Efficiency improvement and evaluation of electric hydraulic excavator with speed and displacement variable pump

Energy efficiency analysis of integrated drive and energy recuperation system for hydraulic excavator boom

Facing severe environmental problems, to improve the efficiency of the hydraulic construction machinery is in great demand The potential energy when the boom is lowering is dissipated as heat in hydraulic system It is urgent to improve the maximum use of regeneration energy to reduce the fuel consumption This paper first analyzes the proportion of regeneration energy for each actuator and studies the special working style of the boom energy regeneration system (ERS) in a 20-t HE Then, types of the ERS are discussed The research and development of the electric ERS technology and the hydraulic ERS technology based on construction machinery are reviewed At last, the paper puts forwards the challenges and the future development of ERSs

Review of boom potential energy regeneration technology for hydraulic construction machinery

Review of hybrid electric systems for construction machinery

A review of developments in energy storage systems for hybrid excavators

New compound energy regeneration system and control strategy for hybrid hydraulic excavators

Performance analysis of an automatic idle speed control system with a hydraulic accumulator for pure electric construction machinery

The invention discloses an oil electro-hydraulic hybrid driving system for a hydraulic digging machine. The oil electro-hydraulic hybrid driving system comprises a hybrid driving system, a movable arm electro-hydraulic control unit, a rotary table electro-hydraulic control unit, a hydraulic energy accumulator, a one-way valve, a pilot handle, a storage battery, a metering pump/motor, a second motor/electric generator and the like. The oil electro-hydraulic hybrid driving system adopts the storage battery and the hydraulic energy accumulator as composite energy storage units, the hydraulic energy accumulator is utilized for providing or absorbing instant high power, and the storage battery is utilized for guaranteeing energy density. A rotary table adopts the hybrid driving of the motor/electric generator and the hydraulic motor, the instant high power during the starting and braking of the rotary table is guaranteed by utilizing the hydraulic energy accumulator, and good rotational speed control characteristic of the rotary table is guaranteed through the motor/electric generator; the pressure control on the rodless cavity of a driving oil cylinder is adjusted through the active control on the pressure of the hydraulic energy accumulator, movable arm gravitational potential energy is distributed on a balancing oil cylinder as much as possible, and then the energy recovery efficiency is improved; meanwhile, a speed control characteristic is guaranteed through the driving oil cylinder.

Oil electro-hydraulic hybrid driving system for hydraulic digging machine

The utility model provides an automatic idling system of an electro-hydraulic mixing driving engineering machine The automatic idling system works in the following steps that 1) idling time, pilot pressure threshold, hydraulic accumulator pressure determining threshold and the like are set; 2) whether a pilot handle pressure signal enters an automatic idling mode or not is detected; 3) when the time that the system stops working exceeds the idling time, the automatic idling system goes to the next step; 4)when difference of the pressure of a hydraulic accumulator to the maximum pressure of load is small than the negative pressure determining threshold, , the automatic idling system goes to the step 5), otherwise goes to the step 6); 5) an electromotor works in an electric-driven mode, and a quantity pump/a motor works in a pump mode; 6) the electromotor works in the electric-driven mode, and the hydraulic oil of the quantity pump/the motor are unloaded via multiple valves; and 7) the automatic idling system enters the working mode to detect the pressure at an outlet of the quantity pump/the motor According to the utility model, a problem can be solved that a hydraulic pump outlet is hard to quickly establish to overcome the pressure required by the load when the automatic idling speed is canceled; and hydraulic energy recycled via energy can be changed into electric energy in the automatic idling speed mode

Huang Weiping

Papers

New compound energy regeneration system and control strategy for hybrid hydraulic excavators

Review of boom potential energy regeneration technology for hydraulic construction machinery

Performance analysis of an automatic idle speed control system with a hydraulic accumulator for pure electric construction machinery

Oil electro-hydraulic hybrid driving system for hydraulic digging machine

Automatic idling system of electro-hydraulic mixing driving engineering machine