Windrower tractor with parallel heat exchangers for cooling of engine and associated fluids

An agricultural tractor having its engine longitudinally spaced along its frame from the operator cabin features at least two heat exchangers carried on the frame at a position located longitudinally between the operator cabin and the engine to perform air-cooling of at least one fluid associated with the engine. The two heat exchangers are arranged in parallel so as to each accept an intake stream of ambient air that is independent of a discharge stream of exhaust air from the other heat exchanger. Accordingly, each heat exchanger uses the coolest air possible to maximize the cooling potential of the system. The discharge stream of air from the heat exchangers is exhausted rearward to avoid recirculation of this heated air as the machine moves forward, and to direct the exhaust air past the engine for further cooling effect.

FIELD OF THE INVENTION

The present invention relates generally to cooling systems for windrower or swather tractors, and more particularly to an improved cooling system employing heat exchangers positioned between the operator cab and engine in a configuration employing parallel ambient air inlets to minimize the intake air temperature of each heat exchanger for maximum heat transfer.

BACKGROUND OF THE INVENTION

Stringent emission standards have increased the heat rejection requirements of diesel engine cooling systems. As a result more efficient means of cooling these engines are required. Windrowers operate in high crop debris conditions that foul cooling systems. Increasing the cooling requirements requires more air flow through the coolers, which results in either higher velocity air given the same area, or larger cooler face with equal or reduced air velocities. Historically the cooling system in windrowers had the heat exchangers set up in series, i.e. with the discharging air stream from one heat exchanger forming the inlet air stream of a next heat exchanger, significantly reducing their overall efficiency. The most efficient heat exchanger has a large frontal surface area and a thin core exposed to ambient air.

John Deere, New Holland and the current production MacDon Windrower all use similar systems that draw the cooling system air in at the rear of the machine, through a series of heat exchangers, exhausting the hot air into the direction of travel in which the machine is driven while operating in the field (heavy loading so where cooling requirements are the highest. Such conventional arrangement is schematically illustrated inFIG. 1, where a windrower tractor1is being driven in a forward working direction F, in which the header23A of the windrower1leads a frame11on which the operator cabin30, engine24, and heat exchangers50a,50bare carried. The engine24lies between the operator cab30and the heat exchangers50a,50b, which are mounted one behind the other at the rear of the tractor frame. The rearmost mounted heat exchanger50adraws ambient air52in from behind the tractor for cooling one or more engine associated fluids (e.g. coolant, engine oil, engine charge air), and the air then continues forwardly through the second heat exchanger50bto cool another one or more of the engine associated fluids. The intake air of the second heat exchanger50b, being the same air discharged from the first heat exchanger50a, is thus at a higher temperature than the ambient air used by the first heat exchanger.

This conventional configuration drawing in air for the cooling system at the rear of the machine and exhausting the hot air towards the front of the machine (i.e. in the direction of travel) acts to preheat the air being drawn into the system. That is, the forward discharge of the exhaust54air from the heat exchangers50a,50bcreates an issue in that the forward working direction F of the machine moves the tractor forwardly past freshly exhausted air54, which means that some of this exhaust air54is re-circulated through the heat exchangers, as shown in broken lines at56, thus reducing the inlet air temperature and accordingly reducing the efficiency of the heat exchanger operation.

One known Hesston windrower, shown schematically inFIG. 2, differs from the above configuration, instead having the heat exchangers18a,18bpositioned between the cab14and the engine to draw the ambient air20in behind the cab14on top of the engine hood58, and then discharge the exhaust air22downwardly. However the majority of heat exchangers18a,18bor coolers in this configuration are still arranged in series.

A more recent Hesston design is shown schematically inFIGS. 9 and 10. This design employs parallel heat exchangers arranged in a box like configuration behind the engine, with two heat exchangers50x-1and50x-2facing rearward and two others50y,50zfacing laterally outward. Ambient air52is drawn forwardly and laterally in at the rear of the machine by a fan59that is located opposite the rear heat exchangers50x-1,50x-2and between the two lateral heat exchangers50y,50z, the air thus passing through heat exchangers50x-1,50x-2,50yand50zand then being discharged forwardly towards the engine before exiting laterally and downwardly from the engine compartment. While the use of parallel streams of intake air for the different heat exchangers presents some advantage over more conventional series configurations, the direction of exhaust air discharged from the heat exchangers again creates potential air recirculation paths56that may limit the heat exchange efficiency.

