Abstract:
The present invention provides a hybrid conversion module configured to easily attach to existing powertrain components in order to produce a light hybrid vehicle. The hybrid conversion module includes an electric motor/generator operable to transmit power to a torque converter and thereby drive the light hybrid vehicle. A storage device such as a battery is operatively connected to the electric motor/generator and is configured to transmit energy to or receive energy from the electric motor/generator. A clutch is configured to selectively decouple the light hybrid vehicle&#39;s engine from the torque converter such that the vehicle can be powered by the electric motor/generator in an efficient manner. The apparatus of the present invention also includes a light hybrid vehicle having such a hybrid conversion module attached in the manner described to a conventional powertrain.

Description:
TECHNICAL FIELD 
       [0001]    The present invention pertains generally to a light hybrid vehicle configuration with a selectively applied input disconnect clutch. 
       BACKGROUND OF THE INVENTION 
       [0002]    The purpose of a vehicular transmission is to provide a neutral, at least one reverse and one or more forward driving ranges that impart power from an engine, and/or other power sources, to the drive members which deliver the tractive effort from the vehicle to the terrain over which the vehicle is being driven. As such, the drive members may be front wheels, rear wheels or a track, as required to provide the desired performance. 
         [0003]    It is well known that hybrid vehicles and light hybrid vehicles can offer numerous advantages including, for example, improved fuel economy and reduced emissions. Light hybrid vehicles employ a single motor/generator along with an engine which may individually or in combination drive a transmission in order to power the vehicle. 
       SUMMARY OF THE INVENTION 
       [0004]    The apparatus of the present invention includes a hybrid conversion module configured to easily attach to existing powertrain components and thereby provide a light hybrid vehicle. The hybrid conversion module includes an electric motor/generator operable to transmit power to a torque converter and thereby drive the light hybrid vehicle. A storage device such as a battery is operatively connected to the electric motor/generator and is configured to transmit energy to or receive energy from the electric motor/generator. A clutch is configured to selectively decouple the light hybrid vehicle&#39;s engine from the torque converter such that the vehicle can be powered by the electric motor/generator in an efficient manner. The apparatus of the present invention also includes a light hybrid vehicle having such a hybrid conversion module attached in the manner described to a conventional powertrain. 
         [0005]    The electric motor/generator may be attached directly to the torque converter such that the torque converter can be implemented to cool the electric motor/generator by transmitting engine heat through the torque converter housing where it is absorbed by working fluid within the torque converter. 
         [0006]    The electric motor/generator may be configured to drive a transmission pump such that coolant flow and clutch pressure are maintained when the light hybrid vehicle is electrically driven. 
         [0007]    The clutch may be an electro-magnetic clutch. 
         [0008]    The storage device may be a battery. 
         [0009]    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. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1   a  is a schematic illustration of a prior art non-hybrid vehicle; 
           [0011]      FIG. 1   b  is a schematic illustration of a light hybrid vehicle in accordance with the present invention; 
           [0012]      FIG. 2  is a detailed sectional view of a hybrid conversion module of  FIG. 1   b ; and 
           [0013]      FIG. 3  is a detailed sectional view of an alternate embodiment of the hybrid conversion module of  FIG. 1   b.    
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    Referring to the drawings,  FIG. 1   a  shows a schematic representation of a conventional vehicle  10 . The vehicle  10  includes an engine  12 , a torque converter  14 , a transmission  16  and one or more drive members  18 . 
         [0015]    The torque converter  14  includes a turbine  20  (a driven member), an impeller  22  (a driving member), and a stator  24 . The torque converter  10  further includes a torque converter housing  26  (shown in  FIG. 2 ) attached to the impeller  22  such that a chamber full of working fluid (not shown) is formed therebetween. As will be described in detail hereinafter, the impeller  22  is operatively connected to and driven by the engine  12 , and engine torque is transmitted from the impeller  22  to the turbine  20  through an operation of the working fluid. The turbine  20  is operatively connected to the transmission  16  such that torque is transferable therebetween to drive the vehicle  10 . 
