SsangYong Korando III (2010 year). Manual - part 559

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3. DIFFERENCES BETWEEN HPS AND EPS

HPS

EPS

1 

Crankshaft pulley (DDU)

2 Auto 

tensioner

3 Tensioner 

pulley

4 Vacuum 

pump

5 

A/C compressor pulley

6 Alternator 

pulley

7 

Water pump pulley

8 

No.1 idle pulley

9 

No.2 idle pulley

10 

Power steering pump

-

HPS (Hydraulic Power Steering)

EPS (Electric Power Steering)

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Hydraulic power steering

Electric power steering

1. OVERVIEW

The electric power steering, EPS, does not have any belt-driven steering pump constantly running, so it 
is lightweight and the motor consumes energy only when the steering wheel is turned by the driver, and 
this leads to improvement in fuel efficiency. Also, the elimination of a belt-driven pump and its 
accessories greatly simplifies manufacturing and maintenance. While offering these benefits, as it does 
not contain any steering oil, the environment is not polluted both when the steering system is produced 
and discarded.
In other words, the electric power steering (EPS) system uses the electric motor to assist the steering 
force. It functions independently regardless of whether the engine is running or not, unlike the existing 
hydraulic power steering.
The EPS system generates an assist steering force variably depending on the driving conditions by 
controlling the motor's operation, based on the input signals from the sensors such as torque sensor and 
angle sensor. In turn, the EPS receives the torque signal by the driver's movements of the steering 
wheel, as well as the vehicle speed, and uses the motor to determine the assist torque. The EPS 
controls the motor for this. Another features of EPS are fail-safe function, diagnosis function, 
communication function between units and interface function for external diagnostic device.
The EPS system components such as the torque sensor, steering angle sensor, fail-safe relay, etc. are 
located in the steering column and EPS unit assembly.

Advantages:

▶

Assurance of improved steering
Provides optimal steering force according to the 
vehicle speed
Enhanced steering stability while driving at high 
speed

(1)

-

-

Reduced fuel consumption
Consumes energy only when steering wheel 
is turned (improved by 3 to 5%)
Energy saving (reduced by 85% compared 
with hydraulic power steering)
Reduced number of parts: Elimination of 
steering pump, hydraulic hose, pump pulley, 
oil reservoir, belt, bracket, etc.

(2)

-

-

-

Comparison between hydraulic power steering and electric power steering (EPS)

▶

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2. OPERATION

When the driver turns the steering wheel, a torque is generated and the torque sensor and the steering 

angle sensor in the EPS system detect the rotation of the steering column to run the electric motor. At 

this time, the worm gear connected to the motor drives the helical gear mounted to the steering column 

to generate the assist torque for the steering column. This allows the driver to operate the steering wheel 

easier.

Output torque = 1) Steering force (manual torque) + 2) Assist torque

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1. SPECIFICATION

Description

Specification

Remark

Tire

16 inch

215 / 65R 16

Standard

17 inch

225 / 60R 17

Optional

18 inch

225 / 55R 18

Optional

Tire inflation pressure

32psi

-

Wheel

16 inch

6.5 J X 16

Standard

17 inch

6.5 J X 17

Optional

18 inch

6.5 J X 18

Optional

Balance weight

Inner: Clip-on type

Outer: Adhesive type

-
-

Tightening torquse of wheel bolt

127.4 ~ 156.8 Nm

17mm X 5 

(Length:56.5 mm)