WO2014172778A1 - Coolant circulation pump having thermal control of sub- circuits - Google Patents

Abstract

The pump provides temperature-based flowrate-modulation of the main- flow of coolant through the engine and radiator, coupled with temperature-based open/close control of sub-flows of coolant through plural sub-circuits. Modulation is done by orientatable swirl- vanes. Open/close control is done by a movable sleeve rotating inside a stator-sleeve, which opens/closes apertures and windows in the sleeves.

Description

Title: COOLANT CIRCULATION PUMP, HAVING THERMAL CONTROL OF SUB-CIRCUITS

[0001] This technology relates to pumping apparatus for circulating liquid coolant around a coolant circulation system, for example the coolant system in an automotive engine. The apparatus includes a fixed housing, a rotary impeller having blades, and a rotary-driver for rotating the impeller. The circulation system includes a radiator or other main heat exchanger, and includes a plurality of subsidiary circulations or sub-circuits, which pump coolant around subsidiary heat exchangers .

[0002] The use is not ruled out of a special dedicated pump in one or more of the sub-circuits, but the preferred use of the technology involves the use of a single pump apparatus which has the capability to coordinate the coolant flowrate requirements of all the sub-circuits, over the whole operational temperature range to which the apparatus is subjected, thus obviating the need for additional pum s.

[0003] The technology is described mainly as it relates to a pump for a cooling system in an automotive engine.

[0004] The present technology is a development from the disclosures of patent publications US-6 , 309 , 193 ; US-6 , 499 , 963 ; US-6 , 887 , 046 ;

US-7 , 603 , 969. In this prior art, the coolant flowrate is modulated according to the temperature of the coolant. That is to say: as the temperature of the coolant rises, the flowrate at which the pump circulates the coolant through the radiator also rises.

LIST OF DRAWINGS

[0005] The technology will now be described with reference to the accompanying drawings, in which:

Fig 1 is a pictorial view of a pumping apparatus for pumping coolant around cooling circuits.

Fig.2 is another pictorial view of the apparatus, shown partly

sectioned.

Fig.2A is a sectioned exploded pictorial view of some of the internal components of the apparatus, showing especially a thermal actuator of the apparatus.

Fig.3 is a plan view of the apparatus of Fig.l, in which a top tier of the apparatus has been sectioned, showing sleeves of the apparatus .

Fig.4 is a circuit diagram showing the pump incorporated into the cooling circuits and sub-circuits.

Fig.5 is the same view as Fig.3, except that now the top tier has been removed and a middle tier of the apparatus has been sectioned, showing vanes of the apparatus.

Fig.6 is an elevation of the pump apparatus of Fig.l, sectioned on lines 6T-6T, 6M-6M, 6B-6B of Fig.3.

Fig.7 is a plan view of the pump, including a sectioned thermal- actuator of the apparatus.

Fig.8 includes four diagrams, designated 8-0, 8-2, 8-5, 8-8, which show the thermal actuator, arranged to control flowrate through both the sleeves and the vanes.

Fig.9 is a pictorial view of components of the thermal actuator. Fig.10 is an actuator diagram, which illustrates the interactions between the circuits and sub-circuits.

Fig.11 is a graph of the extension of the thermal-actuator (in

millimetres) as a function of coolant temperature.

Fig.12 is a graph showing the orientation of the swirl-vanes as a function of coolant temperature.

Fig.13 includes four diagrams designated 13-0, 13-1, 13-2, 13-3.

These diagrams differ in the positioning of a rotor sleeve of the apparatus, which has moved incrementally in response to changing temperature of the coolant.

Fig.14 appears with Fig.13, and includes two diagrams

designated 14-0,1,2, 14-3, which show different positions of the set of vanes of the apparatus.

Fig.15 includes four more diagrams, similar to those of Fig.13, designated 15-5, 15-6, 15-7, 15-8, which show further

positions of the rotor-sleeve.

Fig.16 appears with Fig.15, and includes four diagrams

designated 5-5, 5-6, 5-7, 5-8, which show further positions of the set of vanes.

Fig.17 is a sectioned plan view of another pump apparatus, having a pair of linear sleeves.

Fig.18 is a sectioned elevation of the pump of Fig.17.

Fig.19 is a sectioned plan view of a further pump apparatus, having two pairs of linear sleeves. Fig.20 is a sectioned elevation of the pump of Fig.19.

Fig.21 is a pictorial view of the sleeves of Fig.17, with associated thermal-actuator .

Fig.22 is a sectioned elevation of yet another pump apparatus,

having vanes pivotable about radial axes.

Fig.23 is a close-up of an area of Fig.22, highlighting the manner of sealing the sleeves.

Fig.24 is an actuation diagram (comparable to Fig.10) of a coolant circulation system for temperature control of battery coolant- flow.

[0006] The pumping apparatus 20 depicted in Figs.1-16 of the drawings is suitable to be incorporated into the coolant circulation system of an automotive engine. The apparatus 20 is basically in three tiers. The top tier 23 houses a pair of sleeves which control the flow of coolant to several sub-circuits of the system. The middle tier 25 houses a set-of swirl-vanes which control the main flow of coolant circulating between the engine and the radiator. The bottom tier 27 houses the impeller of the pump, and includes a volute chamber 90 for receiving the pumped coolant from the impeller and an outlet port for conveying same out to and around the system.

[0007] Fig.3 is a section of the top-tier 23, and depicts an outer fixed stator-sleeve 29 and an inner rotor-sleeve 30. The rotor-sleeve 30 is mounted for rotation in the housing 32, and is driven to rotate by a blocker-driver (described in detail below) of a thermal-unit. The thermal-unit includes a wax-element thermal- actuator 38. The thermal-actuator 38 includes a temperature-sensor, which is arranged to measure the temperature of coolant passing through the from-engine-conduit 40.

[0008] In the exemplary apparatus, the housing 32, in

conjunction with the sleeves 29,30, is arranged to create and define four sub-entry-chambers 41, being designated 41B; 41H; 41E; 41T (Fig.3). The sleeves 29,30 are formed with respective windows /apertures /slots 43, and bars 45 that lie between and define the same .

[0009] The rotor-sleeve 30 can be rotated relative to the stator-sleeve 29, in an open/close mode of movement, to a sleeves- open position, in which apertures 43RE in the rotor-sleeve 30 coincide or overlie windows 43SE in the stator-sleeve 29, whereby flow of coolant is enabled, through the flow-throats thus created. The sleeve 30 can be rotated also to a sleeves-closed position, in which apertures 43RE in the inner rotor-sleeve 30 coincide with bars 45SE in the outer stator-sleeve 29, whereby flow of coolant through the sleeves is blocked.

[0010] Taking the sub-entry-chamber 41E as an example, when the sleeves 29,30 are in their open-position, in respect of the sub- entry-chambers 41E, coolant flows through the sleeves from that sub- entry-chamber and enters the subs-impeller-chamber 47. The subs- impeller-chamber 47 is funnel-shaped, and coaxial with the axis of the impeller, and funnels the coolant into the centre (eye) of the impeller 49 of the pump.

[0011] Fig.6 is a circuit diagram of the overall cooling system of a typical vehicle. Cooled coolant from the pump 20 enters the engine E via a pump-outlet conduit, being the impeller-engine conduit 50. During normal warmed-up running, the from-engine conduit 40 and the to-radiator conduit 52 convey hot coolant from the engine E to the radiator R. The from-engine conduit 40 routes the hot coolant through a temperature-sensing chamber 54 of the pump apparatus, where the hot coolant bathes the wax-element temperature- sensor inside the body 56 of the thermal-actuator 38.

[0012] A bypass-branch conduit 58 divides out from the from- engine conduit 40 to the bypass-sub-entry-chamber 41-B. If the sleeves 29,30 are in the open-position with respect to the

chamber 41-B, bypass flow takes place, whereby coolant recirculates through the engine E without passing through the radiator R. If the sleeves 29,30 are in the closed-position in respect of the

chamber 41-B, bypass flow does not take place, i.e all the flow goes through the radiator. Having passed through the radiator, the now- cooled coolant enters the pump via a radiator-pump conduit 60.

[0013] The circuit that includes the impeller 49, the impeller- engine conduit 50, the engine E, the from-engine conduit 40, the temperature-sensing chamber 54, the to-radiator conduit 52, the radiator R, and the radiator-pump conduit 60, is referred to as the main radiator-circuit. [0014] Coolant circulating around the radiator-circuit passes through the middle tier 25 of the pump 20, where the flowrate is modulated in accordance with its as-measured temperature, by the set of swirl-vanes 61. Coolant circulating around the main radiator- circuit does not pass through the top-tier 23 and does not pass through the sleeves 29,30.

[0015] When coolant emerging from the engine is not yet warmed up, i.e is cold /cool, the designers arrange for flow through the radiator to be blocked, and for the coolant to bypass the radiator and to be routed back into the engine without being cooled, via the bypass-subs-impeller-chamber 41-B — the sleeves 29,30 being now open with respect to that chamber. The designers will usually arrange for the bypass and the radiator to be both open at the same time, during the warm-up process, e.g when the warm-up process is nearing completion.

[0016] The circuit that includes the impeller 49, the impeller- engine conduit 50, the engine, the from-engine conduit 40, the temperature-sensing chamber 54, the bypass-branch conduit 58, the bypass-sub-entry-chamber 41-B, the sleeves 29,30, and the subs- impeller-chamber 47, is referred to as the bypass-sub-circuit, and is one of the four sub-circuits of the overall system.

[0017] The sub-circuits pass through the top-tier 23 of the pump 20, and the flow of coolant in these circuits is controlled by whether the sleeves 29,30 are in their open or closed position of the sleeves 29,30 with respect to the particular sub-circuit, which in turn is controlled by the temperature of the coolant. Coolant circulating around the sub-circuits does not pass through the middle-tier 25 of the pump, but passes through the top-tier 23, and through the sleeves 29,30.

