UNIT 12
BODY ELECTRICAL SYSTEMS
TEXT A
Supplemental Restraint System
PROFESSIONAL ENGLISH
TEXT A
Wheel Alignment
System Operation
System Components
Airbag Deactivation
Smart Systems
Service Precautions
Handling a Live Air Bag Module
Handling a Deployed Air Bag Module
Disarming the System
Arming the System
本次课学习内容本次课学习目标
掌握 airbag的英文专业词汇
训练快速阅读能力，提高阅读速度
NEW WORDS
restraint [ris'treint] n.约束，抑制,制止,克制
head-on [hed?n] a.正面的
brick [brik] n.砖,砖形物
potassium [p?'t?sj?
m]
n.钾
sodium ['s?udj?
m]
n.钠
azide ['? zaid] n.叠氮化物
nitrate ['naitreit] n.硝酸盐,硝酸钾
blast [blɑ:st] n.一阵 (风 ),一股 (气流 ),冲击波
cowl [kaul] n.壳，罩
fender ['fend?] n.挡泥板
severity [si'veriti] n.严重（性）,激烈，严酷程度
ribbon-like ['rib?n'laik] a.带状的
inflator [in'fleit?
(r)]
n.充气器,充气机,打气筒
decorative ['dek?r?tiv] a.装饰的
overly ['?uv?li] ad.过度地,极度地
infrared ['infr?'red] a.红外线的 ; n.红外线
accordingly [?'k?:di?li] ad.因此,从而，相应地
capacitive [k?'p?siti
v]
a.电容性的
reflective [ri'flektiv] a.反射的
dashboard ['d?∫?b?:d] n.仪表板
discriminate [dis'krimi
neit]
v.区别,区别对待，歧视,
inanimate [in'? nimit] a.死气沉沉的,没生命的,单调的
grocery ['gr?us?ri] n.食品,杂货
updated [?p'deitid] a.最新的，现代化的
pretensioner [pri:'ten∫
n?]
n.预紧器
commence [k?'mens] v.开始,着手
substitute ['s?bstitju
:t]
v.代替,替换 ; n.代用品,替代品
inferior [in'fi?ri?] a.下等的,差的,自卑的
fastener ['fɑ:sn?] n.紧固件，接合件，固定器，扣闩
live [liv] a.活的,精力充沛的； v.活着,生活
hydroxide [hai'dr?
ksaid]
n.氢氧化物
irritate ['iriteit] v.刺激，激怒,使急躁
nasal ['neiz?l] a.鼻子的,鼻音的,
vacuum ['v? kju
m]
n.真空,真空吸尘器； v.用真空吸尘器打扫
expel [iks'pel] v.排出,开除,驱逐
plenum ['pli:n?
m]
n.压力通风系统，强制通风；充实,
充满
dispose [dis'p?u
z]
v.处理,处置
trash [tr?∫] n.无价值之物,垃圾,废料 [物 ]
wrap [r? p] v,& n.包裹,缠绕
PHRASES AND EXPRESSIONS
supplemental
restraint system
乘员约束辅助保护装置（ SRS）
in concert with 与 … 合作
front impact sensor 正面碰撞传感器
clock spring 钟弹簧，盘旋电缆
sodium azide 叠氮化钠
potassium nitrate 硝酸钾
energy reserve
capacitor
储能电容器
forward sensor 前传感器
safing sensor 保险传感器
over the way 路对面，街对面
out of the way 向旁边，不再挡路，不再碍事
smart airbag 智能传感器
service package 修理包
sodium hydroxide 氢氧化钠
vacuum cleaner 真空吸尘器
local authority 地方当局，地方政府
Supplemental Restraint System
System Operation
The supplemental restraint system (SRS) is designed to work in
concert with the seat belts to further prevent personal injury during
a head-on collision with another object,The SRS utilizes an air bag
module,front impact sensors,a clock spring,low pressure switch
and a diagnostic module.
