Hybrid power self-propelled combine harvester

Abstract

A self-propelled combine harvester includes an internal combustion engine and at least a first electric machine mechanically connected to the internal combustion engine and adapted to convert mechanical power generated by the internal combustion engine into electrical power. A storage system for energy generated by the first electric machine is also provided. A first continuously variable mechanical transmission connects the internal combustion engine to a first functional unit and in combination with a second electric machine configured to operate at least in motor mode and electrically connected to the storage system to receive electrical energy from the storage system. A control unit of the combine harvester is configured to control the first motor and the second motor according to operating parameters of the first functional unit.

Description

Field of the Invention

[0001] The present invention relates to improvements in agricultural machinery, and more particularly to improvements in self-propelled combine harvesters. Background Art

[0002] A self-propelled combine harvester is a machine that incorporates various functional units internally, where the functional units perform different functions and include corresponding working members. Although these functions and related members are not synchronized with each other, they are still interconnected and associated through the flow of the material that is first harvested and then processed. In a self-propelled combine harvester, the following basic functions can be listed: forward movement on the ground; harvesting, i.e., cutting and collecting the material from the field; threshing, i.e., separating the grains from the remaining parts of the plants; collecting and unloading the grains.

[0003] The structure of modern self-propelled combine harvesters includes a high-power internal combustion engine that operates at a fixed rotational speed usually close to its maximum power, and drives mechanical couplings that distribute the power to pumps, pulleys, and drive shafts, which in turn drive the various components of the machine. For reasons of optimizing the material flow and balancing the weight, the internal combustion engine is usually located at the rear of the machine. This results in the need to transmit power from the rear part of the combine harvester to the front part using a relatively long and articulated kinematic chain.

[0004] Forward movement, i.e., movement on the ground, is achieved through a hydrostatic transmission with a variable-displacement pump and motor, which allows changing the forward movement speed of the combine harvester independently of the rotational speed of the internal combustion engine. These components also have the advantage of limited weight compared to the transmitted power and allow transmitting the power from the couplings to the axles in a relatively simple manner via hydraulic pipes.

[0005] Harvesting is carried out by a cutting table mounted on the front part of the machine. Depending on the type of material to be harvested (wheat, corn, sunflower seeds, etc.), the cutting table has different shapes, weights, and types, and also has very different power absorptions. The power absorption range can vary from a simple pick-up that absorbs a few tens of kilowatts (20 - 30 kW) to a multi-row corn cutting table that may absorb up to 150 - 180 kW.

[0006] Generally, the cutting table has cutting members that sometimes must have a specific speed defined according to the condition of the material, and the cutting table has a conveying system to transport the material towards the feed channel of the combine harvester, and the speed of the conveying system depends on the amount of the harvested material.

[0007] In most combine harvesters, power is transmitted to the cutting table via various belt drives that start at a coupling and end at the cutting table. These belt drives can be engaged and disengaged with a belt tensioner or a hydraulic and / or electromagnetic clutch.

[0008] The latest machines have shaft drives that are more reliable than belt drives and thus allow for greater power transmission and require less maintenance.

[0009] After cutting, the material is conveyed towards the threshing system via a feed channel. Usually, to simplify the drive, the feed channel has a fixed transmission ratio with respect to the mechanical part that drives the cutting table. However, some manufacturers have tried to make it possible to vary the speed of the feed channel independently of the cutting table in order to optimize the flow of the material and reduce inefficiencies.

[0010] The threshing system is formed by one or more rotating drums that push the material against a suitably shaped screen by centrifugal force. The plants scrape against the outer screen, causing the grains to separate from the rest of the plant by threshing. In this step, it is important to keep the grains intact in order to obtain a high-quality product, and at the same time, it is important to minimize losses, i.e., to ensure that all the grains are harvested and not left in the field. To achieve this, it must be possible to vary the speed of the drum appropriately, which will depend on the type of material being harvested, the amount of material being processed, and the condition of the material at the time of harvesting (ripeness, humidity, etc.).

[0011] Some threshing drums need to have the possibility, for example, of varying the speed from 200 revolutions per minute to 1200 revolutions per minute, a value that cannot be achieved with a simple belt transmission. To overcome this limitation, some manufacturers use a two- or three-speed gearbox in combination with the transmission in order to be able to cover the entire required speed range.

[0012] The combine harvester also includes cleaning components that allow the grains to fall to the bottom of the combine harvester while conveying the remaining parts of the plants towards the rear part of the machine to subsequently scatter them on the ground. After reaching the bottom of the combine harvester, the grains are stored in a hopper. The rear part of the combine harvester is provided with components for chopping the plant residues and scattering them evenly on the ground when it is not necessary to harvest the plant residues. All the cleaning components are driven by a mechanical drive (which is almost always belt-driven) that usually has a fixed transmission ratio with respect to the internal combustion engine. The chopping components are likewise driven via a belt drive. In contrast, the components for scattering the material are driven mechanically or hydraulically. In more complex machines, a hydraulic solution is used because it allows the speed of the components to be varied and the material to be distributed more evenly on the ground, facilitating subsequent tillage operations.

[0013] The grains are usually unloaded when the hopper is full, and the unloading can be carried out at one side of the field when the combine harvester is not harvesting, or directly on the field when the combine harvester is harvesting.

[0014] The common goal of all combine harvesters is to try to obtain a high-quality product by optimizing the performance of the machine. Considering the complexity of the combine harvester, its different functions, and the components involved, completely different situations may be encountered, which depend on the type of material, the condition of the material, and the condition of the field.

[0015] Obviously, if the combine harvester is not properly managed, it may frequently become blocked or slow down. Sometimes, blockages, especially in the threshing cylinder, can cause the internal combustion engine to stop.

[0016] Therefore, it is important to vary the speeds of four main components, namely: the forward movement section, the cutting table, the feed channel from the cutting table to the threshing cylinder, and the threshing cylinder. The aim is to obtain a constant flow of material, as this can improve the quality of the product, maximize the amount of material being processed, and reduce consumption.

[0017] Despite the increasing complexity of control systems, combine harvesters still frequently exhibit unpredictable and extremely fast torque and power peaks.

[0018] Hybrid combine harvesters have recently been proposed, in which an internal combustion engine is combined with a reversible electric motor that is adapted to operate alternately as a motor and a generator. The control system manages the electric motor so as to: convert excess mechanical power generated by the internal combustion engine into electric power, which is stored in a battery; and use the power from the battery to cover additional power requirements relative to the power transmitted by the internal combustion engine. This type of combine harvester is described in EP2778003. In this combine harvester, the internal combustion engine is associated with a gear train that connects the reversible electric motor to the internal combustion engine and also transmits motion to a control shaft that drives the wheels of the combine harvester and / or its functional units. The electric motor alternately: operates as an electric motor powered by the battery to supply electric power to the control shaft, which is added to the power generated by the internal combustion engine; or operates as a generator rotated by the internal combustion engine to convert the mechanical power generated by the internal combustion engine into electric power, which is stored in the battery.

[0019] Another combine harvester is described in EP3257353, which has the same structure as the combine harvester described in EP2778003. Also, in this case, a reversible electric machine is connected to the output shaft of the internal combustion engine and operates alternately as a motor or a generator. The electric machine is controlled so as to keep the running speed of the internal combustion engine constant.

[0020] These hybrid combine harvesters are not entirely satisfactory in terms of managing the variations in the loads of the various functional units of the combine harvester during operation. In particular, these hybrid combine harvesters are not able to optimize the operation of the different functional units of the same combine harvester.

[0021] US2022 / 0304240 describes a hybrid combine harvester that includes an internal combustion engine and an electric machine composed of a motor-generator. The gear block includes a first input connected to the internal combustion engine and a second input connected to the motor-generator. The gear block further includes an output connected to the threshing cylinder. Suitable clutches allow the internal combustion engine to be disengaged from the gearbox and allow the output of the gearbox to be disengaged from the threshing cylinder. Depending on the load applied to the threshing cylinder, the single electric machine selectively operates as a motor or a generator. If the power supplied by the internal combustion engine is sufficient, the threshing cylinder rotates only by the internal combustion engine. If the power of the internal combustion engine is insufficient, the electric machine operates in motor mode and uses the energy stored in the battery storage system to supply additional power. If the power supplied by the internal combustion engine is greater than the power transmitted to the threshing cylinder, a part of the mechanical power generated by the internal combustion engine is transmitted to the electric machine. In this case, the electric machine operates in motor mode and charges the storage battery.

