捷達(dá)轎車電器教學(xué)實(shí)驗(yàn)臺(tái)改造設(shè)計(jì)與制作
捷達(dá)轎車電器教學(xué)實(shí)驗(yàn)臺(tái)改造設(shè)計(jì)與制作,捷達(dá)轎車電器教學(xué)實(shí)驗(yàn)臺(tái)改造設(shè)計(jì)與制作,捷達(dá),轎車,電器,教學(xué),實(shí)驗(yàn),試驗(yàn),改造,設(shè)計(jì),制作
附 錄
附錄A:英文文獻(xiàn)
AUTO ELECTRIC APPLIANCES
1、Starting System
Automobile engines are not self-starts. In order to start them, the engine crankshaft must be turned over. To do this, the starter motor receives electrical power form the storage battery. The starter motor then converts this energy into mechanical energy, which it transmits through the drive mechanism to the engine’s fly wheel.
The starter motor draws a great deal of electrical current from the battery. A large starter motor might require 300 to 400 amperes of current. This current flows through the heavy gauge cables that connect the battery to the starter.
The drive controls the flow of this current using the starting switch. However, if the cables were routed from the battery to the starting switch and then on to the starter motor, the voltage drop caused b resistance in the cables would be too great. To avoid this problem, the system is designed with two connected circuits: the starter circuit and the control circuit.
1.1 The starting safety switch
The starting safety switch is also called a neutral start switch. It is a normally open switch that prevents the starting system from opening when the automobile’s transmission is in gear. If the car has no starting safety switch, it is possible to spin the engine with the transmission in gear. This will make the car lurch forward or backward which could be dangerous. Safety switches or interlock devices are used with all automatic transmissions and on many late-model cars with manual transmissions. The safety switch can be an electrical switch that opens the control circuit if the car is in gear. It can also be a mechanical interlock device that will not let the ignition switch turn to start if the car is in the gear.
1.2 Magnetic Switch (Relays and Solenoids)
A magnetic switch in the starting system allows the control circuit to open and close the starter circuit. The switch can be a:
（１）Relay which uses the electromagnetic field of a coil to attract an armature and close the contact points.
（２） Solenoid which uses the electromagnetic field of a coil to pull a plunger into the coil and close the contact points. The plunger’s movement can also be used to do a mechanical job, such as shifting the starter motor gear in a solenoid-actuated drive.
1.3 Starter Motor
The starter motor converts electrical energy from the battery into mechanical energy to turn the engine. It does this through the interaction of magnetic fields. When current flows through a conductor, a magnetic field is formed around the conductor. If the conductor is placed in another magnetic field, the two fields will be weakened at one side and strengthened at the other side. An automotive starter motor has many conductors and uses a lot of current to create enough rotational force to crank the engine.
The armature is the collection of conductors that will spin to crank the engine. The starter drive gear is mounted on the armature shaft. The pole pieces are the stationary magnetic fields. The motor housing encloses the armature and pole pieces, holds the bearings that support the armature shaft, and provides the terminals for connecting the motor to the rest of the staring system.
2.I gniting System
The ignition system on an internal combustion engine provides the spark that ignites the combustible air/fuel mixture in the combustion chamber. The spark consists of an electric are produced by applying a high voltage across the electrodes of a spark plug. This spark must occur near the end of the compression stroke, as the position approaches top dead center (TDC). The cylinders must fire in the proper order and at a precise instant, depending on engine speed, load and temperature conditions.
A spark plug consists of a pair of electrodes called the center and ground electrodes, separated by a gap. A spark is produced by applying a high voltage (from approximately 6 KV to 40 KV) between the center electrode and ground. Once the arc is started, a much lower voltage is required to sustain the arc to ignite the air/fuel mixture.
The ignition system is divided into two circuits: the primary and the secondary. The primary circuit is the low-voltage side of the system and controls the secondary circuit, which is the high-voltage side of the system.
The following are the basic parts of the primary ignition circuit:
（１）Battery and/or alternator. Supplies the low voltage (12V) used to operate the primary circuit.
（２） Ignition switch. Key-operated switch used to feed battery voltage to the primary circuit.
（３） Primary wires. Low voltage wires used to connect the electrical components of the primary circuit.
（４） Ignition coil primary winding. Current flow through the coil produces an electromagnetic field, which is used to induce a high voltage in the secondary coil.