[0018] Fig.3 is a sectioned plan view of the middle tier 25 of the pump 20. Here, the swirl-vanes 61 are pitched around a circle that is concentric with the axis of the impeller 49. There are fifteen vanes 61 in the example (three of which are omitted (for clarity) from Fig.3). Coolant enters the impeller 49 by passing radially inwards through the spaces 63 between the vanes 61. (The impeller 49, though visible in the view of Fig.3, in fact lies in the bottom tier 27 of the pump.)

[0019] The vanes 61 are provided with respective pivot-pins 65, which engage respective pivot-holes 67 in the housing 32. Thus, the vanes 61 cannot move bodily with respect to the housing 32, but they can rotate with respect to the housing.

[0020] The vanes 61 also carry respective drive-pins 69. A vanes-actuation ring 70 is mounted for rotation in the housing 32, and the ring 70 is provided with respective drive-slots 72. The vanes drive-pins 69 engage the drive-slots 72 in the ring 70. Thus, when the vanes-actuation ring 70 rotates, the vanes do not move bodily in the housing, but the vanes do all rotate, in unison, about their pivot-pins 65, in a vanes-orientation mode of movement. As can be seen from the drawings, the vanes change their orientation with respect to each other, in unison, in response to a rotation of the vanes-actuation ring 70.

[0021] The pump apparatus 20 is so arranged that the vanes- actuation-ring 70 is driven to rotate in response to changes in coolant temperature. If the temperature of the coolant remains constant, the orientation of the vanes 61 does not change. Thus, the orientation of the vanes 61 is determined by the temperature of the coolant.

[0022] At one end of the range of orientation of the vanes 61, when the coolant is cold, the vanes are closed and sealed together, such that coolant is blocked from passing through from the

modulator-entry-chamber 74 to the main-impeller-chamber 76. As the coolant warms up a little, from cold to cool, the vanes 61 crack open, permitting coolant to flow through the spaces 63. At first, the spaces 63 between the vanes 61 is small, and flow is relatively low by the fact of the smallness.

[0023] As the temperature of the coolant increases above warm, the geometry of the vanes 61 is such that further orientation of the vanes basically does not significantly change the sizes of the spaces 63 between the vanes. That is to say: even though the vanes 61 continue to change their orientation as the coolant goes from warm to hot, and beyond, the geometry of the shape of the vanes is such that the cross-sectional area — i.e the flow-transmitting throat-area — of the spaces 63 remains, now, more or less constant. (In fact, the throat area of the spaces 63 increases from the vanes- closed position through the 'with' (flow-reduce) swirl range until the neutral vane position, then decreasing slightly through the 'against' (flow-boost) range of orientation.)

[0024] Again: when the coolant temperature goes from cold to tepid/warm, the flow of coolant increases because the spaces 63 between the vanes become larger, and because the effect of the 'with' (flow-reduce) swirl is becoming less. But once the coolant is warm, and hotter, the sizes of the spaces 63 has now reached a maximum.

[0025] The vanes 61 impart a rotational swirl onto the flow of coolant emerging from the vanes, entering the main-impeller- chamber 76, and entering the blades of the impeller 49. If the angular velocity of the imposed swirl is of the same sense as that of the impeller, the flowrate is reduced. If the angular velocity of the imposed swirl is of the opposite sense to that of the impeller, the flowrate is increased or boosted. It may be noted that, below warm temperatures, the velocity vector of the flow leaving the vanes imparts a rotational swirl onto the coolant, as the coolant enters the blades of the impeller, that is in the same sense as the rotational sense of the impeller, i.e the induced swirl is 'with' the impeller.

[0026] The vanes 61, when undergoing the change in orientation occasioned by the coolant going from warm to very-hot, procure a change in the sense of the angular velocity of the swirl from 'with' to 'against' the rotation of the impeller. Thus the flowrate of the coolant passing through the impeller is reduced when the coolant is warm, and is boosted when the coolant is very hot. (The terms 'flow-reduce' and 'flow-boost' are to be compared only with each other: the flowrate passing through the vanes increases steadily and progressively as the coolant progresses from cool to tepid to warm to hot to very-hot. During fully warmed-up operation, the coolant temperature can be expected normally to fluctuate between warm and very-hot, and the terms 'flow-reduce' and 'flow-boost' can be related to a neutral condition, the terms then being more meaningful.

Discussion of these terms also appears elsewhere in this specification. )

[0027] A thermal-unit of the apparatus includes the thermal- actuator 38. The thermal-actuator 38 includes the body 56,

containing expandable wax. As the temperature of the coolant flowing over the body 56 increases, the wax expands, and drives a movable stem 78 further out of the body 56. Thus, the thermal- actuator 38 senses the temperature of the coolant, and the extension of the movable stem 78 can be regarded as a measure of the changing temperature .

[0028] The movable stem 78 engages a movable slider 80, which is guided in the housing for sliding movement. The slider 80 is equipped with two drive-pegs, one of which is a sleeves-drive- peg 81S and protrudes upwards, and the other is a vanes-drive- peg 81V and protrudes downwards. The upward sleeves-drive-peg 81S engages a sleeves-drive-slot 83S in a lug 85 of the inner rotor- sleeve 30. The downward vanes-drive-peg 81V engages a vanes-drive- slot 83V in the vanes-actuation-ring 70.

[0029] As the coolant temperature increases, the stem 78 moves out of the body 56 of the thermal-actuator 38, carrying the

slider 80 with it. The sleeves-drive-peg 81S engages the sleeves- drive-slot 83S in the lug 85 of the inner rotor-sleeve 30, thereby causing the rotor-sleeve to rotate. The vanes-drive-peg 81V engages the vanes-drive-slot 83V in the vanes-actuation-ring 70, thereby causing the orientations of the vanes 61 to change, all in unison.

[0030] The apparatus includes a blocker-driver , which receives the thermal movement of the stem 78 of the thermal-actuator 38 and converts that movement into rotational movement of the rotor- sleeve 30. The blocker-driver includes the slider 80, the sleeves- drive-peg 81S, the lug 85, and sleeves-drive-slot 83S of rotor- sleeve 30.

[0031] The apparatus includes also a vanes-driver, which receives the thermal movement of the stem 78 of the thermal- actuator 38 and converts that movement into orientational movement of the vanes 61. The vanes-driver includes the slider 80, the vanes-drive-peg 81V, the vanes-drive-slot 83V in the vanes- actuation-ring 70, and the respective vanes-drive-pegs 81V of the several vanes 61.

[0032] The engagement of the sleeves-drive-peg 81S with the sleeves-drive-slot 83S, and the engagement of the vanes-drive- peg 81V with the vanes-drive-slot 83V, include respective lost- motion relationships, which will now be described with reference to Fig.8. Fig.8 is a diagram for illustrating operational

interactions, and does not represent the physical shapes of the components. Fig.9 illustrates how the lost-motion relationships are procured, in the example.

[0033] In Fig.8-0, the coolant is cold, the stem 78 having not extended at all from the body 56 of the thermal-actuator 38. The sleeves-drive-peg 8 IS rests against the bottom of the sleeves-drive- slot 83S. The vanes-drive-peg 81V rests against the bottom of the vanes-drive-slot. (Here, the terms top, bottom, etc, accord with the orientation of Fig.8, not to the operational positions of the components . )

[0034] Upward movement of the stem 78 from the Fig.8-0 position will result in the sleeves-drive-peg 81S pushing the rotor-sleeve 30 into rotation (lug-spring 87 being strong enough not to compress when supporting the force needed to drive the rotor-sleeve 30 to rotate), and will result in the vanes-drive-peg 81V moving freely upwards along the vanes-drive-slot 83V, without moving the vanes- actuation-ring 70. Thus, this cold-to-cool initial movement of the stem 78 is lost motion, as far as the vanes-actuation-ring 70 is concerned.

[0035] In Fig.8-2, the coolant is cool, and the stem 78 has advanced two mm. The vanes-drive-peg 81V has reached the top end of the vanes-drive-slot 83V, and so any further movement of the stem 78 now will drive the vanes actuation-ring 70 to rotate. Further movement of the stem 78 will also cause the rotor-sleeve 30 to undergo further rotation.

[0036] In Fig.8-5, the coolant is warm, and the stem 78 has extended to five mm. The vanes-drive-peg 81V is driving the vanes- actuation-ring 70 into further rotation. However, the lug 85 of the rotor-sleeve 30 has now reached the top end of the lug-recess 89 in the stator-sleeve 29, thereby blocking any further movement of the rotor-sleeve 30. Now, further movement of the stem 78 will merely cause the lug-spring 87 to compress, but will not move the rotor- sleeve 30. Thus, this warm-to-very-hot final movement of the stem 78 is lost motion, as far as the rotor-sleeve 30 is concerned.

[0037] In Fig.8-8, the coolant is very-hot. The rotor-sleeve 30 remains in the same position as in Fig.8-5. The vanes-actuation- ring 70 has now rotated to its full extent, driving the vanes, now, to their maximum flow-boost orientation, whereby the flowrate of the coolant is at a maximum.

[0038] In the depicted example, there are (notionally) five sub- entry-chambers 41, namely: the bypass sub-entry-chamber 41B; a heater sub-entry-chamber 41H; a turbocharger sub-entry-chamber ; a transmission-oil-cooler TOC-sub-entry-chamber 41T; and an engine- oil-cooler EOC-sub-entry-chamber 41E. (These particular sub- circuits are simply examples, for illustration. The present technology is applicable to temperature-based open/close control of sub-circuits generally, of many kinds.)

[0039] If it happens that two of the sub-circuits are alike as to the temperatures at which the designers require them to

open/close, those two sub-circuits can be combined in the pump housing, i.e both can be routed through one single sub-entry- chamber. In the present case, the designers elected to keep both the heater and the turbocharger sub-circuits open to the impeller all the time, and therefore the turbocharger cooler sub-circuit can share the heater-sub-entry-chamber 41H with the heater sub-circuit. Thus, in this case, only four (i.e not five) separate mutually- isolated sub-entry-chambers 41 are provided around the sleeves 29,30 in the top tier 23 of the housing 32.

