Powertrain including an electric pump to heat a gearbox.

Abstract

A powertrain comprising an electric pump for heating a gearbox. The invention relates to a powertrain (2) comprising a heat-producing component (3), a first circuit (10) comprising a coolant, an electric pump (11) arranged in the first circuit (10) and intended to circulate the coolant for cooling the component (3), at least one part of the component (3) through which the coolant is able to circulate, an element (4) operating with oil, a second circuit (20) comprising the oil, the powertrain (2) comprising hardware and / or software means (5) for managing the operation of the electric pump (11) taking into account the coolant flow requirement of each of the parts according to the measured temperature of the coolant, in order to ensure heating of the element (4). Abstract figure: Figure 2

Description

Title of the invention: Powertrain comprising an electric pump for heating a gearbox. Technical field of the invention

[0001] The invention relates to a powertrain comprising an electric pump for circulating a coolant for a heat-producing component. The invention further relates to a vehicle comprising such a powertrain. The invention also relates to a method for controlling the electric pump of such a powertrain. Prior art

[0002] A vehicle, in particular a motor vehicle, comprises a powertrain. Such a powertrain generally comprises at least one internal combustion engine and / or at least one electric motor and at least one gearbox. Such a gearbox is generally arranged between the engine(s) and at least one drive shaft for transmitting torque to at least one means in contact with the ground, such as a wheel. Such a gearbox generally comprises gears meshing with one another and uses oil for its lubrication. Such a lubricating oil comprises an operating temperature range within which its lubricating properties are optimal.

[0003] However, when starting a powertrain, particularly in cold weather, the transmission oil only reaches its optimal operating temperature range after a certain period of time. Furthermore, particularly in hot weather and / or at high powertrain speeds and / or high transmission speeds, the transmission oil exceeds its optimal operating temperature range.

[0004] More specifically, at temperatures below this range, the oil is viscous, resulting in reduced gearbox efficiency and increased vehicle energy and / or fuel consumption. Conversely, at temperatures above this range, the oil film between meshing gears is insufficiently thick, leading to premature gear wear. Over time, such wear causes abnormal noises from the gearbox, malfunctions, and even gear breakage, ultimately resulting in gearbox failure and rendering it unusable.

[0005] Such a situation is not acceptable. Presentation of the invention

[0006] The object of the invention is to provide a powertrain that overcomes the above drawbacks. Furthermore, the invention allows the gearbox to be heated so that the oil quickly reaches the optimal temperature range.

[0007] To achieve this objective, the invention relates to a powertrain, particularly for a vehicle, comprising: - a heat-producing component, in particular a heat engine or a primary electrical machine, - a first circuit comprising a coolant, - an electric pump arranged in the first circuit and intended to circulate the coolant for cooling the component, - at least one component through which the coolant is able to circulate, said component comprising at least one heat exchanger and / or an EGR valve, and / or a turbocharger and / or an intake flap and / or a thermostat and / or a second electrical machine and / or an expansion tank, - a component that operates using oil, such as a gearbox, - a means of measuring the temperature of the coolant, particularly at the component level, - a second circuit including the oil, - a means of measuring the temperature of the element or of the oil at the level of the element, the powertrain including hardware and / or software means for managing the operation of the electric pump, including its starting and / or stopping and / or its rotation speed, taking into account the coolant flow requirement of each component according to the measured temperature of the coolant, in order to ensure in particular heating of the element.

[0008] The powertrain may include an exchanger between the first circuit and the second circuit.

[0009] The first circuit may include a valve arranged at the exchanger so as to prevent or not the circulation of the coolant in the exchanger.

[0010] The invention also relates to a vehicle, in particular a motor vehicle, comprising at least one powertrain as defined above.

[0011] The invention further relates to a method of controlling an electric pump of a powertrain as defined above, the method comprising a step of activating the electric pump to heat the element.

[0012] The method may further include a step of activating the electric pump to cool the element.