With the battery cables connected,the SRS system is energized
and monitoring the forward impact sensors and the safing sensor for
collision confirmation messages,When the vehicle strikes,or is
struck by,another object (such as a tree,wall,another vehicle,etc.),
the forward impact sensors and safing sensor send impulses to the
diagnostic module,which determines the force and direction of the
impact,Based on this information the diagnostic module either
deploys or does not deploy the air bag,Inflation happens when
there is a collision force equal to running into a brick wall at 10 to 15
miles per hour (16 to 24 km per hour),The airbag's inflation system
reacts sodium azide (NaN3) with potassium nitrate (KNO3) to
produce nitrogen gas (Fig.12-1),Hot blasts of the nitrogen inflate
the airbag.
System Components
Control Module
The air bag control module or SRS ECU is one of the most visible
part of the system,It contains the air bag safing sensor and
energy reserve capacitor,The module is mounted on the tunnel
floor pan forward of the center console,Some safing sensor is
located inside the control module,The safing sensor provides
confirmation of a crash,but does not determine the severity,
The control module monitors the system to determine the
system readiness,The control module will store a sufficient
energy to deploy the airbags for only two minutes after the
battery has been disconnected,The control module contains on-
board diagnostics,and will illuminate the AIR BAG warning lamp
on the dash when a fault has occurred,The warning equipment is
tested for a few seconds every time the vehicle is started,
Front Impact Sensors
By function,there are 2 types of front impact sensors,forward
impact sensors and safing sensors,
The forward sensors are located in various locations forward of
the passenger compartment,Some are located inside the fenders,
some are on the cowl,some are attached to the support in front
of the radiator.
Rear sensors are also known as safing sensors as their function
is to determine that a crash has occurred,Rear safing sensors are
located in various locations in the passenger compartment
depending on the manufacturer,Some are integrated with the
control/diagnostic module.
The rear safing sensor must close before the forward sensors to
avoid airbag deployment in cases where the impact is not severe
enough to cause deployment [1],When the vehicle is parked with
the ignition off deployment is very unlikely because there is no
power to the circuits for deployment,
The two front impact sensors provide verification of the direction
and severity of the impact,The impact sensors are threshold
sensitive switches that complete an electrical circuit when an
impact provides a sufficient inertia force to close the switch
(Fig.12-2),The sensors are calibrated for the specific vehicle and
react to the severity and direction of the impact,
Clock Spring
The clock spring is mounted on the steering column behind the
steering wheel and is used to maintain a continuous electrical circuit
between the wiring harness and the driver's air bag module,This
assembly consists of a flat ribbon-like electrically conductive tape
which winds and unwinds with the steering wheel rotation [2].
Air Bag Module
The driver air bag module is located on the steering wheel and is
the most visible part of the system,It contains the air bag cushion
and its supporting components,The module contains a housing to
which the cushion and inflator are attached and sealed.
The driver side inflator assembly is mounted from the back of the
module housing,When supplied with the proper electrical signal the
inflator assembly will produce a gas and discharge it directly into the
cushion,
A protective cover is fitted to the front of the driver air bag
module and forms a decorative cover in the center of the
steering wheel,The driver air bag module is mounted directly to
the steering wheel.
The passenger air bag module is located beneath the decorative
cover of the instrument panel,facing the passenger seat,The
passenger inflator is within the module housing,The module is
mounted to the upper and lower instrument panel,A protective
cover is fitted into the instrument panel over the way passenger
air bag module,This cover will pivot out of the way and allow the
cushion to fully inflate.
Airbag Deactivation
In response to concerns about children -- and others,especially
smaller people -- being killed or seriously injured by malfunctioning or
overly powerful airbags,the National Highway Traffic Safety
Administration (NHTSA) in 1997 issued a final rule to allow auto
manufacturers to use lower-powered airbags,This rule permits
airbags to be depowered by 20 to 35 percent,In addition,starting in
1998,repair shops and dealers were allowed to install on/off switches
that allow airbags to be deactivated.
