US3874347A - Shutter-fan system - Google Patents

Abstract

A vehicle coolant system incorporating a shutter-fan capable of restricting the passage of air through the radiator section of the system until a predetermined coolant temperature at the engine inlet is achieved, the opening of the shutter-fan to an air impelling condition then being effected by a thermally actuated unit exposed to engine coolant at inlet conditions.

Description

United States Patent [1 1 [111 3,874,347 Hovey 5] Apr. 1, 1975 SHUTTER-FAN SYSTEM 2,479,668 8/1949 Brandon 123/4112 2,734,493 2/1956 Findley 123/41.l2 [76] lnvemor- Gordm Elmer 2378 Holly 2,957,459 10/1960 Tauschek... 123/4112 Lmfiuawafimanofianada 3,177,852 4/1965 Elmer 123/4112 KlV 7P1 3,265,047 8/1966 Elmer l23/4l.12

[22] Filed: May 1, 1973 Primary Examiner-Manuel A. Antonakas [21] Appl' 35614l Assistant ExaminerDaniel J. OConnor [52] U.S.Cl. 123/41.l2 l23/4l.05 51 1111. C1. F01p 7/02 [571 ABSTRACT of Search A ehicle coolant ystem incorporating a shutte ufan capable of restricting the passage of air through the [56] References Clted radiator section of the system until a predetermined UNITED STATES PATENTS coolant temperature at the engine inlet is achieved, the 2,169,121 8/1939 Coy 123/4112 Opening of the Shutter-fan to an air impelling Condi- 2,225,209 12/1940 Dewey.. 123/41 12 tion then being effected by a thermally actuated unit 2,284,938 6/1942 Allen 123/41.12 exposed to engine coolant at inlet conditions. 2,351,203 6/1944 Hanson 123/4112 2,437,810 3/1948 Earley et al 123/4l.12 5 Claims, 4 Drawing Figures 2,472,728 6/1949 Sanders 123/41.12

l J 116 l I 54 v 16223 112 7a \1 110 t 1 I 77 E c 94 I 76 7 4 124, 92 74 l 8 SHUTTER-FAN SYSTEM This invention is directed to a coolant system and in particular to a thermally operable shutter-fan to regulate the temperature of coolant fluid in relation to the system.

In the operation of vehicles under environmental conditions, of extreme cold, such as in the Arctic, problems arise concerning the suitable regulation of engine operating temperatures and in particular, the control of the temperature differential between outlet and inlet engine coolant.

The cylinder head temperature of internal combustion engines is generally regulated by the operation of a coolant-sensitive circulation-inhibiting thermostat located in the engine coolant outlet, by means of which the circulation of the coolant under thermo-siphon and water pump forces from the engine to the engine radiator is restricted or substantially prevented until a desired minimum coolant temperature at the engine outlet is achieved. The regulation of coolant flow including inflow from the radiator is usually controlled by restricting circulation at the engine coolant outlet. As is well known in the art, such operation may be readily effected using the well known type of wax-filled thermostate in the engine coolant outlet. However, one problem that arises is the question of temperature difference between the engine inlet and outlet temperatures of the coolant. If incoming coolant at an ambient temperature of 10F. in the radiator is admitted to an engine equipped with a l8()F. winter thermostat, then the coolant temperature differential across the engine is l7()F. A wide temperature differential of this order leads to a number of problems including reduced engine reliability, serviceability, and severely increased levels of harmful engine emmissions.

The problems encountered in operating an engine in such fashion under this type of climatic condition are aggravated by the extreme heat losses which take place directly from the engine block, due to large losses of heat by radiation and convection from the engine external surfaces, within the engine compartment. Such radiation and convection losses are directly affected by the flow of cold ambient air to the engine compartment due to wind, the motion of the vehicle, or the operation of the vehicle engine fan. Even the use of an electrically controlled fan of the prior art does not provide effective control of conditions within the engine compartment or tend to modify compartment conditions sufficiently.

The present invention provides a shutter-fan assembly for use with a temperature modifying system such as a vehicle engine cooling system, comprising; assembly mounting means for mounting the assembly in spaced relation with a radiator portion of the temperature modifying system; a rotor assembly attached in rotatable relation with the mounting means, having a substantially circular array of blades extending outwardly therefrom, at least some of the blades being moveable from a first flow obturating shutter condition to a second blowing position; thermally responsive means to move the moveable blades from one position to the other position, and means to rotate the rotor assembly whereby in operation when in the blade second position the assembly functions as a fan.

In the case of air cooled motors many of the benefits of the subject shutter-fan may be obtained by suitable installation.

