Abstract:
A torsional compensating device for an internal combustion engine for an internal combustion engine is provided. The torsional compensating device comprises a first joint assembly and a torsional element. The first joint assembly is in driving engagement with an output of the internal combustion engine. The torsional element is in driving engagement with the first joint assembly and the output of the internal combustion engine. An angular deviation of the first joint assembly causes a cyclical acceleration of the torsional element. The cyclical acceleration of the torsional element applies a torque to the output of the internal combustion engine. The torsional compensating device may be passively or dynamically adapted for both an amplitude and a phase of a torque ripple while minimizing an interference with an operation of the internal combustion engine.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application No. 61/778,745 filed on Mar. 13, 2013, which is incorporated herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to internal combustion engines and more specifically to a torsion based torque ripple compensating device for use with an internal combustion engine. 
       BACKGROUND OF THE INVENTION 
       [0003]    Due to recent improvements in combustion engine technology, there has been a trend to downsize internal combustion engines used in vehicles. Such improvements also result in more efficient vehicle, while maintaining similar performance characteristics and vehicle form factors favoured by consumers 
         [0004]    One common improvement used with internal combustion engines is the addition of a supercharger or a turbocharger. Typically, the addition of the supercharger or the turbocharger is used to increase a performance of an engine that has been decreased in displacement or a number of engine cylinders. Such improvements typically result in an increased torque potential of the engine, enabling the use of longer gear ratios in a transmission of the vehicle. The longer gear ratios in the transmission enable engine down-speeding. Engine down-speeding is a practice of operating the engine at lower operating speeds. Such improvement s typically result in improved fuel economy, operation near their most efficient level for a greater amount of time compared to conventional engines, and reduced engine emissions. 
         [0005]    In some designs, however, engine down-speeding can result in an undesirable increase in torque ripple at low operating speeds of the engine. For example, a significantly increased torque ripple can appear at an engine output when the engine is operating at low idle speeds. The torque ripple is a well-known engine dynamic that results from torque not being delivered constantly, but periodically during each power stroke of the operating cycle of an internal combustion engine.  FIG. 1  is a graph illustrating a torque output of an engine during a four stroke cycle of an engine. In the four stroke cycle, the torque ripple happens once every two turns of a crankshaft for each cylinder of the engine. Accordingly, a four cylinder engine will have two torque ripples per crankshaft turn while a three cylinder engine will have three ripples every two crankshaft turns. 
         [0006]    An amplitude of the torque ripple also varies with an operating speed of the engine and a load applied to the engine. A phase of the torque ripple varies with a rotation of the engine. Torque ripples can cause many problems for components of the vehicle near the engine, such as but not limited to: increased stress on the components, increased wear on the components, and exposure of the components to severe vibrations. These problems can damage a powertrain of the vehicle and result in poor drivability of the vehicle. In order to reduce the effects of these problems, smooth an operation of the engine, and improve an overall performance of the engine, the torque ripples may be compensated for using an engine balancing method. Many known solutions are available for multi-cylinder engine configurations to reduce or eliminate the stresses and vibration caused by the torque ripples. 
         [0007]    Torque ripple compensator devices are known in the art; however, the known device have many shortcomings. In many conventional vehicles, the torque ripples are compensated for using at least one flywheel.  FIG. 2  illustrates a conventional flywheel based damping system. In other applications, a dual-mass flywheel system may be used. An inertia of the flywheel dampens a rotational movement of the crankshaft, which facilitates operation of the engine running at a substantially constant speed. Flywheels may also be used in combination with other dampers and absorbers. 
         [0008]    A weight of the flywheel, however, can become a factor in such torque ripple compensating devices. A lighter flywheel accelerates faster but also loses speed quicker, while a heavier flywheel retain speeds better compared to the lighter flywheel, but the heavier flywheel is more difficult to slow down. However, a heavier flywheel provides a smoother power delivery, but makes an associated engine less responsive, and an ability to precisely control an operating speed of the engine is reduced. 
         [0009]    In addition to a weight of the flywheel, another problem with conventional inertia and damping systems is a lack of adaptability. The conventional inertia and damping systems are designed for the worst operational condition and must be large enough to dampen vibrations at lower operating speeds. As a result, the conventional inertia and damping systems are not optimized for higher operating speeds, resulting in inadequate performance. 
