Abstract:
An improved transmission system is provided for an automotive vehicle having multiple engines for reason of fuel economy, including primary and secondary internal combustion engines separately supplied with fuel and having crankshafts in parallel orientation and terminating in co-directionally rotating flywheels. The improved transmission system includes a clutch mechanism associated with the flywheels for controllably transferring rotary force axially to input shafts in spaced apart parallel relationship and coupled by a power transfer mechanism. A sprag clutch is interactive between the secondary input shaft and the power transfer mechanism. A main gear, driven by the power transfer mechanism, is located within a gear box having speed change gears.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to the power train of an automotive vehicle for transmitting power from the engine to the driving wheels, particularly to that part of the power train known as the speed change transmission, and more particularly to speed change transmissions capable of receiving power from more than one power source. 
   2. Description of the Prior Art 
   The rising cost of automotive fuel has created a need for means for improving the fuel efficiency of automotive vehicles. Various solutions have been proposed. 
   One solution has been the hybrid automobile which uses an electric motor powered by batteries together with an internal combustion engine. It uses both the engine and the electric motor to provide sufficient combined power to accelerate and climb, etc., and then uses either the engine or the electric motor to travel economically at cruising speeds. The engine generally provides the power for recharging the batteries, so that in reality substantially all the power is provided by the automotive fuel. 
   Such hybrid systems are of high cost and complexity. The batteries can cost up to $5000.00 per vehicle, and have a limited service life of approximately 80,000 miles. The electric motor, electric generator and the necessary power transmission and control system as well as the means for integrating their function with that of the internal combustion engine result in additional high manufacturing and maintenance costs. 
   Another proposed approach for improving fuel economy is the use of two or more engines in one vehicle. All the engines are operated to produce enough power for acceleration, climbing, etc., and only one engine is used to maintain cruising speed for economical long distance travel. 
   U.S. Pat. No. 6,179,078 to Belloso discloses a fuel efficient and inexpensive automobile having two engines coupled to drive wheels by way of a continuously variable ratio torque converter. The vehicle uses both engines for quick acceleration, then uses either engine for economical cruising. A disadvantage of this system is the limited power capacity and limited speed range of current continuously variable ratio torque converters. 
   U.S. Pat. No. 6,637,283 to Belloso discloses a Control Apparatus for a Continuously Variable Transmission for extending the drive ratios and versatility of the CVT. It increases its operational speed range, provides reverse functionality and has the capacity to accommodate two different power sources. Its disadvantage is that most currently available continuously variable transmissions, particularly those using variable-pitch pulleys, have only limited power handling capacity, especially when compared to the standard manual and automatic transmissions that are in general use in automotive vehicles today. This control apparatus is not readily adaptable for use in these standard manual and automatic transmissions. 
   U.S. Pat. No. 4,439,989 to Yamakawa discloses a system with at least two engine units, a primary engine unit and an auxiliary engine unit, each coupled to a transmission through an electromagnetic power clutch. It is equipped with means for operating the two engines in a proper phase difference of, preferably, 180 degrees to prevent unwanted vibrations. A problem with this engine is the high complexity of the system used to make the engine units run at the specified proper phase difference between the engine units. Another disadvantage is that it does not readily lend itself to the use of dissimilar engine units, particularly units that differ in their optimal operating speeds. Furthermore this patent does not teach any improvement or modification of the standard manual or automatic transmissions to facilitate fuel savings. 
   Although improved fuel efficiency can be achieved through the use of a smaller fuel-efficient engine in an automobile, particularly for maintaining cruising speed, additional power is required for acceleration and hill climbing. Modified engine systems of the prior art have not proved truly satisfactory, either because of their excessive cost and complexity, or because of reliance upon continuously variable torque converters having inadequate power handling capacity. 
   There is, therefore, a need for an engine system which will not only permit selective use of power from a plurality of engines but will also make use of currently available standard manual or automatic transmissions, and take advantage of their proven versatility, reliability, durability and power-handling capacity. 
   It is accordingly a primary purpose of this invention to provide an automotive transmission equipped with multiple input ports for receiving power from a plurality of power sources and further equipped with means for selectively transmitting power from said sources to a common output shaft for eventual transmission to the driving wheels. 
   It is a particular object of this invention to provide an automatic transmission equipped with multiple input ports and adapted to receive power from multiple internal combustion engines. 
   It is also an object of this invention to provide a manual transmission equipped with multiple input ports for receiving power from multiple engines. 
   It is a further purpose of this invention to provide a transmission capable of receiving power from multiple power sources of dissimilar types, dissimilar operating speeds and dissimilar power output. 
   It is a further purpose of this invention to provide a fuel-efficient automotive vehicle equipped with two or more internal combustion engines, said vehicle being capable of selectively using the combined power of a plurality of said engines for acceleration, climbing, etc., and capable of selectively using power from a lesser number of said engines for economical travel. 
