Abstract:
A modular cooling plant for an internal combustion engine and accessory equipment installed on a motor vehicle provides a joint external frame supporting several heat exchangers and a centrally positioned centrifugal blower. The centrally positioned centrifugal blower is driven by a hydraulic motor through an impeller drive shaft, clutch and impeller. The hydraulic motor and dependent drive assembly are also mounted to the joint external frame to avoid risk of damage to the heat exchangers from the impeller should the vehicle engine shift.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to cooling systems for internal combustion engines and more particularly to a compact cooling system for a truck engine which is relatively immune to damage from accidental shifts in engine position. 
     2. Description of the Problem 
     Some compact cooling systems for medium and heavy duty trucks have arranged a plurality of heat exchangers in a box like configuration. Individual heat exchangers are aligned with the direction of movement of the vehicle, with air drawn into the box from an end opened to the vehicle grill. A multiple-vane centrifugal blower is positioned in the box, rotating on an impeller which is centered in the box and axially aligned longitudinally with the vehicle. The heat exchangers at least partially surround the blower. The heat exchangers have been fixedly mounted to the frame of the vehicle. 
     The impeller has been driven by an impeller drive shaft which has in turn been driven by an impeller drive pulley attached to the vehicle&#39;s engine. No translation of the impeller drive pulley relative to the engine is possible in this arrangement. Thus, if the engine were to move relative to the heat exchanger, which can happen if an engine mount breaks and the engine moves relative to the frame of the vehicle, the impeller will move relative to the heat exchangers. Under these circumstances a collision between the impeller and one or more of the heat exchangers is possible with a high likelihood of expensive to repair damage to the heat exchanger. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a vehicle having a modular compact engine cooling assembly. The modular compact engine cooling assembly comprises a multiple vane centrifugal blower centered in an arrangement of heat exchangers. An impeller for turning the multiple vane centrifugal blower is centered within the box and blower. An external frame supports the assembly from the frame of the vehicle. A drive motor for the impeller is mounted with respect to the external frame and coupled to the impeller for powering the impeller. The motor is preferably hydraulically pumped. 
     Additional effects, features and advantages will be apparent in the written description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a top plan view of a vehicle chassis; 
     FIG. 2 is a perspective view of the modular cooling plant of the present invention; 
     FIG. 3 is a schematic of the modular cooling plant; 
     FIG. 4 is a top schematic of the modular cooling plant; 
     FIG. 5 is an section view of the modular cooling plant; 
     FIG. 6 is a schematic of an alternative hydraulic motor control system used with the modular cooling plant. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures and in particular to FIG. 1 there is illustrated a vehicle frame  80  comprising left and right side rails  10  and  11  which extend in parallel for the longitudinal length of the frame. Rails  10  and  11  are held in parallel by a plurality of latitudinal cross beams  83  and are supported on front steering axle  88  and rear drive axles  92 . Front wheels  86  and rear wheels  90  support the axles and allow the vehicle to move in directions parallel to the direction of elongation of the frame. Mounted over the front steering axle  88  between side rails  10  and  11  on a plurality of engine mounts (not shown) is a liquid cooled engine  14 . Between engine  14  and the front of the vehicle frame  80  is modular cooling plant  16  supported from the side rails  10  and  11  by external frame rails  18  and  20 , which are mounted on side rails  10  and  11 , possibly vibrationally isolated from the side rails by rubber bushings (not shown). Engine coolant and other fluids circulate between liquid cooled engine  14  and the modular cooling plant  16 . 
     Referring now to FIG. 2, modular cooling plant  16  is shown in perspective as viewed from the left (driver&#39;s side) front corner of the chassis. The heat exchangers  22 ,  24 ,  26  and  28 , blower  32 , fan impeller (shown in FIG.  4 ), impeller drive shaft (shown in FIG. 4) and hydraulic fan motor  40  are assembled as a modular package to be fixedly attached by frame rails  18  and  20  to the front portion of vehicle frame  80 . Modular cooling plant  16  is located between the vehicle&#39;s grill and the front of engine  14 . The axis of rotation of the impeller is parallel to the longitudinal axis of the vehicle. The blower  32  draws air through a vehicle grill or scoop and inlet  30  into a region surrounded on four sides by heat exchangers  22 ,  24 ,  26  and  28 . Air is forced by blower  32  out through the sides of the enclosure formed by heat exchangers  22 ,  24 ,  26  and  28 . Heat exchangers  22 ,  24 ,  26  and  28  may be connected to coolant circulation systems for the engine, air conditioning compressor, automatic transmission, etc. 