The present invention further provides a method of operating a coolant circuit for an engine fluid coolant system having a fluid coolant suplied at a low temperature to the engine and ashutter-fan to regulate the passage of gaseous coolant in cooling relation with the system, including the steps of operating the engine to provide power therefrom; circulating coolant through the engine in cooling relation therewith; blending coolant from the radiator with coolant circulating in the engine; maintaining the shutter-fan in a substantially closed condition to impede the passage of coolant fluid in cooling relation through the radiator while permitting an increase in the temperature of coolant within the radiator and entering the engine from the radiator, sensing the thermalcondition of blended coolant entering the engine, and regulating the shutter-fan accordingly in an opening sense on attaining predetermined coolant inlet conditions to promote predetermined engine op erating conditions.

In the case of engines having liquid coolant circuits using the subject shutter-fan, the circulation of cooling air through the core of the radiator due to fan action is controlled, and the admission of cold air into the engine compartment is restricted.

In operating an engine by providing a regulated cooling thermal gradient in addition to benefits such as improved oil circulation, reduced thermal gradients and reduced thermal stresses, accelerated engine warm up and reduced crank case condensation, to name but a few, a further significant advantage is achieved in the case of vehicles having partially or completely enclosed engine compartments in that by controlling fan action the air temperature within the engine compartment is permitted to rise relatively rapidly to that associated with temperature conditions. The warmer engine compartment thus provides warmed combustion air, leading to enhanced performance in terms of fuel vaporization and improved fuel economy, with the achievement of exhaust temperatures even approaching design values and corresponding improvements in efficiency and reliability.

A major advantage of the shutter fan herein disclosed is the ease with which it may be installed in a vehicle without the need of expensive structural alterations or modifications to the vehicle, as may be entailed in alternative systems.

A further and not inconsiderable factor is the accelerated provision of a sufficient heat source for heating the interior of the associated vehicle, when required.

The present invention provides a shutter-fan having a controlling actuator responsive to the temperature of coolant within the vehicle engine. The use of a dynamically energized shutter within the protected confines of the engine compartment lends an assurance of dependable operation under conditions where other forms of shutter are liable to jam or malfunction. According to the invention a wax containing element having a change-of-state characteristic at a selected temperature may be used to power the shutter-fan from a bladeclosed to a blade-open position. Thus, if a wax containing unit having a wax which liquifies at approximately 170F. is connected in blade controlling relation with at least some of the blades of the shutter-fan, then on achievement of the selected temperature of l70F. the

coolant at the engine inlet, which temperature is transmitted to the wax element by appropriate local coolant circulation, the wax element expands, to cause operation of the device from the closed shutter" condition to an open Fan condition.

It is contemplated that instead of being direct acting, the temperature responsive element may operate in controlling relation with an independently powered servo system. However, it has been found that direct fan blade actuation may be achieved in the manner taught, to provide a simple and reliable system.

A further characteristic of the present invention is the use of a pre-loadedresilient linkage in the mechanism to facilitate the setting up and adjustment of the blade control linkages, which controls the opening and closure of the fan blades.

Certain embodiments of the present invention are de scribed reference being made to the accompanying drawings, wherein;

FIG. 1 is a schematic side view of an engine installation incorporating a shutter-fan according to the present invention;

FIG. 2 is a partial view of the shutter-fan assembly in elevation, as seen from the rear or engine side, and

FIG. 3 is a sectional side view of the shutter-fan assembly.

FIG. 4 is a top view of a blade boss 116 showing bushings 112 and cam spindles in off-centered relation.

Referring first to FIG. 1, the engine and cooling system assembly is shown beneath the hood ll of a vehicle. The coolant system 12 comprising a radiator 14 in combination with a subject shutter-fan 16. The radiator 14 is provided with air baffles 18,20 which form a coolant flow passage 22 within which is located the blades 24 of shutter-fan 16.

The radiator 14 is connected by bottom hose 25 and top hose 26 to the engine 28, the bottom hose 25 connecting the bottom tank 30 of the radiator with the inlet 32 of the coolant pump 34.

The radiator top hose 26 extends from the engine 28 to the radiator top tank 36, having a thermostat 38 located therein, in accordance with usual automotive practice.

A thermal bypass 40 connects the engine adjacent the coolant outlet with the pump inlet 32, to permit local circulation during warm-up.

While the pump 34 is shown separated from the block of the engine, being carried by extension 42 of the engine crankshaft it will be understood that this is primarily for illustrative purposes. Similarly, the circulation by-pass 40 in practice is often located within the engine block, while the thermostat 38 also is usually located internally within the engine, usually on top of the block.

The shutter-fan 16 is shown attached by mounting bracket 44 to the front of the engine, and has a pulley 46 in driven relation with engine pulley 48, driven by the engine crankshaft. A fan belt 50 connects the two pulleys.