[0040] The sub-entry-chambers 41 are arranged around the circle of the sleeves 29,30. The coolant flows inwards from the several sub-entry-chambers 41, through the apertures 43 in the sleeves 29,30 (if these are open), and into the subs-impeller-chamber 47.

[0041] In the depicted example, there are fifteen apertures 43R in the inner rotor-sleeve 30, and also fifteen bars 45R that separate and define the apertures 43R. In the depicted example, there are fifteen windows 43S in the outer stator-sleeve 29, and also fifteen bars 45S that separate and define the windows 43S.

(Usually, these numbers will be equal, but equality is not

essential . )

[0042] The flows of coolant from the separate sub-circuits are routed through the separate sub-entry-chambers 41. In respect of the sub-circuit-E , for example, the coolant from the sub-circuit-E enters the sub-entry-chamber 41E, and passes through the (three) apertures 43RE that are available to that sub-circuit, and into the subs-impeller-chamber 47.

[0043] Regarding the sub-entry-chamber 41E, each of the three windows 43SE in the stator-sleeve 29 corresponds to a specific one of the apertures 43RE in the rotor-sleeve 30, and to a particular one of the bars 45RE in the rotor-sleeve. For example, the

window 43SE in the outer stator-sleeve 30 can overlie either (a) the bar 45RE in the inner rotor-sleeve 30, or (b) the aperture 43RE, depending on the temperature of the coolant. If the window 43SE overlies the aperture 43RE, the sub-circuit-E is open, and flow can pass through to the subs-impeller-chamber 47. But if the

window 43SE overlies the bar 45RE (which is the condition actually illustrated in Fig.3) the sub-circuit-E is closed, and flow cannot now pass from the sub-entry-chamber 41E through to the subs- impeller-chamber 47.

[0044] It is the task of the designers to see to it that, when the rotor-sleeve 30 rotates, the rotor-sleeve is movable between the open-condition in which the window 43SE in the stator-sleeve 29 overlies the aperture 43RE in the rotor-sleeve 30, and the closed- position in which the window 43SE in the stator-sleeve 29 overlies the bar 45RE in the rotor-sleeve 30.

[0045] It is noted that the sleeves 29,30 can, at one and the same time, be in (a) an open-position with respect to one sub-entry- chamber 41, and (b) a closed-position with respect to another of the sub-entry-chambers .

[0046] The designers determine the volumetric flowrates of the coolant flows that are required to be circulating in the several sub-circuits. When the apertures in the sleeves are fully open, in respect of a particular one of the sub-circuits, the designers see to it that the aggregate throat area of the sleeves and windows 43 available to that sub-circuit is adequate to enable the desired flowrate. Thus the aggregate throat area of the three windows 43SE and the three apertures 43RE that lie in the sub-entry-chamber 4 IE should be large enough to enable the flowrate the designers desire to be circulating in the sub-circuit-E . The different sub-circuits have (or might have) different flowrate requirements, and the differences can be reflected in the number and size of the

apertures .

[0047] The designers bear in mind the fact that the rotational position of the rotor-sleeve 29 is determined by coolant

temperature. The designers pay careful attention to the positions of the leading and trailing edges of each of the apertures in the rotor-sleeve, and to the interaction of those edges with the leading and trailing edges of each aperture in the stator-sleeve .

[0048] If it should be the case that a first one of the sub- circuits requires only half the flowrate of another of the sub- circuits, the designers should see to it that the aggregate flow- through throat area of the sleeves apertures available to the first sub-circuit is adequate for that first flowrate, and that double that area is available for the other sub-circuit. For each sub- entry-chamber, the designers have to set the sizes of the apertures such that, when the apertures are open, the aggregate flow- transmitting area is large enough to accommodate the maximum flow required for the particular sub-circuit associated with that chamber .

[0049] It may be noted that the shape or configuration of the top tier 23, in which the sleeves components are housed, though of a compact axial height, lends itself to the basically-cylindrical sleeves 29,30 being of large diameter. Thus, the configuration of the top tier is such as to present designers with an ample length of circumference in which to accommodate not only the required throat areas of apertures needed to convey the desired flowrates, but to accommodate also the bars for closing those apertures, and to accommodate also the movement of the rotor to open and close all the various sub-circuits at the desired temperatures.

[0050] On the other hand, although the shape of the top tier provides room, in the depicted example, for the rotary sleeves to be of ample diameter, it should also be noted that the sleeves can alternatively be arranged advantageously for linear movement, rather than rotational movement, as will be described below.

[0051] In the present case, the designers have stipulated that the sub-circuit-T and sub-circuit-E should start off closed (when the coolant is cold) and should then start to open (not immediately, but soon) after the coolant temperature has moved towards cool, and should be completely open by the time the coolant is warm. The designers desire the sub-circuit-T and the heater sub-circuit-E to stay open all the time. The bypass sub-circuit-B is desired to open when the coolant is cold, and to stay open through cool and tepid, and then to close again as the coolant moves through tepid towards warm.

[0052] These operations are illustrated graphically in Fig.10.

In setting the operational parameters, designers should bear in mind the functional link between the closed/open condition and the reduce/boost condition, at particular temperatures, when setting the temperatures at which the sub-circuits are opened/closed. This is true especially of the bypass sub-circuit, in that designers should ensure that the swirl-vanes have started to open, enabling radiator- cooling of the coolant to take place, well before the bypass sub- circuit closes, which happens when the coolant is in the tepid to warm range.

[0053] It is emphasized that the designers' requirements as to different modes of temperature-dependent open/close operations of the main-circuit and of the several sub-circuits can (nearly) all be accommodated — whatever the designers are likely to favour. It is just as simple to arrange a sub-circuit to be closed-then-open-then- closed as it is to arrange it to be closed-then-open. It is a simple exercise to procure the openings and closings at the desired temperatures. It should be noted that the open/close actions do not commence and finish suddenly, but these operations go from start to finish over a range of temperatures — but this is advantageous rather than otherwise.

[0054] The full lines that appear in Fig.10 should be understood to represent the coolant-passing throat-areas that vary in size as the apertures 43R in the rotor-sleeve 39 move with respect to the windows 43S in the stator-sleeve 30. This change in the throat-area through the sleeves is created by the changing extension of the stem 78 of the thermal-actuator 38, in dependence upon the

temperature of the coolant. These full lines in Fig.10 are straight lines, i.e the relationship between thermal-actuator extension and change in throat-area is substantially linear.

[0055] The aperture /windows when fully open are sized to have equivalent cross-section to the incoming coolant sub-circuit conduits — this offering negligible incremental resistance to the sub-circuit, thus diminishing dissipative power consumption during warmed-up operation. The multiplicity of apertures are used to accommodate a short actuator stroke as is characteristic of the wax- element units as show herein, but fewer but wider apertures may be employed in conjunction with actuators having greater linear or rotary movement capability.

[0056] Like any other fluid passage, restrictive feature or valve, the apertures contribute resistance or energy dissipation due to shear of the fluid when passing through it, and is known to be represented by a second order relationship between the fluid flow velocity and the pressure drop created by such resistance.

[0057] While fluid power required for centrifugal coolant pumps is proportional to the cube of the change in fluid flow velocity and that a restrictive aperture effectively increases the fluid flow velocity and friction for a given flow rate; this has little detrimental effect at lower flow rates. So, because the aperture opening is smaller during warm-up, when the coolant flow rate is relatively low, the energy dissipation effect is negligible, and more benefit ism derived from causing the lubrication fluids (engine and transmission oil) to warm up more quickly.

[0058] As the variable flow and pressure output afforded by the adjustable pre-swirl vanes responding to the warming up coolant is increasing in concert with the opening of the apertures in the supplementary flow circuits, the fluid power consumption is

relatively low during the warm-up phase and appropriately more when cooling demand is high, but the power consumption is not

detrimentally affected by the apertures, as they are designed to be sufficiently sized so as not to introduce unnecessary resistance to coolant flow.

[0059] In contrast, traditional conventional coolant pumps that have been designed to overcome the significant resistance offered by conventional thermostats consume relatively more power at all operating modes, since they produce greater coolant flow and pressure to overcome the dissipative effects of such restrictive valves .

[0060] The exemplary apparatus affords both optimal warm-up which renders fuel savings and lower emissions, and the variable flow affords less parasitic power draw which renders fuel savings. Together the aggregate reduction in fuel consumption (fuel savings) plus reduced emissions (of C02 , CO, NOX, and unburned hydrocarbons) is greater than heretofore achieved by the variable flow and flow control valves employed separately.

[0061] The moveable guide vanes have for many years been known to be the most efficient method to vary output of various turbo- machinery and centrifugal pumps, certainly more efficient than restrictive valves that by their very definition dissipate the energy in the fluid by causing disturbance in the flow. Also, quick warm-up of the lubrication fluids in engines and drive trains results in less energy consumed to overcome friction.

[0062] Together the aggregate fuel savings derived from these tow effects in the exemplary apparatus is greater than that achieved prior independently. It is however equally noteworthy that the resulting reduction in "emissions" due to proper combustion which occurs when the engine is warm (not cold) is very significant. So, the flow control valve plus the "gradually" increasing and efficient variable flow output during the warm-up phase renders in aggregate greater emissions reduction than these methods derive independently.

[0063] In the depicted example, the rotor-sleeve 30 basically does not move after the coolant is warmed up. However, the present technology gives designers the flexibility to also provide

temperature control of flowrate in a sub-circuit, using the sleeves, during normal warmed-up operation, if that should be desired. [0064] Fig.11 is a graph showing the relationship between temperature (°C) and stem extension (mm) for a typical thermal- actuator 38. The relationship between an incremental increase in temperature and the corresponding incremental extension of the stem 78 is typically not linear for a wax-motor powered actuator but can be designed to be linear if other actuation devices are

employed.

[0065] Indicated in Fig.11 is the relationship between

temperature and thermal-actuator extension when the temperature is rising. It should be noted that, when the temperature is falling, the indicated extensions occur at temperatures that may be five or ten degrees lower than those indicated.