[0013] The method may include: - a step of measuring the temperature of the element, in particular the oil, by the means of measurement, - a step comparing the temperature of the element, particularly the oil, against a target temperature range, and If the temperature is lower than or equal to a lower threshold value in the target temperature range, the electric pump activation step is implemented to heat the element. In the event of a temperature greater than or equal to a higher threshold value in the target temperature range, the electric pump activation step is implemented to cool the element.

[0014] The step of activating the electric pump to heat the element may include activation at a first flow rate of the electric pump, in particular a first flow rate between 150 l / h and 250 l / h, and the step of activating the electric pump to cool the element may include activation at a second flow rate of the electric pump, in particular a second flow rate between 1100 l / h and 1300 l / h, the second flow rate being greater than the first flow rate.

[0015] The electric pump can be kept activated or can be activated while the heat-producing component is deactivated.

[0016] During the component's temperature rise phase, the step of activating the electric pump to heat the element can be conditioned on reaching a predetermined threshold temperature, in particular a threshold temperature of the component's coolant greater than or equal to 40 degrees Celsius. Presentation of the figures

[0017] These objects, features and advantages of the present invention will be described in detail in the following description of an embodiment and a method of execution given by way of non-limiting reference in relation to the accompanying figures, among which: [Fig.1] Fig.1 is a schematic view of a vehicle according to one embodiment.

[0018] [Fig.2] Fig.2 is a schematic view of a powertrain according to a method of implementation.

[0019] [Fig.3] The [Fig.3] is a block diagram of an embodiment of a method for controlling an electric pump of the powertrain according to an embodiment.

[0020] [Fig.4] [Fig.4] is a schematic view of a cooling circuit of the group powertrain according to one embodiment.

[0021] Fig. 1 schematically illustrates a vehicle 1, in particular a motor vehicle, according to one embodiment.

[0022] The vehicle includes a powertrain 2.

[0023] The powertrain 2 includes a heat-producing component 3. For example, component 3 includes, or is, a first electric machine and / or a heat engine, for example, an internal combustion engine. A first electric machine is, for example, an electric motor or a starter-alternator. Alternatively, component 3 is a battery.

[0024] The powertrain 2 further includes an element 4 operating with oil. Element 4 is preferably a gearbox lubricated with oil.

[0025] As illustrated in [Fig. 2], the powertrain 2 further comprises a first circuit 10 containing a coolant. The powertrain 2 further comprises an electric pump 11 arranged in the first circuit 10. The electric pump 11 is intended to circulate the coolant for cooling component 3.

[0026] As illustrated in [Fig. 4], the powertrain 2 further comprises at least one component of part 3 through which the coolant may, if necessary, circulate. The component comprises, for example, at least one heat exchanger 6, 31, 32, 34, 38, and / or an EGR valve 35, and / or a turbocharger 36, and / or an intake flap 37, and / or a thermostat 8, and / or a second electric motor, and / or an expansion tank 39.

[0027] The powertrain 2 further includes a means for measuring the temperature of the coolant or of component 3, preferably arranged at the level of component 3.

[0028] The powertrain 2 further includes a second circuit 20 comprising the lubricating oil for element 4.

[0029] The powertrain 2 further includes a means 21 for measuring the temperature of the element 4 or of the oil at the level of the element 4. The measuring means 21 is for example a sensor or a probe intended to measure the temperature of the oil directly, preferably by being in contact with the oil, or of the element 4 by being in contact for example with the element 4.

[0030] Preferably, the second circuit 20 including the oil is arranged so that the circulation of the coolant in the first circuit 10 ensures a heating of the element 4 as will be explained later.

[0031] The powertrain 2 further includes hardware and / or software means 5 for managing the operation of the electric pump 11 in order to ensure heating of the element 4 in at least certain operating situations. This management preferably includes starting and / or stopping and / or controlling the speed of rotation of the electric pump 11 taking into account the coolant flow requirement of each of the components according to the measured temperature of the coolant, for example in order to ensure heating of element 4. The hardware and / or software means 5 are connected, by a wired or wireless link, to the electric pump 11 and to the measuring means 21 so as to allow the transmission of information.

