according to Claim 1 or 2, characterized in that the first branch (17) is able to be connected to the first pipe (7).
4. System according to Claim 1, 2 or 3, characterized in that the bypass pipe comprises a third branch (19) connected to the second pipe.
5. System according to any one of Claims 1 to 4, characterized in that the bypass pipe comprises a fourth branch (20) connected to the outlet of the heat engine upstream of a thermostat (10).
6. System according to one of Claims 1 to 5, characterized in that the branches of the bypass pipe are connected together by a multiway valve (16).
7. System according to one of Claims 1 to 3, characterized in that it comprises a thermostat disposed on the first pipe (7), the thermostat being able to shut off the first pipe (7), a pipe linked to the electric motor (2) being to be in communication with the heat engine (1).
8. System according to Claim 7, characterized in that it comprises a first valve (16) able to place the outlet of the electric motor (2) in communication at least with the heat engine (1).
9. System according to Claim 7, characterized in that the first valve is of multiway type and is able to place the outlet of the electric motor (2) in communication with the heat engine (1) or with the second pipe (8).
10. System according to Claim 7, 8 or 9, characterized in that it comprises a second valve (23) able to place the auxiliary outlet (6b) in communication at least with the electric motor (2).
11. System according to Claim 10, characterized in that the second valve is of multiway type and is able to place the auxiliary outlet (6b) in communication with the electric motor (2) or with the heat engine (1).
12. System according to one of Claims 1 to 11, characterized in that the electric motor (2) is mounted on a bypass pipe parallel to the heat engine (1).
13. System according to any one of Claims 1 to 12, characterized in that the said auxiliary outlet is linked to a bypass pipe able to cool an electronic control unit (3).
14. Vehicle comprising a system according to any one of Claims 1 to 13.
15. Cooling method for hybrid propulsion vehicle comprising a heat engine and at least one electric motor that are cooled by the circulation of a coolant in the said engine and the said motor, a means of heat exchange capable of cooling the coolant by heat exchange with another fluid and provided with an inlet and with an outlet, in which the coolant stream divides in the means of heat exchange between a main outlet and an auxiliary outlet so that the coolant issuing from the auxiliary outlet exhibits a lower temperature than that of the main outlet, the said auxiliary outlet being linked to a bypass pipe able to cool the electric motor.

Images