AGRICULTURAL WORK MACHINE

Description

[0001] The present invention relates to an agricultural machine, in particular a tractor, according to the preamble of claim 1. Furthermore, the present invention relates to a method for operating an agricultural machine according to the preamble of claim 12.

[0002] From EP 2 801 492 B1, a vehicle is known which is hybrid-driven, i.e., which, in addition to a drive unit designed as an internal combustion engine, also has an electric drive unit. A battery-electric energy storage system is provided for storing electrical energy that can be made available to the electric drive unit when needed. It is known that, for optimal operation of battery-electric energy storage systems, which enable the full utilization of their performance potential with minimal loss of service life, they must be operated within a specific operating temperature range. To ensure operation within this temperature range, battery-electric energy storage systems have a separate cooling circuit. The prevailing ambient temperatures have a significant influence on operation within this temperature range.According to EP 2 801 492 B1, the battery-electric energy storage system is to be integrated into an existing cooling circuit of the vehicle, which serves to cool the combustion engine. At temperatures below the operating temperature range, waste heat from the combustion engine is used to preheat the energy storage system via a coolant in the vehicle's cooling circuit. Once the operating temperature range is reached, the energy storage system typically requires cooling during operation. The circuits provided for this purpose in EP 2 801 492 B1 are complex in terms of design and operation.

[0003] The invention is therefore based on the objective of providing an agricultural machine and a method for operating an agricultural machine, which is characterized by a structurally and operationally simplified design for preheating a battery-electric energy storage device.

[0004] This problem is solved according to the invention by an agricultural machine having the features of claim 1 and a method for operating an agricultural machine having the features of dependent claim 12. Advantageous embodiments are the subject of the dependent claims.

[0005] According to claim 1, an agricultural machine, in particular a tractor, is proposed, comprising at least one drive unit, a hydraulic system for operating drive and / or working units of the machine and / or an adapted implement, and a battery-electric energy storage device associated with the machine. According to the invention, a hydraulically operated preheating system for heating the battery-electric energy storage device is associated with the energy storage device and is configured for connection to the hydraulic system of the machine or the implement.

[0006] The preheating system associated with the energy storage unit utilizes the existing hydraulic system of the machine and the pressurized hydraulic oil within it, which heats up during operation. The power losses of the machine's hydraulic system are converted into heat, which is largely absorbed by the hydraulic fluid. These power losses include pressure losses due to pipe friction and flow deflections, leakage losses, and losses due to throttling processes caused by local resistances within the hydraulic system. Thus, the power losses generated in the hydraulic system are used to preheat the energy storage unit.

[0007] The hydraulically operated preheating system allows for faster heating of the battery-electric energy storage device compared to the prior art, as the hydraulic oil, which is usually under high pressure, heats up faster than the combustion engine after a cold start. This is particularly true at low ambient temperatures, below 5°C. At ambient temperatures around or below freezing, the hydraulically operated preheating system enables the battery-electric energy storage device to reach its operating temperature range.

[0008] Preferably, the at least one drive unit can comprise at least one electric drive unit. More preferably, the machine can additionally comprise a drive unit designed as an internal combustion engine.

[0009] To ensure that the battery-electric energy storage device is preheated by the preheating system in such a way that it reaches its operating temperature range as quickly as possible when its operating temperature is below this range, the driven machine and / or the battery-electric energy storage device can include a control device for activating the preheating system. This control device allows the preheating system to be controlled or regulated during the preheating process. Once the battery-electric energy storage device reaches its specific operating temperature range, the control device can terminate the preheating process.If a change in the operating state of the machine causes the operating temperature to drop below the operating temperature range, the preheating system is controlled accordingly to achieve an operating temperature within the operating temperature range again by reheating.

[0010] Providing the control device in the battery-electric energy storage system has the advantage that it can also perform the task of the necessary storage management of the battery-electric energy storage system.

