Agricultural processing vehicle with hybrid or electric power supply and electric traction

Abstract

A frame (4) having a longitudinal hollow beam (T) a power take-off (PTO) configured to provide the connection and operation of mechanically operated agricultural equipment, an electric power take-off (EPTO) a front reversible electric machine (EM1) mechanically connected to said power take-off (PTO) via a shaft (8) housed in the hollow beam, a hydraulic pump (9) connected in torque transmission to the shaft, preferably to operate a power steering of the vehicle and hydraulic equipment an electric traction motor (EM2) mechanically decoupled from said reversible machine (EM1), fixed to the frame (4) of the vehicle and connected by mechanical transmission means to one or more wheels or tracks (R) of the vehicle, the electric traction motor (EM2) being interposed between the front and rear axles (5) of the frame (4) at least one electric battery unit (B) connected to a first electronic electrical conversion unit (EL1) configured to supply energy to, or receive energy from, said reversible machine (EM1), and to a second electronic electrical conversion unit (EL2) configured to power said electric traction motor (EM2), to a third electronic electrical energy conversion unit configured to provide one or more voltage levels different from those of the Battery unit (B) wherein said reversible electric machine (EM1) is arranged to receive mechanical energy and charge said battery unit (B) via said first electronic conversion unit (EL1); wherein the reversible electric machine (EM1), the electric traction motor (EM2) and the hydraulic pump (9) are carried by the hollow beam.

Description

[0001] AGRICULTURAL PROCESSING VEHICLE WITH HYBRID OR ELECTRIC POWER SUPPLY AND ELECTRIC TRACTION

[0002] DESCRIPTION

[0003] Field of invention

[0004] The invention relates to the field of electric-powered agricultural vehicles, and in particular tractors, such as specialized vineyard tractors.

[0005] Specifically, the present invention relates to a common multipurpose platform for the production of electric-powered agricultural vehicles that can be configured as either fully electric or hybrid electric vehicles.

[0006] More specifically, the present invention relates to electric-powered vehicles independently equipped with a mechanical power take-off (PTO) also driven by an electric motor, of the type found on tractors for connection to agricultural equipment such as shredders, tillers, or other operating machines, or to hydraulic pumps.

[0007] State of the art

[0008] Currently, electric-powered agricultural vehicles are known, and have been developed in recent years primarily to reduce fuel consumption and pollution associated with vehicles used for various operations.

[0009] To address this problem, full electric vehicles are available. While they reduce pollution, they also require significant space and weight due to both the electric motor and the batteries required to allow the agricultural vehicle to move and operate the work tools, or PTOs.

[0010] Furthermore, given the load these vehicles must support, their range is significantly reduced in electric applications.

[0011] So-called "split power" hybrid solutions are also known, which combine electric motors with an internal combustion engine.

[0012] In these configurations, a first electric motor acts as a generator when the crankshaft rotates, transforming mechanical energy into electrical energy, which powers the agricultural vehicle and its consumers via a second electric motor.

[0013] These solutions offer performance advantages, but they also require space and bulk that are difficult to find on current agricultural vehicles. Publication WO2023067494, in the name of the same applicants, also discloses an agricultural vehicle equipped with an electric traction kit that can be adapted to different agricultural vehicles powered by an internal combustion engine, without requiring substantial structural modifications to the vehicle itself.

[0014] This solution achieves the goal of being both practical to use and simple and cost- effective to produce, allowing installation while maintaining the overall dimensions and functional characteristics of current agricultural tractors.

[0015] However, known systems present some limitations related to the difficulty for manufacturers in configuring, with limited adaptations to the same platform, a fully electric or hybrid vehicle depending on performance and usage needs.

[0016] Scope of the Invention

[0017] The current state of the art therefore highlights the need for a multipurpose electric-powered agricultural vehicle architecture that allows, with minimal structural intervention, the production of either an electric-powered agricultural vehicle powered by all-electric energy or a hybrid electric-powered agricultural vehicle equipped with an on-board internal combustion engine.

[0018] Brief description of the invention

[0019] These goals were achieved by developing an agricultural vehicle whose basic architecture includes a reversible electric machine connected to the PTO and an electric traction motor decoupled from the reversible machine and connected to the vehicle's wheels or tracks.

[0020] The vehicle's architecture also includes at least one electric battery pack connected to a first electronics unit so it can supply or receive energy from the reversible machine, and a further electronics unit configured to power the electric traction motor.

