Vehicle powertrain, control arrangement and method for controlling a vehicle powertrain

Abstract

A vehicle powertrain (2) includes an electric machine (3), a combustion engine (4), a planetary gear set (5), a first shaft (11) and a second shaft (12). The motor (3) is connected to the second shaft (12). The first shaft (11) is connected to a sun gear (20) of the planetary gear set (5) and the second shaft (12) is connectable to a ring gear (23) of the planetary gear set (5) via a ring gear coupling (34). Both the second shaft (12) and an output shaft (13) of the combustion engine (4) are connectable to the first shaft (11) via a coupling arrangement (30). The present disclosure also relates to: a vehicle (1) comprising the vehicle powertrain (2); a method for controlling the vehicle powertrain (2); a control arrangement (100) configured to control the vehicle powertrain (2); a computer program; and a computer readable medium.

Description

Technical Field

[0001] The present disclosure generally relates to a vehicle powertrain, and a vehicle including the vehicle powertrain. The present disclosure generally also relates to a method for controlling a vehicle powertrain. Moreover, the present disclosure generally relates to a computer program and a computer-readable medium. The present disclosure generally also relates to a control arrangement configured to control a vehicle powertrain. Background Art

[0002] Efforts to reduce emissions and improve fuel economy of heavy vehicles (e.g., trucks and buses) have led to the development of vehicles that include a vehicle powertrain that includes one or more electric machines that act as a propulsion unit and are configured to be powered by an energy storage device. Examples of such vehicles include battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs), such as plug-in hybrid electric vehicles (PHEVs).

[0003] One of the major obstacles when seeking to electrify heavy vehicles is the considerable weight and cost of the energy storage device required to propel the heavy vehicle until it can be stopped to recharge the energy storage device (i.e., battery). Today, vehicles suitable for operation in very transient cycles, such as vehicles suitable for urban transportation or regional distribution, can usually be converted into BEVs with acceptable increased weight and cost, which is caused by the size of the energy storage device required for the expected operation of the vehicle. This is mainly due to the fact that charging can often be carried out by regenerative braking before reaching the next charging station.

[0004] However, for example, long-distance transport trucks, it is neither cost-effective nor energy-efficient to run solely on stored electrical energy. Heavy vehicles consume most of their available energy at high and steady speeds, which is a situation that long-distance transport trucks may often experience in a considerable part of the driving cycle. With the energy density of today's batteries and assuming that the daily long-distance transport operation is about 500km, the weight added by the energy storage device with sufficient capacity to ensure one-day operation will be about 3500kg to 4000kg. This will not only sacrifice the possible cargo weight, but also create limitations in space and vehicle specifications due to the size of such energy storage devices. This will also significantly increase the cost of the energy storage device, which cannot be compensated by the cost reduction caused by the elimination of fuel costs. In addition, larger-sized energy storage devices will have problematic sustainability effects. Using a smaller energy storage device with insufficient capacity to run for a day will result in the need to charge at a charging station during the day. Since the vehicle stops running when charging, this will increase the total operating cost of the vehicle, and is therefore not suitable for all types of heavy vehicles.

[0005] One option to electrify a wider range of heavy-duty vehicles would be to incorporate a range extender. A range extender typically includes an auxiliary combustion engine that is used only to drive a generator that charges the vehicle's energy storage device. This is sometimes also referred to as a series hybrid powertrain. However, this can result in excessively high emissions, and such powertrains also often suffer from undesirable efficiency losses when converting mechanical energy from the auxiliary combustion engine into electrical energy to be stored. Summary of the invention

[0006] An object of the present disclosure is to provide a cost-effective and energy-efficient (well-to-wheel) solution that can expand the range of electrically drivable vehicles.

[0007] Said object is achieved by the subject-matter of the attached independent claims.

[0008] According to the present disclosure, a vehicle powertrain is provided. The vehicle powertrain includes a motor configured to selectively operate as a motor or a generator. The vehicle powertrain also includes a combustion engine, a planetary gear set, a first shaft, and a second shaft. In addition, the vehicle powertrain includes a coupling arrangement arranged at a first end of the first shaft. The vehicle powertrain also includes a drive shaft connected to at least one drive wheel. The above-mentioned first shaft is connected to the sun gear of the planetary gear set at its second end, and the output shaft of the planetary gear set is connected to the planetary gear carrier of the planetary gear set. The motor is connected to the second shaft. The second shaft can be connected to the first shaft via a coupling arrangement. In addition, the output shaft of the combustion engine can be connected to the first shaft via a coupling arrangement. The second shaft can also be connected to the ring gear of the planetary gear set via a ring gear coupling device. In addition, the ring gear and the sun gear of the planetary gear set are both configured to selectively operate in a rotatable or non-rotatable state.

[0009] The vehicle powertrain described herein is based on an electric vehicle powertrain supplemented with a combustion engine that can be directly connected to the drive shaft when a vehicle including the vehicle powertrain requires a longer range. The vehicle powertrain allows pure electric driving in most possible driving situations while enabling the use of energy storage devices with significantly lower capacity than a battery electric vehicle (BEV) with the same driving range. This in turn, in particular, reduces the added weight and costs of the energy storage device compared to a BEV. This also improves the sustainability impact.

[0010] The fact that the combustion engine can be directly connected to the drive shaft makes it possible to run the combustion engine at a substantially constant load and within a limited speed range (e.g. about 80 km / h to 90 km / h) and to use the electric machine to cycle all transient power requirements. Thus, transient emissions, which may be difficult to limit in other ways, can be avoided and at the same time the combustion engine can be sub-optimized for high energy efficiency.

[0011] Thus, the configuration of the vehicle powertrain allows control such that: (i) at higher power demands at higher driving speeds, the combustion engine continues to operate and the electric motor provides additional power as needed; (ii) at lower power demands at higher driving speeds, the combustion engine continues to operate and the electric motor regenerates excess power; and (iii) at lower or medium driving speeds, the electric motor is used as the sole source of propulsion.

[0012] Furthermore, the vehicle powertrain makes the operation of the vehicle less dependent on the charging infrastructure, since it allows the energy storage device of the vehicle to be charged both when the vehicle is moving and when stationary, without requiring the vehicle to be present at a charging station when the vehicle is stationary. More specifically, when the vehicle is stationary, the vehicle powertrain allows the energy storage device to be charged using a combustion engine, which can perform at a power similar to that of a fast charger. Furthermore, charging while the vehicle is moving can be performed by regenerative braking, but can also be performed by transmitting propulsion torque to the drive wheels and therefore also during acceleration of the vehicle.

[0013] The second shaft may be a hollow shaft, and the first shaft may be arranged to extend through the hollow second shaft. Thus, the configuration of the vehicle powertrain is made more compact in view of the fact that fewer gears and shafts are required.

[0014] The vehicle powertrain may further include a first locking device configured to selectively lock the ring gear of the planetary gear set in a non-rotatable state. This enables the ring gear to reliably operate in a non-rotatable state and enables the ring gear to operate in a rotatable state, depending on the desired operating state of the vehicle powertrain.

[0015] The vehicle powertrain may further include a second locking device configured to selectively lock the output shaft of the combustion engine in a non-rotatable state. In such a case, the sun gear of the planetary gear set may be configured to be locked in a non-rotatable state by connecting the output shaft of the combustion engine to the first shaft via a coupling arrangement when the output shaft of the combustion engine is locked in a non-rotatable state. Therefore, there is no need to arrange any locking device configured to lock the sun gear in a non-rotatable state at or near the planetary gear set, which is generally difficult to accommodate.

[0016] The output shaft of the planetary gear set can be connected to the drive shaft of the vehicle power system via a differential. This has the advantage of making the configuration of the vehicle power system more compact.

[0017] Alternatively, the output shaft of the planetary gear set can be connected to a multi-gear transmission unit, which is connected to the drive shaft of the vehicle powertrain via a differential. Thus, additional gear ratios are enabled.

[0018] The present disclosure also provides a method for controlling the vehicle powertrain described above, executed by a control arrangement. The method comprises, in response to a command to charge an energy storage device (which is configured to power the motor) when a propulsion torque is required to be delivered to the drive shaft in a third gear ratio, the following steps:

[0019] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0020] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0021] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0022] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0023] - operating the electric machine as a generator; and

[0024] -Operating the combustion engine to provide propulsion torque.