         [0016]    When the engine  12  is running, the rotating impeller  22  causes working fluid (not shown) to be directed outward toward the turbine vanes (not shown). When this occurs with sufficient force to overcome the resistance to rotation, the turbine  20  begins to turn which correspondingly turns the transmission input shaft  25  (shown in  FIG. 2 ). The fluid flow exiting the turbine  20  is directed back into the impeller  22  by way of the stator  24 . The stator  24  redirects the fluid flow from the turbine  20  to the impeller  22  in the same direction as impeller rotation, thereby reducing impeller torque and causing torque multiplication. 
         [0017]    The transmission  16  transfers power from the engine  12  via the torque converter  14  to the drive members  18 . The drive members  18  deliver the tractive effort from the vehicle  10  to the terrain over which the vehicle  10  is being driven. As such, the drive members  18  may be front wheels, rear wheels or a track, as required to provide the desired performance. 
         [0018]    Referring to  FIG. 1   b , a schematic representation of a light hybrid vehicle  30  in accordance with the present invention is shown. For purposes of the present invention, a “light hybrid vehicle” is a hybrid vehicle that employs a single motor/generator along with an engine which may individually or in combination power the vehicle. Like reference numbers are used in  FIG. 1   b  to refer to like components from  FIG. 1   a.    
         [0019]    The light hybrid vehicle  30  includes an engine  12 , a torque converter  14 , a transmission  16  and one or more drive members  18  which are similar to the components previously described with respect to  FIG. 1   a . The light hybrid vehicle  30  also includes a hybrid conversion module  32  disposed between the engine  12  and the torque converter  14 . As will be described in detail hereinafter, the hybrid conversion module  32  is configured to easily attach to a non-hybrid vehicle such as the vehicle  10  (shown in  FIG. 1   a ) and convert it to a light hybrid vehicle such as the light hybrid vehicle  30 . 
         [0020]    The hybrid conversion module  32  includes an electro-magnetic clutch  34 , an electric motor/generator  36  and a battery  38 . The electro-magnetic clutch  34  is adapted to selectively couple or decouple the engine  12  and the torque converter  14 . When the electro-magnetic clutch  34  is deactivated, the engine  12  and the torque converter  14  are coupled such that the engine  12  may be implemented to power the vehicle  30  in a conventional manner. When the electro-magnetic clutch  34  is activated, the engine  12  and the torque converter  14  are decoupled such that the electric motor/generator  36  may be implemented to power the vehicle  30  without back-driving the engine  12 . In other words, activating the electro-magnetic clutch  34  improves vehicle efficiency when the vehicle  30  is being powered by the electric motor/generator  36 . 
         [0021]    The electric motor/generator  36  can draw energy from the battery  38  in order to power the vehicle  30  by itself or in combination with the engine  12 . More precisely, the electric motor/generator  36  can transmit power through the torque converter  14 , the transmission  16  and to the drive members  18  to power the vehicle  30 . As will be described in detail hereinafter, when the vehicle  30  is being powered by the engine  12 , rotation of the torque converter  14  may be converted to energy by the electric motor/generator  36  and stored in the battery  38 . Additionally, when the vehicle  30  is decelerating, rotation from the drive members  18  is transferable through the transmission  16  to back-drive the torque converter  14 . The rotation of the back-driven torque converter  14  may also be converted to energy by the electric motor/generator  36  and stored in the battery  38 . 
         [0022]    Referring to  FIG. 2 , the hybrid conversion module  32  is shown in more detail. Like reference numbers are used in  FIG. 2  to refer to like components from  FIGS. 1   a - 1   b.    
         [0023]    The engine  12  (shown in  FIG. 1   b ) drives a flywheel  50 . A friction plate  52  is biased into engagement with the flywheel  50  by a spring  54  such that the flywheel  50  and the friction plate  52  rotate together until the spring  54  is released. The spring  54  is preferably a Belleville type spring; however alternate spring configurations may be envisioned. The bias of the spring  54  provides a steady state condition wherein the engine  12  and the torque converter  14  are coupled and power is transferable therebetween to drive the vehicle  30 . 
         [0024]    The electro-magnetic clutch  34  is controllable to selectively release the spring  54  such that the flywheel  50  and the friction plate  52  rotate independently, and the engine  12  (shown in  FIG. 1   b ) is thereby decoupled from the torque converter  14 . The electro-magnetic clutch  34  includes a first clutch member  56 , a second clutch member  58 , and an electrically actuatable magnetic device  60  such as a magnetic coil. The first clutch member  56  is rigidly secured to a housing  62 . The magnetic device  60  is retained by the first clutch member  56  and is positioned in close proximity to the second clutch member  58 . 
