With the development of energy storage technology, as an important way to improve the energy efficiency of hydraulic excavator, energy recovery has become the key direction of energy-saving development of hydraulic excavator. In the typical working cycle of excavator, the rotary motion of upper platform occupies a large proportion both in time and energy consumption. Therefore, it is of great significance to study the recovery and reuse of rotary energy of hydraulic excavator.
At present, there are three common ways of energy recovery: mechanical, electrical and hydraulic. Compared with the other two ways, hydraulic energy recovery technology is mature, low cost and high energy conversion efficiency. Traditional hydraulic excavators rely on the continuous high-pressure oil at the inlet of the rotary motor to accelerate the rotary motor during the rotary starting, and the continuous high-pressure oil established by the relief valve at the oil return port realizes the rotary braking during the braking, and the rotary motor starts and brakes frequently. This frequent short-term high-pressure working system matches the characteristics of high power density of the accumulator. Therefore, in recent years, people pay more attention to the energy recovery method of using accumulator as energy storage element to recover the rotary energy of hydraulic excavator. However, the above-mentioned energy recovery systems only focus on recovering the rotational kinetic energy of the upper platform during the rotary braking, and ignore the energy waste caused by the overflow of the rotary motor during the rotary starting, which hinders the further improvement of the energy utilization rate.