[0025] The method described herein allows for efficient charging of an energy storage device while a vehicle including a vehicle powertrain is traveling with propulsion torque provided to the drive wheels. In other words, charging of the energy storage device can be achieved without requiring regenerative braking of the vehicle, which would result in a reduction in travel speed. Furthermore, charging of the energy storage device does not rely on the presence of a separate generator, unlike an electric motor that may also serve as a propulsion unit.

[0026] The method may further include, in response to a command to charge an energy storage device configured to power the electric machine when no propulsion torque is required to be delivered to the drive shaft, the following steps:

[0027] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0028] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0029] - if the ring gear coupling is not already open, controlling the ring gear coupling to an open state;

[0030] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0031] - operating the combustion engine to provide positive output torque, and

[0032] - Operate the motor as a generator.

[0033] As a result, the energy storage device can be charged while the vehicle including the vehicle powertrain is stationary, without the need for charging at a charging station. This also allows the energy storage device to be charged while the vehicle is moving, without the need to transmit propulsion torque to the drive shaft, for example during coasting, and without having to rely on regenerative braking that may result in a reduction in driving speed.

[0034] The method may further include, in response to a command for pure electric driving in the first gear ratio, the following steps:

[0035] - if the ring gear is not already in a non-rotatable state, controlling the ring gear to the non-rotatable state;

[0036] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0037] - if the ring gear coupling is not already open, controlling the ring gear coupling to an open state;

[0038] - controlling the coupling arrangement so as to connect the second shaft to the first shaft if not already connected; and

[0039] - Operate the motor as a motor.

[0040] As a result, the highest possible torque can be transmitted to the drive shaft (and thus also to the drive wheels) without having to use the combustion engine, thus allowing environmentally friendly and energy-saving driving in particular at lower driving speeds or when setting the vehicle including the vehicle powertrain into motion from a standstill.

[0041] The method may further include, in response to a command for purely electric driving in the second gear ratio, the following steps:

[0042] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0043] - if the sun gear is not already in a non-rotatable state, controlling the sun gear to the non-rotatable state;

[0044] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0045] - if not already disconnected, controlling the coupling arrangement so as to disconnect the second shaft from the first shaft; and

[0046] - Operate the motor as a motor.

[0047] This allows, in particular, environmentally friendly and energy-saving driving at relatively low driving speeds, for example during city driving, etc., without having to use the combustion engine which would increase emissions.

[0048] The method may further include, in response to a command for pure electric driving in the third gear ratio, the following steps:

[0049] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0050] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0051] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0052] - controlling the coupling arrangement so as to connect the second shaft to the first shaft if not already connected; and

[0053] - Operate the motor as a motor.

[0054] Thus, environmentally friendly and energy-efficient driving of a vehicle including the vehicle powertrain may be achieved at relatively high driving speeds when the electric machine may provide sufficient propulsion torque to maintain a desired driving speed of the vehicle.

[0055] The method may further include, in response to a command to perform hybrid driving in the first gear ratio, the following steps:

[0056] - if the ring gear is not already in a non-rotatable state, controlling the ring gear to the non-rotatable state;

[0057] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0058] - if the ring gear coupling is not already open, controlling the ring gear coupling to an open state;

[0059] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0060] - operating the electrical machine as a motor; and

[0061] -Operating the combustion engine to provide propulsion torque.

[0062] This allows, in particular, the vehicle including the vehicle powertrain to be set into motion in a steep uphill grade and / or with a heavy load or when traveling at a lower driving speed under such conditions. In such cases, the use of the combustion engine to support the electric machine avoids the need to have to incorporate a more powerful (and therefore more expensive) electric machine in the vehicle powertrain, which may be too large for the most common operating conditions of the vehicle.

[0063] The method may further include, in response to a command to perform hybrid driving in a third gear ratio, the following steps:

[0064] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0065] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0066] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0067] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0068] - operating the electrical machine as a motor; and

[0069] -Operating the combustion engine to provide propulsion torque.

[0070] Thereby, energy-efficient driving of the vehicle including the vehicle powertrain at top travel speeds or at high speeds on steep uphill slopes and / or under high loads can be achieved, since the combustion engine can be operated within its most energy-efficient operating window, which also produces low emissions, while the electric machine is used to support the combustion engine. This also enables the use of a smaller sized energy storage device, thereby reducing costs and reducing the added weight of the vehicle.

[0071] The method may further include, in response to a command to drive the engine in a variable gear ratio, the following steps:

[0072] - if the ring gear is not already in a non-rotatable state, controlling the ring gear to the non-rotatable state;

[0073] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0074] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0075] - controlling the coupling arrangement so as to connect the output shaft of the combustion engine to the first shaft if it is not already connected and to disconnect the second shaft from the first shaft if it is not already disconnected;

[0076] - operating the combustion engine to provide propulsion torque; and

[0077] - The electric machine can be operated variably as a motor or a generator and at different speeds to achieve the desired gear ratio.

[0078] Thus, a variable gear ratio can be achieved by controlling the electric machine so as to influence the gear ratio achieved by the planetary gear set. This can be used, for example, when maneuvering a vehicle including the vehicle powertrain at very low driving speeds.

[0079] The method may further include, in response to a command to regenerate braking of the vehicle powertrain, the following steps:

[0080] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0081] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0082] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0083] - controlling the coupling arrangement in order to connect the second shaft and optionally the output shaft of the combustion engine to the first shaft, if not already connected; and

[0084] - operate the motor as a generator;

[0085] The method optionally further comprises controlling the combustion engine to output a braking torque when an output shaft of the combustion engine is connected to the first shaft.

[0086] This enables efficient charging of the energy storage device in particular when the vehicle comprising the vehicle powertrain is to be braked in order to reduce or at least maintain (in the case of downhill driving) its driving speed.

[0087] The present disclosure also relates to a computer program comprising instructions which, when executed by a computer, cause the computer to perform the method described above.

[0088] The present disclosure also relates to a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method described above.

[0089] In addition, the present disclosure provides a control arrangement configured to control the vehicle powertrain described above. The control arrangement is configured to charge an energy storage device configured to power the motor in response to a command to deliver propulsion torque to the drive shaft in a third gear ratio:

[0090] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0091] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0092] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0093] - controlling the coupling arrangement so as to connect the output shaft and the second shaft of the combustion engine to the first shaft if not already connected; and

[0094] - Operate the motor as a generator.

[0095] The control arrangement provides the same advantages as described above with respect to the corresponding method for controlling a vehicle powertrain described herein.

[0096] The present disclosure also relates to a vehicle comprising the above-mentioned vehicle powertrain and an energy storage device configured to power a motor of the vehicle powertrain. The vehicle may also include the control arrangement described above. The vehicle may be a land heavy vehicle, such as a bus or a truck, but is not limited thereto. According to one embodiment, the vehicle may be a long-distance transport truck.

[0097] In addition, the vehicle may be a vehicle configured to be partially or fully operated by a driver. Such a driver may be present on the vehicle or remotely control the vehicle. Alternatively, the vehicle may be a fully autonomous vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 schematically shows a side view of an example of a vehicle,

[0099] Figure 2 A first exemplary embodiment of a vehicle powertrain described herein is schematically shown,

[0100] Figure 3 A second exemplary embodiment of a vehicle powertrain described herein is schematically shown.

[0101] Figure 4 : represents a flow chart schematically showing an exemplary embodiment of a method for controlling a vehicle powertrain according to the present disclosure described herein,

[0102] Figure 5 An exemplary embodiment of an apparatus is schematically shown, which may comprise, consist of or be comprised in a control arrangement which is configured to perform the method described herein for controlling a vehicle powertrain. DETAILED DESCRIPTION

[0103] The invention will be described in more detail below with reference to exemplary embodiments and the accompanying drawings. However, the invention is not limited to the exemplary embodiments discussed and / or shown in the drawings, but may be varied within the scope of the appended claims. Furthermore, the drawings should not be considered to be drawn to scale, as some features may be exaggerated in order to more clearly illustrate the invention or its features.