[0066] Fig.12 is a graph showing the changes in radiator flowrate corresponding to changes in coolant temperature, as determined by the orientations of the swirl-vanes 61 — as

determined by the extension of the thermal-actuator stem — as determined by coolant temperature. The vanes remain sealed closed, blocking flow to the radiator, while the coolant goes from cold to cool. The vanes start to open, allowing a trickle of flow through the radiator, as the coolant goes from cool to tepid. The coolant being cool to tepid, the coolant flow through the radiator is throttled by the smallness of the spaces 63 between the vanes. The designers have provided that, the coolant being cool to tepid, some of the coolant goes straight back to the engine without being cooled, in that the bypass is open at this time.

[0067] As the coolant temperature moves from cool through tepid to warm, so the throat-area of the spaces 63 increases. When the coolant is hot, the size of the throat-area has now more or less reached its maximum. As the coolant moves beyond hot, the spaces between the vanes starts to becomes smaller. Yet still the flowrate increases, because the changing orientation of the vanes changes the swirl from positive (or 'with') swirl to negative (or 'against') swirl, as the flow enters the impeller. Thus, it is emphasized that, although the throat area of the spaces between the vanes decreases slightly as the coolant moves from hot to very-hot, still the flowrate increases — because of the increasing negative

('against') swirl. [0068] The difference is emphasized between the manner in which flowrate through the vanes is controlled over the different

temperature ranges. When the coolant temperature is rising within the range cold to warm, the radiator flow increases due to the combined effect of the opening and decreasing positive swirl of the vanes plus the related closing of the bypass flow passage. But when the coolant is rising within the range warm to very-hot, the flowrate through the vanes is now modulated by the changing velocity vector of coolant as it emerges from the vanes.

[0069] When the coolant is warming, the vanes are so oriented that the flow enters the impeller in the same rotational sense as the spin of the impeller; when the coolant is very-hot, the flow enters the impeller in the opposite rotational sense to the

impeller. The senses being opposite (negative swirl), flowrate is boosted; the senses being the same (positive swirl), flowrate is comparatively reduced.

[0070] Fig.10 is a diagram showing the designers' choices as to how the temperature-controlled operations of the various sub- circuits are to be integrated together, and into the main circuit, in the particular example. It will be understood that other designers might choose other ways of integrating the circuits.

Also, the number of sub-circuits can be changed, and the sub- circuits might relate to temperature-controlled operations that are not described herein. The point is that the present technology gives designers flexibility of choice as to how to integrate the temperature-controlled sub-circuits that are present in a particular coolant-circulation system — or even to add such sub-circuits, knowing they can easily be controlled.

[0071] The pump apparatus 20 as described provides the

flexibility to accommodate many modes of circuit integration in a compact and inexpensive package. When it comes to the compactness of the apparatus, the following points may be noted.

[0072] The shape and size of the bottom tier 27 of the

apparatus 20 is dictated by the presence of the impeller 49 and its rotary driver, and by the need to accommodate the volute 90, in which the pumped coolant is collected. In the example, the bottom tier 27 is basically puck-shaped (i.e the axial height of the tier is significantly smaller than its diameter — like an ice-hockey puck) . Whatever shape the designers provide in respect of the bottom tier, still the shape has to accommodate, in some manner, an impeller and a volute, and the basic puck-shape would generally be a good choice.

[0073] The shape and size of the middle tier 25 of the apparatus is dictated by the presence of the set of vanes 61, arranged in a circle that is concentric with the axis of the impeller 49, and by the need to accommodate the (preferably heart-shaped) modulator- entry-chamber 74. Thus, in the example, the middle tier 25 also is basically puck-shaped — and of similar basic shape and size to the bottom tier 27. The bottom tier 27 and the middle tier 25 are compatible with each other, in terms of their ability both to be accommodated in the same overall compact housing unit.

[0074] The shape and size of the top tier 23 of the apparatus is dictated by the presence of the pair of sleeves 29,30, arranged in a circle that is concentric with the axis of the impeller 49, and by the need to accommodate the several sub-entry-chambers 41. It is recognized that, in the example, the top tier 23 also lends itself to being puck-shaped — and of similar basic shape and size to the bottom tier 27 and the middle tier 25. Thus, it is noted that the bottom tier 27 and the middle tier 25, and now also the top tier, are compatible with each other, in terms of their capability to be, all three, accommodated in the same overall compact housing unit.

[0075] It should be noted that, even when the top tier is configured to accommodate a pair of sleeves in which the relative movement is linear (rather than rotational) movement, still the shape and size of the top tier is (or can be) compatible with the other tiers. Examples of linearly-movable sleeves are discussed below.

[0076] It goes without saying that the space in and around an automotive engine for accommodating pumps and the like is at a huge premium. The present technology enables the components to be packaged compactly, neatly, and economically.

[0077] The contrast may be made with a pump design in which, for example, an axially-short wide tier might be combined with e.g an axially-long cylindrically-slim tier. Even if such a shape were to have a smaller overall volume, still such a shape would pose large problems as to where and how it can be accommodated on the engine and under the hood of the vehicle.

[0078] The internal nature of all three tiers 23,25,27 is basically that of a rotating structure having an axial length that is considerably shorter than its diameter, and that structure is surrounded, in each tier, by a chamber. In each tier 23,25,27, that chamber also can be of short axial length. Thus, in the present technology, it is recognized that the components that are to be present in the pump apparatus can be accommodated in a very compact package, each tier complementing the others.

[0079] It is not essential that the pump apparatus should be in three physically-separable tiers. However, making the tiers separable is convenient in the present case. Each tier can be designed such that the (sometimes intricate) components can be assembled into the housing of the tier, and the tier can basically be finished, and tested and inspected, at least in some respects, as a separate module, prior to being bolted to the other tiers.

[0080] Naturally, designers of coolant circulation systems spend time seeking to make the shape and size of the components as easily- accommodatable as possible into the available high-premium space. Thus, the compactness of the package that can be achieved, using the present technology, is to be welcomed.

[0081] Figs.13, 14 are diagrams of the changing positions of the rotor-sleeve 30 as the stem 78 of the thermal-actuator extends, millimetre by millimetre, as the coolant temperature increases. Figs.14, 15 (which appear with Figs.13, 15 are diagram of the changing positions of the swirl-vanes 61 as the stem 78 of the thermal- actuator extends, millimetre by millimetre, as the coolant

temperature increases .

[0082] In Fig.13-0, the coolant is cold, whereby the stem of the thermal-actuator has not (yet) started to extend, and the rotor- sleeve 30 is at the clockwise extremity of its rotational travel. In this cold position, the bars 45 in the sleeves 29,30 are blocking the passage of coolant, from the several sub-entry-chambers 41 of some of the sub-circuits, through to the sleeve-impeller chamber 47 — including the bypass 41B. Also, the vanes 61 are closed

sealingly together, whereby flow is blocked from the modulator- entry-chamber 74 through to the sleeve-impeller chamber 47.

However, in this case, the sleeves are designed to allow the turbocharger and heater sub-circuits to remain open.

The vanes are sealingly closed, as shown in Fig.14-0 , 1 , 2 , blocking flow to the main-impeller-chamber 76 and to the radiator.

[0083] In Fig.13-1, the coolant temperature has risen above

'cold', and the stem 78 has extended one millimetre, causing the rotor-sleeve 30 to start its rotational mode of movement. The apertures 43R in the rotor-sleeve and the windows 43S in the stator- sleeve are so arranged that the first thing to happen is that the apertures and sleeves in the bypass-sub-entry-chamber 41B start to open, allowing coolant to enter the subs-impeller-chamber, and thence to the impeller and to circulate around the engine. The turbocharger and heater sub-circuits remain fully open. The sub- circuits-E and -T remain blocked.

The vanes remain sealingly closed, as shown in Fig.14-0 , 1 , 2 , blocking flow to the main-impeller-chamber 76 and to the radiator. The coolant is not subjected to cooling at this time.

[0084] In Fig.13-2, the coolant temperature has gone from cold to cool, and the stem 78 has extended one millimetre.

The rotor-sleeve has moved such that the bypass sub-circuit 41B is now fully open. The turbocharger and heater sub-circuits remain open. The sub-circuits-E, -T are just starting to open.

The vanes remain sealingly closed, as shown in the

position 14-0,1,2, blocking flow to the main-impeller-chamber 76 and to the radiator. The coolant is not subjected to cooling at this time .

[0085] In Figs .13-3 , 14-3 , the coolant temperature is rising towards 'tepid', and the stem 78 has extended three millimetres.

Now, the bypass sub-circuit is starting to close. The turbocharger and heater sub-circuits are partly-open.

The vanes 61 have now started to open. A small flow of coolant can pass through the spaces 63 between the vanes, into the main- impeller-chamber 76, and into the radiator, whereby the coolant is now being subjected to some cooling.

[0086] In Figs .15-5 , 16-5 the coolant temperature has risen to

'warm', and the stem 78 has extended five millimetres.

Now, the continuing movement of the rotor-sleeve has blocked off the bypass sub-circuit. The turbocharger and heater sub-circuits remain open. The sub-circuits-E, -T are opening.

The vanes 61 have opened further (i.e the throat-area defined by the spaces 63 has increased) . An increased flow of coolant can now pass into the main-impeller-chamber 76, and through the radiator.

[0087] In Figs .15-6 , 16-6 the coolant temperature is rising towards 'hot', and the stem 78 has extended six millimetres.

Now, the bypass sub-circuit remains blocked. The turbocharger and heater sub-circuits remain open. The continuing movement of the rotor-sleeve has fully opened the sub-circuits-E, -T, and the movement of the rotor-sleeve has now reached its limit (i.e further increase in coolant temperature produce no further movement of the rotor-sleeve) .

The vanes have opened further, and the throat area defined by the spaces 63 has now reached its maximum. The vanes are oriented such that the rotary swirl imparted to the coolant flow by the vanes, is 'with' the rotation of the impeller, whereby the flow is in the 'reduced' condition.

[0088] In Figs .15-7 , 16-7 the coolant temperature is 'hot', and the stem 78 has extended seven millimetres.

The sub-circuits remain in their respective six mm conditions.