[0022] From the perspective of consumption and size, this prior art combine harvester fails to optimize the internal combustion engine.

[0023] Therefore, it would be advantageous to produce a hybrid combine harvester that can improve the management of the power flow inside the combine harvester in order to obtain various advantages, including, for example, reduced consumption and an extended service life of the combine harvester and / or its components. Summary of the Invention

[0024] The operation of a combine harvester is characterized by a very high demand for continuous power (from 200 kW for the smallest machines to 450 - 500 kW for the largest ones). Then, the work is concentrated in a few weeks of the year, and during these weeks, the work is carried out almost continuously, with only very few breaks during the day. In addition, the machine usually does not return to the base at the end of the day. For these reasons, a combine harvester is not suitable for using a fully electric drive, as this would require very large batteries, and charging these batteries in the field is very difficult if not impossible. In addition, the weight of a pure electric drive would be much higher than that of the currently internal combustion engine-powered drive, resulting in an increased power level required for travel and having considerable drawbacks when working on soft ground.

[0025] According to the present disclosure, a hybrid drive is provided, which is adapted to combine the power density of an internal combustion engine with the flexibility of an electric drive. Such an agricultural machine provides an internal combustion engine that transmits power to a coupling member, which in turn distributes the power among various components or functional units of the combine harvester. Based on a cost-benefit analysis, the drive to various functional units is purely electric for some functional units (such as the functional unit for forward movement or travel), purely mechanical (by belt drive or the like), or a combination of electric and mechanical through a corresponding combined drive, such as a continuously variable electromechanical drive, which combines the mechanical power of the internal combustion engine with the electric power from a storage battery by using one or more electric motors associated with a continuously variable drive. Such a combined drive is particularly used, for example, to drive a threshing cylinder and / or a cutting table and / or the feed channel between the cutting table and the threshing cylinder.

[0026] Generally, the electric motors provided in the combine harvester disclosed herein can operate as generators and motors according to the operating state. For example, when traveling downhill or braking, the electric motor for travel can operate as a generator and be used to generate electricity. In some functional units, two independent electric motors can be provided, that is, the electric motor includes two electric units, one of which operates specifically or mainly as a motor and the other operates specifically or mainly as a generator.

[0027] In addition, a system for storing electrical energy can be provided for the combine harvester, the system including, for example, batteries, capacitors, or ultracapacitors with fast charge and discharge. The main function of the energy storage system for storing the energy generated by the internal combustion engine and converted into electrical energy is to manage the torque peaks or sudden changes in power of one or another functional unit associated with a drive including at least one electric motor, thereby allowing the control of the operation of the functional unit and additionally optimizing the operation of the internal combustion engine, and thus reducing consumption.

[0028] According to the embodiments disclosed herein, a self-propelled combine harvester including the features of claim 1 is provided. Further features and embodiments are described hereinafter and defined in the dependent claims.

[0029] In particular, according to the present disclosure, the combine harvester includes an internal combustion engine and at least a first electric machine, the at least first electric machine operating mainly as a generator, the generator being mechanically connected directly or indirectly to the internal combustion engine and adapted to convert the mechanical power generated by the internal combustion engine into electric power. In addition, the combine harvester includes a storage system for storing the energy generated by the first electric machine and a first mechanical transmission for connecting the internal combustion engine to a first functional unit. The first mechanical transmission is combined with a second electric machine, the second electric machine being configured to operate at least in motor mode and electrically connected to the storage system to receive electric power from the storage system. The combine harvester further includes a control unit configured to control the second electric machine according to the speed of the first functional unit or the power absorbed by the first functional unit, or the load applied to the first functional unit. Generally, the control of the second electric machine is performed according to at least one operating parameter of the functional unit. The first mechanical transmission includes a first continuously variable transmission, the first continuously variable transmission further including: a first input mechanically connected to the internal combustion engine, a second input mechanically connected to the second electric machine, and an output connected to the first functional unit.

[0030] Generally, the control unit may be connected to a speed sensor, the speed sensor being capable of measuring the speeds of two of the three shafts of the continuously variable transmission, the two shafts being, for example, the input shaft connected to the second electric machine and the output shaft connecting the continuously variable transmission to the functional unit. The characteristics of the continuously variable transmission are known, and the speed of the third shaft can be obtained from the two detected speed values.

[0031] In some embodiments, the control unit may be connected to at least the second electric machine to detect the supply current and voltage. Based on these two data, the power transmitted by the second electric machine to the first functional unit can be obtained.

[0032] Generally, the work performed by the first functional unit absorbs power from the internal combustion engine and, if necessary, from the second electric machine. Based on the speed and / or current and voltage values mentioned above, the control unit can control the operation of the first functional unit by ensuring that a part of the mechanical power is transmitted to the first functional unit by one or more electric machines and a part of the mechanical power is transmitted by the internal combustion engine. The combination of the two powers is obtained via a continuously variable transmission. Thus, it will be more clear according to the exemplary embodiments described below that the power peak transmitted from the internal combustion engine to the functional unit can be reduced and the internal combustion engine can be kept near the optimal operating point with maximum efficiency, thereby reducing consumption.

[0033] In fact, due to the action of the continuously variable transmission and the presence of at least two electric machines combined with the internal combustion engine, the functional unit can maintain a desired rotational speed by absorbing more or less power according to the load on the functional unit, where the internal combustion engine is used to supply the basic power (basic load), and the electric machine combined with the storage system is used to absorb the excess power generated by the internal combustion engine, or to transmit power to supplement the power transmitted by the internal combustion engine, so as to optimize the operation of the functional unit and minimize consumption.

[0034] Preferably, the second electric machine is adapted to operate in motor mode and generator mode and may include a single electric unit or more than one electric unit, where an electric unit refers to a component including a stator and a rotor.

[0035] Therefore, generally, in this document, an "electric machine" refers to a single electric unit including a rotor and a stator, or multiple electric units each including a rotor and a stator. In the second case, in possible embodiments, two or more electric units can be configured to operate alternately as a motor or a generator. In other embodiments, one or more electric units can be adapted to operate specifically or mainly as a generator, and one or more electric units can be adapted to operate specifically or mainly as a motor. Therefore, the term "electric machine" is not limited to a single set including a rotor and a stator.

[0036] The first functional unit may include a threshing drum or rotor, a header, a feed channel between the header and the threshing drum, or a combination thereof.

[0037] One, two or more functional units may be mechanically connected to the internal combustion engine via a coupling, which may include a gear train with an input shaft and multiple output shafts, the input shaft being drivingly coupled to the shaft of the internal combustion engine, one of the output shafts being connectable to the first electric machine and one or more other output shafts being configured to transmit mechanical power from the shaft of the internal combustion engine to one or more functional units.

[0038] In other embodiments, the first electric machine may not be directly connected to the coupling, but rather to a mechanical transmission between the internal combustion engine and the functional unit, for example to the shaft of a continuously variable transmission that connects the internal combustion engine or the coupling to the functional unit. In other embodiments, the first electric machine may include a first electric unit directly connected to the output of the coupling, and a second electric unit connected to the internal combustion engine via a continuously variable mechanical transmission, the continuously variable mechanical transmission being positioned between the internal combustion engine and the functional unit.

[0039] In some embodiments, the continuously variable transmission may include a third input connected to an electric unit belonging to the first electric machine. The third input may include a shaft that is coupled both to the electric unit and to the internal combustion engine, as will be described in detail below. In this case, the continuously variable transmission is effectively connected to two electric units, the two electric units may each include a rotor / stator pair, and both electric units are capable of operating as a motor and a generator, or one operates specifically or mainly as a generator and the other operates specifically or mainly as an electric motor. This configuration may be combined with a coupling whose output is connected to another electric machine that operates mainly as a generator, in which case the other electric machine constitutes the first electric machine (a part of the first electric machine). Alternatively, the first electric machine and the second electric machine are composed of electric units directly connected to the input shaft of the continuously variable transmission.