[0104] The present disclosure relates to a vehicle powertrain, and a vehicle including the vehicle powertrain. The vehicle powertrain includes an electric motor and a combustion engine, each of which is configured to act as a propulsion unit. Therefore, the vehicle powertrain of the present invention is a hybrid vehicle powertrain, and can be operated, for example, as a parallel hybrid vehicle powertrain. The electric motor is configured to selectively operate as an electric motor or a generator. In addition, the electric motor is configured to be powered by an energy storage device. It should be noted here that such energy storage devices are generally not considered to constitute part of the vehicle powertrain itself, but may be included in a vehicle including the vehicle powertrain. The vehicle powertrain also includes a planetary gear set, which includes a sun gear, a plurality of planetary gears supported by a planetary gear carrier, and a ring gear connected to / supported by a ring gear carrier. The planetary gear carrier is in turn connected to the output shaft of the planetary gear set.

[0105] The vehicle powertrain also includes a first shaft and a second shaft, and a drive shaft connected to one or more drive wheels. Typically, the drive shaft is connected to at least two drive wheels, wherein the two drive wheels are connected to the drive shaft at opposite ends of the drive shaft. The motor is connected to the second shaft of the vehicle powertrain. Thus, the second shaft is configured to be driven by the motor.

[0106] Furthermore, the vehicle powertrain comprises a coupling arrangement configured to selectively connect an output shaft of the combustion engine to the first shaft. The coupling arrangement is further configured to selectively connect the second shaft to the first shaft. The coupling arrangement is arranged at a first end of the first shaft.

[0107] The second end of the first shaft (i.e., the end opposite to the first end of the first shaft) is connected to the sun gear of the planetary gear set. Therefore, the sun gear is configured to rotate with the rotation of the first shaft. In addition, the vehicle powertrain includes a ring gear coupling device, which is configured to selectively connect the second shaft to the ring gear of the planetary gear set.

[0108] Both the ring gear and the sun gear of the planetary gear set can be controlled to operate in a non-rotatable state as well as in a rotatable state. For example, the vehicle powertrain may include a first locking device configured to selectively lock the ring gear of the planetary gear set in a non-rotatable state. The first locking device may be arranged at the ring gear. In addition, when the output shaft of the combustion engine is locked in a non-rotatable state, the sun gear of the planetary gear set may be locked in a non-rotatable state by connecting the first shaft to the output shaft of the combustion engine using a coupling arrangement. The output shaft of the combustion engine may be locked in a non-rotatable state by a second locking device configured thus.

[0109] The second shaft of the vehicle powertrain may suitably be a hollow shaft. In such a case, the first shaft may be arranged inside the hollow second shaft and pass through the hollow second shaft. Thereby, a more compact configuration of the vehicle powertrain may be achieved. The first shaft and the second shaft may be coaxial or at least arranged in parallel.

[0110] The output shaft of the planetary gear set may be directly connected to a differential of the vehicle powertrain, the differential being configured to transfer the propulsion torque to the drive shaft. Alternatively, the output shaft of the planetary gear set may be connected to the differential via a multi-gear transmission unit of the vehicle powertrain. Such a multi-gear transmission unit may be arranged near the drive shaft. With the aid of such a multi-gear transmission unit, additional gear ratios of the vehicle powertrain may be provided.

[0111] With the vehicle powertrain described herein, the capacity of the energy storage device configured to power the motor can be significantly reduced compared to, for example, a pure battery electric vehicle configured to provide the same driving range. This in turn reduces the weight of the vehicle and thereby also increases the possible cargo weight due to the reduced size of the energy storage device. It also reduces the cost of the energy storage device and allows more available space on the vehicle for, for example, cargo.

[0112] In addition, the configuration of the powertrain described herein enables the combustion engine to be operated only within the most energy-efficient operating window of the combustion engine and under relatively stable operating conditions. In contrast, the motor can be used to cycle all transient power requirements. In general, the combustion engine for heavy vehicles is generally less energy efficient at lower speeds and lower torque requirements. The operation of the combustion engine outside the most energy-efficient operating window and the transients in the operation of the combustion engine may lead to increased emissions. However, this can be minimized by the vehicle powertrain described herein.

[0113] As previously mentioned, the present disclosure also provides a vehicle comprising the vehicle powertrain described above. The vehicle may be a heavy vehicle, such as a bus or a truck, but is not limited thereto, and can therefore also be used, for example, for medium-sized trucks. Importantly, the vehicle powertrain described herein provides an excellent solution for the electrification of long-distance transport trucks, which can be operated throughout the long-distance transport cycle without the need to stop at a charging station. Therefore, according to one aspect of the present disclosure, the vehicle is a long-distance transport truck. A long-distance transport truck is considered herein to mean a truck designed to carry heavier loads over long distances, such as 400km or more.

[0114] The present disclosure also relates to a method for controlling a vehicle powertrain as described above. The control may be performed to achieve various operating states of the vehicle powertrain according to desired operating conditions of a vehicle including the vehicle powertrain. Depending on the desired operating state, the method generally comprises the following steps:

[0115] (a) controlling the ring gear of the planetary gear set to a rotatable or non-rotatable state;

[0116] (b) controlling the sun gear of the planetary gear set to a rotatable or non-rotatable state;

[0117] (c) controlling the ring gear coupling device to a closed state or an open state, wherein the closed state connects the second shaft to the ring gear of the planetary gear set and the open state disconnects the second shaft from the ring gear;

[0118] (d) controlling the coupling arrangement so as to connect and / or disconnect one or both of the output shaft of the combustion engine and the second shaft from the first shaft;

[0119] (e) controlling the electric machine to operate as a motor, a generator, or to rotate only with the rotation of the second shaft;

[0120] (f) Controlling the combustion engine to provide positive output torque, negative output torque, or shut down.

[0121] It should be noted here that positive output torque of a combustion engine is also described herein as propulsion torque, and negative torque output of a combustion engine is also referred to herein as brake torque.

[0122] The method described herein for controlling a vehicle powertrain is performed by a control arrangement thus configured.

[0123] More specifically, the method described herein for controlling a vehicle powertrain includes, in response to a command to charge an energy storage device, being configured to power an electric machine when propulsion torque is required to be delivered to a drive shaft in a third gear ratio, the following steps:

[0124] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0125] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0126] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0127] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0128] - operating the electric machine as a generator; and

[0129] -Operating the combustion engine to provide propulsion torque.

[0130] Thus, the method described herein may also include controlling the vehicle powertrain to any of the operating states of the vehicle powertrain in response to the command, as will be described below with respect to Figure 2 An exemplary embodiment of a vehicle powertrain is shown described in greater detail.

[0131] The execution of the method described herein for controlling the vehicle powertrain described herein may be managed by programming instructions. These programming instructions are generally in the form of a computer program that, when executed by a computer, causes the computer to implement a desired form of control action. Such a computer may, for example, be included in the control arrangement described herein. In the present disclosure, a computer is considered to mean any hardware or hardware / firmware device implemented using processing circuits, such as, but not limited to, a processor, a central processing unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a system on a chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit, or any other device capable of electronically performing operations in a defined manner.

[0132] The programming instructions described above, which may be in the form of a computer program, may be stored on a computer-readable medium. Therefore, the present disclosure also relates to a computer-readable medium storing instructions that, when executed by a computer, cause the computer to perform the method for controlling a vehicle powertrain described herein. The computer-readable medium may be a non-transitory computer-readable medium, such as a tangible electronic, magnetic, optical, infrared, electromagnetic and / or semiconductor system, device and / or apparatus.

[0133] The present disclosure also relates to a control arrangement configured to perform the method described herein for controlling a vehicle powertrain described above.The control arrangement may be configured to perform any one of the steps of the method described herein for controlling a vehicle powertrain.

[0134] More specifically, the present disclosure provides a control arrangement configured to control the vehicle powertrain described above. The control arrangement is configured to charge an energy storage device configured to power an electric machine in response to a command to deliver propulsion torque to a drive shaft in a third gear ratio:

[0135] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0136] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0137] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0138] - controlling the coupling arrangement so as to connect the output shaft and the second shaft of the combustion engine to the first shaft if not already connected; and

[0139] - Operate the motor as a generator.

