29-04-2017, 03:19 PM
Hybrid hydraulic vehicles, or HHVs, use a pressurized fluid energy source, along with a conventional internal combustion engine (ICE), for better fuel economy and harmful emissions reductions. They capture and reuse 70% -80% of the braking / deceleration energy of the vehicle compared to 25% for electric hybrids. [Citation needed] For trucks and buses, this can also be less expensive than electrical systems, due to the price of the batteries required for later. Hydraulic hybrid vehicle systems can also weigh less than electric systems because of the high weight of the batteries. This can lead to a lower impact on payload capacity, especially for heavy truck classes.
Hybrid vehicle hydraulics consists of four main components: working fluid, tank, pump / motor (in parallel hybrid system) or engines and pumps on the wheel (in series hybrid system) and the accumulator. In some systems, a hydraulic transformer is also installed to convert the output flow to any pressure with a very low power loss. In an electric hybrid system, energy is stored in the battery and delivered to the electric motor to power the vehicle. During braking, the kinetic energy of the vehicle is used to charge the battery through regenerative braking. In the hydraulic hybrid system, the pump / motor draws the kinetic energy during braking to pump the working fluid from the reservoir to the accumulator. Therefore, the working fluid is pressurized, which leads to energy storage. When the vehicle accelerates, this pressurized working fluid provides power to the pump / engine to power the vehicle. For a parallel hybrid system, fuel efficiency gains and emission reductions result from reduced mechanical load on the internal combustion engine due to the torque provided by the hybrid system.
In some cases, hybrid hydraulic systems can be more cost effective than hybrid electric systems because no complicated or expensive materials (such as those required for batteries) are used. However, in most designs, the accumulator pressure tanks are made of carbon fiber, which makes pressure tanks expensive, but the price of carbon fiber is expected to drop and the Economies of scale can reduce the cost of manufacturing tanks.
Hydraulic hybrids recover or harvest the vehicle's kinetic energy during braking and deceleration significantly more efficiently than electric systems; Hydraulic hybrids can recover up to 75% of the kinetic energy of the vehicle compared to 25% for electric hybrids.
Reduced cost, complexity and weight for additional power take-off devices such as water pumps, hydraulic lifts and winches.
Technical challenges with hydraulic hybrid vehicles include noise, size and complexity. Technical advances such as large-diameter, flat-format (LDFF) hydraulic motors, which produce very high torque in the limited transmission space, allow heavy vehicles such as garbage trucks and city buses to be equipped with hybrid systems Hydraulics. Sophisticated control software results in hydraulic hybrid vehicles that are safe, manageable, reliable and efficient.
Hybrid vehicle hydraulics consists of four main components: working fluid, tank, pump / motor (in parallel hybrid system) or engines and pumps on the wheel (in series hybrid system) and the accumulator. In some systems, a hydraulic transformer is also installed to convert the output flow to any pressure with a very low power loss. In an electric hybrid system, energy is stored in the battery and delivered to the electric motor to power the vehicle. During braking, the kinetic energy of the vehicle is used to charge the battery through regenerative braking. In the hydraulic hybrid system, the pump / motor draws the kinetic energy during braking to pump the working fluid from the reservoir to the accumulator. Therefore, the working fluid is pressurized, which leads to energy storage. When the vehicle accelerates, this pressurized working fluid provides power to the pump / engine to power the vehicle. For a parallel hybrid system, fuel efficiency gains and emission reductions result from reduced mechanical load on the internal combustion engine due to the torque provided by the hybrid system.
In some cases, hybrid hydraulic systems can be more cost effective than hybrid electric systems because no complicated or expensive materials (such as those required for batteries) are used. However, in most designs, the accumulator pressure tanks are made of carbon fiber, which makes pressure tanks expensive, but the price of carbon fiber is expected to drop and the Economies of scale can reduce the cost of manufacturing tanks.
Hydraulic hybrids recover or harvest the vehicle's kinetic energy during braking and deceleration significantly more efficiently than electric systems; Hydraulic hybrids can recover up to 75% of the kinetic energy of the vehicle compared to 25% for electric hybrids.
Reduced cost, complexity and weight for additional power take-off devices such as water pumps, hydraulic lifts and winches.
Technical challenges with hydraulic hybrid vehicles include noise, size and complexity. Technical advances such as large-diameter, flat-format (LDFF) hydraulic motors, which produce very high torque in the limited transmission space, allow heavy vehicles such as garbage trucks and city buses to be equipped with hybrid systems Hydraulics. Sophisticated control software results in hydraulic hybrid vehicles that are safe, manageable, reliable and efficient.