UNIT 3
FUEL INJECTION SYSTEMS
TEXT A
Electronic Fuel Injection Systems
PROFESSIONAL ENGLISH
UNIT 3
FUEL INJECTION SYSTEMS
TEXT A
Electronic Fuel Injection Systems
Pulse Fuel Injection
Pulse Fuel Injection System Components
Air induction system
Fuel delivery system
Engine control computer
Electronic Sensors
Continuous Injection Systems (CIS)
本次课学习内容本次课学习目标
掌握电控燃油喷射系统主要部件的英文名称、主要部件的作用及工作原理
掌握常用术语（ phrases and
expressions）
了解相关术语（ related terms）
提高翻译能力
NEW WORDS
manifold ['m?nifould] n.歧管
manipulate [m?'nipjuleit] v.操纵，控制，支配
venturi [ven'tu:ri] n.文丘里管，喉管
driveability [draiv?'biliti] n.运行性能，操纵性能
lag [l?g] n.滞后，迟后，惯性，惰性
turbocharger ['t?:bout∫ɑ:] n.涡轮增压器，增压器
compressor [k?m'pres?] n.压气机，压缩机，压缩装置
sensor ['sens?] n.传感器
passageway ['p?si?wei] n.通路
psi ( = pound per square inch ) 磅力 /平方英寸（ lbf/in2）
injector [in'?ekt?] n.喷油器，注射器
circuit ['s?:kit] n.电（气，油，回）路
complexity [k?m'pleksiti] n.复杂性
plug [pl?g] n.塞子，堵头，插头
energize ['enaiz] v.通电，励磁
distributor [di'stribjut?] n.分配器，分电器
throttle ['θr?tl] n.节气门
relay ['rilei,'ri:'lei] n.继电器，转播； v.中继，转播
barometric [b?rou'metrik] n.大气压力的
vortex ['v?:teks] n.涡流，涡旋，旋风
distinctly [dis'ti?ktli] ad.显然，清楚地，明明
spawn [sp?:n] v.产卵
pulse fuel injection 脉冲燃油喷射
continuous fuel injection 连续燃油喷射
throttle body injection 节气门体喷射
single-point injection 单点喷射
central fuel injection 中央喷射
multi-point systems 多点喷射
multi-port injection 多点喷射
tuned intake runners 调谐进气管
intake manifold 进气歧管
air induction system 进气系统
PHRASES AND EXPRESSIONS
fuel delivery system 供油系统
air cleaner 空气滤清器
electric fuel pump 电动燃油泵
pressure regulator 压力调节器
fuel inlet line 进油管
fuel tank 燃油箱
fuel injector 喷油器
fuel rail 燃油分配管，油轨
ignition coil 点火线圈
Hall-effect switch 霍尔效应开关
barometric pressure 大气压力
heated wire热线式
air valve空气阀式（ =vane type叶片式）
Karmann vortex 卡曼涡旋式
Electronic Fuel Injection
Fuel injection systems deliver fuel by forcing it into the
incoming air stream（ Fig.3-1）,Fuel injection systems
actually measure the incoming air and pressurize the fuel to
deliver it in precise amounts based directly on that
measurement,Because fuel is delivered to the manifold
under pressure,the quantity of fuel delivered can be more
positively controlled,With this more positive control,fuel
delivery can be more easily manipulated to meet the unique
demands of extreme operating conditions,This results in
greater efficiency over a wider range of operation.
In the electronic injection system,the air-fuel mixture is
controlled in one of two ways,The injector may be opened
and closed by electrical signals,This is a pulse fuel
injection system,In the other type of system,the injector is
forced open by fuel pressure,Fuel pressure is controlled by
an electronic control device,or by an airflow metering valve,
depending on the system,This is the continuous fuel
injection system.
Fig,3-1 Fuel injector is mounted on the intake manifold
1,Pulse Fuel Injection
In pulse injection systems,the rate of fuel flow through the
injectors remains constant,The total amount of fuel delivered is
determined by the length of time the injectors are held open,
Systems are classified by the type of timing sequence used and
the location of the injectors.
Types of Pulse Fuel Injection Systems
The next section will discuss common fuel injection systems
which are typical of the pulse systems now in use,The pulse
injection system is usually electronically controlled,Although
there are a number of design differences between various pulse
fuel injection systems,the operating principles are very similar.
