FR3074525A1 - MOTORIZING GROUP COOLING CIRCUIT OPTIMIZING THE RISE IN TEMPERATURE OF A GEARBOX - Google Patents

Abstract

The invention relates mainly to a cooling circuit (10) comprising: - a heat-transfer fluid outlet housing (14) comprising first outlet (15) and inlet (16) ducts opening respectively into the heat engine ( 11) and in the housing (14) from the heat engine (11), - second outlet (19) and inlet (20) ducts opening respectively into a radiator (22) and into the housing (14). from the radiator (22), characterized in that said cooling circuit (10) further comprises a fluid supply circuit (37) mounted as a bypass of the second inlet duct (20) for supplying coolant l heat exchanger of the gearbox (12) and a turbocharger heat exchanger (40), and in that a return line (41) is able to ensure a return of the heat transfer fluid from the heat exchanger. heat of the gearbox (12) and the heat exchanger turbocharger (40) to the engine (11).

Description

© COOLING CIRCUIT OF MOTOR-DRIVEN GROUP OPTIMIZING THE TEMPERATURE RISE OF A GEARBOX.

FR 3,074,525 - A1 (57) The invention relates mainly to a cooling circuit (10) comprising:

a housing (14) for outputting a heat-transfer fluid comprising first outlet (15) and inlet (16) pipes opening respectively into the heat engine (11) and into the housing (14) coming from the heat engine ( 11) *

- second outlet (19) and inlet (20) pipes opening respectively into a radiator (22) and into the housing (14) coming from the radiator (22), characterized in that said cooling circuit (10) further includes a fluid supply circuit (37) mounted as a bypass of the second inlet line (20) for supplying heat transfer fluid to the gearbox heat exchanger (12) and a heat exchanger of turbocharger (40), and in that a return line (41) is capable of ensuring a return of the heat transfer fluid from the gearbox heat exchanger (12) and from the turbocharger heat exchanger (40) to the engine (11) ·

The powerplant cooling system optimizes the temperature rise of a gearbox The present invention relates to a powerplant cooling circuit optimizing the temperature rise of a gearbox. The invention finds a particularly advantageous, but not exclusive, application with automatic gearboxes.

A conventional coolant circuit includes a coolant outlet box known by the abbreviation BSE for Water Outlet Box, because the coolant is generally a water-based liquid comprising additives . This outlet box is provided with several inlets and several outlets, corresponding to respective loops of fluid circulation.

It is necessary to cool the lubricating oil of the gearbox when this oil is too hot, but it is also necessary to warm the lubricating oil when the vehicle is started when the oil is too cold and not viscous enough. to ensure good lubrication. This should not advantageously be achieved at the expense of heating the passenger compartment when starting the motor vehicle when the outside temperature is cold, heating the passenger compartment having priority.

It is known to provide cooling of the gearbox by bypassing the heat transfer fluid circuit at the outlet of the radiator. The first advantage of this solution is that we take advantage of the cold heat transfer fluid leaving the radiator to cool the gearbox. The second advantage is that such a configuration does not have a negative impact on the thermal performance of the passenger compartment during the rise in temperature since there is no circulation of heat transfer fluid in closed thermostat.

The drawbacks of this solution are that it is impossible to optimize the temperature rise of the gearbox during the temperature rise of the heat transfer fluid of the engine, because there is no flow in closed thermostat. In addition, if the thermostat is not very open, which is the case on lightly loaded cycles, the flow of heat transfer fluid in the gearbox is very low and there is therefore little heat exchange.

It has also been proposed an architecture of heat transfer fluid circuit with a permanent flow in the gearbox, including when the thermostat is closed. This solution has the advantage of having a permanent flow rate in the gearbox heat exchanger and high enough to promote heat exchange in the gearbox. The disadvantage of this solution is that it penalizes the rise in temperature of the heat transfer fluid of the engine which produces two consequences.

On the one hand, the friction of the engine increases although its are compensated by the gains on the friction of the gearbox. On the other hand, there follows a penalty on the thermal performance of the passenger compartment, insofar as the heat transfer fluid of the engine passing through the air heater is colder.

