Agricultural vehicle

Abstract

Agricultural vehicle with an electro-pneumatic tire pressure control system (16), wherein the tire pressure control system (16) comprises an electronic control unit (22) for regulating tire pressure and means for determining or indicating the slip between the ground (11) and the tires (18, 20) of the vehicle (10), wherein a mathematical equation or a map (50) is stored in the electronic control unit (22) and the control of the tire pressure is carried out on the basis of the mathematical equation or the map (50) depending on the slip, characterized in that the control unit (22) adapts the mathematical equation or the map (50) according to parameters relating to a tire type, a soil type, a soil condition and / or a driving speed, so that, depending on the parameters stored in the mathematical equation or the map, an optimal slip is achieved for the efficiency of the tire-ground contact.

Description

[0001] The invention relates to an agricultural vehicle with an electro-pneumatic tire pressure control system, wherein the tire pressure control system comprises an electronic control unit for regulating tire pressure and means for determining or indicating the slip between the ground and the tire of the vehicle, wherein a mathematical equation or a characteristic map is stored in the electronic control unit and the control of the tire pressure is carried out on the basis of the mathematical equation or the characteristic map as a function of the slip.

[0002] Such tire pressure control systems, which are based on the use of special characteristic curves or look-up tables for tire pressure adjustment, are known, for example, from DE 103 36 330 B3, US 6 212 464 B1, EP 2 018 991 A1 and US 6 144 295 A. Based on these, DE 103 36 330 B3 determines an inflation pressure leading to a maximum coefficient of friction; US 6 212 464 B1 adjusts the slip values ​​used to specify the tire inflation pressure to the tire type and operating conditions; EP 2 018 991 A1 determines a maximum drivable speed dependent on the tire pressure, taking into account the tire size, tire type and / or gradient; and US 6 144 295 A determines a suitable tire inflation pressure for a given load-speed combination.

[0003] The object underlying the invention is seen as being to provide an agricultural vehicle with an electro-pneumatic tire pressure control system of the type mentioned at the outset with regard to a further improved tire pressure adjustment.

[0004] The problem is solved according to the invention by the teaching of claim 1. Further advantageous embodiments and developments of the invention are set forth in the dependent claims.

[0005] According to the invention, an agricultural vehicle of the type mentioned above is designed such that the control unit adapts the mathematical equation or the characteristic map according to parameters relating to a tire type, a soil type, a soil condition, and / or a driving speed, so that, depending on the parameters stored in the mathematical equation or the characteristic map, an optimal slip rate for the efficiency of the tire-soil contact is achieved. With such an automated tire pressure control system, the agricultural vehicle, for example a tractor, can be brought into and maintained in an optimal operating state, regardless of the operator's skills. The parameters contained in the mathematical equation or the characteristic map allow tire slip to be used as a control variable, or the tire pressure can be adjusted according to a determination or...The specified tire slip and the parameters contained in the mathematical equation or characteristic map can be efficiently controlled to, for example, optimize the vehicle's efficiency and save fuel. The slip between the ground and the tractor's tires can be determined and used as a control variable for adjusting the tire pressure by the electronic control unit. Here, the tire pressure does not need to be adjusted in fractions of a second; average values ​​can also be used as the control variable, since evacuating or inflating a tractor tire, and thus regulating the tire pressure, is often a slow process due to the size of the tires.

[0006] The means for determining or indicating slip can include a radar sensor or a positioning system (GPS). The slip can then be determined using a radar sensor commonly found in agricultural vehicles (such as tractors) or with the aid of positioning systems typically used in agriculture, and used as a control variable. Depending on the current slip rate, the tire pressure is increased or decreased based on one or more characteristic maps by adding or releasing air from the tires.

[0007] The means for determining or specifying slip may also include an input device. This input device may, for example, be installed in the vehicle's cabin, allowing an operator to make inputs that are also used as a basis for the control system. For instance, the operator can specify a target slip value or enter other parameters to be considered in the control system via the characteristic map, such as a desired tire pressure as a target pressure value (setpoint tire pressure).

[0008] Furthermore, means for determining vehicle speed or axle loads can be provided, for example, speed sensors or force sensors (pressure sensors, strain gauges, etc.), and the tire pressure can be regulated depending on the vehicle speed or axle load. This allows the optimal tire pressure to be determined based on the vehicle speed, assuming the speed indicates that the vehicle is on a road or at least not engaged in heavy towing or working in a field. The tire pressure can then be adjusted to the optimal pressure for transport or towing operations as a higher-level control. Whether such a higher-level control should be activated can be set by the operator via the aforementioned input device.

