Cranking-caused vibration suppressing apparatus and method for internal combustion engine

Abstract

At the time of (i.e., during) cranking of an internal combustion engine, an engine cranking-caused vibration suppressing apparatus and method controls the operation of an electric motor that cranks the internal combustion engine based on the rotational phase of the crankshaft detected by a crankshaft rotational phase detector so that the output torque of the motor fluctuates similarly to fluctuations in resistance torque against the cranking of the engine that the crankshaft presents in accordance with the rotational phase thereof. Thus, the apparatus and method are able to suppress vibrations during the cranking of the engine, leading to improvements in the riding comfort and the noise suppression of a vehicle.

1. A vibration suppressing apparatus for suppressing a vibration of an internal combustion engine caused by a cranking of the internal combustion engine performed by a motor, comprising:
 a rotational phase detector that detects a rotational phase of a crankshaft of the internal combustion engine; and  
 a controller that controls an operation of the motor based on the detected rotational phase of the crankshaft detected by the rotational phase detector so that an output torque of the motor fluctuates during the cranking similarly to a fluctuation in a resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft, the fluctuation in the resistance torque including at least a fluctuation in a resistance torque caused by compression of an intake air by the internal combustion engine, wherein the controller estimates the fluctuation in the resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft, and the controller adjusts the rotational phase of the crankshaft occuring at a beginning of the cranking to a predetermined phase.  
 
     
     
       2. The vibration suppressing apparatus according to  claim 1 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine inertia resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       3. The vibration suppressing apparatus according to  claim 2 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       4. The vibration suppressing apparatus according to  claim 1 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       5. The vibration suppressing apparatus according to  claim 1 , wherein the controller controls the operation of the motor so that a rotation angular acceleration of the crankshaft with respect to the rotational phase of the crankshaft follows a predetermined schedule. 
     
     
       6. A method for suppressing a vibration of an internal combustion engine caused by a cranking of the internal combustion engine performed by a motor, comprising:
 detecting a rotational phase of a crankshaft of the internal combustion engine;  
 controlling an operation of the motor, based on the detected rotational phase of the crankshaft, so that an output torque of the motor fluctuates during the cranking similarly to a fluctuation in a resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft, the fluctuation in the resistance torque including at least a fluctuation in a resistance torque caused by compression of an intake air by the internal combustion engine;  
 adjusting the rotational phase of the crankshaft occurring at a beginning of the cranking to a predetermined phase, wherein the fluctuation in the resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft is determined by an estimation.  
 
     
     
       7. The method according to  claim 6 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine inertia resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       8. The method according to  claim 7 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       9. The method according to  claim 6 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       10. The method according to  claim 6 , further comprising:
 detecting a rotation angular acceleration of the crankshaft with respect to the rotational phase of the crankshaft; and  
 controlling the operation of the motor so that the rotation angular acceleration follows a predetermined schedule.  
 
     
     
       11. A vibration suppressing apparatus for suppressing a vibration of an internal combustion engine caused by a cranking of the internal combustion engine performed by a motor, comprising:
   a rotational phase detector that detects a rotational phase of a crankshaft of the internal combustion engine; and        a controller that controls an operation of the motor based on the detected rotational phase of the crankshaft detected by the rotational phase detector so that an output torque of the motor fluctuates during the cranking similarly to a fluctuation in a resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft, the fluctuation in the resistance torque including at least a fluctuation in a resistance torque caused by compression of an intake air by the internal combustion engine, wherein the controller estimates the fluctuation in the resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft.     
     
     
       12. The vibration suppressing apparatus according to  claim 11 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine inertia resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       13. The vibration suppressing apparatus according to  claim 12 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       14. The vibration suppressing apparatus according to  claim 11 , wherein the fluctuation in the resistance torque compensated for by the controller further includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       15. The vibration suppressing apparatus according to  claim 11 , wherein the controller controls the operation of the motor so that a rotation angular acceleration of the crankshaft with respect to the rotational phase of the crankshaft follows a predetermined schedule. 
     
     
       16. A method for suppressing a vibration of an internal combustion engine caused by a cranking of the internal combustion engine performed by a motor, comprising:
   detecting a rotational phase of a crankshaft of the internal combustion engine;        controlling an operation of the motor, based on the detected rotational phase of the crankshaft, so that an output torque of the motor fluctuates during the cranking similarly to a fluctuation in a resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft, the fluctuation in the resistance torque including at least a fluctuation in a resistance torque caused by compression of an intake air by the internal combustion engine;        wherein the fluctuation in the resistance torque against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft is determined by an estimation.     
     
     
       17. The method according to  claim 16 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine inertia resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       18. The method according to  claim 17 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       19. The method according to  claim 16 , wherein the fluctuation in the resistance torque also includes a fluctuation in an internal combustion engine friction resistance torque exerted on the crankshaft against the cranking of the internal combustion engine that the crankshaft presents in accordance with the rotational phase of the crankshaft. 
     
     
       20. The method according to  claim 16 , further comprising:
   detecting a rotation angular acceleration of the crankshaft with respect to the rotational phase of the crankshaft; and        controlling the operation of the motor so that the rotation angular acceleration follows a predetermined schedule.