[0040] Generally, since the energy system of the combine harvester includes at least two electric machines, one operating as a generator (which may also or only operate as a generator) and the other operating as an electric motor (which may also or only operate as an electric motor), the size of the storage system can be significantly reduced because a portion of the available mechanical power is almost continuously converted into electrical power, which charges the storage system.

[0041] Thus, for example, a storage system equipped with supercapacitors can be used, the supercapacitors having a limited storage capacity but a very fast response time. Thus, they can switch from the charging mode to the discharging mode in a very short time and can also deliver a very high electrical power even in a short time. This is particularly useful for reducing the absorption peak of the mechanical power from the internal combustion engine and has the following other advantages.

[0042] Using a continuously variable transmission having a first input mechanically connected to the internal combustion engine and a second input connected to an electric machine adapted to operate as a motor, the speed of the output shaft of the continuously variable transmission can be changed independently of the speed of the internal combustion engine. To maximize efficiency, the speed of the internal combustion engine can be maintained near an optimum value of rotational speed, while the rotational speed of the functional unit can vary as needed or can vary temporarily due to oscillations of the applied load, without affecting the operation of the internal combustion engine or with a much smaller impact on the rotational speed of the internal combustion engine than occurs in prior art systems.

[0043] In a particularly advantageous embodiment, the first functional unit includes the threshing drum and can be connected to the internal combustion engine via a coupling and decoupling device (such as a hydraulic and / or electromagnetic clutch). The transmission between the internal combustion engine and the threshing drum can advantageously be coupled to two electric units, each of which can operate both as a motor and as a generator, or one operates mainly as a motor and the other mainly as a generator, and the two electric units together form the electric machine in the above sense. In addition, one or more inverters are provided which manage the two electric units and the energy storage system simultaneously.

[0044] With the structure described herein, a reduction in the size of the internal combustion engine used can be achieved. The power required for operating peaks is in fact managed by the electric subsystem, which uses the energy stored in the storage system (in the form of electrical energy, chemical energy or other energy). The stored energy is always generated by the internal combustion engine, but is generated at times when the maximum power of the internal combustion engine is not required. Since the internal combustion engine operates at a more constant rotational speed and does not have to suddenly change its operating point, fuel consumption is also reduced. In fact, these sudden changes are managed by the electric subsystem. More precisely, the control unit can manage the electric machine according to the speed of the threshing drum or other functional unit, where the speed of the threshing drum is ensured to be kept near the desired value by changing the electric power flow to and / or from one or more electric machines (motors and generators) associated with the mechanical transmission, which connects the functional unit to the internal combustion engine.

[0045] Specifically referring to the threshing drum, if its speed tends to decrease compared to the desired rotational speed, the control unit ensures that one of the electric units connected to the mechanical transmission (which connects the internal combustion engine to the threshing drum) is supplied with more electric power from the storage system, so as to return the rotational speed of the threshing drum to near the required speed. Conversely, if the speed of the threshing drum tends to increase beyond the required value, the control unit ensures that the other motor associated with the mechanical transmission operates in generator mode, so as to convert mechanical power into electric power, and then the electric power accumulates in the storage system as electrical energy (for example, in the case of a capacitor or a supercapacitor) or in another form of energy (for example, in the form of chemical energy (accumulator battery)).

[0046] The control can also be implemented based on the power during operation and thus based on the load on the threshing drum. For this purpose, it may be useful for the control unit of the combine harvester to receive input data sufficient to determine the power absorbed by the threshing drum and to change the power transmitted by the second motor and the internal combustion engine to the threshing drum. These data can relate to the rotational speed of the output shaft of the continuously variable transmission (and thus the rotational speed of the threshing drum), the rotational speed of the input shaft of the continuously variable transmission connected to the second motor, and the power transmitted by the second motor, which can be determined based on the current and voltage of the second motor. The speeds of the input shaft and the output shaft of the continuously variable transmission are known. Based on considerations of force balance, the rotational speed of the second input shaft can be obtained and thus the power transmitted by the internal combustion engine to the threshing drum can be obtained.

[0047] In this configuration, the control unit can act on the operation of the mechanical power generation devices (internal combustion engine and second motor) so as to cover the load absorbed by the threshing drum by appropriately changing the power transmitted by the power generation devices (that is, so as to supply the total power required to operate the threshing drum at the required speed). Since it is generally advantageous to operate the internal combustion engine at a constant speed, it is generally advantageous to make the change in the mechanical power transmitted by the second motor correspond to the fluctuations in the power absorbed by the threshing drum. If the load on the threshing drum increases (tending to reduce its rotational speed), the power transmitted by the second motor increases correspondingly. The power transmitted by the second motor is generated by absorbing the energy stored in the storage system. Conversely, if the power absorbed by the threshing drum decreases (tending to increase its rotational speed), the power transmitted by the second motor decreases.

[0048] The first motor can be kept rotating by the internal combustion engine to ensure the charging of the storage system.

[0049] The above description of the threshing drum and its control can (alternatively) be implemented on different functional units, such as on the header or on the feed channel between the header and the threshing drum, or in combination thereof.

[0050] Although in an advantageous embodiment, two electric units (one operating mainly as a generator and the other mainly as an electric motor) are associated with the mechanical transmission between the internal combustion engine and the threshing drum, it is also possible to use a single reversible motor, i.e., a single reversible motor consisting of a single electric unit including a stator and a rotor, which operates alternately in motor mode and generator mode. Alternatively, the motor connected to the transmission between the internal combustion engine and the threshing drum can include a single unit and operate mainly or exclusively as an electric motor. In this case, the function of the generator can be assumed by a motor connected to the internal combustion engine at different points, rather than by the transmission between the internal combustion engine and the threshing drum. For example, the function of the generator can be performed by a motor connected to the shaft of the coupling, which is different from the shaft to which the mechanical transmission is connected to the threshing drum.

[0051] Compared to traditional solutions, such as those of the type with hydraulic transmission, a combine harvester having the configuration disclosed herein allows for a reduction in fuel consumption. In fact, electric components have higher efficiency compared to equivalent hydraulic systems for managing continuously variable transmissions.

[0052] The structure having a generator, a motor (or a generator / motor) and a storage system in combination with the internal combustion engine also allows for a reduction in starting peaks, which are usually very severe, especially in the case of a blockage in the threshing drum. In fact, the threshing drum can be started in pure electric mode before engaging the mechanical transmission.

[0053] The reverse function of the threshing drum can also be implemented to eliminate any blockage thereof, without the need to adopt a special mechanism for blocking the internal gears of the mechanical transmission. This is generally not possible in a combine harvester in which the mechanical transmission includes hydraulic components instead of electric components. In the system proposed herein, the generator can act as a brake and / or cause the part normally connected to the mechanical transmission to rotate in the opposite direction.

[0054] According to some embodiments, a hybrid drive implemented via an internal combustion engine and an electric motor (the hybrid drive using a continuously variable mechanical transmission that combines two power sources, an internal combustion engine and an electrical energy storage system) can be provided for the header instead of for the threshing drum, or can be provided for both the header and the threshing drum via two independent continuously variable transmissions, each of the two independent continuously variable transmissions being equipped with two corresponding input shafts for the power generated by the internal combustion engine and the power generated (or absorbed) by a corresponding second electric motor. By applying the continuously variable transmission to the header, advantages similar to those described above regarding the hybridization of the threshing drum are obtained. The above-described structural and functional features can be used in whole or in part in combination with the header.

[0055] In addition, in certain cases, the speeds of the cutting and harvesting members of the header can be optimized according to the forward travel speed of the combine harvester.

[0056] Control can be performed in a manner similar to that illustrated with respect to the threshing drum: the control unit can control the electrical power flow to and from one or more electric motors combined with the mechanical transmission according to the speed of the header, and the aim is to keep the speed within a suitable range near the desired speed, which can be modified during operation if required.

[0057] In this case, two electric units can also be provided, one operating mainly as a motor and the other mainly as a generator. In other embodiments, as described below with reference to the drawings, a single unit or a reversible electric motor is provided that operates alternately and selectively in motor mode and generator mode.

