Patent Publication Number: US-2006000650-A1

Title: Hybrid vehicle conversion kit

Description:
BACKGROUND OF THE INVENTION  
      This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/582,101 filed Jun. 23, 2004, the complete disclosure of which is hereby expressly incorporated by reference.  
      This invention relates to a hybrid electrical drive system for a vehicle, and in particular, to a conversion kit for converting a vehicle with a standard internal combustion engine into a hybrid electrical vehicle. The conversion kit is designed to increase the fuel efficiency and travel range of the vehicle so converted, and to provide additional horse power upon acceleration. The system utilizes a novel arrangement to intercept kinetic energy that would normally be wasted as the vehicle is decelerating or braking. The system converts the kinetic energy to electrical energy to recharge an on board electrical energy supply source for use in assisting with the acceleration of the vehicle.  
      In an effort to conserve resources and reduce environmental impact, a growing effort has been made to produce electrical vehicles or hybrid electrical vehicles, which use a combination of electric power and an alternate power source, such as an internal combustion engine. A challenge has always been how to provide increased range and power of a hybrid vehicle to reduce the frequency of stops required for refueling the internal combustion engine or to recharge the energy storage system from an external energy source.  
      It is well known to provide both AC and DC drive motors on an electrical vehicle. Furthermore, one method that is well known for trying to increase the range of an electrical vehicle or a hybrid electrical/internal combustion vehicle is to provide a regenerative braking system. A regenerative braking system captures a portion of the kinetic energy in a vehicle during deceleration. As the vehicle is decelerating, the electric motor of an electric vehicle may be used to provide a kinetic braking force and is operated as a generator used to generate electrical energy to recharge the energy storage system. Of course, a separate motor/generator may also be used to provide the braking force as is common in a hybrid vehicle. The electrical energy produced by the regenerative system is stored in an energy storage system and is used to power the vehicle&#39;s electric motor to increase the range of the vehicle. Examples of regenerative braking systems are found in U.S. Pat. No. 6,033,041 to Koga, et al.; U.S. Pat. No. 6,222,334 to Tamagawa, et al.; U.S. Pat. No. 6,490,511 to Raftari, et al.; U.S. Pat. No. 6,497,635 to Suzuki; and U.S. Pat. No. 6,518,732 to Palanisami, all of which are fully incorporated herein by reference.  
      Although the rate of sales has been increasing greatly in recent years for hybrid vehicles, hybrid vehicles still only account for a mere fraction of new vehicle sales. One reason for this is that there is a significant premium on the price for hybrid vehicles that tends to far exceed the fuel cost and any tax savings that may be achieved with the hybrid vehicle. Furthermore, there is not currently any aftermarket conversion available for converting a standard internal combustion engine into a hybrid vehicle.  
      It is, therefore, an object of the invention to provide a kit for use in converting a standard internal combustion engine into a hybrid vehicle that includes a regenerative braking and electrical power assist motor/generator to increase the fuel efficiency of internal combustion vehicles. It is a further object of the invention to provide the conversion kit in an economical manner that will allow the owner to realize a savings in the operation of the vehicle.  
     SUMMARY OF THE INVENTION  
      It is a feature of the invention to provide a conversion kit for use in converting a vehicle having a standard internal combustion engine into a hybrid electrical vehicle. In one embodiment, the invention includes a DC electric motor/generator, a controller, and an electrical energy supply source. During deceleration periods, the electric motor/generator recharges the electrical energy supply source, which may be a battery or a battery array, and during period of acceleration, the controller controls the battery array to provide electrical energy to drive the electric motor and assist the internal combustion engine in accelerating the vehicle. In one embodiment, the electric motor/generator assembly is mounted on an output shaft attached to the transmission of the vehicle.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above-mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the present invention taken in conjunction with the accompanying drawings, wherein:  
       FIG. 1  is a schematic diagram of a vehicle retrofitted with a hybrid conversion kit of the present invention;  
       FIG. 2  is a perspective view of a typical transmission output shaft and housing with a portion of the housing cut away;  
       FIG. 3  is a perspective view of a DC electric motor/generator and housing of the hybrid conversion kit shown with a portion of the housing cut away and installed on a transmission output shaft;  
       FIG. 4  is a side view of a typical prior art drive assembly including a transmission, an output shaft, an output extension housing and a drive shaft for a rear wheel drive vehicle;  
       FIG. 5  is a side view of the drive assembly of  FIG. 4  with the output, extension housing, and drive shaft removed from the transmission output shaft;  
       FIG. 6  is a side view of the drive assembly of  FIG. 4  with the DC electric motor/generator of the hybrid conversion kit being installed to replace the standard output extension housing with a portion of the housing of the DC electric motor/generator cut away; and  
       FIG. 7  is a side view of the drive assembly shown in  FIG. 6  with the DC motor/generator and drive shaft installed on the transmission to convert the vehicle into a hybrid. 