         [0010]    It would be advantageous to develop a torque ripple compensating device able to be passively or dynamically adapted for both an amplitude and a phase of a torque ripple while minimizing an interference with an operation of an internal combustion engine. 
       SUMMARY OF THE INVENTION 
       [0011]    Presently provided by the invention, a torque ripple compensating device able to be passively or dynamically adapted for both an amplitude and a phase of a torque ripple while minimizing an interference with an operation of an internal combustion engine, has surprisingly been discovered. 
         [0012]    In one embodiment, the present invention is directed to a torsional compensating device for an internal combustion engine. The torsional compensating device comprises a first joint assembly and a torsional element. The first joint assembly is in driving engagement with an output of the internal combustion engine. The torsional element is in driving engagement with the first joint assembly and the output of the internal combustion engine. An angular deviation of the first joint assembly causes a cyclical acceleration of the torsional element. The cyclical acceleration of the torsional element applies a torque to the output of the internal combustion engine. 
         [0013]    In another embodiment, the present invention is directed to a torsional compensating device for an internal combustion engine. The torsional compensating device comprises a first Cardan joint assembly and a torsional element. The first Cardan joint assembly is in driving engagement with an output of the internal combustion engine. The torsional element is in driving engagement with the first Cardan joint assembly and the output of the internal combustion engine. The torsional element is oriented substantially parallel to the output of the internal combustion engine. An angular deviation of the first Cardan joint assembly causes a cyclical acceleration of the torsional element. The cyclical acceleration of the torsional element applies a torque to the output of the internal combustion engine. 
         [0014]    In yet another embodiment, the present invention is directed to a torsional compensating device for an internal combustion engine. The torsional compensating device comprises a first Cardan joint assembly, a second joint assembly, a clutching device, and a torsional element. The first Cardan joint assembly is in driving engagement with an output of the internal combustion engine. The second joint assembly is in driving engagement with the first Cardan joint assembly. The clutching device is in driving engagement with the second joint assembly. The torsional element is in driving engagement with the clutching device and the output of the internal combustion engine. The torsional element is oriented substantially parallel to the output of the internal combustion engine. An angular deviation of the first Cardan joint assembly causes a cyclical acceleration of the torsional element. The cyclical acceleration of the torsional element applies a torque to the output of the internal combustion engine. 
         [0015]    Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0016]    The above, as well as other advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which: 
           [0017]      FIG. 1  is a graph illustrating a torque output of an engine during a four stroke cycle of an engine; 
           [0018]      FIG. 2  is a sectional view of a flywheel based damping system known in the prior art; 
           [0019]      FIG. 3  is a schematic illustration of a torsional compensating device according to a first embodiment of the present invention; 
           [0020]      FIG. 4  is a schematic illustration of a torsional compensating device according to a second embodiment of the present invention; 
           [0021]      FIG. 5  is a schematic illustration of a torsional compensating device according to a third embodiment of the present invention; 
           [0022]      FIG. 6A  is a schematic illustration of the torsional compensating device shown in  FIG. 3  in a non-rotated position; and 
           [0023]      FIG. 6B  is a schematic illustration of the torsional compensating device shown in  FIG. 3  in a rotated position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. 
         [0025]      FIG. 3  illustrates a torsional compensating device  100 . The torsional compensating device  100  comprises a first gear  102 , a first joint assembly  104 , an intermediate shaft  106 , a second joint assembly  108 , a torsional element  110 , and a second gear  112 . The torque ripple compensating device  100  is in driving engagement with a main shaft  114  of an internal combustion engine  116 . The main shaft  114  is also in driving engagement with a transmission  118 . The torsional compensating device  100  is rotatably disposed in a housing  120  between the internal combustion engine  116  and the transmission  118 ; however, it is understood that the torsional compensating device  100  may be disposed in a portion of the internal combustion engine  116  or the transmission  118 . The internal combustion engine  116 , the torque compensating device  100 , and the transmission  118  form a portion of a vehicle (not shown); however, it is understood that the torque compensating device  100  may be used with an internal combustion engine in other applications. The first gear  102  and the second gear  112  of the torsional compensating device  100  are each in driving engagement with the main shaft  114  of the internal combustion engine  116 . 