Smart Systems
The smart airbag of the future is not just the airbag,but a redesign
of the components in the current airbag systems,Features include,
Weight Sensors This is a new sensor for the passenger seat to
classify the weight and to determine what type of occupant is in the
seat,adult or child,
Infrared Occupant Detection This system will use infra-red beams
(just like in your TV remote control) to detect the distance the
passenger is from the airbag and adapt the force of deployment
accordingly,
Capacitive Reflective Occupant Sensing These sensors will be
located in the seat backs and in the dash to identify the distance
you and or your passengers are from the dashboard,These
sensors will be able to discriminate between a human occupant
and inanimate objects like your groceries,This alone will save
thousands of dollars in the cases where the driver is the only
occupant in the front seat,
Updated Sensors The updated sensors will have the capabilities
of deploying the seatbelt pretensioners faster,so in a crash
situation you will be in the best position to benefit from the
airbag deployment,
Centralized Electronic Control Unit The new control units will be
able use all the input from the new sensor technology and thru
new software deploy what you need when you need it,
Service Precautions
When working on the SRS or any components which require
the removal of the air bag,adhere to all of these precautions to
minimize the risks of personal injury or component damage:
·Before attempting to diagnose,remove or install the air bag
system components,you must first disconnect and isolate the
negative (-) battery cable,Failure to do so could result in
accidental deployment and possible personal injury.
·When an undeployed air bag assembly is to be removed from
the steering wheel,after disconnecting the negative battery
cable,allow the system capacitor to discharge for two minutes
(Chrysler) before commencing with the air bag system
component removal.
·Replace the air bag system components only with specified
replacement parts,or equivalent.
Substitute parts may visually appear interchangeable,but
internal differences may result in inferior occupant protection.
·The fasteners,screws,and bolts originally used for the SRS
have special coatings and are specifically designed for the SRS,
They must never be replaced with any substitutes,Anytime a
new fastener is needed,replace with the correct fasteners
provided in the service package or fasteners listed in the parts
books.
Handling a Live Air Bag Module
At no time should any source of electricity be permitted near
the inflator on the back of the module [3],When carrying a
live module,the trim cover should be pointed away from the
body to minimize injury in the event of accidental deployment,
In addition,if the module is placed on a bench or other
surface,the plastic trim cover should be face up to minimize
movement in case of accidental deployment.
When handling a steering column with an air bag module
attached,never place the column on the floor or other
surface with the steering wheel or module face down,
Handling a Deployed Air Bag Module
The vehicle interior may contain a very small amount of
sodium hydroxide powder,a by-product of air bag
deployment,Since this powder can irritate the skin,eyes,
nose or throat,be sure to wear safety glasses,rubber gloves
and long sleeves during cleanup.
If you find that the cleanup is irritating your skin,run cool
water over the affected area,Also,if you experience nasal or
throat irritation,exit the vehicle for fresh air until the irritation
ceases,if irritation continues,see a physician.
Begin the cleanup by putting tape over the two air bag exhaust
vents so that no additional powder will find its way into the vehicle
interior,Then remove the air bag and air bag module from the
vehicle.
Use a vacuum cleaner to remove any residual powder from the
vehicle interior,Work from the outside in so that you avoid
kneeling or sitting in an uncleaned area,
Be sure to vacuum the heater and A/C outlets as well,In fact it's a
good idea to run the blower on low and to vacuum up any powder
expelled from the plenum,You may need to vacuum the interior of
the car a second time to recover all of the powder.
Check with the local authorities before disposing of the
deployed bag and module in your trash.
After an air bag has been deployed,the air bag module and
clock spring must be replaced because they cannot be reused,
Other air bag system components should be replaced with new
ones if damaged.
Disarming the System
CAUTION
The Supplemental Restraint System (SRS) system must be
disarmed before repair and/or removal of any component in its
immediate area including the air bag itself,Failure to do so may
cause accidental deployment of the air bag,resulting in
unnecessary SRS system repairs and/or personal injury.
1,Disconnect the negative battery cable and isolate the cable
using an appropriate insulator (wrap with quality electrical
tape).
Always wear safety goggles when working with,or around,
the air bag system.
2,Allow the system capacitor to discharge for 2 minutes
(CHRYSLER) before starting any repair on any air bag
system or related components,This will disable the air bag
system.
Arming the System
To arm the SRS,reconnect the negative battery cable,This
will automatically enable the air bag system.
