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难以割舍完整版内燃机专业英语翻译

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2021-01-19 15:26
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手机wifi设置-圣诞节前夜

2021年1月19日发(作者:姬钊)
Chapter 1 Enging types and their operation
1.1 Introduction and historical perspective
1
.内燃机的目的是从蕴含在燃料中的化学能中得到机械动力。

The purpose
of
internal
combustion
engines
is the production
of
mechanical power
from
the
chemical energy contained in the fuel .
2
.有别于外部燃烧机器 ,在内燃机中,能量是在机器内部燃烧或氧化燃料释放出来的。

In
internal
combustion
engines
,as
distinct
from
external
combustion
engines,
this
energy
is
released by burning or oxidizing the fuel inside the engine.
3
.实际上正是由于燃烧发生在机器做功部件内部才 使它们的设计和运行特征从根本上
有别于其他类型的机器。

It is the fact that combustion takes places inside the work- producing part of these engines that
makes
their
design
and
operating
characteristics
fundamentally
different
from
those
of
other
types of engine.
4.
他的专利利用将液体燃料喷入仅由压缩而加 热的空气中触发燃烧使效率高出其他类型
内燃机的两倍。更高的压缩比,不存在爆震或敲缸的现象成为可 能。

His
concept
of
initiating
combustion
by
injecting
a
liquid
fuel
into
air
heated
solely
by
compression permitted a doubling of efficiency over other internal combustion
greater expansion ratios, without detonation or knock were now possible.

发现 蒸发的油在
450

480
度的温度下经过活性催化剂可转化为高质量汽油,
比热裂解的产出高得多。这些进步以及其它改进使具有更好抗敲缸性能的燃料可以大量
生产。< br>
Houdry
found
that
vaporized
oils
passed
over
an
activated
catalyst
at
450
to
480
C
were
convented
to
high-quality
gasoline
in
much
higher
yields
than
was
possible
with
thermal
advances, and others, permitted fuels with better and better antiknock properties
to be produced in large quantities.

.
6. 留原油价格猛涨到
1970
年的几倍,
(人们)开始担心石油的长期可持续性。大 幅度提
高内燃机效率的压力明显增加。然而,排放控制的要求使改善燃料消耗举步艰难。

During the 1970s the price of crude petroleum rose rapidly to several times its cost in 1970, and
concern built up regarding the longer-term availability of petroleum. Pressures for substantial
improvements in internal combustion engine efficiency have become very substantial indeed.
Yet
emission-control
requirements
have
made
improving
engine
fuel
consumption
more
difficult.
7.
人们可能认为经过了一个多世纪,内燃机(技术)已经 达到顶峰,没有进一步改善的
潜力。实际并非如此。传统内燃机在效率、功率、排放水平方面都在不断改 善。

It might be thought that after over a century of development, the internal combustion engine has
reached
its
peak
and
little
potential
for
further
improvement
remains.
Such
is
not
the
case.
Conventional spark- ignition and diesel engines continue to show substantial improvements in
efficiency, power, and degree of emission control.
1.2 Engine classifications
8.
所有这些特征都很重要,它们显示了现有内燃机设计 的范围。由于我们想从根本上了
解内燃机的运行和排放特征,点火方式被选为最主要的分类特点。不同点 火方式(火花
点火或压缩点火)伴随使用燃料、混合物准备方法、燃烧室设计、负载控制、燃烧过程的详细过程、排放、运行特点等重要特征。

All these distinctions are important and they illustrate the breadth of engine designs available.
Because
this
book
approaches
the
operating
and
emissions
characteristics
of
internal
combustion engines from a fundamental point of view, the method of ignition has been selected
as
the
primary
classifying
feature.
From
the
method
of
ignition-spark-ignition
or
compression-ignition --follow the important characteristics of the fuel used, method of mixture
preparation,
combustion
chamber
design,method
of
load
control,
details
of
the
combustion
process, engine emissions, and operating characteristics.
1.3 Engine operation cycles
.

9.

多数往复式内 燃机以四冲程循环的形式运行。
每缸需要四个活塞冲程
(两个曲轴循环)
完成一系列事 件,输出一个做功冲程。

The majority of reciprocating engines operate on what is known as the four- stroke cycle. Each
cylinder requires four strokes of its piston---two revolutions of the crankshaft---to complete the
sequence of events which produces one power strokes
10.