[0140] Figure 1 A side view of an example of a vehicle 1 is schematically shown, which is shown here as a truck. The vehicle 1 comprises a vehicle powertrain 2. The vehicle powertrain 2 comprises a first propulsion unit in the form of an electric motor 3. The electric motor 3 is configured to be powered by an energy storage device 10 of the vehicle when the electric motor 3 operates as an electric motor. For the purpose of charging the energy storage device 10, the electric motor 3 can also be operated as a generator. The vehicle powertrain 2 also comprises a second propulsion unit in the form of a combustion engine 4. The vehicle powertrain 2 also comprises a planetary gear set 5. The output shaft 14 of the planetary gear set 5 is connected to a drive shaft 6, which in turn is connected to a drive wheel 7. The drive shaft 6 and the drive wheel 7 are components of the vehicle powertrain 2.

[0141] The vehicle 1 further comprises a control arrangement 100 configured to control the vehicle powertrain 2. The control arrangement 100 may be configured to perform any one of the steps of the method described herein for controlling a vehicle powertrain 2 according to the present disclosure.

[0142] Figure 2 A first exemplary embodiment of a vehicle powertrain 2 according to the present disclosure is schematically shown. The vehicle powertrain 2 may include, for example, Figure 1 In the vehicle 1 shown.

[0143] The vehicle powertrain 2 comprises a plurality of shafts, including a first shaft 11 and a second shaft 12. The first shaft 11 may alternatively be described as the main shaft of the vehicle powertrain 2. Depending on the operating state of the vehicle powertrain 2, the first shaft 11 and the second shaft 12 may be connected or disconnected from each other by a coupling arrangement 30. The coupling arrangement 30 is arranged at a first end 11a of the first shaft 11. The second shaft 12 may be a hollow shaft, and the first shaft 11 may be arranged to extend longitudinally through the hollow second shaft 12. Thus, the first shaft 11 and the second shaft 12 may be coaxial, or at least substantially arranged in parallel. The plurality of shafts of the vehicle powertrain 2 further comprises a drive shaft 6 to which the drive wheels 7 are connected. In the figure, two drive wheels 7 are shown. However, the vehicle powertrain may include additional drive wheels, such as two drive wheels at each respective end of the drive shaft 6. It is also possible that the vehicle powertrain 2 may include more than one drive shaft 6, each drive shaft being connected to at least two drive wheels 7. In the case of a plurality of drive shafts 6, such drive shafts may be suitably arranged substantially in parallel.

[0144] The vehicle powertrain 2 also includes an electric machine 3. The electric machine 3 is operable as an electric motor for the purpose of generating a propulsion torque transmitted to the drive wheels 7, and for said purpose, the electric motor is configured to be powered by an energy storage device (e.g. Figure 1 The motor 3 is powered by an energy storage device 10 of the vehicle 1 shown in FIG. 1 . For the purpose of converting mechanical energy into electrical energy that can be used to charge the energy storage device, the motor 3 can also operate as a generator. In other words, the motor is configured to selectively operate as a motor or a generator depending on the operating state of the vehicle power system 2. The motor 3 includes a rotor 16 and a stator 17. In addition, the motor 3 is connected to a second shaft 12 of the vehicle power system 2. Therefore, the second shaft 12 of the vehicle power system 2 can be alternatively described as a motor shaft. The second shaft 12 is arranged so that it extends outward on both sides of the motor 3 to allow it to be selectively connected to other components of the vehicle power system 2.

[0145] The vehicle powertrain 2 also includes a combustion engine 4. The combustion engine 4 is configured to generate a propulsion torque that is transmitted to the drive wheels 7. The combustion engine 4 can also be used to generate mechanical energy, which can be used to store energy (e.g. Figure 1 The combustion engine 4 is converted into electrical energy by the motor 3 for the purpose of charging the energy storage device 10 of the vehicle 1 shown in FIG. The combustion engine 4 can also be used to provide braking torque to the vehicle powertrain 2, for example, by engine drag or by engine braking when necessary. The combustion engine 4 includes an output shaft 13, which can be connected to the first shaft 11 and / or the second shaft 12 via a coupling arrangement 30.

[0146] The vehicle powertrain 2 also includes a planetary gear set 5. The planetary gear set 5 includes a sun gear 20, a plurality of planetary gears 21 supported by a planetary gear carrier 22, and a ring gear 23 connected to a ring gear carrier 24. The sun gear 20 is connected to the first shaft 11 of the vehicle powertrain 2 at the second end 11b of the first shaft 11. In other words, the first shaft 11 is arranged to extend longitudinally from the coupling arrangement 30 to the sun gear 20 of the planetary gear set 5. In addition, the ring gear 23 can be connected to the second shaft 12 of the vehicle powertrain 2 via the ring gear carrier 24 through a ring gear coupling device 34. The ring gear coupling device 34 is arranged on the side of the motor 3 opposite to the side where the coupling arrangement 30 is arranged. The ring gear coupling device 34 can be, for example, a friction clutch, a viscous coupling, a dog clutch, or a claw clutch, but is not limited thereto.

[0147] The ring gear 23 of the planetary gear set 5 can be locked in a non-rotatable state by means of a first locking device 25. The first locking device 25 can alternatively be described as a ring gear locking device. When the ring gear 23 is not locked in a non-rotatable state by means of the first locking device 25, the ring gear 23 is in a rotatable state. The ring gear carrier 24 is configured to rotate with the rotation of the ring gear 23.

[0148] Furthermore, the planet carrier 22 is connected to a shaft forming the output shaft 14 of the planetary gear set 5. The output shaft 14 is connected to the drive shaft 6 of the vehicle powertrain 2 via a differential 8.

[0149] As described above, the vehicle powertrain 2 comprises a coupling arrangement 30 arranged at the first end 11a of the first shaft 11. The coupling arrangement 30 is configured to connect and disconnect each of the second shaft 12 and the output shaft 13 of the combustion engine 4 to the first shaft 11. The coupling arrangement 30 can be controlled to four different operating states, namely:

[0150] (i) a first operating state in which each of the first shaft 11, the second shaft 12 and the output shaft 13 of the combustion engine 13 is disconnected from each other,

[0151] (ii) a second operating state, in which the first shaft 11 is connected to the second shaft 12 and the output shaft 13 of the combustion engine is disconnected from each of the first shaft 11 and the second shaft 12,

[0152] (iii) a third operating state in which the output shaft 13 of the combustion engine 4 is connected to the first shaft 11, and the second shaft 12 is disconnected from each of the output shaft 13 and the first shaft 11, and

[0153] (iv) a fourth operating state in which each of the second shaft 12 and the output shaft 13 of the combustion engine 4 is connected to the first shaft, which in turn means that the output shaft 13 is connected to the second shaft 12 .

[0154] The coupling arrangement 30 may comprise a first coupling device 31 and a second coupling device 32. The first coupling device 31 is configured to connect (and disconnect) the output shaft 13 of the combustion engine 4 to the first shaft 11. The second coupling device 32 of the coupling arrangement 30 is configured to connect (and disconnect) the first shaft 11 to the second shaft 12. Each of the first coupling device 31 and the second coupling device 32 may, for example, be selected from the group consisting of: a friction clutch, a viscous coupling, a dog clutch or a claw clutch.

[0155] As mentioned previously, the sun gear 20 of the planetary gear set 5 is configured to selectively operate in a rotatable state or a non-rotatable state. Therefore, the vehicle powertrain 2 also includes a member for locking the sun gear 20 in a non-rotatable state. Figure 2 In the exemplary embodiment shown, this is achieved by a gear 41 arranged on the output shaft 13 of the combustion engine 4, which gear can be locked in a non-rotatable state by a second locking device 42. In other words, the vehicle powertrain 2 comprises a second locking device 42, which is configured to lock the output shaft 13 of the combustion engine in a non-rotatable state. The control coupling arrangement 30 is to connect the output shaft 13 of the combustion engine 4 with the first shaft 11 of the vehicle powertrain 2, while the output shaft 13 of the combustion engine 4 is locked in a non-rotatable state by means of the second locking device 42, thereby inherently locking the sun gear 20 in a non-rotatable state.

[0156] It should be noted that although Figure 2 The vehicle powertrain 2 shown in has a configuration in which the first shaft 11 extends longitudinally within and through the hollow second shaft 12, but other configurations in which the first shaft 11 and the second shaft 12 are arranged side by side are also possible. However, such a configuration would require an additional gear arrangement and shaft to enable the second shaft 12 to be connected to the coupling arrangement 30 and the ring gear coupling device, which in turn would, for example, result in a larger vehicle powertrain 2.

