GB2179133A - Radiator shutter control systems - Google Patents

Abstract

A shutter control system for controlling the flow of cooling air to a vehicle radiator, has a duct for directing the flow of air to the radiator and a shutter assembly 1 having shutter elements 2 movable to vary the flow of air through the duct. The shutter elements, which may be pivotally mounted louvres 2 connected together for simultaneously operation, are moved by actuating means 4 in accordance with the output from a temperature responsive means 3, such as an hydraulic piston and cylinder assembly or a metal coil, which senses the air temperature adjacent the radiator, and produces an output variable within a given range of sensed temperature. The actuating means 4 may comprise a mechanical device including for example cables rods and levers as appropriate. <IMAGE>

Description

SPECIFICATION Shutter control systems This invention relates to shutter control systems of the kind for controlling the flow of cooling medium to a prime mover or other source of heat.

It is well-known to provide such shutter control systems to control the air flow by which prime movers, such as liquid-cooled vehicle engines, are ultimately cooled. Such systems may include a thermostat, connected into the liquid cooling system of the engine, which operates to open and close a shutter assembly to control the air flow to the engine.

These systems have two main disadvantages arising from the use of the thermostat; firstly that it requires a connection into the liquid cooling system, and secondly that it provides only crude control of the shutter assembly, which has only two operating positions.

According to my invention, a shutter control system of the kind set forth comprises a duct for directing the flow of cooling medium to the prime mover, a shutter assembly having shutter elements movable to vary the flow of cooling medium through the duct, temperature responsive means for sensing the temperature of the cooling medium at a location adjacent to the prime mover, and producing an output which is variable within a given range of sensed temperature, and actuating means for moving the shutter elements to vary the flow of cooling medium in accordance with the output from the temperature responsive means.

My invention therefore provides variable control of the shutter assembly, so that the system is more efficient. Further, using a temperature responsive means which senses temperature adjacent to the prime mover has two effects; firstly, there is no interference with the prime mover, and secondly the temperature responsive means operates on waste heat.

The temperature responsive means is preferably adjustable, so that the range of temperatures for which the output is produced can be varied.

The temperature responsive means may comprise an hydraulic piston and cylinder assembly. Increase of temperature causes expansion of the fluid in the cylinder, so that the output is provided by the piston, which extends as the temperature increases. Alternatively the temperature responsive means may comprise a heat sensitive metal coil which extends axially as the temperature increases to cause movement of an output member.

The actuating means preferably comprises a mechanical device for transmitting the output movement from the temperature responsive means to operate the shutter elements. The particular arrangement of the actuating means, and the elements used, such as levers, cables or rods will depend on the relative positions of the temperature responsive means and the shutter assembly, and the space available.

Preferably, the actuating means includes a first plunger to which the output movement of the temperature responsive means is transmitted, a second actuating plunger operating the shutter elements, together with a lever to multiply the output movement, and flexible inextensible cable means for transmitting movement as required.

In one embodiment the first plunger operates a first lever which multiplies the output movement, and the cable transmits the movement from the first lever to the actuating plunger, which operates the shutter elements by means of a second, actuating lever.

In a modification a member movable with the first plunger transmits the output movement from the first plunger to the cable, which transmits it to the actuating plunger, and the actuating plunger operates an actuating lever which multiplies the output movement and controls the shutter elements.

In either embodiment the actuating means may include first biassing means acting on the first plunger to bias the temperature responsive means to its rest position, and second biassing means acting on the actuating plunger to bias the shutter elements to their rest positions. The shutter elements preferably comprise pivotally mounted louvres connected together for simultaneous operation.

The system may be arranged so that on failure of the temperature responsive means the shutter elements are closed to allow minimum flow through the duct. If this is not desirable, the system also includes means which in this event open the shutter elements to allow maximum flow through the duct. In either embodiment this may be achieved by providing a third biassing means exerting a force on the actuating lever which is opposite to, but less than, the force exerted by the second biassing means, with a releasable connection between the actuating plunger and the actuating lever, and a member operable in response to the temperature of the prime mover which operates following failure of the temperature responsive means to release the connection so that the third biassing means urges the actuating lever to open the shutter elements.

My shutter control system is simple and efficient, and is easy to install on any existing prime mover or heat source, particularly where the prime mover has a suitable duct already.

A kit comprising a suitable duct (where necessary), shutter assembly, temperature responsive means and actuating means may be made up for any given prime mover or heat source.

Some embodiments of a shutter control system in accordance with my invention are illustrated in the accompanying drawings, in which: Figure 1 is a plan view showing the general arrangement of a shutter control system; Figure 2 is an end view of the system of Figure 1; and Figure 3 shows a modification of the system.

The shutter control system shown in Figures 1 and 2 is adapted to control the flow of air to a radiator (not shown) for cooling an internal combustion engine (not shown).

