UNIT 13
AUTOMOTIVE COMPUTERS AND
COMMUNICATION SYSTEM
TEXT A
Computers on Modern Vehicles
PROFESSIONAL ENGLISH
TEXT A
Computers on Modern Vehicles
Computers
Central Processing Unit
Temporary Computer Memory
Permanent Computer Memory
Computer Control Operation
Open and Closed Loop Operation
Input Sensors
Output Devices
本次课学习内容本次课学习目标
掌握 automotive computer的英文专业词汇
训练快速阅读能力，提高阅读速度
NEW WORDS
defective [di'fektiv] a.有缺陷的,损坏的，有故障的
affix [?'fiks] v.使附于,粘贴，使固定
revise [ri'vaiz] v.修订,修正,修改
nonvolatile ['n?n'v?l?tail] a.非易失性的
ultraviolet ['?ltr?'vai?lit] a.紫外线的,紫外的
random ['r?nd?m] a.任意的,随机的 ; n.随意,任意
volatile ['v?l?tail] a.可变的,易失的，不稳定的
fuel mileage 燃油经济性
burn in 烧上，烙上，腐蚀，留下不可磨灭的印象
volatile memory 遗失存储器
keep alive memory
(KAM)
可保持存储器 (KAM)
read only memory
(ROM)
只读存储器 (ROM)
programmable read
only memory (PROM)
可编程只读存储器 (PROM)
erasable programmable
read only
memory(EPROM)
可擦可编程只读存储器 (EPROM)
electronically erasable
programmable read
only memory
(EEPROM)
电可擦可编程只读存储器
(EEPROM)
over and over 反复
in nature 本质上，实际上
Computers on Modern Vehicles
Almost every vehicle built in the last 10-15 years has at
least one on-board computer,There may be up to six
different computers on some vehicles,On-board computers
control ignition and fuel systems,emission controls,cooling
fans,air conditioner compressor,torque converter clutch,
and transmission shift points.
Other vehicle computers control the air bags,anti-lock
brake and traction control systems,interior air temperature
and distribution,suspension and steering systems,and the
anti-theft system,Many modern vehicles combine the
engine contro1 computer and other vehicle computers into
one large microprocessor,which monitors and controls
most vehicle functions.
The primary reason for using on-board computers in modern
vehicles is to meet fuel economy and emissions regulations,
The use of computers allows the ignition,fuel,and emission
systems operations to be controlled precisely,The end result is
a stoichiometric air-fuel ratio that is as close to 14.7:1 as
possible,
This air-fuel ratio is necessary for optimum catalytic
converter operation as well as good fuel economy and
emissions performance,Newer on-board computers also
control the torque converter clutch,transmission shift points,
and air conditioner operation to increase fuel mileage as well
as lower emissions,The computer control system can be
divided into three major subsystems,computer,input sensors
and output devices.
Computers
A vehicle's on-board computer is normally referred to as an
electronic control unit or ECU,The ECU has many different
names,A vehicle's ECU may be referred to by one of the
following terms:
·controller
·microprocessor
·on-board computer
·engine control computer (ECC)
·engine or electronic control module (ECM)
·powertrain control module (PCM)
These names are the most common and depending on the
manufacturer and vehicle system [1],other specific names may
be used,ECU's are usually contained in one casing,Most ECU's
are located inside the vehicle's interior away from the heat and
vibration of the engine compartment,but can be located
almost anywhere depending on the vehicle,system,and
manufacturer,
A few ECUs are made in two parts,with the processor located
in the passenger compartment and the output part under the
hood,Whatever their physical locations,all ECUs contain two
main sections,the central processing unit and the memory section,
The memory section has two separate sections of memory--
permanent and temporary.
Central Processing Unit
The central processing unit (CPU) is the section of the electronic
control unit that performs calculations and makes decisions,The
CPU is sometimes called the controller,The CPU is constructed
using one or more integrated circuits,or ICs,Incoming data from
the input sensors must go through the CPU,where the data is
processed and adjustments made to the output sensors,The ECU
must be replaced if the CPU is defective,as it is affixed to the
ECU's circuit board.
Permanent Computer Memory
There are four basic types of permanent computer memory,read
only memory (ROM),programmable read only memory (PROM),
erasable programmable read only memory (EPROM),and
electronically erasable programmable read only memory (EEPROM),
A program that tells the ECU what to do and when to do it is stored
in ROM,The ROM also contains general information that is used as a
standard of operation under various conditions,Once this
information is placed in memory,it cannot be modified,The ROM is
an integral part of the ECU,If the ROM is defective,the ECU must
be replaced.