[0157] In the following, the Figure 2 . These operating states are achieved by respectively controlling the coupling device 30 and the ring gear coupling device 34 to connect / disconnect with different shafts of the vehicle powertrain 2; controlling each of the sun gear 20 and the ring gear 23 of the planetary gear set 5 to be in a rotatable or non-rotatable state; and operating the electric machine 3 (as a motor or as a generator) and / or the combustion engine 4 to provide propulsion or braking torque.

[0158] Pure electric drive in first gear ratio

[0159] In pure electric drive in the first gear ratio, the ring gear 23 is controlled to be in a non-rotatable state, while the sun gear 20 is controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in an open state, whereby the second shaft 12 is disconnected from the ring gear carrier 24 and thereby also disconnected from the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the first shaft 11 to the second shaft 12. By operating the electric machine 3 as an electric motor, the propulsion torque will be transmitted from the second shaft 12 to the sun gear 20 of the planetary gear set 5 via the first shaft 11. The propulsion torque is transmitted from the sun gear 20 to the planetary gear carrier 22 and the output shaft 14 of the planetary gear set 5 via the planetary gear 21, and thereafter transmitted to the drive shaft 6 via the differential 8.

[0160] In this operating state, the output shaft 13 of the combustion engine 4 is normally disconnected from the first shaft 11 by means of the control coupling arrangement 30. Any braking torque caused by engine drag is thereby avoided from being applied to the vehicle powertrain 2.

[0161] For example, when the vehicle is set in motion and at a low driving speed, the above described operating state of pure electric drive in the first gear ratio can be used. This operating state can result in the highest torque at the drive wheels 7 when the vehicle powertrain 2 is running in pure electric drive.

[0162] Pure electric drive in second gear ratio

[0163] In order to obtain a purely electric drive in the second gear ratio, the ring gear 23 is controlled to be in a rotatable state, while the sun gear 20 is controlled to be in a non-rotatable state. The sun gear 20 can be controlled to be in the non-rotatable state by locking the output shaft 13 of the combustion engine 4 in a non-rotatable state using the second locking device 42 and controlling the coupling arrangement 30 to connect the output shaft 13 of the combustion engine 4 to the first shaft 11. The coupling arrangement 30 is also controlled so that the second shaft 12 is disconnected from the first shaft 11. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear carrier 24 and thereby also to the ring gear 23. By operating the electric machine 3 as an electric motor, the propulsion torque will be transmitted from the second shaft 12 to the ring gear 23 of the planetary gear set 5. The propulsion torque is transmitted from the ring gear 23 to the planetary gear carrier 22 and the output shaft 14 of the planetary gear set 5 (via the planetary gears 21), and further transmitted to the drive shaft 6 and the associated drive wheels 7 via the differential 8.

[0164] For example, the electric drive operating state in the second gear ratio may be used at relatively low driving speeds, such as during city driving or the like.

[0165] Pure electric drive in third gear ratio

[0166] In order to obtain a purely electric drive in the third gear ratio, both the ring gear 23 and the sun gear 20 are controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear carrier 24, and thereby also to the ring gear 23. In addition, the coupling arrangement is controlled to connect the second shaft 12 with the first shaft 11. By operating the electric machine 3 as a motor, the propulsion torque will be transmitted from the second shaft 12 to the ring gear 23 of the planetary gear set 5, and from the second shaft 12 to the first shaft 11 via the coupling arrangement 30, and thus also to the sun gear 20. In view of the fact that the propulsion torque is transmitted to the ring gear 23 and the sun gear 20 of the planetary gear set 5, the planetary gear carrier will be locked to rotate with the ring gear 23 and the sun gear 20. This creates a direct gear for a purely electric drive of the vehicle powertrain 2.

[0167] Furthermore, the coupling arrangement 30 can be appropriately controlled to disconnect the output shaft 13 of the combustion engine 4 from the first shaft 11 (and thereby also from the second shaft 12) to avoid any braking torque on the vehicle powertrain 2 caused by engine drag. However, in the case where it is necessary to discharge an energy storage device configured to power the motor, for example because it is predicted that the energy storage device has too high a state of charge to achieve regenerative braking during an upcoming braking event, it may be reasonable to connect the output shaft 13 of the combustion engine 4 to the first shaft 11 and the second shaft 12 by controlling the coupling arrangement 30. As a result, the energy consumption of the motor 3 can be increased to compensate for the braking torque applied by the combustion engine 4 on the vehicle powertrain 2. Such braking torque can be applied by engine drag or by engine braking. Engine braking is considered in this article to mean running the combustion engine 4 to output braking torque, for example by using an exhaust brake, a compression release brake or a variable vane brake. During engine drag, the combustion engine 4 is controlled to a passive state and a braking torque is applied on the vehicle powertrain 2 due to the energy required to rotate the combustion engine 4.

[0168] For example, the electric drive operating state in the third gear ratio may be used at higher driving speeds when the propulsion torque provided by the motor 3 is sufficient to maintain such higher driving speeds.

[0169] Regenerative braking

[0170] In order to brake the vehicle powertrain 2 by regenerative braking, the ring gear 23 and the sun gear 20 are both controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear carrier 24, and thereby also to the ring gear 23. In addition, the coupling arrangement is controlled to connect the second shaft 12 with the first shaft 11. Subsequently, by operating the motor 3 as a generator, a braking torque will be applied to the vehicle powertrain 2 due to the conversion of mechanical energy into electrical energy realized by the motor 3. The electrical energy generated by the motor 3 can be stored in the energy storage device so as to power the motor when the motor 3 is operated as a motor.

[0171] Depending on the amount of braking torque desired, the coupling arrangement 30 can be controlled so as to connect the output shaft 13 of the combustion engine 4 to the first shaft 11 or disconnect it from said first shaft. When the output shaft 13 of the combustion engine 4 is disconnected from the first shaft 11, the combustion engine 4 is not used to apply any braking torque to the vehicle powertrain 2. However, when the output shaft 13 of the combustion engine 4 is connected to the first shaft 11, the combustion engine can be used to further increase the braking torque applied to the vehicle powertrain 2 by engine drag or by engine braking. As previously mentioned, engine braking is taken herein to mean operating the combustion engine to output braking torque, for example by using an exhaust brake, a compression release brake or a variable vane brake.

[0172] Hybrid drive in first gear ratio

[0173] In order to obtain a hybrid drive in the first gear ratio, the ring gear 23 is controlled to be in a non-rotatable state, while the sun gear 20 is controlled to be in a rotatable state. In addition, the ring gear coupling device is controlled to an open state, whereby the second shaft 12 is disconnected from the ring gear 23 of the planetary gear set 5. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. By operating the combustion engine 4 and the electric machine 3 to provide a propulsion torque (for the electric machine 3, this means that the electric machine operates as an electric motor), the propulsion torque will be transmitted from the electric machine 3 and the combustion engine 4 to the first shaft 11, and thus to the sun gear 20 of the planetary gear set 5. The propulsion torque is transmitted from the sun gear 20 to the planetary gear carrier 22 and the output shaft 14 of the planetary gear set 5 via the planetary gear 21, and further transmitted to the drive shaft 6 via the differential 8.

[0174] For example, the operating state of hybrid drive in the first gear ratio may be used when setting the vehicle to travel on a steep uphill slope or to travel at a lower driving speed on a steep uphill slope. The combustion engine may be considered herein as supporting the electric machine to ensure sufficient propulsion torque - this operating state may result in the highest propulsion torque at the drive wheels 7 when the vehicle powertrain 2 is operated in hybrid drive.

[0175] Hybrid drive in third gear ratio

[0176] In order to obtain a hybrid drive in the third gear ratio, both the ring gear 23 and the sun gear 20 are controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear carrier 24, and thereby also to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11.

[0177] By operating the combustion engine 4 and the electric machine 3 to provide propulsion torque (for the electric machine 3 this means that the electric machine operates as an electric motor), the propulsion torque will be transmitted to the ring gear 23 of the planetary gear set 5 via the second shaft 12, and to the first shaft 11 via the coupling arrangement 30, and thus also to the sun gear 20. In view of the fact that the propulsion torque is transmitted to the ring gear 23 and the sun gear 20 of the planetary gear set 5, the planetary gear carrier will be locked to rotate with the ring gear 23 and the sun gear 20. This creates a direct gear for the hybrid drive of the vehicle powertrain 2.