The invention aims to effectively remedy the aforementioned drawbacks by proposing a cooling circuit for powertrain provided with a heat engine and a gearbox associated with a heat exchanger, said cooling circuit comprising:

- an outlet box for a heat transfer fluid comprising first outlet and inlet pipes opening respectively into the heat engine and into the case coming from the heat engine,

- second outlet and inlet pipes opening respectively into a radiator and into the housing coming from the radiator,

- A thermostat capable of controlling an amount of heat transfer fluid circulating towards the radiator as a function of a temperature of the heat engine, characterized in that said cooling circuit further comprises a fluid supply circuit mounted as a bypass of the second pipe inlet for supplying heat transfer fluid to the gearbox heat exchanger and a turbocharger heat exchanger, and in that a return line is capable of ensuring a return of the heat transfer fluid coming from the heat exchanger heat from the gearbox and from the turbocharger heat exchanger to the engine.

The invention thus optimally promotes the rise in temperature of the gearbox by supplying the heat exchanger with a hot heat transfer fluid and then cooling it by supplying the heat exchanger. heat with a cold heat transfer fluid. The optimal temperature of the gearbox lubricating oil is thus quickly reached to operate it at its point of maximum efficiency, while being able to effectively cool the lubricating oil as soon as its temperature becomes too high.

In one embodiment, the fluid supply circuit is configured such that, when the thermostat is closed, the heat transfer fluid from the heat engine is able to pass through the heat exchanger of the gearbox and the turbocharger heat exchanger. Thus, during the rise in temperature of the heat engine, it takes advantage of the calories from it to reduce the friction losses of the gearbox.

In one embodiment, the fluid supply circuit is configured such that, when the thermostat is open, the heat transfer fluid from the second inlet pipe from the radiator is able to pass through the heat exchanger in the gearbox and in the turbocharger heat exchanger. Thus, when the heat engine is hot, the gearbox and the turbocharger can be cooled by taking advantage of the heat transfer fluid leaving the radiator which has the lowest temperature of the cooling circuit.

In one embodiment, the return pipe is connected to the second outlet pipe and a pump is able to circulate the heat transfer fluid inside the radiator when the thermostat is closed and / or when the engine is stopped .

According to one embodiment, a non-return valve is mounted between the pump and a tap of the return pipe on the second outlet pipe.

According to one embodiment, the return pipe is connected to the first outlet pipe via a nozzle.

In one embodiment, the return pipe is connected to the second inlet pipe from the radiator via a nozzle.

In one embodiment, a non-return valve is mounted upstream of the tap.

According to one embodiment, an additional component, such as a heat exchanger for an inverter of a rotary electric machine, is mounted in parallel with respect to the heat exchanger of the gearbox and the heat exchanger of turbocharger.

The invention also relates to a motor vehicle, characterized in that it comprises a cooling circuit as defined above.

The invention will be better understood on reading the following description and on examining the accompanying figures given by way of illustration but in no way limit the invention.

Figure 1 is a schematic representation of a powertrain cooling circuit according to the present invention;

Figures 2a to 2c are schematic representations illustrating the operation of the cooling circuit according to the invention according to different life phases of the engine;

Figure 3 is a schematic representation of the cooling circuit according to the invention illustrating an alternative layout of the fluid return pipe;

Figure 4 is a schematic representation of the cooling circuit according to the invention illustrating an alternative embodiment in which an additional heat exchanger is connected to the circuit derived from cooling fluid.

Identical, similar, or analogous elements retain the same reference from one figure to another.

Figure 1 shows a cooling circuit 10 of a powertrain comprising a heat engine 11 and a gearbox associated with a heat exchanger 12. This cooling circuit 10 is able to perform the thermal regulation of the gearbox heat exchanger 12 both for raising the temperature of the gearbox lubricating oil and for cooling it. The heat transfer fluid circulating in the circuit 10 is for example a water-based liquid containing additives, in particular anti-freeze products.

More specifically, the cooling circuit 10 comprises a housing 14 for the outlet of a heat transfer fluid comprising first outlet pipes 15 and inlet 16 for fluid opening respectively into the engine 11 and into the housing 14 from the engine 11 passing through at least one heat exchanger 17 of the heat transfer fluid with at least one element associated with the engine 11. There is also a direct passage between the engine and the housing 14 with a direct return of the heat transfer fluid from the engine 11 to the housing 14.

