Abstract:
Some exemplary embodiments include methods of operating a hybrid powertrain system including an engine and a motor/generator. One exemplary method includes sensing a characteristic of the motor/generator, determining a first net torque of the engine based upon a model, determining a second net torque of the engine based upon the characteristic of the motor/generator, and diagnosing the system based upon the first net torque and the second net torque. Further exemplary embodiments include hybrid powertrain methods, hybrid powertrain systems, and articles of manufacture configured to store computer executable instructions for hybrid powertrains. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Description:
BACKGROUND 
       [0001]    Hybrid powertrains including one or more internal combustion engines and one or more motor/generators can be used to provide motive power to vehicles. Such hybrid powertrains offer the potential for multiple advantages including reduced fuel consumption, reduced pollution and emissions, and greater operational flexibility among others. The advantages of hybrid systems have been limited by the significantly more complicated to control and diagnostic problems which they present. Present approaches to controls and diagnostics for hybrid powertrains suffer from a number of drawbacks, limitations, disadvantages and problems. There is a need for the unique and inventive hybrid powertrain diagnostics and controls disclosed herein. 
       SUMMARY 
       [0002]    Some exemplary embodiments include methods of operating a hybrid powertrain system including an engine and a motor/generator. One exemplary method includes sensing a characteristic of the motor/generator, determining a first net torque of the engine based upon a model, determining a second net torque of the engine based upon the characteristic of the motor/generator, and diagnosing the system based upon the first net torque and the second net torque. Further exemplary embodiments include hybrid powertrain methods, hybrid powertrain systems, and articles of manufacture configured to store computer executable instructions for hybrid powertrains. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0003]      FIG. 1  is a schematic diagram illustrating an exemplary hybrid powertrain system. 
           [0004]      FIG. 2  is a flowchart illustrating an exemplary process. 
           [0005]      FIG. 3  is a flowchart illustrating an exemplary process. 
           [0006]      FIG. 4  is a flowchart illustrating an exemplary process. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    For the purposes of clearly, concisely and exactly describing exemplary embodiments of the invention, the manner and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to the exemplary embodiments illustrated in the figures and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created, and that the invention includes and protects such alterations and modifications to the exemplary embodiments, and such further applications of the exemplary embodiments as would occur to one skilled in the art to which the invention relates. 
         [0008]    With reference to  FIG. 1  there is illustrated an exemplary hybrid powertrain system  100  which can provide operative or motive power for vehicle such as a passenger car, truck, bus, off-highway vehicle, construction vehicle, mining vehicle, train, ship or other type of vehicle. Hybrid powertrain system  100  includes internal combustion engine  110  and motor/generator  120 . As illustrated in  FIG. 1 , engine  110  and motor/generator  120  are configured in a series-parallel relationship examples of which include a power split hybrid configuration and a combined hybrid configuration. In other embodiments engine  110  and motor/generator  120  are configured in a series relationship. In an exemplary series configuration engine  110  drives motor/generator  120  which outputs electrical power which can be stored and/or used to provide motive power for a vehicle. In other embodiments engine  110  and motor/generator  120  are configured in a parallel relationship. In an exemplary parallel configuration engine  110  and motor/generator  120  are selectably operable to power a vehicle powertrain alone or in combination. 
         [0009]    As illustrated in  FIG. 1 , engine  110  and motor/generator  120  can operate in multiple modes to output torque to differential  140  which, in turn outputs torque to wheels  150 . In some modes of operation, the net torque output from engine  110  is delivered to motor/generator  120 . In other modes of operation, the net torque output from engine  110  is delivered to differential  140 . In other modes of operation, engine  110  delivers a portion of its net torque to motor/generator  120  and a portion of its net torque output to differential  140 . Engine  110  is also selectably operable to drive compressor  111 , fan  112 , and other engine accessories  113  which can include, for example, alternator(s), additional compressor(s), additional fan(s) and other engine accessories. 
         [0010]    System  100  includes a control module  130  which is operable to control the operation of system  100 . Control module  130  is coupled with a number of communication links, examples of which are illustrated as dashed lines, for sending and receiving signals or information to and from other components of system  100 , including engine  110 , motor/generator  120 , compressor  111 , fan  112 , and other engine accessories  113 . 