The system generally comprises a duct (not shown) for directing the air flow to the radiator, a shutter assembly 1 having shutter elements in the form of louvres 2 movable to vary the flow of air through the duct, temperature responsive means 3 for sensing air temperature adjacent the radiator, and producing an output which is variable within a given range, and actuating means 4 for moving the louvres 2 in accordance with the output from the temperature-responsive means 3.

The louvres 2 are pivotally mounted in a rectangular frame, the lower member 5 only of which is shown in Figures 1 and 2, although the top member is similar. The lower member 5 is of F-section, and its parallel arms 6,7 have superimposed apertures 8,9 respectively. A pivot member for a louvre 2 is located in each pair of apertures 8,9. Each pivot member comprises a plastic clip 10 having a slot 11 in which the louvre 2 is received, and a portion 12 which passes through the apertures 8,9 and carries an operating lever 13, which is located between the arms 6,7. Each operating lever 13 is also pivotally mounted on a slide member 14, which is operated by the actuating means 4 and the temperature-responsive means 3 as follows.

The temperature-responsive means 3 comprises an hydraulic piston and cylinder assembly, which is mounted on a first bracket 15. The cylinder 16 has a nose portion 17 which is fixed to the bracket by a locknut 18.

The piston of the assembly acts through a piston rod 19, which is received in a blind bore 20 of a first plunger 21 guided for axial movement in the bracket 15. The plunger 21 is biassed towards the cylinder 16 by a first spring 22 acting between the bracket 15 and the circlip 23 on the plunger 21. When the temperature sensed by the assembly is within the given range, say 15"C to 25"C, the piston and rod 19 move in accordance with the temperature; extending as the temperature rises to provide the output. The minimum temperature of the range can be adjusted by adjusting the nose portion 17.

The output from the piston rod 19 acts through the plunger 21 on the actuating means 4. Thus the plunger 21 is pivotally connected to a link 24, which is in turn pivotally connected to one end of a first lever 25.

The lever 25 is pivoted on the bracket 15 at an intermediate point of its length, and the other end of the lever is connected to the inner member 26 of a flexible inextensible cable 27 by means of a pivot bolt 28, a clevis 29 and a nipple 30. The outer cable member 31 is mounted on an extension 32 of the bracket 15 by the locknut 33 and an adjuster 34. The cable 27 runs to a second bracket 35, which is pivotally mounted at 36 on a fixed member 37 to which the lower member 5 of the louvre frame is attached.

The outer member 31 is mounted on the bracket 35, while the inner member 26 is attached to one end of a second actuating plunger 38. The actuating plunger is guided for axial movement in the bracket 35, and at its other end is pivotally connected to an actuating lever 39 for the louvres 2. The actuating plunger 38 is biassed towards the lever 39 by a second spring 40, which acts between the bracket 35 and a circlip 41 on the plunger. A retainer 42 for the spring 40 is also mounted on the bracket. The actuating lever 39 acts on one louvre 2, and replaces the operating lever 13 for that louvre. The lever 39 is also connected to the slide member 14, so that movement of the lever 39 not only pivots the one louvre 2, but acts on the slide member 14 to ensure simultaneous movement of the other louvres.

In the position shown in Figure 1 the piston rod 19 is retracted by the first spring 22, and the louvres 2 are closed under the action of the second spring 40. The system remains in this position as long as the air temperature adjacent the engine radiator, as sensed by the piston and cylinder assembly, is below the given range. When this temperature is within the range, variation of the temperature causes the piston to extend or retract, operating the rod 19, plunger 21, lever 25, cable 27, actuating plunger 38 and lever 39 to open or close the louvres respectively. The lever 25 is arranged to multiply the output movement of the rod 19 to provide the correct amount of movement of the louvres 2. If the air temperature rises further, out of the given range, the piston rod 19 remains extended, and the louvres 2 remain open.

If the temperature responsive means 3 fails, the louvres 2 will be moved to the closed position shown in Figure 1. This is not suitable for an internal combustion engine, which will tend to overheat in such circumstances.

The system of Figures 1 and 2 therefore includes means for opening the louvres 2 to allow maximum air flow if the temperature responsive means 3 fails and the engine overheats. Thus, a third spring 43 is provided, which is anchored on a pin 44 fixed to the member 37 and a pin 45 on slide member 14 and acts in tension on the slide member 14 to bias the actuating lever 39 in a direction to open the louvres 2. The spring 43 does not affect normal operation, as the force it exerts on the lever 39 is less than the opposing force exerted by the second spring 40 acting on the lever 39 through the actuating plunger 38. The actuating lever 39 and the plunger 38 have a releasable connection; the lever 39 carries a pin 46 which engages in a recess 47 in the end of the plunger 38.The lever 39 and plunger 38 are normally held in engagement by a light tension spring 48 acting between the bracket 35 and the pin 45. (Springs 43 and 48 are not shown in Figure 2). The connection can be released by an L-shaped lever 49 pivoted to a second bracket 50 fixed to member 5. One arm 51 of the lever 49 acts on the plunger 38, while the other arm 52 is operated by a link 53 controlled by a solenoid 54 responsive to an overheat switch 55 which operates at a given engine temperature.