The throttle body injection system uses an assembly containing
one or two fuel injectors,The assembly is mounted at the
entrance to the intake manifold and injects fuel ahead of the
throttle valve,These systems are also called single-point
injection or central fuel injection,
Multi-point systems,also called multi-port injection systems,
deliver fuel at the engine intake ports near the intake valves,
This means that the intake manifold delivers only air,in contrast
to carburetors or single-point fuel injection systems in which the
intake manifold carries the air-fuel mixture [1],As a result,these
systems offer the following advantages:
·greater power by avoiding venturi losses as in a carburetor,
and by allowing the use of tuned intake runners for better torque
characteristics
·improved driveability by reducing the throttle-change lag
which occurs while the fuel travels from the throttle body to the
intake ports [2]
·increased fuel economy by avoiding condensation of fuel on
interior walls of the intake manifold (manifold wetting)
·simplified turbocharger applications; the turbocharger
compressor need only handle air.
Pulse Fuel Injection System Components
The typical pulse system can be broken into three basic
parts:
·Air induction system.
·Fuel delivery system.
·Electronic control system(including engine control computer
and electronic sensors).
Air induction system
The air induction system consists of an air cleaner assembly,
throttle body,and intake manifold,The throttle body section
contains the throttle valve,which is opened and closed by the
driver to control the amount of air entering the intake manifold.
On throttle body fuel injection systems,the throttle body also
contains the fuel injection components as discussed earlier,
The intake manifold forms a closed passageway between the
throttle body and the cylinder head,
Fig.3-2 Fuel delivery system
Fuel delivery system
The fuel delivery system（ Fig.3-2） provides the fuel which
mixes with the air,Pressure is provided by an electric fuel pump,
Some systems use two pumps,a low-pressure fuel pump that
delivers fuel to another pump,which develops the pressure.
Fuel Pressure Regulators
Pressure in some throttle body fuel injection systems is as
low as 7 psi,while some multi-port systems can reach 60 psi
(55 kPa to 380 kPa) or more,Injection system pressure is
controlled by a pressure regulator,The regulator controls
pressure by bleeding excess fuel back into the fuel inlet line
or the fuel tank,Pressure regulators on multi-port fuel
injection systems are usually connected by a hose to the
intake manifold.
Fuel Injectors
The fuel injectors receive fuel from the pump or pumps
and pressure regulator and spray it into the intake manifold,
Injectors can be part of a throttle body,or installed in the
intake manifold and connected to the fuel system through a
fuel rail,The fuel rail is a rigid piece of steel tubing that feeds
fuel to the injectors,Some systems use flexible hoses to
connect the injectors to the fuel rail.
Engine control computer
Engine control computers are constructed using many
different electronic circuits and components,Size and
complexity varies depending upon the system,Modern
computers control many other engine systems in addition
to the fuel injectors,The computer is usually located in a
protected area away from engine vibration and heat,and is
connected to the rest of the injection system by means of a
sealed wiring harness plug.
The computer receives signals from a number of sensors
whenever the engine is running,From this input,the
computer evaluates engine fuel needs and adjusts injector
pulse width accordingly,Some computers also energize the
fuel pump or pumps for 2-5 seconds to pressurize the fuel
system before a cold start,Many fuel injection systems do
this in place of a cold start valve.
Electronic Sensors
The electronic sensors monitor (check) various
engine functions and feed this information to the
computer,The number and types of sensors vary with
the system,
Oxygen Sensor
The oxygen sensor monitors the amount of oxygen
in the engine's exhaust gases,As the oxygen content
in the exhaust gases changes,the voltage signal
produced by the sensor also changes,The computer
uses signals from the oxygen sensor to control the
air-fuel mixture,The oxygen sensor is generally
mounted in the exhaust manifold,Most electronic fuel
injection systems rely on this sensor for much of the
engine's operating information.
Engine Speed Sensor
The engine speed sensor monitors engine RPM,Many speed
sensors are mounted in the distributor,where they obtain a
signal from the rotating distributor shaft,In some cases,the
ignition coil or Hall-effect switch provides the signal to the
computer,In other systems,the speed sensor is mounted so
that it can monitor crankshaft or camshaft rotation.
These speed sensors also indicate the crankshaft and
camshaft position so that the computer can open the injector
before the intake valve opens,This information is utilized by the
computer (along with other sensor inputs) to help determine
injector pulse timing and pulse width.
Throttle Position Sensor
Throttle position is relayed to the computer by the throttle
position sensor,Throttle position sensors are installed on the
throttle body,and are used to monitor the movement of the
throttle valve,They can be resistance types,Resistance
sensors contain variable resistance units which send a varying
signal to the computer,depending on throttle position.