（５） Electronic control unit. Contains a switching transistor controlled by a speed sensor and is used to open and close the primary circuit.
（５）Speed sensor, or pickup. Produces a pulsating voltage that signals the generation of an ignition spark.
The following are the basic parts of a secondary ignition circuit:
（１）Ignition coil secondary winding. Has a high voltage (40,000 V or more) induced in it each time the primary magnetic field collapses.
（２）Coil wire. Heavily insulated wire that feeds high voltage from the ignition coil to distributor cap.
（３） Distributor rotor. Operates in conjunction with the distributor cap to distribute the high voltage from the ignition coil to the individual spark plug wires in the firing order.
（４） Distributor cap. Insulated cap that transfers high voltage from the distributor rotor to spark plug wires.
（５） Spark plug wire. Heavily insulated wire that carries high voltage from the distributor to the spark plugs.
（６）Spark plug. Provides the air gap within the combustion chamber for the high voltage to arc across, thus igniting the air/fuel mixture.
３、Lighting Circuit
The lighting system in a typical automobile includes the headlight, parking lights, direction-signal lights, side marker, stoplights, tail lights, and interior lights.
3.1 Main Lighting Switch
The main lighting switch (sometimes called the headlight switch) is the heart of the lighting systems. It controls the headlights, parking lights, side marker lights, taillights, license plate light, instrument panel lights, and interior lights.
Individual switches are provided for special purpose lights such as directional signals, hazard warning flashers, back up lights, and courtesy lights. The main lighting switch may be of either the “push-pull” or “push-pull with rotary contact” types. A typical switch will have three positions: off, parking, and headlamps. Some switches also contain a rheostat to control the brightness of the instrument panel lights. The rheostat is operated by rotating the control knob, separating it from the push-pull action of the main lighting switch.
When the main lighting switch completes the circuit to the headlamps, the low beam lights the way for city driving and for use when meeting oncoming traffic on the highway. When the dimmer switch is actuated, the single filament headlamps go “on”, along with the high beam of the two filament headlamps. The next actuation of the dimmer switch returns the headlight system to low beams only on the two filament lamps. Some cars are equipped with and electronic headlight dimming device, which automatically switches the headlights from high beam to low in response to light from an approaching vehicle or light from the taillight of a vehicle being overtaken. The dimmer switch in the automatic headlamp dimming system is a special override type. It is located in the steering column as part of a combination dimmer, horn, and turn signal switch. The override action occurs when a slight pull toward the driver on the switch lever providers high beam headlights regardless of the amount of light on the sensor-amplifier.
For some years there has been discussion about the advantages of a polarized headlight system. Such a system comprises headlights which produce polarized light in a particular plane. The windscreens of all cars would be fitted with polarizing glass, which would be oriented so that glare from an approaching vehicle would be essentially eliminated, while the forward vision would still be kept at the present levels. The advantages the system appear attractive, but the practical problems of making the transition are very great, since it would not be practical to convert all existing vehicles to this type of lighting. Also, any benefits would only be marginal because glare itself is not a frequent cause of accidents. However, many cars now have refracting or colored glass to cut down on glare.
3.2 Directional Signal Switch
The directional signal switch is installed just below the hub of the steering wheel. A manually controlled lever projecting from the switch permits the driver to signal the direction in which he wants to turn. Moving the switch handle down will light the “turn signal” lamps on the left front and left rear of the car, signaling a left turn. Moving the switch upward will light the turn signal lamps on the right (front and rear), signaling a right turn. With the switch in a position to signal a turn, lights are alternately turned “on” and “off” by a turn signal flasher. Incorporated in the directional signal switch is a “l(fā)ane change switch mechanism”. This feature provides the driver the opportunity to signal a lane change by holding the turn lever against a dent, then releasing it so cancel the signal immediately after the maneuver is completed.
3.3 Stoplight Switch
In order to signal a stop, a brake pedal operated “stoplight switch” is provided to operate the vehicle’s stop lamps. In addition to lighting the conventional rear lights, the switch also operates the center high-mounted stop lamp, which became mandatory on later models. Cruise control equipped vehicles may also utilize a vacuum release valve. In this case, both the vacuum release valve and the stoplight switch are actuated by movement of the brake pedal.