The cooling circuit 10 also includes second outlet pipes 19 and inlet 20 opening respectively into a radiator 22 and into the housing 14 from the radiator 22. Incidentally, the radiator 22 may have an annex outlet pipe of fluid 23 connecting said radiator 22 to the engine 11, via a degassing box 25. Conventionally, a main pump 26 circulates the cooling fluid in the engine 11. The pump 26 is disposed on the first fluid outlet pipe 15 opening into the motor 11 from the housing 14.

The cooling circuit 10 has a third outlet pipe 28 from the housing 14 to an air heater 30 disposed in the vehicle interior and a third inlet pipe 31 from the air heater 30 to the first pipe outlet 15 from the housing 14 to the heat engine 11.

The housing 14 comprises a first enclosure 33 and a second enclosure 34. The first enclosure 33 carries an outlet opening in the third outlet pipe 28 to the air heater 30 and an outlet opening in the second outlet pipe 19 to the radiator 22. For the aforementioned passage of fluid between the engine and the housing 14, the first enclosure 33 of the housing 14 has an inlet directly connected to the engine 11 for receiving fluid leaving the engine 11, this inlet being visible but not referenced on Figure 1. A thermostat 35 is able to control an amount of heat transfer fluid flowing to the radiator 22 according to a temperature of the engine

11. To this end, the thermostat 35 blocks or at least partially opens the output of the first enclosure 33 to the radiator 22 as a function of the temperature of the engine 11.

The second enclosure 34 has an outlet opening into the first outlet pipe 15 from the housing 14 to the heat engine 11 and two inputs, one of which receives the second inlet pipe 20 coming from the radiator 22 and the other receives a downstream end of the first fluid inlet pipe 16 opening into the housing 14 coming from the engine 11 passing through at least the heat exchanger 17 of the heat transfer fluid with at least one element associated with the engine.

An auxiliary pressure valve may if necessary be disposed between, on the one hand, the passage or passages between the two enclosures 33, 34 and, on the other hand, the inlet of the housing 14 for the circulation of fluid coming from the radiator 22 and the outlet from the housing 14 for the circulation of fluid in the direction of the inlet portion of the internal circuit to the engine 11 via the first outlet pipe from the housing 14 to the engine 11.

There is also provided a fluid supply circuit 37 mounted as a bypass of the second inlet line 20 for supplying heat transfer fluid to the heat exchanger of the gearbox 12 and a turbocharger heat exchanger 40 An output of the heat exchanger of the gearbox 12 and an output of the turbocharger heat exchanger 40 are connected to a return line 41 ensuring a return of the heat transfer fluid to the heat engine 11.

To this end, a bypass 42 connected to the second inlet pipe 20 is connected on the one hand to the turbocharger heat exchanger 40 via a pipe 43 and on the other hand in parallel to the heat exchanger. heat from the gearbox 12 via a line 44. The flow of fluid from the second inlet line 20 is thus separated between a first flow passing through the turbocharger heat exchanger 40 and a second flow passing through the heat exchanger gearbox heat 12. The outputs of the turbocharger heat exchanger 40 and the heat exchanger of the gearbox 12 are connected to the return line 41 respectively via lines 46 and 47.

The return pipe 41 is advantageously connected to the first outlet pipe 15 via a nozzle 48. A non-return valve 50 is mounted upstream of the return nozzle 48. In addition, the return pipe 41 is connected to the second outlet pipe 19.

A pump 51 is able to circulate the heat transfer fluid inside the radiator 22 when the thermostat 35 is closed and / or when the heat engine 11 is stopped, as described in more detail below. A non-return valve 52 is mounted between the pump 51 and a nozzle 53 with the second outlet pipe 19.

The following describes, with reference to FIGS. 2a, 2b, 2c, the operation of the cooling circuit 10 according to the present invention according to different life phases of the heat engine 11.

As illustrated in Figure 2a, when the thermostat 35 is closed, the heat transfer fluid from the engine 11 is able to circulate in the heat exchanger of the gearbox 12 and the turbocharger exchanger 40 The direction of circulation of the fluid is represented by the arrows F1. Thus, this makes it possible to heat the gearbox when starting the vehicle and thus reduce friction losses.

As illustrated in Figure 2b, when the thermostat 35 is open, the heat transfer fluid from the second inlet line 20 from the radiator 22 is adapted to pass through the exchanger of the gearbox 12 and l turbocharger exchanger 40. The direction of circulation of the fluid is represented by the arrows F2. Thus, when the heat engine 11 is hot, the gearbox and the turbocharger can be cooled by taking advantage of the heat transfer fluid leaving the radiator 22 which is at the lowest temperature of the circuit.