小结
System Operation
System Components
Airbag Deactivation
Smart Systems
Service Precautions
Handling a Live Air Bag Module
Handling a Deployed Air Bag Module
Disarming the System
Arming the System
作业
熟记相关专业词汇
P270 EXERCIES Ⅰ &Ⅱ
BODY ELECTRICAL SYSTEMS
TEXT A
Supplemental Restraint System
PROFESSIONAL ENGLISH
TEXT A
Wheel Alignment
System Operation
System Components
Airbag Deactivation
Smart Systems
Service Precautions
Handling a Live Air Bag Module
Handling a Deployed Air Bag Module
Disarming the System
Arming the System
本次课学习内容本次课学习目标
掌握 airbag的英文专业词汇
训练快速阅读能力，提高阅读速度
NEW WORDS
restraint [ris'treint] n.约束，抑制,制止,克制
head-on [hed?n] a.正面的
brick [brik] n.砖,砖形物
potassium [p?'t?sj?
m]
n.钾
sodium ['s?udj?
m]
n.钠
azide ['? zaid] n.叠氮化物
nitrate ['naitreit] n.硝酸盐,硝酸钾
blast [blɑ:st] n.一阵 (风 ),一股 (气流 ),冲击波
cowl [kaul] n.壳，罩
fender ['fend?] n.挡泥板
severity [si'veriti] n.严重（性）,激烈，严酷程度
ribbon-like ['rib?n'laik] a.带状的
inflator [in'fleit?
(r)]
n.充气器,充气机,打气筒
decorative ['dek?r?tiv] a.装饰的
overly ['?uv?li] ad.过度地,极度地
infrared ['infr?'red] a.红外线的 ; n.红外线
accordingly [?'k?:di?li] ad.因此,从而，相应地
capacitive [k?'p?siti
v]
a.电容性的
reflective [ri'flektiv] a.反射的
dashboard ['d?∫?b?:d] n.仪表板
discriminate [dis'krimi
neit]
v.区别,区别对待，歧视,
inanimate [in'? nimit] a.死气沉沉的,没生命的,单调的
grocery ['gr?us?ri] n.食品,杂货
updated [?p'deitid] a.最新的，现代化的
pretensioner [pri:'ten∫
n?]
n.预紧器
commence [k?'mens] v.开始,着手
substitute ['s?bstitju
:t]
v.代替,替换 ; n.代用品,替代品
inferior [in'fi?ri?] a.下等的,差的,自卑的
fastener ['fɑ:sn?] n.紧固件，接合件，固定器，扣闩
live [liv] a.活的,精力充沛的； v.活着,生活
hydroxide [hai'dr?
ksaid]
n.氢氧化物
irritate ['iriteit] v.刺激，激怒,使急躁
nasal ['neiz?l] a.鼻子的,鼻音的,
vacuum ['v? kju
m]
n.真空,真空吸尘器； v.用真空吸尘器打扫
expel [iks'pel] v.排出,开除,驱逐
plenum ['pli:n?
m]
n.压力通风系统，强制通风；充实,
充满
dispose [dis'p?u
z]
v.处理,处置
trash [tr?∫] n.无价值之物,垃圾,废料 [物 ]
wrap [r? p] v,& n.包裹,缠绕
PHRASES AND EXPRESSIONS
supplemental
restraint system
乘员约束辅助保护装置（ SRS）
in concert with 与 … 合作
front impact sensor 正面碰撞传感器
clock spring 钟弹簧，盘旋电缆
sodium azide 叠氮化钠
potassium nitrate 硝酸钾
energy reserve
capacitor
储能电容器
forward sensor 前传感器
safing sensor 保险传感器
over the way 路对面，街对面
out of the way 向旁边，不再挡路，不再碍事
smart airbag 智能传感器
service package 修理包
sodium hydroxide 氢氧化钠
vacuum cleaner 真空吸尘器
local authority 地方当局，地方政府
Supplemental Restraint System
System Operation
The supplemental restraint system (SRS) is designed to work in
concert with the seat belts to further prevent personal injury during
a head-on collision with another object,The SRS utilizes an air bag
module,front impact sensors,a clock spring,low pressure switch
and a diagnostic module.