[0058] According to the embodiments described herein, in combination with or as an alternative to one or the other of the hybrid drive systems for the threshing drum and the header, a hybrid system is provided to drive the feed channel between the header and the threshing drum.

[0059] Similar to the drive of the threshing cylinder and / or the header, when using a hybrid power system to drive the feed channel, a mechanical transmission can be provided that receives motion from the internal combustion engine and combines the mechanical power generated by the internal combustion engine with the mechanical power generated by a reversible electric motor powered by the storage system. If the power required by the feed channel is less than the power transmitted by the internal combustion engine, the storage system can absorb the excess power and charge the storage system. Alternatively, the electric motor connected to the feed channel via the continuously variable transmission can operate mainly or exclusively as an electric motor, and any excess mechanical power is absorbed by the first electric motor, which exclusively or mainly performs the generator function, and the first electric motor can be directly connected to the internal combustion engine through the coupling.

[0060] Preferably, the mechanical transmission of the feed channel is combined with a single electric motor that alternately operates as a motor or a generator, but (like the threshing cylinder) two independent electric units can also be used, which mainly operate as a generator and mainly operate as a motor, respectively.

[0061] Similar to that described above for the threshing cylinder and the header, the control unit can control the electric power flow to keep the speed of the feed channel near the desired value, where if the speed of the feed channel tends to decrease, more electric power is transmitted, or if the feed channel tends to accelerate beyond the desired value, mechanical power is converted into electric power to charge the storage system through the electric power.

[0062] For example, using a hybrid drive for the feed channel allows the following advantages to be obtained: simplifying the drive system at the mechanical transmission level and avoiding the engagement and disengagement of the clutch; and optimizing the feed speed according to the material flow, so as to supply only the required amount of energy, thereby reducing consumption.

[0063] In some embodiments, the combine harvester can have a fully electric system for forward movement on the ground, i.e., for traveling. For this purpose, one or more electric motors can be provided, for example, one electric motor for each drive wheel, and the electric energy directly generated by the generator driven by the internal combustion engine and / or the energy transmitted by the storage system supply power to the electric motor.

[0064] Compared with the version using hydrostatic drive, the electric drive allows fuel consumption to be reduced because the efficiency of the electric drive is much higher than that of an equivalent hydraulic drive system. In addition, in the case of braking, by appropriately using the electric motor in generator mode to accumulate energy in the storage system, consumption can be further reduced.

[0065] The cooling system of the internal combustion engine can also be improved by using an electric motor to drive the cooling fan, which generally consists of a radiator and a fan with several parts. In this way, the speed of the fan can be optimized according to the operating temperature, thus reducing consumption.

[0066] Once the combine harvester is equipped with one or more motors operating in generator mode, small electric motors can also be used to drive other components with lower power absorption.

[0067] Generally, the combine harvester includes one or more inverters to convert the electric power generated by a single generator or a generator / motor and enable it to be stored in the storage system, and to transfer the electric power from the storage system to the electric motors associated with individual functional units.

[0068] Advantageously, during field operations, the control unit of the combine harvester manages the different components and functional units (including the traveling components) of the combine harvester, and manages the power flow between each motor / generator and the storage system through the inverter.

[0069] The control unit can act on each individual component it controls, aiming to keep the power contribution mechanically transmitted by the internal combustion engine to each component as constant as possible. This can be achieved by acting on the electric components to manage variations and peaks and by appropriately utilizing the storage system.

[0070] If one of the functional units experiences a severe overload that cannot be managed solely by the storage system, then the control unit can act by changing (reducing) the power transmitted to other functional units in order to keep the speed and power transmitted by the internal combustion engine as constant as possible.

[0071] The values of the voltage and current transmitted to the motor / generator are known, and the operating states of different components and functional units can be accurately and instantaneously read. This enables the control unit to manage and optimize the work, and also enables it to act quickly in case of overload, thus preventing overload. In this way, the possibility of jamming is reduced, and the downtime required to clear the jam is also reduced. In some embodiments, the goal may be to operate the internal combustion engine in a maximum efficiency state, avoiding using the internal combustion engine at maximum power, in order to maximize its performance and reduce its consumption. This strategy allows the use of motors with a lower maximum power than the motors currently used, thus reducing costs and weight.

[0072] By using the internal combustion engine with maximum efficiency, the maintenance cost is reduced.

[0073] According to another aspect, there is provided a method for managing a combine harvester, the combine harvester comprising: an internal combustion engine; at least a first electric machine, the at least first electric machine being mechanically connected to the internal combustion engine and adapted to mainly convert the mechanical power generated by the internal combustion engine into electric power; an energy storage system for storing the energy generated by the first electric machine; a first mechanical transmission for connecting the internal combustion engine to a first functional unit; wherein the first mechanical transmission is combined with a second electric machine, the second electric machine being configured to operate at least in motor mode and electrically connected to the storage system to receive electric power from the storage system; and wherein the first mechanical transmission comprises a continuously variable transmission, the continuously variable transmission comprising: a first input mechanically connected to the internal combustion engine, a second input mechanically connected to the second electric machine, and an output connected to the first functional unit; a control unit configured to control the second electric machine according to the speed of the first functional unit or the power absorbed by the first functional unit, and, if necessary, control the first electric machine.

[0074] The method comprises the steps of: rotating the first electric machine by means of the internal combustion engine and generating electric power; feeding the electric power to the storage system; detecting, via the control unit, a change in the operating parameters of the first functional unit; and in response to the change in the operating parameters of the first functional unit, changing the power transmitted by the first electric machine and the second electric machine to the functional unit via the first mechanical transmission, using, if necessary, the energy stored in the storage system.

[0075] The operating parameters of the functional unit may include the power absorbed by the functional unit or the speed of the functional unit, or both.

[0076] Advantageously, the functional unit may include a threshing drum. In some embodiments, the functional unit may include a cutting table or a feed channel between the cutting table and the threshing drum, or a combination thereof. In the case of a combination of more than one functional unit, each functional unit may include a continuously variable transmission and a dedicated electric machine. The control unit may control each electric machine of each functional unit by a method similar to the method described for the management of the threshing drum. Description of the Drawings

[0077] The present invention will be better understood from the following description and drawings, which illustrate non-limiting examples of embodiments of the present invention. More specifically, in the drawings:

[0078] Figure 1 A side view schematic of a combine harvester is shown;

[0079] Figure 2 Figure showing a functional unit and associated electric and mechanical transmissions and a system for storing and managing power flow;

[0080] Figure 3 Figure showing the mechanical transmission and associated electric components for driving the threshing drum;

[0081] Figure 4 Figure showing the mechanical transmission and associated electric components for driving the feed channel and the header;

[0082] Figure 5 Figure showing a time graph of the power absorbed by the threshing drum and the power transmitted by the internal combustion engine and the electric system; and

[0083] Figure 6 Figure showing a histogram exemplifying the distribution of the power transmitted by the internal combustion engine to the threshing drum. Detailed description

[0084] In the following description, embodiments with an electric or hybrid-electric power supply provided with all the main functional units (i.e., header, feed channel, threshing drum, forward movement (travel), cooling of the internal combustion engine) will be referred to. However, it must be understood that in some embodiments, a hybrid or electric drive system may be provided only for one or some of the functional units.

[0085] Preferably, at least the threshing drum and the header are equipped with a transmission that combines mechanical power directly from the internal combustion engine with electric power supplied by or transmitted towards a storage system. Advantageously, the transmission includes a continuously variable transmission.

[0086] Now referring to the drawings, Figure 1 A side view of a combine harvester 1 equipped with a header 3 and wheels 5 is schematically shown, where at least some of the wheels are drive wheels. The reference numeral 7 denotes a grain unloading system. Inside, the combine harvester 1 is provided with various functional units, which are schematically shown in Figure 2 the figures.

[0087] In Figure 2 the figure, the reference numeral 11 denotes an internal combustion engine, which is mechanically connected to the threshing drum 13, the header 3, and the feed channel 15 in such a way that the feed channel conveys the product cut and harvested by the header 3 towards the threshing drum 13.