进气冲程开始于活塞上止点,结束于活塞下至点,该冲程将新鲜混合气吸入缸内。
为 了提高进气量,进气阀门在冲程开始之前打开,冲程结束之后关闭。

An
intake
stroke,
which
starts
with
the
piston
at
TC
and
ends
with
the
piston
at
BC,
which
draws
fresh
mixture
into
the

increase
the
mass
inducted,
the
inlet
valve
opens
shortly before the stroke starts and close after it ends.
11.
做功冲程开始于活塞上止点,结束于下 至点,高温高压气体推动活塞向下,迫使曲柄
旋转。做功冲程作用在活塞上的功是压缩冲程活塞做功的五 倍。当活塞接近下至点,排
气门打开触发了排气过程,并将缸内压力降至接近排气压力。

A power stroke, or expansion stroke, which starts with the piston at TC and ends at BC as the
high-temperature,
high-pressure,
gases
push
the
piston
down
and
force
the
crank
to
rotate.
About five times as much work is done on the piston during the power stroke as the piston had
to do during compression. A the piston

approaches BC the exhaust valve opens to initiate the
exhaust process and drop the cylinder pressure to close to the exhaust pressure.
12.
直到活塞接近
BC

膨胀冲程的做功仍 和四冲程循环类似,
接着排气口和进气口相继打
开。大部分已燃气体在扫气过程排出气缸。当进 气口打开后,在曲轴箱内被压缩的新鲜
工质流入气缸。活塞和气口通常做成特殊形状将进入的工质偏转, 避免直接流进排气口,
以便有效扫除残余气体。

A power or expansion stroke, similar to that in the four- stroke cycle until the piston approached
BC,
when
first
the
exhaust
ports
and
then
the
intake
ports
are
uncovered.
Most
of
the
burnt
gases exit the cylinder in an charge which has been compressed in the crankcase flows into the
cylinder.
The
piston
and
the
ports
are
generally
shaped
to
deflect
the
incoming
charge
from
flowing directly into the exhaust ports and to achieve effective scavenging of the residual gases.
The engine cylinders are contained in the engine block. The block has traditionally been made
of
gray
cast
iron
because
of
its
good
wear
resistance
and
low
cost.
Passages
for
the
cooling
water
are
cast
into
the
block.
Heavy-duty
and
truck
engines
often
use
removable
cylinder
sIeeves pressed into the block that can be replaced when worn.
发动机气缸是在发动机机体内的。传统上,用有良好耐磨性 并廉价的灰铸铁做机体。冷
却水路管道铸造在机体内。重型和卡车的用可分开的气缸套压入机体,这样可 以在损坏
时替换。

13

The cylinder head

seals off the cylinders and is made of cast iron or aluminum. It must be
strong and rigid to distribute the gas forces acting on the head as uniformly as possible through
the engine block. The cylinder head contains the spark plug or fuel injector , and, in overhead
valve engines, parts of the valve mechanism.
用铸铁或铝制作 的汽缸盖封住了气缸。气缸盖必须在强度和刚度上足够好使得气体压力
尽可能均匀的分配在机体上。汽缸 盖内有火花塞或喷油器,并且在顶置式气门发动机中,
部分气门机构也在内。

14

In SI engines the air and fuel are usually mixed together in the intake system prior to entry
to the engine cylinder, using a carburetor or fuel-injection system . In automobile applications,
the temperature of the air entering the intake system is controlled by mixing ambient air with
air heated by contact with the exhaust manifold. The ratio of mass flow of air to mass flow of
fuel must be held approximately constant at about 15 to ensure reliable combustion.
汽油机用化油器或燃油喷射系统在气缸前的进气系统中将 燃油和空气混合。在汽车应用
中,在进入进气系统的空气温度是通过周围空气与和排气岐管接触被加热的 空气混合控
制的。空气的质量流量与燃料的质量流量之比必须保持恒定在约
15
左右, 以确保可靠的
燃烧。