         [0026]    The internal combustion engine  116  applies power to the main shaft  114  through a crankshaft (not shown). The internal combustion engine  116 , for example, is a four cycle internal combustion engine; however, it is understood that the internal combustion engine  116  may be another type of internal combustion engine that generates a torque ripple. It is understood that the internal combustion engine  116  may be a hybrid power source including both an internal combustion engine and an electric motor. 
         [0027]    The main shaft  114  is in driving engagement with the internal combustion engine  116  and a transmission  118 . The main shaft  114  may form a portion of one of the internal combustion engine  116  and the transmission  118 , or the main shaft  114  may be formed separate therefrom. The main shaft  114  is in driving engagement with the internal combustion engine  116  and the transmission  118  through splined connections formed on each end thereof; alternately, it is understood that the main shaft  114  may be in driving engagement with the internal combustion engine  116  and the transmission  118  in any other conventional manner. The main shaft  114  includes a first geared portion  122  and a second geared portion  124 . 
         [0028]    The first geared portion  122  is in driving engagement with the main shaft  114  through a splined connection; alternately, it is understood that the first geared portion  122  may be in driving engagement with the main shaft  114  in any other conventional manner. The first geared portion  122  is a spur gear in driving engagement with the first gear  102  of the torsional compensating device  100 ; however, it is understood that the first geared portion  122  may be in driving engagement with the first gear  102  of the torsional compensating device  100  through another type of gearing. 
         [0029]    The second geared portion  124  is in driving engagement with the main shaft  114  through a splined connection; alternately, it is understood that the second geared portion  124  may be in driving engagement with the main shaft  114  in any other conventional manner. The second geared portion  124  is a spur gear in driving engagement with the second gear  112  of the torsional compensating device  100 ; however, it is understood that the second geared portion  124  may be in driving engagement with the second gear  112  of the torsional compensating device  100  through another type of gearing. 
         [0030]    The transmission  118  facilitates driving engagement between the main shaft  114  of the internal combustion engine  116  and a ground engaging device (not shown) in a plurality of drive ratios. The transmission  118  may be an automatic transmission, a manual transmission, a continuously variable transmission, or another type of transmission. As known in the art, the transmission  118  may include a clutching device (not shown). 
         [0031]    The first gear  102  is rotatably disposed within the housing  120 . The first gear  102  is rotatably supported by bearings (not shown). The first gear  102  is a spur gear in driving engagement with the first gear portion  122  of the main shaft  114 ; however, it is understood that the first gear  102  may be in driving engagement with the first gear portion  122  of the main shaft  114  through another type of gearing. The first gear  102  in driving engagement with the first gear portion  122  forms a first drive ratio. The first gear  102  is also in driving engagement with the first joint assembly  104 . The first gear  102  is in driving engagement with the first joint assembly  104  through a splined connection; however, it is understood that the first gear  102  may be unitarily formed with the first joint assembly  104  or that the first gear  102  may be in driving engagement with the first joint assembly  104  in any conventional manner. 
         [0032]    The first joint assembly  104  facilitates driving engagement between the first gear  102  and first intermediate shaft  106 . The first joint assembly  104  may be a homokinetic or a non-homokinetic joint assembly. When the first joint assembly  104  is a non-homokinetic joint assembly, the first joint assembly  104  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the first joint assembly  104  is a non-homokinetic joint assembly, the first joint assembly  104  may be any type of non-homokinetic joint. When the first joint assembly  104  is a homokinetic joint assembly, the first joint assembly  104  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the first joint assembly  104  is a homokinetic joint assembly, the first joint assembly  104  may be any type of homokinetic joint. For simplicity, the components of the first joint assembly  104  are represented schematically in  FIG. 3 . 
         [0033]    When the first joint assembly  104  is a Cardan joint assembly, the first joint assembly  104  comprises a first driving yoke (not shown), a first cross-shaft (not shown), and a first driven yoke (not shown). The Cardan joint assembly is conventional and well known in the art. The first joint assembly  104  facilitates driving engagement between the first gear  102  and the intermediate shaft  106 . In the first joint assembly  104 , a relation between the first driving yoke and the first driven yoke may be described using the following equation: 
         [0000]      tan(β 1 )=cos(θ)tan(β)
 