With the battery cables connected,the SRS system is energized
and monitoring the forward impact sensors and the safing sensor for
collision confirmation messages,When the vehicle strikes,or is
struck by,another object (such as a tree,wall,another vehicle,etc.),
the forward impact sensors and safing sensor send impulses to the
diagnostic module,which determines the force and direction of the
impact,Based on this information the diagnostic module either
deploys or does not deploy the air bag,Inflation happens when
there is a collision force equal to running into a brick wall at 10 to 15
miles per hour (16 to 24 km per hour),The airbag's inflation system
reacts sodium azide (NaN3) with potassium nitrate (KNO3) to
produce nitrogen gas (Fig.12-1),Hot blasts of the nitrogen inflate
the airbag.
System Components
Control Module
The air bag control module or SRS ECU is one of the most visible
part of the system,It contains the air bag safing sensor and
energy reserve capacitor,The module is mounted on the tunnel
floor pan forward of the center console,Some safing sensor is
located inside the control module,The safing sensor provides
confirmation of a crash,but does not determine the severity,
The control module monitors the system to determine the
system readiness,The control module will store a sufficient
energy to deploy the airbags for only two minutes after the
battery has been disconnected,The control module contains on-
board diagnostics,and will illuminate the AIR BAG warning lamp
on the dash when a fault has occurred,The warning equipment is
tested for a few seconds every time the vehicle is started,
Front Impact Sensors
By function,there are 2 types of front impact sensors,forward
impact sensors and safing sensors,
The forward sensors are located in various locations forward of
the passenger compartment,Some are located inside the fenders,
some are on the cowl,some are attached to the support in front
of the radiator.
Rear sensors are also known as safing sensors as their function
is to determine that a crash has occurred,Rear safing sensors are
located in various locations in the passenger compartment
depending on the manufacturer,Some are integrated with the
control/diagnostic module.
The rear safing sensor must close before the forward sensors to
avoid airbag deployment in cases where the impact is not severe
enough to cause deployment [1],When the vehicle is parked with
the ignition off deployment is very unlikely because there is no
power to the circuits for deployment,
The two front impact sensors provide verification of the direction
and severity of the impact,The impact sensors are threshold
sensitive switches that complete an electrical circuit when an
impact provides a sufficient inertia force to close the switch
(Fig.12-2),The sensors are calibrated for the specific vehicle and
react to the severity and direction of the impact,
Clock Spring
The clock spring is mounted on the steering column behind the
steering wheel and is used to maintain a continuous electrical circuit
between the wiring harness and the driver's air bag module,This
assembly consists of a flat ribbon-like electrically conductive tape
which winds and unwinds with the steering wheel rotation [2].
Air Bag Module
The driver air bag module is located on the steering wheel and is
the most visible part of the system,It contains the air bag cushion
and its supporting components,The module contains a housing to
which the cushion and inflator are attached and sealed.
The driver side inflator assembly is mounted from the back of the
module housing,When supplied with the proper electrical signal the
inflator assembly will produce a gas and discharge it directly into the
cushion,
A protective cover is fitted to the front of the driver air bag
module and forms a decorative cover in the center of the
steering wheel,The driver air bag module is mounted directly to
the steering wheel.
The passenger air bag module is located beneath the decorative
cover of the instrument panel,facing the passenger seat,The
passenger inflator is within the module housing,The module is
mounted to the upper and lower instrument panel,A protective
cover is fitted into the instrument panel over the way passenger
air bag module,This cover will pivot out of the way and allow the
cushion to fully inflate.
Airbag Deactivation
In response to concerns about children -- and others,especially
smaller people -- being killed or seriously injured by malfunctioning or
overly powerful airbags,the National Highway Traffic Safety
Administration (NHTSA) in 1997 issued a final rule to allow auto
manufacturers to use lower-powered airbags,This rule permits
airbags to be depowered by 20 to 35 percent,In addition,starting in
1998,repair shops and dealers were allowed to install on/off switches
that allow airbags to be deactivated.