[0178] For example, the operating state of the hybrid drive in the third gear ratio can be used at a maximum driving speed of, for example, above 80 km / h, or when driving at a high driving resistance, for example when driving at high speed on a steep uphill slope.

[0179] Pure engine drive in third gear ratio

[0180] In order to obtain pure engine drive in the third gear ratio, both the ring gear 23 and the sun gear 20 are controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear carrier 24 and thereby also to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. In this operating state, the electric machine 3 is not energized, but is allowed to rotate due to the rotation of the second shaft 12. The propulsion torque generated by the combustion engine will be transmitted to the ring gear via the second shaft 12, and to the sun gear 20 of the planetary gear set 5 via the first shaft 11. In view of the fact that the propulsion torque is transmitted to the ring gear 23 and the sun gear 20 of the planetary gear set 5, the planet gear carrier 22 will be locked to rotate with the ring gear 23 and the sun gear 20. This creates a direct gear for pure engine drive of the vehicle powertrain 2. The propulsion torque is transmitted from the planet gear carrier 22 and the output shaft 14 of the planetary gear set 5 to the drive shaft 6 via the differential 8.

[0181] For example, a purely engine-driven operating state in the third gear ratio can be used at higher driving speeds, such as about 80-90 km / h, where the combustion engine can be operated at or near its most energy-efficient operating window. This is the most energy-efficient driving mode for extended driving at a relatively stable driving speed for a heavy vehicle with relatively low emissions. Compared with electric driving under such driving conditions, the most energy-efficient driving mode also enables the use of a smaller-sized energy storage device and thereby achieves less added weight and cost.

[0182] It should be noted here that the term "engine-only" is used herein to describe an operating condition in which the vehicle powertrain is driven solely by the combustion engine, without the electric machine operating as a motor or generator.

[0183] Providing propulsion torque to the drive shaft while charging the energy storage device

[0184] Charging of the energy storage device 10 , which is configured to power the electric machine 3 while still delivering propulsion torque to the drive shaft 6 and associated drive wheels 7 , may be performed using two different operating states of the vehicle powertrain.

[0185] According to the first alternative, the propulsion torque is transmitted to the drive shaft 6 in a third gear ratio. This can be achieved by controlling each of the ring gear 23 and the sun gear 20 to a rotatable state and controlling the ring gear coupling device 34 to a closed state, whereby the second shaft 12 is connected to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. By operating the combustion engine 4 to output the propulsion torque, a portion of the energy generated by the combustion engine can be converted into electrical energy by operating the motor 3 as a generator. The electrical energy generated by the motor can be used to charge the energy storage device 10. The remaining portion of the propulsion torque that is not consumed by the motor 3 is transmitted to the drive shaft 6 and the associated drive wheel 7 via the planetary gear set 5. For example, the first alternative can be used at higher driving speeds of a vehicle including the vehicle powertrain 2.

[0186] According to the second alternative, the propulsion torque is transmitted to the drive shaft 6 in the first gear ratio. This can be achieved by controlling the ring gear 23 to be in a non-rotatable state and the sun gear 20 to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to an open state, whereby the second shaft 12 is disconnected from the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. Similar to the first alternative described above, the combustion engine 4 is operated to output the propulsion torque. Thus, part of the energy generated by the combustion engine can be converted into electrical energy by operating the motor 3 as a generator. The electrical energy generated by the motor 3 can be used to charge the energy storage device 10. The remaining part of the propulsion torque generated by the combustion engine 4 and not consumed by the motor 3 is transmitted to the drive shaft 6 and the associated drive wheel 7 via the planetary gear set 5. For example, the second alternative can be used at a lower driving speed of a vehicle including the vehicle powertrain 2.

[0187] The energy storage device is charged when no propulsion torque (or braking torque) is required to be transmitted to the drive shaft

[0188] In order to be able to charge the energy storage device 10 configured to power the motor 3, both the ring gear 23 and the sun gear 20 can be controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to an open state so that the second shaft 12 is disconnected from the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. By operating the combustion engine 4 to generate a positive output torque, the energy generated by the combustion engine 4 can be converted into electrical energy by operating the motor 3 as a generator.

[0189] It should be noted here that the positive output torque of the combustion engine corresponds to the propulsion torque of the combustion engine. However, since the torque generated by the combustion engine is not used to provide propulsion to the drive shaft, the term "positive output torque" is used instead.

[0190] This operating state may be used, for example, when the vehicle including the vehicle powertrain 2 is stationary, or when the vehicle is moving and there is no need to transmit propulsion torque (or braking torque) to the drive shaft 6 and its associated drive wheels 7 .

[0191] Alternatively, when the vehicle including the vehicle powertrain 2 is stationary, the charging of the energy storage device 10 configured to power the motor 3 can be achieved as follows. The ring gear 23 and the sun gear 20 are both controlled to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state, whereby the second shaft 12 is connected to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 to the first shaft 11, but disconnect the second shaft 12 from the first shaft 11. In addition, the drive shaft 6 is controlled to a non-rotatable state. This can be achieved, for example, by using a service brake to lock the drive wheel 7 from rotating, thereby also locking the drive shaft 6. Controlling the drive shaft 6 to a non-rotatable state also means that the planetary gear carrier 22 will be controlled to a non-rotatable state. The combustion engine 4 is then controlled to apply a positive torque, and the motor 3 operates as a generator. As a result, the mechanical energy from the combustion engine 4 can be converted into electrical energy by the motor 3, which can be stored in the energy storage device 10.

[0192] Engine drive with variable gear ratio

[0193] In certain situations, it may be desirable to operate the vehicle powertrain 2 in an operating mode via a variable gear ratio. This may be performed, for example, for the purpose of using an overdrive for the combustion engine so that the combustion engine can operate in a more efficient operating window. Alternatively, when maneuvering a vehicle including the vehicle powertrain 2 at very low driving speeds, it may be desirable for the combustion engine to be able to operate in a more efficient operating window.

[0194] In this operating state, the ring gear 23 is controlled to a non-rotatable state, while the sun gear 20 is controlled to a rotatable state. In addition, the ring gear coupling device 34 is controlled to a closed state so as to connect the second shaft 12 to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 to the first shaft 11, and to disconnect the second shaft 12 from the first shaft 11. The combustion engine 4 is operated to provide propulsion torque, while the electric machine 3 is controlled to provide various positive or negative torques (by operating as a motor or a generator) and / or speeds to the ring gear 23, thereby achieving a variable gear ratio.

[0195] Emissions from energy storage devices

[0196] In certain circumstances, it may be desirable to discharge the energy storage device 10 configured to power the motor, for example due to a prediction that the energy storage device 10 has an excessively high state of charge and that sufficient regenerative braking will not be achieved during an upcoming braking event. The discharge of the energy storage device 10 may be achieved by controlling the vehicle powertrain 2 so that the motor 3 is able to consume more energy than is required to provide the desired propulsion torque to the drive shaft 6 and associated drive wheels 7. In such circumstances, the discharge is performed while the vehicle is moving. However, if desired, the energy storage device 10 may also be discharged while the vehicle is stationary.

[0197] According to a first alternative, the discharge of the energy storage device can be achieved as described above with respect to the operating state of the electric drive in the third gear ratio. According to a first alternative, the discharge is performed while the vehicle 1 is moving.

[0198] According to a second alternative, the discharge of the energy storage device 10 can be achieved by controlling the ring gear 23 and the sun gear 20 to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to an open state so that the second shaft 12 is disconnected from the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. The motor then operates as a motor, but does not transmit any propulsion torque to the drive shaft 6. The motor 3 can be controlled to compensate for the braking torque provided by the combustion engine 4 by allowing the combustion engine to provide braking torque to the vehicle powertrain 2 (as a result of engine drag) or by controlling the combustion engine 4 to provide braking torque by using, for example, an exhaust brake, a compression release brake or a variable vane brake. Thus, the discharge of the energy storage device 10 can be achieved. The discharge according to the second alternative can be performed when the vehicle 1 including the vehicle powertrain 2 is stationary, or when the vehicle is moving without the need to transmit propulsion torque to the drive shaft 6.

