Towards more efficient mobile Hydraulic Systems

Towards more efficient mobile Hydraulic Systems

Petter KrusDivision of Fluid and Mechatronic SystemsDepartment of Management and Engineering

2

Linköping University• Sweden 9.5 million people

• Linköping Municipality 140 000 people

• Linköping University 27 000 students

Linköping, Sweden

Linköping Malmen

Birthplace of Swedish Aviation 1911

Carl Cederström 1912

Petter Krus

2018-12-07Linköpings universitet

Sid 5

Mechatronics

Aircraft design

Design analysis and optimisation

Modelling and simulation

Aircraft Systems Fluid Power

Embedded systems

Flumes Research Areas

Systems Engineering

MechatronicSystems

Onboard systems

Subscale flight testing

Measurement and control systems

Hydraulic system and component design

Mobile systemsSensor systems

Noise and vibrations

Some Industrial Partners andApplications

2018-12-07 Sid 6

Construction MachinesVolvo CE

AircaftSaab AB

Rock drillsEpiroc(formerly Atlas Copco)

HOPSAN-NG (Next Generation)

• Bidirectional delay-lines

• Modelica support is under development

• Genuine team work

• Freeware that can be downloaded from http://www.iei.liu.se/flumes/system-simulation/hopsanng

Petter Krus

Friday afternoon workshop= “happy hour”

Open Centre SystemPetter Krus

Load Sensing System Petter Krus

Negative Load Sensing System

Pump is regulated to keep the flow in the opencentre constant

Petter Krus

Related Systems• Open flow control

– Feed forward control of pump displacement from sum of flow demands.

Petter Krus

Energy Efficiency

Pressure

Pressure Flow

FlowLoad Sensing

Open Centre

Petter Krus

Energy Efficiency

Pressure

Pressure Flow

FlowLoad Sensing

Constant pressure

Petter Krus

General system configuration for a hydraulic transmission (motor or cylinder)

14

sp

vx

M

Lp

P

,P PTLT

,M MT

vx vx

Losses in combustion

engine

Losses in pumps and

motors

Throttling losses

Gravity losses,

active

Idling losses

Gravity losses,

passive

Petter Krus

Open centre system (motor or cylinder)

15

sp

vx

Lp

,P PTLT

,M MT

vx vx


engine

Losses in pumps and

motors

Throttling losses

Idling losses

Petter Krus

Pump controlled constant pressure system

16


engine

Losses in pumps and

motors

Throttling losses

Idling losses

sp

vx

Lp

P

,P PTLT

,M MT

vx

Petter Krus

Load sensing or open flow control (motor or cylinder)

17

sp

vx

Lp

P

,P PTLT

,M MT

vx


engine

Losses in pumps and

motors

Throttling losses

Idling losses

Petter Krus

vx

vx

Pump controlled motor (or cylinder)

18

spLp

P

,P PTLT

,M MT

vx


engine

Losses in pumps and

motors

Idling losses

Petter Krus

Secondary control (over-center controlled motor). Common rail. Energy recuperation

19


engine

Losses in pumps and

motors

Idling losses

sp

M

Lp

,P PTLT

,M MT

P

Petter Krus

Secondary control (over-center controlled motor). Common rail. Electric motor control.

20


engine

Losses in pumps and

motors

Idling losses

sp

M

Lp

,P PTLT

,M MT

P

M

Petter Krus

Fluid Power Systems for Working Machineryvariable area cylinders!

2018-12-07 21Kim Heybroek

Fuel efficiency (ton/liter)


Fluid Power Systems for Working Machinery


Cost/Complexity

Fue

l Eff

icie

ncy

Independent meter-in and meter-out

• Minimize pressure on the low pressure side can reduce lossesdepending on load cycles

• Flow can be drawn from tank (instead of pump) when lowering a load.

• Opening both sides to pressure give a high speed mode.

• Identical elements can be used. No tuning. Less articles in inventory.

2018-12-07 24Title/Lecturer

sp

vx

Rp

LF

sp

Ap Bp

Rp

LF

Four individual metering

• Allows for use of seat valves

• Four identical elements. Larger series of valves.

2018-12-07 25Petter Krus

spRp

ApBp

LF

2018-12-07 25

Force

Three chamber cylinder(or more)

• Can be used for ”digital hydraulics” or multi mode hydraulics. ”Variable area cylinder”.


Rp

ApBp

LFCp

sp

Force

0

0

0

2

4

C

B

A

A A

A A

A A

=

=

=




Rp

ApBp

LFCp

sp

Force

0

0

0

2

4

C

B

A

A A

A A

A A

=

=

=




Rp

ApBp

LF

Rp

Cp

Force

sp

0

0

0

2

4

C

B

A

A A

A A

A A

=

=

=

Electrified Hydraulics for Vehicles

29

Potential:

80% less energy consumption

Around 8% fuelsaving, overall.

The HILA TechnologyMagnus Landberg

▪ EXTENDED WORKING RANGE

- Long piston rods open up new areas and applications

for hydraulic cylinders for example in elevators in high

rises, additive manufacturing, AS/RS, Gantry robots,

CNC machines, etc.

▪ INCREASED CONTROL STABILITY

- Higher stiffness, higher natural frequency and higher

system pressure

▪ COMPACTNESS

– Much shorter and lighter cylinder and a higher

system pressure - > Significant reductions in weight

and volume, more cost-efficient and compact overall

system designs, especially reservoirs.

A hydraulic actuator invention that allows very long strokes!

HILATM

(HILA = Hydraulic Infinite Linear Actuator, see animation on Youtube: HILA - How it works)

▪ EXAMINED IN A BRAND

NEW DISSERTATION

▪ PROOF OF CONCEPT

- Successful tests with a vertical load (400 kg),

in FLUMES hydraulic lab at Linköping University,

sponsored by the Swedish Energy Agency.

▪ PATENTED TECHNOLOGY

https://www.youtube.com/watch?v=tVJkqC2w5ws&index=1&list=PLydomcmdKUnhVW8Ias9M9OQP8Gh9XgYWb

Linear Incremental Hydraulic Actuator

Martin Hochwallner

Characteristic: Long Stroke

• Incremental motion: No conceptual limit in stroke length

Martin Hochwallner

Characteristic: Hybrid System

3 (1) DoFs, temporarily coupled2 (1) continuous control inputs2 (0) discrete control inputs

Martin Hochwallner

Gait -- Smooth Motion

Martin Hochwallner

Gait -- Ballistic Gait

Martin Hochwallner

Gait -- Ballistic Gait

time in sec

Martin Hochwallner

Digitalization

• Whats new?

• Cost of anything electronic is going down, including sensors and communication.

• IoT, Big data allows for condition monitoring and prognostics on a new scale. Also to establish much more precise requirements for new designs.

• Safety regulations in Europe is requiring sensors for e.g. pressure and position the hence is ”free” for other functions thatnow can be implemented. E.g. crane tip control.

• 3D printing will allow for new more efficient geometries and for a different supply chain.

Petter Krus

Summary

Loadsensing

Individualmetering

Integratedcontrol drivelinework hydraulics

Electric pumps

Multi chambercylinders

Open flowcontrol

Petter Krus

Efficiency

Cost

Electric pump controlledcylinders

Conclusions: Is there a future for Fluid Power?

• Yes!

2018-12-07 44Title/Lecturer

Towards more efficient mobile Hydraulic Systems

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