Patent ID: 6161522
Filing Date: 2000-12-19
Classification: E02F,F02D,F04B

Abstract:
A construction machine having a working portion, comprising:a hydraulic cylinder for operating the working portion of the construction machine;a variable capacity pump for providing pressurized hydraulic fluid to the hydraulic cylinder via a discharge passageway, wherein the hydraulic cylinder is actuated when pressurized hydraulic fluid is supplied thereto, the variable capacity pump having a swash plate;an engine for providing power to the construction machine, the engine connected to the variable capacity pump for driving the variable capacity pump;fuel injection means for injecting fuel into the engine via a fuel passageway;relief control means for regulating a pressure of hydraulic fluid in the discharge passageway of the variable capacity pump;pump output control means for regulating an output flow rate of hydraulic fluid from the variable capacity pump;control means for controlling an output flow rate of the fuel injection means, for controlling the relief control means, and for controlling the pump output control means,wherein the control means controls the fuel injection means, the relief control means, and the pump output control means to produce a first product of the pressure of hydraulic fluid in the discharge passageway of the variable capacity pump and the output flow rate of hydraulic fluid from the variable capacity pump, the first product being substantially a predetermined value when the construction machine is in a normal mode of operation;wherein the control means controls the fuel injection means, the relief control means, and the pump output control means to produce a second product of the pressure of hydraulic fluid in the discharge passageway of the variable capacity pump and the output flow rate of hydraulic fluid from the variable capacity pump, the second product being greater than the first product when the construction machine is in an active mode of operation in which the construction machine requires a greater working force and a greater working speed than that required during the normal mode of operation;wherein the control means controls the fuel injection means, the relief control means, and the pump output control means to produce, for a predetermined period of time, a third product of the pressure of hydraulic fluid in the discharge passageway of the variable capacity pump and the output flow rate of hydraulic fluid from the variable capacity pump, the third product being greater than the second product when the construction machine is in a power active mode of operation in which the construction machine requires, for the predetermined period of time, a greater working force and a greater working speed than that required during the active mode of operation;wherein the control means controls the fuel injection means, the relief control means, and the pump output control means to produce the second product of the pressure of hydraulic fluid in the discharge passageway of the variable capacity pump and the output flow rate of hydraulic fluid form the variable capacity pump after the predetermined period of time has passed.