Thermal control of flowrate in engine coolant system

Abstract

An impeller pump with thermostatically adjustable swirl-vanes, in use as an automotive engine-driven coolant pump. Flow variation is controlled by varying the orientation of the swirl-vanes. A change in orientation is effected by a thermal driver, e.g a wax-type thermostat, which senses coolant temperature. The swirl-vanes boost the flowrate when the coolant is hot, and decrease it when the coolant cools. The swirl-vanes are mounted for pivoting, and are located just upstream from the pump impeller. The traditional engine-thermostat function is provided inside the pumping-chamber, in that the swirl-vanes can be operated to close off a port to the engine radiator. The thermal driver opens the radiator-port as the coolant goes from Cold to Warm; as the coolant goes from Warm to Hot, the thermal driver operates the swirl-vanes from flow-reduce to flow-boost.

1 . A coolant pumping apparatus, wherein: 
 the apparatus is structured for pumping liquid coolant around the coolant circulation circuit of an engine and associated radiator;    the apparatus includes a fixed housing, having walls which define a pumping-chamber;    the apparatus includes a pump impeller, having blades, and includes a rotary-driver for rotating the impeller;    the pump impeller lies inside the pumping-chamber, and is effective to pump coolant through the chamber;    the apparatus includes a radiator-port, for making coolant-conducting communication between the pump impeller and the radiator;    the apparatus includes a radiator-port-closer;    the radiator-port-closer is mechanically movable in a port-losure mode of movement, being movement between a port-open position with respect to the said radiator-port, and a port-closed position;    the apparatus includes a rad-port-thermal-unit, which includes: 
 a coolant-temperature sensor;  
 a fixed-element and a thermally-movable-element, the thermally-movable-element being movable relative to the fixed-element in response to changes in the coolant-temperature sensed by the sensor;  
 a rad-port-driver, which is so structured as to convert movement of the thermally-movable-element of the rad-port-thermal-unit into corresponding movement of the radiator-port-closer in the port-closure mode;  
   the apparatus includes a set of swirl-vanes;    the swirl-vanes are so arranged in relation to the impeller as to impart a rotary swirl motion to the flow of coolant passing through the impeller;    the apparatus includes a vane-mounting-structure, having a vane-orientation-guide;    the swirl-vanes are mechanically movable in a vane-orientation mode of movement, their movement constrained by the vane-orientation-guide, being movement between a flow-reducing orientation of the swirl-vanes relative to the rotary impeller, and a flow-boosting orientation;    the vane-orientation-guide is so structured as to constrain the swirl-vanes of the set all to move in unison with each other;    the apparatus includes a swirl-vane-thermal-unit, which includes: 
 a coolant-temperature sensor;  
 a fixed-element and a thermally-movable-element, the thermally-movable-element being movable relative to the fixed-element in response to changes in the temperature sensed by the sensor;  
 a swirl-vane-driver, which is so structured as to convert movement of the thermally-movable-element of the swirl-vane-thermal-unit into corresponding movement of the swirl-vanes in the vane-orientation mode of movement;  
   and the set of swirl-vanes, the radiator-port, and the radiator-port-closer, are located inside the pumping-chamber.    
   
   
       2 . Apparatus of  claim 1 , wherein the set of swirl-vanes, the radiator-port, and the radiator-port-closer, are located inside the pumping-chamber in the following sense: 
 in the apparatus, the flow of coolant passing through the impeller has a minimum cross-sectional area of min-A sq.mm, the square root of which is min-D mm;    the pumping-chamber is the chamber defined by those portions of the walls of the fixed housing that lie within about 2×min-D millimetres of the blades of the impeller;    at least a portion of the radiator-port, at least a portion of the radiator-port-closer, and at least a portion of the swirl-vanes, are located inside the pumping-chamber, so defined.    
   
   
       3 . Apparatus of  claim 1 , wherein: 
 the thermally-movable-element of the rad-port-thermal-unit and the thermally-movable-element of the swirl-vane-thermal-unit are combined in a structurally-unitary common thermally-movable-element;    the swirl-vane-driver and the rad-port-driver are so structured as to convert movement of the common thermally-movable-element into corresponding movements of both the radiator-port-closer in the port-closure mode, and the swirl-varies in the vane-orientation mode of movement.    
   
