Patent ID: 8739906
Filing Date: 2014-06-03
Classification: B60K,B60W,E02F,F02D,Y02T

Abstract:
1. A hybrid-type construction machine comprising: a controller configured to control a revolution speed of an engine; a hydraulic pump configured to be driven by the engine; a motor generator configured to assist the engine; a hydraulic circuit configured to supply an operating oil discharged from the hydraulic pump to a hydraulic load; a first pressure sensor configured to detect a pressure of the operating oil discharged from the hydraulic pump; a control valve provided in the hydraulic circuit and configured to control a flow of the operating oil into the hydraulic load; a negative control metering valve provided between the control valve and a tank; and a second pressure sensor provided between the control valve and the negative control metering valve and configured to detect negative control pressure, wherein the controller compares a first discharge quantity of the hydraulic pump acquired from a detection value of the first pressure sensor with a second discharge quantity of the hydraulic pump acquired from a detection value of the second pressure sensor, and wherein, when the controller determines that the hydraulic circuit is in an excessive output state, the controller controls the revolution speed of the engine so as to be lower than an ordinary revolution speed of the engine while controlling the motor generator to generate electricity depending on a result of the comparison between the first discharge quantity of the hydraulic pump with the second discharge quantity of the hydraulic pump.