     The front of modular cooling plant  16  is partially closed by front panel  36 . Air inlet  30  is defined by an opening through panel  36 . Visible through the opening is a hydraulic motor  40  which drives the rotary squirrel cage  41  of multiple vane centrifugal compressor  32 . Panel  36  is supported in place by connection to braces  35  and  34 , which are mounted on external support rails  20  and  18 , respectively. 
     Modular cooling plant  16  is supported between side rails  18  and  20 , and comprises four heat exchangers  22 ,  24 ,  26  and  28 . Heat exchangers  22 ,  24 ,  26  and  28  are arranged end to end in a trapezoidal shaped enclosure, with top heat exchanger  26  and bottom heat exchanger  28  forming the parallel sides of the enclosure and with side heat exchangers  22  and  24  being canted inwardly toward one another at the bottom of the enclosure. Inside of the enclosure formed by heat exchangers  22 ,  24 ,  26  and  28  is a multiple vane centrifugal blower  32  which is mounted for rotation in the cooling plant  16  as discussed below. 
     Referring to FIG. 3, energy delivery to hydraulic motor  40  is schematically illustrated. Hydraulic motor  40  is located centered within heat exchangers  22 ,  24 ,  26  and  28  its mounting buffered by isolators to reduce vibration transmitted to the heat exchangers. Hydraulic motor  40  receives pressurized hydraulic fluid from power steering pump  54  through a conduit  46 . Fluid is returned from hydraulic motor  40  by a conduit  48  to a power steering fluid reservoir  42 , from which it is drawn for recirculation by pump  54  through tube  52 . 
     Referring to FIG. 4 energy transfer from hydraulic motor  40  to multiple-vane centrifugal blower  32  is depicted. Hydraulic motor  40 , centered in air inlet  30 , is directly coupled to and supported on an end of a rigid impeller drive shaft  58  located in the center of multiple-vane centrifugal blower  32 . Drive shaft  58  rotates in a shaft bearing  62  and is connected into a fan clutch  60 , which couples energization to impeller  56 . Impeller  56  in turn rotates in a fan bearing  64 . Blower vanes  132  are disposed around the radial impeller  56  to provide the multiple-vane centrifugal blower  32 . Fan clutch  60  is mounted in a rear wall  70  of the modular cooling plant  16 . Fan clutch  60  operates conventionally, allowing multiple-vane blower  32  to free wheel when the rate of air flow forced through inlet  30  outstrips the rate at which impeller drive shaft  58  would drive the blower. 
     As seen if FIG. 5, rear wall  70  is mounted between and to side frame rails  18  and  20  making the wall part of the external frame serving to brace the heat exchangers  22 ,  24 ,  26  and  28 . Heat exchangers  22 ,  24 ,  26  and  28  and front wall  36  are further braced on rails  18  and  20  by braces  34  and  35 . 
     Referring now to FIG. 6 a control schematic for an alternative embodiment of the invention is described. A centrifugal blower  232  is directly driven on a shaft  200  from hydraulic motor  140  which is mounted in rear wall  170  of a modular cooling plant  216 . Modular cooling plant  216  comprises a plurality of heat exchangers, including heat exchangers  222  and  224 , arranged radially around centrifugal blower  232 . Hydraulic motor  40  is energized by pressurized hydraulic fluid from a reservoir  42  which is pumped to the motor by pump  54  through conduit  146 , valve  182  and conduit  147 . Valve  182  may be used to vary the flow of fluid under the control of a solenoid  181  which is activated by a solenoid controller  180 . Controller  180  may be a implemented by a thermostat or by some sort of engine controller running a more sophisticated cooling regimen. Controller  180  allows speed control of blower  232  to be implemented. Pump  54  is driven by engine  300 , typically using drive belts between the engine crankshaft and a drive pulley attached to the pump (not shown). 
     The present invention eliminates the possibility of translational movement of the impeller relative to the heat exchangers by mounting both heat exchangers and the impeller to the same supporting sub frame. The use of hydraulic drive for the impeller allows use of simple rigid impeller drive shaft. 
     While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.