   
       4 . Apparatus of  claim 3 , wherein the radiator-port-closer is an axial-slide valve.  
   
   
       5 . Apparatus of  claim 1 , wherein: 
 the radiator-port-closer and the set of swirl-vanes are combined in a single structural unit termed the combined rad-port-closer/swirl-vanes;    the thermally-movable-element of the rad-port-thermal-unit and the thermally-movable-element of the swirl-vane-thermal-unit are combined in a structurally-unitary common thermally-movable-element;    the rad-port-driver and the swirl-vane-driver are combined in a structurally-unitary common-driver;    the common-driver is so structured as to convert movement of the common thermally-movable-element into corresponding movement of the combined rad-port-closer/swirl-vanes, being movement both in the port-closure mode and in the vane-orientation mode;    
   
   
       6 . Apparatus of  claim 1 , wherein: 
 the radiator-port-closer and the set of swirl-vanes are combined in a single structural unit termed the combined rad-port-closer/swirl-vanes;    the rad-port-driver and the swirl-vane-driver are so structured as to convert movement both of the thermally-movable-element of the rad-port-thermal-unit and of the thermally-movable-element of the swirl-vane-thermal-unit into corresponding movement of the combined rad-port-closer/swirl-vanes, being movement both in the port-closure mode and in the vane-orientation mode.    
   
   
       7 . Apparatus of  claim 6 , wherein: 
 the apparatus includes a by-pass port, through which coolant can by circulated through the engine by the impeller;    the swirl-vanes, when closed, close off the radiator-port, but do not close off the by-pass port, whereby coolant can still circulate through the engine even when the radiator-port is completely closed.    
   
   
       8 . Apparatus of  claim 1 , wherein the swirl-vanes are located immediately upstream of the impeller blades.  
   
   
       9 . Apparatus of  claim 1 , wherein: 
 the swirl-vanes are pitched around a pitch-circle, and the pitch-circle is concentric with the axis of the impeller;    the swirl-vane-driver includes a swirl-vane-actuating-ring, which is guided for rotation co-axially with the pitch-circle, and which is driven to rotate by the said movement of the thermally-movable-element of the swirl-vane-thermal-unit;    the arrangement of the apparatus is such that rotation of the swirl-vane-actuating-ring is effective to produce corresponding re-orientation of the swirl-vanes; and    the swirl-vanes occupy at least sixty percent of the circumference of the pitch-circle.    
   
   
       10 . Apparatus of  claim 1 , wherein the swirl-vanes are arranged to lie in contact against each other to close off the radiator-port.  
   
   
       11 . Apparatus of  claim 1 , wherein the rotary-driver includes a mechanical connection to the engine, whereby the rotary impeller is driven at a speed proportional to engine speed.  
   
   
       12 . Apparatus of  claim 1 , wherein the swirl-vane-driver and the rad-port-driver are so structured that: 
 the radiator-port-closer substantially cannot move, in the port-closure mode, other than in correspondence with movement of the rad-port-driver; and    the swirl-vanes substantially cannot move, in the vane-orientation mode, other than in correspondence with movement of the swirl-vane-driver.    
   
   
       13 . Apparatus of  claim 5 , wherein: 
 the common-driver is so structured that movement of the thermal-driver, responsive to an increase in the coolant-temperature from cold to hot, is effective:—
 to move the radiator-port-closer, in the said port-closure mode, away from the radiator-port-closed position towards the radiator-port-open position; and also  
 to move the swirl-vane, in the said vane-orientation mode, away from the flow-reducing orientation towards the flow-boosting orientation.  
   
   
   
       14 . Apparatus of  claim 13 , wherein: 
 the common-driver has an overall range of movement, from cold to hot;    the common-driver is so structured that:—
 the movement of the radiator-port-closer, in the port-closure mode, towards the radiator-port-open position, occurs as a radiator-port-closer portion of the overall range of movement of the common-driver; and  
 the movement of the swirl-vane, in the vane-orientation mode, towards the flow-boosting orientation, occurs as a vane-orientation portion of the overall range of movement of the common-driver.  
   