Accordingly, there is desire to provide an improved cooling system for the engine of a windrower or swather tractor.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided an agricultural tractor comprising:

a frame extending in a longitudinal direction the tractor;

a plurality of rotatable ground wheels connected to the frame to convey the frame over the ground, including drive wheels operable to drive the tractor in a forward working direction along the longitudinal direction of the tractor;

an operator cab carried on the frame;

an engine mounted in an engine compartment on the frame at a position longitudinally spaced from the cab in a rearward direction opposite the forward working direction; and

at least two heat exchangers carried on the frame at a position located longitudinally between the operator cab and the engine and operable to perform air-cooling of at least one fluid associated with the engine, each of the two heat exchangers being arranged to accept an intake stream of ambient air that is independent of a discharge stream of exhaust air from the other of the two heat exchangers in the cooling of the least one fluid associated with the engine; and

an exhaust air outlet configuration arranged to direct the discharge stream of air from each of the two heat exchangers in an exhaust direction having no forward component in the longitudinal direction.

Preferably the exhaust air outlet configuration is arranged to the direct the discharge stream of air from each of the two heat exchangers in the rearward direction.

Preferably the exhaust air outlet configuration is arranged to direct the discharge stream of air from each of the two heat exchangers past the engine.

Preferably the heat exchangers are arranged to have the intake stream of ambient air pass therethrough in a transverse direction crossing the longitudinal direction.

Preferably ambient air inlets through which the intake streams of ambient air enter the two heat exchanges are spaced apart from one another.

The ambient air inlets may be situated on opposite sides of a longitudinal center-line of the frame. Alternatively, the ambient air inlets may be in a central position on the longitudinal center-line of the frame positioned, for example overhead of the heat exchangers.

Openings of the ambient air inlets may face laterally outward to accept ambient air from respective sources on opposing sides of the tractor.

Alternatively, openings of the ambient air inlets face upward to accept ambient air from above the tractor. Another embodiment may employ combinations of laterally and upwardly opening ambient air inlets.

Preferably the two heat exchangers are arranged for air to flow through the heat exchangers into a central space therebetween.

There may be provided a housing enclosing the central space between the heat exchangers and a fan mounted to the housing to convey air through the heat exchangers into the housing, and then longitudinally rearward through the exhaust air outlet configuration.

Alternatively, there may be provided a respective fan for each of the two heat exchangers and air flow guides disposed in the space between the two heat exchangers, the fans being operable to convey air through the heat exchangers into the space therebetween, where the air flow guides then redirect the air longitudinally rearward. These fans may be driven independently or by a common shaft.

Preferably each fan is a variable speed fan.

There may be provided a fan controller operable to change an operating speed of the fan according to conditions monitored by said controller.

The one or more conditions monitored by said controller may include ambient air conditions.

Additionally or alternatively, the one or more conditions monitored by said controller may include engine load conditions, engine coolant, charge air or hydraulic oil cooler temperature.

Preferably each fan is a reversible fan operable in a heat exchange mode rotating in a first direction to convey ambient air inward through the heat exchangers from a surrounding environment, and a clean out mode rotating in an opposite direction to convey air outward through the heat exchangers into the surrounding environment to dislodge contaminants clogging intake areas of the heat exchangers.

Each fan may be hydraulically powered.

Instead of, or in addition to, one or more reversible fans, known types of self-cleaning screens may be incorporated into flow paths of the intake streams of ambient air to reduce restriction of the air flow caused by buildup of debris.

DETAILED DESCRIPTION

With reference toFIG. 4, a swather tractor generally indicated at10includes a frame11which is carried on a first pair of driven ground wheels12and13and on a second pair of non-driven castor wheels14and15. The driven wheels12and13are mounted on suitable supports16which support the ground wheels from the frame11. The driven ground wheels12and13are each driven by a hydraulic motor17carried on the support16which receives hydraulic fluid under pressure from a supply line and drives the ground wheel at a rate of rotation dependant upon the rate of flow of the hydraulic fluid.

The wheels14and15are mounted on conventional castors18which swivel about a castor pin19. The ground wheels14and15are non driven and are simply mounted in a supporting bracket20which can pivot around the castor pin19so that the castor wheels follow the movement of the vehicle as controlled by the driven wheels12and13. Thus the speed of the vehicle over the ground is controlled by the rate of rotation of the wheels12and13and steering is controlled by a differential in speed between the wheels12and13.