[0009] The tire pressure control can be activated by the operator via the input device or via an activation switch, if desired, or if, for example, the operating conditions are appropriate for preset parameters and slip control seems sensible.

[0010] Furthermore, changes and variations of the aforementioned parameters can also be reflected in the mathematical equation or in at least one characteristic map (or in further characteristic maps stored in the electronic control unit). The operator can specify relevant parameters for the tire type, such as tire manufacturer, tire size, tire width, construction, tread pattern, etc., using the input device of the electronic control unit. This triggers a corresponding algorithm that takes the tire type into account and forms the basis for tire pressure control. In this way, an optimal slip value for the respective tire type can be regulated by varying the tire pressure. Additionally, parameters for the ground type, such as sand, clay, grass, stubble field, etc., can be specified.This can be taken into account as a parameter setting, which is also entered by the operator, or can be provided by a commonly used GPS mapping system. Corresponding different algorithms for regulating tire pressure depending on slippage for driving on sand, clay, grass, stubble, etc., can be stored in the electronic control unit. Another parameter that influences the optimal selection of the control algorithm is the soil condition (loose, compacted, wet, moist, dry, etc.). The soil condition can also be specified by the operator and taken into account when selecting a suitable control algorithm or within the control algorithm itself. Furthermore, the driving speed can also be considered as a parameter.The vehicle speed can be determined via additional sensors and transmitted to the electronic control unit, or derived directly from the slip measurement and transmitted to the electronic control unit. Furthermore, axle load distribution can also be considered as a parameter in the control algorithm, whereby the axle load can be determined either by additional sensors or by the existing tire pressures.

[0011] Other data, which are not mentioned here but can be supplied via GPS due to increasing professionalization in agriculture, or which have been stored in mapping systems from the results of soil investigations, can also be used as input for the control algorithm.

[0012] With reference to the drawing, which shows an embodiment of the invention, the invention as well as further advantages and advantageous developments and embodiments of the invention are described and explained in more detail below.

[0013] It shows: Fig. 1 A schematic block diagram for an agricultural vehicle according to the invention

[0014] The Fig.Figure 1 shows an agricultural vehicle in the form of a tractor 10. This could also be another type of agricultural vehicle, such as a self-propelled sprayer or a harvester. The tractor 10 comprises front wheels 12 and rear wheels 14, which support it on a surface 11 (ground, road, field). These wheels and rear wheels are connected to an electro-pneumatic tire pressure control system and tire inflation system 16. The tire inflation system 16 is used to inflate or deflate tires 18 and 20 mounted on the wheels 12 and 14. Each wheel 12 and 14 is connected to corresponding rotary unions (not shown), which allow the tires 18 and 20 to be inflated and deflated while the tractor 10 is in motion.

[0015] The tire inflation system 16 comprises an electronic control unit 22 and a pneumatic system 24, which includes all the necessary pneumatic components of a tire inflation system 16 (compressor or pneumatic pump with air reservoir, electromagnetic valve or switching devices, etc.). Tire inflation systems 16 are known to those skilled in the art and need not be described in detail here. The pneumatic system 24 is connected to the wheels 12, 14 via pneumatic lines 26. Furthermore, pressure sensors 27 are provided in the pneumatic system 24 and / or in the pneumatic lines 26. These sensors detect the air pressure in the tires 18, 20 and, if necessary, transmit this information to the electronic control unit. The electronic control unit 22 is connected to the pneumatic system 24 and / or to the electromagnetic valve or switching devices located therein via a control line 28.

[0016] The tractor 10 further comprises a cab 30 in which an input device 32 is arranged, via which an operator can enter data for the automatic control of the tire inflation system 16. The input device 32 is electronically connected to the electronic control unit 22 via an input control line 34 or by radio.

[0017] The tractor 10 also includes a positioning system 36, for example a GPS system, and / or a radar sensor 38, each of which is also connected to the electronic control unit 22 via corresponding control lines 40 or 42, or in another known way.

[0018] Furthermore, a driving speed sensor in the form of a speed sensor 44 is provided on the rear wheel 14 of the tractor 10, which is connected to the electronic control unit 22 via a further control line 46.

[0019] Furthermore, the electronic control unit 22 includes a storage module 48 in which one or more characteristic maps 50 are stored, which are used to generate control signals for controlling the electromagnetic valves in the pneumatic device 24 of the tire inflation system 16.