[0088] Reference numeral 17 denotes a mechanical transmission device, also referred to hereinafter as a "coupling member", which connects the output shaft of the internal combustion engine 11 to the first electric machine 19 (also referred to hereinafter as the generator set 19, or simply the generator set 19) and other components described hereinafter. In the illustrated embodiment, the generator set 19 includes a first generator 19A and a second generator 19B. In other embodiments not shown, the generator set 19 may include a single generator, or more than two generators. In other embodiments, the generator set 19 may be positioned differently, as described hereinafter.

[0089] The generator set 19 is electrically connected to a storage system 21, which may include, for example, a battery or other storage medium, such as a supercapacitor or the like. Given the fast discharge of the supercapacitor, i.e., its ability to deliver a high current in a short time, it is particularly advantageous to use a supercapacitor as the storage medium.

[0090] The electrical connection between the generator set 19 and the storage system 21 includes the arrangement of an inverter 23. Schematically, in Figure 1 the arrangement of the inverter 23 includes n inverters denoted by 23.1, 23.2, ……, 23.n.

[0091] Advantageously, the inverters 23.1, ……, 23.n, the storage system 21, and the generator set 19 are functionally connected to a control or monitoring unit 25.

[0092] The coupling member 17 may be connected via a clutch 29 to one or a series of pulleys 27, which transmit motion to one or more functional units (not shown). The clutch 29 (such as an electromagnetic clutch) may be functionally connected to the control unit 25, which controls the engagement and disengagement of the clutch 29 according to the operating requirements of the combine harvester.

[0093] For example, the pulley 27 may transmit motion to one or more of the following components:

[0094] - cleaning components, such as sieves and blowers, which separate the grains from the remaining parts of the plant;

[0095] - components for collecting the grains in a hopper.

[0096] Through subsequent branches, the motion may also be transmitted, for example, through a suitable engagement / disengagement system to discharge components, such as:

[0097] - a straw chopping component;

[0098] - a straw spreading component;

[0099] - a grain unloading component.

[0100] In fact, the coupling 17 may include a cascaded gearbox having an input connected to the internal combustion engine 11 and a plurality of output shafts, one of the output shafts being connected to the one or a series of pulleys 27.

[0101] Via one of the output shafts of the coupling 17, the movement of the internal combustion engine 11 can be transmitted to a mechanical connection 31 that transfers power from the output of the internal combustion engine 11 to the threshing drum 13. The mechanical connection 31 may include a clutch 33, such as an electromagnetic clutch, which is functionally connected to the control unit 25 and can be engaged or disengaged to transmit or not transmit the mechanical power generated by the internal combustion engine 11 to the threshing drum 13 via the coupling 17.

[0102] The mechanical connection 31 may include a shaft schematically designated by reference numeral 35, such as a drive shaft, which transfers movement to a first input 37.1 of a mechanical transmission 37 (in particular a continuously variable transmission). The figure Figure 3 illustrates possible configurations of the continuously variable mechanical transmission 37.

[0103] The continuously variable mechanical transmission 37 is combined with a second electric machine 39. In the illustrated embodiment, the second electric machine 39 includes a first electric unit 39.1 and a second electric unit 39.2. Both the first and second electric units 39.1 and 39.2 may be reversible electric machines, adapted to operate alternately as a motor and a generator, and typically include a respective rotor and a respective stator. In other embodiments, the two electric units 39.1 and 39.2 may be controlled such that one operates exclusively in motor mode and the other operates exclusively in generator mode. The two electric units 39.1 and 39.2 are functionally connected to the control unit 25 (see Figure 2 ). In some embodiments, the second electric machine 39 may also be controlled such that it operates only in motor mode.

[0104] More than one first electric unit 39.1 may also be used in parallel and more than one second electric unit 39.2 may also be used in parallel.

[0105] In some embodiments, the generator 19 may be omitted and its function may be performed by an electric machine mechanically connected to the mechanical connection 31. For example, the first electric unit 39.1 may constitute a generator or operate mainly as a generator and perform the function of the first electric machine or generator 19. The second electric unit 39.2 may constitute an electric machine that serves the threshing drum 13 and is mainly used in motor mode to supply mechanical power to the threshing drum 13 via the continuously variable transmission 37.

[0106] In Figure 3In the embodiment illustrated in the figure, the continuously variable mechanical transmission 37 includes a first mechanical power input 37.1 connected to the input shaft 35 (see Figure 3 ), and a second input. The second input actually includes a first shaft 37.2 connected to the first electric unit 39.1 and a second shaft 37.3 connected to the second electric unit 39.2. The continuously variable mechanical transmission 37 further includes an output 37.4 connected to the functional unit represented by the threshing drum 13.

[0107] For example, the continuously variable mechanical transmission 37 includes a housing 37.5 in which a planetary gear device 37.6 and an output bevel gear 37.7 are accommodated.

[0108] In fact, the continuously variable transmission 37 can receive the power directly generated by the internal combustion engine 11 and transmitted from the internal combustion engine 11 to the continuously variable transmission 37 through the coupling 17 and the transmission shaft 35. The mechanical power supplied through the input 37.1 can be combined with the mechanical power generated by one and / or the other of the two electric units 39.1 and 39.2 through the planetary gear device 37.6 to operate (via the output 37.4) the threshing drum 13. In some embodiments, one of the two electric units 39.1, 39.2 can be omitted.

[0109] For example, the rotational speed of the threshing drum 13 can be detected by a specific sensor. The reference numeral 14 schematically represents the sensor, which can directly or indirectly detect the speed of the threshing drum 13, for example, by detecting the speed of the output shaft 37.4. The sensor 14 is functionally connected to the control unit 25.

[0110] In some embodiments, the sensor 14 can also be adapted to detect the speed of at least one of the input shafts. By measuring two of the three speeds of the input shaft / output shaft of the continuously variable transmission 37, the rotational speed of the third input shaft or output shaft can be calculated.

[0111] The power transmitted (or absorbed) by the electric machine 39 is known, for example, calculated based on the power supply voltage and the current absorbed (or generated) by the electric machine 39. The control unit 25 is able to know the power flow from and / or towards each group connected to the continuously variable transmission 37, that is: the power absorbed by the threshing drum 13, the power transmitted from the internal combustion engine 11 to the threshing drum, and the power transmitted by the electric machine 39 (or the power absorbed by the electric machine and fed to the storage system).

[0112] Thus, the control unit 25 can change the power flow to optimize the operation of the internal combustion engine 11, thereby maintaining the threshing cylinder in the desired operating state. In short (further details of the embodiment will be described below), the control unit 25 can ensure that the electric motor 39 compensates for the threshing cylinder's need for greater temporary power requirements by increasing the power transmitted by the electric motor 39, for which purpose the electric motor absorbs the energy stored in the storage system. The control unit 25 can also advantageously control the generators 19 (19A, 19B) based on the power generated by the internal combustion engine 11 and the power absorbed by the functional units of the combine harvester, so that the excess mechanical power generated by the internal combustion engine is converted into electrical power by the generator 19 to charge the storage system 21.

[0113] In other embodiments, instead of using a speed sensor, the rotational speed of the threshing cylinder can be calculated based on the speeds detected on the electric units 39.1 and 39.2, so that the control unit 25 can change the power flow through the electric units 39.1 and 39.2 (which together constitute the electric motor 39) and maintain the rotational speed of the threshing cylinder 13 near the set speed. The desired speed of the threshing cylinder can be constant or can be changed by the operator as needed, particularly for example depending on the type of product being processed and its state.

[0114] For example, when the speed required by the threshing cylinder 13 is greater than the mechanical transmission ratio of the planetary gear unit of the mechanical transmission 37, the electric unit 39.1 can operate mainly as a generator and convert mechanical power into electrical power, and the electrical power supplies the electric unit 39.2 through the arrangement of the inverter 23. In this case, the electric unit 39.2 operates mainly as an electric motor. In this case, when the rotational speed of the threshing cylinder 13 tends to increase beyond the set value (relative to the lower power required by the cylinder during operation), a part of the electrical energy generated by the electric unit 39.1, which actually acts as a brake, supplies the storage system 21 through the arrangement of the inverter 23, thereby reducing the power available to the electric unit 39.2 and the threshing cylinder 13, which results in a speed reduction. Conversely, when the threshing cylinder tends to reduce its speed (relative to the greater power required by the threshing cylinder during operation), the electric unit 39.2 can convert the electrical energy collected from the storage system 21 through the arrangement of the inverter 23 and in this way supply the additional power required to maintain a constant speed to the threshing cylinder 13. The reference signs A and B denote the electrical connections between the electric units 39.1 and 39.2 and the arrangement of the inverter 23.

