Design Challenge - June 2014

Recovery of Heat and Kinetic Energy - Alberto Seco

The ADT HY2 hydraulic hybrid energy recovery system is based around the 50+Active suspension system (iVT June 2013), which acts as a flexible link between the front and rear frames, improving stability and minimizing rollover of the cab.

In contrast to current ADTs, hydropneumatic suspension is not only limited to the wheels, but is extended to the frame using two large cast upper and lower ‘H’ arms controlled by a pair of suspension cylinders and hydraulic accumulators. These dampen energy from bumps to produce a smooth ride for maximum operator comfort. Position sensors in the frame continually measure and adapt to uneven terrain, while the lateral sensors measure any roll and constantly adjust cylinders to accommodate for this.

The increase of pressure in the accumulators converts kinetic energy into hydraulic energy that can drive an axial piston pump coupled to the gearbox to provide an additional source of power. A valve control block positioned between the accumulators and this pump controls the filling and discharge cycle, protecting the system from excessive pressure.

An ECU monitors the engine performance for optimal operation, so less fuel is consumed without sacrificing power requirements. When more power is needed, the ECU therefore manages the stored energy in the accumulators to provide an additional source of power and to help reduce fuel consumption. The Poclain 400 HY2 (iVT Sept 2010) energy recovery system is based on the recovery of heat from the hydraulic oil tank.

In a conventional excavator, the hydraulic oil must be refrigerated, but because electric-drive systems provide some of the best solutions for the recovery and storage of energy, the HY2 concept excavator has been equipped with a series hybrid system that can transfer this thermal energy to the hydraulic pumps when needed.

Semiconductors and thermoelectric materials extract the heat from the hydraulic oil tank, and send it to a supercapacitor, while an electric motor positioned between the engine and the hydraulic pumps supplies additional power to reach an overall power rating of 500bhp.

The thermal energy focused on the hydraulic oil tank is therefore converted into additional hydraulic energy to help drive the swing hydraulic motor, the equipment hydraulic cylinders or the track- drive hydraulic motors. Because the generator uses electricity from the capacitor to provide power-up engine assistance, fuel consumption is also reduced.

A further advantage of replacing the hydraulic fluid cooler (which usually involves a wasting of energy) is the reduction in size of the hydraulic oil tank, leading to less oil, reduced maintenance costs and an improved ecological approach.

More images from Alberto Seco

* Click on a thumbnail below to view a larger image.


Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco
Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco Alberto Seco



Alberto has been involved in design projects from cell phones to heavy equipment. After a spell at an Italian design consultancy and as an industrial designer, he now works in the auto sector.