[0032] Advantageously, the powertrain 2 includes the heat exchanger 6 between the first circuit 10 and the second circuit 20. Advantageously, the first circuit 10 includes a valve 12 arranged at the heat exchanger 6. Thus, by activating the valve 12 towards a closed position, the circulation of the coolant in the heat exchanger 6 is prevented. Conversely, by activating the valve 12 towards an open position, the circulation of the coolant in the heat exchanger 6 is allowed.

[0033] The hardware and / or software means 5 for managing the operation of the electric pump 11 preferably include a computer and / or an electronic control unit (ECU) 7. As a reminder, the electric pump 11 ensures the circulation of the coolant. Thus, the components and / or parts of the engine 3 equipped with a cooling circuit using coolant also receive the coolant discharged by the pump 11. For example, these components and / or parts receiving coolant, particularly those illustrated in [Fig. 4], include all or some of the following elements: - the internal combustion engine 3, - an exchanger 31 for exhaust gas recirculation EGR (for Exhaust Gas Recirculation in Anglo-Saxon terms), - the EGR valve 35, - the turbocharger 36 or a turbocharger guide bearing, - a heater 32, notably intended for heating the passenger compartment, - the intake flap 37 of the internal combustion engine 3, - the thermostat 8, - a separator, - the second electric machine, notably of the alternator-starter type known by the Anglo-Saxon abbreviation BSG, - a heat exchanger 38 for engine coolant / lubricating oil, - a radiator 34, specifically a high-temperature radiator, for coolant / air, - the expansion tank 39, - a 40mm coolant inlet housing, - the exchanger 6, coolant / gearbox lubricating oil, intended to heat or cool the oil for the gearbox 4.

[0034] For example, as illustrated in [Fig.4], the electric pump 11 is arranged upstream of component 3. Preferably, downstream of component 3, the thermostat 8 is arranged so as to allow the coolant to be directed either into a low temperature loop or into a high temperature loop, depending on the temperature detected by the thermostat 8.

[0035] More specifically, initially, the control unit 7 estimates the required coolant flow rate for each component, in particular each component 6, 31, 32, 34. Depending on the circuit configuration, specifically the position of the thermostat 8 towards the low-temperature loop or the high-temperature loop, the control unit 7 converts the coolant flow rate (of the heat transfer fluid type) for each component into the coolant flow rate to be supplied to the cooling circuit by the electric pump 11. The control unit 7 then deduces, or calculates, the minimum flow rate required to supply all components. From this determined minimum flow rate, the control unit calculates the rotational speed of the electric pump 11 to achieve this flow rate. Finally, this rotational speed is sent as a setpoint to the electric pump 11.

[0036] As illustrated in [Fig.3], a method for controlling the electric pump 11 will now be described according to one embodiment.

[0037] Initially, the powertrain 2 is started. In other words, in step E5, the heat-producing component 3 is activated. As a reminder, preferably, component 3 is a heat engine.

[0038] We proceed to a step E10 of measuring a temperature T. This temperature T is the temperature measured by the measuring means 21 of the oil in the second circuit 20, or of the oil at the level of the element 4, or of the element 4 directly. As a reminder, the element 4 is, for example, a gearbox.

[0039] We proceed to a step E20 comparing the measured temperature T with a target range of optimal operating temperature for element 4. Note that the target range is predefined. The target range includes a lower threshold value Vinf and an upper threshold value Vsup.

[0040] Following the comparison in step E20, if the measured temperature T is less than or equal to the lower threshold value Vinf, the process proceeds to step E30. In this step E30, the electric pump 11 is activated to heat the element 4. Preferably, the activation of step E30 of the electric pump occurs at an initial flow rate. For example, the initial flow rate is between 150 l / h and 250 l / h at the component 3.

[0041] Following the comparison in step E20, if the measured temperature T is greater than or equal to the upper threshold value Vsup, the process proceeds to step E40. In this step E40, the electric pump 11 is activated to cool element 4. Preferably, The activation of step E40 of the electric pump occurs at a second flow rate. For example, the second flow rate is between 1100 l / h and 1300 l / h at component 3.

