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EP-3978285-B1 - METHOD FOR MANAGING A CHARGE LEVEL OF AN ELECTRICAL ENERGY STORAGE ELEMENT FOR A POWER TRAIN, POWERTRAIN AND VEHICLE

EP3978285B1EP 3978285 B1EP3978285 B1EP 3978285B1EP-3978285-B1

Inventors

  • CHRISTOU, PANAGIOTIS
  • MILLON, JEAN-PIERRE
  • POMMERY, William

Dates

Publication Date
20260513
Application Date
20210921

Claims (10)

  1. Management method (10) of a charge level (12) of an electric energy storage element (3) of a powertrain (1) of a hybrid motor vehicle, said powertrain (1) comprising at least one electric motor (2) driving the vehicle alone, at least one generator set (4) comprising a heat engine (5) driving an electric generator (6), the heat engine being able to operate at at least two compression ratios, the electric energy storage element (3) storing the electrical energy produced by the generator (6) and supplying the electric motor (2), the management method (10) controlling the heat engine (5) at a first compression ratio (15) or at a second compression ratio (16) depending on the level of charge (12) of the electrical energy storage element (3) and optionally on an electrical consumption (11) of the electric motor (2), characterised in that the heat engine (5) is maintained at the first compression ratio (15) when the level of charging (12) of the electrical energy storage element (3) is greater than a low state of charge threshold (13) and less than a high state of charge threshold (14), the high state of charge threshold (14) being greater than the low state of charge threshold (13), and the heat engine (5) is switched to the second compression ratio (16) which is the higher of the two compression ratios, when the level of charge (12) of the electrical energy storage element (3) is less than the low state of charge threshold (13).
  2. Management method (10) according to claim 1, wherein the heat engine (5) is maintained at the second compression ratio (16) after the charge level (12) of the electric energy storage element becomes lower than the low state of charge threshold (13) and as long as the charge level (12) of the electric energy storage element (3) is lower than the high state of charge threshold (14), and the operation of the heat engine (5) is interrupted when the charge level (12) of the electric energy storage element (3) is higher than the high state of charge threshold (14).
  3. Management method (10) according to claim 1 or 2, wherein the heat engine (5) is kept off as long as the charge level (12) of the electric energy storage element (3) is higher than the high state of charge threshold (14), and the heat engine (5) is turned on when the charge level (12) of the electric energy storage element (3) is lower than the high state of charge threshold (14).
  4. Management method (10) according to any one of claims 1 to 3, wherein the low state of charge threshold (13) is between 5% and 60% of a maximum charge level of the electric energy storage element (3).
  5. Management method (10) according to any one of claims 1 to 4, wherein the high state of charge threshold (14) is between 40% and 100% of a maximum charge level of the electric energy storage element (3).
  6. Management method (10) according to any one of claims 1-5, controlling the heat engine (5) at the first compression ratio (15) or the second compression ratio (16) according to the power consumption of the electric motor (2), as long as the charge level (12) of the electric energy storage element (3) is lower than the high state of charge threshold (14) and higher than the low state of charge threshold (13).
  7. Powertrain (1) for a hybrid motor vehicle, comprising at least one electric motor (2) driving the vehicle alone, at least one generator set (4) comprising a heat engine (5) driving an electric generator (6), the heat engine being able to operate at at least two compression ratios, an electric energy storage element (3) storing the electric energy produced by the generator (6) and powering the electric motor (2), characterised in that the powertrain further comprises a control module (8) configured to implement a method for managing (10) a charge level (12) of 1 electric energy storage element (3) according to any one of the preceding claims.
  8. Powertrain (1) according to the preceding claim, wherein the heat engine (5) comprises a movable assembly (20) provided with at least one crankshaft (21), at least one piston (22) and at least one connecting rod (23) connecting the piston (22) to the crankshaft (21), said connecting rod (23) comprising a means (30) for adjusting a height of the piston (22) to operate the heat engine (5) at the first compression ratio (15) or at the second compression ratio (16).
  9. Powertrain (1) according to the preceding claim, wherein the means (30) for adjusting the height of the piston (22) comprises at least one eccentric (31) which carries an axis of the piston (22) and whose position is controlled by two control members (32) carried by the connecting rod (23).
  10. Motor vehicle comprising a powertrain (1) according to any one of claims 7 to 9.

