四大名旦汽车实用英语

2021年1月16日发(作者：窦璞)
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Unit Eight
text Engine Ignition System
All gasoline engines require some form of ignition system．The purpose of this system is
to。supply to the spark plugs，within the engine combustion chambers，high．voltage surges．
Furthermore，the ignition system must provide these surges or sparks to the correct cylinder 0f
the engine at the proper time in its operating cycle for most efficient combustion．The result of
these sparks，of course，is ignition of the air—fuel mixture within each 0f the combustion
chambers.
Modern ignition systems operate from a battery．Conventional systems consist of the battery,
ignition coil，distributor, condenser, ignition switch，spark plugs，resistor and necessary low and
high tension wiring．
The battery is the heat of the total electrical system．In regard to the primary circuit ,its
function is to supply voltage and current flow to the primary windings of the ignition coil．in order
to produce an electromagnet．
The primary side of the ignition coil connects in series between the resistor and the breaker
points· The function of this coil when current passes through it is to create a very strong


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electromagnetic field. In other words, the coil becomes an electromagnet with N and S poles .The
magnetic field from this coil, in turn, induces a voltage in the secondary windings that is necessary
to cause an arc at the spark plug gap.
The secondary ignition circuit not only transforms the 6 or 12 volts of the battery to a
voltage
high enough to cause an arc at the spark plug but also delivers this high- voltage surge to the spark
plugs. The automotive battery supplies either 6 or 12 volts to the primary coil windings. But the
voltage necessary to jump across the spark plug air gap and ignite the air-fuel mixture can range
from 5 000 to 25 000 volts or more, depending upon the engine's operating condition at any given
time.
The ignition distributor has several functions. It opens and closes the primary ignition
circuit.
It distributes the high tension current to the respective cylinders of the engine. It also has a
mechanism that controls the point at which the breaker points open, thereby advancing or
retarding
the spark in accordance with engine requirements.
The distributor cap and rotor receive the high- voltage surge from the secondary coil
windings
through a high-tension wire. This surge enters the distributor cap through its center terminal,
known
as the coil tower to spark plug electrodes formed into the rim of the cap.
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The rotor itself mounts on the upper distributor shaft and rotates with it. As a result, the
rotor
electrode moves from one cap spark plug electrode to another, following the specific firing order
of
the engine.
The purpose of the ignition condenser is to reduce arcing at the breaker points, and prolong
their life. Most automotive condensers are formed from two thin foil strips, separated by several
layers of insulation. The insulating material is known as a dielectric and is usually paper or any
similar nonconductive material.
The spark plug provides the gap in the combustion chamber across which the high-tension
electrical spark jumps to ignite the combustion charge.
The purpose of the ignition switch is to connect and disconnect the ignition system from the
battery, so the engine can be started and stopped as desired.
With the ignition switch ON, and ignition distributor contacts closed; current will flow from
the battery, through the primary winding of the ignition coil, to the distributor contact (breaker)
points, to the ground connection and back to the battery.
The current flowing through the primary winding of the ignition coil produces a magnetic
field in the coil, When the distributor contact points open (break), the magnetic field collapse and
the movement of the magnetic field induces current in the secondary winding. Since there are
many
more turns of wire in the secondary winding than there are in the primary winding, the voltage is
increased up to 20 000V.
The distributor then directs this high voltage to the proper spark plug, where it jumps to the
gap. The heat of the spark ignites the air-fuel mixture in the combustion chamber. The burning fuel
expands and forces the piston down. Downward motion of the piston, in turn, rotates the
crankshaft.
The ignition coil is a pulse transfomer designed to step up primary voltage (received from



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electromagnetic field. In other words, the coil becomes an electromagnet with N and S poles .The
magnetic field from this coil, in turn, induces a voltage in the secondary windings that is necessary
to cause an arc at the spark plug gap.
The secondary ignition circuit not only transforms the 6 or 12 volts of the battery to a
voltage
high enough to cause an arc at the spark plug but also delivers this high- voltage surge to the spark
plugs. The automotive battery supplies either 6 or 12 volts to the primary coil windings. But the
voltage necessary to jump across the spark plug air gap and ignite the air-fuel mixture can range
from 5 000 to 25 000 volts or more, depending upon the engine's operating condition at any given
time.
The ignition distributor has several functions. It opens and closes the primary ignition
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circuit.
It distributes the high tension current to the respective cylinders of the engine. It also has a
mechanism that controls the point at which the breaker points open, thereby advancing or
retarding
the spark in accordance with engine requirements.
The distributor cap and rotor receive the high-voltage surge from the secondary coil
windings
through a high- tension wire. This surge enters the distributor cap through its center terminal,
known
as the coil tower to spark plug electrodes formed into the rim of the cap.
The rotor itself mounts on the upper distributor shaft and rotates with it. As a result, the
rotor
electrode moves from one cap spark plug electrode to another, following the specific firing order
of
the engine.
The purpose of the ignition condenser is to reduce arcing at the breaker points, and prolong
their life. Most automotive condensers are formed from two thin foil strips, separated by several
layers of insulation. The insulating material is known as a dielectric and is usually paper or any
similar nonconductive material.
The spark plug provides the gap in the combustion chamber across which the high-tension
electrical spark jumps to ignite the combustion charge.
The purpose of the ignition switch is to connect and disconnect the ignition system from the
battery, so the engine can be started and stopped as desired.
With the ignition switch ON, and ignition distributor contacts closed; current will flow from
the battery, through the primary winding of the ignition coil, to the distributor contact (breaker)
points, to the ground connection and back to the battery.
The current flowing through the primary winding of the ignition coil produces a magnetic
field in the coil, When the distributor contact points open (break), the magnetic field collapse and
the movement of the magnetic field induces current in the secondary winding. Since there are
many
more turns of wire in the secondary winding than there are in the primary winding, the voltage is
increased up to 20 000V.
The distributor then directs this high voltage to the proper spark plug, where it jumps to the
gap. The heat of the spark ignites the air-fuel mixture in the combustion chamber. The burning fuel
expands and forces the piston down. Downward motion of the piston, in turn, rotates the
crankshaft.
The ignition coil is a pulse transfomer designed to step up primary voltage (received from