[0011] A structural simplification of the machine's design can be achieved by providing the preheating system with two connections for linking to hydraulic connections located at the rear and / or front of the machine. This allows the preheating system to be connected to a pressure line and a return line of the hydraulic system. This eliminates the need for additional modifications to the machine regarding further process connections. The hydraulic preheating system can be connected to the machine's hydraulic system using a standardized quick-connect coupling system and thus supplied with heated hydraulic oil from the hydraulic system.

[0012] In the case of using the energy storage device with the preheating system according to the invention on the attachment, it is advantageous to provide additional connections on the attachment if the hydraulic connections available on the working machine are already occupied by the attachment.

[0013] Preferably, the preheating system can include an oil-coolant heat exchanger that connects the preheating system to a coolant circuit of the battery-electric energy storage system. This allows waste heat contained in the hydraulic oil to be transferred directly to the cooling medium circulating in the battery-electric energy storage system's coolant circuit. Once the operating temperature range of the battery-electric energy storage system is reached through preheating, the energy storage system's coolant circuit serves to maintain the operating temperature within this range. This is particularly necessary at ambient temperatures that exceed the operating temperature range.

[0014] Preferably, an actuated valve and an orifice plate can be installed upstream of the oil-coolant heat exchanger. The actuated valve can be used to allow the flow of hydraulic oil from the hydraulic system of the machine for the heating process or to interrupt it once the operating temperature range has been reached. The orifice plate can be used to prevent an impermissible pressure gradient from occurring in the preheating system. Furthermore, the throttling effect of the orifice plate causes additional heating of the hydraulic oil flowing through it before it reaches the downstream oil-coolant heat exchanger. Finally, the maximum flow rate supplied to the oil-coolant heat exchanger can be regulated by selecting the appropriate orifice plate.

[0015] According to further training, the energy storage device can include at least one temperature sensor that transmits measurement signals to the control device for evaluation.

[0016] Thus, the control device can actuate the valve depending on the temperature. The preheating system can then be supplied with hydraulic oil via the valve, provided the operating temperature range of the energy storage unit has not yet been reached.

[0017] Preferably, a safety valve can be installed upstream of the oil-coolant heat exchanger. This valve short-circuits the two connections that fluidically link the heating system to the pressure and return lines of the hydraulic system if a hydraulic pressure threshold in the preheating system's hydraulic circuit is exceeded. The safety valve protects the preheating system from impermissible pressure. In particular, the safety valve can be designed as a pressure relief valve, preferably a pilot-operated one.

[0018] As a further protective mechanism, a check valve can be installed upstream of the connection that links the preheating system to the return line of the hydraulic system. The check valve only opens in the direction of the return line. This prevents damage to the preheating system if the connections are accidentally reversed when connecting the preheating system to the hydraulic system.

[0019] In particular, the battery-electric energy storage unit can be interchangeably mounted on the machine or attachment. The energy storage unit's preheating system, which is connected to the machine's hydraulic system via only two connections, simplifies battery replacement. Similarly, the battery-electric energy storage unit's placement on the machine or attachment is structurally simpler and less inflexible. A connection to the machine's existing cooling circuit, as required in the prior art, is not necessary.

[0020] According to a preferred embodiment, the battery-electric energy storage system and the preheating system can be designed as a single module housed in a common casing. The resulting advantages include short hydraulic lines for the preheating system, the proximity of the preheating system to the energy storage system, and easy retrofitting to existing machinery and / or attachments that have at least one electric drive unit to be supplied with energy by the energy storage system.

[0021] Alternatively, the preheating system on the oil-coolant heat exchanger can have additional connections that allow it to be connected to corresponding connections of the coolant circuit of the energy storage system.

[0022] Furthermore, the problem initially set out is solved by a method for operating an agricultural machine with the features of the subordinate claim 12.

[0023] According to claim 12, a method for operating an agricultural machine, in particular a tractor, is proposed, wherein the machine comprises at least one drive unit, a hydraulic system for operating drive and / or working units of the machine and / or an adapted implement, and a battery-electric energy storage device associated with the machine, wherein the battery-electric energy storage device is preheated by a hydraulically operated preheating system to achieve an operating temperature range in which the energy storage device is optimally operated, wherein the preheating system is connected to the hydraulic system of the machine for operation.

