Geely EC718, EC718RV, EC715, EC715RV. Manual part — 269

Metric (mm)

US English (in)

Front Wheel Upper Run Out

80

3.1

Front Wheel Lower Run Out

80

3.1

Suspension System

Front Suspension

4-5

4.2.2 Description and Operation
4.2.2.1 Description and Operation

The function of the front suspension system is to maximize the
friction between tires and road surface, provide good steering
control and stability, ensure passenger comfort. It is able to
absorb the energy of the wheel vertical acceleration, so when
the wheels move up and down along the bumpy road the frame
and body will not be interfered. This vehicle uses independent
strut front suspension, which includes the following
components: springs, shock absorbers and the stabilizer bar.

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Front Suspension

Suspension System

4.2.3 System Working Principle
4.2.3.1 Suspension System Terms

1. Sprung Load:

•

Sprung load refers to the weight supported by the spring.

•

Sprung load should be larger than the non-Sprung Load to
get the normal handling performance.

Sprung Load Examples:

a. Body and Frame

b. Load or Cargo

c. Fuel Tank

Spring Components:

a. Frame (Including the subframe)

b. Body (Including the whole body)

c. Power System (Engine, Transmission, Differential, Drive

Axle)

d. Steering

2. Non-Sprung Load:

•

Non-Sprung load refers to the weight not supported by the
spring

•

The less the non-Sprung Load the better, in order to ensure
the normal handling and ride comfort.

Non-Sprung Load Examples:

a. Wheels and Tires

b. Wheel Bearings and Hub

c. Axle and Steering Knuckle

d. brake parts (mounted on wheels)

Non-Sprung Load Components:

a. Wheels / Tires, Ball Joint, Bearings, Control Arm, Beam,

Cross Members, Overall Drive Axle

b. Stabilizer Bar, Control Rod, etc.

c. Shaft, Steering Knuckle, Brake, etc.

d. Non-Sprung load is small then the suspension response is

good.

3. Components Between Sprung Load and
Non-Sprung Load:

Steering rod, drive axle, stabilizer bar and other components
installed between the sprung load and the non-sprung load.

4.2.3.2 Suspension System Component
Working Principle

1. Spring:

Spring stiffness will affect the Sprung Load response quality
during driving. If the spring is soft, it can eliminate bumps and
provide a very smooth driving feel, but in the process of braking
and acceleration, it feels crawling and crouching. In the corner,
it intends to roll and tumble. If the spring is firm, it feels less
smooth on bumpy roads, but the body movement is very small,
which means that even in the corner, you can also drive the
vehicle fast. The spring itself is simple. Designing,
implementing these devices and finding balance between the
passenger comfort and vehicle handling performance is not
easy. Smooth driving feel can not be achieved alone by the
spring. The spring absorbing energy ability is excellent, but the
dissipation ability is less impressive. Therefore, the suspension
system uses a device called on shock absorber. If the damping
structure is not used, spring will bounce at an uncontrolled rate
and release the energy it absorbed through bumping and
continue to bounce at its own frequency until it runs out all the
energy. Built on the spring, the suspension allows the vehicle
to drive on bumpy roads without losing control.

2. Shock Absorber:

7

1

5

6

3

4

2

FE04-1001b

1. Piston Rod
2. Inner Cylinder

Suspension System

Front Suspension

4-7

3. Outer Tube
4. Hydraulic Chamber
5. Piston and Valve
6. Liquid Storage Space
7. Inner Cylinder Bottom Valve
It controls the unwanted spring movement through a process
known as damping. Shock absorber converts the suspension
kinetic energy to heat dissipated by the hydraulic fluid to slow
and weaken the vibration movement. Shock absorber upper
bearing is connected to the frame (ie. Sprung Load), lower
bearing is connected to the axle (ie. non-Sprung Load). In the
double-cylinder design, one of the most common types of
shock absorber is that the upper bearing is connected to the
piston rod, piston rod is connected to the piston and piston is
in the cylinder filled with hydraulic fluid. Inner cylinder is known
as the pressure cylinder, outer cylinder is known as the
reservoir cylinder. Reservoir cylinder stores the extra hydraulic
fluid. When the wheels encounter bumps along the road and
the spring is compressed or stretched, the spring energy
passes through the bearing to the shock absorber, and passes
down through the piston rod to the piston. There are holes on
the piston. When the piston moves up and down in the pressure
cylinder, hydraulic fluid may leak through these holes. Because
these holes are very small, so even under a lot of pressure only
a small amount hydraulic fluid can leak through. This slows
down the velocity of the piston, so it slows down the spring
movement. Shock Absorber's work consists of two cycles -
compression cycle and extension cycle. Compression cycle is
when the piston moves downward to compress the hydraulic
fluid beneath it; extension cycle is when the piston moves
upward to compress the hydraulic fluid on the top. For a typical
vehicle, the extension cycle resistance is greater than its
compression cycle. Moreover, please note that compression
cycle control is related to the non-sprung load movement, while
the extension cycle control is related to heavier Sprung Load
movement. All modern shock absorbers come with speed-
sensing capabilities - the faster the suspension speed, the
greater the resistance shock absorber provides. This makes
the shock absorber can be adjusted according to road
conditions and controls the vehicle to eliminate unwanted
movements, including bounce, roll, brake dive and acceleration
squat and so on.

3. Stabilizer Bar:

It is used in conjunction with the shock absorber to provide
additional stability for the driving vehicle. Stabilizer is a metal
bar across the axle, effectively connecting the suspension on
both sides together. When a wheel moves up and down on the

suspension, stabilizer bar will pass the movement to the other
wheel. This can make driving more stable and reduce the
vehicle inclination. In particular, it is capable to compensate the
vehicle rollover tendency when the vehicle is turning.

4-8

Front Suspension

Suspension System