The vanes are oriented such that the rotary swirl imparted to the coolant flow by the vanes, is now neutral, i.e neither 'with' nor 'against" the rotation of the impeller, whereby the flow through the impeller is no longer 'flow-reduced'.

[0089] In Figs .15-8 , 16-8 the coolant temperature is 'very-hot', and the stem 78 has extended eight millimetres.

The sub-circuits remain in their respective six mm conditions.

The flow of coolant through the radiator-circuit has increased, because the movement of the stem has oriented the vanes such that the rotary swirl imparted to the coolant flow by the vanes, is now in the flow-boost condition, i.e the induced rotary swirl is now 'against' the rotation of the impeller. [0090] It can be regarded that extensions beyond eight mm represent not-usually-encountered high temperatures.

The sub-circuits remain in their respective six mm conditions.

The flow of coolant through the radiator-circuit continues to increase as the temperature continues to rise, because the vanes are being oriented further into the flow-boost condition — i.e the rotary swirl vector of the flow is increasing in the 'against' direction .

[0091] It will be understood that the new technology permits/ enables designers to open/close the sub-circuits in accordance with the temperature of the coolant, and in accordance with the desired cooling parameters of the particular installation. The as-described interactions between the as-described sub-circuits, and their coordination with the modulation of the main coolant flow by orientation of the vanes, as described herein, are not intended to limit the technology, but rather to illustrate what is possible, given the level of control that the technology enables.

[0092] As described, the subs-impeller-chamber conveys the subs- impeller-flow of coolant into the impeller. The main-impeller- chamber conveys a main-impeller-flow of coolant into the impeller. A separator 92 separates the two chambers, and separates the subs- impeller-flow from the main-impeller-flow, until the two flows are both on the point of entering the impeller.

The main-impeller flow (being the flow that circulates through the radiator) is: (a) conveyed to the impeller via the main-impeller chamber, and (b) the subject of temperature-based swirl-control of flowrate, as described. The subs-impeller-flow (being the

aggregation of sub-flow-T in sub-circuit- , sub-flow-H in sub- circuit-H, etc) is: (a) conveyed to the impeller via the subs- impeller-chamber, and (c) the subject of temperature-based on/off control of the sub-circuits, opening/closing at different

temperatures from each other.

[0093] The sub-flow-A circulating in sub-circuit-A enters sub- entry-chamber-A. The sub-entry-chamber-A is separated from the subs-impeller chamber by the sub-flow-blocker-A. The sub-flow-A can pass through from the sub-entry-chamber-A to the subs-impeller chamber if the sub-flow-blocker-A is open. If the sub-flow- blocker-A is closed, the sub-flow-A is blocked. [0094] The impeller-subs-flow is the aggregate of sub-flows from the different sub-circuits, which are passing through the subs- impeller-chamber, and then entering the impeller. Any sub-flow that is not blocked, at the particular temperature, is part of the subs- impeller-flow in the subs-impeller chamber.

[0095] The subs-impeller chamber is so configured as to ensure that the subs-impeller-flow, immediately prior to entering the blades of the impeller, has a substantial axial-velocity vector- component, and has a substantially-zero radial-velocity vector- component. That is to say, the subs-impeller chamber is so

configured as to ensure that there is no vector-component of velocity in the subs-impeller-flow that would tend to make the overall translational-velocity (as opposed to rotational- or angular-velocity) of the subs-impeller-flow anything but coaxial with the impeller.

[0096] It is not ruled out that the subs-impeller-flow might have a rotary swirl velocity, with or against the rotation of the impeller, i.e the subs-impeller-flow, in the subs-impeller-chamber , can have an angular-velocity vector-component that is coaxial with the impeller. But the subs-impeller-chamber preferably is so shaped that the translational-velocity, i.e the linear-velocity vector, of the impeller-sub-flow is coaxial with the axis of the impeller.

[0097] In Figs.1-16, the sleeves have been cylindrical, and arranged in a rotor-inside-the-stator format, and the two sleeves have been structured for relative rotation. Alternatively, as shown in Figs.17, 18, the inner and outer sleeves are again cylindrical, but now the inner movable-sleeve 130 moves linearly, rather than rotationally, with respect to the outer stator-sleeve 129. The outer stator sleeve can be formed monolithically into the pump housing 132.

[0098] In Figs.17, 18, it is less convenient to arrange the respective sub-entry-chambers 141 of the plural sub-circuits sectorially around the circumference of the cylindrical sleeves as in Figs.1-16. Now, the sub-entry-chambers 141 are disposed

sequentially along the axial length of the sleeves.

[0099] The movable-sleeve 130 is formed basically as a series of moulded-plastic cups, each cup 131 comprising a base and a cylinder. The open end of the cylinder sealingly clips over a suitable form on the base of the adjacent cup. When joined, the cups move in unison when acted upon by the thermal-actuator 138. (The end-cup 131end is not fixedly joined to the other cups, and the end-cup in fact moves away from the joined-together other cups over certain temperature ranges . )

[0100] The cups 131, when joined, create a series of separate internal hollow compartments. Openings in the sleeves communicate these compartments inside the moveable sleeve 130 with the sub- entry-chamber 141. The ports connecting the compartment with the sub-entry-chamber of the particular sub-circuit remain open during operation, so that the interior compartment of the cup 131 is effectively a part of the sub-entry-chamber 141.

[0101] The cylindrical wall of the cup is formed with

apertures 143A, that face windows 143W formed in the cylindrical wall of the outer-sleeve 129. (In this case, the outer-sleeve is integrated into the housing — as it can be in the other pumps described herein.) The windows 143W communicate with the subs- impeller-chamber 147 of the particular sub-circuit. When coolant is flowing in that sub-circuit, the apertures 143A coincide with the windows 143W, whereby the coolant passes from the sub-entry- chamber 141 (of which the interior compartment of the cup is a part), through the apertures 143A, through the windows 143W, debouching into the subs-impeller-chamber 147 and thence into the impeller .

[0102] The designers have arranged that, when the coolant is within a temperature range at which the designers desire to allow coolant to circulate around the particular sub-circuit (and thus the thermal-actuator stem is at the extension corresponding to that temperature) the movable sleeve 130 has moved so that the windows and apertures coincide, allowing flow to pass through. When the designers desire coolant flow to be blocked in respect of that particular sub-circuit, over a particular temperature range, they arrange for the thermal-actuator to move the movable-sleeve 130 to such position that the apertures in the movable-sleeve coincide with bars 145 in the outer-sleeve (in the housing). [0103] One of the sub-circuits, in this case the bypass sub- circuit, feeds coolant into the centre of the end cup 131end.

Again, windows in the outer sleeve 129 interact with apertures in the inner movable-sleeve (i.e with the interior of the end cup), in accordance with temperature of the coolant, to open the bypass-sub- entry-chamber 141B with the subs-impeller-chamber 147.

[0104] The blocker-driver 181 receives movement from the stem 178 of the thermal-actuator and converts that movement into linear movement of the movable-sleeve 130 lengthwise with respect to the housing, opening and closing the apertures and windows in the sleeves in response to changing temperatures of the coolant, in a similar manner to that described with respect to the rotational sleeves .

[0105] The subs-impeller-chamber 147 conveys coolant from those of the sub-circuits that are open at a particular temperature, into the impeller 149. All the sub-circuits debouch into the subs- impeller-chamber 147.

[0106] It will be understood that the linearly-movable sleeves of Figs.17, 18 are highly equivalent, functionally, to the

rotationally-movable sleeves of Figs.1-16. Also, the above- described lost-motion capability of the blocker-driver that connects the stem of the thermal-actuator to the movable-sleeve also can be readily provided when the movable-sleeve moves linearly rather than rotationally .

[0107] Fig.19 shows the blocker-driver 181, which involves guide-ways 182 on the cups 131, which interact with the sleeves- drive-peg 181S in much the same manner as the sleeves-drive-slot 83V interacted with the sleeves-drive-peg 8 IS. The wax-element thermal- actuator 138 also drives the modulator, which again is a set of orientatable swirl-vanes, via the vanes-drive-peg 181V.

[0108] It may be noted that the linear sleeves 129,130 can be accommodated in/on the top tier hardly less conveniently than the rotary sleeves. It is also noted that both the rotary sleeves and the linear sleeves can and do both feed their flows of coolant from the plural sub-entry-chambers 41,141 into a subs-impeller- chamber 47,147 that is located in the centre of the top tier, on the axis of the impeller.

[0109] In Figs, 20, 21, a sub-entry-chamber 241X has been added, which is separate from the other sub-entry-chambers 241T,E. An extra wax-element thermal-actuator 239 has been provided for operating the movable-sleeves 230X — which is in addition to the thermal-actuator 238 that had been provided in respect of the other sub-entry-chambers .

[0110] The thermal-actuator 238 measures the temperature of the coolant flowing from the engine to the radiator, as in the previous drawings; the temperature measured by the extra thermal-actuator 239 can be the temperature of a different flow, which is routed through the extra temperature-sensing-chamber 254X.

[0111] There is a practical limit to the number of cups 231 that can be strung together; placing another assembly alongside enables more sub-circuits to be added. It may be noted that the extra pair of sleeves, the extra thermal-actuator, the extra temp-sensing chamber, can all be accommodated in the top tier.

[0112] Fig.22 illustrates another alternative pump. In the previous drawings, the swirl-vanes 61 were arranged to pivot about axes that lie parallel to the axis of the impeller. At the moment the modulator-impeller-flow left the vanes, the flow had the following velocity vector-components, namely: a radially-inwards translational-velocity vector-component, and a rotational (angular- velocity) vector-component. In passing through the main-impeller- chamber 76, the flow was turned through 90°, whereby the radial translational-velocity vector-component was transformed into an axial translational-velocity vector-component, i.e with a velocity parallel to the axis of the impeller. (This refers to the

predominating translational-velocity vectors of the flow — of course the flow contains eddies and turbulences.) Thus, the annular modulator-impeller-flow entered the blades of the impeller with a helical velocity, i.e with a combination of axial translational and angular velocities imposed by the vanes.