         [0025]    As will be described in detail hereinafter, the second clutch member  58  is translatable in an axial direction relative to the first clutch member  56 . The second clutch member  58  is operatively connected to an annular link  64  such that the two components can rotate independently but translate in an axial direction together. To facilitate independent rotation, a bearing device  66  is preferably disposed between the second clutch member  58  and the annular link  64 . The annular link  64  also retains a radially inner portion  68  of the spring  54 . 
         [0026]    As previously indicated, the friction plate  52  is biased into engagement with the flywheel  50  by the spring  54  such that engine  12  (shown in  FIG. 1 ) and the torque converter  14  are coupled in the absence of an externally applied force. This spring bias also pulls the second clutch member  58  away from the first clutch member  56 . The electro-magnetic clutch  34  is actuatable to overcome the bias of the spring  54  and thereby decouple the engine  12  from the torque converter  14 . More precisely, by energizing the magnetic device  60  of the electro-magnetic clutch  34 , the second clutch member  58  is magnetically drawn or pulled toward the first clutch member  56 . The translation of the second clutch member  58  pulls the annular link  64  and the radially inner portion  68  of the spring  54  mounted thereto such that the spring  54  is released and the friction plate  52  disengages the flywheel  50 . 
         [0027]    The friction plate  52  preferably includes one or more damper springs  70  configured to at least partially absorb any engine torque spikes. The friction plate  52  is splined to a shaft member  72  such that the two components rotate together. The shaft member  72  is preferably attached to the torque converter housing  26  such as with the weld  74 . The torque converter housing  26  is attached to the impeller  22 . Therefore, when the engine  12  (shown in  FIG. 1   b ) and the torque converter  14  are coupled, engine rotation is imparted via the flywheel  50  to the friction plate  52 , to the shaft member  72 , to the torque converter housing  26 , and to the impeller  22  thereby causing the impeller  22  to rotate. Impeller rotation  22  spins the turbine  20  in the manner described hereinabove. The turbine  20  is attached, such as with a rivet  76 , to a coupling member  78 . The coupling member  78  is splined to the transmission input shaft  25  such that turbine rotation drives the transmission input shaft  25  and thereby powers the vehicle  30 . 
         [0028]    The electric motor/generator  36  includes a stator  80  and a rotor  82 . The stator  80  is mounted to an internal surface of the housing  62  and remains stationary relative to the rotor  82 . The rotor  82  is mounted to an external surface of the torque converter housing  26  and rotates relative to the stator  80  along with the torque converter housing  26 . Therefore, the electric motor/generator  36  can draw electricity from the battery  38  (shown in  FIG. 1   b ) in order to rotate the torque converter housing  26  and thereby power the vehicle  30 . Alternatively, rotation of the torque converter housing  26  generated by the engine  12  or during vehicle deceleration may be converted to electricity by the electric motor/generator  36  and stored in the battery  38 . 
         [0029]    The hybrid conversion module  32  is configured to easily attach to a non-hybrid vehicle such as the vehicle  10  (shown in  FIG. 1   a ) and convert it to a light hybrid vehicle such as the light hybrid vehicle  30 . The electric motor/generator  36  is preferably directly attached to the torque converter housing  26  in a conventional manner such as, for example, with the weld  84 . The electro-mechanical clutch  34  may be disposed in a preexisting area between the flywheel  50  and the torque converter housing  26 , and may be secured to the housing  62  with a threaded fastener  86 . 
         [0030]    By mounting the electric motor/generator  36  directly to the torque converter housing  26 , fluid flow within the torque converter  14  may be implemented to cool the rotor  82 . More precisely, the heat generated by the rotor  82  is transmitted through the torque converter housing  26  where it is exposed to and absorbed by the working fluid (not shown) within the torque converter  14 . As the working fluid exits the torque converter, it is directed outward and thru the support housing of stator  80  via a coolant channel (not shown) which is similar to the coolant channel  100  shown in  FIG. 3 . This transfer of fluid maintains a common temperature of the rotor  82  and the stator  80 , and thereby provides consistency in clearances of the rotor and stator air gap necessary to provide excellent performance. The fluid is then preferably sent to a transmission oil cooler (not shown) and returned to the transmission lubrication system (not shown). 
