To overcome the drawbacks of a sequential design approach, this paper shows the precise combination of technology, topology, size and control for the power steering system used in a heavy-duty vehicle. Modeling of six possible topologies and optimal sizing of components, as the gear ratio between combustion engine and power steering pump, are shown. Next, a sensitivity analysis is done for control parameters and a view is presented on a suitable topology for a power steering system used in a heavy-duty long-haul vehicle.

1. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design of Power Steering Systems for
Heavy-Duty Long-Haul Vehicles
E. Silvas1, E. Backx1, T. Hofman1, H. Voets2 and M.
Steinbuch1
1Control Systems Technology Group
Dept. of Mechanical Eng., Eindhoven University of Technology, The Netherlands
2DAF Trucks NV, Eindhoven, The Netherlands
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

2. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Auxiliary Units
"Belt driven auxiliary units can
consume up to 4% of the total power
for a long haul heavy duty truck...
Power Steering Pump
Air Brake Compressor
Air Cond. Compressor...
Silvas et al. (2013). Modeling for control and optimal design of a
power steering pump and an air conditioning compressor used in
heavy duty trucks. In the 9th IEEE VPPC Conf., pp. 218-223, 2013
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

3. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Auxiliary Units
Belt driven auxiliary units can
consume up to 4% of the total power
for a long haul heavy duty truck...
Power Steering Pump
Air Brake Compressor
Air Cond. Compressor...
Silvas et al. (2013). Modeling for control and optimal design of a
power steering pump and an air conditioning compressor used in
heavy duty trucks. In the 9th IEEE VPPC Conf., pp. 218-223, 2013
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

4. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Auxiliary Units
Belt driven auxiliary units can
consume up to 4% of the total power
for a long haul heavy duty truck...
Power Steering Pump
Air Brake Compressor
Air Cond. Compressor...
Silvas et al. (2013). Modeling for control and optimal design of a
power steering pump and an air conditioning compressor used in
heavy duty trucks. In the 9th IEEE VPPC Conf., pp. 218-223, 2013
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

5. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Auxiliary Units
Belt driven auxiliary units can
consume up to 4% of the total power
for a long haul heavy duty truck...
Power Steering Pump
Air Brake Compressor
Air Cond. Compressor...
Silvas et al. (2013). Modeling for control and optimal design of a
power steering pump and an air conditioning compressor used in
heavy duty trucks. In the 9th IEEE VPPC Conf., pp. 218-223, 2013
Engine Cooling Fan
Water Pump
Air Brake
Compressor
Air Brake
Compressor
Steering Pump
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

6. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Auxiliary Units
Belt driven auxiliary units can
consume up to 4% of the total power
for a long haul heavy duty truck...
Power Steering Pump
Air Brake Compressor
Air Cond. Compressor...
Silvas et al. (2013). Modeling for control and optimal design of a
power steering pump and an air conditioning compressor used in
heavy duty trucks. In the 9th IEEE VPPC Conf., pp. 218-223, 2013
Starter Motor
Air Conditioning
Compressor
Fuel Pump
Alternator
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

7. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Losses of belt driven auxiliary units
Output is dictated by engine
speed
Limited controllability
Improvement Potential
Pure electric driving
Elimination of idling losses
Matching auxiliaries operation to
driver demand
More efficient engine operation
Different topology options
Engine Transmission
Final Drive
+ Wheels
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

8. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Losses of belt driven auxiliary units
Output is dictated by engine
speed
Limited controllability
Improvement Potential
Pure electric driving
Elimination of idling losses
Matching auxiliaries operation to
driver demand
More efficient engine operation
Different topology options
Engine Transmission
Final Drive
+ Wheels
Auxiliary
Units
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

9. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Losses of belt driven auxiliary units
Output is dictated by engine
speed
Limited controllability
Improvement Potential
Pure electric driving
Elimination of idling losses
Matching auxiliaries operation to
driver demand
More efficient engine operation
Different topology options
Engine Transmission
Final Drive
+ Wheels
Auxiliary
Units
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

10. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Motivation
Losses of belt driven auxiliary units
Output is dictated by engine
speed
Limited controllability
Improvement Potential
Pure electric driving
Elimination of idling losses
Matching auxiliaries operation to
driver demand
More efficient engine operation
Different topology options
Engine Transmission
Electric
Machine
Battery
Final Drive
+ Wheels
Auxiliary
Units
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

11. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Project Goal and Outline
Project Goal: Steering System Design
Optimal design of a steering system considering different
topologies, component sizes and control.
Outline
Alternative Steering System Topologies
Bi-level Optimization Problem
Optimal Design Results
Conclusions
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

12. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Project Goal and Outline
Project Goal: Steering System Design
Optimal design of a steering system considering different
topologies, component sizes and control.
Outline
Alternative Steering System Topologies
Bi-level Optimization Problem
Optimal Design Results
Conclusions
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

13. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Project Goal and Outline
Project Goal: Steering System Design
Optimal design of a steering system considering different
topologies, component sizes and control.
Outline
Alternative Steering System Topologies
Bi-level Optimization Problem
Optimal Design Results
Conclusions
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

14. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Project Goal and Outline
Project Goal: Steering System Design
Optimal design of a steering system considering different
topologies, component sizes and control.
Outline
Alternative Steering System Topologies
Bi-level Optimization Problem
Optimal Design Results
Conclusions
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

15. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Optimal Design on Hybrid Vehicles
Project Goal and Outline
Project Goal: Steering System Design
Optimal design of a steering system considering different
topologies, component sizes and control.
Outline
Alternative Steering System Topologies
Bi-level Optimization Problem
Optimal Design Results
Conclusions
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

16. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System
훿, 푇
Cylinder
Steering wheel
Torque Sensor
Rack and Pinion
Internal
Combustion
Engine
Pinion
Shaft
Belt/Gear Pump
ECU
Including valve
and reservoir
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

17. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System
훿, 푇
Cylinder
Steering wheel
Torque Sensor
Rack and Pinion
Internal
Combustion
Engine
Pinion
Shaft
Belt/Gear Pump
ECU
Including valve
and reservoir
Hydraulic power
Pump speed
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

18. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System
훿, 푇
Cylinder
Steering wheel
Torque Sensor
Rack and Pinion
Internal
Combustion
Engine
Pinion
Shaft
Belt/Gear Pump
ECU
Including valve
and reservoir
Maximally
required
power
Hydraulic power
Pump speed
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

19. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System
훿, 푇
Cylinder
Steering wheel
Torque Sensor
Rack and Pinion
Internal
Combustion
Engine
Pinion
Shaft
Belt/Gear Pump
ECU
Including valve
and reservoir
Delivered power
Maximally
required
power
Hydraulic power
Pump speed
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

20. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System
훿, 푇
Cylinder
Steering wheel
Torque Sensor
Rack and Pinion
Internal
Combustion
Engine
Pinion
Shaft
Belt/Gear Pump
ECU
Including valve
and reservoir
Delivered power
Parasitic
losses
Actually required power
Maximally
required
power
Hydraulic power
Pump speed
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

21. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Steering
Converter – Transmitter (Topology Selection) System
Source
Internal
Combustion
Engine
Fixed
Displ.
Hydraulic
Pump
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

22. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
(2)
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

23. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Σ
(3)
(2)
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

24. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Planetary
Gear Set
Σ
(4)
(3)
(2)
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

25. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Ball-screw
Gear
Planetary
Gear Set
Σ
Σ
(5)
(4)
(3)
(2)
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

26. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Ball-screw
Gear
Planetary
Gear Set
Σ
Σ
(6)
(5)
(4)
(3)
(2)
(1)
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

27. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Power Steering System Alternative Topologies
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Ball-screw
Gear
Planetary
Gear Set
Σ
Σ
(6)
(5)
(4)
(3)
(2)
(1)
1 2 i ,i
e P
z
n h f , f
l , A
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

28. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Modeling of Power Steering Topologies
FD Hydraulic Pump: Analytical models that include both
leakage losses and torque losses (! IEEE VPPC 2013)
Electric Machine: Efficiency map, scaled linearly in torque.
Alternator: Belt driven (b = 0:80), constant efficiency of
a = 0:70.
Gears: Spur, planetary and ball-screw gear sets.
Driving Cycle: a mixed cycle, predominant (85%) highway
driving, measured on a fully loaded tractor-trailer.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

29. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Modeling of Power Steering Topologies
FD Hydraulic Pump: Analytical models that include both
leakage losses and torque losses (! IEEE VPPC 2013)
Electric Machine: Efficiency map, scaled linearly in torque.
Alternator: Belt driven (b = 0:80), constant efficiency of
a = 0:70.
Gears: Spur, planetary and ball-screw gear sets.
Driving Cycle: a mixed cycle, predominant (85%) highway
driving, measured on a fully loaded tractor-trailer.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

30. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Modeling of Power Steering Topologies
FD Hydraulic Pump: Analytical models that include both
leakage losses and torque losses (! IEEE VPPC 2013)
Electric Machine: Efficiency map, scaled linearly in torque.
Alternator: Belt driven (b = 0:80), constant efficiency of
a = 0:70.
Gears: Spur, planetary and ball-screw gear sets.
Driving Cycle: a mixed cycle, predominant (85%) highway
driving, measured on a fully loaded tractor-trailer.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

31. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Modeling of Power Steering Topologies
FD Hydraulic Pump: Analytical models that include both
leakage losses and torque losses (! IEEE VPPC 2013)
Electric Machine: Efficiency map, scaled linearly in torque.
Alternator: Belt driven (b = 0:80), constant efficiency of
a = 0:70.
Gears: Spur, planetary and ball-screw gear sets.
Driving Cycle: a mixed cycle, predominant (85%) highway
driving, measured on a fully loaded tractor-trailer.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

32. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Design Space
Modeling of Power Steering Topologies
FD Hydraulic Pump: Analytical models that include both
leakage losses and torque losses (! IEEE VPPC 2013)
Electric Machine: Efficiency map, scaled linearly in torque.
Alternator: Belt driven (b = 0:80), constant efficiency of
a = 0:70.
Gears: Spur, planetary and ball-screw gear sets.
Driving Cycle: a mixed cycle, predominant (85%) highway
driving, measured on a fully loaded tractor-trailer.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

33. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Problem Definition
Optimization Problem
Optimization objective
The objective of each topology is to minimize the fuel
consumption, =
R tf
0 m_ f dt, over a given driving cycle of length
tf .
Bi-level optimization problem
Z tf
min
xc ;xdX
0
c;d (xc(t); xd )dt;
s:t: gd;c(xc(t); xd ) 0;
hd;c(xc(t); xd ) = 0:
xc = ffh; fng;
xd = fi1; i2;Pe; z; l;Ag;
fd;c = (xc; xd ) = m_ f :
Optimization constraints and variables
gd;c, hd;c, and xc;d are dictated by each topology.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

34. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Problem Definition
Optimization Problem
Optimization objective
The objective of each topology is to minimize the fuel
consumption, =
R tf
0 m_ f dt, over a given driving cycle of length
tf .
Bi-level optimization problem
Z tf
min
xc ;xdX
0
c;d (xc(t); xd )dt;
s:t: gd;c(xc(t); xd ) 0;
hd;c(xc(t); xd ) = 0:
xc = ffh; fng;
xd = fi1; i2;Pe; z; l;Ag;
fd;c = (xc; xd ) = m_ f :
Optimization constraints and variables
gd;c, hd;c, and xc;d are dictated by each topology.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

35. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Problem Definition
Optimization Problem
Optimization objective
The objective of each topology is to minimize the fuel
consumption, =
R tf
0 m_ f dt, over a given driving cycle of length
tf .
Bi-level optimization problem
Z tf
min
xc ;xdX
0
c;d (xc(t); xd )dt;
s:t: gd;c(xc(t); xd ) 0;
hd;c(xc(t); xd ) = 0:
xc = ffh; fng;
xd = fi1; i2;Pe; z; l;Ag;
fd;c = (xc; xd ) = m_ f :
Optimization constraints and variables
gd;c, hd;c, and xc;d are dictated by each topology.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

36. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Problem Definition
Optimization Problem
Topologies 2, 3 and 4 enable a controlled pump oil flow, .
The minimum flow, at certain driving conditions, is
restricted for safety reasons.
Bi-level Optimization
Sizing Optimization
Variable Flow
Control
Outer Loop
Inner Loop
Variable Flow Control Cases
(flow I): fh = 11; fn = 16
(flow II): fh = 6; fn = 16
(flow III): fh = 6; fn = 11
(flow IV):
=
r ; for r 6 L=min;
6 L=min for r 6 L=min;
r = the required flow
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

37. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Problem Definition
Optimization Problem
Topologies 2, 3 and 4 enable a controlled pump oil flow, .
The minimum flow, at certain driving conditions, is
restricted for safety reasons.
Bi-level Optimization
Sizing Optimization
Variable Flow
Control
Outer Loop
Inner Loop
Variable Flow Control Cases
(flow I): fh = 11; fn = 16
(flow II): fh = 6; fn = 16
(flow III): fh = 6; fn = 11
(flow IV):
=
r ; for r 6 L=min;
6 L=min for r 6 L=min;
r = the required flow
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

38. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Analysis
Top. 1: Hydraulic Power Steering
Infeasible Region
Minimum Flow Constraint
Fuel consumption, F
Optimal gear ration, i1
(Scaled) Gear ratio, i1 [−]
(Scaled) Average fuel consumption, F, [L/100km]
7.2
3.6
1,5 1,6 1,7 1,8 1,9 2,0
Boundary solution limited by min.
No control flexibility
Top. 2: Electro-Hydraulic Power
Steering
3 constraints min , Te and !e
not for conventional HD vehicles
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

39. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Analysis
Top. 1: Hydraulic Power Steering
Infeasible Region
Minimum Flow Constraint
Fuel consumption, F
Optimal gear ration, i1
(Scaled) Gear ratio, i1 [−]
(Scaled) Average fuel consumption, F, [L/100km]
7.2
3.6
1,5 1,6 1,7 1,8 1,9 2,0
Boundary solution limited by min.
No control flexibility
Top. 2: Electro-Hydraulic Power
Steering
3 constraints min , Te and !e
not for conventional HD vehicles
EHPS optimization − 16 L/min
Gear ratio i [−]
Electric motor rated power PEM [kW]
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
15
10
5
Infeasible region
Not simulated
Motor speed constraint
Motor torque constraint
Fuel consumption
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

40. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Analysis
Top. 4: Split Electro-Hydraulic and Hydraulic Power Steering
1 2 3 4 5 6
0.4
0.3
0.2
0.1
0
Planetary gear ratio, z [−]
Fuel consumption [L/100km]
Pareto set
Best solution
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Planetary
Gear Set
(4)
1 2 i ,i
e P
z
n h f , f
Flow IV: fuel consumption reduction up to 80% for hybrids and
up to 35% for conventional trucks (max. 2.4 kW)
The overall best topologies, 3 and 4, result in about the same
reduction of about 80%.
Added cost and complexity can be high.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

41. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Analysis
Top. 4: Split Electro-Hydraulic and Hydraulic Power Steering
1 2 3 4 5 6
0.4
0.3
0.2
0.1
0
Planetary gear ratio, z [−]
Fuel consumption [L/100km]
Pareto set
Best solution
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Planetary
Gear Set
(4)
1 2 i ,i
e P
z
n h f , f
Flow IV: fuel consumption reduction up to 80% for hybrids and
up to 35% for conventional trucks (max. 2.4 kW)
The overall best topologies, 3 and 4, result in about the same
reduction of about 80%.
Added cost and complexity can be high.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

42. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Comparison
Top. 1 Top. 2 Top. 3 Top. 4 Top. 5 Top. 6
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Average fuel consumption, F, [L/100km]
Fixed flow
Variable flow I
Variable flow II
Variable flow III
Variable flow IV
lowering the minimum flow, hl , improves the fuel efficiency.
top. 3,4,5 can also be suitable for conventional trucks
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

43. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Results
Results Comparison
Top. 1 Top. 2 Top. 3 Top. 4 Top. 5 Top. 6
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Average fuel consumption, F, [L/100km]
Fixed flow
Variable flow I
Variable flow II
Variable flow III
Variable flow IV
lowering the minimum flow, hl , improves the fuel efficiency.
top. 3,4,5 can also be suitable for conventional trucks
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

44. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Summary
Nested optimization approach has resulted in optimal
design and control of the power steering pump
The electrification of the PSP can reduce fuel consumption
by more than 80% when compared with hydraulic steering
and enables Start/Stop and Zero Emission Driving;
Future work
Adress more auxiliaries and critical secondary aspects
(e.g., cost, steering performance) for design.
Integrate auxiliary design with powertrain components
design for topology, sizing and control.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

45. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Summary
Nested optimization approach has resulted in optimal
design and control of the power steering pump
The electrification of the PSP can reduce fuel consumption
by more than 80% when compared with hydraulic steering
and enables Start/Stop and Zero Emission Driving;
Future work
Adress more auxiliaries and critical secondary aspects
(e.g., cost, steering performance) for design.
Integrate auxiliary design with powertrain components
design for topology, sizing and control.
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

46. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Thank you!
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

47. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Extra Slides
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

48. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Optimization Problem
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
(2)
(1)
1 i
e P
n h f , f
Topology 1: xd = fi1g; xc = ;
Topology 2: xd = fi1;Peg; xc = ffn; fhg
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV

49. Why SDL? Designed Topologies Optimization Problem Results Conclusions
Conclusions
Optimization Problem
Belt/
Gear
Electric
Machine
Steering
Converter – Transmitter (Topology Selection) System
Internal
Combustion
Engine
Alternator
Source
Fixed
Displ.
Hydraulic
Pump
Ball-screw
Gear
Planetary
Gear Set
(6)
(4)
1 2 i ,i
e P
z
n h f , f
l
Topology 4: xd = fi1;Peg; xc = ffn; fhg
Topology 6: xd = fi2;Pe; lg; xc = ;
Emilia Silvas (e.silvas@tue.nl) Multi-level optimal design of HEV