Programmable read only memory (PROM) is a variation of ROM,
On some vehicles,the PROM is plugged into the ECU and can be
replaced if it is defective or if a revised PROM is needed,This
eliminates the expense of replacing the entire ECU,On most newer
vehicles,the PROM is permanently affixed to the ECU,The ROM and
PROM are nonvolatile memories,This means that information stored
in these memories will remain even if the battery is disconnected.
The EPROM can be reprogrammed by exposing it to ultraviolet
light and then reprogramming it,This can only be done by the
manufacturer,The EEPROM can be erased electronically and
reprogrammed or "burned in",using either electronic scan tools or
computerized diagnostic equipment.
Temporary Computer Memory
The ECU uses random access memory (RAM) as a temporary
storage place for data from the sensors,As new information is
received from the sensors,it is written over the old information
inside the RAM,The ECU constantly receives new signals from the
sensors while the engine is running,If no signal or the wrong signal
is received by the ECU,a diagnostic trouble code is stored in the
RAM.
The RAM is contained inside the ECU,If the RAM is defective,the
ECU must be replaced,The RAM has a volatile memory,This means
that if the battery,fuse,or the power source at the ECU is
disconnected,all data in the RAM will be erased,including any
stored trouble codes,Some ECUs use another type of memory called
keep alive memory (KAM).
KAM is a memory chip that allows the ECU to maintain
normal vehicle performance by compensating for sensor and
parts wear,This is sometimes called an adaptive strategy,Any
data in KAM is also lost if power to the ECU is disconnected.
Computer Control Operation
Although it is far simpler,the computer control system
operates in much the same way as the human nervous system,
If you touch a hot engine part,the nerves in your hand send a
signal to your brain,Based on the signal,your brain decides
that your hand may get burned and tells your arm muscles to
pull your hand away from the part.
An ECU receives input data in the form of electrical signals
from the sensors (nerves),The ECU (brain) compares the
input data to the standards in the ROM,Based on its
calculations,the ECU sends commands to the output devices
(arm muscles),This process is performed over and over as
engine,environmental,and vehicle conditions change.
Open and Closed Loop Operation
When the engine is cold,it cannot provide optimum fuel
economy and emissions control,Also,several of the input
sensors must warm up to operating temperature before they can
provide reliable readings,Therefore,while one or more of the
input sensors tells the ECU that the engine is below a certain
temperature,the ECU operates in open loop mode,In open loop
mode,the ECU controls the air-fuel ratio based on preset
information while monitoring the input sensor readings,Some
computer control systems also go into open loop mode when the
throttle is opened completely,often called wide open throttle
mode.
When the input sensors tell the ECU that the engine has
warmed up sufficiently,the ECU goes into closed loop mode,In
the closed loop mode,the ECU begins processing the information
from the input sensors and bases its commands to the output
devices on the sensor information,The result is optimum fuel
economy and engine performance with minimal emissions output.
Input Sensors
The electronic control unit receives hundreds of input signals
every second,These signals are created by input sensors,
Each sensor measures one operating condition of the engine
or drive train,The sensor then sends an electrical signal that
represents the measurement to the ECU,Some sensors
produce their own voltage signal and other sensors adjust the
voltage sent to it by the ECU,The voltage sent to these
sensors by the ECU is called the reference voltage.
The amount of resistance at the sensor determines how
much output voltage is sent to the ECU,The ECU then
compares its reference voltage to the sensor output voltage,
This determines the sensor measurement,Some inputs to the
ECU are electrical in nature and do not require a separate
sensor to operate them,Examples are the charging system
voltage,and voltage to apply the air conditioner clutch.
Output Devices
An electrical unit controlled by the ECU is called an output
device,Output devices control the fuel,ignition,emission
control,and other parts of the vehicle,Output devices can be
solenoids,relays,electric motors,or other electronic devices.
Examples of output devices are the idle speed motor or solenoid,
mixture control solenoid,fuel injector,ignition coil,ignition
module,EGR system,air injection system,fuel pump relay,and
electric fan motor relay.