   It is yet another object of this invention to provide an automotive vehicle of the aforesaid nature that employs the currently generally used types of automatic or manual transmissions with a minimum of modifications of said transmissions. 
   It is a still further object of this invention to provide an automotive vehicle of the aforesaid nature wherein the additional power from the second (and third, etc.) engine/power source will be automatically engaged and disengaged, as needed, without requiring the operator to make substantial changes in the manner in which he regularly operates an automotive vehicle, hence without requiring him to have to upgrade his skill as an operator of motor vehicles. 
   These objects and other objects and advantages of the invention will be apparent from the following description. 
   SUMMARY OF THE INVENTION 
   The above and other beneficial objects and advantages are accomplished in accordance with the present invention by an improved manual or automatic speed change transmission capable of receiving power from multiple internal combustion engines, or other power sources, and transmitting their combined power to a common output shaft; said transmission being further capable of selectively disengaging any of said engines to maximize fuel economy, said improvements comprising:
     a) in a manually operated embodiment of said transmission, releasable coupling means such as a frictional clutch interactive with rotary power output means of each engine to transfer power axially to an associated transmission input shaft,   b) power transfer means for transferring power laterally between said input shafts, and comprised of an endless chain connected to sprockets, or spur gears, or combinations thereof,   c) an over-riding sprag clutch disposed between one or more of said input shafts and said power transfer means, and   d) a main shaft driven by said power transfer means and extending into a gear box having speed change gears, whereby   e) power from each power source is conveyed to each corresponding transmission input shaft through said releasable coupling, thence through said power transfer means through said sprag clutch to said main shaft, thence through conventional speed change gears.   

   In an automatically operated embodiment of the improved transmission of this invention, said releasable coupling means are fluid couplings such as a torque converter, and the speed change gears are those of a conventional automotive automatic transmission. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the figures of the drawing: 
       FIG. 1  is a top view partly in section, of a manually operated embodiment of the transmission of this invention shown in operative association with two internal combustion engines. 
       FIG. 2  is a sectional view taken in the direction of the arrows upon the line  2 - 2  of  FIG. 1  and further showing symbolic representation of a gas pedal and fuel supply lines. 
       FIG. 3  is a top view, partly in section, of an alternative manually operated embodiment of the transmission of this invention shown in operative association with two internal combustion engines. 
       FIG. 4  is a sectional view along line  4 - 4  of  FIG. 3 . 
       FIG. 5  is a sectional view along line  5 - 5  of  FIG. 3 . 
       FIG. 6  is a top view, partly in section, of an automatically operated embodiment of the transmission of this invention. 
       FIG. 7  is a sectional view taken along line  7 - 7  of  FIG. 6 . 
       FIG. 8  is a top view, partly in section, of an alternative embodiment of an automatic transmission shown in operative association with two internal combustion engines. 
       FIG. 9  is a sectional view along line  9 - 9  of  FIG. 8 . 
       FIG. 10  is a sectional view along line  10 - 10  of  FIG. 8 . 
   

   For clarity of illustration, details which are not relevant to the invention, such as shift levers, clutch pedals and linkages, multiple speed change gears inside the gearbox, planetary gears, brakes and clutches inside the automatic transmission housing have been omitted from these drawings. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1 and 2 , there is shown a primary engine  1  and a secondary engine  2  in operative association with manual transmission  3  embodying this invention. Primary engine  1  is fixedly bolted to left bell housing  4  of transmission  3 , while secondary engine  2  is fixedly bolted to right bell housing  5  of transmission  3 . Power from engine  1  is transmitted from its crankshaft  6  to its flywheel  7  positioned within bell housing  4 . Also located within bell housing  4  is primary clutch assembly  13  in axial alignment with flywheel  7 . Said clutch assembly is comprised of cover  12  attached to said flywheel, primary clutch plate  8  attached to primary input shaft  9  and pressure plate  11  adapted to interact with primary clutch plate  8 . Input shaft  9  extends through bell housing  4  to transmission main gear  10 . Accordingly, when pressure plate  11  interacts with clutch plate  8 , power is delivered from engine  1  to transmission main gear  10 . 
   Power from secondary engine  2  is transferred from its crankshaft  14  to its flywheel  15  positioned within bell housing  5 . Also located within bell housing  5  is secondary clutch assembly  20  in axial alignment with flywheel  15 . Said secondary clutch assembly is comprised of cover  19  attached to flywheel  15 , secondary clutch plate  16  attached to secondary input shaft  17 , and secondary pressure plate  18  adapted to interact with plate  16 . 