         [0011]    Control module  130  is operable to determine a net torque of engine  110  based upon a fueling information input to a model. In one embodiment the model determines gross torque based upon fueling information, and determines a net torque by accounting for friction losses, pumping losses, cam losses, accessory losses and parasitics. Some embodiments utilize models which account for additional or alternate factors. As used herein net torque refers to a torque available to provide power to a powertrain. One definition of net torque is the torque at the main engine output shaft, sometimes referred to as brake torque. Other definitions include the torque at other locations such as the flywheel or driveplate. Still other definitions account for frictional and other losses present after engine output. Unless indicated otherwise, net torque includes these and other definitions of torque which connote the torque available to provide power to a powertrain regardless of the particular point at which such torque is defined or measured and regardless of the particular losses which are accounted for. 
         [0012]    Control module  130  is operable to determine the net toque of engine  110  based upon one or more characteristics of motor/generator  120 . In series modes of operation the net torque of engine  110  is delivered to motor/generator  120  and engine net torque can be determined based upon one or more electrical characteristics of motor/generator  120 . In some embodiments net torque is determined in accordance with the relationship τ=k*I*V/ω, where τ is torque, k is a constant, I is a generator current, V is a generator voltage, and ω is the angular velocity of the generator. In some embodiments 2π*n where n is the rotational speed can be used instead of ω. In some embodiments k may be selected to account for powertrain losses or other system losses. In some embodiments engine net torque is determined in accordance with the relationship τ=kI 2 *R/ω, where τ is torque, k is a constant, I is a motor/generator current, R is motor/generator resistance, and ω is the angular velocity of the generator. In some embodiments engine net torque is determined in accordance with non-linear equations which account for second or higher order effects, for example, the non-linear elastic shaft behavior (stress-strain deformations) that would accompany any shaft undergoing a torque, non-linear perturbations or oscillations, non-linear electromagnetic behavior of the electric motor system, engine torque oscillations due to firing order and uneven cylinder torque, and others. 
         [0013]    Engine net torque can be determined based upon characteristics of a motor/generator regardless of the mode of system operation or system configuration. In some embodiments generator acceleration, for example generator shaft acceleration, is measured at an rate effective to provide indicia of engine firing events. This rate permits engine net torque to be determined from shaft acceleration and system inertia in both series and non-series operation and in both series and non-series system configurations. In some embodiments the rate is about every two shaft revolutions. In some embodiments the rate is about every shaft revolution. In some embodiments the resolution is about a fraction of a shaft revolution, for example, a half, a third, a fourth, a fifth, a sixth or another fraction. In some embodiments engine net torque is determined in accordance with the relationship T=T 1 +J*dω/dt where T is the instantaneous value of the developed motor torque, T 1  is the instantaneous value of the load torque, w is the instantaneous angular velocity of the motor shaft, and J is the moment of inertia of the motor-load system. In some embodiments engine net torque is determined in accordance with non-linear equations which account for second or higher order effects such as those described above. 
         [0014]    In some embodiments engine net torque can be determined based upon one or more electrical characteristics of a motor/generator regardless of the mode of system operation or system configuration by operating a motor/generator to smooth torque pulsations which result from engine firing events. In some embodiments, a reciprocating piston engine generates torque pulses each time one of its cylinders fires and the engine net torque output includes pulses attributable to the firing events. A motor/generator is operatively coupled with the engine mechanical, electrical, or a combination of electrical and mechanical depending upon the system configuration. The motor/generator operates to smooth the torque pulses and smooth the engine net torque output. In an exemplary embodiment the motor/generator smoothes torque pulsations by increasing and decreasing its load on the engine to smooth the torque pulsations. This can be accomplished, for example, by charging and discharging a capacitor, supercapacitor, ultracapacitor, piezoelectric device or another device operable to store and release energy at a rate on the order of the torque pulses. The variation of motor/generator load to smooth torque pulsations is matched to expected torque pulsations based upon a model which can account for variables such as fueling, engine speed and other information relating to engine characteristics. Over or under correction of torque pulses results in a vibration of the system which can be sensed. In some embodiments amplitude and frequency of the torque pulses can be sensed. The amplitude and frequency of the vibration can be used to diagnose particular system malfunctions or errors. An electrical characteristic of the motor/generator can also be used to determine the net torque of the engine. This net torque can be used in combination with the vibration amplitude and frequency information to diagnose particular system malfunctions or errors. A difference between this net torque and a modeled net torque can also be used in combination with the vibration amplitude and frequency information to diagnose particular system malfunctions or errors. 
         [0015]    With reference to  FIG. 2  there is illustrated a flowchart according to an exemplary diagnostic process  200  which includes multiple operations that can be performed by a controller such as ECM  130  described above or one or more additional or alternate controllers. 