Manifold Absolute Pressure Sensor
Engine load is transmitted to the computer by means of an
intake manifold absolute pressure sensor,The sensor converts
manifold vacuum into a small electrical signal,This input allows
the computer to increase fuel supply when the engine is under
load and needs a richer mixture,and decrease fuel supply when
engine load is light.
Barometric Pressure Sensor
Many injection systems have a sensor to measure the
pressure of the outside air,usually called atmospheric or
barometric pressure,Barometric pressure is compared with
manifold vacuum by the computer to more closely monitor
engine load,The input of this sensor is important when the
vehicle is driven to higher and lower altitudes,This sensor is
sometimes combined with the manifold vacuum sensor into a
single unit.
Temperature Sensor
Temperature has a great effect on the operation of the fuel
injection system,To overcome the tendency of cold fuel to
condense into an noncombustible liquid,cold engines must
have a richer mixture if they are to run properly,Every
injection system has a temperature sensor to measure
engine coolant temperature,Many injection systems have an
additional sensor to measure the temperature of the
incoming air.
Airflow Sensor
Some late model fuel injection systems monitor the
amount of air entering the engine by using an airflow sensor,
The computer takes this input and compares it with engine
RPM and manifold vacuum to determine the amount of fuel
to inject,There are three types of airflow sensors,the heated
wire,the air valve and the Karmann vortex.
2,Continuous Injection Systems (CIS)
The continuous systems are sometimes referred to as
mechanical or hydro-mechanical,because fuel metering is
determined by the mechanical relationship between an air-
flow sensor and a fuel distributor.
The first continuous systems were distinctly different
from EFI systems,since there was no electronic control of
basic fuel delivery,The continuous injection family has now
grown and spawned more highly developed versions,and
electronic control has been a part of almost all CIS fuel
injection since 1980.
小结
Pulse Fuel Injection
Pulse Fuel Injection System Components
Air induction system
Fuel delivery system
Engine control computer
Electronic Sensors
Continuous Injection Systems (CIS)
作业
熟记相关专业词汇
P60 EXERCIES Ⅰ & Ⅱ
FUEL INJECTION SYSTEMS
TEXT A
Electronic Fuel Injection Systems
PROFESSIONAL ENGLISH
UNIT 3
FUEL INJECTION SYSTEMS
TEXT A
Electronic Fuel Injection Systems
Pulse Fuel Injection
Pulse Fuel Injection System Components
Air induction system
Fuel delivery system
Engine control computer
Electronic Sensors
Continuous Injection Systems (CIS)
本次课学习内容本次课学习目标
掌握电控燃油喷射系统主要部件的英文名称、主要部件的作用及工作原理
掌握常用术语（ phrases and
expressions）
了解相关术语（ related terms）
提高翻译能力
NEW WORDS
manifold ['m?nifould] n.歧管
manipulate [m?'nipjuleit] v.操纵，控制，支配
venturi [ven'tu:ri] n.文丘里管，喉管
driveability [draiv?'biliti] n.运行性能，操纵性能
lag [l?g] n.滞后，迟后，惯性，惰性
turbocharger ['t?:bout∫ɑ:] n.涡轮增压器，增压器
compressor [k?m'pres?] n.压气机，压缩机，压缩装置
sensor ['sens?] n.传感器
passageway ['p?si?wei] n.通路
psi ( = pound per square inch ) 磅力 /平方英寸（ lbf/in2）
injector [in'?ekt?] n.喷油器，注射器
circuit ['s?:kit] n.电（气，油，回）路
complexity [k?m'pleksiti] n.复杂性
plug [pl?g] n.塞子，堵头，插头
energize ['enaiz] v.通电，励磁
distributor [di'stribjut?] n.分配器，分电器
throttle ['θr?tl] n.节气门
relay ['rilei,'ri:'lei] n.继电器，转播； v.中继，转播
barometric [b?rou'metrik] n.大气压力的
vortex ['v?:teks] n.涡流，涡旋，旋风
distinctly [dis'ti?ktli] ad.显然，清楚地，明明
spawn [sp?:n] v.产卵
pulse fuel injection 脉冲燃油喷射
continuous fuel injection 连续燃油喷射
throttle body injection 节气门体喷射
single-point injection 单点喷射
central fuel injection 中央喷射
multi-point systems 多点喷射
multi-port injection 多点喷射
tuned intake runners 调谐进气管
intake manifold 进气歧管
air induction system 进气系统
PHRASES AND EXPRESSIONS
fuel delivery system 供油系统
air cleaner 空气滤清器
electric fuel pump 电动燃油泵
pressure regulator 压力调节器
fuel inlet line 进油管
fuel tank 燃油箱
fuel injector 喷油器
fuel rail 燃油分配管，油轨
ignition coil 点火线圈
Hall-effect switch 霍尔效应开关
barometric pressure 大气压力
heated wire热线式
air valve空气阀式（ =vane type叶片式）
Karmann vortex 卡曼涡旋式
Electronic Fuel Injection
Fuel injection systems deliver fuel by forcing it into the
incoming air stream（ Fig.3-1）,Fuel injection systems
actually measure the incoming air and pressurize the fuel to
deliver it in precise amounts based directly on that
measurement,Because fuel is delivered to the manifold
under pressure,the quantity of fuel delivered can be more
positively controlled,With this more positive control,fuel
delivery can be more easily manipulated to meet the unique
demands of extreme operating conditions,This results in
greater efficiency over a wider range of operation.
