electro mechanical steering system- most advance technology
TRANSCRIPT
ELECTRO-MECHANICAL STEERING SYSTEM
SUBMITTED BY-PAPPOO YADAVSR NO - 567/12
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.
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
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.
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.
RECIRCULATING TYPE
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.
RACK AND PINION TYPE
RACK AND PINION GEAR BOX
• Some cars have variable-ratio 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.
WHEEL ALIGNMENT
CAMBER ANGLECASTER ANGLETOE-IN AND TOE-OUTKING PIN INCLINATION
WHEEL ALIGNMMENT
Why is it necessary?
Directional stabilityMaintain straightnessReduce uneven wear of tyresProper traction between tyres and road while
turning
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 )
ELECTRO MECHANICAL STEERING SYSTEM
Why we need for this while we have manual as well as hydraulics steering system?
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
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.
DIFFERENT EPS SYSTEM THAT ARE IN USE
A. COLUMN TYPE The column drive is used
for small and lower mid-sized cars. The motor is located in the passenger compartment.
Its advantage is its better performance at reduced temperatures, and sealing.
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
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
EPS COMPONENTS
1. Steering wheel2. Steering Angle Sensor G853. Steering column4. Steering Torque Sensor
G2695. Steering gear6. Electro-mechanical Power
Steering7. Motor V1878. Power Steering Control
Module J500
SYSTEM OVERVIEW
STEERING FUNCTION1. 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.
STEERING FUNCTION4. 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 asecond pinion, which applies its energyin parallel on the steering rack. Thispinion is driven by EMPS Motor.
6. The sum of the turning force on thesteering wheel and the assisting forceis the effective force applied on thesteering gear to move the rack.
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.
CONTROL MAP CHARACTERISTICS
ENERGY COSUMPTION
EPS EHPS HPS HSPS0
10
20
30
40
50
60
70
80
90
100
10
35
60
100
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.
REFERENCES
www.autoshop101.com/forms/Hybrid17.pdf http://www.volkspage.net/technik/ssp/ssp/SSP_225.pdf
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