[0113] In Fig.22, the required helically-swirling nature of the modulator-impeller-flow is already present as the coolant emerges from the vanes 361. However, while the vanes 361 in Fig.22 are more favourably oriented from the standpoint of imparting a swirl velocity onto the flow, the vanes themselves, and the mountings therefor, and the structures for driving the vanes to change orientation in unison with each other, can be mechanically complex. For example, the simple peg-and-slot connection 69,72 between the vanes 61 and the vanes-actuation-ring 70 in Figs.7, 8, 9, has been superseded in Fig.22 by gear teeth 392 on the spindle of each vane, which mesh with a gear-toothed actuation-ring 370. The vanes- actuation-ring 370 is driven to rotate, as before, by the stem of a wax-element thermal-actuator 338V.

[0114] In Fig.22, the inner and outer sleeves 329,330, which control flow between the sub-entry-chambers 341 and the subs- impeller-chamber 347, are in the linear format (as in

Figs .17 , 18 , 19 ) . The sleeves 329,330 are actuated by a separate sleeves-thermal-actuator 338S. The heater sub-circuit is open all the time, and flow from the heater-sub-entry-chamber 341H passes straight though into the subs-impeller-chamber 347.

[0115] When the vanes are arranged to be orientatable about radial axes, as in Fig.22, it can be difficult to close the vanes together to form a seal to prevent flow through to the radiator when the coolant is cold. Such seal is, however, desired, and in Fig.22 the radiator flow through the vanes 361 is blocked, when the coolant is cold, not by the vanes 361 themselves, but by a supplementary pair of sleeves 329X,330X.

[0116] The mechanical arrangement of the supplementary

sleeves 329X,330X is similar to that of the sleeves 29,30 (though performing a different role -- the supplementary sleeves 329X,330X provide open/close control of the main-flow between the radiator- pump conduit 360 and the modulator-entry-chamber 374, whereas the sleeves 29,30 provided open/close control of coolant flow in the sub-circuits, between the sub-entry-chambers 41 and the subs- impeller-chamber 47).

[0117] Again, in Fig.22, the subs-impeller-flow emerging from the linear sleeves 329,330 is contained within the subs-impeller- chamber, while the modulator-impeller-flow emerging from the radially-pivoting swirl-vanes 361 is contained within the modulator- impeller-chamber 374. Again, the separator 394 keeps the axially- flo ing, non-rotating, subs-impeller-flow separate from the axially- flowing, helically-rotating, annular modulator-impeller-flow, until both flows are on the point of entering the blades of the impeller.

[0118] Again, the supplementary sleeves 329X,330X are

mechanically similar to the sleeves 29,30, and the manner of sealing the sleeves is similar, and will now be described with reference to Fig.23. The sleeves are formed as plastic-mouldings, and the interface between the inner and outer sleeves is on a slight taper, within the general right-cylindricity of the sleeves. Leakage at the interface is prevented by the presence of a (moulded) sheet of soft sealing material 396, located between the tapered surfaces. Ribs 398 moulded onto the inside surface of the seal-sheet 396 engage complementary grooves moulded into the outer surface of the inner-sleeve 330X, so that the seal-sheet moves with the inner- sleeve .

[0119] Alternatively, the seal 396 may be formed as a coating on one of the sleeves 329X,330X. O-rings 399 are also provided to aid in sealing. The inner sleeve is urged upwards, compressing the seal, by means of a wave-spring 397, the spring force being reacted against the housing.

[0120] The present technology has utility — not just in automotive engines — but generally when there is a need for sophisticated control of liquid flowrates in plural circuits, related to changing temperatures in the coolant, in which some or all of the circuits include respective heat exchangers. Usually, the coolant liquid is water (with or without antifreeze) but it could be some other liquid. Some of the heat exchangers, at least some of the time, feed heat into the overall system, and some take heat out of the system; some take heat out at some temperatures and put heat in at other temperatures. The expression 'coolant' should be construed broadly, to include liquids to which heat is added, and liquids from which heat is extracted.

[0121] Some automotive engines employ low-temperature cooling circuits, so-called because they operate at temperatures lower than typical engine cooling systems. An example is charge-air cooling for turbocharged engines. This cooling system can be integrated into the pump apparatus as described.

[0122] Another example is battery cooling for hybrid and electric vehicles, a circuit diagram of which is shown in Fig.N. The batteries should be heated if below e.g 20°C, and cooled if above e.g 35°C. The present technology also can be employed in such a case.

[0123] In Fig.24, the battery pack 420 is provided with a heater 423 in series with the batteries, and a chiller sub- circuit 425 in parallel. When starting from cold, the coolant is cold enough to cause the sleeves 429,430 to be in position to open the bypass, and the vanes to be in position to block flow to the radiator. (If the coolant is cold enough, the battery heater 423 is activated.) As the coolant from the battery-pack 420 warms, the vanes 461 open to allow flow to the radiator, and to close the bypass .

[0124] As the coolant circulating through the battery pack attains normal running temperatures, the coolant flow is modulated by orienting the swirl-vanes, in accordance with coolant

temperature, in the manner previously described, thus maintaining desired battery cooling circuit temperature.

[0125] If the coolant from the battery-pack were to rise too high in temperature, chiller-flow in the chiller-sub-circuit 425 is enabled by movement of the sleeves, which opens that sub-circuit. The chiller-sub-circuit is arranged to transfer heat from the battery coolant to the refrigerant in the vehicle air-conditioner ( not shown ) .

[0126] In the examples, the manner in which the temperature of the coolant is sensed is that the bulb of a wax-element thermal- actuator is in the path of coolant emerging from the engine and heading for the radiator (or for the bypass circuit if the coolant is not yet warmed up). Other ways of sensing temperature, besides the wax-element unit, are contemplated. Also, other ways of converting the sensed temperature into movement of the actuator.

[0127] The automotive pump apparatuses depicted in Figs.1-18 have a combined thermal-unit. The thermal-unit is 'combined' in the sense that the modulator-driver and the blocker-driver are both controlled by the one thermal-actuator. The wax-element unit 38 includes the temperature-sensor and the movable-element of the thermal-actuator .

[0128] Designers may prefer to include two or more temperature- sensors, e.g located at different points in the system, and to include e.g a computer for coordinating the signals from those several sensors, for more sophisticated control of the sleeves and vanes. In that case, the expression "temperature-sensor" as used herein should be so construed as to encompass the two or more temperature-sensors together.

[0129] The temperature-sensor can be e.g an electronic sensor, or several such sensors, arranged to sense temperature of the metal of the engine. In this case, the sensors are still measuring the temperature of the coolant, though indirectly.

[0130] Similarly, designers may prefer to provide two or more physically separate movable-elements of the thermal-unit. For example, an apparatus might include e.g a blocker-movable-element and a modulator-movable-element, as shown in Figs.19-22. In that case, the expression "movable-element" of the thermal-unit should be so construed as to include those two or more movable elements together .

[0131] In the drawings, the movable-element is shown as the stem of the wax-element thermal-actuator. In an alternative, the moveable-element is an electric drive to supply the power to drive the blocker. The drive is switched on/off in unison with changing temperatures .

[0132] As shown, the impeller is mounted and driven from below the bottom tier, which leaves the upwards-facing side of the impeller free and open for receiving the modulator-impeller-flow and the subs-impeller-flow. As explained, the modulator-impeller-flow forms a helically-rotating annulus around the axially-moving column of the subs-impeller-flow. However, it might be the case that the drive to the impeller comes into the apparatus from above the top tier; in that case a shaft (and possibly bearings, seals, etc) are located in the top and middle tiers of the apparatus, and in that case the subs-impeller-flow passes around these centrally-located structures. Thus, in that case, the subs-impeller-flow itself is an annulus, and the helically rotating modulator-impeller-flow would form a wider annulus surrounding the subs-impeller-flow annulus.

[0133] The vanes 61 are pitched in a circle that is concentric with the axis of the impeller 49. The main-impeller-chamber 76 receives the coolant flow emerging from the vanes, and directs the flow into and through the blades of the impeller. Depending on the orientation of the vanes, the vanes impose a spiral/ helical velocity vector upon the modulator-impeller-flow of coolant emerging from the circle of vanes.

[0134] In the apparatus depicted in Figs.1-16, as the modulator- impeller-flow leaves the vanes and enters the main-impeller- chamber 76, the linear (i.e not including the angular) component of velocity of the modulator-impeller-flow can be regarded as only- radial. That is to say: the modulator-impeller-flow, immediately upon emerging from the vanes, has a more-or-less-zero axial linear- velocity vector-component. The main-impeller-chamber 76 turns the modulator-impeller-flow through 90°. Thus, when the modulator- impeller-flow enters the blades of the impeller, it can be regarded that the translational-velocity vector of the modulator-impeller- flow is predominantly-axial, i.e without significant net vector- components of translational velocity in other directions.

[0135] Here, the term 'spiral-flow' is 'flow having a substantial angular-velocity vector-component, but substantially zero axial linear-velocity vector-component'. 'Helical'-flow is flow 'having a substantial axial linear-velocity vector-component, in addition to its substantial angular-velocity vector-component'. That is to say: spiral-flow simply swirls: helical-flow swirls and moves axially.

[0136] Thus, in the apparatus of Figs.1-16, the modulator- impeller-flow, at the moment it leaves the vanes, is 'spiral'. But at the moment the modulator-impeller-flow enters the blades of the impeller, the modulator-impeller-flow — having now acquired a substantial axial linear-velocity — is 'helical'.

