10-04-2017, 07:23 PM
hydraulic hybrid system for four wheeler
Hydraulic hybrid vehicles, or HHVs use a pressurized fluid power source, along with a conventional internal combustion engine (ICE), to achieve better fuel economy. They capture and reuse 70%-80% of the vehicle's braking/decelerating energy[1] compared to 25% for electric hybrids.[citation needed] For trucks and buses, this can also be less expensive than electric systems, due to the price of batteries required for the latter.
Hydraulic hybrid vehicle systems consists of four main components: the working fluid, reservoir, pump/motor (in parallel hybrid system) or in-wheel motors and pumps (in series hybrid system), and accumulator. In some systems, a hydraulic transformer is also installed for converting output flow at any pressure with a very low power loss.[2] In electric hybrid system, energy is stored in the battery and is delivered to the electric motor to power the vehicle. During braking the kinetic energy of the vehicle is used to charge the battery through the regenerative braking. In hydraulic hybrid system, the pump/motor extracts the kinetic energy during braking to pump the working fluid from the reservoir to the accumulator. Working fluid is thus pressurized. When the vehicle accelerates, this pressurized working fluid provides energy to the pump/motor to power the vehicle.