Patent Publication Number: US-8991339-B2

Title: Multi-zone vehicle radiators

Description:
TECHNICAL FIELD 
     The present disclosure relates to thermal management systems for a vehicle powertrain, especially radiators. 
     BACKGROUND 
     Conventional vehicle powertrains are equipped with thermal management systems to control the temperature of powertrain components during vehicle operation. For example, vehicles commonly have a radiator in thermal communication with the engine to remove heat therefrom. There are also heat exchangers that warm and/or cool automatic transmission fluid when needed. It is desirable to have a multiple zone radiator with various temperature zones configured to separately cater to the thermal demands of different powertrain components (e.g., one zone for the engine and another zone for automatic transmission fluid). 
     U.S. Pat. No. 7,464,781 to Guay et al. titled “Three-Wheeled Vehicle Having a Split Radiator and an Interior Storage Compartment” presents the use of two separate radiators to accommodate vehicle packaging restraints. The &#39;781 patent teaches that the radiators can be arranged in series or in parallel. However, the radiators are housed in different locations and said radiators appear to be dedicated to engine oil cooling only. 
     It is more beneficial to have a single radiator with designated sections or zones for different cooling temperatures. A single radiator unit generally requires less parts, assembly time and packaging space and would result in less weight for the vehicle. The utilization of a single radiator can also yield significant undesirable results. For example, the temperature differential between zones can cause unwanted structural strain on the radiator housing. Commonly, when coolant is flowing through one zone but not flowing in an adjacent zone the radiator housing can be subject to unwanted strain. Radiator channels can thermally expand at a higher rate in zones where coolant is flowing than the channels without coolant flowing. 
     One solution available in the automotive industry is the use of an aperture (or orifice) in a baffle which divides zones of the radiator. The presence of the orifice allows flow from one zone to another whenever the zone is flowing while the other zone otherwise would not. This solution may reduce thermal strain but also reduces the cooling benefits of a multiple zone radiator with lower temperature zone. The zone intended to run colder tends to leak into the adjacent zone, which has the tendency of increasing its temperature as well as reducing flow intended for a downstream heat exchanger. Therefore, it is desirable to have a multiple zone vehicle radiator that reduces unwanted strains on the radiator housing during operation without compromising outlet temperature and flow to downstream heat exchangers. 
     SUMMARY 
     The present disclosure addresses one or more of the above-mentioned issues. Other features and/or advantages will become apparent from the description which follows. 
     One exemplary embodiment relates to a multiple zone vehicle radiator, including: a housing; a first zone included in the housing; a second zone included in the housing; a baffle between the first and second zone, located in an outlet manifold of the housing; and a zone modifier configured to regulate coolant distribution between the first zone and second zone according to predetermined conditions. 
     Another exemplary embodiment pertains to a thermal management system, having: a multiple-zone radiator; a thermostat configured to control coolant flow from the radiator to an engine; and a zone modifier configured to regulate coolant distribution between the first zone and second zone of the radiator according to predetermined conditions. 
     Another exemplary embodiment relates to a thermal management system, including: a multiple-zone radiator; a jumper line between outlet lines of a first zone of the radiator and a second zone of the radiator; a thermostat configured to control coolant flow from the radiator to an engine; and a zone modifier in the jumper line configured to regulate coolant distribution between outlet lines from a first zone and a second zone of the radiator according to predetermined conditions. 
     One advantage of the present disclosure is that it teaches the use of a zone modifier to avoid situations in which one thermal zone is flowing at a significantly different rate than the other zone thus significantly avoiding unwanted strain on the radiator caused by thermal differentials, without reducing coolant flow or raising temperature of coolant intended for downstream heat exchangers when both zones are flowing at more similar rates. 
     The invention will be explained in greater detail below by way of example with reference to the figures, in which the same reference numbers are used in the figures for identical or essentially identical elements. The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. In the figures: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic depiction of a vehicle powertrain with an exemplary powertrain thermal management system. 
         FIG. 2  is a front view of an exemplary multi-zone radiator compatible with the thermal management system shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of an exemplary check valve installed in a baffle between zones in the radiation of  FIG. 2 , shown at circle  3 . 
         FIGS. 4 and 5  illustrate cross-sectional views of another exemplary check valve in opened and closed positions, respectively. 
