Abstract:
A skid steer loader has an engine compartment that is enclosed with walls, and an engine mounted in the engine compartment. The engine has components such as an exhaust manifold and a muffler inside the engine compartment which can get quite hot under certain operating conditions. A radial fan is provided for withdrawing air from the engine compartment and discharging it to ambient conditions to reduce the temperature in the engine compartment. The fan is in a housing that has apertures that directs air under pressure against the exhaust manifold and muffler and other hot components of the engine to reduce the maximum temperature such components reach.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an air handling system for engines, in particular diesel engines, which provide openings in an engine compartment fan housing to direct cooling air onto surfaces of the engine to reduce temperatures from such surfaces. 
     An engine compartment air handling system for a skid steer loader is typically shown in U.S. Pat. No. 4,815,550. Typically, a fan housing is mounted in the engine compartment and has an inlet which will draw air from the engine compartment, and a second inlet which will withdraw air from a heat exchanger compartment. A radial fan is used to withdraw heated air from the connected compartment and then discharge it to atmosphere. A desired fan shroud has the radial fan in the center portions and is a closed housing except for the inlets and outlets. By withdrawing the warm air from the compartment, cool replacement air comes into the engine compartment. 
     SUMMARY OF THE INVENTION 
     The present invention relates to providing a pressurized flow of air onto hot surfaces of an engine to maintain such surfaces at a lowered temperature than they normally would attain without direct application of forced air. Providing openings in the fan housing in a proper location so that the pressurized air in the housing generated by the radial fan that is used will blow air onto the correct surfaces. As part of this, the inlet openings in the engine compartment fan inlet plate are enlarged a desired amount so that there will be adequate airflow through the engine compartment, because the air that is being added from the holes in the fan housing has to be removed as well. This forms a type of partial recirculation. 
     In the prior art, there were automobiles and other vehicles which used a fan which drew air through a radiator, which was then warm air, and discharged it into the engine compartment and through openings in the bottom of the engine compartment or other locations. The present device, which is a skid steer loader, is an off-road vehicle that operates at a lower speed. It is desirable to withdraw heated air from the engine compartment, while cool air is drawn into the compartment from appropriate openings. 
     Usually the incoming air is air from the operator&#39;s compartment, so the flow of air first acts to keep the operator cool. It is in this context that the present invention finds an advantage in that the fan can be used for directing air under pressure onto selected parts of the engine without discharging all of the air from the fan into the engine compartment. The present arrangement of withdrawing heated air from the engine compartment can be continued. 
     The invention relates specifically to skid steer loaders, in its preferred form, but it is applicable to other types of equipment where engines that have hot areas onto which oil may drop are used, and where an evacuating airflow is discharged from the engine compartment with a forced air fan. The housing for the fan is provided with outlet openings that will cause air under pressure to be blown across components of the engine, while limiting the amount of air that is blown into the engine compartment so an adequate airflow is maintained. The limitation in the amount of air passing into the engine compartment will ensure that the engine compartment itself does not become overly warm because an adequate flow of air will be exhausted out. Replacement fresh air will come in through provided openings in the engine compartment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a typical skid steer loader utilizing the arrangement of the present invention; 
     FIG. 2 is a fragmentary schematic sectional view of the loader of FIG. 1 taken from the side opposite that shown in FIG. 1; 
     FIG. 3 is a side view of the rear portion of the loader of FIG. 1 with portions cut away to illustrate the engine and heat exchanger compartments of the vehicle; 
     FIG. 4 is a schematic perspective view of the engine and heat exchanger housing or shroud; 
     FIG. 5 is a top plan view of the fan housing or shroud of the present invention; 
     FIG. 6 is an end view thereof taken along Line  6 — 6  in FIG. 5; 
     FIG. 7 is a side view of the fan housing of FIG. 5 taken on Line  7 — 7  in FIG. 5; 
     FIG. 8 is a fragmentary enlarged view of the center portions of the fan housing illustrating the outlet ports or openings formed according to the present invention; and 
     FIG. 9 is a sectional view taken as on Line  9 — 9  in FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A skid steer loader  10  which incorporates the present invention and forms the preferred vehicle on which the invention is used, is shown generally in FIG. 1 for reference. The loader  10  includes a main frame assembly  16 , that is supported on an axle assembly  14  driving tires  12 . The frame includes a pair of upright masts  20  at the rear, that mount a lift arm assembly  22 , pivotally mounted to the uprights in a conventional manner and operated with linear hydraulic actuators  24 . Bucket  26  can be used at the ends of the lift arms for operation. 
     The uprights  20  are positioned on opposite sides of an engine compartment that is indicated generally at  28 , and includes an openable end gate  30  for access to the engine compartment. A heat exchanger compartment is above the engine compartment as illustrated generally at  24 , the heat exchanger compartment has an inlet grill  32  at the upper side thereof. 
     Referring generally to FIGS. 2 and 3, the engine compartment  28  is illustrated in greater detail, as is the door or gate  30  for the access to the engine compartment. 
     It can be seen that the main frame  16  provides a support for the operators compartment  34 , including an operator&#39;s seat illustrated in dotted lines at  36 . A wall  38  separates the engine compartment  28  from the operator&#39;s compartment  34 , and as is desired, the airflow from the fan for cooling the radiator and other components will direct outgoing air in direction so that it does not enter the operator&#39;s compartment. 
     The engine, as illustrated, a turbo charged diesel engine, is shown at  48  and is mounted in a suitable manner in the engine compartment  28 . The crank shaft of the engine extends crossways to the loader. The crank shaft drives a suitable hydraulic pump for operating the components of the vehicle and propelling the vehicle with hydraulic motors such as that shown at  44 , in a well-known manner to propel the vehicle. Controls are provided in the operator&#39;s compartment. 