The frame is shown only schematically since this can vary widely in accordance with requirements, as is well known to a person skilled in this art. At the driven end11A of the frame is mounted suitable supports21and22for carrying a header23A. Again these elements are well known to persons skilled in this art and various different designs can be used. Thus the support elements21,22on the header carried thereby are shown only schematically. Various different types of headers can be used including disc type cutters or sickle knife cutters. The width of the header can vary considerably depending upon the type of crop and the cutting system employed. The header is preferably carried on the tractor rather than on separate supports and the tractor includes a lifting mechanism schematically indicated at23operable to raise and lower the header on the tractor between different working positions, and between working positions and a raised position cleared from the ground for moving the header over the ground when not in working position.

The tractor includes an engine24carried on the frame11adjacent a second end11B of the frame. The engine is arranged to drive a series of pumps25,26and27for generating pressurized hydraulic fluid for driving the various components of the tractor. Separate pumps can be used as shown or single pump can be used with the hydraulic fluid under pressure generated thereby being separated into separate controlled fluid paths for operating the various components, or in a parallel arrangement such as on the M-series windrowers manufactured by the present assignee.

At the driven end11A of the frame is provided a cab30which sits over the driven end between the driven wheels12and13so the operator can look over the header23A during the operating action on the field. The cab30encloses an operator console generally indicated at31which includes a seat32, a steering control33such as a conventional steering wheel, a speed control34and an accessory control35. The steering wheel33is of a conventional nature and is mounted in the console in front of the seat by suitable mounting arrangements which allow the operator to enter the seat and be comfortably located on the seat behind the steering wheel. To the right hand of the operator is provided a speed control34generally in the form of a lever which can pivot forwardly and rearwardly between a reverse position at the rear, a neutral position at the center and a forward position at the front. In an intuitive manner, therefore, the operator can pull rearwardly on the lever for reverse and push forwardly on the lever for forward movement, with the rate of the movement being controlled by the relative position of the lever along its sliding action. In addition there is provided a switch34A which can be operated to select speed ranges for the driving speed of the vehicle.

To the right hand of the operator, on the same lever as the speed control for convenient access to the operator's hand, is provided the accessory control35which includes a series of switches and levers for operating the position and operating parameters of the header attached to the tractor. The switches may include a header height and angle control by way of a four way (two axis) switch, a reel height and forward location control by way of a four way (two axis) switch and a reel speed control two way one axis switch so that the skilled operator can control the parameters of the header during the working action. The header is engaged by a main drive control lever in many cases also be reversed in the event of a blockage and thus will include a switch for allowing such reversal.

Many of the above components are well known and conventional and can be found in many different designs of such tractors manufactured by a number of manufacturers including the present assignee.

The operator console31may be of the type described in U.S. Pat. No. 7,159,687 of the present assignee, where the console is arranged to be rotatable about an upright axis between a first position (illustrated inFIG. 4) where the seat faces the driven end11A of the machine and a second position (not shown) in which the seat faces the engine end11B of the machine. The first of these positions is known herein as a “field” or “cab forward” mode where the operator console faces the header23A for use of the same in the field with the machine driven in the illustrated working direction F. The other position may be known as a “transport” or “engine forward” mode, where the operator console faces the engine end11B of the machine for road transport of the machine by driving of same in an opposite direction in which engine leads the cab. As the present invention is concerned primarily with the operation of the tractor's cooling system in the field mode, where both the header and drive system present loading on the engine as compared to transport mode where the header is not used, the terms front/forward and rear/back/rearward are used in relation to the forward working direction F shown in the drawings, where the header end11A of the frame11and the cab30mounted at this end of the frame lead the engine in this direction, and thus define the forward end of the machine.

With reference toFIGS. 3 and 4, where the swather tractor10of the present invention differs most notably from the prior art tractors ofFIGS. 1 and 2is in the positioning of its two heat exchangers50c,50dbetween the cab30and the engine24in a configuration acting to provide each heat exchanger50c,50dwith a respective stream of ambient intake air52a,52bthat is drawn in behind the cab30and is separate and independent of the exhaust air stream54a,54bof the other heat exchanger, which is directed rearward along the longitudinal axis L of the machine, past the engine24and out the rear end of the engine hood at the rear end of the frame. The use of the term independent to describe the relationship between the intake air stream flowing into each heat exchanger and the exhaust stream exiting the other heat exchanger is used to mean that the intake air of each heat exchanger is free of any exhaust air from the other exchanger. The ‘term’ independent does not necessarily dictate that the airflows moving through the heat exchangers remain separate (free of one another) in their entire travel through the machine, as for example, the exhaust air from the two heat exchangers may mix together after having passed through the heat exchangers.