         [0016]    Operation  210  operates a hybrid powertrain system including one or more engine(s) and one or more motor/generator(s). The hybrid powertrain system may be system  100  described above or another hybrid powertrain system. The hybrid powertrain system may have a series configuration, a parallel configuration or a series/parallel configuration, and may operate in a series mode of operation, a parallel mode of operation, a series/parallel mode of operation or may vary among such modes of operation. From operation  210  process  200  proceeds to operation  220 . 
         [0017]    Operation  220  senses one or more electrical characteristics of a motor/generator of the hybrid powertrain system. Some embodiments sense one or more of the electrical characteristics described above. Some embodiments sense other electrical characteristics. From operation  220  process  200  proceeds to operation  230 . 
         [0018]    Operation  230  uses one or more sensed electrical characteristics of the motor/generator to determine a first net torque of the engine of the hybrid powertrain system. Some embodiments determine a first net torque of the engine based upon one or more relationships described above. Some embodiments determine a first net torque of the engine based upon other relationships. From operation  230  process  200  proceeds to operation  240 . 
         [0019]    Operation  240  uses a model to determine a second net torque of the engine of the hybrid powertrain system. Some embodiments determine gross torque based upon fueling information, and determine net torque by accounting for friction losses, pumping losses, cam losses, accessory losses and parasitics. Some embodiments utilize models which account for additional or alternate factors, for example, turbocharger information, engine speed information and others. In the illustrated example operation  240  is performed after operation  230 . In other embodiments operation  240  is performed before operation  220 , in parallel with operation  220 , before operation  230 , in parallel with operation  230 . From operation  240  process  200  proceeds to operation  250 . 
         [0020]    Operation  250  diagnoses the system based upon the first net torque and the second net torque. Some embodiments diagnose the system using additional information, for example, vibration characteristics such as those discussed above. Some embodiments include a two dimensional look up table which includes first net torque values on a first axis, second net torque values on a second axis, and specifies diagnostic conditions for table entries. Some embodiments include look up tables with greater or fewer numbers of axes, for example, a single axis of differences between the first torque values and the second torque values rather than separate axes for first net torque values and second net torque values. As used herein diagnosing, diagnostic(s), diagnosis and like terms include diagnosing current operational states, malfunctions, failures, and/or other conditions as well as future prognostics of such conditions. From operation  250  process  200  proceeds to operation  260  where process  200  returns to operation  210 , returns to another operation of process  200 , or ends. Operation  260  may also call for another process to be performed. 
         [0021]    With reference to  FIG. 3  there is illustrated a flowchart according to an exemplary diagnostic process  300  which includes multiple operations that can be performed by a controller such as ECM  130  described above or one or more additional or alternate controllers. 
         [0022]    Operation  310  operates a hybrid powertrain system including one or more engine(s) and one or more motor/generator(s). The hybrid powertrain system may be system  100  described above or another hybrid powertrain system. The hybrid powertrain system may have a series configuration, a parallel configuration or a series/parallel configuration, and may operate in a series mode of operation, a parallel mode of operation, a series/parallel mode of operation or may vary among such modes of operation. From operation  310  process  300  proceeds to operation  320 . 
         [0023]    Operation  320  senses one or more acceleration characteristics of a motor/generator of the hybrid powertrain system. Some embodiments sense one or more of the acceleration characteristics described above. Some embodiments sense other acceleration characteristics. From operation  320  process  300  proceeds to operation  330 . 
         [0024]    Operation  330  uses one or more sensed acceleration characteristics of the motor/generator to determine a first net torque of the engine of the hybrid powertrain system. Some embodiments determine a first net torque of the engine based upon one or more acceleration characteristics of the motor/generator described above. Some embodiments determine a first net torque of the engine based upon other acceleration characteristics of the motor/generator described above. From operation  330  process  300  proceeds to operation  340 . 
         [0025]    Operation  340  uses a model to determine a second net torque of the engine of the hybrid powertrain system. Some embodiments determine gross torque based upon fueling information, and determine net torque by accounting for friction losses, pumping losses, cam losses, accessory losses and parasitics. Some embodiments utilize models which account for additional or alternate factors, for example, turbocharger information, engine speed information and others. In the illustrated example operation  340  is performed after operation  330 . In other embodiments operation  340  is performed before operation  320 , in parallel with operation  320 , before operation  330 , in parallel with operation  330 . From operation  340  process  300  proceeds to operation  350 . 
