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Control system for hybrid construction machine

  • US 8,606,452 B2
  • Filed: 02/01/2011
  • Issued: 12/10/2013
  • Est. Priority Date: 02/12/2010
  • Status: Expired due to Fees
First Claim
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1. A control system for a hybrid construction machine, comprising:

  • a variable-capacity main pump;

    an engine that drives the main pump;

    an engine rotation speed controller that controls the rotation of the engine;

    a generator;

    a battery that stores power generated by the generator;

    a variable-capacity sub-pump connected to a discharge side of the main pump and adapted to assist the main pump;

    an assist control mechanism that controls the sub-pump to output a commanded assist output;

    a storage that stores a coefficient table for an assist correction coefficient used to reduce an assist output of the sub-pump by controlling the assist control mechanism when the storage amount of the battery is below a threshold value, a coefficient table for an engine rotation speed correction coefficient used to increase the rotation speed of the engine when the storage amount of the battery is below the threshold value, and the threshold value for the storage amount of the battery; and

    a controller that determines whether or not the storage amount of the battery is below the threshold value, and when the storage amount of the battery is below the threshold value, reduces the assist output of the sub-pump by controlling the assist control mechanism based on the assist correction coefficient, increases the discharge amount of the main pump by controlling the engine rotation speed controller based on the engine rotation speed correction coefficient and increasing the rotation speed of the engine, and increases an output of the main pump by increasing the rotation speed of the engine by as much as a reduction in the assist output of the sub-pump.

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