附錄B:中文文獻(xiàn)
汽車電器
1、啟動(dòng)系統(tǒng)
汽車發(fā)動(dòng)機(jī)是不能自動(dòng)啟動(dòng)的。為了啟動(dòng)發(fā)動(dòng)機(jī)，曲軸必須先運(yùn)轉(zhuǎn)起來。為此，啟動(dòng)機(jī)必須從蓄電池得到足夠的電能。接著啟動(dòng)機(jī)將這部分電能轉(zhuǎn)化成機(jī)械能，通過驅(qū)動(dòng)機(jī)構(gòu)傳到發(fā)動(dòng)機(jī)曲軸飛輪上。
啟動(dòng)機(jī)需要蓄電池提供大量的電流。一個(gè)大型的啟動(dòng)機(jī)需要大約300~400安培的電流。電流通過重型電纜從蓄電池連接到啟動(dòng)機(jī)上。
駕駛員通過啟動(dòng)開關(guān)來控制這個(gè)電流。如果導(dǎo)線從蓄電池經(jīng)過啟動(dòng)開關(guān)連接到啟動(dòng)機(jī)上，在導(dǎo)線上會(huì)產(chǎn)生大量的電壓降。為了避免這個(gè)問題，啟動(dòng)系統(tǒng)設(shè)計(jì)有兩套電路：啟動(dòng)機(jī)電路和控制電路。
1.1安全啟動(dòng)開關(guān)
啟動(dòng)安全開關(guān)又稱為空檔啟動(dòng)開關(guān)。它是一個(gè)常開開關(guān)，用來防止在汽車掛擋后啟動(dòng)系統(tǒng)工作。如果沒有安全啟動(dòng)開關(guān)，啟動(dòng)系統(tǒng)很可能在掛擋后工作。這種情況是非常危險(xiǎn)的，將會(huì)使汽車前進(jìn)或后退。安全開關(guān)或者互鎖裝置在所有的自動(dòng)排擋或手動(dòng)排擋的汽車上都有應(yīng)用。安全開關(guān)可以是一種電子開關(guān)，當(dāng)汽車掛擋后，它斷開控制電路。同樣，安全開關(guān)也可以是機(jī)械互鎖裝置，當(dāng)汽車掛擋后不允許點(diǎn)火開關(guān)轉(zhuǎn)到啟動(dòng)位置。
1.2電磁開關(guān)
啟動(dòng)系統(tǒng)的電磁開關(guān)用于控制控制電路斷開或接通啟動(dòng)機(jī)電路。開關(guān)形式如下：
（１）繼電器： 利用吸引線圈產(chǎn)生磁場，吸引銜鐵并閉合觸點(diǎn)。
（２）電磁線圈：利用吸引線圈產(chǎn)生磁場，推動(dòng)柱塞進(jìn)入線圈并閉合觸點(diǎn)。柱塞通常是機(jī)械運(yùn)動(dòng)，就如使啟動(dòng)機(jī)掛擋的電磁驅(qū)動(dòng)裝置一樣。
1.3啟動(dòng)機(jī)
啟動(dòng)機(jī)將蓄電池的電能轉(zhuǎn)化為驅(qū)動(dòng)發(fā)動(dòng)機(jī)啟動(dòng)的機(jī)械能。它是利用電磁互感的原理制成的。通有電流的導(dǎo)體在其周圍會(huì)產(chǎn)生磁場。當(dāng)這樣的導(dǎo)體被放置到另一個(gè)磁場中時(shí)，兩個(gè)磁場將有一側(cè)被加強(qiáng)而另一側(cè)被減弱。當(dāng)大電流流過汽車啟動(dòng)機(jī)的線圈時(shí)，可以產(chǎn)生足以讓發(fā)動(dòng)機(jī)曲軸轉(zhuǎn)動(dòng)的力矩。
