车辆工程专业英语

UNIT 5

FUEL INJECTION SYSTEM

燃油喷射系统

Fuel injection systems have been used on vehicles for many years. The earliest ones were purely mechanical.

As technology advanced, electronic fuel injection systems became more popular. Early mechanical and electronic

fuel injection systems did not use

feedback controls

.

As emissions became more of a concern

, feedback controls

were

adapted

to both types of fuel injection systems.

feedback control

反馈控制

As emissions became more of a concern

随着排放越来越受到关注

were adapted to

被应用于

Both mechanical and electronic fuel injection systems can be found on

gasoline engines. Diesel engines

are

most commonly found

with

mechanical type systems, although the

newest generations

of these engines have been

using electronic fuel injection(EFI) .

gasoline engines

汽油发动机

diesel engines

柴油发动机

newest generations of

最新的

5.1

Basic Theory

EFI uses

solenoid

valves called

injectors

to meter

fuel

delivery

. Most vehicles today use 1 injector per

cylinder

. When the solenoid is

energized

, fuel

sprays out into

the

valve port

. Fuel is delivered to the injector by a

high- pressure

electric pump

at around 40

psi

. Fuel delivery is controlled by the injectors which

are cycled by

the

computer. The computer produces a signal to open the injectors for

a certain length of time

depending on

engine

conditions relayed by sensors

. The longer that the injector is open, the more fuel is injected. As engine load and

rpm are increased, the injector open times are increased to

match

increasing airflow. This computer output signal

is called the injector

pulse

width

. The longer the pulse width, the more fuel is injected.

solenoid valves

电磁阀

injector

喷油嘴，喷油器，喷射器

fuel delivery

燃油输送，燃油供给

is energized

v.

使通电

,

供能

,

激发，加强

adj.

通电的，激励的

,

增能的

energized line

带电电路，带

电线路

valve port

阀口，喷油嘴

psi [psai]

每平方英寸

…

.

磅

=

pounds per square inch

are cycled by

周期性控制

engine conditions relayed by sensors

传感器传送

/

输送回来的信号体现的发动机工作状况，简单的说，

< br>即：传感器信号体现的发动机工作状况

injector pulse width

喷油器脉冲宽度

5.3

Fuel System

5.4

Air Metering and Measurement

5.5

Most EFI systems measure the same basic 6 input

RPM

Airflow

空气流量

Manifold Pressure

歧管压力

On

speed density type systems

, this input is

essential

when

combined with

the rpm signal to calculate airflow.

As the

throttle

is opened, the manifold pressure increases which will require more fuel.

speed density type system

“速度

-

密度”类型的系统，即：采用“速 度

-

密度”方法来测量空气流量的

系统

Throttle Position

节气门位置

This input is a

secondary input

on most systems. It is required mainly for

acceleration

enrichment

when the

throttle is rapidly opened. By

looking at the rate of change

of

throttle blade angle

, the computer can

determine

how quickly the throttle is being opened and can supply the

extra

fuel required

momentarily

to

alleviate

the

lean

condition

. Throttle position is measured by a

potentiometer

attached to the throttle shaft.

acceleration enrichment

加速加浓，即：汽车加速时的混合气加浓

looking at the rate of change of throttle blade angle

查看

节气门叶片转角

的变化速率

determine

确定

momentarily [' m

?

um

?

n t

?

rili]

adv.

即刻，随时地，暂时地

,< /p>

立刻

alleviate [

?

'li:vieit]

v.

减轻

,

使

...

缓和，使（痛苦等）易于忍受

alleviate burdens

减负

lean condition

稀混合气工况

←←→→

rich condition

浓混合气工况

potentiometer [p

?,tēn

?

i'

?

mit

?

]

电位计

分压计，电位器，电势计

Water Temperature

Air Temperature

5.6

Oxygen Sensor

氧传感器

This sensor is

employed

in

closed loop systems

to modify the basic pulse width

after the fact

. It is mounted

into the exhaust manifold area. By looking at the

oxygen content

of the exhaust gasses after

combustion,

the

computer can determine if the air/fuel ratio is too rich or too lean for

optimum

combustion and adjust

the next few

injections

accordingly. This sensor is primarily employed for

emission

control

and

to a lesser degree

, fuel

economy. For the lowest average emissions, the air/fuel ratio must be kept around 14.7 to 1.

is employed in

应用于，忙于，从事于

closed loop systems

闭环控制系统

modify the basic pulse width after the fact

事后调节基本脉冲宽度

oxygen content

氧含量

combustion

燃烧

the next few injections

接下来的

/

后面的一些喷油

(

< br>脉宽

)

emission control

排放控制

to a lesser degree

在更轻的程度上，其次

Under

full throttle conditions

, this sensor input is

ignored

by the computer so that the engine can produce

more power. This is called

open loop mode

and the computer is supplying the injector pulse width from

tables

based on all of the other sensor

inputs

. Once throttle opening and rpm are reduced to

cruising conditions

, most

systems will

jump back into

the closed loop mode where they will

stay for a large portion of the time

on most

street

driven

applications

.

