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AssigneeHitachi Construction Machinery Co., Ltd.
InventorsEiki Izumi, Hiroshi Watanabe, Yukio Aoyagi, Kazuo Honma, Kichio Nakajima
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A control method of a system for generating hydraulic power, the system including an internal combustion engine controlled by fuel injection from a fuel injection pump, and a plurality of hydraulic pumps of the variable displacement type. An engine speed deviation is obtained by calculating a difference between a target engine speed set by a manipulated variable of an accelerator for the internal combustion engine and an output engine speed of the engine. The engine speed deviation is converted into a pump control coefficient which is in a functional relation with this deviation. A calculation is performed with the converted value and an externally manipulated variable for inclination of a swash plate of the hydraulic pump, and the calculated value is supplied to a regulator of the hydraulic pump as a target value for inclination of the swash plate thereof to thereby control the inclination angle of the swash plate of the hydraulic pump. At the same time, the engine speed deviation is converted into a rack displacement target value which is a functional relation with this deviation, and the rack displacement of the fuel injection pump is adjusted by the converted value to thereby control the amount of fuel injection.
A method of controlling a system for generating hydraulic power, the system including an internal combustion engine controlled by fuel injection by a fuel injection pump, and a plurality of hydraulic pumps of the variable displacement type driven by the internal combustion engine, the method comprising the steps of calculating a difference between a target engine speed set by a manipulated variable of an accelerator for the internal combustion engine and an output engine speed to obtain an engine speed deviation;
A method of controlling a system for generating hydraulic power, the system including an internal combustion engine, and at least one hydraulic pump of the variable displacement type driven thereby, the method comprising the steps of obtaining an engine speed deviation representing a difference between a target engine speed and an output engine speed is obtained based on a target engine speed signal produced by operation of an accelerator lever and an output engine speed signal detected by a sensor, converting said engine speed deviation into a corresponding pump control coefficient based on the pump control coefficient previously set as a function of the difference between the target engine speed and the output engine speed, performing a calculation with said pump control coefficient and a target speed based on a target speed signal produced by operation of an operation lever to obtain a pump delivery to thereby control the hydraulic pump in accordance with the target pump delivery signal calculating an increment of said engine speed deviation representing a difference between said target engine speed and said output engine speed, calculating an increment of said output engine speed, passing judgement as to whether or not the positive and negative signs of the two increments are alike, and, when the signs are alike, using a pump control coefficient having a value corresponding to the pump control coefficient immediately before the signs of the two increments become alike as said pump control coefficient of the two increments to perform the calculation with said target speed.
A method of controlling a system for generating hydraulic power, the system including an internal combustion engine, and at least one hydraulic pump of the variable displacement type driven thereby, the method comprising the steps of obtaining an engine speed deviation representing a difference between a target engine speed and an output engine speed based on a target engine speed signal produced by operation of an accelerator lever and an output engine speed signal detected by a sensor, converting said engine speed deviation into a corresponding pump control coefficient based on the pump control coefficient previously set as a function of the difference between the target engine speed and the output engine speed, performing a calculation with said pump control coefficient and a target speed based on a target speed signal produced by operation of an operation lever to obtain a target pump delivery to thereby control the hydraulic pump in accordance with the target pump delivery signal, detecting a change in said target engine speed, and maintaining, when said target engine speed undergoes a change, said target pump deliver for a predetermined time at the target pump delivery immediately before the target engine speed undergoes the change.
Dependencies are inferred from the claim text.