Description

The present invention relates to the field of hybrid powertrains and more particularly concerns a method of managing the charge level of an electrical energy storage element within such a powertrain. Hybrid technology consists of a combination of a combustion engine and an electric motor, each contributing to the operation of the vehicle, thus resulting in lower fuel consumption, particularly for the purpose of environmental preservation. Among the various hybrid technologies available in the automotive industry, some involve vehicle propulsion entirely powered by the electric motor. The internal combustion engine's primary function is to recharge an electrical energy storage unit, which in turn supplies power to the electric motor. These technologies are commonly referred to as "series hybrid" technologies. A specific application of these "series hybrid" technologies is the range extender. When the vehicle's electric range is depleted (i.e., the battery is empty), the internal combustion engine starts to recharge the battery, thus extending the vehicle's range, for example, to an electric charging station. One drawback of this type of powertrain is that the internal combustion engine operates at a single operating point. When the internal combustion engine has only one operating point, the energy it produces and which is transferred to the electrical energy storage unit remains constant over time. Consequently, depending on the vehicle's electrical consumption, the energy supplied by the internal combustion engine to the electrical energy storage unit may be insufficient or, conversely, excessive. Insufficient energy input leads to a discharge of the electrical energy storage element in the medium or long term, and therefore tends to reduce the vehicle's range. Conversely, if the internal combustion engine operates at a single operating point resulting in high and constant activity, then the internal combustion engine tends to wear out more quickly. For example, the document WO2020170634 describes a process that presents this type of drawback. FROM 10 2010 024896 A1 This system features a modular hybrid drive, particularly for passenger cars. The drive incorporates an electrodynamic drive unit that can optionally function as an electric generator. A thermodynamic drive unit comprises a four-stroke combustion engine, where the thermodynamic drive unit's throttle is controlled interactively via rotary servo valves. The two drive units and a coupling unit are formed as separate modules combined in a series arrangement and mechanically connected to the two axial ends of a working shaft using a standardized connection technique, such that the power from each module in the series arrangement is transferred to the working shaft. EP 3418532 A1 This invention presents a device for adjusting the compression ratio of an internal combustion engine. This adjustment device comprises: a connecting rod including a small end, a big end for receiving a crankshaft of the engine, and a connecting rod body connecting the small end to the big end; a piston including a piston shaft; an eccentric comprising a main shaft installed at the small end of the connecting rod and having an eccentric bore for receiving the piston shaft; a lever cooperating with the main shaft so as to rotate the main shaft by pivoting the lever; and at least one actuating element being connected on one side to the connecting rod body and on the other side to the lever so as to pivot the lever. According to the invention, the connecting rod and the actuating element are respectively made of materials having different coefficients of thermal expansion. The present invention aims to overcome such a drawback by proposing a method for managing the charge level of an electrical energy storage element in a group powertrain of a hybrid motor vehicle, said powertrain comprising at least one electric motor driving the vehicle by itself, at least one generator set comprising a thermal engine driving an electric generator, the thermal engine being capable of operating at at least two compression ratios, the electrical energy storage element storing the electrical energy produced by the generator, the management method controlling the thermal engine at a first compression ratio or a second compression ratio depending on the charge level of the electrical energy storage element and/or the electrical consumption of the electric motor, characterized in that the thermal engine is maintained at the first compression ratio when the charge level of the electrical energy storage element is above a low charge state threshold and below a high charge state threshold, the high charge state threshold being above the low charge state threshold, and the thermal engine is switched to the second compression ratio when the charge level of the electrical energy storage element is below the low charge state threshold. According to the invention, the second compression ratio is the high