[0020] The tractor 10 rests on a surface (such as grass, stubble field, arable land, sand, clay, road, etc.) via its tires 18, 20, which are inflated to a specific air pressure. As the tractor 10 moves across the surface, slippage occurs between the tires 18, 20 and the surface. The slippage value is determined using the position determination system 36 or the radar sensor 38 in conjunction with the rotational speed of the wheels 14, which is determined by the speed sensor 44. The former essentially measure or determine the actual speed of the tractor 10, while the rotational speed of the wheels 14 and their geometric dimensions are used to measure or determine the speed of the tractor 10 subject to slippage. The difference orThe ratio of the two speeds essentially allows a direct conclusion to be drawn about the slip value, which is used to control the tire inflation system 16 and thus to regulate the tire pressure.

[0021] The tire pressure can now be regulated either solely based on slippage, i.e., by a generally applicable map 50, or by a predefined mathematical or physical relationship that takes into account various constant parameters such as tire type, soil type, soil condition, speed, or axle load distribution on the vehicle. The tire pressure control can then be activated or deactivated as desired via the input device 32. For example, a generally applicable map 50 can be created for field operation or for driving on the road. If the operating conditions do not correspond to the conditions of the generally applicable map, the tire pressure control can be deactivated accordingly.

[0022] Furthermore, changes and variations of the aforementioned parameters can also be reflected in at least one characteristic map 50 (or in further characteristic maps stored in the electronic control unit 22), so that the tire type can also be taken into account. The operator can specify relevant parameters such as tire manufacturer, tire size, tire width, construction, tread pattern, etc., using the input device 32 of the electronic control unit 22, so that a corresponding algorithm, taking the tire type into account, is called up and used as the basis for tire pressure control. In this way, an optimal slip value for the respective tire type can be regulated by varying the tire pressure.

[0023] Furthermore, the soil type can also be taken into account (additionally, if required). For example, sand, clay, grass, stubble field, etc., can be specified as parameters by the operator via input device 32. It is also possible for a GPS mapping system, now well-established in agriculture, to be integrated into input device 32, and for the aforementioned parameters to be automatically specified via an electronic connection 52 in conjunction with the positioning system 36. For example, different algorithms for regulating tire pressure depending on slippage are stored in the electronic control unit for driving on sand as well as for driving on clay, grass, or stubble field, etc.

[0024] Another parameter that can influence the optimal selection of the control algorithm is the soil condition (loose, compacted, wet, moist, dry, etc.). This is also stored as an algorithm in separate characteristic curves 50 in the control unit 22, so that the soil condition can be specified as a variable by the operator.

[0025] Furthermore, the driving speed can also be taken into account as a parameter. The driving speed is continuously determined via the speed sensor 44, the radar sensor 38, or the position determination system 36 and transmitted to the control unit 22. It is also provided that the tire pressure control is only carried out if the driving speed remains above or below a certain value for a certain period of time, thus indicating a transition from field work to driving on the road, or vice versa, and the tire pressure is adjusted according to preset values ​​or values ​​adjustable by the operator via the input device 32.

[0026] Furthermore, axle load distribution can also be taken into account as a parameter in the control algorithm via corresponding characteristic maps, whereby the axle load is determined either by additional sensors (not shown) or by the tire pressures already present via the pressure sensors 27 and specified to the electronic control unit.

Claims

[1] Agricultural vehicle with an electro-pneumatic tire pressure control system (16), wherein the tire pressure control system (16) comprises an electronic control unit (22) for controlling a tire pressure and means for determining or indicating the slip between the ground (11) and the tires (18, 20) of the vehicle (10), wherein a mathematical equation or a map (50) is stored in the electronic control unit (22) and the control of the tire pressure is carried out on the basis of the mathematical equation or the map (50) depending on the slip, characterized by , that the control unit (22) adapts the mathematical equation or the map (50) according to parameters relating to a tire type, a soil type, a soil condition and / or a driving speed, so that, depending on the parameters stored in the mathematical equation or in the map, an optimal slip is achieved for the efficiency of the tire-soil contact. [2] Agricultural vehicle according to claim 1, characterized by that the means for determining or indicating slippage include a radar sensor (38). [3] Agricultural vehicle according to claim 1 or 2, characterized by , that the means of determining or indicating the slippage shall include a positioning system (36) (GPS). [4] Agricultural vehicle according to any one of claims 1 to 3, characterized by that the means for determining or indicating the slippage include an input device (32). [5] Agricultural vehicle according to any one of claims 1 to 4, characterized by , that means (44, 27) are provided for determining the driving speed or the axle load and that the tire pressure can be adjusted depending on the driving speed or the axle load.

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