[0042] Following the comparison of step E20, in the event of a measured temperature T between the lower threshold value Vinf and the upper threshold value Vsup, we proceed to a step E45 in which we maintain or stop the circulation of the coolant in a branch of the circuit allowing us to manage the temperature of element 4.

[0043] Following step E30 or E40 or E45, we move on to a timing step E50.

[0044] At the end of the predefined delay time, the loop returns to measurement step E10 of the temperature T.

[0045] Alternatively, step E30 can be conditional upon reaching a predetermined temperature value of component 3 and / or the component 3 coolant (heat-up phase of the internal combustion engine). For example, below 40 degrees Celsius, the electric pump is deactivated, so that the flow of coolant in the circuit is zero regardless of the cooling requirements of the components. Such a delay in the activation of the electric water pump allows for an accelerated temperature rise in the combustion chamber, in order to limit particulate emissions, thus giving priority to the treatment of pollutants by the engine itself.

[0046] Alternatively, during the elapsed predefined waiting time of the timing step E50, the component or motor 3 is stopped or deactivated. In other words, the process proceeds to step E60, which stops component 3.

[0047] For example, step E60 of stopping component 3 leads immediately, or substantially immediately, to step E70 of deactivation or stopping the electric pump 11.

[0048] Alternatively, following step E60 of deactivating component 3, the operation of the electric pump 11 is maintained for a predetermined duration, for example (alternative not illustrated). In other words, a time delay is provided before step E70 of deactivating the electric pump 11.

[0049] Alternatively, following step E60 of deactivation of component 3, the electric pump is activated, in particular at the second flow rate so as to continue the cooling of element 4 (alternative not illustrated).

[0050] In summary, the solution allows a strategy for controlling the thermo-management of element 4, preferably of the transmission and / or gearbox type, so as to maintain the oil in the target temperature range giving it a high lubricating power.

[0051] More specifically, the heat from the motor or component 3 contributes to the rise in The transmission temperature during engine start-up, and even during vehicle start-up, is affected. The heat dissipated by the engine is thus rapidly transferred, in part, from the coolant (heat transfer fluid) of the first circuit 10 to the oil of the second circuit 20 via the heat exchanger 6, which is typically a coolant / oil type. Thanks to this solution, during start-up, the transmission oil temperature is warmed, increasing by approximately 25 degrees Celsius. This helps it reach the target operating temperature range more quickly. This increase allows the temperature to rise, for example, from 47 degrees (without heat exchanger 6) to 72 degrees (with heat exchanger 6) after 30 minutes of driving. Preferably, the target range is between 60 and 100 degrees.

[0052] When component or motor 3 is under load, particularly under heavy load, the transmission oil 4, and consequently the transmission structure, becomes hot. This heat from the oil and / or the transmission is partially transferred from the oil in the second circuit 20 to the coolant in the first circuit 10 via the heat exchanger 6. The heat is then dissipated, in particular, by the high-temperature radiator 34 located in the first circuit 10. This improves the reliability of the transmission by reducing the transmission and / or oil temperature. For example, at maximum vehicle speed, the solution allows the transmission oil temperature to be lowered by approximately 20 degrees. This reduction, for example, allows the temperature to decrease from 130 degrees to 110 degrees, i.e., to within a few degrees of the optimal operating range of the transmission.

[0053] Thanks to this solution, the oil contained in the gearbox and the gearbox structure remain predominantly at temperatures within the optimal target temperature range during the operation of the gearbox 3. The gearbox efficiency is thus improved, particularly by maintaining operation for longer periods within the range between 60 and 90 degrees Celsius, for example. In other words, the disadvantage of viscous oil at low temperatures, which causes a loss of gearbox efficiency, is avoided by heating the gearbox oil in step E30. Indeed, heating to quickly reach the lower threshold temperature Vinf prevents prolonged operation with viscous oil, which generates excessive friction, particularly on the gear teeth.As a result, excessive consumption of electricity and / or fuel by the vehicle is avoided during the start-up of component 3.