An inlet connection 52 and outlet connection 54 connect the shutter-fan assembly with the engine coolant circuit, to provide engine coolant at engine inlet temperature from the pump 34 to the shutter-fan actuator assembly.

Turning to FIG. 2 the shutter-fan mounting bracket 44 is shown, having recess walls defining slots to receive mounting bolts 62. The blades 24 are shown in their fully closed position, forming a substantially closed shutter. In the closed shutter position blade balance weights 64 extend substantially normal to the plane of the blades 24. The balance weights 64 serve to off-set a shift in the blade center of gravity, on movement to an open position. Thus the balance weights provide a substantially constant center of gravity to each blade assembly.

Turning to FIG. 3, the mounting bracket 44 includes a boss 66 extending normally thereto, having progressively reduced portions 68, 70, 72 on which are mounted the bearings which support the rotor assembly.

Within the bracket 44 internal walls 74 together with cover plate 76 define a fluid sensing chamber 77 coaxial with the boss 66, having coolant passages 78 connecting with the respective coolant inlet and outlet connections 52,54.

A thermostat actuator 80 is located within the fluid sensing chamber 77, being secured at 81 by threaded attachment means. The actuator 80 or lower element has a presser spindle 82 extending forwardly therefrom (rightwardly as illustrated) in pressing relation with a resilient loading device' 84 comprising a plurality of Belleville washers arranged in pairs in back-to-back relation to form a compression spring. The resilient washer arrangement 84 in turn presses against a push rod 86 having a thrust bearing 88 mounted thereon by way of a threaded carrier 90 secured in adjustable relation to the push rod 86 by way of a lock nut 92 which in turn is secured by a locking tab 94.

A slide sleeve assembly comprises a sleeve portion 102 having an outer collar 104 and an inner collar 106.

The inner collar 106 is held in forward thrusting relation by the thermostatic actuator 80 acting on push rod 87 and the thrust bearing 88 working against a coil spring 108. The spring 108 is compressed between an end housing 110 of the rotor assembly and a series of bushings 112 mounted on respective cam spindles 114 which are attached in off-centered relation with the respective blade bosses 116. The blade bosses 116 are rotatably mounted on a cylindrical body portion 120 of the rotor assembly by suitable anti-friction thrust bearings to permit ready rotation of the blades about the radially extending polar axes of their respective bosses 1 16.

The rotor body portion 120 is rotatably mounted by,

In operation at low temperatures the shutter-fan blades are held in a closed condition by the coil spring 108 which acts in compression between the end housing 110 and bushings 112.

The bushings 112 are mounted on cam spindles 1 14. Each shutter blade 24 has a boss portion 116 about the main axis of which the blade 24 rotates. Each blade boss 116 has a spindle 114 extending axially therefrom and positioned eccentrically from the boss main or polar axis to provide a turning moment to the blade, under the action of spring 108 on the forward side and collar 104 acting against the rearward side of the spindle bushings 112.

Upon start-up of the engine 28 in a cold condition, the engine coolant circulates inwardly from the pump 34 into the engine block, and recirculates back to the pump inlet by way of the circulation by-pass 40. The

radiator 14.

When the coolant contacting the normal circulation thermostat 38 achieves a sufficient temperature to initiate opening of the thermostat 38, then some hot liquid coolant flows by way of top hose 26 into the radiator 14, and a corresponding mass of cold water from the bottom of radiator 14 is drawn by way of the bottom hose 25 through the pump 34 into the engine.

The coolant'recirculating in by-pass 40 mixes with radiator coolant flowing in from bottom hose 25. The temperature of coolant passing through pump 34 being modified accordingly.

lf ambient conditions permit, the flow of heated coolant through the radiator will become sufficient to raise the temperature of coolant leaving pump 34 and entering the engine to the desired predetermined operating temperature. The condition of engine ingoing coolant is conveyed to the sensing chamber 77 by connection 52 from the discharge of pump 34.

On reaching the predetermined temperature, the thermostat power element 80 within the sensing chamber 77 commences operation, the wax contents thereof expanding to produce forward motion of the pressure spindle 82. This motion is transferred by the belleville washers 84 into forward motion of the push rod 86.

The axially slidable push rod 86, together with the carrier 90 moves forward, carrying the thrust bearing 88 with it. The outer race portion of bearing 88 pushes against the inner collar 106 of the rotating sleeve assembly 100, to move the sleeve assembly 100 forward (to the right, as illustrated). This motion causes the sleeve outer collar 104 to be displaced forward axially, thereby moving the cam spindles 114 forwardly against the compressive force exerted by the spring 108.

Displacement of the cam spindles 114 axially causes rotation of the blade bosses 116, to move the blades 24 from a closed to an opening position.