[0115] In this way, the continuously variable transmission 37 allows the power transmitted to the threshing cylinder 13 to be increased or decreased, thereby maintaining its operating speed within a tolerance range near the desired value and at least within certain operating limits, without changing the rotational speed of the internal combustion engine 11.

[0116] The control system acts by using a signal representing the rotational speed of the threshing cylinder, which signal constitutes the controlled parameter and can be provided by sensor 14. Since the motors 39.1 and 39.2 are controlled according to the detected rotational speed of the threshing cylinder 13, the rotational speed of the internal combustion engine 11 can be kept substantially constant. Thus, the control of the rotational speed of the internal combustion engine 11 can be omitted.

[0117] As described above, in other embodiments, only one of the electric units 39.1 and 39.2 can be provided, which can be controlled to operate in motor mode or generator mode according to the variation of the rotational speed of the threshing cylinder, so as to tend to keep the speed within a tolerance range near the desired rotational speed value.

[0118] Keeping the rotational speed of the internal combustion engine 11 near a predetermined value allows for a reduction in fuel consumption, which corresponds to the maximum efficiency state of the internal combustion engine.

[0119] Furthermore, since in the case of the power absorption peak, the larger power required by the threshing cylinder is supplied by the motor, this allows for a smaller-sized internal combustion engine to be installed on the combine harvester 1 compared to the currently required internal combustion engine. In fact, in the traditional system, the internal combustion engine must be able to supply all the power required for the absorption peak of the threshing cylinder 13, so the size of the internal combustion engine must be oversized compared to the absorption in the normal operating state. Conversely, in the configuration described herein, the power absorption peak supplied by the internal combustion engine is smoothed, because when the control unit detects a reduction in the speed of the threshing cylinder 13 (which indicates that more power must be transmitted), the control unit 25 requests the motor 39 to transmit power to make up for the greater demand. The power peak of the internal combustion engine is limited to the power peak required for the transition phase until the electric system can make up for the increased power demand.

[0120] Using at least two different motors, one of which operates as a motor (at least one of the electric units 39.1, 39.2) and the other operates as a generator (the generator set 19 and / or one of the electric units 39.1, 39.2), allows the storage system 21 to maintain a sufficient power level without increasing the size of the storage system.

[0121] Instead of the speed of the functional unit (which includes the threshing cylinder in this example), the load borne or the power absorbed by the threshing cylinder can be used.

[0122] In some embodiments, the control unit 25 may be connected to the speed sensors 14, which are adapted to detect the speed of at least two of the first input of the continuously variable transmission 37, the second input of the continuously variable transmission 37, and the output of the continuously variable transmission. The control unit 25 may also know the power transmitted by the electric machine 39, for example, the power may be determined based on the supply current and the supply voltage. Considering the principle of force balance acting inside the continuously variable transmission, the power transmitted from the internal combustion engine 11 to the threshing drum 13 can be determined when the foregoing two speeds and the power transmitted by the electric machine 39 are known. The sum of the power supplied by the electric machine 39 and the internal combustion engine 11 to the threshing drum 13 is actually the total power required by the threshing drum, which corresponds to the load applied to the threshing drum.

[0123] For example, when the power absorbed by the threshing drum 13 changes, the control unit 25 may change the power of the electric machine 39 in order to keep the threshing drum 13 in a selected operating state without overloading the internal combustion engine 11 or unduly changing the operating state of the internal combustion engine. In fact, the internal combustion engine 11 will be kept near the operating point that optimizes its efficiency for as long as possible.

[0124] For example, if the control unit 25 detects an increase in the power absorbed by the threshing drum 13 based on the foregoing data, the control unit 25 may change the power transmitted by the electric machine 39 and increase it. This is achieved by using the energy stored in the storage system 21. The electric machine 39 can almost immediately transmit a greater mechanical power to the threshing drum 13 in order to avoid an excessive increase in the power transmitted by the internal combustion engine 11.

[0125] For a better understanding of the method of managing the power flow and the advantages of using the hybrid configuration described herein, reference is made to Figure 5 and Figure 6 。 Figure 5 Time (in seconds) is shown on the abscissa and power and speed are shown on the ordinate. More specifically, curve C1 is the curve of the rotational speed of the threshing drum 13 operated by the internal combustion engine in a conventional threshing machine changing with time. Curve C2 is the curve of the rotational speed of the threshing drum 13 in the combine harvester according to the present disclosure changing with time, wherein the threshing drum 13 is operated by a hybrid system including the internal combustion engine 11 and electric machines 39.1, 39.2. Curve C3 is the curve of the power transmitted by the internal combustion engine changing with time in a prior art combine harvester equipped only with an internal combustion engine. Curve C4 is the curve of the power transmitted by the internal combustion engine changing with time in the combine harvester according to the present disclosure. Curve C5 is the curve of the power level of the storage system 21 changing with time.

[0126] Specifically referring to curve C1, it can be observed that this curve shows a greater speed variation of the threshing cylinder compared to the speed variation of the threshing cylinder 13 in the combine harvester equipped with a hybrid system according to the present disclosure. In other words, since the electric motor 39 and the internal combustion engine 11 are combined via a continuously variable mechanical transmission 37, a more regular rotational speed of the threshing cylinder 13 is obtained with respect to the machines of the prior art.

[0127] This more regular variation trend, which is advantageous in itself, is achieved in the case where the internal combustion engine 11 has a favorable energy behavior. In fact, curve C3 shows that when the rotational speed of the threshing cylinder decreases (curve C1), there is a significant demand for the peak power of the internal combustion engine and thus this peak power is transmitted. For example, it can be noted that a decrease in speed occurs at point C1.1 and, in response, the internal combustion engine outputs a strong power peak C3.1. This fluctuation in the operating state of the internal combustion engine causes it to deviate from the ideal operating point at maximum efficiency.

[0128] When the mechanical power for the rotation of the threshing cylinder 13 is supplied by the combination of the internal combustion engine 11 and the electric motor 39, the curve of the angular velocity (curve C2) and the curve of the power transmitted by the internal combustion engine 11 (curve C4) show a more favorable situation. In fact, the positive and negative peaks of the angular velocity are less pronounced. The power peaks transmitted by the internal combustion engine are also less pronounced. Compared to the situation of the machines of the prior art, the fluctuations in the power transmitted by the internal combustion engine 11 are significantly reduced, which means that the internal combustion engine operates more regularly near the maximum efficiency point and thus consumption is reduced.

[0129] Curve C5 shows that at the power peak in curve C4, the electric motor 39 correspondingly transmits power, resulting in a decrease in the charge of the storage system 21. Substantially, when the control unit 25 detects a decrease in the angular velocity of the threshing cylinder 13, it activates the power transmission system via the electric motor 39, causing the storage system 21 to consume energy. The response time of the system makes it impossible to completely eliminate the fluctuations in the power transmitted by the internal combustion engine 11 (curve C4), but the peaks can be significantly reduced and smoothed.

[0130] In the time range in which the power required by the threshing cylinder 13 decreases (for example, between 220 seconds and 270 seconds), as the threshing cylinder shows a tendency for angular acceleration, the control unit 25 switches the electric motor 39 to the generator mode, thus increasing the mechanical resistance on the shaft of the internal combustion engine 11. Therefore, the internal combustion engine tends to maintain a constant speed (curve C4 is flat and approximately horizontal), and the excess power generated by the internal combustion engine 11 is used to charge the storage system 21. This charging is shown by the upward trend of curve C5 in the time range between 220 seconds and 270 seconds.