The two heat exchangers may be multi-fluid heat exchangers, each providing air cooling of two or more fluids. The two heat exchangers may provide a total of four heat exchange relationships, for example in the form of an oil cooler, an AC condenser cooler, an engine radiator and an a charge-air cooler, with an optional fuel cooler providing a fifth heat exchange relationship.

In the illustrated embodiments, the two cross-flow heat exchangers50c,50dare spaced apart on opposite respective sides of a longitudinal center line L of the frame11, with the cross-sectional area of each heat exchanger52c,52d(i.e. the plane of the heat exchanger that is perpendicular to the general direction of airflow through it) arranged to lie more parallel than perpendicular to the longitudinal direction of the frame11, with the cross-sectional area facing laterally way from the center line L of the frame. One or more fans are operable to draw air inwardly through the heat exchangers into the central space left there between, where the air is redirected to travel rearward along the center line L of the frame, past the engine24, and the hydraulic pumps25,26,27and any other engine-driven accessories24a(alternative, air conditioning compressor, etc.) for exit through the rear end of the hood that encloses the engine compartment.

In the heat exchanger assembly ofFIGS. 3 and 5, each heat exchanger50c,50dis mounted to an outer face of a respective fan housing60located on a respective side of the center line L of the frame11. An opposing inner face60aof the fan housing60faces toward the center line L of the tractor frame11and features a pair of motor-mounting rails62spanning across a circular opening through the fan housing60in order carry a hydraulic motor64of the fan66that is rotatably supported in the circular opening of the housing60for driven rotation by the output shaft of the hydraulic motor64. Airflow guides or deflectors68are positioned between, and may join together, the fan housings60of the heat exchangers. Each airflow guide features an upright front wall68aprojecting inwardly from the respective fan housing in front of the fan opening, and curving through ninety degrees about an upright axis. A central upright divider68bthen runs linearly rearward along the center line L of the tractor frame11past the fan openings from the curved front walls68aof the airflow guides68, and may be defined by a single central wall shared by the two airflow guides, or by face-to-face walls of the two airflow guides. In the illustrated embodiment, each airglow guide68is completed by a top wall68cjutting outward from the fan housing over the fan opening therein to the central divider. The top walls may have separate walls or may be integrally defined by a common top wall spanning fully between the two fan housings.

Under rotation of each fan66in a predetermined direction by its respective hydraulic motor64, for example under rotation of the two fans in the same direction with fan blades of opposite pitch, the fans draw air through the respective heat exchangers into the space therebetween, where the airflow guides then redirect the exhaust airflow from the heat exchangers rearwardly through the engine hood58′ of the tractor. Each hydraulic fan is reversible, whereby operation of the fans in the opposite direction will blow air backward through the heat exchangers from the space therebetween in order to loosen particulate or debris that has become lodged within the heat exchanger. Operation of the fans in the first direction thus defines a heat exchange mode of fan operation in which ambient air from outside the engine hood is drawn laterally thereinto through each heat exchanger, thereby cooling the one or more engine associated fluids circulating through conduits of the cross-flow heat exchanger. Operation of the fans in the second direction defines a cleanout mode, forcing air in the reverse direction from inside the engine hood out into the exterior environment.

Each heat exchanger may be operable to perform cooling of one or more fluids associated with the engine24. For example as shown inFIGS. 3 and 5the first heat exchanger50c, situated adjacent the left side of the tractor when installed, may be a combined oil cooler and air conditioning condenser cooler. The second heat exchanger50dat the right of the figure may feature an engine radiator having engine coolant inlet and outlet ports and a pressure cap, and also feature a charge-air cooler for cooling the compressed air from a turbocharger on its way to the engine for use in the combustion process. This is only an example of one possible configuration, and it will be appreciated that the number and type of fluids cooled by each heat exchanger, and the distribution of these fluids among the two heat exchangers may be varied, while still benefiting from the present invention's use of parallel airflows through the two heat exchangers to gain the advantage of low temperature ambient air at each one. In addition to the parallel heat exchangers, a small additional heat exchanger (e.g. fuel cooler) could be added in series if space limits or other constraints warrant or demand such a configuration without significant adverse effects of the achieved advantage of the lower-temperature inlet air for the parallel heat exchangers compared to the prior art series designs.