In the electronic injection system,the air-fuel mixture is
controlled in one of two ways,The injector may be opened
and closed by electrical signals,This is a pulse fuel
injection system,In the other type of system,the injector is
forced open by fuel pressure,Fuel pressure is controlled by
an electronic control device,or by an airflow metering valve,
depending on the system,This is the continuous fuel
injection system.
Fig,3-1 Fuel injector is mounted on the intake manifold
1,Pulse Fuel Injection
In pulse injection systems,the rate of fuel flow through the
injectors remains constant,The total amount of fuel delivered is
determined by the length of time the injectors are held open,
Systems are classified by the type of timing sequence used and
the location of the injectors.
Types of Pulse Fuel Injection Systems
The next section will discuss common fuel injection systems
which are typical of the pulse systems now in use,The pulse
injection system is usually electronically controlled,Although
there are a number of design differences between various pulse
fuel injection systems,the operating principles are very similar.
The throttle body injection system uses an assembly containing
one or two fuel injectors,The assembly is mounted at the
entrance to the intake manifold and injects fuel ahead of the
throttle valve,These systems are also called single-point
injection or central fuel injection,
Multi-point systems,also called multi-port injection systems,
deliver fuel at the engine intake ports near the intake valves,
This means that the intake manifold delivers only air,in contrast
to carburetors or single-point fuel injection systems in which the
intake manifold carries the air-fuel mixture [1],As a result,these
systems offer the following advantages:
·greater power by avoiding venturi losses as in a carburetor,
and by allowing the use of tuned intake runners for better torque
characteristics
·improved driveability by reducing the throttle-change lag
which occurs while the fuel travels from the throttle body to the
intake ports [2]
·increased fuel economy by avoiding condensation of fuel on
interior walls of the intake manifold (manifold wetting)
·simplified turbocharger applications; the turbocharger
compressor need only handle air.
Pulse Fuel Injection System Components
The typical pulse system can be broken into three basic
parts:
·Air induction system.
·Fuel delivery system.
·Electronic control system(including engine control computer
and electronic sensors).
Air induction system
The air induction system consists of an air cleaner assembly,
throttle body,and intake manifold,The throttle body section
contains the throttle valve,which is opened and closed by the
driver to control the amount of air entering the intake manifold.
On throttle body fuel injection systems,the throttle body also
contains the fuel injection components as discussed earlier,
The intake manifold forms a closed passageway between the
throttle body and the cylinder head,
Fig.3-2 Fuel delivery system
Fuel delivery system
The fuel delivery system（ Fig.3-2） provides the fuel which
mixes with the air,Pressure is provided by an electric fuel pump,
Some systems use two pumps,a low-pressure fuel pump that
delivers fuel to another pump,which develops the pressure.
Fuel Pressure Regulators
Pressure in some throttle body fuel injection systems is as
low as 7 psi,while some multi-port systems can reach 60 psi
(55 kPa to 380 kPa) or more,Injection system pressure is
controlled by a pressure regulator,The regulator controls
pressure by bleeding excess fuel back into the fuel inlet line
or the fuel tank,Pressure regulators on multi-port fuel
injection systems are usually connected by a hose to the
intake manifold.