         FIG. 6  is a schematic depiction of a vehicle powertrain with another exemplary powertrain thermal management system. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, wherein like characters represent examples of the same or corresponding parts throughout the several views, there are shown various powertrain thermal management systems with radiators having multiple thermal zones. The radiators are configured with more than one thermal zone, enabling the radiators to have a hot section and a cold section. Each thermal management system has a zone modifier to selectively enable coolant flow between zones when needed. For example, if the pressure differential between the two zones exceeds a predetermined threshold zone modifiers are configured to pass coolant from the high pressure zone to the low pressure zone. 
     Now turning to  FIG. 1  there is shown therein a schematic depiction of a vehicle powertrain having an exemplary powertrain thermal management system  10 . The powertrain includes a gas engine  20  (or internal combustion engine) and an automatic transmission  30 . Any type of engine can be used with the thermal management system including, but not limited to inline engines, v-type engines, Wankels or diesel engines. Also, any of transmission can be used with the thermal management systems, including but not limited to, five- to nine-speed transmissions, continuously variable transmissions, electrically variable transmissions, dual-clutch transmissions, or manuals. Alternately, a power transfer unit or any other device using coolant for cooling can be assumed in place of transmission  30 . The illustrated embodiment includes an automatic transmission and the thermal management system  10  is configured to control the temperature of automatic transmission fluid. 
     As shown in  FIG. 1 , the engine  20  is connected to a heater core  40  that supports the vehicle heating ventilation and cooling system (or HVAC). Any type of heater core can be used. The engine  20  is configured to be cooled by a vehicle radiator  50 . Line  120  delivers coolant from the engine to the radiator  50 . Radiator  50  is a multiple zone radiator having two zones  60 ,  70  in this embodiment. Radiator  50  has an inlet manifold  65  and an outlet manifold  75 . The inlet manifold  65  directs coolant to both zones  60 ,  70 . The outlet manifold  75  includes a baffle  80  which divides the zones where each zone will discharge through a different outlet in the radiator  50 . Zone  1 ,  60 , is dedicated to engine cooling, where coolant flow is intended to be relatively high to improve engine cooling. Zone  2 ,  70 , will also provide coolant to the engine but the flow rate in this embodiment is lower than the flow rate in Zone  1  in order to achieve a lower outlet temperature. Said lower outlet temperature is advantageous to cooling other driveline components using oil to coolant heat exchangers. Baffle  80  substantially prevents fluid travel between the zones. Baffle  80  includes a zone modifier  90  that selectively enables fluid distribution between zones. 
     As shown, the engine  20  is linked to Zone  1 ,  60 , which discharges coolant through the outlet manifold  75  to line  95 . Line  95  links to line  110  which returns coolant to a thermostat  100 . Thermostat  100  in this embodiment is a dual-stage continuous regulator valve configured to regulate engine inlet temperature, which has the effect of closing under operating conditions where the engine  20  does not require cooling from the radiator  50 . When thermostat  100  is closed Zone  1 ,  60 , is not providing coolant to the engine  20 . At the same time, since there is no flow in the radiator Zone  1 ,  60 , approaches ambient temperature. Zone  2  continues operating at a higher temperature when valve  140  is providing flow to the heat exchanger  130 . The pressure in Zone  1 ,  60 , increases to be higher than Zone  2 ,  70 , in the outlet manifold,  75 , which presents the opportunity for a zone modifier  90  to enable flow from Zone  1  to Zone  2 . This arrangement results in less thermal strain to the radiator housing. In this embodiment, zone modifier  90  is actuated under conditions where thermostat  100  is closed and valve  140  provides coolant to heat exchanger  130  thus producing a substantial pressure differential between the two zones  60 ,  70 . Zone modifier  90  is preferably a check valve, allowing flow from Zone  1 ,  60 , to Zone  2 ,  70 , when Zone  1  runs at a predetermined higher pressure. Zone modifier  90  does not allow flow from Zone  2  to Zone  1  when the predetermined pressure differential is unmet. When the thermostat is barely open, similar function is expected. 