         [0000]    In the above equation, θ is the angle between the first driving yoke and the first driven yoke, β is the angle of rotation of the first driving yoke and β 1  is the angle of rotation of the first driven yoke. Furthermore, as the angles of rotation are different for the first driving yoke and the first driven yoke, the rotation speeds and accelerations will also be slightly different. The relation between the two rotational speeds is the following: 
         [0000]    
       
         
           
             
               ω 
               1 
             
             = 
             
               
                 ω 
                  
                 
                     
                 
                  
                 cos 
                  
                 
                     
                 
                  
                 
                   ( 
                   θ 
                   ) 
                 
               
               
                 1 
                 - 
                 
                   
                     
                       sin 
                       2 
                     
                      
                     
                       ( 
                       β 
                       ) 
                     
                   
                    
                   
                     
                       sin 
                       2 
                     
                      
                     
                       ( 
                       θ 
                       ) 
                     
                   
                 
               
             
           
         
       
     
         [0000]    In the above equation, ω is the rotational speed of the first driving yoke and ω 1  is the rotational speed of the first driven yoke. A speed difference and an acceleration of the first driven yoke may be described using a second order phenomenon (sinusoidal with a period of 180°). 
         [0034]    The first driving yoke is a rigid member in driving engagement with the first gear  102  and the first cross-shaft. The first driving yoke is a substantially U-shaped member, but it is understood that the first driving yoke may have other shapes. The first driving yoke defines a pivot point which the first cross-shaft is rotatably coupled to. 
         [0035]    The first cross-shaft is a rigid member in driving engagement with the first driving yoke and the first driven yoke. The first cross-shaft is a cross shaped member comprising a pair of primary trunnions and a pair of secondary trunnions, oriented transversely to one another. The first driving yoke is rotatably coupled to the primary trunnions of the first cross-shaft and the first driven yoke is rotatably coupled to the secondary trunnions of the first cross-shaft. Bearings (not shown) may be disposed between each of the trunnions and the first driving yoke and the first driven yoke. 
         [0036]    The first driven yoke is a rigid member in driving engagement with the first cross shaft and the intermediate shaft  106 . The first driven yoke is a substantially U-shaped member, but it is understood that the first driven yoke may have other shapes. The first driven yoke defines a pivot point which the first cross-shaft is rotatably coupled to. 
         [0037]    The intermediate shaft  106  is rotatably disposed within the housing  120 . The intermediate shaft  106  may be rotatably supported by bearings (not shown). The intermediate shaft  106  is a rigid member in driving engagement with the first joint assembly  104  and the second joint assembly  108 . The intermediate shaft  106  is in driving engagement with the first joint assembly  104  through a splined connection; however, it is understood that the intermediate shaft  106  may be unitarily formed with the first joint assembly  104  or that the intermediate shaft  106  may be in driving engagement with the first joint assembly  104  in any conventional manner. The intermediate shaft  106  is in driving engagement with the second joint assembly  108  through a splined connection; however, it is understood that the intermediate shaft  106  may be unitarily formed with the second joint assembly  108  or that the intermediate shaft  106  may be in driving engagement with the second joint assembly  108  in any conventional manner. It is also understood that in embodiments of the invention not shown, the torsional compensating device  100  may not include the intermediate shaft  106 . In such embodiments, the first joint assembly  104  is directly drivingly engaged with the second joint assembly  108 . 
         [0038]    The second joint assembly  108  facilitates driving engagement between the intermediate shaft  106  and the torsional element  110 . The second joint assembly  108  may be a homokinetic or a non-homokinetic joint assembly. When the second joint assembly  108  is a non-homokinetic joint assembly, the second joint assembly  108  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the second joint assembly  108  is a non-homokinetic joint assembly, the second joint assembly  108  may be any type of non-homokinetic joint. When the second joint assembly  108  is a homokinetic joint assembly, the second joint assembly  108  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the second joint assembly  108  is a homokinetic joint assembly, the second joint assembly  108  may be any type of homokinetic joint. For simplicity, the components of the second joint assembly  108  are represented schematically in  FIG. 3 . 
         [0039]    When the joint assemblies  104 ,  108  are Cardan joint assemblies, it is understood that the second joint assembly  108  is not phased in relation to the first joint assembly  104  to cancel a speed difference and an acceleration of the intermediate shaft  106  caused by the first joint assembly  104 . Further, it is understood that the second joint assembly  108  may be phased similarly to the first joint assembly  104  or that the second joint assembly  108  may be phased partially similar to the first joint assembly  104 . An angle of the second joint assembly  108  is substantially equal to an angle of the first joint assembly  104 . 
         [0040]    When one of the joint assemblies  104 ,  108  is not a Cardan joint assembly, it is understood that at least one of the joint assemblies  104 ,  108  is not phased in relation to a remaining one of the joint assemblies  104 ,  108 . Phasing one of the joint assemblies  104 ,  108  in relation to a remaining one of the joint assemblies  104 ,  108  may be performed by selecting a non-homokinetic joint as one of the joint assemblies  104 ,  108 . 
         [0041]    The torsional element  110  is a semi-rigid member in driving engagement with the second joint assembly  108  and the second gear  112 . The torsional element  110  is oriented substantially parallel to the main shaft  114 . The torsional element  110  comprises a torsion bar or a torsion spring to facilitate an angular deviation between the second joint assembly  108  and the second gear  112 . In response to the angular deviation between the second joint assembly  108  and the second gear  112 , the torsional element  110  generates a torque, which is applied to the second gear  112 . The following equation may be used to calculate a torque generated by the torsional element  110 : 
         [0000]        T=K ·Δ(β)
 
