The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 22, 2017
Filed:
Sep. 10, 2015
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A construction machine includes an engine, a load estimation unit that estimates a pump power absorption, a regeneration/powering power demand calculation unit that calculates a regeneration/powering power demand according to a state of charge in an electrical storage device, an engine power demand calculation unit that calculates an engine power demand based on the power absorption and regeneration/powering power demand, and a motor generator control unit that performs rotational speed control or torque control. The control unit includes a control switching unit that switches the rotational speed and the torque control according to the engine power demand and the rotational speed of the engine. The control switching unit switches from the torque control to the rotational speed control when during performance of the torque control, the engine power demand increases and the rotational speed of the engine becomes lower than a predetermined rotational speed.