Smart Systems
The smart airbag of the future is not just the airbag,but a redesign
of the components in the current airbag systems,Features include,
Weight Sensors This is a new sensor for the passenger seat to
classify the weight and to determine what type of occupant is in the
seat,adult or child,
Infrared Occupant Detection This system will use infra-red beams
(just like in your TV remote control) to detect the distance the
passenger is from the airbag and adapt the force of deployment
accordingly,
Capacitive Reflective Occupant Sensing These sensors will be
located in the seat backs and in the dash to identify the distance
you and or your passengers are from the dashboard,These
sensors will be able to discriminate between a human occupant
and inanimate objects like your groceries,This alone will save
thousands of dollars in the cases where the driver is the only
occupant in the front seat,
Updated Sensors The updated sensors will have the capabilities
of deploying the seatbelt pretensioners faster,so in a crash
situation you will be in the best position to benefit from the
airbag deployment,
Centralized Electronic Control Unit The new control units will be
able use all the input from the new sensor technology and thru
new software deploy what you need when you need it,
Service Precautions
When working on the SRS or any components which require
the removal of the air bag,adhere to all of these precautions to
minimize the risks of personal injury or component damage:
·Before attempting to diagnose,remove or install the air bag
system components,you must first disconnect and isolate the
negative (-) battery cable,Failure to do so could result in
accidental deployment and possible personal injury.
·When an undeployed air bag assembly is to be removed from
the steering wheel,after disconnecting the negative battery
cable,allow the system capacitor to discharge for two minutes
(Chrysler) before commencing with the air bag system
component removal.
·Replace the air bag system components only with specified
replacement parts,or equivalent.
Substitute parts may visually appear interchangeable,but
internal differences may result in inferior occupant protection.
·The fasteners,screws,and bolts originally used for the SRS
have special coatings and are specifically designed for the SRS,
They must never be replaced with any substitutes,Anytime a
new fastener is needed,replace with the correct fasteners
provided in the service package or fasteners listed in the parts
books.
Handling a Live Air Bag Module
At no time should any source of electricity be permitted near
the inflator on the back of the module [3],When carrying a
live module,the trim cover should be pointed away from the
body to minimize injury in the event of accidental deployment,
In addition,if the module is placed on a bench or other
surface,the plastic trim cover should be face up to minimize
movement in case of accidental deployment.
When handling a steering column with an air bag module
attached,never place the column on the floor or other
surface with the steering wheel or module face down,
Handling a Deployed Air Bag Module
The vehicle interior may contain a very small amount of
sodium hydroxide powder,a by-product of air bag
deployment,Since this powder can irritate the skin,eyes,
nose or throat,be sure to wear safety glasses,rubber gloves
and long sleeves during cleanup.
If you find that the cleanup is irritating your skin,run cool
water over the affected area,Also,if you experience nasal or
throat irritation,exit the vehicle for fresh air until the irritation
ceases,if irritation continues,see a physician.
Begin the cleanup by putting tape over the two air bag exhaust
vents so that no additional powder will find its way into the vehicle
interior,Then remove the air bag and air bag module from the
vehicle.
Use a vacuum cleaner to remove any residual powder from the
vehicle interior,Work from the outside in so that you avoid
kneeling or sitting in an uncleaned area,
Be sure to vacuum the heater and A/C outlets as well,In fact it's a
good idea to run the blower on low and to vacuum up any powder
expelled from the plenum,You may need to vacuum the interior of
the car a second time to recover all of the powder.
Check with the local authorities before disposing of the
deployed bag and module in your trash.
After an air bag has been deployed,the air bag module and
clock spring must be replaced because they cannot be reused,
Other air bag system components should be replaced with new
ones if damaged.
Disarming the System
CAUTION
The Supplemental Restraint System (SRS) system must be
disarmed before repair and/or removal of any component in its
immediate area including the air bag itself,Failure to do so may
cause accidental deployment of the air bag,resulting in
unnecessary SRS system repairs and/or personal injury.
1,Disconnect the negative battery cable and isolate the cable
using an appropriate insulator (wrap with quality electrical
tape).
Always wear safety goggles when working with,or around,
the air bag system.
2,Allow the system capacitor to discharge for 2 minutes
(CHRYSLER) before starting any repair on any air bag
system or related components,This will disable the air bag
system.
Arming the System
To arm the SRS,reconnect the negative battery cable,This
will automatically enable the air bag system.
小结
System Operation
System Components
Airbag Deactivation
Smart Systems
Service Precautions
Handling a Live Air Bag Module
Handling a Deployed Air Bag Module
Disarming the System
Arming the System
作业
熟记相关专业词汇
P270 EXERCIES Ⅰ &Ⅱ