[0021] Furthermore, the reversible machine is designed to receive mechanical energy from a potential internal combustion engine, convert the received mechanical power into electrical energy, and charge the batteries via the second electronics unit.

[0022] A first advantage is that, with minimal adjustments, the agricultural vehicle can be configured for fully electric or hybrid operation with an internal combustion engine on board. This flexibility is provided by a master-slave operating logic, whereby the electric machine dedicated to traction receive power from the mains, regardless of the operating status of the electric machine dedicated to the mains supplying the PTO and hydraulic services. In a purely electric operating configuration, this second machine would also receive energy from the batteries, while in a hybrid configuration, it would return energy to the power line based on the demands of the traction motor.

[0023] A second advantage of the invention is the optimization of the required space and overall dimension.

[0024] An additional advantage is the reduction in production costs associated with offering both fully electric and hybrid versions.

[0025] List of Drawings

[0026] These and other advantages will be better understood by anyone skilled in the art from the following description and the accompanying drawings, provided as non-limiting examples, wherein:

[0027] - Fig. 1 shows a functional diagram of a first embodiment of the vehicle of the invention;

[0028] - Figs. 2a, 2b, and 2c show the architecture of the agricultural vehicle of Fig.

[0029] 1 in three-quarter, side, and plan views, respectively;

[0030] - Fig. 3 shows a functional diagram of a second embodiment of the vehicle of the invention;

[0031] - Figs. 4a, 4b, and 4c show the architecture of the agricultural vehicle of Fig.

[0032] 3 in three-quarter, side, and plan views, respectively.

[0033] Detailed description

[0034] With reference to the attached drawings, embodiments of an agricultural vehicle according to the invention are described, for example, a tractor 1 .

[0035] In its most general aspects, the structure of vehicle 1 is of the type equipped with hubs R for front and rear traction wheels or tracks connected to respective parallel axles 5 and driven by a mechanical traction transmission arranged along the longitudinal axis of vehicle frame 4, and in turn connected to an electric traction motor EM2 via a gearbox assembly 7 of a known type. As illustrated in the figure, frame 4, preferably H-shaped, comprises a hollow beam T to which the front and rear axles 5 are mounted. The vehicle also includes a reversible electric machine or motor-generator EM1 , electrically and mechanically decoupled from traction motor EM2 and connected via a transmission 8 to a rear-mounted mechanical power take-off (PTO) and, where applicable, to one or more hydraulic pumps 9 for powering the tractor's power steering and hydraulic equipment towed by the tractor or mounted to the PTO.

[0036] Both traction motor EM2 and reversible machine EM1 are then connected to a battery pack B.

[0037] Specifically, motor-generator EM1 is connected to batteries B via a first electronic electrical conversion unit EL1 , preferably comprising an inverter that powers a high-voltage power distribution unit (HV-PDU) connected to the batteries and other vehicle-related equipment 10, such as the alternator and air conditioning. Still referring to Figures 1 and 3, traction motor EM2 is in turn connected to batteries B via a second electronic electrical conversion unit EL2 and preferably includes an inverter also connected to the HV-PDU distribution unit.

[0038] Advantageously, according to the invention, reversible electric machine EM1 is therefore designed both to receive mechanical energy and charge said batteries B via said second electronic conversion unit EL1 and to receive electrical energy from the batteries and transfer mechanical energy to the PTO and any hydraulic pumps 9.

[0039] Preferably, furthermore, batteries B are connected at the output to a high-low voltage electronic power converter 1 1 , in the case described, a 48V DC / DC converter configured to power, via a low-voltage distribution unit LV-PDU, both low-voltage consumers 12 and an electric PTO intended to operate electrically operated agricultural equipment.

[0040] Figures 2a-2c illustrate an agricultural vehicle structure 1 based on the diagram in Figure 1 , in which traction motor EM2 is located next to vehicle frame 4, parallel to the transmission line and between two wheel axles 5, and is engaged with the transmission via a reduction gear unit 6. According to the embodiment illustrated in the figures, reduction gear 6 is preferably housed in a spacer D that rigidly connects a front portion F of hollow beam T to a rear portion P of hollow beam T. Advantageously, this solution allows for a favorable transmission ratio, for example, approximately three, and allows for the nominal speed of the motor to be increased to approximately 6000 rpm at the gearbox input while maintaining a relatively small external diameter of electric motor EM2.

[0041] In the example illustrated, the overall external diameter of motor EM2 is approximately 210 mm and extends in length parallel to the longitudinal dimension of the vehicle frame to accommodate the number of magnets needed to develop sufficient torque to produce 50 kW of power, identified in the example described here as a power equivalent to the power available to similar internal combustion engine tractors.