[0024] In particular, the preheating system can be controlled by a control device in a temperature-dependent manner, wherein at least one temperature sensor for determining the temperature in the energy storage unit transmits measurement signals to the control device for evaluation, and wherein the control device can control a valve which is arranged in a supply line between an oil-coolant heat exchanger of the preheating system and the hydraulic system of the working machine.

[0025] Regarding further design options and the advantages of the procedure, reference is made to the explanations concerning the proposed working machine.

[0026] The present invention is explained in more detail below with reference to an embodiment illustrated in the drawings.

[0027] They show: Fig. 1 schematically and by way of example an agricultural machine; Fig. 2 schematically and by way of example a rear partial view of the machine; and Fig. 3 a simplified hydraulic circuit diagram of a preheating system.

[0028] In Fig. 1Figure 1 schematically illustrates an agricultural machine 1, which is exemplified as a tractor 2. The machine 1 can comprise a drive unit 3 designed as an internal combustion engine and a transmission associated with the drive unit 3. The machine 1 can further comprise at least one electric drive unit 4 and a hydraulic system 5 for operating drive and / or working units of the machine 1. The drive unit 3 designed as an internal combustion engine and / or the at least one electric drive unit 4 and / or the hydraulic system 5 can also drive an implement adapted to the machine 1 – not shown – in particular a trailed or towed implement.A control device 6 is provided for controlling the drive unit 3, designed as an internal combustion engine, and / or the electric drive unit 4, as well as the hydraulic system 5 of the working machine 1. One or both drive units 3, 4 supply mechanical drive energy to driven components, such as a hydraulic pump of the hydraulic system 5.

[0029] In the rear area of ​​the work machine 1, as in Fig. 2A hydraulic connection arrangement 7 with so-called remote connections 8A, 8B is shown schematically and by way of example. This arrangement serves to connect external hydraulic consumers, in particular those of an attachment. Since these hydraulic consumers are each controlled or operated via a control valve, the remote connections 8A, 8B each comprise at least two connections to connect the hydraulic consumer(s) to a pressure line P and a return line T. Another hydraulic connection arrangement 7 of the type described above can be arranged in the front area of ​​the machine 1.

[0030] A battery-electric energy storage device 9 is assigned to the working machine 1. The battery-electric energy storage device 9 can be permanently installed in or on the working machine 1. Alternatively, the battery-electric energy storage device 9 can be detachably connected to the working machine 1. Likewise, the battery-electric energy storage device 9 can be permanently or detachably arranged on the attachment. Arrangement on the attachment is advantageous if the attachment itself has at least one electric drive unit. A control device 10 can be integrated into the battery-electric energy storage device 9, which, among other things, serves to manage the energy storage capacity of the battery-electric energy storage device 9.

[0031] Furthermore, the energy storage unit 9 includes a hydraulically operated preheating system 11. The preheating system 11 serves to preheat the energy storage unit 9 so that it can be operated as quickly as possible within its intended operating temperature range. Operating the battery-electric energy storage unit 9 within its operating temperature range is of great importance for its service life and for fully utilizing its performance potential. In particular, operating the energy storage unit 9 at ambient temperatures significantly below its operating temperature range leads to a reduction in its service life.

[0032] In Fig. 3A simplified hydraulic circuit diagram of the preheating system 11 is shown. The preheating system 11 comprises two connections 12, 13 for connection to two of the hydraulic connections 8A, 8B located at the rear or front of the machine 1. The preheating system 11 is connected to the pressure line P via connection 12 and to the return line T of the hydraulic system 5 via connection 13.