電樞由線圈組成用以使發(fā)動(dòng)機(jī)曲軸轉(zhuǎn)動(dòng)。啟動(dòng)機(jī)驅(qū)動(dòng)安裝在電樞轉(zhuǎn)軸上的齒輪。磁極產(chǎn)生穩(wěn)定磁場。啟動(dòng)機(jī)外殼內(nèi)裝入電樞與磁極，外殼兩端的軸承支撐電樞轉(zhuǎn)軸，并將啟動(dòng)機(jī)與啟動(dòng)系統(tǒng)支架相連。
2、點(diǎn)火系統(tǒng)
內(nèi)燃機(jī)的點(diǎn)火系統(tǒng)產(chǎn)生電火花，點(diǎn)燃燃燒室的可燃混合氣體。火花由電弧產(chǎn)生，是由經(jīng)過火花塞電極的高電壓形成的。火花應(yīng)該在接近壓縮行程終了的時(shí)候產(chǎn)生，即活塞位于接近上止點(diǎn)（TDC）。各缸的點(diǎn)火應(yīng)該有合適的順序和精確的時(shí)間，這取決于發(fā)動(dòng)機(jī)的轉(zhuǎn)速、負(fù)荷和溫度。
火花塞由一對電極組成，稱為中心電極和塔鐵（旁）電極由一個(gè)間隙分開。火花由在中心電極和旁電極之間的高電壓（大約6千伏到40千伏）產(chǎn)生。一旦電弧產(chǎn)生，必須有一個(gè)較低的電壓來維持電弧點(diǎn)燃混合氣。
點(diǎn)火系統(tǒng)分為兩條回路：初級(jí)和次級(jí)。初級(jí)回路是系統(tǒng)的低壓端，并控制這次級(jí)回路，而次級(jí)回路是系統(tǒng)的高壓端。
初級(jí)回路由以下基本部分組成：
（１）蓄電池和發(fā)電機(jī)。提供低壓電（12伏）讓低壓電路正常工作。
（２）點(diǎn)火開關(guān)。通過點(diǎn)火開關(guān)的控制，把蓄電池電壓提供給初級(jí)電路。
（３）初級(jí)導(dǎo)線。低壓導(dǎo)線用來連接初級(jí)回路的各個(gè)部件。
（４）點(diǎn)火線圈初級(jí)繞組。電流通過線圈，產(chǎn)生一個(gè)電磁場，用來在次級(jí)線圈中產(chǎn)生高電壓。
（５）電子控制單元。包括由轉(zhuǎn)速傳感器控制的開關(guān)晶體管，用來斷開或接通初級(jí)電路。
（６）轉(zhuǎn)速傳感器或者感應(yīng)線圈。產(chǎn)生一組脈沖電壓，給點(diǎn)火火花的產(chǎn)生提供信號(hào)。
次級(jí)回路由以下基本部分組成：
（１）點(diǎn)火線圈次級(jí)繞組。當(dāng)初級(jí)回路的電磁場每一次消失的時(shí)候，會(huì)產(chǎn)生一個(gè)高電壓（40 000伏或更高）。
（２）（線圈）高壓導(dǎo)線（中央高壓線）。導(dǎo)線必須確保絕緣，以保證高電壓從點(diǎn)火線圈傳輸?shù)椒蛛娖魃w。
（３）分電器的分火頭。作用是與分電器蓋相連，把高電壓從點(diǎn)火線圈分配到需要點(diǎn)火的火花塞導(dǎo)線上。
（４）分電器蓋。該蓋子是絕緣的，確保高電壓從分火頭傳輸?shù)交鸹ㄈ麑?dǎo)線上。
（５）火花塞導(dǎo)線（分缸高壓線）。導(dǎo)線必須確保絕緣，以保證高電壓從分電器傳輸?shù)交鸹ㄈ?