小结
Computers on Modern Vehicles
Computers
Central Processing Unit
Temporary Computer Memory
Permanent Computer Memory
Computer Control Operation
Open and Closed Loop Operation
Input Sensors
Output Devices
作业
熟记相关专业词汇
P287 EXERCIES Ⅰ &Ⅱ
AUTOMOTIVE COMPUTERS AND
COMMUNICATION SYSTEM
TEXT A
Computers on Modern Vehicles
PROFESSIONAL ENGLISH
TEXT A
Computers on Modern Vehicles
Computers
Central Processing Unit
Temporary Computer Memory
Permanent Computer Memory
Computer Control Operation
Open and Closed Loop Operation
Input Sensors
Output Devices
本次课学习内容本次课学习目标
掌握 automotive computer的英文专业词汇
训练快速阅读能力，提高阅读速度
NEW WORDS
defective [di'fektiv] a.有缺陷的,损坏的，有故障的
affix [?'fiks] v.使附于,粘贴，使固定
revise [ri'vaiz] v.修订,修正,修改
nonvolatile ['n?n'v?l?tail] a.非易失性的
ultraviolet ['?ltr?'vai?lit] a.紫外线的,紫外的
random ['r?nd?m] a.任意的,随机的 ; n.随意,任意
volatile ['v?l?tail] a.可变的,易失的，不稳定的
fuel mileage 燃油经济性
burn in 烧上，烙上，腐蚀，留下不可磨灭的印象
volatile memory 遗失存储器
keep alive memory
(KAM)
可保持存储器 (KAM)
read only memory
(ROM)
只读存储器 (ROM)
programmable read
only memory (PROM)
可编程只读存储器 (PROM)
erasable programmable
read only
memory(EPROM)
可擦可编程只读存储器 (EPROM)
electronically erasable
programmable read
only memory
(EEPROM)
电可擦可编程只读存储器
(EEPROM)
over and over 反复
in nature 本质上，实际上
Computers on Modern Vehicles
Almost every vehicle built in the last 10-15 years has at
least one on-board computer,There may be up to six
different computers on some vehicles,On-board computers
control ignition and fuel systems,emission controls,cooling
fans,air conditioner compressor,torque converter clutch,
and transmission shift points.
Other vehicle computers control the air bags,anti-lock
brake and traction control systems,interior air temperature
and distribution,suspension and steering systems,and the
anti-theft system,Many modern vehicles combine the
engine contro1 computer and other vehicle computers into
one large microprocessor,which monitors and controls
most vehicle functions.
The primary reason for using on-board computers in modern
vehicles is to meet fuel economy and emissions regulations,
The use of computers allows the ignition,fuel,and emission
systems operations to be controlled precisely,The end result is
a stoichiometric air-fuel ratio that is as close to 14.7:1 as
possible,
This air-fuel ratio is necessary for optimum catalytic
converter operation as well as good fuel economy and
emissions performance,Newer on-board computers also
control the torque converter clutch,transmission shift points,
and air conditioner operation to increase fuel mileage as well
as lower emissions,The computer control system can be
divided into three major subsystems,computer,input sensors
and output devices.
Computers
A vehicle's on-board computer is normally referred to as an
electronic control unit or ECU,The ECU has many different
names,A vehicle's ECU may be referred to by one of the
following terms:
·controller
·microprocessor
·on-board computer
·engine control computer (ECC)
·engine or electronic control module (ECM)
·powertrain control module (PCM)
These names are the most common and depending on the
manufacturer and vehicle system [1],other specific names may
be used,ECU's are usually contained in one casing,Most ECU's
are located inside the vehicle's interior away from the heat and
vibration of the engine compartment,but can be located
almost anywhere depending on the vehicle,system,and
manufacturer,
A few ECUs are made in two parts,with the processor located
in the passenger compartment and the output part under the
hood,Whatever their physical locations,all ECUs contain two
main sections,the central processing unit and the memory section,
The memory section has two separate sections of memory--
permanent and temporary.
Central Processing Unit
The central processing unit (CPU) is the section of the electronic
control unit that performs calculations and makes decisions,The
CPU is sometimes called the controller,The CPU is constructed
using one or more integrated circuits,or ICs,Incoming data from
the input sensors must go through the CPU,where the data is
processed and adjustments made to the output sensors,The ECU
must be replaced if the CPU is defective,as it is affixed to the
ECU's circuit board.
Permanent Computer Memory
There are four basic types of permanent computer memory,read
only memory (ROM),programmable read only memory (PROM),
erasable programmable read only memory (EPROM),and
electronically erasable programmable read only memory (EEPROM),
A program that tells the ECU what to do and when to do it is stored
in ROM,The ROM also contains general information that is used as a
standard of operation under various conditions,Once this
information is placed in memory,it cannot be modified,The ROM is
an integral part of the ECU,If the ROM is defective,the ECU must
be replaced.