   Aside from having two clutch assemblies  13  and  20 , another fundamental novel feature of this invention is that left bell housing  4  and right bell housing  5  are fixedly integrated into one unit, either by being cast in one piece or by being fixedly bolted together. Furthermore, left bell housing  4  and right bell housing  5  include a common power transmission chamber  21  which is traversed by both the primary input shaft  9  and the secondary input shaft  17 , which are both journaled to the walls of chamber  21 . 
   A driven sprocket wheel  22  is fixedly mounted on primary input shaft  9  within chamber  21 . A drive sprocket wheel  23  is releasably mounted on secondary input shaft  17  through sprag clutch  24 . The inner race  25  of sprag clutch  24  is fixedly mounted on secondary input shaft  17  while the outer race  26  of said sprag clutch is fixedly mounted on drive sprocket wheel  23 . Driven sprocket wheel  22  is interactive with drive sprocket wheel  23  by way of a positive drive means embodied by gearing chain  27 , said assembly constituting a power transfer mechanism. 
   Sprag clutch  24  may be any suitable design of the various types of sprag clutches currently available. A sprag clutch consists of an inner race disposed within an outer race having a plurality of shaped parts known as “sprags” lodged in cam-shaped cavities in the annulus between the races. Sprag clutches automatically engage when the r.p.m. of the inner race is caused to equal or exceed the r.p.m. of the outer race. 
   Primary engine  1  and secondary engine  2  are disposed so that their crankshafts  6  and  14  turn in the same direction. Primary clutch assembly  13  and secondary clutch assembly  20  are actuated by one clutch pedal and are connected and adjusted in such a manner that they both release at essentially the same time when the clutch pedal is depressed and that they both engage at essentially the same time when the clutch pedal is released, even if the clutch pedal is released fairly gradually. 
   Fuel supply line  95  for primary engine  1  is connected to the gas pedal  96  in the conventional manner and is controlled by the operator in the conventional manner. Fuel supply line  97  to secondary engine  2  is connected via a controllably releasable linkage to the same gas pedal as well, so that when increased power is needed, such as when the vehicle is accelerating or climbing a grade, both engines may be operated to produce the required power by depressing the gas pedal. Means are provided, however, to selectively disconnect the fuel supply to secondary engine  2  when less power is needed, such as when cruising on a level highway. This means may be an electrically actuated device which may be manually switched on or off by the operator with a switch at a convenient location. 
   Alternatively, the means for connection or disconnection of the fuel supply for secondary engine  2  to the gas pedal may be controlled automatically in various ways. One way is for the said electrically actuated connecting device to remain connected when the transmission is on first, second or even third gear, and for said connecting device to be automatically disconnected when the transmission is on top gear or on overdrive. For further automatic versatility, means may be added to override the above-stated disconnection (when the transmission is in top gear or overdrive) when the gas pedal is depressed to a preset degree, signaling a call for increased power, such as for passing or climbing at high speed, to permit use of both engines simultaneously even when the transmission is set at top gear or overdrive. A further alternative may be to use “load sensors” or “torque sensors” to determine if additional power is needed from secondary engine  2 , and use signals from said sensors to override the above-stated disconnection of engine  2  from the gas pedal even when the transmission is on top gear or overdrive. 
     FIGS. 3 ,  4  and  5  illustrate an alternative embodiment of the above-described manual transmission. In this alternative embodiment, transmission main gear  28  is mounted on common transmission input shaft  29  rather than on primary input shaft  30 . Power from primary engine  31  is transmitted through primary clutch assembly  32  to primary input shaft  30  thence through primary sprag clutch  33  to primary drive sprocket  34  and primary gearing chain  35 , to primary driven sprocket  36  which is fixedly mounted on common transmission input shaft  29 . Sprag clutch  33  automatically engages when the rotational speed of primary input shaft  30  exceeds the rotational speed of primary drive sprocket  34 , such as when there is a load carried by common transmission shaft  29 . Sprag clutch  33  automatically disengages when the rotational speed of primary input shaft  30  falls below the rotational speed of primary drive sprocket  34 , such as when primary engine  31  is slowed down to idle speed. 
   Power from secondary engine  37  is transmitted through secondary clutch assembly  38  to secondary input shaft  39  thence through secondary sprag clutch  40  to secondary drive sprocket  41  and secondary gearing chain  42  to secondary driven sprocket  43  which is fixedly mounted on common transmission input shaft  29 . Primary engine  31  and secondary engine  37  are disposed so that their crankshafts  44  and  45  turn in the same direction. During high load situations when both primary engine  31  and secondary engine  37  are operated at full operational speeds, primary sprag clutch  33  and secondary sprag clutch  40  automatically engage as soon as clutch assemblies  32  and  38  are engaged, thereby delivering the combined power from engines  31  and  37  to common transmission input shaft  29 , thence through transmission main gear  28  to speed change transmission gears within gearbox  46 . 