   
   
       15 . Apparatus of  claim 13 , wherein the common-driver is so structured that: 
 the radiator-port-closer portion of the overall range of movement of the common-driver occurs when the temperature of the coolant is towards the cold end of the range;    the vane-orientation portion of the overall range of movement of the common-driver occurs when the temperature of the coolant is towards the hot end of the range.    
   
   
       16 . Apparatus of  claim 13 , wherein the common-driver is so structured that: 
 there is no overlap between the radiator-port-closer portion of the overall range of movement of the common-driver and the vane-orientation portion;    in that the radiator-port-closer portion is finished, the radiator-port being then open to full flow of coolant therethrough, substantially before the vane-orientation portion commences.    
   
   
       17 . Apparatus of  claim 13 , wherein the common-driver is so structured that: 
 over a unison-portion of the overall range of movement of the common-driver, there is overlap between the radiator-port-closer portion of the overall range of movement of the common-driver, and the vane-orientation portion;    in that, over the unison-portion, the common-driver constrains the swirl-vane and the radiator-port-closer to move together, in unison.    
   
   
       18 . Apparatus of  claim 13 , wherein the common-driver is so structured that, over a lost-motion portion of the overall range of movement of the common-driver, movement of the common-driver produces corresponding movement of one of either the radiator-port-closer or the swirl-vane, while the other does not undergo corresponding movement.  
   
   
       19 . Apparatus of  claim 18 , wherein the common-driver is so structured that: 
 over a cold-lost-motion portion of the overall range of movement of the common-driver, movement of the common-driver produces corresponding movement of the radiator-port-closer in the port-closure mode, while the swirl-vane does not undergo corresponding movement in the vane-orientation mode;    over a hot-lost-motion portion of the overall range of movement of the common-driver, movement of the common-driver produces corresponding movement of the swirl-vane in the vane-orientation mode, while the radiator-port-closer does not undergo corresponding movement in the port-closure mode.    
   
   
       20 . Apparatus of  claim 1 , wherein the coolant-temperature-sensor of the rad-port-thermal-unit is physically separate from the coolant-temperature-sensor of the swirl-vane-thermal-unit.  
   
   
       21 . Apparatus of  claim 20 , wherein the coolant-temperature-sensor of the rad-port-thermal-unit and the coolant-temperature-sensor of the swirl-vane-thermal-unit are so located as to measure coolant temperatures at different locations of the coolant circulation circuit.  
   
   
       22 . Apparatus of  claim 3 , wherein: 
 the rad-port-thermal-unit and the swirl-vanes-thermal-unit are combined in a structurally-unitary combined thermal-unit;    the combined thermal-unit comprises a mechanical thermostat, having a temperature-sensitive bulb which expands/contracts in accordance with the temperature of the coolant, and a movable-element of the combined-thermal-unit comprises a movable stem of the thermostat.    
   
   
       23 . Apparatus of  claim 22 , wherein: 
 a rate of the thermostat comprises the movement of the stem, in length units, per degree change in temperature of coolant, and:    the thermostat has two different rates, being an initial-opening rate, and a warmed-up rate;    the initial-opening rate is the rate of movement of the stem that obtains upon the coolant reaching a warmed-up temperature, to move the radiator-port closer from the closed to the open position.    
   
   
       24 . Apparatus of  claim 23 , wherein the warmed-up rate is in two parts, being a cooler part and a hotter part of the warmed-up temperature range, and the rate in the hotter part is greater than the rate in the cooler part.  
   
   
       25 . Apparatus of  claim 1 , wherein: 
 the swirl-vanes are situated immediately adjacent to, and upstream of, the impeller; and    the radiator-port is situated upstream of the swirl-vanes.    
   