[0054] At high engine speeds and / or in high ambient temperature conditions, the oil temperature is limited, for example, to around 100 degrees. In particular, The oil films between the teeth of the meshing gears in the gearbox are then sufficiently thick to optimally lubricate the teeth. This prevents premature wear of the gear teeth, limits gearbox noise, and avoids malfunctions and the resulting long-term deterioration of the gearbox. Thus, the durability of the gear teeth is not affected over time. In summary, gearbox reliability is maximized by cooling (step E40) the gearbox oil so that it does not exceed, or only slightly exceeds, the upper temperature threshold value Vsup.

[0055] As mentioned previously, the solution makes it possible to use the "excess" heat from another vehicle component that would otherwise be dissipated externally, notably through the radiator 34. This "excess" heat is recovered to warm the transmission oil. Thanks to precise control of the electric pump 11, the oil is heated when cold to improve transmission efficiency and cooled when hot to prevent exceeding a critical temperature and thus limit transmission wear under these demanding operating conditions. As a reminder, the cooling circuit (first circuit 10) is equipped with the electric water pump 11, the control of which is managed by the computer 7 according to the different cooling requirements of each component. Once the cooling requirement of each component is defined, this is translated into the quantity or flow rate of the heat transfer fluid.Preferably, each requirement is established based on at least one parameter (for example, the gearbox oil temperature) whose value is compared to at least one table or map. For example, three maps are planned for engine 3, and / or three maps are planned for EGR cooler 31 and / or three maps are planned for cooler 6.

[0056] Each map is selected according to the measured engine coolant temperature and compared to a temperature range. For example, a first temperature range is below a value T1, a second temperature range is between the value T1 and a value T2, and a third temperature range is above a value T3, knowing that T1 < T2 < T3, so that each map corresponds to a temperature range.

[0057] In order to ensure the reliable operation of each of the components to be thermally regulated by the start-up of the electric pump, the controlled operation of the latter takes into account all the cooling requirements defined component by component according to at least one predetermined map of coolant flow requirements. Preferably, each component is associated with several maps, the choice of one of the maps being established according to the coolant temperature of the engine and / or the engine 3.

[0058] As a reminder, the gearbox and / or the gearbox oil is thermally controlled by being heated during the temperature rise phase up to its nominal operating point, in particular up to the lower threshold value Vinf, and by being cooled in case of exceeding the upper threshold value Vsup.

[0059] To this end, the transfer of heat from the coolant to the gearbox heat exchanger 6 is carried out according to a first cooling requirement, which is translated into a flow rate value and therefore a rotational speed of the electric pump to ensure the E30 heating phase or stage of the gearbox, for example with a first flow rate setpoint of approximately 200 L / h. The transfer of heat from the heat exchanger 6 to the high-temperature radiator 34 is carried out according to a second cooling requirement, which is translated into a flow rate value and therefore a rotational speed of the electric pump to ensure the E40 cooling phase or stage of the gearbox, for example with a second flow rate setpoint of approximately 1400 L / h.

[0060] Preferably, the second flow rate is greater than the first flow rate.

[0061] In other words, the computer 7 controls the electric pump 11 by receiving simultaneously the total cooling requirements of each of the components, based on the highest requirement or the total of the requirements.

[0062] In addition, other components can be associated with the gearbox, for example an electric machine contained in the gearbox casing.

[0063] Thus, in addition to the increased gearbox efficiency through heating, mechanical strength is enhanced, particularly endurance reliability, through oil cooling. The invention therefore makes it possible to combine improved energy efficiency and enhanced reliability with the same powertrain architecture.

[0064] The solution is simple and inexpensive. Indeed, it requires neither an additional valve nor an additional sensor, which makes it reliable and maintenance-free.

[0065] It should be noted that preferably, each conduit supplying coolant to each component and / or each internal circuit of each component includes a suitable nozzle to obtain the required flow rate for each component. As a reminder, the electric pump is preferably activated taking into account the cooling requirements of all components, even if this means circulating coolant through components that do not require cooling.

[0066] In addition, the water / oil type heat exchanger 6 can be of high capacity, for example capable of exchanging around 2000W for 25 degrees of temperature difference between the fluids.