Fuel Injectors
The fuel injectors receive fuel from the pump or pumps
and pressure regulator and spray it into the intake manifold,
Injectors can be part of a throttle body,or installed in the
intake manifold and connected to the fuel system through a
fuel rail,The fuel rail is a rigid piece of steel tubing that feeds
fuel to the injectors,Some systems use flexible hoses to
connect the injectors to the fuel rail.
Engine control computer
Engine control computers are constructed using many
different electronic circuits and components,Size and
complexity varies depending upon the system,Modern
computers control many other engine systems in addition
to the fuel injectors,The computer is usually located in a
protected area away from engine vibration and heat,and is
connected to the rest of the injection system by means of a
sealed wiring harness plug.
The computer receives signals from a number of sensors
whenever the engine is running,From this input,the
computer evaluates engine fuel needs and adjusts injector
pulse width accordingly,Some computers also energize the
fuel pump or pumps for 2-5 seconds to pressurize the fuel
system before a cold start,Many fuel injection systems do
this in place of a cold start valve.
Electronic Sensors
The electronic sensors monitor (check) various
engine functions and feed this information to the
computer,The number and types of sensors vary with
the system,
Oxygen Sensor
The oxygen sensor monitors the amount of oxygen
in the engine's exhaust gases,As the oxygen content
in the exhaust gases changes,the voltage signal
produced by the sensor also changes,The computer
uses signals from the oxygen sensor to control the
air-fuel mixture,The oxygen sensor is generally
mounted in the exhaust manifold,Most electronic fuel
injection systems rely on this sensor for much of the
engine's operating information.
Engine Speed Sensor
The engine speed sensor monitors engine RPM,Many speed
sensors are mounted in the distributor,where they obtain a
signal from the rotating distributor shaft,In some cases,the
ignition coil or Hall-effect switch provides the signal to the
computer,In other systems,the speed sensor is mounted so
that it can monitor crankshaft or camshaft rotation.
These speed sensors also indicate the crankshaft and
camshaft position so that the computer can open the injector
before the intake valve opens,This information is utilized by the
computer (along with other sensor inputs) to help determine
injector pulse timing and pulse width.
Throttle Position Sensor
Throttle position is relayed to the computer by the throttle
position sensor,Throttle position sensors are installed on the
throttle body,and are used to monitor the movement of the
throttle valve,They can be resistance types,Resistance
sensors contain variable resistance units which send a varying
signal to the computer,depending on throttle position.
Manifold Absolute Pressure Sensor
Engine load is transmitted to the computer by means of an
intake manifold absolute pressure sensor,The sensor converts
manifold vacuum into a small electrical signal,This input allows
the computer to increase fuel supply when the engine is under
load and needs a richer mixture,and decrease fuel supply when
engine load is light.
Barometric Pressure Sensor
Many injection systems have a sensor to measure the
pressure of the outside air,usually called atmospheric or
barometric pressure,Barometric pressure is compared with
manifold vacuum by the computer to more closely monitor
engine load,The input of this sensor is important when the
vehicle is driven to higher and lower altitudes,This sensor is
sometimes combined with the manifold vacuum sensor into a
single unit.
Temperature Sensor
Temperature has a great effect on the operation of the fuel
injection system,To overcome the tendency of cold fuel to
condense into an noncombustible liquid,cold engines must
have a richer mixture if they are to run properly,Every
injection system has a temperature sensor to measure
engine coolant temperature,Many injection systems have an
additional sensor to measure the temperature of the
incoming air.
Airflow Sensor
Some late model fuel injection systems monitor the
amount of air entering the engine by using an airflow sensor,
The computer takes this input and compares it with engine
RPM and manifold vacuum to determine the amount of fuel
to inject,There are three types of airflow sensors,the heated
wire,the air valve and the Karmann vortex.
2,Continuous Injection Systems (CIS)
The continuous systems are sometimes referred to as
mechanical or hydro-mechanical,because fuel metering is
determined by the mechanical relationship between an air-
flow sensor and a fuel distributor.
The first continuous systems were distinctly different
from EFI systems,since there was no electronic control of
basic fuel delivery,The continuous injection family has now
grown and spawned more highly developed versions,and
electronic control has been a part of almost all CIS fuel
injection since 1980.
小结
Pulse Fuel Injection
Pulse Fuel Injection System Components
Air induction system
Fuel delivery system
Engine control computer
Electronic Sensors
Continuous Injection Systems (CIS)
作业
熟记相关专业词汇
P60 EXERCIES Ⅰ & Ⅱ