[0131] The beneficial effects of the hybrid system described can also be achieved byFigure 6 The data shown in the histogram is highlighted. The (dimensionless) power transmitted by the internal combustion engine is shown on the horizontal axis, and the percentage of use at different powers is shown on the vertical axis. The bar marked W1 represents the power transmitted by the internal combustion engine of a conventional combine harvester. The bar W2 represents the power transmitted by the internal combustion engine 11 in the combine harvester 1 of the present disclosure. The histogram is calculated based on Figure 5 the data shown in. It should be noted that in the case where the internal combustion engine 11 is used in a hybrid configuration, that is, in combination with the electric motor 39 and the continuously variable transmission, the power transmitted by the internal combustion engine 11 is 12 (dimensionless) for approximately 45% of the time, within which the internal combustion engine remains in the maximum efficiency state. Compared with the conventional system (bar W1), in the case of the hybrid system (bar W2), the power transmitted at speeds different from the optimum speed is almost always much smaller, especially when used at speeds higher than the optimum speed, almost dropping to zero. This will allow the use of an internal combustion engine with a lower maximum power to perform the same work.

[0132] From Figure 6 the figures in, it can be seen that the maximum value of the power required by the internal combustion engine 11 in the hybrid system disclosed herein (the dimensionless scale on the abscissa) is always much lower than the maximum power required by the internal combustion engine in a conventional combine harvester. The figure particularly shows that in the case of hybrid drive, the maximum power required by the internal combustion engine 11 is less than 19 (dimensionless value), while in a conventional combine harvester, in some cases, the internal combustion engine needs to transmit a power greater than 26 (dimensionless quantity). Therefore, the hybrid configuration allows the size of the internal combustion engine to be reduced and its efficiency to be optimized.

[0133] In short, the described system tends to keep the speed of the threshing cylinder 13 near the required value by changing the power transmitted by or absorbed by the electric system. In this way, the internal combustion engine 11 automatically remains in a steady state as close as possible to the maximum efficiency state, which matches the rapidity of the power change required by the threshing cylinder 13 and the intervention speed (response time) of the control system of the electric components of the system.

[0134] Although the hybrid system for driving the threshing cylinder 13 has been described above, it must be understood that the same drive and control logic can be used for other functional units, as briefly described below.

[0135] The cutterbar 3 can be driven by a hybrid arrangement similar to the hybrid arrangement described with reference to the drive of the threshing cylinder 13, where, according to the operating state, the mechanical power generated by the internal combustion engine 11 is directly used and the electric power transmitted through the arrangement of the inverter 23 or the electric power input again into the storage system 21 through the arrangement of the inverter 23.

[0136] To this end, another mechanical coupling 41 can be connected to the coupling 17, which transmits power from the output of the internal combustion engine 11 to the header 3 and, as described below, to the feed channel 15. The mechanical coupling 41 can include a clutch 43, such as an electromagnetic clutch, which is functionally connected to the control unit 25 and can be engaged or disengaged to directly transmit or not transmit the mechanical power generated by the internal combustion engine 11 to the header 3 and the feed channel 15.

[0137] The mechanical coupling 41 can include a series of shafts, schematically denoted by 45.1 and 45.2 ( Figure 2 and 4 ), such as drive shafts, which transmit motion to a first input 47.1 of a mechanical transmission 47 (such as a continuously variable transmission). In Figure 4 FIG. illustrating a possible configuration of the continuously variable mechanical transmission 47. The continuously variable mechanical transmission 47 is combined with a single electric machine 49, which can operate in generator mode or motor mode and is functionally connected to the control unit 25.

[0138] In other embodiments, not shown, the continuously variable transmission 47 can include two electric units, as schematically shown for the continuously variable transmission 37.

[0139] In the illustrated embodiment, two electric units 39.1 and 39.2 are associated with the threshing cylinder 13, while a single electric unit is associated with other functional units (such as the header). This is because the threshing cylinder is the component of the combine harvester with the highest rated power absorption. The threshing cylinder does not absorb the highest power for all crops, but the power required for certain crops makes it the component with the highest (installed) rated power. In addition, the threshing cylinder is the component that requires the greatest speed variation: the ratio between the minimum speed and the maximum speed can reach 1:6, while other components require a more limited variation, typically a ratio lower than 1:2.

[0140] In a CVT transmission, the high power required together with the wide speed range requires the use of high power components capable of managing the variation (in this case electric motors or electric units 39.1, 39.2). In this case, it may be more advantageous to have a dedicated electric machine or electric unit as a generator directly powering the electric motor. An alternative is to have a generator with a higher rated power on the coupling.

[0141] Conversely, for other functions of the machine, the reduced speed range allows the use of electric motors or electric units with a lower rated power, and it may be more appropriate to power these electric motors or electric units via a "single" slightly larger generator installed on the coupling.

[0142] The continuously variable mechanical transmission 47 includes a first mechanical power input 47.1 connected to the input shaft 45.2 (see Figure 4 ), and a second input 47.2 connected to the electric unit 49. The continuously variable mechanical transmission 47 further includes an output 47.4 connected to the harvesting platform. The output 47.4 is preferably a dual output to control two transmission shafts 47.8, 47.10.

[0143] Reference numeral 47.6 denotes a planetary gear set accommodated in the housing 47.5 of the continuously variable transmission 47. Motion is transmitted to the planetary gear set 47.6 through a bevel gear 47.12, which is interposed between the planetary gear set and the input 47.1.

[0144] Similar to the planetary gear set 37.6 of the continuously variable transmission 37, the mechanical power input through the shaft 45.2 can be combined with the mechanical power flowing through the electric motor 49 via the planetary gear set 47.6. This electric motor is controlled by the control unit 25 so as to keep the speed of the harvesting platform 3 constant, or at least within tolerances.

[0145] In the illustrated configuration, the electric motor 49 operates as a generator or a motor according to the rotational speed set for the harvesting platform. Power variations that may be caused by torque peaks are managed by extracting power from the storage system 21 when operating in motor mode or supplying power (charging) to the storage system 21 when operating as a generator, thereby keeping the power transmitted by the shaft 45.2 constant in this way, and thus keeping the power contribution that the internal combustion engine 11 needs to provide constant.

[0146] Similar to the threshing cylinder 13, the control unit 25 does not need to control the rotational speed of the internal combustion engine 11.

[0147] In Figure 2 's figure, reference numeral 48 denotes a rotational speed sensor of the harvesting platform, which is functionally connected to the control unit 25. Via the signal from the sensor 48, the control of the electric motor 49 can be carried out with the same logic as described for the reference electric motor 39.

[0148] In the illustrated embodiment, the feed channel 15 is also controlled by a hybrid arrangement, which includes a continuously variable transmission that advantageously includes a planetary gear set. Referring again to Figure 2 and Figure 4 to describe the structure of the transmission for controlling the feed channel 15.

[0149] Shaft 45.1 ( Figure 2 and Figure 4)Transfer the motion to the first input 57.1 of the mechanical transmission 57 (e.g., a continuously variable transmission). In Figure 4 Figure showing a possible configuration of the continuously variable mechanical transmission 57. The continuously variable mechanical transmission 57 is combined with a single electric machine 59, which can operate in generator mode or motor mode and is functionally connected to the control unit 25.

[0150] In other embodiments not shown, the continuously variable transmission 57 may include two electric units, as schematically shown for the continuously variable transmission 37.

[0151] More precisely, the continuously variable transmission 57 includes a first mechanical power input 57.1 connected to the shaft 45.1 via bevel gears 57.12 (see Figure 4 ), and the motion is transmitted to the bevel gears via the input shaft 57.13. The continuously variable mechanical transmission 57 further includes a second input 57.2 connected to the electric machine 59 and dual outputs 57.4A, 57.4B. The output 57.4A controls the feed channel 15, and, if provided, the output 57.4B may control a member for removing stones and other debris, which is schematically denoted by the reference numeral 81 and is known per se.

[0152] The reference numeral 57.6 denotes a planetary gear set accommodated in the housing 57.5 of the continuously variable transmission 57. Similar to the planetary gear set 37.6 of the continuously variable transmission 37, the mechanical power input via the shaft 45.1 can be combined with the mechanical power flowing through the electric machine 59 via the planetary gear set 57.6. The electric machine is controlled by the control unit 25 in order to keep the speed of the feed channel 15 constant, or at least within tolerances.