[0067] In addition, the flow rate of the oil pump can be modified so as to go from a flow capacity of around 11 / min to a flow rate of around 4 1 / min for example, in particular by using a specific pump.

[0068] In addition, the piloting of the oil pump for the gearbox oil can be adapted to the solution.

[0069] As a note, the solution according to the invention therefore achieves the desired objective of making a gearbox more reliable and offers the following advantages: - it is economical, - It can be used on all ranges of vehicles with a gearbox that has a cooling system, including automatic gearboxes and / or those intended for hybrid or plug-in hybrid vehicles, or even electric vehicles. - it can be adapted to other vehicles, such as heavy goods vehicles, or even other means of transport such as trains.

Claims

Demands

1. Powertrain (2), in particular for a vehicle (1), comprising: - a heat-producing component (3), in particular a heat engine or a first electric machine, - a first circuit (10) comprising a coolant, - an electric pump (11) arranged in the first circuit (10) and intended to circulate the coolant for cooling the component (3), - at least one part of the component (3) through which the coolant is capable of circulating, said part comprising at least one heat exchanger (6, 31, 32, 34, 38) and / or an EGR valve (35), and / or a turbocharger (36) and / or an intake flap (37) and / or a thermostat (8) and / or a second electric machine and / or an expansion tank (39), - an oil-operating element (4), in particular a gearbox, - a means (13) for measuring the temperature of the coolant, in particular at the component level (3),- a second circuit (20) comprising the oil, - a means for measuring the temperature of the element (4) or of the oil at the level of the element (4), characterized in that the powertrain (2) comprises hardware and / or software means (5) for managing the operation of the electric pump (11), in particular its starting and / or stopping and / or its rotation speed, taking into account the coolant flow requirement of each of the components according to the measured temperature of the coolant, in order to ensure heating of the element (4).

2. Powertrain (2) according to the preceding claim, characterized in that it comprises an exchanger (6) between the first circuit (10) and the second circuit (20).

3. Powertrain (2) according to the preceding claim, characterized in that the first circuit (10) includes a valve (12) arranged at the exchanger (6) so as to prevent or not the circulation of the coolant in the exchanger (6).

4. Vehicle (1), in particular a motor vehicle, characterized in that it comprises at least one powertrain (2) according to one of the re- demands 1 to 3.

5. Method of piloting an electric pump (11) of a powertrain (2) according to any one of claims 1 to 3, characterized in that it comprises a step (E30) of activating the electric pump (11) to heat the element (4).

6. Method according to the preceding claim, characterized in that it further comprises a step (E40) of activating the electric pump (11) to cool the element (4).

7. A method according to the preceding claim, characterized in that it comprises: - a measurement step (E10) of the temperature (T) of the element (4), in particular of the oil, by the measuring means (21), - a comparison step (E20) of the temperature (T) of the element (4), in particular of the oil, with respect to a target temperature range, and in the event of temperature (T) less than or equal to a lower threshold value (Vinf) of the target temperature range, the step (E30) of activating the electric pump (11) to heat the element (4) is implemented, in the event of temperature (T) greater than or equal to an upper threshold value (Vsup) of the target temperature range, the step (E40) of activating the electric pump (11) to cool the element (4) is implemented.

8. A method according to any one of claims 6 or 7, characterized in that the step (E30) of activating the electric pump (11) to heat the element (4) includes an activation at a first flow rate of the electric pump (11), in particular a first flow rate between 150 l / h and 250 l / h, and in that the step (E40) of activating the electric pump (11) to cool the element (4) includes an activation at a second flow rate of the electric pump (11), in particular a second flow rate between 1100 l / h and 1300 l / h, the second flow rate being greater than the first flow rate.

9. A method according to any one of claims 5 to 8, characterized in that the electric pump (11) is kept activated or is activated while the heat-producing component (3) is deactivated.

10. A method according to any one of claims 5 to 9, characterized in that during the heating phase of the component (3), the step (E30) of activating the electric pump (11) to heat the element (4) is conditioned on reaching a predetermined threshold temperature, in particular a threshold temperature of the coolant of component (3) greater than or equal to 40 degrees Celsius.

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