   During light load situations either primary engine  31  or secondary engine  37  may be throttled down to idle speed, whereupon its corresponding associated sprag clutch  33  or  40  will automatically decouple it from the common transmission input shaft  29 . In this embodiment, therefore, the vehicle can travel economically at cruising speed on power from either primary engine  31  or secondary engine  37  by simply throttling down the other engine by means of controlled fuel supply. 
     FIGS. 6 and 7  illustrate an embodiment of the transmission of this invention which is automatically operated. Automatic transmission  47  has a primary bell housing  48  bolted to primary engine  49  and a secondary bell housing  50  bolted to secondary engine  51 . Primary bell housing  48  houses primary torque converter  52  which transmits power from primary engine crankshaft  53  through primary flywheel  54  and impeller  55  via a fluid coupling to turbine  56  joined to primary input shaft  57  which extends into a gear system within housing  58 . 
   Secondary bell housing  50  houses secondary torque converter  59  which transmits power from secondary engine crankshaft  60  through secondary engine flywheel  61  and impeller  62 , via a fluid coupling to turbine  63  joined to secondary input shaft  64 . Aside from having two torque converters  52  and  59 , this embodiment also has the novel feature of integrating primary bell housing  48  and secondary bell housing  50  into one unit, either by being cast in one piece or by being fixedly bolted together. Furthermore, bell housings  48  and  50  include a common power transmission chamber  65  which is traversed by both primary input shaft  57  and secondary input shaft  64  which are each journaled to the walls of chamber  65 . 
   Driven sprocket wheel  66  is fixedly mounted on primary input shaft  57 , while driver sprocket wheel  67  is releasably mounted on secondary input shaft  64  through sprag clutch  68  which has its inner race  69  fixedly connected to secondary input shaft  64 , and its outer race  70  fixedly attached to drive sprocket wheel  67 . Driven sprocket wheel  66  is interactive with drive sprocket wheel  67  by way of a positive drive means embodied by gearing chain  71 . Sprag clutch  68  automatically engages whenever secondary engine  51  is operated fast enough to contribute additional power to primary input shaft  57  such as during operations when increased power is required, and disengages automatically when secondary engine  51  is slowed down to idle speed to conserve fuel during operations when less power is needed. 
     FIGS. 8 ,  9  and  10  illustrate an alternative embodiment of an automatic transmission embodying the invention. This embodiment features a common transmission input shaft  72  journaled to the walls of power transmission chamber  73 . Power from primary engine  74  is transmitted through primary fluid torque converter  75  to primary input shaft  76  thence through primary sprag clutch  77  to primary drive sprocket  78  and primary gearing chain  79  thence to primary driven sprocket  84  which is fixedly mounted on common input shaft  72 . Similarly, power from secondary engine  80  is transmitted through secondary fluid torque converter  81  to secondary input shaft  82  thence through secondary sprag clutch  83  to secondary drive sprocket  85  and secondary gearing chain  86 , thence to secondary driven sprocket  87  fixedly mounted on common input shaft  72 . Said shaft  72  extends into the main automatic transmission housing  88  as the main transmission shaft  89  which drives a speed change planetary gear system housed within housing  88 . 
   Engines  74  and  80  are disposed so that their crankshafts,  90  and  91 , respectively, rotate in the same direction while in operation. When increased power is needed both engines  74  and  80  are operated at high enough speeds to supply the required power. Power from each said engine is transmitted by torque converters  75  and  81  to input shafts  76  and  82 , thence through sprag clutches  77  and  83 , drive sprockets  78  and  85 , gearing chains  79  and  86  and driven sprockets  84  and  87  to common input shaft  72 , thence to a planetary gear system within housing  88 . When less is needed, either engine may be throttled down to idle speed to conserve fuel, causing the selected engine to be automatically de-coupled from the transmission by its associated sprag clutch. The advantage of this alternative embodiment is that it gives the operator a choice as to which engine to use for traveling economically at cruising speeds. 
   The system for controlling the fuel supply to the engines automatically, as described hereinabove with respect to manual transmissions can also be applied to the embodiment involving an automatic transmission. For example, the fuel supply to both engines may be controlled through one gas pedal calibrated to operate both engines at equal speeds when the automatic transmission is in the lower gears, and further provided with means for automatically switching either engine to “idle” speed whenever the transmission shifts to high gear. Furthermore, means may be provided for automatically switching the “idling” engine back to operational speed through the use of suitable “load sensors” or “torque sensors” when it is sensed that more power is needed, or simply whenever the operator asks for more power by depressing the gas pedal. These control mechanisms make this vehicle essentially as simple to operate as any regular vehicle equipped with a single engine. 
   While particular examples of the present invention have been shown and described, it is apparent that changes and modifications may be made therein without departing from the invention in its broadest aspects. The aim of the appended claims, therefore, is to cover all such changes and modifications as fall within the true spirit and scope of the invention.