         [0031]    Locking the rotor  82  to the torque converter  14  allows “hill holding” by controlling the speed of the electric motor/generator  36 . For purposes of the present invention, “hill holding” refers to the ability of the vehicle  30  to maintain position on an incline or decline without moving. During motion, at powers up to the limit of the electric device, maintaining speed control in the torque converter, ensures, transparent connect or disconnect of the engine. The electric motor/generator  36  maintains the same input to the torque converter  14 , which will ensure the same output torque and speed of this device, and therefore, the same vehicle propulsion characteristics. This simplifies control algorithms by simple speed match algorithms which may be stored in an electronic control unit (not shown). 
         [0032]    The hybrid conversion module  32  may be implemented to electrically launch the vehicle  30  and thereby improve fuel consumption. During such operation, the rotor  82  preferably drives the main transmission pump  88  to maintain coolant flow and clutch pressure. The engine  12  is thereafter preferably started by balancing the power transfer to the clutch  34  and the engine  12  while the vehicle  30  is driving. 
         [0033]    Referring to  FIG. 3 , an alternate embodiment of a hybrid conversion module  32  is shown. Like reference numbers are used in  FIG. 3  to refer to like components from  FIG. 2 . Additionally, the suffix “a” added to a reference numeral identifies a similar component in a different embodiment. 
         [0034]    The electro-magnetic clutch  34   a  functions similarly to the electro-magnetic clutch  34  (shown in  FIG. 2 ) described hereinabove, and will therefore not be described further. The stator  80   a  is mounted to an internal surface of the housing  62   a  and remains stationary relative to the rotor  82   a . The rotor  82   a  is mounted to a transfer member  90 . The transfer member  90  is preferably generally annular and includes a radially outer portion  92  to which the rotor  82   a  is mounted, and a radially inner portion  94  integrally extending from a shaft member  96 . Although the transfer member  90  is preferably an integral extension of the shaft member  96 , the two components may alternately be attached together in any conventional manner. The transfer member  90  is attached to the torque converter housing  26   a  such that the rotor  82   a , the transfer member  90 , the torque converter housing  26   a , and the shaft member  96  all rotate together. 
         [0035]    The friction plate  52   a  is splined to the shaft member  96  such that the two components rotate together. Therefore, when the engine  12  (shown in  FIG. 2 ) and the torque converter  14   a  are coupled, engine rotation is imparted via the flywheel  50   a  to the friction plate  52   a , to the shaft member  96 , to the transfer member  90 , and then to both the rotor  82   a  and the torque converter housing  26   a . Rotation of the torque converter housing  26   a  causes the impeller  22   a  to rotate. Impeller rotation spins the turbine  20   a  in the manner described hereinabove with respect to the turbine  20  (shown in  FIGS. 1   b  and  2 ), and a stator  24   a  is operational to multiply torque in the manner previously described with respect to the stator  24  (shown in  FIG. 2 ). The turbine  20   a  is attached, such as with a rivet  76   a , to a coupling member  78   a . The coupling member  78   a  is splined to a transmission input shaft  25   a  such that turbine rotation drives the transmission input shaft  25   a  and thereby powers the vehicle  30   a.    
         [0036]    The electric motor/generator  36   a  can draw electricity from the battery  38  (shown in  FIG. 1   b ) in order to rotate the torque converter housing  26   a  and thereby power the vehicle  30   a . Alternatively, rotation of the transfer member  90  either by the engine  12  (shown in  FIG. 1   b ) or during vehicle deceleration may be converted to electricity by the electric motor/generator  36   a  and stored in the battery  38 . 
         [0037]    Fluid from the torque converter  14   a  may be implemented to cool the electric motor/generator  36   a . More precisely, fluid exiting the torque converter is directed outward and then thru the support housing of stator  80   a  via a coolant channel  100  in order to absorb motor heat and thereby cool the electric motor/generator  36   a . The fluid is then preferably sent to a transmission oil cooler (not shown) and returned to the transmission lubrication system (not shown). 
         [0038]    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.