     Also shown in  FIG. 1 , line  85  directs coolant from Zone  2 ,  70 , to valve  140 . Valve  140  in this embodiment is a dual-stage diverter valve. Valve  140  can direct coolant to line  160  or  150  depending on position of the valve. Line  150 , connects valve  140  to a heat exchanger,  130 . Line  180  fluidly connects heat exchanger  130  to the heater core return line, returning coolant to the engine. When the transmission fluid requires cooling, valve  140  provides coolant to the transmission heat exchanger  130  through line  150 . When the transmission does not require cooling, valve  140  directs Zone  2 ,  70 , coolant directly to line  160 , which is linked to line  110 . In this embodiment, heat exchanger  130  is a transmission fluid cooler but can be a power transfer unit fluid cooler as well. In other embodiments heat exchanger  130  is an engine oil cooler or other alternative purpose cooler. In other embodiments, the heat exchanger  130  can be integrated with the transmission  30  or other device requiring use of coolant for cooling. 
     Thermal management system  10  as shown in  FIG. 1 , includes microcontroller  190  configured to govern control valve  140  according to powertrain operating conditions. Microcontroller can be incorporated in other vehicle control modules including but not limited to the engine control unit, transmission control unit, battery control module or vehicle control module. Microcontroller can be any sort of computer or control circuit such as a computer having a central processing unit, memory (e.g., RAM and/or ROM), and associated input and output buses. The microcontroller can be application-specific integrated circuits or may be formed of other logic devices. 
     Now with reference to  FIG. 2 , there is shown therein a radiator  200  that is compatible with a thermal management system, e.g.,  10  as shown in  FIG. 1 . In  FIG. 2 , a front, partial cross-sectional view of the radiator  200  is shown. The radiator  200  includes an inlet and outlet manifold,  210  and  220 , respectively that define the radiator housing. Several channels  240  pass coolant from the inlet manifold  210  to the outlet manifold  220  while dropping temperature of the coolant. A first zone  260  is defined as the lower section of the radiator  200 . A second zone  250  is defined as the upper section of the radiator  200 . Manifold  220  includes an outlet  265  for Zone  1  and an outlet  255  for Zone  2 . Baffle  270  is included in the manifold  220  and divides the outlet manifold  220 . Baffle  270  includes an aperture  280  into which a zone modifier (e.g.,  300  as discussed with respect to  FIG. 3 ) is included. Aperture  280  houses a zone modifier (examples of which are shown as  300 ,  400  and  500  in  FIGS. 3 ,  4  and  5 , respectively) which can selectively act as a second outlet spigot for Zone  1 ,  260 , while preventing the aperture from being a second outlet for Zone  2 . In this embodiment, Zone  2 ,  250 , flows fluid at a lower velocity than Zone  1 ,  260 , in order to lower the outlet temperature of coolant from Zone  2 . In another embodiment, the positions of the zones are interchanged. 
       FIG. 3  illustrates the zone modifier  300  used with the radiator  200  of  FIG. 2 . Zone modifier  300  is positioned in the baffle  270  between Zones  1  and  2 . In  FIG. 3 , the baffle  270  shown in  FIG. 2  is partially shown in cross-section. Zone modifier  300  is fitted in the aperture  280 . When Zone  2  is at a higher pressure than Zone  1 , the zone modifier will not allow coolant to flow between zones. When Zone  1  is at a higher pressure than Zone  2 , the zone modifier will allow flow from Zone  1  to Zone  2 . As shown in  FIG. 1 , one incident causing undesirable thermal strain is when the engine thermostat,  100 , is closed or significantly reducing flow across Zone  1 ,  60 , while diverter valve  140  actuates to direct Zone  2 ,  70 , flow to heat exchanger  130 . This situation will result in a pressure differential between Zone  1  and Zone  2  that will actuate the zone modifier  300  to pass flow from Zone  1  to Zone  2 , which will increase flow in Zone  1 , increasing temperature of the channels in Zone  1  to be more similar to Zone  2 , minimizing thermal strain. 
     The zone modifier  300  shown in  FIG. 3  is a spring loaded ball check valve (or pressure relief valve). Check valve  300  includes a retention feature  310  as an interface with the aperture  280  in baffle  270 . In other embodiments, other retention features are incorporated in the check valve. A ball  320  is held in position by spring  330  with respect to the inlet side of the valve. The spring constant is designed or tuned to enable the check valve to open when the pressure differential between Zone  1  and Zone  2  exceeds a predetermined threshold (e.g., 3 psi). Alternatively, the spring can be omitted if the desired pressure differential is zero psi. 