    
    
      Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplification set out herein illustrates an embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.  
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION  
      For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates.  
      Referring now to  FIG. 1 , a hybrid conversion kit generally indicated as  10  is shown installed on a vehicle generally indicated as  12 . In the embodiment shown, vehicle  12  is a rear-wheel drive vehicle and includes a drive assembly  13 ; an internal combustion engine  14 , such as a gasoline or diesel engine as is well known; a transmission, which may be of a known manual or automatic version; and a drive shaft  18  driven by the transmission  16 . Vehicle  12  also includes a differential  20  connected to the transmission, a rear axle  22  extending outwardly from the differential and generally perpendicular to the drive shaft, and a pair of rear wheels/tires  24   a ,  24   b . Drive assembly  13  also includes a pair of conventional rear brakes  26   a ,  26   b  mounted to rear wheels  24   a ,  24   b , respectively. It should be noted that besides the components included in hybrid conversion kit  10 , vehicle  12  and drive assembly  13  are typical for a standard internal combustion rear-wheel drive vehicle.  
      Referring now to  FIG. 2 , before being converted to a hybrid system, drive assembly  13  would include a transmission output shaft  27  and an output extension housing  28 . The extension housing  28  is replaced when hybrid conversion kit  10  is installed on the vehicle as discussed in further detail below. Transmission output shaft  27  includes a splined end  29  for mounting drive shaft  18  to transmission output shaft  27 . Splined end  29  is located at the end of output shaft  27  opposite the end that is attached to transmission  16 . Output extension housing  28  includes a mounting flange  30  having mounting holes  32  for mounting the output extension housing  28  to transmission  16  with bolts or other fasteners (not shown). Also included in a typical drive assembly  13  are a universal joint  34  and a yolk  36  on the end of drive shaft  18  as shown in  FIGS. 4-7 .  
      Referring again to  FIG. 1 , hybrid conversion kit  10  includes a DC electric motor/generator assembly  40 , a controller  42 , and an electrical energy supply source  44 . Motor/generator assembly  40  is mounted to the transmission on transmission output shaft  27  as shown in  FIG. 3 . Motor/generator assembly  40  includes a housing  50 , an armature  52 , and a connecting armature shaft  54  having a splined end  56  and a sleeve  57  having internal splines for making a driving connection with splined end  29  of transmission output shaft  27 . Motor/generator assembly  40  also includes electrical wires  58  and a connector  59  for electrically connecting motor/generator assembly  40  to controller  42  and electrical energy supply source  44 . Housing  50  includes an opening  60  at one end for allowing splined end  56  of connecting shaft  54  to be connected to drive shaft  18  and a flange  62  having mounting holes  64  so that motor/generator assembly  40  can be bolted to the same holes in transmission  16  to which output extension housing  28  is mounted prior to installing hybrid conversion kit  10 . Housing  50  also includes an opening  66  adjacent flange  62  for receiving transmission output shaft  27 . A number of high quality electric motors are presently available for use with existing hybrid vehicles and can readily be modified with the features of the motor/generator assembly  40 . For example, Wavecrest offers a motor that may be very suitable for motor/generator assembly  40 .  
      Controller  42  utilizes conventional components and circuitry as are known in the art. Through a wiring harness, the controller  42  may monitor signals such as the throttle position sensor, brake sensor and reverse gear light switch (not shown). Controller  42  preferably also monitors the battery&#39;s state of charge to adjust regenerative braking draw from the electrical motor/generator during deceleration. Controller  42  may also be connected to the alternator (not shown) of vehicle  12  to accept any additional charging current required and may use the alternator&#39;s current presence to monitor key-on and key-off status. Electrical energy supply source  44  may be a battery or battery array such as lithium ion polymer, nickel-chromium, lead acid or other suitable type. It is believed that lithium batteries may offer an advantage in that they tend to be more energy dense, lighter and operate at lower temperatures and typically do not produce fumes or gases. The batteries may be mounted anywhere on the vehicle where space permits as further described below.  
      Prior to installing hybrid conversion kit  10 , a portion of drive assembly  13  of vehicle  12  will appear as shown in  FIG. 4 . In this view, transmission output shaft  27  is shown mounted to and extends from transmission  16  and is covered by output extension housing  28 , which is bolted to transmission  16 . Yoke  36  of drive shaft  18  is fitted on splined end  29  of the transmission output shaft for providing driving rotation of the driving shaft to drive the rear wheels. To install hybrid conversion kit  10 , drive shaft  18  is removed from transmission output shaft  27 , and output extension housing  28  is removed from transmission  16  as shown in  FIG. 5 .  