FIG. 6shows a second embodiment configuration of parallel heat exchangers. Again, each of the two heat exchangers50c,50dis disposed on a respective side of a central space left therebetween so as to reside on a respective side of the tractor's longitudinal center line L, but rather than being respectively mounted on two separate fan housings, the heat exchangers are mounted on the laterally outer side walls of a larger single fan housing60′ that encloses the space between the two heat exchangers. Instead of two fans having rotational axes lying transverse to the longitudinal center line of the tractor, a single fan66′ is supported in a sole opening of the fan housing60′ in the rear wall74thereof for driven rotation about a generally horizontal axis parallel to the longitudinal direction of the tractor frame11. Again, the fan may be hydraulically powered and reversible for operation in both heat exchange mode and cleanout mode. In heat exchange mode, the fan draws air through the heat exchangers into the space therebetween, then blows the air rearwardly out of the fan housing to pass by the engine, and possibly engine-driven pumps and accessories depending on the engine compartment layout, for exit from the engine compartment through suitable openings in the rear wall of the engine hood. In one embodiment, the heat exchanger assembly shown inFIG. 6may be mounted atop the hydraulic pumps, in which case the existing air flow will not directly flow over the pumps. For example, a six-cylinder engine model may have such a configuration where the pumps lie below the heat exchanger assembly, while a four cylinder model may have the pump situated behind the heat exchanger assembly, where they may be exposed to flow of discharge air from the heat exchangers. Some of the air discharged rearwardly from the heat exchangers air may move downward and exit the machine below the engine compartment.

TheFIG. 6embodiment also differs from that ofFIG. 5in the addition of inlet ducts76defined at the outer faces of the heat exchangers. Each inlet duct has front and rear walls76a,76bprojecting laterally outward from the heat exchanger, and an outer wall76cinterconnecting the front and rear duct walls at distal ends thereof opposite the heat exchanger. The front and rear walls are tapered in width, each narrowing from its top end to a bottom point, whereby the outer wall76cis obliquely sloped relative to the outer face of the heat exchanger. The duct is open at a top end thereof to create an inlet opening76dbound by the tops end of the duct walls and the top end of the outer face of the heat exchanger. Due to the tapered front and rear walls and sloped outer wall, the duct is therefore also tapered to grow smaller moving from its open top end to its closed lower end at the bottom of the heat exchanger.

Still referring to theFIG. 6embodiment, each heat exchanger is obliquely tilted about a horizontal axis out of a vertical orientation by approximately 20 degrees to lean its upper end inwardly toward the central longitudinal axis L of the machine, thus making room for the tapered inlet ducts that are wider at their upper inlet ends without increasing the width of the overall heat exchanger assembly. Each heat exchanger is also tilted obliquely about vertical axes to deviate from a from an orientation parallel to the longitudinal axis L of the machine so that the two heat exchangers lie in planes that horizontally diverge toward the rear end of the machine. This rearward divergence of the heat exchangers improves air flow inside of the housing60′ in that the two streams of exhaust air converge better, thereby reducing turbulence and as a result increasing overall efficiency. In addition, this configuration reduces the width of the overall heat exchanger assembly near the rear of the operator cabin, which allows for improved visibly of the caster wheels14,15from the operator cabin, and also reduces the overall space taken up by the assembly.

The first embodiment ofFIG. 5lacks such inlet ducts, instead leaving the laterally outward facing sides of the heat exchangers exposed to communicate with the ambient environment outside the engine hood through suitably screened openings78in the sides of the engine hood58′ (FIG. 7) near the front end of the hood that resides behind the cab when the hood is in the closed position. In the second embodiment, the engine hood58″ (FIG. 8) features openings80in the top wall thereof at respective positions adjacent the sides of the hood to fluidly communicate the outside environment with the inlet openings76dof the inlet ducts, which underlie the openings of the hood when the heat exchanger assembly is installed and the hood is closed. In the illustrated embodiment ofFIG. 8, the inlet openings80in the hoods are not screened. Instead, a screen for each heat exchanger is found within the respective inlet duct76in an orientation lying parallel to the heat exchanger to maximize the screen area and thereby increase the length of time for debris to built up to level sufficient that will significantly restrict airflow.

