【Listening】

【Vocabulary & Phrases】

suspension system悬架系统、行驶系统

spring弹簧

shock absorber减震器

linkage连杆机构

roadholding行驶性能

handling操控性能

braking制动性能

active safety主动安全性

noise噪音

bump撞击

vibration振动

shock振动

cargo货物

luggage行李

front suspension前悬架

rear suspension后悬架

alignment 校准

compression压缩

attachment附件

【Reading】

SuspensionSystem

Principle of Suspension

Suspension is the term given to the system ofsprings, shock absorbers and linkages that connects a vehicle to its wheels.

Suspension systems serve a dual purpose –contributing to the car's roadholding /handling and braking for good activesafety and driving pleasure, and keeping vehicle occupants comfortable andreasonably well isolated from road noise, bumps, and vibrations, etc. The mainpurpose is to prevent large shocks, caused by the wheels striking bumps in theroad, being passed to the vehicle occupants and components; otherwisediscomfort and damage would occur.

These goals are generally at odds, so the tuning ofsuspensions involves finding the right compromise. It is important for thesuspension to keep the road wheel in contact with the road surface as much aspossible, because all the forces acting on the vehicle do so through thecontact patches of the tires. The suspension also protects the vehicle itselfand any cargo or luggage from damage and wear. The design of front and rearsuspension of a car may be different.

The suspension system has two subsystems-the frontsuspension and the rear suspension. The front suspension is more complicatedthan the rear suspension. This is because the front wheels must move in severaldifferent directions. The wheels must move up and down with the suspension andturn left to right with the steering. Since the car goes in the direction inwhich the front wheels point, the alignment of the front wheels is important.Poor alignment can make a car pull to one side and stop the front wheels fromreturning to the straight-ahead position after a turn.

In a typical suspension system for a vehicle withfront-engine and front-wheel drive, the weight of the vehicle applies aninitial compression to the coil springs. When the tires and wheels encounterirregularities in the road, the springs further compress or expand to absorbmost of the shock. The suspension at the rear wheels is usually simpler thanfor the front wheels, which require multiple-point attachments so the wheelscan move up and down while swinging from side to side for steering.

【随堂测试】