         [0000]    in which T is the torque generated by the torsional element  110 , Δ(β) is an angular deviation applied to the torsional element  110  through the first joint assembly  104  and the second joint assembly  108 , and K is a spring constant associated with the torsional element  110 . 
         [0042]    As the angular deviation generated by the first joint assembly  104  and the second joint assembly  108  is a second order deviation, the torque generated by the torsional element  110  will be a second order torque oscillation. The torque generated by the torsional element  110  is used to damp a torque ripple produced by the internal combustion engine  116 . As a non-limiting example, a four-cylinder internal combustion engine produces a greatest torque ripple four times for every two rotations of the internal combustion engine, thus such a torque ripple may be described as a second order torque peak. 
         [0043]    The second gear  112  is rotatably disposed within the housing  120 . The second gear  112  is rotatably supported by bearings (not shown). The second gear  112  is a spur gear in driving engagement with the second gear portion  124  of the main shaft  114 ; however, it is understood that the second gear  112  may be in driving engagement with the second gear portion  124  of the main shaft  114  through another type of gearing. The second gear  112  in driving engagement with the second gear portion  124  forms a second drive ratio. It is understood that the second drive ratio is equal to the first drive ratio. The second gear  112  is also in driving engagement with the first joint assembly  104 . The first gear  102  is in driving engagement with the first torsional element  110  through a splined connection; however, it is understood that the second gear  112  may be unitarily formed with the torsional element  110  or that the second gear  112  may be in driving engagement with the torsional element  110  in any conventional manner. 
         [0044]      FIG. 4  illustrates a torsional compensating device  200 . The torque ripple compensating device  200  is a variation of the torque ripple compensating device  100 , and has similar features thereto. The variation of the invention shown in  FIG. 4  includes similar components to the torque ripple compensating device  100  illustrated in  FIG. 3 . Similar features of the variation shown in  FIG. 4  are numbered similarly in series, with the exception of the features described below. 
         [0045]    The torsional compensating device  200  comprises a first gear  202 , a first joint assembly  204 , an intermediate shaft  206 , a second joint assembly  230 , a clutching device  232 , a torsional element  234 , and a second gear  212 . The torque ripple compensating device  200  is in driving engagement with a main shaft  214  of an internal combustion engine  216 . The main shaft  214  is also in driving engagement with a transmission  218 . The torsional compensating device  200  is rotatably disposed in a housing  220  between the internal combustion engine  216  and the transmission  218 ; however, it is understood that the torsional compensating device  200  may be disposed in a portion of the internal combustion engine  216  or the transmission  218 . The internal combustion engine  216 , the torque compensating device  200 , and the transmission  218  form a portion of a vehicle (not shown); however, it is understood that the torque compensating device  200  may be used with an internal combustion engine in other applications. The first gear  202  and the second gear  212  of the torsional compensating device  200  are each in driving engagement with the main shaft  214  of the internal combustion engine  216 . 
         [0046]    The second joint assembly  230  facilitates driving engagement between the intermediate shaft  206  and the clutching device  232 . The second joint assembly  230  may be a homokinetic or a non-homokinetic joint assembly. When the second joint assembly  230  is a non-homokinetic joint assembly, the second joint assembly  230  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the second joint assembly  230  is a non-homokinetic joint assembly, the second joint assembly  230  may be any type of non-homokinetic joint. When the second joint assembly  230  is a homokinetic joint assembly, the second joint assembly  230  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the second joint assembly  230  is a homokinetic joint assembly, the second joint assembly  230  may be any type of homokinetic joint. For simplicity, the components of the second joint assembly  230  are represented schematically in  FIG. 3 . 
         [0047]    When the joint assemblies  204 ,  230  are Cardan joint assemblies, it is understood that the second joint assembly  230  is not phased in relation to the first joint assembly  204  to cancel a speed difference and an acceleration of the intermediate shaft  206  caused by the first joint assembly  204 . Further, it is understood that the second joint assembly  230  may be phased similarly to the first joint assembly  204  or that the second joint assembly  230  may be phased partially similar to the first joint assembly  204 . An angle of the second joint assembly  230  is substantially equal to an angle of the first joint assembly  204 . When one of the joint assemblies  204 ,  230  is not a Cardan joint assembly, it is understood that at least one of the joint assemblies  204 ,  230  is not phased in relation to a remaining one of the joint assemblies  204 ,  230 . Phasing one of the joint assemblies  204 ,  230  in relation to a remaining one of the joint assemblies  204 ,  230  may be performed by selecting a non-homokinetic joint as one of the joint assemblies  204 ,  230 . 
         [0048]    The clutching device  232  facilitates variable driving engagement between the second joint assembly  230  and the torsional element  234 ; however, it is understood that the clutching device  232  may be positioned at another location in the torsional compensating device  200 . The clutching device  232  is a plate style clutch; however, it is understood that the clutching device  232  may be a cone style clutch or another type of clutching device that can be variably engaged. The clutching device  232  is in communication with a control system (not shown) to control an engagement level of the clutching device  232 . Typically, the clutching device  232  is in an engaged position and the clutching device  232  is only variably engaged to adjust a relationship between the second joint assembly  230  and the torsional element  234 . When the relationship between the second joint assembly  230  and the torsional element  234  is adjusted, the clutching device  232  is placed in a “slipping” condition. Typically, the relationship between the second joint assembly  230  and the torsional element  234  is adjusted in very small increments. 