   
       26 . Apparatus of  claim 1 , wherein: 
 the impeller has a set of primary blades and a set of secondary blades;    the impeller is so shaped and configured that coolant emerging from the primary blades has such direction and velocity as to be partially deflected away from the entrances of the secondary blades;    whereby, when the impeller is rotating at slow rotational speeds, a relatively large proportion of the flow emerging from the primary blades enters the secondary blades, but, when the impeller is rotating at high speeds, only a relatively small proportion of the flow emerging from the primary blades enters the secondary blades.    
   
   
       27 . Apparatus of  claim 26  wherein the secondary blades are predominantly radial.  
   
   
       28 . Apparatus of  claim 26 , wherein the flow has to turn around a promontory in order to enter the secondary blades, and the flow is so directed that the faster the flow, the less its inclination to round the promontory and enter the secondary blades.  
   
   
       29 . Apparatus of  claim 1 , wherein: 
 the circuit includes a heater, and the walls of the pumping chamber include a heater-port, through which coolant from the heater can pass through the pumping chamber;    the apparatus includes a heater-port-closer, which is effective to close the heater-port in accordance responsively to the temperature of the coolant.    
   
   
       30 . Apparatus of  claim 2 , wherein the set of swirl-vanes, the radiator-port, and the radiator-port-closer, are located substantially wholly inside the pumping-chamber, so defined.  
   
   
       31 . A coolant pumping apparatus, wherein: 
 the apparatus is structured for pumping liquid coolant around the coolant circulation circuit of an engine and associated radiator;    the apparatus includes a fixed housing, having walls which define a pumping-chamber;    the apparatus includes a pump impeller, having blades, and includes a rotary-driver for rotating the impeller;    the rotary-driver includes a mechanical connection to the engine, whereby the rotary impeller is driven at a speed proportional to engine speed;    the impeller has a set of primary blades and a set of secondary blades;    the impeller is so shaped and configured that coolant emerging from the primary blades has such direction and velocity as to be partially deflected away from the entrances of the secondary blades;    whereby, when the impeller is rotating at slow rotational speeds, a relatively large proportion of the flow emerging from the primary blades enters the secondary blades, but, when the impeller is rotating at high speeds, only a relatively small proportion of the flow emerging from the primary blades enters the secondary blades;    the secondary blades are predominantly radial;    the structure of the apparatus is such that the flow has to turn around a promontory in order to enter the secondary blades, and the flow is so directed that the faster the flow, the less its inclination to round the promontory and enter the secondary blades.    
   
   
       32 . A coolant pumping apparatus, wherein: 
 the apparatus is structured for pumping liquid coolant around the coolant circulation circuit of an engine and associated radiator;    the apparatus includes a fixed housing, having walls which define a pump chamber;    the apparatus includes a pump impeller, having blades, and includes a rotary-driver for rotating the impeller;    the pump impeller lies inside the pump chamber, and is effective to pump coolant through the chamber;    the walls of the pump chamber include a radiator-port, for making coolant-conducting communication between the pump chamber and the radiator;    the apparatus includes a radiator-port-closer;    the radiator-port-closer is mechanically movable in a port-closure mode of movement, being movement between a port-open position with respect to the said radiator-port, and a port-closed position;    the apparatus includes a swirl-vane, located inside the pump chamber;    the swirl-vane is so arranged in relation to the impeller as to impart a rotary swirl motion to the flow of coolant passing through the impeller;    the apparatus includes a vane-mounting-structure, having a vane-orientation-guide;    the swirl-vane is mechanically movable in a vane-orientation mode of movement, its movement constrained by the vane-orientation-guide, being movement between a flow-reducing orientation of the swirl-vane relative to the blades of the rotary impeller, and a flow-boosting orientation;    the apparatus includes a thermal-unit, having a coolant-temperature sensor;    the thermal-unit includes a fixed-element and a movable-element;    the movable-element is movable relative to the fixed-element, in response to changes in the coolant-temperature sensed by the sensor;    the apparatus includes a thermal-driver;    the thermal-driver is a mechanically-unitary structure, which is so structured as to convert movement of the movable-element of the thermal-unit into both movement of the radiator-port-closer in the port-closure mode, and movement of the swirl-vane in the vane-orientation mode.