[0137] In the alternative depicted in Fig.22, the swirl-vanes can be so arranged that the modulator-impeller-flow, upon leaving the vanes with the described imposed angular-velocity, leaves the vanes at an angle that itself includes an axial component. In fact, the vanes can be arranged so that the modulator-impeller-flow leaves the vanes — with the imposed angular-velocity, and — with a purely-axial (i.e zero radial) translational-velocity. (This arrangement of the vanes is not new, having been disclosed, for example, in Fig.3 of US-6 , 309 , 193. ) Now, at the moment it leaves the vanes, the modulator-impeller-flow has a translational-velocity that is more or less only-axial, and thus can be regarded right away as helical flow. )

[0138] The swirl-vanes impose a spin-velocity (i.e an angular- velocity vector-component) on the modulator-impeller-flow of coolant passing into the impeller. The orientation of the vanes determines the magnitude and direction of the imposed spin-velocity. The directional sense of spin-velocity can be either (a) 'with', or (b) 'against' the spin of the impeller. (If the impeller is spinning clockwise, a clockwise spin-velocity is 'with' the impeller. )

[0139] (It is generally regarded that, when the spin of the flow is 'with' the impeller, the angle at which the flow enters the impeller is termed 'positive': and when the spin of the flow is 'against' the impeller, the angle is termed 'negative'. It is emphasized that a negative pre-swirl angle procures increased flow, while a positive pre-swirl angle procures comparatively reduced flow. )

[0140] An imposed 'with' spin-velocity will reduce the magnitude of the flowrate (i.e the litres/minute) of the modulator-impeller- flow passing into the blades of the impeller. An imposed 'against' spin-velocity will increase, or boost, the magnitude of the

flowrate. (The 'reduce' and 'boost' orientations of the vanes are measured against a 'neutral' orientation, being that orientation of the vanes at which the coolant leaves the vanes with no swirl velocity at all.)

[0141] The orientation of the swirl-vanes is determined by the temperature of the coolant. Thus, the flowrate of the modulator- impeller-flow is determined by the temperature of the coolant.

[0142] During normal warmed-up operation of the cooling system, the flowrate of the modulator-impeller-flow, as determined by the varying orientation of the vanes, has a minimum flowrate when the coolant is at the warm end of its normal working range during everyday operations, and a maximum flowrate when the coolant is at the very-hot end of the normal working range.

[0143] The following numbers are intended to be illustrative

(but the fact of mentioning the numbers should not be construed as a limitation). The term 'warm', here, is the temperature of the fully-warmed-up coolant at the low-end of the normal range of temperatures. (It is possible for the coolant to go below this warm temperature during normal running, but that is infrequent.)

Typically, the 'warm' temperature would be e.g 90°C. (The

temperatures, here, are of coolant in the from-engine conduit 40, as measured in the temperature-sensing chamber 54.) Similarly, the term 'very hot' describes the temperature of the fully-warmed-up coolant at the high-end of the normal range of temperatures. Again, it is possible for the coolant to go above this 'very-hot'

temperature during normal running, but the times that happens are infrequent enough to be considered as being outside the range at which it is worthwhile striving for maximum pumping efficiency. In a typical case, the 'very-hot' temperature would be e.g 110°C.

[0144] The term 'hot' describes the temperature of fully-warmed- up coolant in the middle of its normal-working range, being the temperature at which the designers are aiming to procure the most efficient pumping. In the typical case, the 'hot' temperature is e.g 100°C.

[0145] It should be noted that some cooling systems (or some components) operate normally at considerably lower temperatures. In those cases, typical warm, hot, and very-hot, temperatures would be e.g 70°C, 80°C, 90°C, and other systems are lower. The

functionality of the present technology does not depend on the temperatures being those typically encountered in cooling systems of car-sized automotive engines.

[0146] The designers should aim, generally, to provide a coolant flowrate level that procures properly effective cooling, over the range of coolant temperatures, and should aim to enable the pumping to be done, at that level, with a minimum of expenditure of pumping energy. Insofar as maximizing pump efficiency during normal running at a particular condition involves sacrificing efficiency under other conditions, designers should aim to secure peak pumping efficiency at the 'hot' temperature, in that that temperature represents the most prevalent duty condition, from which the maximum energy savings may be derived.

[0147] The required coolant flowrates at the 'warm' and 'very- hot' temperatures, in a typical case, might be e.g 100 litres/min and 200 litres/min. Again, these figures are merely typical, and in large commercial engines the flowrates might be e.g five times greater. Typically, the maximum normal flowrate (at the 'very-hot' temperature) would be of the order of double the minimum normal flowrate (at the 'warm' temperature), but this should not be

construed as a specific limitation.

[0148] It has been referred to, herein, that apart from the main-impeller-flow with its angular-velocity component, no

significant flow of coolant should enter the impeller with a significant velocity component, whether translational or rotational, other than an axial-velocity component that is coaxial with the axis of the impeller. This should be understood to distinguish from structures in which e.g a jet of coolant is deliberately injected into the stream of coolant, from the side, in a manner that causes the stream to deviate significantly from its axial flow vector. Of course, coolant passing through the conduits and chambers of a pump apparatus is subject to eddies and turbulences - but these do not take away from the notion the translational-velocxty vector of the flow of coolant as it enters the impeller should be predominantly- axial, and should be coaxial with the axis of the impeller.

[0149] In its preferred form, the pump of the present technology includes, and operates as, a series of temperature-controlled on/off valves, which open and close over a predetermined range of

temperatures. The preferred pump should not be seen as a

distribution-valve, which operates to switch flow directly from one circuit to another. However, in an alternative, the designers can arrange, for example, that a sub-entry-chamber receives flow from one sub-circuit at a low temperature, but then switches over to receive flow from another sub-circuit at a higher temperature, including simultaneously. Designers can arrange for the sleeves to be positioned to transmit either flow, or both flows together, or to block both flows, at different temperatures, or as desired.

[0150] Some of the physical features of the apparatuses depicted herein have been depicted in just one apparatus. That is to say, not all options have been depicted of all the variants. Skilled designers should understand the intent that depicted features can be included or substituted optionally in others of the depicted apparatuses, where that is possible.

[0151] Some of the components and features in the drawings and some of the drawings have been given numerals or names with letter suffixes, which indicate left, right, etc versions of the

components. The numeral or name without the suffix has been used herein to indicate the components or drawings generically.

[0152] Terms of orientation (e.g "up/down", "left/right", and the like) when used herein are intended to be construed as follows. The terms being applied to a device, that device is distinguished by the terms of orientation only if there is not one single orientation into which the device, or an image (including a mirror image) of the device, could be placed, in which the terms could be applied consistently.

[0153] Terms used herein, such as "cylindrical", "coaxial",

"vertical", and the like, which define respective theoretical constructs, are intended to be construed according to the purposive construction .

[0154] The terms axial, radial, centre, circumference, and the like, used herein, refer to the rotational axis of the impeller if not otherwise stated.

[0155] The scope of the patent protection sought herein is defined by the accompanying claims. The apparatuses and procedures shown in the accompanying drawings and described herein are

examples .

[0156] The numerals appearing on the drawings are listed as:

20 pumping apparatus top tier

middle tier

bottom tier

outer stator-sleeve

inner rotor-sleeve

pump housing

wax-element thermal actuator unit

from-engine conduit

sub-entry chambers

B bypass-sub-entry chamber

E sub-entry chamber

H heater-sub-entry chamber

T sub-entry chamber

windows /apertures /ports /slots

R apertures in the rotor-sleeve

S windows in the stator-sleeve

bars

subs-impeller chamber

impeller

impeller-engine conduit

to-radiator conduit

temperature-sensing chamber

fixed body of the wax-element unit 38

temperature-sensing bulb of the wax-element unit bypass-branch conduit

radiator-pump conduit

swirl-vanes

spaces between swirl-vanes

vanes pivot-pins

pivot-holes

vanes drive-pins

vanes-actuation ring

drive-slots in ring 70

modulator-entry chamber

subs-impeller chamber

movable stem of the wax-element unit 38

movable slider

S sleeves-drive-peg

V vanes-drive-peg

S sleeves-drive-slot

V vanes-drive-slot 85 lug of the rotor-sleeve 30

87 lug-spring

89 lug-recess in the stator-sleeve 29

90 volute-chamber for collecting pumped coolant from impeller 94 separator

[0157] Figs.17-19

129 stator sleeve

130 movable sleeve

131 cup of the movable sleeve

131end the end cup

132 pump housing

138 thermal actuator

141 sub-entry-chambers

143A apertures

143W windows

145 bars

147 subs-impeller-chamber

149 impeller

178 stem

181 blocker-driver

181S sleeves-blocker-driver

182 guideway on linear sleeve

194 separator

[0158] Figs.20, 21

238 thermal-actuator

229 extra thermal-actuator

231 cups

231X extra cup

241E sub-entry-chamberE

4 IT sub-entry-chamberT

41X sub-entry-chamberX

54X extra temperature-sensing-chamber

94 separator

[0159] Figs.22, 23

29 inner sleeve

330 outer sleeve (stator)

329X,330X supplementary pair of sleeves for closing main flow 338V vanes-thermal-actuator 338S separate thermal-actuator

341 sub-entry-chambers

341H a sub-entry-chamber

347 subs-impeller-chamber

361 radxally-orientatable swirl vanes

370 vanes-actuation-ring

374 modulator-impeller-chamber

392 gear teeth on radial spindles of vanes

394 separator

396 seal between sleeves

397 wave-spring

398 location-ribs for seal

399 O-rings

[0160] Fig.24

420 battery pack

423 heater

425 chiller

429 stator sleeve

430 rotor sleeve

461 swirl-vanes

Claims

Claim 1. A coolant pumping apparatus, wherein:

[2] the apparatus is structured for pumping liquid coolant through a coolant circulation system;

[3] the apparatus includes a fixed housing, a rotary impeller having blades, and a rotary impeller-driver for rotating the impeller ;

[4] the apparatus includes a pump-outlet conduit, for gathering

coolant emerging from the impeller, and for conveying same out of the apparatus and through the system;

[5] the apparatus includes an operable flow-swirl-modulator;

[6] the apparatus includes a modulator-entry chamber and a modulator- impeller chamber;

[7] the modulator-entry chamber is structured to receive coolant

circulating in a main-circuit of the system, and to convey same to the flow-swirl-modulator;

[8] the modulator-impeller chamber is structured to receive a main- impeller-flow of coolant emerging from the modulator and to convey same into the blades of the impeller;

[9] the apparatus is so structured that the flow-swirl-modulator

imparts a rotary-swirl motion, being an angular-velocity vector-component, to the main-impeller-flow of coolant in the modulator-impeller chamber;