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Check Your Understanding
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I. Give brief answer to the following questions.
1. What is the function of the condenser in the distributor?
2. What is the function of the series resistor?
3. How does the high voltage induce in the secondary windings ?
4. What does the ignition system consist of?
II. Choose the correct word to match the sentence.
ignition induce distributor condenser
collapse electrode corona insulation
1.________the material used for insulating
2._________to produce voltage by electromagnetic induction


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3．_____________process which initiates the combustion of the compressed air-fuel
mixture in the combustion chamber
4．_________a faint glow enveloping the high-field electrode in a corona discharge，often
accompanied by streamers directed toward the low—field electrode
5．_______assembly which distributes the ignition voltage generated in the ignition coil
to the spark plugs in the firing order of the engine
6．________to fall down or inward suddenly；cave in
7．__________capacitor for the contact breaker of a conventional distributor
8．________conductor which leads curl~nt into a gas，nquid or vacuum,such as those in
a spark plug between which the spark passes to ignite the mixture
Ⅲ．Fill in the table below．
English
High-tension wiring

secondary windings

spark plug

pulse transformer

firing order

Chinese

初级绕组

串联

磁场

断电器触点

接地
IV．Translate the following sentences into Eugnsh or Chinese．
1．The distributor cap and rotor receive the high—voltage surge from the secondary coil
windings through a high—tension wire．
2．All gasoline engines require some form of ignition system．
3．点火线圈由初级线圈、次级线圈和铁心组成。
4．点火开关的作用是控制蓄电池与点火系统之间电路的通断。
Build Up Your Vocabulary
I．Write down the words that the important abbreviation stands for．
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1．Hal______________热空气进气
2．HCV____________温度调节阀
3．HEPAF______________高效微粒空气过滤器


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4．HFRT_______________高频共振技术
5．HFPR_______________燃油泵高速继电器
6．HIC________________高温怠速空气补偿阀
7．HLBL______________前照灯光束高度校止
8．HEI________________高能点火
Reading Material Electronic Ignition System
The function of the ignition system is to ignite the compressed air and fuel mixture，at
the
correct time，and initiate its combustion．In the spark ignition engine this is achieved by
means of
brief electrical arc discharge between the electrodes of the sparking plug．
In the early 1 970s many American vehicles began to install electronic ignition systems，
which
now operate as part of an electronic engine- control system．This action was necessary not
only to
meet stricter emission control standards but to increase the fuel economy of the vehicle．All
the
function that used to be done mechanically Can now be done through
electronics．Centrifugal and
Vacuum—advance mechanisms in the distributor have been eliminated．and ignition timing
is
controlled by the engine computer．
Although the electronic system costs more to install than the standard system，the
advantages
that it offers more than the drawbacks of increased cost．These advantages include：
1．greater available secondary voltage，especially at high engine rpm．
2．reliable and consistent system performance at any and all engine speeds．
3．a potential for more responsive and variable ignition advance curves．
4．decreased maintenance cost of the system．


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To understand how an electronic system can provide all these advantages over the
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standard
system, let's review for a moment the inherent negative characteristics of the standard
system. If you
recall, in order for a coil in the secondary voltage at all times, the contact points must
remain closed
for a given period of time-the dwell period. As vehicle speed increases, the points open and
close
much faster, and this reduces the effective time the points remain closed. Consequently,
there is a
reduction in the buildup time of the magnetic field around the primary coil, which is
responsible for
producing secondary voltage. This characteristic of the standard system permits it to
produce a
substantially large secondary voltage at lower engine speeds but a reduced voltage at high
rpm.
In addition, due to the fact that the contact points mechanically close and open (due
to the
action of a spring and the distributor cam), there is some arcing as the points open. This
occurs
despite a condenser in the circuit. This arcing results in point wear anti the requirement for
periodic
point replacement.
In summation, standard ignition systems fail at high engine rpm to produce sufficient
voltage
in order to prevent misfires. These misfires cause negative exhaust emissions and decreased
economy. In addition, the standard system requires frequent service on its spark plugs, due
to less
available secondary voltage at high rpm, especially as the plug's air gap grows larger due to
high
mileage. This, of course, increases emissions and reduces fuel economy.
Contact points require frequent service due to arcing. This arcing is a direct result of
high
primary coil-induced voltage, which the condenser cannot handle at low engine speeds. As a
result,
the point air gap increases so that the dwell is cut back. This reduction in dwell affects the
secondary coil's ability to produce high voltage until it reaches a point where the entire
system
malfunctions, unless the contact points receive service.
The electronic system, on the other hand, does not depend on mechanically operated
contact
points to open or close the primary coil circuit. As a result, the system can provide overall
higher
voltages necessary to fire the leaner air-fuel mixtures on emission controlled engines and also
bridge enlarged air gaps due to plug wear. Consequently, the electronic system reduces
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