1. Research and development of methods and means
to increase energy efficiency
of hydraulic drive installations on mobile machinery
Reducing energy losses by using “LS” pumps
Increasing efficiency of Fluid Power systems by means of digital hydraulics
Kinetic and/or potential energy recovery and reuse
Financial support and Partners are needed
Osijek,

2. Reducing energy losses by using “LS” pumps
Constant Flow Pump
Qs-load flow;
Qmax-pump flow;
ps-load pressure;
pmax-safety valve
pressure
Pu-power used-generates mechanical work: Pu=Qs·ps
Pl-power lost-causes heating of the working fluid
Pl=Pl1+Pl2
Pl1-power lost through throttle valve: Pl1=Qs(pmax-ps)
Pl2-power lost through safety valve: Pl2=(Qmax-Qs)pmax
Significant power loss when pressure and flow required by pump are low.

3. Reducing energy losses by using “LS” pumps
Constant Flow and Load Sensing Pump
Qs-load flow;
Qmax-pump flow;
ps-load pressure;
p-pressure drop in
the throttle valve
Pu-power used- generates mechanical work: Pu=Qs·ps
Pl-power lost- causes heating of the working fluid
Pl=Pl1+Pl2
Pl1-power lost through throttle valve: Pl1=Qs·p
Pl2-power lost through flow control valve: Pl2=(Qmax-Q)(ps+p)
Good power balance.
Load flow is constant regardless of load pressure variations.

4. Reducing energy losses by using “LS” pumps
Variable Flow and Load Sensing Pump
Qs-load flow;
ps-load pressure;
p-pressure drop in
the throttle valve
Pu-power used- generates mechanical work: Pu=Qs·ps
Pl-power lost- causes heating of the working fluid:
Pl=Qs·p
Very good power balance.
Load flow is constant regardless of load pressure variations and/or drive speed variation (heat engine).

5. Digital pumping systems
Increasing efficiency of Fluid Power systems by means of digital hydraulics
Digital pumping systems
Digital pumping system
in parallel connection
b) Digital pumps with
each piston controlled
For instance: √ three non-adjustable pumps driven by a single shaft
√ directional control valves in parallel controlled by a binary algorithm
For instance: √ pump with three pistons arranged in line
√ each piston may pump into the system or may run idle
Advantages of digital pumps:
- They can be built out of simple parts; - They have fast operation; - They can drive several actuation parts (joint/shared use); - Energy savings, especially during joint use and under partial load.

6. Kinetic and/or potential energy recovery and reuse
Kinetic energy recovery
Conceptual model of a kinetic energy recovery system
The hydraulic recovery system is conceived like a mechatronics system, usable for medium and heavy motor vehicles. Implementation of the kinetic energy recovery hydraulic system on a motor vehicle transforms it into a hybrid vehicle and leads to decreasing the fuel consumption and reducing the gas emissions. In this manner, the negative impact on the environment and on the fossil energy resources will be reduced.

7. Kinetic and/or potential energy recovery and reuse
→ Fuel reduction and CO2 savings
→ Operator does not feel any differences
→ About 54 % of the potential energy can be regenerated

8. PhD.Eng. Ioan LEPĂDATU lepadatu.ihp@fluidas.ro
Thank you!
CONTACT PERSON:
PhD.Eng. Ioan LEPĂDATU