      Now referring to  FIG. 6 , to install hybrid conversion kit  10 , DC motor/generator assembly  40  is placed ready for installation on transmission output shaft  27 . DC motor/generator assembly  40  is then installed by inserting transmission output shaft  27  through opening  66  of housing  50  into sleeve  57  of connecting armature shaft  54  until motor/generator assembly abuts against transmission  16 . In this manner, splined end  29  of transmission output shaft  27  will be drivingly engaged with the internal splines of sleeve  57  of connecting armature shaft  54 . Housing  50  of motor/generator assembly  40  may be bolted to transmission  16  using mounting holes  64  and flange  62 . Also, yoke  36  of drive shaft  18  is placed through opening  60  in housing  50  and around splined end  56  of connecting armature shaft  54 . Yoke  36  is provided with internal splines to mate with the splines on end  56  for driving engagement of drive shaft  18 .  
      The batteries or other energy storage device of electrical energy supply source  44  may be mounted in any convenient place in vehicle  12 . For example, batteries may be installed in the C-channel frame of a truck, or the batteries for hybrid conversion kit  10  may also be used to replace the vehicle&#39;s main battery with a dual voltage battery. Controller  42  may also be mounted in any convenient and environmentally appropriate place in vehicle  12 . Connector  59  is connected to controller  42  and electrical connecting wires (not shown) are also provided between controller  42  and battery/electrical energy supply source  44 . As discussed above, electrical leads (not shown) may also be connected to the vehicle&#39;s alternator output, the throttle position sensor, the brake switch or a pressure transducer for proportional magnetic braking, and the reverse indicator circuit, (all of which are known and not shown).  
      When vehicle  12  is operating with hybrid conversion kit  10 , during initial acceleration, controller  42  receives a signal from the throttle position sensor indicating input from the driver. Controller  42  proportionally delivers electrical current to electric motor/generator assembly  42  from electrical energy supply source  44  in accordance with the demand from the accelerator. This provides rotational torque that is applied to drive shaft  18 , in addition to the torque supplied from engine  14 , for propelling vehicle  12 .  
      Once vehicle  12  has achieved an application specific preset speed, controller  42  suspends providing current to motor/generator assembly  40 , which will free wheel at higher speeds. During deceleration of vehicle  12  as recognized through the throttle position sensor signal or brake application, controller  42  begins proportionally drawing current from electric motor/generator  40  as the armature is engaged and spun by transmission output shaft to charge electrical energy supply source/batteries  44 . Additionally, the armature provides a magnetic braking effect while the motor/generator assembly  40  is generating current and aids in braking vehicle  12 , which adds to the surface life of friction brakes  26   a ,  26   b.    
      When vehicle  12  decelerates from higher speeds, the regenerative braking effect may be significantly more energy efficient than standard battery operated electric vehicles. Furthermore, electrical energy supply source  44  may also be charged by the vehicle&#39;s alternator. Conversely, the regenerative braking electrical energy may assist vehicle  12 &#39;s engine driven alternator to charge the vehicle&#39;s regular battery.  
      This operational process repeats itself during every acceleration and deceleration cycle. Accordingly, it is believed that the benefits of a converted hybrid gas/electrical vehicle, may be operated at a fraction of the cost, while delivering benefits to the end user in a standard vehicle as a bolt on after market kit.  
      It should be appreciated that hybrid conversion kit  10  may be used with a multiplicity of vehicles. Rear-wheel drive trucks, vans, recreational vehicles, delivery trucks, postal trucks, route and surface vehicles have a drive assembly that lends itself for easily incorporating the hybrid conversion kit to take advantage of the benefits of the invention. In addition, front wheel drive and four wheel drive vehicles, including cars, SUVs and trucks, can be converted by placing an electric motor between the transmission output and the vehicle&#39;s wheels. For these types of vehicles, the mounting of an electric motor case/shaft design are modified for their particular components of the drive system. In addition, larger vehicles with two piece drive shafts can incorporate an electric motor/generator behind the transmission and between the transmission output shaft and the drive shaft support bearing. It is believed that only about 15-20 mounting variations are required to cover over 80% of the current light truck market.  
      While the invention has been taught with specific reference to the above described embodiments, one skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. As such, the described embodiments are to considered in all respects only as illustrative and not restrictive. Accordingly, the scope of the invention is not limited by the above description or drawings.