full throttle conditions

节气门 全开的情况

/

工况

open loop mode

开环控制模式

supplying the injector pulse width from tables based on all of the other sensor inputs

根据（除了氧传感器

之外的）其它所有的传感器输入信号得到的（喷油）数据表来提供喷油器脉宽

< br>

cruising conditions

巡航工况

street driven applications

街道驾驶应用，意译

即：街道行驶情况

5.7

Basic Operation

As explained in the Basic Theory

section

, the computer processes all of the voltage signals from the various

sensors to determine the engine operating conditions

at the moment

and delivers the

appropriate

pulse width to

the injectors. If engine airflow increases by 10%, the pulse width is also increased by about 10% to keep the

air/fuel ratio

constant

. If the rpm is doubled from 2,000 to 4,000 rpm, the numbers of injections are also

doubled

to

double

the fuel flow.

The computer looks at the changes in sensor inputs

every few milliseconds

in order to be ready to

modify

the

pulse width if any

parameter

changes.

Section

章节，部分

at the moment

此刻

,

目前，现在

at the right moment

适时

appropriate [

?

'pr

?uprī:?

t]

adj.

适当的

v.

拨出（款项）

(

某目的

)

之用

constant ['k

?

nst< /p>

?

nt]

adj.

恒定的

,

经常的

,

不变的，持久的

n.

常数

,

恒量

every few milliseconds

每隔几毫秒

parameter [p

?'r?mīt?

]

n.

参数

,

参量

NEW WORDS

1. feedback

反馈

2. injector

喷油嘴，注射者

,

注射器

,

喷射给水器

3. sensor

7. alleviate

减轻

,

使< /p>

...

缓和

8. momentarily

即刻，立刻

,

随时地，暂时地

PHRASES AND EXPRESSIONS

1. electric pump

电动泵

2. pulse width

脉冲宽度

3. fuel rail

油轨

4. return line

回油路

5. fuel pressure

regulator

燃油压力调节器

6. throttle body assembly

节气门体总成

8. measure off

测量出

9.

hall

effect sensor

霍尔效应传感器

10. taper off

使渐渐减少

,

逐渐停止，使渐渐变尖

,

一头逐渐变细

UNIT 6

EXHAUST SYSTEM

排放系统

The exhaust system carries

exhaust gases

from the engine’s combustion chamber to the atmo

sphere and

reduces, or

muffles

, engine noise. Exhaust gases leave the engine in a pipe, traveling through a

catalytic converter

and a

muffler

before exiting through the

tailpipe

.

exhaust gases

废气

combustion chamber

燃烧室

muffle

抑制

,

发低 沉的声音

n.

低沉的声音

,

消音器

catalytic converter

催化转化器

muffler

消声器，围巾

,

头巾

,

厚手套

tailpipe ['teilpaip]

排气尾管，尾管，尾喷管

,

排气管

,

吸管

perforated tailpipe

带眼尾管

6.1

The Tailpipe

The tailpipe is a long

metal

tube

attached to the muffler. It

sticks out

from under the body of a car, at the rear,

in order to

discharge

the exhaust gases from the muffler of the engine into the air outside the car.

stick out

突出

,

伸出，显眼，坚持到底

stick it out

坚持到底，顶住，忍耐到底

6.2

The Muffler

6.3

The Exhaust Manifold and

Header

排气歧管和集气管

6.4

The Manifold to Exhaust Pipe

Gaskets

gasket

['g?skit]

n.

衬垫< /p>

,

垫圈，垫片，密合墊，橡胶垫

6.5

Exhaust Pipe

Hangers

吊耳

6.6

Exhaust Pipe

6.7

Dual

Exhaust System

双排气系统

The advantage of a dual exhaust system is that the engine

exhausts

more freely, thereby

lowering

the

backpressure, which is

inherent

in an exhaust system. With a dual exhaust system, a

sizable

increase

in engine

horsepower

can be

obtained

because the

“breathing” capacity

of the engine is improved, leaving less exhaust

gases in the engine at the end of each

exhaust

stroke

. This, in turn,

leaves more room

for an

extra

intake of the

air-fuel mixture.

inherent [īn'hi?

r

?

nt]

adj.

内在的

< br>,

固有的，生来的，先天的

sizable ['saiz

?

bl]

相当大的，大的，可调大小的

breathing capacity

呼吸能力，即：汽车的进气排气性能

exhaust stroke

排气冲程

NEW WORDS

1. tremendous

3. muffler

4. tailpipe

5. hanger

6. manifold

7. fiberglass

['faib

?

gl

ɑ

:s]

玻璃纤维，纤维玻璃，玻璃丝

8. speaker

扬声器

9. header

集气管

12. flat

13. socket

['s

?

kit]

n.

插座

,

插口

antenna socket

天线插座

plug socket

插座，电源插座，安全阀、突开阀

14. sizable

16. bump

撞击

,

碰撞

,

颠簸而行

n.

撞击

,

隆起物

PHARSES AND EXPRESSIONS

1. stick out

2. the body of a car

车身

3. cast iron

铸铁

4. catalytic converter

5 . out of phase with

adj.