[0033] The preheating system 11 comprises an oil-coolant heat exchanger 16, which connects the preheating system 11 to a schematically represented coolant circuit 24 of the battery-electric energy storage unit 9. A controllable valve 14 and an orifice plate 15 are located upstream of the oil-coolant heat exchanger 16. Furthermore, a check valve 17 is located upstream of the connection 13, which connects the preheating system 11 to the return line T of the hydraulic system 5. The check valve 17 opens only in the direction of the return line T of the hydraulic system 5.

[0034] A safety valve 18 is installed upstream of the oil-coolant heat exchanger 16. The safety valve 18 is arranged in a branch line 19 that runs parallel to the hydraulic line 20, which connects the oil-coolant heat exchanger 16 to the ports 12 and 13. In particular, the safety valve 18 can be designed as a pressure relief valve, preferably a pilot-operated one.

[0035] The energy storage device 9 includes at least one temperature sensor 21, which transmits measurement signals for evaluation to the control device 10 of the energy storage device 9 and / or the control device 6 of the working machine 1.

[0036] Valve 14 is controlled by control device 10 and / or control device 6, depending on the temperature. For this purpose, control signals from control device 10 are transmitted to valve 14 via a signal line 22. If the operating temperature detected by at least one temperature sensor 21 is below the operating temperature range of the energy storage device 9, valve 14 opens. The preheating system 11 associated with the energy storage device 9 utilizes the existing hydraulic system 5 and the pressurized hydraulic oil contained therein, which heats up during operation of the machine 1 due to the power losses of the hydraulic system 5.

[0037] Once the operating temperature range of the energy storage unit 9 has been reached through preheating, the valve 14 is closed. If a change in the operating state of the working machine 1 causes the operating temperature detected by the at least one temperature sensor 21 to fall below the operating temperature range, for example due to an interruption of operation, the valve 14 is actuated again to reopen it.

[0038] The hydraulic oil coming from hydraulic system 5 is throttled by the orifice plate 15. This throttling by the orifice plate 15 results in additional heating of the flowing hydraulic oil before it reaches the oil-coolant heat exchanger 16. Furthermore, the orifice plate 15 can be used to regulate the maximum flow rate supplied to the oil-coolant heat exchanger 16. In addition, the orifice plate 15 can be used to protect the preheating system 11 from the occurrence of an impermissible pressure gradient.

[0039] The safety valve 18 can short-circuit the two ports 12 and 13 if a threshold value for the hydraulic pressure in the hydraulic line 20 of the preheating system 11 is exceeded. The hydraulic oil supplied via port 12 can flow directly to port 13 via the safety valve 18 and the branch line 19, bypassing the oil-coolant heat exchanger 16.

[0040] The non-return valve 17 is designed to prevent damage to the preheating system 11 in the event of an accidental incorrect connection of the ports 12, 13, where port 13 is connected to the pressure line P instead of the return line T of the hydraulic system 5.

[0041] According to the in Fig. 3 In the illustrated embodiment, the preheating system 11 and the battery-electric energy storage device 9 can be arranged in a common housing 23. This allows the preheating system 11 and the battery-electric energy storage device 9 to be designed as a single module. The modular design enables greater flexibility in use and arrangement.

[0042] However, an arrangement is also conceivable in which the preheating system 11 and the battery-electric energy storage unit 9 each form separate modules. For this purpose, the oil-coolant heat exchanger 16 and the coolant circuit 24 of the battery-electric energy storage unit 9 can be designed with separate connections that can be connected to each other by suitable supply lines.

[0043] The modular design of the preheating system 11 and the battery-electric energy storage unit 9 as one module or as two separate modules offers the advantage of easy retrofitting to the working machine and / or an attachment to be adapted. Reference symbol list

[0044] 1 Working machine 2 Tractor 3 Drive unit 4 Drive unit 5 Hydraulic system 6 Control device 7 Hydraulic connection arrangement 8 A Remote connection 8 B Remote connection 9 Battery-electric energy storage 10 Control device 11 Preheating system 12 Connection 13 Connection 14 Valve 15 Cover plate 16 Oil-coolant heat exchanger 17 Check valve 18 Safety valve 19 Branch line 20 Hydraulic line 21 Temperature sensor 22 Signal line 23 Housing 24 Coolant circuit P Pressure line T Return line