     Now turning to  FIGS. 4 and 5  there is shown an alternative zone modifier  400  for use in a multiple zone radiator.  FIG. 4  illustrates the zone modifier  400  in a closed position. Zone  1  on the lower side of the baffle  410  is designated as the hot side of the radiator. Zone  2  on the upper side of the baffle  410  is designated as the cooler side of the radiator. Zone modifier  400  is a swing check valve that includes a flexible flap or flange  420  attached to one side of the baffle  410  via a rivet  430 . Other attachment methods can be used (e.g., welds, nails, clamps, adhesives or staples). Flap  420  substantially covers an aperture  440  formed in the baffle  410  between the two zones. As previously mentioned, check valve  300  (or zone modifier  400  as shown in  FIGS. 4-5 ) closes off flow between Zone  1  and Zone  2  when the pressure in Zone  2  is higher than the pressure in Zone  1 . When the pressure in Zone  1  is sufficiently higher than Zone  2 , outlet tank pressure in Zone  1  will push thru the aperture and lift the rubber flap to flow to low temp tank (or Zone  2 ). Flap  420  rotates about the attachment point, as shown in the open position of  FIG. 5 . 
     In this embodiment, flap  420  is composed of rubber. In other embodiments, flap  420  is composed of other materials (e.g., aluminum, copper, or other polymers). The elasticity of flap is designed to enable the zone modifier  400  to open when the pressure differential between Zone  1  and Zone  2  exceeds a predetermined threshold (e.g., 3 psi). In another embodiment, the zone modifier is a diaphragm check valve. 
     Another alternative embodiment of a zone modifier  500  is shown and discussed with respect to  FIG. 6 . As shown, a zone modifier  500  does not have to be incorporated in a baffle between sections but can be located outside of the radiator.  FIG. 6  shows an alternate location for zone modifier  500 . Zone modifier  500  includes a check valve  510  included in lines on the outlet end of Zone  2 ,  520 . A T-fitting is included in outlet line  530 . Jumper line  540  is added between the outlet lines of Zones  1  and  2  ( 610  and  530 , respectively) with the check valve  510  included in the line. 
     As shown in  FIG. 6 , an engine  560  is connected to a heater core  570  that supports the vehicle heating ventilation and cooling system (or HVAC). Radiator  580  is a multiple zone radiator having two sections in this embodiment. Zone  1 ,  550 , typically operates at a higher temperature than Zone  2 ,  520 . In this embodiment, Zone  1 ,  550 , is dedicated to engine cooling; Zone  2 ,  520 , supports transmission fluid cooling as previously discussed. Zones  1  and  2  ( 550  and  520 ) are separated by baffle  590 . As shown, the engine  560  is linked to radiator  580 . A thermostat  600  is included between the engine  560  and radiator  580  in line  610 . Thermostat  600  is a continuous dual-stage regulator valve. 
     Transmission fluid heat exchanger  575 , shown in the schematic of  FIG. 6 , is selectively in thermal communication with Zone  2 ,  520 , of the radiator  580 . Zone  2 ,  520 , is designed to run significantly cooler than Zone  1 ,  550 . Between Zone  2  of the radiator  580  and the transmission fluid warmer is a control valve  620 . Control valve  620  is a dual-stage diverter valve. When the transmission fluid requires cooling, valve  620  provides coolant to the transmission heat exchanger  575  through line  630 . When the transmission does not require cooling, valve  620  directs Zone  2 ,  520 , coolant directly to Zone  1  outlet line  610 . In this embodiment, heat exchanger  575  is a transmission fluid cooler but can be a power transfer unit fluid cooler as well. In other embodiments heat exchanger  575  is an engine oil cooler or other alternative purpose cooler. In other embodiments, the heat exchanger  575  can be integrated with the transmission or other device requiring use of coolant for cooling. 
     Thermal management system  605  as shown in  FIG. 6 , includes a microcontroller  670  configured to govern, control valve  620  according to powertrain operating conditions. Check valve  510  can be a ball check valve as previously discussed with respect to  FIG. 3 . Check valve  510  is a flap in another embodiment (e.g., as discussed with respect to  FIGS. 4 and 5 ). 
     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.