     In the present invention, a fan shroud or housing  50  is mounted in the engine compartment  28 , and mounts a radial fan  52  that is driven in a suitable manner, from the engine. As shown in FIG. 3, the drive comprises a belt  54  operating on suitable pulleys through a gear box  55 , to rotate the radial fan  52  about its axis inside the fan housing assembly  50 . This is driven from the crank shaft of the engine  48  through another belt and pulley arrangement shown schematically at  56 . 
     The fan housing  50  is positioned adjacent to the engine  48 , and in particular, has a side wall  58  that is part of the scroll-shaped housing (see FIG. 5) that is adjacent to components of the engine, such as the exhaust manifold  62 , the muffler  64 , and other components such as an exhaust gas driven turbo charger  63  can get quite hot during operation. The exhaust pipe  65  leads from the turbo charger to the muffler. 
     The fan housing  50  is mounted against a heat exchanger compartment shown in FIG. 2 at  66 , and the heat exchanger compartment is formed by an enclosed wall  68  that houses a radiator  70  and an oil cooler  72  of the skid steer loader. The radiator  70  cools coolant for the engine  48 , and the oil cooler  72  provides cooling of hydraulic oil that is used for operation of a skid steer loader. Hoses connect these components to the engine and the hydraulic reservoir, respectively. 
     In order to provide cooling, it is desired that a flow of cool air pass over the oil cooler  72  and radiator  70  through the inlet opening  32 . The housing  68  is enclosed, except for the inlet opening, and an opening in the lower side, as shown in FIG. 2, which aligns with an inlet opening  74  to the fan housing  50 . This is directly above the fan  52 , and provides a flow of cooling air into the fan housing  50  and specifically the interior chamber  76  for the fan. 
     The fan housing  50  also includes an inlet opening indicated generally at  78  at the lower side, that has an inlet plate  90  with apertures  92  that open directly into the engine compartment  28 . When the fan  52  is driven, air is taken in from both the top and bottom of the fan housing  50  and discharged out laterally through lateral duct assemblies  80  and  82 , respectively, that extend to opposite sides of the loader. The discharge opening  82 A is shown in FIG. 1 on the side of the skid steer loader. A similar opening  82 B is present on the opposite side of the skid steer loader for providing an outflow of air through these ducts, as indicated by the arrows  84  and  86  in FIG.  4 . 
     The radial fan  52  is mounted for rotation within a central portion  88  of the fan shroud or housing  50 , adjacent to and between the air intake openings  74  and  78 . The radial fan  52  preferably is a double-bladed fan that will provide adequate airflow into the fan housing from both the engine compartment and the heat exchanger compartment. 
     The fan inlet plate  90  leading from the engine compartment has the suitably sized apertures  92  to provide for controlling or regulating the amount of air removed from the engine compartment. These apertures  92 , as will be explained, are larger than in a conventional arrangement such as that shown in U.S. Pat. No. 4,815,550. 
     The ducts  80  and  82  depend from the central portion  88 , and have relatively large openings for permitting the discharge or air without substantial restriction once it has been taken into the fan housing by the radial fan  52 . 
     In the present invention, the central housing portion  82  has the scroll-shaped wall  58  that faces the engine  28 , and the hot components such as the exhaust manifold  62 , turbo charger  63 , exhaust pipe  65 , muffler  64 , and other hot engine components. Wall  58  has a plurality of outward airflow apertures  98  formed therein, at a level, and at locations on the wall such that air flowing out of these apertures will be directed toward the hot components of the engine  48  to cool the extremely hot components the flow is indicated at  93  in FIG.  4 . As can be seen in FIG. 9, the spacing between the apertures shown generally at  98 , such as the individual apertures  98 A,  98 B,  98 C,  98 D,  98 E and  98 F can be varied so that the airflow volume is controlled but yet the airflow is directed at the areas and components which become the hottest on the engine  48 . 
     The inlet apertures  92  are enlarged to ensure that there is an adequate airflow out of the engine compartment  28  through the fan housing  50  and specifically the central portion  88 , and then out the duct ends  80  and  82  for discharge to the atmosphere while taking into account the recirculation or addition of air into the engine compartment through the apertures  98  in the wall  94 . 
     The balancing of the flow can thus be achieved, and the size of fan  52  does not have to be radically altered. 
     FIG. 6 shows an end view of one of the ducts and it can be seen that the ducts are shaped so that they are about the same size as the axial or vertical height of the center portion  88 , near the fan and they enlarge in vertical direction so that the opening  82 A, for example, is of substantial size. Suitable connecting fittings can be made for mounting the fan in place, which are explained more fully in U.S. Pat. No. 4,815,550. 
     Again, the engine compartment is closed except for the inlet openings that are provided for fresh airflow, such as through the wall  38  leading to the operator&#39;s compartment to provide airflow out of the operator&#39;s compartment, or through suitable apertures in the bottom of the engine compartment. The fan  52  is of size so that it will provide airflow through both the engine compartment and the heat exchanger compartments  66 . Heat exchanger compartment wall  68 , as shown, forms an enclosure except for the inlet  32  so that the cool air will flow across the radiator  70  and the oil cooler  72  into the housing compartment  76  in the central portion  88  of the fan shroud. 
     The amount of air that is discharged onto the hot components or surfaces of the engine will be sufficient to keep the temperature down on the hot components to a level that will help increase engine life. Evaporation of hydraulic oil contacting the components cooled by the supplemental air flow will be probably in the form of a smoke, which will be discharged out through the sides of the engine compartment through the ducts  80  and  82 . 
     The invention has particular applicability for turbo charged engines, since the turbo charger gets quite hot from the exhaust gases running it. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.