Agricultural work vehicle

Abstract

The invention relates to an agricultural work vehicle with a cooling device for waste heat cooling, comprising a guide assembly arranged between an engine compartment and a radiator compartment.

Description

[0001] The invention relates to an agricultural work vehicle with a cooling device for waste heat cooling, comprising a guide assembly arranged between an engine compartment and a cooler compartment, wherein an internal combustion engine for driving the work vehicle is arranged in the engine compartment and first air conveying means for generating a cooling airflow are arranged in the cooler compartment and wherein the guide assembly deflects the cooling airflow in radial directions with respect to an axis of rotation of the first air conveying means to generate a negative pressure in the region of the axis of rotation in order to effect an airflow from the engine compartment into the cooler compartment via an intake opening in the guide assembly in the region of the axis of rotation and second air conveying means for conveying ambient air into the engine compartment.

[0002] Such a cooling device in a motor-driven vehicle is described in DE 60 2005 005 148 T2. It comprises a fan that is rotated by an electric motor to blow cooling air drawn from an engine compartment to a radiator. Furthermore, an inlet opening is provided through which cold air from the outside environment can be drawn in by the fan and thus mixed with the cooling air.

[0003] As a result of various development trends in engine design for agricultural vehicles, such as tractors, increased under-hood temperatures have become an undesirable side effect. These trends include the use of exhaust aftertreatment systems due to stricter emissions regulations, as well as the use of charge air turbocharging to increase performance. In the case of exhaust aftertreatment systems, the exhaust gas recirculation cooler, among other components, and ultimately the placement of system components under the hood, such as the particulate filter, and in the case of charge air turbocharging, the necessary charge air cooling, all contribute to an increase in under-hood temperature.

[0004] In the generally prevailing arrangement of the cooling system components in the direction of travel, in front of the combustion engine, the ambient air used as cooling airflow is drawn into the engine compartment at the front of the vehicle. It first flows through the cooling system components before being directed along the combustion engine and released into the environment as warmed or even heated cooling airflow in an area in front of the driver's cab. This regularly exposes the driver's cab to considerable heat stress. The same applies to various electronic components and plastic parts of the combustion engine, which are subject to accelerated aging as a result.

[0005] WO 2009 / 096929 A1 proposes a deflector assembly positioned between the cooling system components and the internal combustion engine. This assembly deflects the cooling airflow passing through the cooling system components in radial directions, preventing it from flowing through the part of the engine compartment where the internal combustion engine is located. By appropriately designing the deflector assembly, low-pressure areas are created in its radially outer regions, drawing airflow from the engine compartment into these areas.

[0006] Based on this, the object of the present invention is to provide a further improved cooling device for waste heat cooling of an aggregate room.

[0007] The problem is solved by an agricultural work vehicle with a cooling device for waste heat cooling, comprising a guide assembly arranged between an engine compartment and a cooling compartment, wherein an internal combustion engine for driving the work vehicle is arranged in the engine compartment and first air conveying means for generating a cooling airflow are arranged in the cooling compartment, and wherein the guide assembly deflects the cooling airflow in radial directions with respect to an axis of rotation of the first air conveying means to generate a negative pressure in the region of the axis of rotation in order to effect an airflow from the engine compartment into the cooling compartment via an intake opening in the guide assembly in the region of the axis of rotation, and second air conveying means for conveying ambient air into the engine compartment. The second air conveying means is an electrically or hydraulically driven cooling fan.

[0008] This inventive design of a cooling device first ensures active and therefore supportive ventilation of the engine compartment. Furthermore, it ensures defined and, if necessary, filtered ventilation of the engine compartment, thereby also preventing ambient air from entering the engine compartment at unwanted points. Additionally, the second air conveying device can provide continued cooling of the engine compartment and, to a certain extent, also of the radiator after the combustion engine has been switched off. Due to the fact that the cooling fan is electrically or hydraulically driven, thermostat-controlled speed regulation can be easily implemented.

[0009] Preferably, the engine compartment and the radiator compartment are enclosed by an engine compartment cover, with the second air conveying means being arranged above the engine compartment in a rear area of ​​the engine compartment cover. This ensures that the cooling airflow is directed into the rear area of ​​the engine compartment, where the highest temperatures regularly prevail.

[0010] In one possible embodiment, a heat exchanger of an internal combustion engine cooling system may be arranged directly downstream or upstream of the second air conveying element. Preferably, this is the heat exchanger of a pre-cooling stage of a two-stage charge air cooling system.

[0011] Preferably, a filter insert for cleaning the intake air is arranged upstream of the second air conveying device. This ensures that no heavily contaminated ambient air is directed into the engine compartment.

[0012] Preferably, the axis of rotation of the first air conveying element is aligned parallel to a longitudinal axis of the work vehicle, with the guide assembly being aligned as far as possible at right angles to the axis of rotation. This ensures the most uniform possible deflection of the cooling airflow in radial directions.

[0013] The cooling device according to the invention is described with reference to the following figure. The figure shows an agricultural work vehicle 12, depicted only schematically in some parts, with a cooling device 10 arranged in a front section for waste heat cooling. The agricultural work vehicle 12 comprises a cab 14, a front axle 16, and an internal combustion engine 20 for driving a rear axle 22. A frame 24 serves as a supporting element for the individual components of the work vehicle 12.

