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.

Description

INCORPORATION BY REFERENCE[0001]The disclosure of Japanese Patent Application No. 2000-358905 filed on Nov. 27, 2000, including the specification, drawings and abstract is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of Invention[0003]The invention relates to apparatus and methods for suppressing vibrations of an internal combustion engine caused by the cranking of the engine.[0004]2. Description of Related Art[0005]A reciprocating piston engine, that is, a type of internal combustion engine, is started by a cranking operation of turning a crankshaft of the engine via an electric motor. Conventionally, substantially no technical attention has been given to vibrations caused at the time of the cranking of the engine, more precisely, during the cranking thereof. With regard to the vibrations at the time of a start of an engine, Japanese Patent Application Laid-Open No. 10-212983 describes an arrangement in which an engine is cranked by a f...

AI Technical Summary

Benefits of technology

[0008]Accordingly, it is one object of the invention to provide a cranking-caused vibration suppressing apparatus and method for an internal combustion engine that copes with the problem of vibrations occurring during the cranking of the engine, which is expected to greatly affect the riding comfort and the noise suppression of a vehicle in terms of timing and rate of occurrence of the vibrations.

[0011]In the vibration suppressing apparatus and method described above, the operation of the motor is controlled on the basis of the detected crankshaft rotational phase so that the output torque of the motor fluctuates similarly to a fluctuation in the resistance torque against the cranking of the engine presented by the crankshaft in accordance with the rotational phase thereof, the fluctuation in the resistance torque including at least the fluctuation in the resistance torque caused by intake air compression. Therefore, the motor produces an output torque corresponding to fluctuations in the resistance torque occurring on the crankshaft of the internal combustion engine. That is, the motor produces great output torque when the resistance torque is great, and produces small output torque when the resistance torque is small. As a result, vibrations of the engine are suppressed at the time of the cranking of the engine. Hence, the invention improves the riding comfort and the noise suppression during the engine cranking in a vehicle equipped with the above-described engine.

Problems solved by technology

That is, the motor produces great output torque when the resistance torque is great, and produces small output torque when the resistance torque is small.

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