[0199] According to a third alternative, the discharge of the energy storage device 10 can be achieved by controlling the ring gear 23 and the sun gear 20 to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to be in a closed state so that the second shaft 12 is connected to the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 to the first shaft 11, but disconnect the second shaft 12 from the first shaft 11. In addition, the drive shaft 6 is controlled to a non-rotatable state. This can be achieved, for example, by using a service brake to lock the drive wheel 7 from rotating, thereby also locking the drive shaft 6. Controlling the drive shaft 6 to a non-rotatable state also means that the planetary gear carrier 22 will be controlled to a non-rotatable state. The motor then operates as a motor and is controlled to compensate for the braking torque applied by the combustion engine through engine drag or engine braking. Thus, the discharge of the energy storage device 10 can be achieved when the vehicle is stationary.

[0200] According to a fourth alternative, the discharge of the energy storage device 10 can be achieved by controlling the ring gear 23 to be in a non-rotatable state and the sun gear 20 to be in a rotatable state. In addition, the ring gear coupling device 34 is controlled to an open state, whereby the second shaft 12 is disconnected from the ring gear 23. In addition, the coupling arrangement 30 is controlled to connect the output shaft 13 of the combustion engine 4 and the second shaft 12 to the first shaft 11. The motor then operates as a motor in order to transmit the propulsion torque to the drive shaft 6. In addition, the combustion engine 4 is controlled to apply a braking torque on the vehicle powertrain 2, which must be compensated by the motor 3. As a result, the motor 3 will consume more energy from the energy storage device 10 than the energy precisely required for the intended propulsion of the vehicle, which in turn leads to the discharge of the energy storage device 10. As is apparent from the above, the discharge of the energy storage device 10 is performed according to the fourth alternative when the vehicle including the vehicle powertrain 2 is traveling.

[0201] It should be noted here that Figure 2 The above-described operating conditions of the vehicle powertrain 2 are not intended to constitute an exhaustive list of operating conditions of a vehicle powertrain according to the present disclosure.

[0202] Controlling the vehicle powertrain 2 to each of the above operating states may be performed in response to commands for such operating states of the vehicle powertrain 2. Thus, the commands may be generated according to any previously known method, such as by a driver of a vehicle including the vehicle powertrain or by any control system (including a control arrangement) of said vehicle.

[0203] Figure 3 A second exemplary embodiment of a vehicle powertrain 2 according to the present disclosure is schematically shown. The second exemplary embodiment corresponds to the one described above and in Figure 2 The first exemplary embodiment is shown in , with the difference that the vehicle powertrain 2 further comprises a multi-gear transmission unit 15 .

[0204] The multi-gear transmission unit 15 may be arranged between the planetary gear set 5 and the differential 8. In other words, the output shaft 14 of the planetary gear set 5 may be connected to the multi-gear transmission unit 15, and the multi-gear transmission unit 5 is further connected to the drive shaft 6 via the differential 8. The purpose of the multi-gear transmission unit 15 is to enable the propulsion torque to be transmitted to the drive shaft 16 with more gear ratios, and thus also to the drive wheels 7. The multi-gear transmission unit 15 may be, for example, a two-stage transmission unit or a three-stage transmission unit, but is not limited thereto.

[0205] According to different operating conditions, Figure 1 The exemplary embodiment of the vehicle powertrain shown is controlled in the same manner as described above according to Figure 3The vehicle powertrain 2 of the second exemplary embodiment is shown. However, the vehicle powertrain may be controlled to transmit the propulsion torque to the drive shaft 6 at another gear ratio by controlling the multi-gear transmission unit 15 .

[0206] Figure 4 Schematically shows a flow chart of an exemplary embodiment of a method for controlling a vehicle powertrain according to the present disclosure described herein, such as Figure 2 An exemplary embodiment of a vehicle powertrain is shown or Figure 3 An exemplary embodiment of a vehicle powertrain in .

[0207] The method comprises a first step S101 of determining whether a command has been generated for charging an energy storage device when it is required to transmit propulsion torque to the drive shaft in a third gear ratio. The energy storage device is an energy storage device configured to power the motor when the motor is operated as a motor. If such a command has not been generated, the method may be restored to the beginning. However, if such a command has been generated, the method proceeds to a subsequent step.

[0208] The method comprises step S102: if not already in a rotatable state, controlling the ring gear of the planetary gear set to the rotatable state.

[0209] The method further comprises step S103: if it is not in the rotatable state yet, controlling the sun gear of the planetary gear set to be in the rotatable state.

[0210] The method further comprises step S104: if not already in the closed state, controlling the ring gear coupling device to the closed state.

[0211] Furthermore, the method comprises a step S105 of controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft of the vehicle powertrain, if not already connected.

[0212] It should be noted here that although steps S102 to S105 are shown in the figure as consecutive steps and performed in a specific order for clarity, these steps may be performed substantially in parallel or in any order without departing from the present disclosure.

[0213] The method further comprises a step S106 of operating the electric machine as a generator, and a step S107 of operating the combustion engine to provide propulsion torque. Thus, the energy storage device can be charged while the propulsion torque is transmitted to the drive shaft. Steps S106 and S107 are usually performed substantially in parallel, and can each be started after steps S102 to S105 are completed, unless the electric machine and / or the combustion engine are already operating according to steps S106 and S107.

[0214] Thereafter, the method may return to the beginning.

[0215] Figure 5 Schematically shown is an exemplary embodiment of a device 500. The control arrangement 100 described above may, for example, comprise the device 500, consist of the device 500 or be comprised in the device 500.

[0216] The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read / write memory 550. The non-volatile memory 520 has a first memory element 530 in which a computer program such as an operating system is stored to control the functions of the arrangement 500. The device 500 also comprises a bus controller, a serial communication port, an I / O device, an A / D converter, a time and date input and transmission unit, an event counter and an interrupt controller (not depicted). The non-volatile memory 520 also has a second memory element 540.

[0217] A computer program P is provided, which includes instructions for controlling a vehicle powertrain. The vehicle powertrain includes an electric machine configured to selectively operate as a motor or a generator. The vehicle powertrain also includes a combustion engine, a planetary gear set, a first shaft and a second shaft. In addition, the vehicle powertrain includes a coupling arrangement arranged at a first end of the first shaft. The vehicle powertrain also includes a drive shaft connected to at least one drive wheel. The above-mentioned first shaft is connected to the sun gear of the planetary gear set at its second end, and the output shaft of the planetary gear set is connected to the planetary gear carrier of the planetary gear set. The motor is connected to the second shaft. The second shaft can be connected to the first shaft via a coupling arrangement. In addition, the output shaft of the combustion engine can be connected to the first shaft via a first coupling arrangement. The second shaft can also be connected to the ring gear of the planetary gear set via a ring gear coupling device. In addition, the ring gear and the sun gear of the planetary gear set are both configured to selectively operate in a rotatable or non-rotatable state. The computer program includes instructions for responding to a command to charge an energy storage device configured to power the motor when it is necessary to transmit propulsion torque to the drive shaft in a third gear ratio:

[0218] - if the ring gear is not already in a rotatable state, controlling the ring gear to the rotatable state;

[0219] - if the sun gear is not already in a rotatable state, controlling the sun gear to the rotatable state;

[0220] - if the ring gear coupling is not already closed, controlling the ring gear coupling to a closed state;

[0221] - controlling the coupling arrangement in order to connect the output shaft of the combustion engine and the second shaft to the first shaft, if not already connected;

[0222] - operating the electric machine as a generator; and

[0223] -Operating the combustion engine to provide propulsion torque.

[0224] The program P may be stored in the storage 560 and / or the read / write memory 550 in an executable form or a compressed form.

[0225] The data processing unit 510 may perform one or more functions, ie, the data processing unit 510 may implement a portion of the program P stored in the memory 560 or a portion of the program P stored in the read / write memory 550 .

[0226] The data processing device 510 can communicate with the data port 599 via a data bus 515. The non-volatile memory 520 is intended to communicate with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. The read / write memory 550 is adapted to communicate with the data processing unit 510 via a data bus 514. The communication between the components can be achieved by a communication link. The communication link can be a physical connection (such as an optical communication line), or a non-physical connection (such as a wireless connection, for example a radio link or a microwave link).