As illustrated in Figure 2c, when there is a need for cooling of the gearbox or the turbocharger while the engine 11 is stopped for example during a stop at red light or during the activation of an electric traction mode, activation of the pump 51 makes it possible to circulate heat transfer fluid in the heat exchangers 12, 40 of these two components while passing it through the radiator 22. The direction of circulation of the fluid is represented by the arrows F3. The pump 51 is also able to circulate the heat transfer fluid according to the arrows F3 inside the radiator 22 when the thermostat 35 is closed.

Alternatively, as illustrated in Figure 3, the return pipe 41 is connected, not on the first outlet pipe 15, but on the second inlet pipe 20 from the radiator 22 via a nozzle 54. A non-return valve 50 'is mounted upstream of the tap 54.

According to another alternative embodiment illustrated in Figure 4, an additional component 55 is mounted in parallel with respect to the exchanger of the gearbox 12 and the turbocharger exchanger 40. For this purpose, the component 55 is connected to the branch 42 via a line 58 connected in parallel with the lines 43 and 44. The output of the component 55 is connected to the return line 41. This component 55 is for example a heat exchanger of an inverter of an electric machine rotating.

Claims (10)

1. Cooling circuit (10) for a powertrain provided with a heat engine (11) and a gearbox associated with a heat exchanger (12), said cooling circuit (10) comprising: - a housing (14) for the outlet of a heat-transfer fluid comprising first outlet (15) and inlet (16) pipes opening respectively into the heat engine (11) and into the case (14) coming from the heat engine (11) - second outlet (19) and inlet (20) pipes opening respectively into a radiator (22) and into the housing (14) coming from the radiator (22), - a thermostat (35) capable of controlling an amount of heat transfer fluid circulating towards the radiator (22) as a function of a temperature of the heat engine (11), characterized in that said cooling circuit (10) further comprises a circuit supply of fluid (37) mounted as a bypass of the second inlet pipe (20) for supplying heat transfer fluid to the heat exchanger of the gearbox (12) and to a turbocharger heat exchanger (40), and in that a return line (41) is capable of ensuring a return of the heat transfer fluid coming from the heat exchanger of the gearbox (12) and from the turbocharger heat exchanger (40) towards the heat engine (11). 2. Cooling circuit according to claim 1, characterized in that the fluid supply circuit (37) is configured so that, when the thermostat (35) is closed, the heat transfer fluid from the heat engine (11) is adapted to pass through the gearbox heat exchanger (12) and the turbocharger heat exchanger (40). 3. Cooling circuit according to claim 1 or 2, characterized in that the fluid supply circuit (37) is configured in such a way that, when the thermostat (35) is open, the heat transfer fluid from the second line of inlet (20) from the radiator (22) is adapted to pass through the gearbox heat exchanger (12) and into the turbocharger heat exchanger (40). 4. Cooling circuit according to any one of claims 1 to 3, characterized in that the return line (41) is connected to the second outlet line (19) and in that a pump (51) is suitable circulating the heat transfer fluid inside the radiator (22) when the thermostat (35) is closed and / or when the heat engine (11) is stopped. 5. Cooling circuit according to claim 4, characterized in that a non-return valve (52) is mounted between the pump (51) and a nozzle (53) of the return pipe (41) on the second outlet pipe ( 19). 6. Cooling circuit according to any one of claims 1 to 5, characterized in that the return line (41) is connected to the first outlet line (15) via a nozzle (48). 7. Cooling circuit according to any one of claims 1 to 5, characterized in that the return pipe (41) is connected to the second inlet pipe (20) coming from the radiator (22) via a nozzle ( 54). 8. Cooling circuit according to claim 6 or 7, characterized in that a non-return valve (50, 50 ') is mounted upstream of the nozzle (48, 54). 9. Cooling circuit according to any one of claims 1 to 8, characterized in that an additional component (55), such as a heat exchanger for an inverter of a rotating electric machine, is mounted in parallel with respect to the gearbox heat exchanger (12) and the turbocharger heat exchanger (40). 10. Motor vehicle, characterized in that it comprises a cooling circuit as defined according to any one of the preceding claims.