Electro-mechanical Steering System

1. ELECTRO-MECHANICAL STEERING SYSTEM

SUBMITTED BYPAPPOO YADAV
SR NO - 567/12

2. BRIEF HISTORY

The first automobiles were
steered with a tiller.
A steering wheel was first
used in Europe in 1894 .
Bicycles, Mobility scooters
are often using tiller
steering.

3. OTHER FEATURES…

It helps in swinging the wheels to the left or right.
It converts the rotary movement of the steering wheel
into an angular turn of the front wheels.
It multiplies the effort of the driver by leverage in order
to make it fairly easy to turn the wheels.
It absorbs a major part of the road shocks thereby
preventing them to get transmitted to the hands of the
driver

4. BASIC STEERING MECHANISM

Ackerman steering
system
Davis steering system
Projected center lines of
all should meet on or
near the centre of the
rear axle.

5. TYPES OF STEERING SYTEM

RECIRCULATING OR PARALLELOGRAM
STEERING SYSTEM
RACK AND PINION TYPE STEERING SYSTEM
Any vehicle (heavy,small,medium) must have these two
steering system whether they have any type of power steering.

6. RECIRCULATING TYPE

7. RECIRCULATING GEAR BOX

It consists of a worm at the
end of steering rod.
The balls reduce the
friction during the
movement of the nut on the
worm.
The nut has a number of
teeth on outside, which
mesh with the teeth on a
worm wheel sector.
Used for heavy vehicle like
trucks, buses etc.

8. RACK AND PINION TYPE

9. RACK AND PINION GEAR BOX

• Some cars have variableratio steering, which uses a
rack-and-pinion gear set
that has a different tooth
pitch (number of teeth per
inch) in the center than it
has on the outside.
• This makes the car
respond quickly when
starting a turn (the rack is
near the center), and also
reduces effort near the
wheel's turning limit.
• Used in small and medium
vehicles like cars,suv,racing
cars etc.

10. WHEEL ALIGNMENT

CAMBER ANGLE
CASTER ANGLE
TOE-IN AND TOE-OUT
KING PIN INCLINATION

11. WHEEL ALIGNMMENT

Why is it necessary?
Directional stability
Maintain straightness
Reduce uneven wear of tyres
Proper traction between tyres and road while
turning

12. POWER STEERING

1. Hydraulic power steering(HPS)
2. Electro-mechanical steering system or electric
steering system (EPS)
3. Electro hydraulic steering system(EHPS)
4. Hydrostatic steering system (no mechanical
linkage, used in tractor, roller, bulldozer )

13. ELECTRO MECHANICAL STEERING SYSTEM

Why we need for this while we have manual as
well as hydraulics steering system?

14. PROS OF EPS

Less complicated
Usually less weighs
There is no such fluid needed thus it needs less
maintenance compared to hydraulic power
steering.
Better response at different speeds
It supports return of the steering wheel back to the
center position via the “active return”
function.
It consumes power from battery, but it consumes
less power compared to HPS. So a car having EPS
will give more mileage than one with HPS.
Straight-line stability function
No continuous power taking

15. EPS

• Electric Power Steering (EPS) is the latest system in which
the electric motor (“E-motor”) is attached.
• Sensors detect the motion of the steering column and a
processor module applies assistive power via an electric
motor. This allows varying amounts of assistance depending
on driving conditions.
• With electronic systems becoming more and more common
in cars, EPS is the future power steering system that they
will use.
• EPS is active only during the actual steering process.
• The sum of the turning force on the steering wheel and the
assisting force is the effective force applied on the steering
gear to move the rack.

16. DIFFERENT EPS SYSTEM THAT ARE IN USE

A. COLUMN TYPE
The column drive is used
for small and lower midsized cars. The motor is
located in the passenger
compartment.
Its advantage is its better
performance at reduced
temperatures, and
sealing.

17. DIFFERENT EPS SYSTEM THAT ARE IN USE

B. DUAL PINION TYPE
• The dual pinion drive is
used for mid-sized cars.
• This drive is located in
the engine
compartment

18. DIFFERENT EPS SYSTEM THAT ARE IN USE

C. RACK TYPE
This type is
appropriate for large
vehicles such as Sports
Utility Vehicles(SUVs)
and trucks

19. EPS COMPONENTS

1.
2.
3.
4.
5.
6.
7.
8.
Steering wheel
Steering Angle Sensor
G85
Steering column
Steering Torque Sensor
G269
Steering gear
Electro-mechanical
Power Steering
Motor V187
Power Steering Control
Module J500

20. SYSTEM OVERVIEW

21. STEERING FUNCTION

1. The power steering assistance starts
when the driver uses force to turn the
steering wheel
2. The Steering Torque Sensor
detects the rotation and sends the
calculated steering force figure to the
Power Steering Control Module.
3. The Steering Angle Sensor reports
the current steering angle and steering
speed.

22. STEERING FUNCTION

4. Depending on the steering force, road
speed, engine speed, steering angle,
steering speed and maps stored in Power
Steering Control Module , it calculates
the necessary assisting force and
actuates EMPS Motor.
5. The steering assistance comes from a
second pinion, which applies its energy
in parallel on the steering rack. This
pinion is driven by EMPS Motor.
6. The sum of the turning force on the
steering wheel and the assisting force
is the effective force applied on the
steering gear to move the rack.

23. STEERING FUNCTION

Electro-mechanical Power
Steering Indicator Lamp
EMPS Indicator Lamp light up
in two colors if functional
faults are detected.
If it lights up yellow, the
warning is of a lower priority.
If it lights up red, the vehicle
should be serviced
immediately
Once Power Steering Control
Module receives a signal,
indicating that all systems are
working correctly, EMPS
Indicator Lamp will go out.

24. CONTROL MAP CHARACTERISTICS

25. ENERGY COSUMPTION

100
90
80
70
60
100
50
40
60
30
35
20
10
10
0
EPS
EHPS
HPS
HSPS

26. CONCLUSION

EPS reduces the human effort up to 80 percent so
upcoming year of steering will be of EPS in all type of
vehicle.
EPS will become most efficient, safe and reliable power
steering system in the future .
The key to the success of EPS is an accurate and quick
response, so it will be used in F1 racing cars in upcoming
years.
Program for control module IC can be changed according
to need of assisting force. So it will be beneficial for
different types of road.
This year, in auto spa Delhi, mostly cars manufactured by
different company were launched with EPS.

27. REFERENCES

www.autoshop101.com/forms/Hybrid17.pdf
http://www.volkspage.net/technik/ssp/ssp/SSP_225.pd
f self study program 259
http://www.howeperformance.com/rockcrawling.html
R.K.RAJPUT, 2009-10 , “AUTOMOBILE ENGINEERING”
M.F. Rehman, “ELECTRIC POWER ASSISTED STEERING
SYSTEM FOR AUTOMOBILES”, Electrical Engineering
Vol.3.
Ratan S., Tata McGraw Hills publication , “Theory of
Machines” Vol 1,
www.infineon.com/electric power steering.pdf/Edition
2008-10-23