[0227] As data are received on the data port 599, they may be temporarily stored in the second memory element 540. When the received input data has been temporarily stored, the data processing unit 510 is ready to implement code execution as described above.

[0228] Parts of the methods described herein may be implemented by the apparatus 500 through the data processing unit 510 running a program stored in the memory 560 or the read / write memory 550. When the apparatus 500 runs the program, the methods described herein are executed.

Claims

1. A vehicle powertrain (2), comprising: - an electric machine (3) configured to selectively operate as a motor or as a generator, - a combustion engine (4), - a planetary gear set (5), - a first axis (11), - a second shaft (12), - a coupling arrangement (30) arranged at the first end (11a) of the first shaft (11), and - a drive shaft (6) connected to at least one drive wheel (7), in The first shaft (11) is connected to the sun gear (20) of the planetary gear set (5) at a second end (11b) of the first shaft (11), The output shaft (14) of the planetary gear set (5) is connected to the planetary gear carrier (22) of the planetary gear set (5). The motor (3) is connected to the second shaft (12), The second shaft (12) is connectable to the first shaft (11) via the coupling arrangement (30), The output shaft (13) of the combustion engine (4) is connectable to the first shaft (11) via the coupling arrangement (30), and The second shaft (12) is connectable to the ring gear (23) of the planetary gear set (5) via a ring gear coupling device (34), The ring gear (23) and the sun gear (20) of the planetary gear set (5) are both configured to selectively operate in a rotatable or non-rotatable state.

2. The vehicle powertrain (2) according to claim 1, wherein the second shaft (12) is a hollow shaft, and the first shaft (11) is arranged to extend through the hollow second shaft (12).

3. The vehicle powertrain (2) according to any one of claims 1 or 2, further comprising a first locking device (25), which is configured to selectively lock the ring gear (23) of the planetary gear set (5) in the non-rotatable state.

4. A vehicle powertrain (2) according to any one of the preceding claims, further comprising a second locking device (42) configured to selectively lock the output shaft (13) of the combustion engine (4) in a non-rotatable state, and The sun gear (20) of the planetary gear set (5) is configured to be locked in a non-rotatable state when the output shaft (13) of the combustion engine (4) is locked in the non-rotatable state by connecting the output shaft (13) of the combustion engine to the first shaft (11) via the coupling arrangement (30).

5. The vehicle powertrain (2) according to any one of the preceding claims, wherein the output shaft (14) of the planetary gear set (5) is connected to a drive shaft (6) of the vehicle powertrain (2) via a differential (8).

6. The vehicle powertrain (2) according to any one of claims 1 to 5, wherein the output shaft (14) of the planetary gear set (5) is connected to a multi-gear transmission unit (15), and the multi-gear transmission unit (15) is further connected to the drive shaft (6) of the vehicle powertrain (2) via a differential (8).

7. A method for controlling a vehicle powertrain (2) according to any one of the preceding claims, performed by a control arrangement (100), the method comprising: In response to a command to charge the energy storage device (10) when it is necessary to transmit propulsion torque to the drive shaft (6) in a third gear ratio, the energy storage device (10) is configured to power the motor (3): - if the ring gear (23) is not already in the rotatable state, controlling (S102) the ring gear to the rotatable state; - if the sun gear (20) is not already in the rotatable state, controlling (S103) the sun gear to the rotatable state; - if the ring gear coupling device (34) is not yet closed, controlling (S104) the ring gear coupling device to a closed state; - if not already connected, controlling (S105) the coupling arrangement (30) so as to connect the output shaft (13) and the second shaft (12) of the combustion engine to the first shaft (11); - operating the electric machine (3) as a generator; as well as - operating the combustion engine (4) to provide propulsion torque.

8. The method of claim 7, further comprising, in response to a command to charge the energy storage device (10), the energy storage device being configured to power the motor (3) when no propulsion torque is required to be delivered to the drive shaft (6): - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling device (34) is not already open, controlling the ring gear coupling device to an open state; - controlling the coupling arrangement (30) so as to connect the output shaft (13) and the second shaft (12) of the combustion engine to the first shaft (11), if not already connected; - operating said combustion engine to provide a positive output torque, and - operating the electric machine (3) as a generator.

9. The method of claim 7 or 8, further comprising, in response to a command for pure electric driving in the first gear ratio: - if the ring gear (23) is not already in the non-rotatable state, controlling the ring gear to the non-rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling device (34) is not already open, controlling the ring gear coupling device to an open state; - controlling the coupling arrangement (30) so as to connect the second shaft to the first shaft if not already connected; as well as - operating the electrical machine (3) as an electric motor.

10. The method of any one of claims 7 to 9, further comprising, in response to a command for purely electric driving in the second gear ratio: - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the non-rotatable state, controlling the sun gear to the non-rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - if not already disconnected, controlling the coupling arrangement (30) so as to disconnect the second shaft (12) from the first shaft (11); as well as - operating the electrical machine (3) as an electric motor.

11. The method of any one of claims 7 to 10, further comprising in response to a command for pure electric driving in the third gear ratio: - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - if not already connected, controlling the coupling arrangement (30) so as to connect the second shaft (12) to the first shaft (11); and - operating the electrical machine (3) as an electric motor.

12. The method of any one of claims 7 to 11, further comprising, in response to a command to hybrid drive in a first gear ratio: - if the ring gear (23) is not already in the non-rotatable state, controlling the ring gear to the non-rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling device (34) is not already open, controlling the ring gear coupling device to an open state; - controlling the coupling arrangement so as to connect the output shaft (13) and the second shaft (12) of the combustion engine to the first shaft (11), if not already connected; - operating the electrical machine (3) as a motor; and - operating the combustion engine (4) to provide propulsion torque.

13. The method of any one of claims 7 to 12, further comprising in response to a command to hybrid drive in a third gear ratio: - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - controlling the coupling arrangement (30) so as to connect the output shaft (13) and the second shaft (12) of the combustion engine to the first shaft (11), if not already connected; - operating the electrical machine (3) as a motor; and - operating the combustion engine (4) to provide propulsion torque.

14. The method of any one of claims 7 to 13, further comprising in response to a command to drive the engine in a variable gear ratio: - if the ring gear (23) is not already in the non-rotatable state, controlling the ring gear to the non-rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - controlling the coupling arrangement (30) so as to connect the output shaft (13) of the combustion engine to the first shaft (11) if not already connected, and to disconnect the second shaft (12) from the first shaft (11) if not already disconnected; - operating the combustion engine (4) to provide propulsion torque; as well as - The electric machine (3) can be operated variably as a motor or a generator and at different speeds to achieve the desired gear ratio.

15. The method according to any one of claims 7 to 14, further comprising in response to a command to regenerate braking of the vehicle powertrain (2): - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - controlling the coupling arrangement (30) so as to connect the second shaft (12) and optionally the output shaft (13) of the combustion engine (4) to the first shaft (11), if not already connected; and - operating the electric machine (3) as a generator; The method optionally further comprises controlling the combustion engine (4) to output a braking torque when the output shaft (13) of the combustion engine (4) is connected to the first shaft (11).

16. A computer program comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 7 to 15.

17. A computer readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 7 to 15.

18. A control arrangement (100) configured to control a vehicle powertrain (2) according to any one of claims 1 to 6, wherein the control arrangement (100) is configured to, in response to a command to charge the energy storage device (10) when it is required to deliver propulsion torque to the drive shaft (6) in a third gear ratio: - if the ring gear (23) is not already in the rotatable state, controlling the ring gear to the rotatable state; - if the sun gear (22) is not already in the rotatable state, controlling the sun gear to the rotatable state; - if the ring gear coupling (34) is not already closed, controlling the ring gear coupling to a closed state; - controlling the coupling arrangement (30) so as to connect the output shaft (13) and the second shaft (12) of the combustion engine (4) to the first shaft (11), if not already connected; and - operating the electric machine (3) as a generator.

19. A vehicle (1) comprising: A vehicle powertrain (2) according to any one of claims 1 to 6, and an energy storage device (10) configured to supply power to the electric machine (3) of the vehicle powertrain (2), The vehicle (1) optionally further comprises a control arrangement (100) according to claim 18.

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