[0042] In greater detail, in the example described, traction motor EM2 has the following characteristics:

[0043] Nominal power: 50 kW

[0044] Nominal speed: 6000 rpm;

[0045] Nomial torque: 80 Nm;

[0046] Outer diameter: 210 mm;

[0047] Axial length: 410 mm.

[0048] In the embodiment described, in order to prepare reversible machine EM1 for coupling with an internal combustion engine, taking into account the vehicle's dimensional and layout constraints and simultaneously making it efficient both in battery charging and in power take-off (PTO) operation, a motor generator with the following characteristics was identified: Nominal power: 35 kW;

[0049] Nominal speed: 2600 rpm;

[0050] Nominal torque: 130 Nm;

[0051] Axial length: 250 mm.

[0052] It was also found advantageous to have a releasable joint 13 for connection to an ICE internal combustion engine, visible in the diagram in Fig. 3, in this case achieving a slightly greater axial length, equal to approximately 340 mm in the case described.

[0053] Advantageously, with these characteristics, the minimum power output of reversible machine EM1 was achieved, sufficient for the most demanding operations in the vehicle's field of application, even in "Full Electric" mode and therefore in the absence of the internal combustion engine.

[0054] Furthermore, in the case of coupling with an internal combustion engine, an engine EM1 was advantageously chosen with a nominal speed substantially equal to the maximum speed of the internal combustion engine.

[0055] Figures 4a-4c illustrate an embodiment of the vehicle structure according to the invention in the hybrid version, i.e., comprising an ICE internal combustion engine coupled to the EM1 motor generator according to the diagram in Fig. 3.

[0056] From figures 4a-4c, where the same numerical references used previously have been maintained, a partially different arrangement of the various components can be observed, while the essential components of the structure remain unchanged: the shape and dimensions of the frame, the motion and transmission components, and the location of motors EM1 and EM2.

[0057] The differences between the two embodiments shown in Figures 1 -2 and 3-4 therefore are the absence of the ICE internal combustion engine in the "full electric" vehicle shown in Figures 1 -2, with the provision of larger and more capacious B batteries in the space freed up by the absence of the internal combustion engine, and the connection of motor generator EM1 to the primary shaft of the ICE engine via joint 13.

[0058] Specifically, in the embodiment shown in Figures 3-4, the connection of motor generator EM1 to the shaft of the ICE internal combustion engine was designed so that motor EM1 can always transmit mechanical power to the PTO, but can include or exclude the connection to the internal combustion engine via an automatic mechanical clutch that allows motor EM1 shaft to be decoupled from the ICE shaft, ensuring the axial compactness is as possible. In fact, in purely electric mode, it would be counterproductive and potentially harmful for the motor generator to drive the ICE, thus subtracting available power from the PTO; therefore, the clutch disengages the mechanical connection between motor EM1 and the ICE. In hybrid mode, upon ignition, the clutch gradually releases the ICE so as not to impact its starting dynamics.

[0059] According to the invention, the connection between the internal combustion engine and electric motor EM1 occurs exclusively when the former is switched on, i.e., when it is necessary to produce electricity to recharge batteries B and / or power traction motor EM2.

[0060] Furthermore, when the ICE is equipped, battery B is positioned above the electric motor EM1 and between the ICE and electric motor EM1 . When the vehicle is full electric, battery B occupies part or all of the space of the ICE, i.e., the front position of battery B is further forward than the front position of the reversible electric motor EM1 so as to be able to accumulate more energy. Also in the fully electric version, at least one of the electric conversion units EL1 , preferably both EL2, are positioned under battery B in a front position further forward than that of the reversible electric motor EM1 .

[0061] Furthermore, according to the embodiment illustrated in the figures, the ICE is rigidly connected to a casing that houses the reversible electric machine EM1 , thus allowing easier axial alignment for the torque transmission connection between the crankshaft and the rotor of the reversible electric machine EM1 .

[0062] The invention offers numerous technical advantages, particularly with regard to the possibility, with minimal adaptations, of preparing an electric-powered agricultural vehicle in both a fully electric version and a hybrid version including a combustion engine, while keeping the overall dimensions and maintaining the operational capabilities of both the traction and the mechanical, electrical, and hydraulic power take-offs unchanged in both versions.

[0063] The present invention has been described according to preferred embodiments, but equivalent variants may be conceived without departing from the scope of protection granted.