Normally the lever 49 is in the position shown in solid lines in Figure 1. If the engine overheats the switch 55 operates the solenoid 54, which pulls on the link 53, so that the lever 49 pivots into the position shown in chain-dotted lines. If the louvres 2 are closed when this happens, as they would be if the temperature responsive means 3 had failed, the lever 49 frees the actuating plunger 38 from the pin 46, and the spring 43 then acts on the actuating lever 39 to open the louvres 2. If the louvres 2 are not closed (or nearly closed) when the switch 55 operates, the lever 48 will not release the connection.

Figure 3 shows a simplified version of the system of Figures 1 and 2, and corresponding reference numerals have been applied to corresponding parts. In Figure 3 the lever 25 is omitted, and the circlip 23 on the plunger 21 is replaced by a member 56 to which the cable inner 26 is connected by a nipple 57.

The actuating plunger 38 slides in the spring guide 42, which is pivotally connected to the bracket 35. The plunger 38 is pivotally connected (by a clevis 58) to one end of an actuating lever 59, which has similar pivotal connections to a post 60 mounted on the bracket 35, and at its other end to a pivotal link 61. The link 61 is connected to the slide member 14 to operate the louvres 2. The lever 59 therefore performs the multiplying function of the lever 25 in Figure 1, as well as being the actuating lever. Although not shown in Figure 3, the link 61 has a releasable connection to the slide member 14, with means similar to those of Figure 1 for releasing the connection to open the louvres 2 if the engine overheats following failure of the temperature responsive means. The construction and operation of the embodiment of Figure 3 are otherwise the same as in Figure 1.

The embodiments shown are designed for use in vehicles, with the louvres 2 being located between a front grille and the radiator, and the actuating means arranged with the temperature responsive means 3 adjacent the radiator. Clearly the actuating means can be arranged in any suitable way, and may include other mechanical elements such as rods or rigid links, and rack and pinion elements. The actuating means used will depend on the particular prime mover or heat source used, and the space available. The system is simple to construct and install, and provides variable control of the louvres in accordance with the engine temperature, which ensures that the engine operates more efficiently.

Claims (14)

1. A shutter control system of the kind set forth comprising a duct for directing the flow of cooling medium to the prime mover, a shutter assembly having shutter elements movable to vary the flow of cooling medium through the duct, temperature responsive means for sensing the temperature of the cooling medium at a location adjacent to the prime mover, and producing an output which is variable within a given range of sensed temperature, and actuating means for moving the shutter elements to vary the flow of cooling medium in accordance with the output from the temperature responsive means.

2. A shutter control system as claimed in Claim 1, in which the temperature responsive means is adjustable, such that the range of temperatures for which the output is produced can be varied.

3. A shutter control system as claimed in Claim 1 or Claim 2, in which the temperature responsive means comprises an hydraulic piston and cylinder assembly.

4. A shutter control system as claimed in Claim 1 or Claim 2, in which the temperature responsive means comprises a heat sensitive metal coil.

5. A shutter control system as claimed in any preceding claim in which the actuating means comprises a mechanical device for transmitting the output movement from the temperature responsive means to the shutter elements.

6. A shutter control system as claimed in Claim 5, in which the actuating means includes a first plunger to which output movement of the temperature responsive means is transmitted, a second actuating plunger for operating the shutter elements, a lever for multiplying the output movement and flexible inextensible cable means for transmitting movement as required.

7. A shutter control system as claimed in Claim 6, in which the first plunger operates a first lever which multiplies the output movement, and the cable transmits the movement from the first lever to the actuating plunger, which operates the shutter elements by means of a second, actuating lever.

8. A shutter control system as claimed in Claim 6, in which a member movable with the first plunger transmits the output movement from the first plunger to the cable, which transmits it to the actuating plunger, and the actuating plunger operates an actuating lever which multiplies the output movement and controls the shutter elements.

9. A shutter control system as claimed in any of Claims 6 to 8, in which the actuating means includes first biassing means acting on the first plunger to bias the temperature responsive means to its rest position, and second biassing means acting on the actuating plunger to bias the shutter elements to their rest positions.

10. A shutter control system as claimed in any preceding claim, in which the shuttle elements comprise pivotally mounted louvres connected together for simultaneous operation.

11. A shutter control system as claimed in any preceding claim, including means to ensure that the shutter elements allow maximum flow of cooling medium on failure of the temperature responsive means.

12. A shutter control system as claimed in Claim 9 and Claim 11, in which the actuating means has a third biassing spring which exerts a force on the actuating lever opposite to, but less than the force exerted by the second biassing means, a releasable connection between the actuating lever and the actuating plunger, and a member operable in response to the temperature of the prime mover which operates following failure of the temperature responsive means to release the connection so that the third biassing means urges the actuating lever to open the shutter elements.

13. A shutter control system of the kind set forth, substantially as described herein with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.

14. A shutter control system of the kind set forth, substantially as described herein with reference to and as illustrated in Figure 3 of the accompanying drawings.