[0014] To dissipate the heat generated during the operation of the internal combustion engine 20, an engine cooling circuit 26 is provided. This circuit comprises a heat exchanger 28 through which coolant flows and which is supplied with a cooling airflow, an oil cooler 30 supplied with the cooling airflow, and a first air conveying means 32 that generates the cooling airflow. This first air conveying means 32 is in the form of a cooling fan, which is driven by the internal combustion engine 20 about a rotary axis D, either permanently or as needed via a viscous coupling. The cooling airflow is schematically represented in the figure by arrows. The cooling airflow can enter the engine compartment 38 through a radiator grille 36 attached to the front of an engine compartment cover 34 of the work vehicle 12. Alternatively, the cooling fan 32 can be equipped with an electric drive motor. Furthermore, a condenser cooler 40 of an air conditioning system can be arranged upstream of the heat exchanger 28 with respect to the cooling airflow.

[0015] A guide assembly 50, acting as a diffuser, is arranged between the internal combustion engine 20 in the rear section of the engine compartment 38, which can therefore be referred to as engine compartment 42, and the components of the engine cooling circuit 26 in the front section of the engine compartment 38, which can therefore be referred to as radiator compartment 44. The guide assembly 50 is preferably oriented vertically with respect to the longitudinal axis of the vehicle. The guide assembly 50 has an intake opening 52 in a central area. Its function is explained below. At least one exhaust opening 54 is provided in the engine compartment cover 34 between the cooling fan 32 and the guide assembly 50 in a radially outer area with respect to the axis of rotation D.

[0016] Furthermore, in the engine compartment 42, a second air conveying device 56 in the form of an auxiliary cooling fan is provided in an upper area of ​​the engine compartment cover 34. This fan can draw ambient air into the engine compartment 42 through an intake opening 58 in the engine compartment cover 34. Simultaneously, as shown, a heat exchanger 60 can be connected upstream of the auxiliary cooling fan 56. The heat exchanger 60 can be associated with a charge air cooling system for the internal combustion engine 20. In particular, it can be a so-called pre-cooling stage of the charge air cooling system, which receives the charge air to be cooled from the compressor stage of an exhaust gas turbocharger and pre-cools the charge air before it is directed to a heat exchanger of a main cooling stage in a front area of ​​the cooling compartment 44.

[0017] The function of the cooling device according to the invention can be described as follows: When the cooling fan 32 is operated, ambient air is initially drawn through the heat exchangers 28, 30, 40, which are arranged in the direction of travel in front of the cooling fan 32, to form a cooling airflow. The cooling airflow is deflected radially outwards by the guide assembly 50 with respect to the axis of rotation D, so that it can escape into the environment through the at least one exhaust opening 54. This radial deflection of the cooling airflow creates a negative pressure in the area of ​​the hub 62 of the cooling fan 32, which exerts a suction effect on the intake opening 52. This suction effect draws air from the engine compartment 42 into the area of ​​negative pressure and also releases it into the environment through the at least one exhaust opening 54.The auxiliary cooling fan 56 assists the airflow from the engine compartment 42 through the intake opening 52 into the cooling airflow delivered radially outwards by the cooling fan 32. Additionally, the operation of the auxiliary cooling fan 56 ensures that positive pressure is maintained in the engine compartment 42. This positive pressure is a prerequisite for allowing ambient air to enter the engine compartment 42 only through the intake opening 58 of the auxiliary cooling fan 56. This ambient air can then be cleaned of contaminants by suitable filter media 64 located above the intake opening 58. The auxiliary cooling fan 56 can be electrically or hydraulically driven. By using a fan that operates independently of the combustion engine 20, the fan can continue to run after the combustion engine is switched off. Reference symbol list 10 Cooling device 12 work vehicles 14 cabins 16 front axle 20 internal combustion engine 22 Rear axle 24 frames 26 Engine cooling circuit 28 heat exchangers 30 oil coolers 32 Cooling fan 34 Engine compartment cover 36 Radiator mask 38 Aggregate room 40 condenser coolers 42 Engine compartment 44 Cooling compartment 50 Tail assembly 52 Intake opening 54 Exhaust opening 56 Additional cooling fan 58 Intake opening 60 heat exchangers 62 hub 64 filter inserts

Claims

[1] Agricultural work vehicle with a cooling device (10) for waste heat cooling, comprising a guide assembly (50) arranged between an engine compartment (42) and a cooler compartment (44), wherein an internal combustion engine (20) for driving the work vehicle (12) is arranged in the engine compartment (42) and first air conveying means (32) for generating a cooling air flow are arranged in the cooler compartment (44) and wherein the guide assembly (50) deflects the cooling air flow in radial directions with respect to an axis of rotation (D) of the first air conveying means (32) to generate a negative pressure in the region of the axis of rotation (D) in order to cause an air flow from the engine compartment (42) into the cooler compartment (44) via an intake opening (52) in the guide assembly (50) in the region of the axis of rotation (D) and second air conveying means (56) for conveying ambient air into the engine compartment (42), characterized by, that the second air conveying means (56) is an electrically or hydraulically driven cooling fan. [2] Agricultural work vehicle according to claim 1, characterized by , that the engine compartment (42) and the radiator compartment (44) are enclosed by an engine compartment cover (34), wherein the second air conveying means (56) are arranged above the engine compartment (42) in a rear area of ​​the engine compartment cover (34). [3] Agricultural work vehicle according to claim 1 or 2, characterized by , that a heat exchanger (60) of a cooling system of the internal combustion engine is arranged immediately downstream or upstream of the second air conveying means (56). [4] Agricultural work vehicle according to claim 3, characterized by , that the heat exchanger (60) is an intercooler. [5] Agricultural work vehicle according to any one of claims 1 to 4, characterized by, that upstream of the second air conveying means (56) a filter insert (64) is arranged for cleaning the intake ambient air. [6] Agricultural work vehicle according to any one of claims 1 to 5, characterized by , that the axis of rotation (D) of the first air conveying means (32) is aligned parallel to a longitudinal axis of the working vehicle (12), wherein the guide assembly (50) is aligned as far as possible perpendicular to the axis of rotation (D).

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