In addition to these different positions of the air inlet openings in the hood,FIGS. 7 and 8also schematically illustrated a screened or other arrangement of airflow openings82at the upright rear end of the hood so that the exhaust air being discharged rearwardly from the heat exchanger assembly inside the engine hood can exit the rear of the engine compartment after flowing past the engine and the engine driven pumps and accessories. As shown inFIGS. 3 and 4, the fuel tank84of the tractor is mounted externally of the engine hood at a lateral position at a respective side of the frame11so as not to form an obstruction to exhaust air flowing rearwardly through the engine compartment for exit through the rear end of the hood. This rear exhausting of the air from the heat exchangers allows this stream of exhaust air to collect additional heat from the engine and engine driven components inside the hood as it moves rearwardly therepast, thereby further improving the overall cooling functionality of the system.

With the engine oriented to place the bell housing of the engine and large hydraulic pumps25,26,27driven thereby at the front end of the engine, thus placing the smaller collection of other engine driven accessories24aat the opposing rear end of the engine, the engine block can be placed as far rearward as possible on the frame, thereby maximizing a ballast effect of the engine in countering the weight of the header23A carried at the front end of the frame. The positioning of the hydraulic pumps ahead of the engine also reduces the length of the hydraulic lines to the hydraulic wheel and header motors.

In addition to being reversible, the fan or fans of the heat exchanger assembly may have variable speed capability, for example employing fan controller (shown schematically at86inFIG. 4) to automatically adjust the fan speed using one or more sensor inputs to monitor one or more conditions, such as ambient air temperature measured outside the engine hood by exterior temperature sensor88or temperatures or other conditions reflective of engine loading inside the engine hood by interior sensor90. Cooler ambient air temperatures mean a larger difference between the temperature of the cooling air and the engine fluid being cooled, and thus greater heat transfer therebetween, thereby allowing the fan speed to be reduced, which in turn reduces engine loading. High engine loading conditions increase the cooling requirement, and thus detected high-load conditions can be used to increase the fan speed to increase the volumetric flow rate of cooling air through the heat exchangers. Hydraulic fan controllers using electronic sensors to control valves in hydraulic fluid connections are known, and may be employed for automatic fan control in the present invention. Alternatively, other embodiments may employ electric fans in place of powered fans. Further alternate embodiments may employ screen cleaning systems of other types in addition to or in place of the reversible-fan based clean out system.

The described embodiments maximize the area available for all heat exchangers. With all heat exchangers exposed to ambient air, the system is more efficient, reducing the total volume required for heat exchangers. This large area is kept clean by the use of a pre-cleaning screen system and/or reversible fan system, which also allows for the option of reduced fan speed under light load conditions and/or low ambient temperature conditions to conserve power. The heat exchangers are located directly behind the cab, at which location the fresh air is drawn in. All of the heat exchangers are arranged in parallel, maximizing their heat transfer potential. The hot air is exhaust out the back of the machine, in the opposite direction of travel while operating the machine under load in the field.

Large surface area maximizes heat exchanger efficiency, minimizing the size of the heat exchanger. Large surface area allows reduction of core thickness, reducing the fan power required to move the volume of air required by the heat exchanger. With all coolers exposed to ambient air, the temperature differential between the cooling fluid and the fluid being cooled is greater, and as a result, efficiency is increased, allowing reduction of the cooler size. Large surface area reduces the cooling system's fresh air intake velocity, thereby reducing debris accumulation. Variable speed fans can be used to only supply the amount of air that is required to cool the system, reducing total fan power consumption. Air is drawn in at the longitudinal center of the machine just behind the cab, where dust and debris created by drive wheels and crop harvesting machines is minimized, while the hot cooling system exhaust air exits at the rear of the machine while operating in the field to minimize or remove possible recirculation of the hot air through the cooling system.

The described positioning of the heat exchangers between the operator cabin and the engine, presents a further advantage if the context of the aforementioned rotatable-console machines where the operator console cab face opposite directions for field/cab-forward and transport/engine-forward modes of operation, as the physical side of the heat exchangers can be increased to provide greater surface for more effective cooling with less detriment to the operators field of view past the engine-end of the machine, thereby minimizing the impact of larger heat exchangers on engine-forward visibility compared to layouts where the heat exchangers lie on the side of the engine opposite the operator cabin.