15

Fuel injection into the intake manifold or inlet port is an increasingly common alternative to
a
carburetor.
With
port
injection,
fuel
is
injected
through
individual
injectors
from
a
low-pressure
fuel
supply
system
into
each
intake
port.
There
are
several
different
types
of
systems:
mechanical
injection
using
an
injection
pump
driven
by
the
engine;
mechanical,
driveless, continuous injection; electronically controlled, driveless, injection. Figure 1-7 shows
an example of an electronically controlled system. In this system, the air flow rate is measured
directly;
the
injection
valves
are
actuated
twice
per
cam
shaft
revolution
by
injection
pulses
whose duration is determined by the electronic control unit to provide the desired amount of
fuel per cylinder per cycle.
燃料喷射到进气歧管或进气口 成为越来越普遍替代化油器的方案。通过进气口喷射,燃
料从低压燃油供应系统通过每个喷射器喷射到各 进气口。有以下几种不同类型的系统:
使用由发动机驱动的喷油泵机械喷射
;
机械式的 ,无驱动,可连续喷射
;
电子控制的,无驱
动,喷射。如图
1-7
所 示,展示了电控喷射系统。在该系统中,空气流量可直接测量
;

油脉冲控制着凸轮轴 转一圈喷油阀驱动两次,用电控单元控制喷油脉冲的时长来控制着
每缸所需的循环供油量。

16

The sequence of events which take place inside the engine cylinder is illustrated in Fig. 1-8.
Several
variables
are
plotted
against
crank
angle
through
the
entire
four-stroke
cycle.
Crank
angle is a useful independent variable because engine processes occupy almost constant crank
angle intervals over a wide range of engine speeds.
在发动机汽缸内发生的 事件顺序示于图
1-8
。几个变量在整个四冲程循环用曲轴转角表示
来作图。曲轴转角 是一个有用的独立变量,因为在宽范围内的发动机转速下,发动机冲
程占用曲柄角间隔几乎不变。

17

There is an optimum spark timing which, for a given mass of fuel and air inside the cylinder,
gives maximum torque. More advanced

timing or retarded

timing than this optimum gives
lower
output.
Called
maximum
brake-torque
timing,?
this
optimum
timing
is
an
empirical
compromise between starting combustion too early in the compression stroke and completing
combustion too late in the stroke .
已知缸内的燃油量和进气量,为输出最大扭矩,存在一个最佳的点火时刻。 提前或延后
点火时刻时输出的转矩都低于最佳时的。所谓的最大制动力矩的时间,其最佳时机是在
压缩冲程中过早开始燃烧和完成燃烧冲程太晚之间的经验妥协

18

Multicylinder engines are invariably used in automotive practice. As rated power increases,
the advantages of smaller cylinders in regard to size, weight, and improved engine balance and
smoothness
point
toward
increasing
the
number
of
cylinders
per
engine.
An
upper
limit
on
cylinder
size
is
dictated
by
dynamic
considerations:
the
inertial
forces
that
are
created
by
accelerating and decelerating the reciprocating masses of the piston and connecting rod would
quickly
limit
the
maximum
speed
of
the
engine.
Thus,
the
displaced
volume
is
spread
out
amongst
several
smaller
cylinders.
The
increased
frequency
of
power
strokes
with
a
multicylinder engine produces much smoother torque characteristics.
多缸发动机都不约 而同地应用于车载发动机。随着额定功率的增加,小气缸在尺寸,重
量,和改进的发动机平衡和平稳的优 势使得发动机的气缸数目在不断增加。气缸大小的
上限是由动力学考虑决定:在加速或减速的往复运动中 活塞和连杆的质量产生的惯性力
会很快限制发动机的最高转速。因此,排量就分摊在几个较小的气缸。增 加了做工冲程
的频率增使得多缸机有更平滑的扭矩输出特性。

19

Note, however, that the motion of the piston is more rapid during the upper half of its stroke
than
during
the
lower
half .
The
resulting
inequality
in
piston
acceleration
and
deceleration
produces
corresponding
differences
in
inertia
forces
generated.
Certain
combinations
of
cylinder number and arrangement will balance out these secondary inertia force effects.
然而, 请注意,在活塞的运动中其上半冲程比在下半冲程快。在活塞的加速和减速中相
应产生的惯性力造成了不 平衡。气缸数量和布置一定的组合确实将平衡这些二次惯性力
的影响。

20

Turbochargers are used to increase the maximum power that can be obtained from a given
displacement engine. The work transfer to the piston per cycle, in each cylinder, which controls

手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜


手机wifi设置-圣诞节前夜



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