Claims

CLAIMS1. Hybrid or electric powered agricultural vehicle with electric traction, comprisingA frame (4) having a longitudinal hollow beam (T) a power take-off (PTO) configured to provide the connection and operation of mechanically operated agricultural equipment, an electric power take-off (EPTO) a front reversible electric machine (EM1 ) mechanically connected to said power take-off (PTO) via a shaft (8) housed in the hollow beam, a hydraulic pump (9) connected in torque transmission to the shaft, preferably to operate a power steering of the vehicle and hydraulic equipment an electric traction motor (EM2) mechanically decoupled from said reversible machine (EM1 ), fixed to the frame (4) of the vehicle and connected by mechanical transmission means to one or more wheels or tracks (R) of the vehicle, the electric traction motor (EM2) being interposed between the front and rear axles (5) of the frame (4) at least one electric battery unit (B) connected to a first electronic electrical conversion unit (EL1 ) configured to supply energy to, or receive energy from, said reversible machine (EM1 ), and to a second electronic electrical conversion unit (EL2) configured to power said electric traction motor (EM2), to a third electronic electrical energy conversion unit configured to provide one or more voltage levels different from those of the Battery unit (B) wherein said reversible electric machine (EM1 ) is arranged to receive mechanical energy and charge said battery unit (B) via said first electronic conversion unit (EL1 ); wherein the reversible electric machine (EM1 ), the electric traction motor (EM2) and the hydraulic pump (9) are carried by the hollow beam.

2. Vehicle according to claim 1 , comprising front and rear axles (5) of traction wheels (R) arranged parallel and spaced along a longitudinal line of a frame (4),wherein said traction motor (M2) is placed parallel and adjacent to said longitudinal line.

3. Vehicle according to one of the preceding claims, wherein the frame comprises a front portion comprising a front axle; a front portion of the hollow beam and a rear portion comprising a rear axle and a rear portion of the hollow beam; a hollow structural element for connecting the front portion of the hollow beam to the rear portion of the hollow beam; wherein the electric traction motor (EM2) is carried by the spacer.

4. Vehicle according to claim 3, wherein the pump (9) is carried by the spacer.

5. Vehicle according to one of the preceding claims, wherein said reversible machine (EM1 ) is connected to the battery unit (B) via a first electronic electrical conversion unit (EL1 ) and a high voltage electricity distribution unit (HV-PDU) connected to the batteries and to further users (10) for use by the vehicle.

6. Vehicle according to one of the preceding claims, wherein said traction motor (EM2) is connected to the battery unit (B) via a second electronic electrical conversion unit (EL2) and said high voltage electricity distribution unit (HV-PDU) connected to the battery unit and to further users (10) for use by the vehicle.

7. Vehicle according to one of the preceding claims, wherein said battery unit (B) are connected at the output to an electronic power converter (1 1 ) configured to power, via a second distribution unit (LV-PDU), both utility devices on board the vehicle (12) and utility devices on external equipment by means of the electric power take-off (E-PTO).

8. Vehicle according to claim 7, wherein said traction motor (EM2) is coupled with the vehicle transmission via a reduction unit (6)9. Vehicle according to one of the preceding claims, comprising an internalcombustion engine (ICE) coupled with said reversible machine (EM1 ).

10. Vehicle according to claim 9, wherein said internal combustion engine (ICE) is coupled with said reversible machine (EM1 ) via a decoupleable joint (13).1 1 . Vehicle according to claim 9 or 10, characterized in that the coupling of said internal combustion engine (ICE) with said reversible machine (EM1 ) is configured in such a way that the electric machine (EM1 ) can always transmit mechanical power to the power take-off (PTO) and in that it comprises means for including or excluding the coupling with the internal combustion engine.

12. Vehicle according to one of claims 9-1 1 comprising control means configured to enable the coupling between said internal combustion engine (ICE) and said reversible electric motor (EM1 ) exclusively when the internal combustion engine (ICE) is switched on.

13. Vehicle according to one of claims 9-12, wherein said internal combustion engine (ICE) is mechanically coupled to said reversible electric machine (EM1 ) via a clutch and is arranged cantilevered with respect to the axis of the front wheels.

14. Full-electric vehicle according to any of claims 1 to 8, wherein the battery unit (B) has a first front face arranged in front of a second front face of the reversible electric machine (EM1 ).

15. Full-electric vehicle according o any of claims 1 to 8, wherein at least one of the first and second electronic electrical conversion units (EL1 ; EL2) is arranged in front of the reversible electric machine (EM1 ), preferably under the battery unit

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