Upon such movement the shutter-fan ceases to prevent a flow of air through the radiator 14, and the fan blades 24 cause air to flow through the radiator in accordance with the degree of blade opening.

It is not considered that the location of the wax element 80 in the assembly is critical and other locations are contemplated.

It will be understood that the subject arrangement is suitable for inward or outward aspirating fans.

In addition to controlling engine conditions during start-up, it will be understood that the shutter-fan system provides continuous protection during the operation of the engine. Thus, in the case of a vehicle hauling through mountainous terrain, on making descent down a hill, when windage cooling increases due to increased vehicle speed, and the rate of heat generation also markedly diminishes, the shutter-fan responds to the condition of the inlet coolant, and will thus tend to close-down somewhat, or even close right off to the shuttered condition.

While the illustrated embodiment shows blades in side by side relation, when closed, the blade edges can be made so as to overlap at this condition.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A shutter-fan assembly for use with a temperature modifying system, comprising: assembly mounting means for mounting the assembly in spaced relation with a temperature modifying system; a rotor assembly attached in rotatable relation with said mounting means, having a substantially circular array of blades extending outwardly therefrom, at least some of said blades being moveable from a first obturating position to a second, blowing position; thermally responsive means to move the moveable blades from one said position to the other said position, and means to rotate said rotor assembly whereby in operation when in said second blade position the assembly functions as a fan said blades being individually supported on anti-friction mountings for movement between said positions, each blade having a cam spindle off-set from the blade axis of movement, said thermally responsive means including a temperature sensitive pushing element in thermal contact with coolant inlet conditions to the engine, push rod means connected thereto for displacement axially within said rotor assembly, and anti friction thrust means connecting said push rod means with said blade spindles to accurately position said blades in response to changes in length of said pushing element produced by temperature change in said coolant, said push rod means including a resilient loading device to provide pre-determined pre-load to the push rod means.

2. The assembly as claimed in claim 1 in combination with a temperature modifying system having a radiator section, a coolant gas circulation path therethrough including a restricted path portion in facing cooperating relation with said rotor assembly, said rotor blades when in said first position serving to restrict passage of said coolant gas through said circulation path.

3. The combination according to claim 2 wherein said temperature modifying system comprises a vehicle coolant system.

4. The combination according to claim 3 wherein said vehicle coolant system comprises a propulsive engine of the vehicle connected in liquid coolant circulating relation with said radiator section, said shutter fan assembly being mounted rearwardly of said radiator section, said gas circulation restricted path portion comprising a portion of easing confining said gas circulation path, having an opening; therethrough in coincident axially aligned relation with said rotor assembly.

5. The assembly as claimed in claim 1 wherein said moveable blades each include a balance weight to maintain the center of gravity of a said blade at a constant radius from the axis of rotation of the shutter fan assembly, to minimize the force required to position said blade.

Claims (5)

1. A shutter-fan assembly for use with a temperature modifying system, comprising: assembly mounting means for mounting the assembly in spaced relation with a temperature modifying system; a rotor assembly attached in rotatable relation with said mounting means, having a substantially circular array of blades extending outwardly therefrom, at least some of said blades being moveable from a first obturating position to a second, blowing position; thermally responsive means to move the moveable blades from one said position to the other said position, and means to rotate said rotor assembly whereby in operation when in said second blade position the assembly functions as a fan said blades being individually supported on anti-friction mountings for movement between said positions, each blade having a cam spindle off-set from the blade axis of movement, said thermally responsive means including a temperature sensitive pushing element in thermal contact with coolant inlet conditions to the engine, push rod means connected thereto for displacement axially within said rotor assembly, and anti-friction thrust means connecting said push rod means with said blade spindles to accurately position said blades in response to changes in length of said pushing element produced by temperature change in said coolant, said push rod means including a resilient loading device to provide pre-determined pre-load to the push rod means.

2. The assembly as claimed in claim 1 in combination with a temperature modifying system having a radiator section, a coolant gas circulation path therethrough including a restricted path portion in facing cooperating relation with said rotor assembly, said rotor blades when in said first position serving to restrict passage of said coolant gas through said circulation path.

3. The combination according to claim 2 wherein said temperature modifying system comprises a vehicle coolant system.

4. The combination according to claim 3 wherein said vehicle coolant system comprises a propulsive engine of the vehicle connected in liquid coolant circulating relation with said radiator section, said shutter fan assembly being mounted rearwaRdly of said radiator section, said gas circulation restricted path portion comprising a portion of casing confining said gas circulation path, having an opening therethrough in coincident axially aligned relation with said rotor assembly.

5. The assembly as claimed in claim 1 wherein said moveable blades each include a balance weight to maintain the center of gravity of a said blade at a constant radius from the axis of rotation of the shutter fan assembly, to minimize the force required to position said blade.

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