         [0049]    Further, it is understood that by disengaging the clutching device  232 , a torque generated by the torsional compensating device  200  can be eliminated. Disengaging the clutching device  232  may be preferable at higher operating speeds of the internal combustion engine  216 , when a torque ripple produced by the internal combustion engine  216  is less severe, for example. 
         [0050]    The torsional element  234  is a semi-rigid member in driving engagement with the second joint assembly  230  and the second gear  212 . The torsional element  234  is oriented substantially parallel to the main shaft  214 . The torsional element  234  comprises a torsion bar or a torsion spring to facilitate an angular deviation between the clutching device  232  and the second gear  212 . In response to the angular deviation between the second joint assembly  230  and the second gear  212 , the torsional element  234  generates a torque, which is applied to the second gear  212 . The equation presented above may be used to calculate a torque generated by the torsional element  234 . 
         [0051]    As the angular deviation generated by the first joint assembly  204  and the second joint assembly  230  is a second order deviation, the torque generated by the torsional element  234  will be a second order torque oscillation. The torque generated by the torsional element  234  is used to damp a torque ripple produced by the internal combustion engine  216 . As a non-limiting example, a four-cylinder internal combustion engine produces a greatest torque ripple four times for every two rotations of the internal combustion engine, thus such a torque ripple may be described as a second order torque peak. 
         [0052]      FIG. 5  illustrates a torsional compensating device  300 . The torque ripple compensating device  300  is a variation of the torque ripple compensating device  100 , and has similar features thereto. The variation of the invention shown in  FIG. 5  includes similar components to the torque ripple compensating device  100  illustrated in  FIG. 3 . Similar features of the variation shown in  FIG. 5  are numbered similarly in series, with the exception of the features described below. 
         [0053]    The torsional compensating device  300  comprises a first gear  302 , a first joint assembly  340 , a first intermediate shaft  342 , a second joint assembly  344 , a second intermediate shaft  346 , a third joint assembly  348 , a joint actuator  350 , a torsional element  352 , and a second gear  312 . The torque ripple compensating device  300  is in driving engagement with a main shaft  314  of an internal combustion engine  316 . The main shaft  314  is also in driving engagement with a transmission  318 . The torsional compensating device  300  is rotatably disposed in a housing  320  between the internal combustion engine  316  and the transmission  318 ; however, it is understood that the torsional compensating device  300  may be disposed in a portion of the internal combustion engine  316  or the transmission  318 . The internal combustion engine  316 , the torque compensating device  300 , and the transmission  318  form a portion of a vehicle (not shown); however, it is understood that the torque compensating device  300  may be used with an internal combustion engine in other applications. The first gear  302  and the second gear  312  of the torsional compensating device  300  are each in driving engagement with the main shaft  314  of the internal combustion engine  316 . 
         [0054]    The first joint assembly  340  facilitates driving engagement between the first gear  302  and first intermediate shaft  342 . The first joint assembly  340  may be a homokinetic or a non-homokinetic joint assembly. When the first joint assembly  340  is a non-homokinetic joint assembly, the first joint assembly  340  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the first joint assembly  340  is a non-homokinetic joint assembly, the first joint assembly  340  may be any type of non-homokinetic joint. When the first joint assembly  340  is a homokinetic joint assembly, the first joint assembly  340  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the first joint assembly  340  is a homokinetic joint assembly, the first joint assembly  340  may be any type of homokinetic joint. 
         [0055]    The first intermediate shaft  342  is rotatably disposed within the housing  320 . The first intermediate shaft  342  may be rotatably supported by bearings (not shown). The first intermediate shaft  342  is a rigid member in driving engagement with the first joint assembly  340  and the second joint assembly  344 . The first intermediate shaft  342  is a telescoping shaft which facilitates adjusting a position of the second joint assembly  344  with respect to the first joint assembly  340 . The first intermediate shaft  342  is in driving engagement with the first joint assembly  340  through a splined connection; however, it is understood that the first intermediate shaft  342  may be unitarily formed with the first joint assembly  340  or that the first intermediate shaft  342  may be in driving engagement with the first joint assembly  340  in any conventional manner. The first intermediate shaft  342  is in driving engagement with the second joint assembly  344  through a splined connection; however, it is understood that the first intermediate shaft  342  may be unitarily formed with the second joint assembly  344  or that the first intermediate shaft  342  may be in driving engagement with the second joint assembly  344  in any conventional manner. It is also understood that in embodiments of the invention not shown, the torsional compensating device  300  may not include the first intermediate shaft  342 . In such embodiments, the first joint assembly  340  is directly drivingly engaged with the second joint assembly  344  in a telescoping manner. 
         [0056]    The second joint assembly  344  facilitates driving engagement between the first intermediate shaft  342  and the second intermediate shaft  346 . The second joint assembly  344  may be a homokinetic or a non-homokinetic joint assembly. When the second joint assembly  344  is a non-homokinetic joint assembly, the second joint assembly  344  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the second joint assembly  344  is a non-homokinetic joint assembly, the second joint assembly  344  may be any type of non-homokinetic joint. When the second joint assembly  344  is a homokinetic joint assembly, the second joint assembly  344  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the second joint assembly  344  is a homokinetic joint assembly, the second joint assembly  344  may be any type of homokinetic joint. 