Claims

1. An agricultural working machine (1), in particular a tractor (2), comprising at least a propulsion unit (3, 4), a hydraulic system (5) for operating propulsion assemblies and / or working assemblies of the working machine (1) and / or of an adapted mounted implement, as well as a battery-electric energy storage device (9) associated with the working machine (1), wherein a hydraulically operated preheating system (11) for heating the battery-electric energy storage device (9) is associated with the energy storage device (9), the preheating system being configured for connection to the hydraulic system (5) of the working machine (1), characterized in that the preheating system (11) has two connections (12, 13) for connection to hydraulic connections (8A, 8B) disposed in the rear region and / or front region of the working machine (1) in order to connect the preheating system (11) to a pressure line (P) and to a return line (T) of the hydraulic system (5).

2. The agricultural working machine (1) according to claim 1, characterized in that the working machine (1) and / or the battery-electric energy storage device (9) comprises a control device (6, 10) for controlling the preheating system (11).

3. The agricultural working machine (1) according to claim 1 or claim 2, characterized in that the preheating system (11) comprises an oil-coolant heat exchanger (16) which connects the preheating system (11) to a coolant circuit (24) of the battery-electric energy storage device (9).

4. The agricultural working machine (1) according to claim 3, characterized in that a valve (14) to be controlled and an orifice plate (15) are connected upstream of the oil-coolant heat exchanger (16).

5. The agricultural working machine (1) according to one of claims 2 to 4, characterized in that the energy storage device (9) comprises at least one temperature sensor (21) which transmits measurement signals to the control device (6, 10) for evaluation.

6. The agricultural working machine (1) according to claim 5, characterized in that the control device (6, 10) controls the valve (14) as a function of temperature.

7. The agricultural working machine (1) according to one of claims 3 to 6, characterized in that a safety valve (18) is connected upstream of the oil-coolant heat exchanger (16), by which safety valve the two connections (12, 13) can be short-circuited in the event that a threshold value for the hydraulic pressure in the hydraulic circuit of the preheating system (11) is exceeded.

8. The agricultural working machine (1) according to one of claims 1 to 7, characterized in that a check valve (17) is connected upstream of the connection (13) which connects the preheating system (11) to the return line (T) of the hydraulic system (5).

9. The agricultural working machine (1) according to one of the preceding claims, characterized in that the battery-electric energy storage device (9) is disposed on the working machine (1) or the mounted implement in an interchangeable manner.

10. The agricultural working machine (1) according to one of the preceding claims, characterized in that the battery-electric energy storage device (9) and the preheating system (11) are constructed as a module disposed in a common housing (23).

11. A method for operating an agricultural machine (1), in particular a tractor (2), which comprises at least a propulsion unit (3, 4), a hydraulic system (5) for operating propulsion assemblies and / or working assemblies of the working machine (1) and / or of an adapted mounted implement, as well as a battery-electric energy storage device (9) associated with the working machine (1), wherein the battery-electric energy storage device (9) is preheated by a hydraulically operated preheating system (11) in order to reach an operating temperature range in which the energy storage device (9) is optimally operated, wherein the preheating system (11) is connected to the hydraulic system (5) of the working machine (1) for operation, characterized in that the preheating system (11) has two connections (12, 13) for connection to hydraulic connections (8A, 8B) disposed in the rear region and / or front region of the working machine (1) in order to connect the preheating system (11) to a pressure line (P) and to a return line (T) of the hydraulic system (5).

12. The method according to claim 11, characterized in that the preheating system (11) is controlled as a function of temperature by a control device (6, 10), wherein at least one temperature sensor (21) for determining the temperature in the energy storage device (9) transmits measurement signals to the control device (6, 10) for evaluation, and in that a valve (14) which is disposed in a supply line (20) between an oil-coolant heat exchanger (16) of the preheating system (11) and the hydraulic system (5) of the working machine (1) is controlled by the control device (6, 10).