         [0026]    Operation  350  diagnoses the system based upon the first net torque, the second net torque. Some embodiments diagnose the system using additional information, for example, vibration characteristics, such as those discussed above. Some embodiments include a four dimensional look up table which includes first net torque values on a first axis, second net torque values on a second axis, and vibration amplitude values on a third axis, vibration frequency values on a fourth axis, and specifies diagnostic conditions for table entries. Some embodiments include look up tables with greater or fewer numbers of axes, for example, a single axis of differences between the first torque values and the second torque values rather than separate axes for first net torque values and second net torque values, or tables which omit one or more of the foregoing four axes or include additional axes with other data values. From operation  350  process  300  proceeds to operation  360  where process  300  returns operation  310 , returns to another operation of process  300 , or ends. Operation  360  may also call for another process to be performed. 
         [0027]    With reference to  FIG. 4  there is illustrated a flowchart according to an exemplary diagnostic process  400  which includes multiple operations that can be performed by a controller such as ECM  130  described above or one or more additional or alternate controllers. 
         [0028]    Operation  410  operates a hybrid powertrain system including one or more engine(s) and one or more motor/generator(s). The hybrid powertrain system may be system  100  described above or another hybrid powertrain system. The hybrid powertrain system may have a series configuration, a parallel configuration or a series/parallel configuration, and may operate in a series mode of operation, a parallel mode of operation, a series/parallel mode of operation or may vary among such modes of operation. From operation  410  process  400  proceeds to operation  420 . 
         [0029]    Operation  420  senses one or more characteristics of a motor/generator of the hybrid powertrain system. Some embodiments sense electrical characteristic(s) of the generator, for example, one or more of the electrical characteristics described above or other electrical characteristics. Some embodiments sense acceleration characteristics of the motor/generator, for example, one or more of the acceleration characteristics described above or other acceleration characteristics. From operation  420  process  400  proceeds to operation  430 . 
         [0030]    Operation  430  uses one or more sensed characteristics of the motor/generator to determine a first net torque of the engine of the hybrid powertrain system. Some embodiments determine the first net torque based upon an electrical characteristic of the motor/generator based upon one or more of the relationships described above or other relationships an electrical characteristic of the motor/generator and the engine torque. Some embodiments determine the first net torque based upon an acceleration characteristic of the motor/generator based upon one or more of the relationships described above or other relationships an acceleration characteristic of the motor/generator and the engine torque. Some embodiments determine the first net torque based upon another characteristic of the motor/generator. From operation  430  process  400  proceeds to operation  440 . 
         [0031]    Operation  440  uses a model to determine a second net torque of the engine of the hybrid powertrain system. Some embodiments determine gross torque based upon fueling information, and determine net torque by accounting for friction losses, pumping losses, cam losses, accessory losses and parasitics. Some embodiments utilize models which account for additional or alternate factors, for example, turbocharger information, engine speed information and others. In the illustrated example operation  440  is performed after operation  430 . In other embodiments operation  440  is performed before operation  420 , in parallel with operation  420 , before operation  430 , in parallel with operation  430 . From operation  440  process  400  proceeds to operation  450 . 
         [0032]    Operation  450  senses a vibration characteristic of the system. Some embodiments use one or more accelerometer(s) coupled with the engine to measure vibration, amplitude, frequency, or amplitude and frequency. In some embodiments one or more accelerometers are coupled with other system components or at other locations, for example, a motor/generator, a vehicle frame, transmission, mount, support or other structure. In the illustrated embodiment operation  450  is performed after operation  440 . In other embodiments operation  450  is performed before operation  420 , in parallel with operation  420 , before operation  430 , in parallel with operation  440 , before operation  440  or in parallel with operation  440 . From operation  450  process  400  proceeds to operation  460 . 
         [0033]    Operation  460  diagnoses the system based upon the first net torque, the second net torque and the vibration characteristic. Some embodiments include a four dimensional look up table which includes first net torque values on a first axis, second net torque values on a second axis, and vibration amplitude values on a third axis, vibration frequency values on a fourth axis, and specifies diagnostic conditions for table entries. Some embodiments include look up tables with greater or fewer numbers of axes, for example, a single axis of differences between the first torque values and the second torque values rather than separate axes for first net torque values and second net torque values, or tables which omit one or more of the foregoing four axes or include additional axes with other data values. From operation  460  process  400  proceeds to operation  470  where process  400  returns operation  410 , returns to another operation of process  400 , or ends. Operation  470  may also call for another process to be performed. 
         [0034]    The exemplary embodiments of the invention illustrated and described in detail in the figures and foregoing description are illustrative and not limiting or restrictive. Only the presently preferred exemplary embodiments have been shown and described and all changes and modifications that come within the scope of the invention are to be protected. It should be understood that various features and aspects of the embodiments described above may not be necessary and embodiments lacking the same are also protected. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.