         [0057]    The second intermediate shaft  346  is rotatably disposed within the housing  320 . The second intermediate shaft  346  may be rotatably supported by bearings (not shown). The second intermediate shaft  346  is a rigid member in driving engagement with the second joint assembly  344  and the third joint assembly  348 . The second intermediate shaft  346  is a telescoping shaft which facilitates adjusting a position of the second joint assembly  344  with respect to the third joint assembly  348 . The second intermediate shaft  346  is in driving engagement with the second joint assembly  344  through a splined connection; however, it is understood that the second intermediate shaft  346  may be unitarily formed with the second joint assembly  344  or that the second intermediate shaft  346  may be in driving engagement with the second joint assembly  344  in any conventional manner. The second intermediate shaft  346  is in driving engagement with the third joint assembly  348  through a splined connection; however, it is understood that the second intermediate shaft  346  may be unitarily formed with the third joint assembly  348  or that the second intermediate shaft  346  may be in driving engagement with the third joint assembly  348  in any conventional manner. It is also understood that in embodiments of the invention not shown, the torsional compensating device  300  may not include the second intermediate shaft  346 . In such embodiments, the second joint assembly  344  is directly drivingly engaged with the third joint assembly  348  in a telescoping manner. 
         [0058]    The third joint assembly  348  facilitates driving engagement between the second intermediate shaft  346  and the torsional element  352 . The third joint assembly  348  may be a homokinetic or a non-homokinetic joint assembly. When the third joint assembly  348  is a non-homokinetic joint assembly, the third joint assembly  348  may be a Cardan joint assembly, as described hereinabove. Further, it is understood that when the third joint assembly  348  is a non-homokinetic joint assembly, the third joint assembly  348  may be any type of non-homokinetic joint. When the third joint assembly  348  is a homokinetic joint assembly, the third joint assembly  348  may be a constant velocity joint assembly, which is conventional and well known in the art. Further, it is understood that when the third joint assembly  348  is a homokinetic joint assembly, the third joint assembly  348  may be any type of homokinetic joint. 
         [0059]    It is understood that at least one of the second joint assembly  344  and the third joint assembly  348  is not phased in relation to the first joint assembly  340 . Phasing one of the second joint assembly  344  and the third joint assembly  348  in relation to the first joint assembly  340  may be performed by selecting a non-homokinetic joint as at least one of the first joint assembly  340 , the second joint assembly  344 , and the third joint assembly  348 ; however, it is understood that the two or all of the joint assemblies  340 ,  344 ,  348  may be non-homokinetic joints, as long as the joint assemblies  340 ,  344 ,  348  are arranged to not cancel a speed difference and an acceleration of a portion of the third joint assembly  348  in driving engagement with the torsional element  352  compared to a portion of the first joint assembly  340  in driving engagement with the first gear  202 . 
         [0060]    The torsional element  352  is a semi-rigid member in driving engagement with the third joint assembly  348  and the second gear  312 . The torsional element  352  is oriented substantially parallel to the main shaft  314 . The torsional element  352  comprises a torsion bar or a torsion spring to facilitate an angular deviation between the third joint assembly  348  and the second gear  312 . In response to the angular deviation between the third joint assembly  348  and the second gear  312 , the torsional element  352  generates a torque, which is applied to the second gear  312 . The equation presented above may be used to calculate a torque generated by the torsional element  352 . 
         [0061]    The joint actuator  350  is an actuator in driving engagement with the second joint assembly  344  and the housing  320 . The joint actuator  350  may be a hydraulic actuator, a pneumatic actuator, a screw driven actuator, or any other type of known actuator. In response to a control signal from a controller (not shown), the joint actuator  350  applies a force to the second joint assembly  344  to move the second joint assembly  344  with respect to the first joint assembly  340  and the third joint assembly  348 , changing an angle of each of the joint assemblies  340 ,  344 ,  348  and a length of the intermediate shafts  342 ,  346 . In response to the second joint assembly  344  being moved with respect to the first joint assembly  340  and the third joint assembly  348 , a speed difference and an acceleration of a portion of the third joint assembly  348  is adjusted compared to a portion of the first joint assembly  340  in driving engagement with the first gear  202 , thus changing an amplitude of a torque applied to the second gear  312  generated by the torsional element  352 . 
         [0062]    It is also understood that as an alternative to the embodiments of the invention described herein, a variation of the torsional compensating device  300  including four joint assemblies, in which a joint actuator moves a shaft portion of the torsional compensating device in a manner parallel to a main shaft, is within the scope of the present invention. 
         [0063]    In use, the torsional compensating device  100 ,  200 ,  300  generates a torque using the torsional element  110 ,  234 ,  352  and at least one of the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348  to damp a torque ripple produced by the internal combustion engine  116 ,  216 ,  316 . The torsional compensating device  100 ,  200 ,  300  is a parallel, torque additive device for the internal combustion engine  116 ,  216 ,  316 . 