[10] the flow-swirl-modulator has the capability, upon being operated in a modulator-orientation mode of movement, to change the magnitude and the rotational sense of the angular-velocity vector-component ;

[11] the apparatus includes respective sub-entry-chambers for receiving coolant flow circulating in plural sub-circuits of the system, being sub-entry-chamber-A in respect of sub- circuit-A, sub-entry-chamber-B in respect of sub-circuit-B, and so on ;

[12] the apparatus includes a subs-impeller-chamber, which is

structured to receive coolant flow emerging from the sub- entry-chambers, and to convey same into the blades of the impeller;

[13] in respect of sub-circuit-A:

[14] (a) the apparatus includes a flow-blocker-A, which separates the sub-entry-chamber-A from the sub-impeller chamber;

[15] (b) the flow-blocker-A is movable in an open/close mode of

movement, between a blocker-open position and a blocker- closed position;

[16] (c) when moved to the blocker-open position, the flow-blocker-A is so positioned as to enable a sub-flow-A of coolant through the flow-blocker-A, from the sub-entry-chamber-A to the subs-impeller chamber;

[17] (d) when moved to the blocker-closed position, the flow-blocker-A is so positioned as to block coolant flow from the sub- entry-chamber-A to the subs-impeller chamber;

[18] in respect of sub-circuit-B :

[19] (a) the apparatus includes a flow-blocker-B, which separates the sub-entry-chamber-B from the sub-impeller chamber;

[20] (b) the flow-blocker-B is movable in an open/close mode of

movement, between a blocker-open position and a blocker- closed position;

[21] (c) when moved to the blocker-open position, the flow-blocker-B is so positioned as to enable a sub-flow-B of coolant through the flow-blocker-B, from the sub-entry-chamber-B to the subs-impeller chamber;

[22] (d) when moved to the blocker-closed position, the flow-blocker-B is so positioned as to block coolant flow from the sub- entry-chamber-B to the subs-impeller chamber;

[23] the apparatus includes a thermal-unit, which includes:

(a) a temperature-sensor;

[24] (b) a movable-element, which is movable responsively to changes in temperature as sensed by the temperature-sensor;

[26] (c) a modulator-driver, which is structured to convert movement of the movable-element into corresponding operation of the flow-swirl modulator, in the modulator-orientation mode of movement ;

[27] (d) a blocker-driver, which is structured to convert movement of the movable-element into corresponding movement of the flow- blocker-A in the open/close mode of movement, and of the flowblocker-B in the open/close mode of movement.

Claim 2. As in claim 1, wherein:

[2] the operable flow-swirl-modulator is an operable set of swirl- vanes ,-

[3] the apparatus is so structured that the swirl-vanes impart the said rotary helical swirl motion to the main-impeller-flow of coolant passing through the modulator-impeller chamber;

[4] the swirl-vanes are orientatable, as a set, in unison, in a vanes- orientation mode of movement, between a flow-reducing orientation of the swirl-vanes relative to the impeller, and a flow-boosting orientation of the swirl-vanes relative to the impeller;

[5] the flow-blocker-A and the flow-blocker-B are incorporated into a pair of sleeves;

[6] the open/close mode of movement of the flow-blocker-A is an

open/close mode of movement of the sleeves, between a sleeves-open position and a sleeves-closed position;

[7] in the sleeves-open position, an aperture-A in one sleeve

coincides with a window-A in the other, to the extent that the sub-flow-A of coolant is enabled, from the sub-entry- chamber-A through to the modulator-impeller chamber;

[8] in the sleeves-closed position, the aperture-A in the one sleeve coincides with a bar-A in the other sleeve, whereby flow of coolant through the sleeves is blocked;

[9] the modulator-driver is structured to convert movement of the

movable-element into corresponding movement of the vanes, in the vanes-orientation mode of movement;

[10] the blocker-drive is structured to convert movement of the

movable-element into corresponding relative movement of the sleeves, in the open/close mode of movement.

Claim 3. As in claim 2, wherein the arrangement of the apertures, windows, and bars, in the sleeves, is such that, when the sleeves move relatively, the sub-entry-chamber-A opens and closes with respect to the modulator-impeller chamber at different

temperatures from those at which the sub-entry-chamber-B opens and closes .

Claim 4. As in claim 2, wherein the separate sub-entry-chamber-A, -B are positioned in respective sectors arranged around the

circumference of the outer sleeve.

Claim 5. As in claim 21, wherein:

[2] the sleeves are arranged one inside the other;

[3] at least the movable-sleeve is of annular form;

[4] at least at the interface between the two sleeves, at least the movable-sleeve is substantially right-cylindrical;

[5] the apertures in the movable sleeve are located in a wall of the movable sleeve.

Claim 6. As in claim 4, wherein the inner-sleeve is a movable-sleeve , the outer-sleeve being a stator-sleeve .

Claim 7. As in claim 1, wherein:

[2] the apparatus includes three tiers, being a bottom tier, a middle tier, and a top tier;

[3] the bottom tier contains the impeller and the pump-outlet conduit;

[4] the middle tier contains the modulator-entry chamber and the set of swirl-vanes;

[5] the top tier contains the sub-entry-chambers and the pair of

sleeves ;

[6] the modulator-impeller-chamber conveys the main-impeller-flow of coolant emerging from the set of vanes in the middle tier into the blades of the impeller in the bottom tier;

[7] the sub-impeller-chamber conveys the sub-flows of coolant emerging from the sleeves in the top tier into the blades of the impeller in the bottom tier.

Claim 8. As in claim 7, wherein the sub-impeller chamber is so arranged in the apparatus as to convey the sub-flows through the middle tier, to the impeller.

Claim 9. As in claim 7, wherein:

[2] the movable-element of the thermal unit is located between the top tier and the middle tier;

[3] the blocker-driver is located in the top tier, and the modulator- driver in the middle tier.

Claim 10. As in claim 8, wherein:

[2] the movable-sleeve is a rotor-sleeve, which is mounted for

rotation relative to the stator-sleeve;

[3] at the interface between the rotor-sleeve and the stator-sleeve, the diameter of the rotor-sleeve is at least double the axial height of the rotor-sleeve.

Claim 11. As in claim 1, wherein the temperature-sensor and the movable element of the thermal-unit are components of a wax-element thermal-actuator .

Claim 12. As in claim 1, wherein:

[2] the temperature-sensor is arranged to sense temperature of coolant passing through a temperature-sensing chamber of the apparatus ; and

[3] the movable-element is movable responsively to changes in the

coolant-temperature as sensed by the temperature-sensor.

Claim 13. As in claim 12, wherein:

[2] one of the sleeves is a movable-sleeve, and is mounted in the

apparatus for rotation relative to the stator-sleeve;

[3] the blocker-driver is so structured as to be effective to convert movement of the movable element into movement of the rotor- sleeve;

[4] the open/close mode of movement of the movable-sleeve occurs when the movable-element moves responsively to a change in temperature of coolant passing through the temperature- sensing chamber.

Claim 14. As in claim 12, wherein:

[2] the temperature-sensing-chamber includes a modulator-sensing- chamber and a blocker-sensing-chamber;

[3] the temperature-sensor includes a vanes-sensor and a sleeves- sensor, which are located respectively in the modulator- sensing-chamber and blocker-sensing chamber;

[4] the movable-element includes a modulator-movable-element and a blocker-movable-element ;

[5] the vanes-movable-element moves responsively to changes in

temperature of coolant passing through the modulator-sensing chamber, and the blocker-movable-element moves responsively to changes in temperature of coolant passing through the blocker-sensing chamber.

Claim 15. As in claim 1, wherein:

[2] the main-impeller-flow enters the impeller basically as a

helically-swirling annulus, the annulus having a helical swirl velocity;

[3] the helical swirl motion of the annulus is the resultant of (a) an angular-velocity vector-component induced in the main- impeller-flow upon passing through the modulator, and (b) an axial-velocity vector-component induced in the main- impeller-flow upon passing through the modulator-impeller chamber ;

[4] the main-impeller-flow, as it enters the blades of the impeller, is substantially co-axial with the axis of the impeller;

[5] the sub-flow has an overall translational-velocity vector that is substantially coaxial with the axis of the impeller;

[6] as the sub-flow and the main-impeller-flow enter the impeller, the axial sub-flow lies at the centre of the impeller; and

[7] the axial sub-flow is surrounded by the annular helically-swirling main-impeller-flow.

16. As in claim 1, wherein the apparatus is so structured and arranged that :

all coolant circulating in all the sub-circuits enters the

impeller from the sub-impeller chamber ; only the main-impeller-flow, being coolant that has passed through the swirl -vanes, can enter the impeller through the

modulator-impeller chamber;

apart from the main-impeller-flow with its angular-velocity

component, no significant flow of coolant can enter the impeller with a significant velocity component, whether translational or rotational, other than an axial-velocity component that is coaxial with the axis of the impeller.

17. As in claim 1, wherein the apparatus includes a main-subs flow-separator, which keeps the rotary-swirling annular main- impeller-flow in the modulator-impeller chamber physically separated from the subs-impeller-flow in the subs-impeller chamber .

Claim 18. As in claim 1, wherein:

[2] the main-subs-flow-separator keeps the main-flow in the modulator- impeller-chamber separate from the subs-impeller-flow in the subs-impeller chamber, until both flows are on the point of entering the impeller;

[3] the subs-impeller-chamber containing the subs-impeller-flow is located inside the main-subs-flow-separator;

[4] the subs-impeller-chamber containing the rotary-swirling annular main-impeller-flow is located outside the flow-separator; and

[5] the main-subs-flow-separator extends sufficiently close to the impeller that the subs-impeller-flow substantially does not interfere with, and does not significantly affect, the angular-velocity vector-component of the main-impeller-flow as the main-impeller-flow enters the blades of the impeller.

Claim 19. As in claim 1, wherein the movable-sleeve is mounted for

linear movement relative to the stator-sleeve .

Claim 20. The combination of the apparatus of claim 1 with an

automotive engine coolant circulation system, which includes a radiator, the radiator being a component of the main-circuit.