（６） 火花塞。在燃燒室里提供空氣間隙，保證高電壓的電弧通過，來點(diǎn)燃混合氣。
3、照明線路
普通車的照明系統(tǒng)包括前照燈、泊車燈、轉(zhuǎn)向信號(hào)燈、輪廓燈、制動(dòng)燈、倒車燈、尾燈以及車內(nèi)燈。
3.1燈光總開關(guān)
燈光總開關(guān)（有時(shí)叫做前照燈開關(guān)）是照明系統(tǒng)的心臟。它控制前照燈、泊車燈、輪廓燈、尾燈、牌照燈、儀表板燈和車內(nèi)燈。
個(gè)別的開關(guān)被提供作為控制特別的燈，像是轉(zhuǎn)向信號(hào)、危險(xiǎn)警告閃爍裝置、倒車燈和禮貌燈。燈光總開關(guān)可能是“拉桿式的”或“拉桿及旋鈕式”類型。一個(gè)典型的開關(guān)一般有三個(gè)位置：關(guān)閉、泊車和前照燈。一些開關(guān)也包含一個(gè)可變電阻器，控制儀表板燈的燈光亮度?？勺冸娮杵饔尚D(zhuǎn)的控制手柄操縱，與燈光總開關(guān)的推一拉的操縱是分開的。
當(dāng)燈光總開關(guān)接通前照燈線路的時(shí)候，近光燈絲點(diǎn)亮，為在城市道路駕駛和在高速公路上輛車交會(huì)時(shí)提供照明。在變光開關(guān)工作時(shí)，單絲前照燈打開，同時(shí)雙絲前照燈的遠(yuǎn)光燈也一起打開。變光開關(guān)的另一個(gè)接通時(shí)，雙絲前照燈上只有近光燈打開。一些汽車裝備了前照燈電子變光裝置，當(dāng)接收到一輛逐漸靠近的汽車的燈光時(shí)，或接收到前面被趕上的車的尾燈燈光時(shí)，能自動(dòng)地將前照燈從遠(yuǎn)光轉(zhuǎn)變到近光。自動(dòng)前照燈的變光開關(guān)是一種特別的開關(guān)。它位于轉(zhuǎn)向柱上，作為組合變光開關(guān)、喇叭和轉(zhuǎn)向信號(hào)開關(guān)的一部分。輕輕朝著駕駛員的方向拉動(dòng)開關(guān)控制桿這一動(dòng)作，就可以使前照燈遠(yuǎn)光燈泡點(diǎn)亮，而不用顧及燈的數(shù)量。
近年來，人們開始討論有關(guān)偏振光的前照燈系統(tǒng)的優(yōu)勢。一個(gè)這樣的系統(tǒng)包括能產(chǎn)生偏振光的特殊面的前照燈。所有的汽車擋風(fēng)玻璃會(huì)配備有偏振光玻璃，這樣，來自某一正在接近的汽車的眩目的光線會(huì)被定向除去，于是向前的視角就能夠保持當(dāng)前的水平方向。該系統(tǒng)的有時(shí)顯得很有吸引力，但是實(shí)際的制造上的問題非常大，因?yàn)閷F(xiàn)存汽車全部改換成這種系統(tǒng)顯然不實(shí)際。這些益處只是次要的，因?yàn)檠Ｄ勘旧聿⒉皇且馔馐录l(fā)生的常見因素。因此，許多汽車現(xiàn)在裝備使光線折射的玻璃或把玻璃染色來減少眩目的影響。
3.2轉(zhuǎn)向開關(guān)
轉(zhuǎn)向開關(guān)就安裝在轉(zhuǎn)向柱轂的下面。從開關(guān)上突出的一個(gè)用手控制的杠桿使駕駛員能根據(jù)所轉(zhuǎn)的方向顯示轉(zhuǎn)向信號(hào)。向下移動(dòng)開關(guān)柄將會(huì)點(diǎn)亮車輛左前和左后的“轉(zhuǎn)向信號(hào)燈”，表示向左轉(zhuǎn)。向上移動(dòng)開關(guān)將會(huì)點(diǎn)亮車輛右邊（前面和后面）的燈，表示向右轉(zhuǎn)。籍由一個(gè)轉(zhuǎn)向開關(guān)表示方向信號(hào)，轉(zhuǎn)向燈被一個(gè)轉(zhuǎn)向信號(hào)閃光器交替地控制“ON”和“OFF”。合并在轉(zhuǎn)向開關(guān)中的是一個(gè)“變換開關(guān)機(jī)構(gòu)”。該特征提供給駕駛員一個(gè)機(jī)會(huì)來握住轉(zhuǎn)向桿，靠向一個(gè)爪來表示一個(gè)變換信號(hào)，在操縱完之后，釋放它就可以立刻取消該信號(hào)。
3.3制動(dòng)燈開關(guān)
為了要表示停車，由剎車踏板操縱“制動(dòng)燈開關(guān)”控制汽車的制動(dòng)燈、除了傳統(tǒng)照明的后燈，開關(guān)也控制中央高位剎車燈，在最新的車型中是強(qiáng)制性安裝的。裝備了巡航控制的汽車也可能利用一個(gè)真空釋放閥。在這種情況下，真空釋放閥和制動(dòng)燈開關(guān)都有剎車踏板的運(yùn)動(dòng)控制。
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