         [0064]    To ensure that a torque generated by the torsional compensating device  100 ,  200 ,  300  is correcting the torque ripple produced by the internal combustion engine  116 ,  216 ,  316  and not increasing the torque ripple produced by the internal combustion engine  116 ,  216 ,  316 , a phase at which the torsional compensating device  100 ,  200 ,  300  operates at must be set to a correct value. A phase at which the torsional compensating device  100 ,  200 ,  300  operates at may be adjusted dynamically or may be set by a design and orientation of the torsional compensating device  100 ,  200 ,  300  in applications in which dynamic phase adjustment is not necessary. When a design and orientation of the torsional compensating device  100 ,  200 ,  300  determines a phase, a position of the torsional compensating device  100 ,  200 ,  300  with respect to a crankshaft angle of the internal combustion engine  116 ,  216 ,  316  determined the phase. The position of the torsional compensating device  116 ,  216 ,  316  is determined by a position of a plane formed by the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348  compared to a plane of the crankshaft of the internal combustion engine  116 ,  216 ,  316 . As a non-limiting example, if the plane formed by the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348  is the same as a plane of a plurality of pistons of the internal combustion engine  116 ,  216 ,  316 , the torsional compensating device  100 ,  200 ,  300  will have a phase substantially equal to 0 degrees, while placing the plane formed by the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348  inclined compared to the plane of a plurality of pistons will create some de-phasing. 
         [0065]    A phase at which the torsional compensating device  100 ,  200 ,  300  operates at may be adjusted dynamically. A first way in which a phase of the torsional compensating device  200  may be adjusted dynamically during the operation of the torsional compensating device  200  is through the operation of the clutching device  232 . As described hereinabove, by disengaging the clutching device  232 , the clutching device  232  is placed in a “slipping” condition. When the clutching device  232  is placed in a “slipping” condition, the relationship between the second joint assembly  230  and the torsional element  234  is adjusted, resulting in an adjustment to a phase of the torsional compensating device  200 . 
         [0066]    A second way in which a phase of the torsional compensating device  100 ,  200 ,  300  may be adjusted dynamically during the operation of the torsional compensating device  100 ,  200 ,  300  is through rotation of the torsional compensating device  100 ,  200 ,  300  about the main shaft  114 ,  214 ,  314 .  FIGS. 6A and 6B  illustrates the torsional compensating device  100  in both a non-rotated position and a rotated position. It is understood that the torsional compensating device  200 ,  300  may be rotated similarly. A phase actuator  400  facilitates rotating the torsional compensating device  100  about the main shaft  114 . In rotating the torsional compensating device  100  about the main shaft  114 , the plane formed by the joint assemblies  104 ,  108  is adjusted from the plane of a plurality of pistons of the internal combustion engine  116 . By rotating the torsional compensating device  100 , a de-phasing occurs between a torque generated by the torsional compensating device  100  and the torque ripple produced by the internal combustion engine  116 . It is understood that rotating the torsional compensating device  100 ,  200 ,  300  may be performed prior to operation of the internal combustion engine  116 ,  216 ,  316 , performed dynamically during operation of the internal combustion engine  116 ,  216 ,  316 , or incorporated into a fixed design of the torsional compensating device  100 ,  200 ,  300 . 
         [0067]    It is also understood that as an alternative to the embodiments of the invention described herein, it is within the scope of the present invention for alternative drive ratios to be incorporated into the torsional compensating device  100 ,  200 ,  300 . As described hereinabove, a gear ratio of 1:1 between the first geared portion  122 ,  222 ,  322  and the first gear  102 ,  202 ,  302  and the second geared portion  124 ,  224 ,  324  and the second gear  112 ,  212 ,  312  is useful to damp second order torque ripples produced by the internal combustion engine  116 ,  216 ,  316 , as joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348  introduce a second order speed oscillation. Such a gear ratio is useful for a four cylinder engine, in which a biggest torque ripple occurs at the second order. As a non-limiting example, a gear ratio of 1:1.5 between the first geared portion  122 ,  222 ,  322  and the first gear  102 ,  202 ,  302  and the second geared portion  124 ,  224 ,  324  and the second gear  112 ,  212 ,  312  is also useful. In such a variation, the first gear  102 ,  202 ,  302  would be driven one and a half times as fast as the main shaft  114 ,  214 ,  314 , and torque corrections generated by the torsional compensating device  100 ,  200 ,  300  would occur at the third order. Torque corrections occurring at the third order could be used to damp a torque ripple of the internal combustion engine  116 ,  216 ,  316  having three cylinders, and thus a torque ripple that occurs three times every two turns. 
         [0068]    As described hereinabove, it is within the scope of the present invention for the torsional compensating device  100 ,  200 ,  300  to include a single non-homokinetic joint as one of the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348 . A remaining joint assembly  104 ,  108 ,  204 ,  230  or joint assemblies  340 ,  344 ,  348  would be a homokinetic joint as described hereinabove. Such a torsional compensating device  100 ,  200 ,  300  would be useful in applications in which torque ripples produced by the internal combustion engine  116 ,  216 ,  316  are relatively small. An amplitude of torque peaks created by such a torsional compensating device  100 ,  200 ,  300  would be smaller than a torsional compensating device  100 ,  200 ,  300  including two non-homokinetic joints. 
         [0069]    Based on the foregoing, it can be appreciated that the torsional compensating device  100 ,  200 ,  300  described and depicted herein has several advantages over the known art. Some of the advantages of the torsional compensating device  100 ,  200 ,  300  include, but are not limited to, the torsional compensating device  100 ,  200 ,  300  that can be actively regulated in phase and amplitude and the torsional compensating device  100 ,  200 ,  300  is formed from common and cost effective components. Additionally, the torsional compensating device  100 ,  200 ,  300  is a configurable design, which affords significant flexibility through a selection of the torsional element  110 ,  234 ,  352  and an angle of the joint assemblies  104 ,  108 ,  204 ,  230 ,  340 ,  344 ,  348 . Further, the torsional compensating device  100 ,  200 ,  300  is a parallel additive torque device which does not dissipate an excessive amount of energy through frictional losses or through damping. 
         [0070]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.