Programmable read only memory (PROM) is a variation of ROM,
On some vehicles,the PROM is plugged into the ECU and can be
replaced if it is defective or if a revised PROM is needed,This
eliminates the expense of replacing the entire ECU,On most newer
vehicles,the PROM is permanently affixed to the ECU,The ROM and
PROM are nonvolatile memories,This means that information stored
in these memories will remain even if the battery is disconnected.
The EPROM can be reprogrammed by exposing it to ultraviolet
light and then reprogramming it,This can only be done by the
manufacturer,The EEPROM can be erased electronically and
reprogrammed or "burned in",using either electronic scan tools or
computerized diagnostic equipment.
Temporary Computer Memory
The ECU uses random access memory (RAM) as a temporary
storage place for data from the sensors,As new information is
received from the sensors,it is written over the old information
inside the RAM,The ECU constantly receives new signals from the
sensors while the engine is running,If no signal or the wrong signal
is received by the ECU,a diagnostic trouble code is stored in the
RAM.
The RAM is contained inside the ECU,If the RAM is defective,the
ECU must be replaced,The RAM has a volatile memory,This means
that if the battery,fuse,or the power source at the ECU is
disconnected,all data in the RAM will be erased,including any
stored trouble codes,Some ECUs use another type of memory called
keep alive memory (KAM).
KAM is a memory chip that allows the ECU to maintain
normal vehicle performance by compensating for sensor and
parts wear,This is sometimes called an adaptive strategy,Any
data in KAM is also lost if power to the ECU is disconnected.
Computer Control Operation
Although it is far simpler,the computer control system
operates in much the same way as the human nervous system,
If you touch a hot engine part,the nerves in your hand send a
signal to your brain,Based on the signal,your brain decides
that your hand may get burned and tells your arm muscles to
pull your hand away from the part.
An ECU receives input data in the form of electrical signals
from the sensors (nerves),The ECU (brain) compares the
input data to the standards in the ROM,Based on its
calculations,the ECU sends commands to the output devices
(arm muscles),This process is performed over and over as
engine,environmental,and vehicle conditions change.
Open and Closed Loop Operation
When the engine is cold,it cannot provide optimum fuel
economy and emissions control,Also,several of the input
sensors must warm up to operating temperature before they can
provide reliable readings,Therefore,while one or more of the
input sensors tells the ECU that the engine is below a certain
temperature,the ECU operates in open loop mode,In open loop
mode,the ECU controls the air-fuel ratio based on preset
information while monitoring the input sensor readings,Some
computer control systems also go into open loop mode when the
throttle is opened completely,often called wide open throttle
mode.
When the input sensors tell the ECU that the engine has
warmed up sufficiently,the ECU goes into closed loop mode,In
the closed loop mode,the ECU begins processing the information
from the input sensors and bases its commands to the output
devices on the sensor information,The result is optimum fuel
economy and engine performance with minimal emissions output.
Input Sensors
The electronic control unit receives hundreds of input signals
every second,These signals are created by input sensors,
Each sensor measures one operating condition of the engine
or drive train,The sensor then sends an electrical signal that
represents the measurement to the ECU,Some sensors
produce their own voltage signal and other sensors adjust the
voltage sent to it by the ECU,The voltage sent to these
sensors by the ECU is called the reference voltage.
The amount of resistance at the sensor determines how
much output voltage is sent to the ECU,The ECU then
compares its reference voltage to the sensor output voltage,
This determines the sensor measurement,Some inputs to the
ECU are electrical in nature and do not require a separate
sensor to operate them,Examples are the charging system
voltage,and voltage to apply the air conditioner clutch.
Output Devices
An electrical unit controlled by the ECU is called an output
device,Output devices control the fuel,ignition,emission
control,and other parts of the vehicle,Output devices can be
solenoids,relays,electric motors,or other electronic devices.
Examples of output devices are the idle speed motor or solenoid,
mixture control solenoid,fuel injector,ignition coil,ignition
module,EGR system,air injection system,fuel pump relay,and
electric fan motor relay.
小结
Computers on Modern Vehicles
Computers
Central Processing Unit
Temporary Computer Memory
Permanent Computer Memory
Computer Control Operation
Open and Closed Loop Operation
Input Sensors
Output Devices
作业
熟记相关专业词汇
P287 EXERCIES Ⅰ &Ⅱ