[0153] In the illustrated configuration, the electric machine 59 operates as a generator or a motor according to the rotational speed set for the feed channel. Power variations that may be caused by torque peaks or by the need to temporarily change the speed of the channel due to an excess of material are managed by extracting power from the storage system 21 when operating in motor mode or by supplying power (charging) to the storage system 21 when operating as a generator, thereby keeping the power transmitted by the shaft 45.2 constant in this way and thus keeping the power contribution that the internal combustion engine 11 needs to provide constant.

[0154] In Figure 2 , the reference numeral 58 denotes a speed sensor that transmits the speed of the feed channel 15 to the control unit 25.

[0155] The electric machine 59 can be controlled in a manner similar to that described with reference to the electric machine 39 for the hybrid drive of the threshing drum 13.

[0156] Similar to the threshing cylinder and the harvesting table, the control unit 25 does not need to control the rotational speed of the internal combustion engine 11.

[0157] Due to changes in the operating state, a possible speed change of one or the other of the functional units may be required. In such a case, it is always the control unit 25 that can act on the above-mentioned electric motor to bring the speed of the corresponding functional unit to the desired value.

[0158] Figure 2 The figure also shows an electric motor 83 associated with the drive wheel 5 and functionally connected to the control unit 25. The electric motor 83 is powered by the arrangement of the inverter 23 and provides power for the forward movement (i.e., traveling) of the combine harvester 1.

[0159] For example, in Figure 2 the illustrated embodiment, the internal combustion engine 11 is associated with a cooling system that may include a radiator 87 and a cooling fan driven by an electric motor 85, which is powered by the arrangement of the inverter 23.

Claims

1. A self-propelled combine harvester, comprising: An internal combustion engine; At least a first electric machine, said at least first electric machine being mechanically connected to said internal combustion engine and adapted to mainly convert the mechanical power generated by said internal combustion engine into electric power; A storage system for storing the energy generated by said first electric machine; A first mechanical transmission that connects said internal combustion engine to a first functional unit; wherein said first mechanical transmission is combined with a second electric machine, said second electric machine being configured to operate at least in motor mode and electrically connected to said storage system to receive electric power from said storage system; A control unit configured to control at least said second electric machine according to at least one operating parameter of said first functional unit; Wherein said first mechanical transmission includes a first continuously variable transmission, said first continuously variable transmission including: a first input mechanically connected to said internal combustion engine, a second input mechanically connected to said second electric machine, and an output connected to said first functional unit.

2. The combine harvester according to claim 1, wherein, Said control unit is configured to also control said first electric machine according to the operating parameters of said first functional unit.

3. The combine harvester according to claim 1 or 2, wherein, Said operating parameters are selected from the group including the following: the speed of said first functional unit; the power absorbed by said first functional unit; combinations thereof.

4. The combine harvester according to one or more of the preceding claims, wherein, Said first functional unit includes at least one of the following: a threshing cylinder; a cutting table; a feed channel between said cutting table and said threshing cylinder; combinations thereof.

5. The combine harvester according to one or more of the preceding claims, wherein, Said control unit is adapted to control said second electric machine so that: In the case where the speed of said first functional unit tends to decrease, or in the case where the power absorbed by said first functional unit tends to increase, power is transmitted to said first functional unit through said second electric machine; And In the case where the speed of said first functional unit tends to increase, or in the case where the power absorbed by said first functional unit tends to decrease, mechanical power is absorbed from said first functional unit and converted into electric power transmitted towards said storage system.

6. The combine harvester according to one or more of the preceding claims, wherein, Said second electric machine includes an electric motor and a generator, said electric motor and generator being respectively connected to a first input shaft of said first input of said first continuously variable transmission and a second input shaft of said first input of said first continuously variable transmission.

7. The combine harvester according to one or more of the preceding claims, wherein: Said combine harvester includes a second mechanical transmission that connects said internal combustion engine to a second functional unit; said second mechanical transmission includes a second continuously variable transmission, said second continuously variable transmission including: a first input mechanically connected to said internal combustion engine, a second input mechanically connected to a third electric machine, and an output connected to said second functional unit; said third electric machine being configured to operate at least in motor mode and electrically connected to said storage system to receive electric power from said storage system; and said control unit is configured to control said third electric machine according to at least one operating parameter of said second functional unit, in particular the speed of said second functional unit, the power absorbed by said second functional unit, or combinations thereof.

8. The combine harvester according to claim 7, wherein, The second functional unit includes a cutting table.

9. The combine harvester according to one or more of the preceding claims, wherein: The combine harvester includes a third mechanical transmission that connects the internal combustion engine to a third functional unit; wherein the third mechanical transmission includes a third continuously variable transmission that includes: a first input mechanically connected to the internal combustion engine, a second input mechanically connected to a fourth electric motor, and an output connected to the third functional unit; the third mechanical transmission is combined with the fourth electric motor, the fourth electric motor is configured to operate at least in motor mode and is electrically connected to the storage system to receive electrical energy from the storage system; and the control unit is configured to control the fourth electric motor based on at least one operating parameter of the third functional unit, in particular the speed of the third functional unit, the power absorbed by the third functional unit, or a combination thereof.

10. The combine harvester according to claim 9, wherein, The third functional unit includes a feed channel between the cutting table and the threshing cylinder.

11. The combine harvester according to one or more of the preceding claims, wherein, Each electric motor is adapted to operate in motor mode or generator mode; and wherein each electric motor includes: An electric unit having a rotor and a stator, the electric unit being configured to alternately operate in motor mode and generator mode; or A first electric unit having a rotor and a stator, the first electric unit being adapted to operate mainly or exclusively in motor mode, and a second electric unit having a rotor and a stator, the second electric unit being adapted to operate mainly or exclusively in generator mode.

12. The combine harvester according to one or more of the preceding claims, wherein, At least one and preferably each continuously variable transmission includes a planetary gear device.

13. A combine harvester according to one or more of the preceding claims, which includes a plurality of drive wheels driven by at least one electric motor connected to the storage system.

14. A combine harvester according to one or more of the preceding claims, which includes a cooling fan for the internal combustion engine, the cooling fan being driven by an electric motor connected to the storage system.

15. A combine harvester according to one or more of the preceding claims, which includes a coupling between the internal combustion engine and each of the mechanical transmissions.

16. The combine harvester according to claim 15, wherein, The first electric motor is mechanically connected to the internal combustion engine via the coupling.

17. The combine harvester according to one or more of the preceding claims, wherein, The control unit is configured to detect: at least the rotational speed of the first functional unit, or the power absorbed by the first functional unit, and the control unit is configured to control at least the second electric motor so as to respond to a change in the power absorbed by the functional unit relative to a preset value by a change in the power transmitted by the second electric motor to the functional unit.

18. A method for managing a combine harvester, the combine harvester comprising: Internal combustion engine; At least a first electric motor, the at least first electric motor being mechanically connected to the internal combustion engine and adapted to convert the mechanical power generated by the internal combustion engine into electrical power; A storage system for storing the energy generated by the first electric machine; a first mechanical transmission connecting the internal combustion engine to a first functional unit; wherein the first mechanical transmission is combined with a second electric machine configured to operate at least in motor mode and electrically connected to the storage system to receive electrical energy from the storage system; and wherein the first mechanical transmission comprises a continuously variable transmission including a first input mechanically connected to the internal combustion engine, a second input mechanically connected to the second electric machine, and an output connected to the first functional unit; a control unit configured to control the second electric machine based on at least one operating parameter of the first functional unit, in particular the speed of the first functional unit, the power absorbed by the first functional unit, or a combination thereof; the method comprising the steps of: Rotating the first electric machine by the internal combustion engine and generating electrical power; Feeding the electrical power to the storage system; Detecting, via the control unit, a change in the at least one operating parameter of the first functional unit; and In response to a change in the operating parameter of the first functional unit, changing the power transmitted by the second electric machine to the first functional unit via the first mechanical transmission.

19. The method according to claim 18, wherein, The first functional unit comprises at least one of the following: a threshing drum, a cutting table, a feed channel between the cutting table and the threshing drum, combinations thereof.

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