组合车辆测试 – 卡友助手

组合车辆测试

题库共有99题，每次随机刷新20题，正确率80%以上即为通过。

完全正确！解释：大型组合车在**空载**时比满载更难刹住；悬架更硬、制动更猛，抓地差、更容易抱死并导致折叠。 / Exactly! EXPLANATION: Large combination vehicles take longer to stop when they are empty than when they are fully loaded. When empty, the very stiff suspension springs and strong brakes give poor traction and make it very easy to lock up the wheels causing the tractor to jackknife.

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挂车最可能发生折叠（jackknife）的情况是： / A trailer is most likely to jackknife when it is

超载时 / overloaded.

空载时 / empty.

满载时 / loaded to full capacity.

正确！解释：支腿刚接触地面后，先用**低速档**多摇几圈，略微卸掉牵引车上的重量，更容易解锁五轮并再次挂接。 / Correct! EXPLANATION: After the landing gear makes firm contact with the ground, turn crank in low gear a few extra turns. This will lift some weight off the tractor making it easier to unlatch fifth wheel, and to recouple to the trailer.

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挂接完毕后，开始摇起挂车支腿应当使用 / After you have coupled the trailer, you should start to raise the landing gear by using

高速档。 / high gear.

低速档。 / low gear.

中速档。 / intermediate gear.

正确！解释：挂车应略低于五轮，使牵引车倒入时能将其**轻微托起**。挂车太低可能顶伤鼻部，太高可能无法正确挂接。 / Bingo! EXPLANATION: The trailer should be low enough that it is raised slightly by the tractor when the tractor is backed under it. If the trailer is too low, the tractor may strike and damage the trailer nose; if the trailer is too high, it may not couple correctly.

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当你把牵引车倒到挂车下方时，应当预期： / When backing your tractor under a trailer, you should expect:

牵引车倒入车底时，挂车会被轻微托起 / Trailer will be lifted slightly when the tractor backs under it

牵引销端面与五轮顶面齐平 / End of the kingpin is even with the top of the fifth wheel

挂车支腿完全放下 / Trailer landing gear to be fully extended

正确！解释：带挂车的卡车具有危险的**后向放大**效应（鞭甩效应）。快速变道时，尾挂的摆动会被放大，导致挂车翻车。 / Right! EXPLANATION: Trucks with trailers have a dangerous crack-the-whip effect caused by rearward amplification. When you make a quick lane change, the crack-the-whip effect can turn the trailer over. There are many accidents where only the trailer has overturned.

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以下哪一项最能说明“鞭甩效应（crack‑the‑whip）”？ / Which statement best illustrates the "crack-the-whip" effect?

快速变道或突然打方向时，牵引车左右摇摆，最后一节挂车的速度迫使牵引车先翻。 / When making a quick lane change or sudden movement of the steering wheel, the tractor tends to rock and sway. The velocity of the rearmost trailer forces the tractor to roll over before the trailer.

挂车半满且货物在前部，突然打方向时，货物会猛烈滑向后部，迫使挂车翻车。 / The trailer is half full, and the cargo is loaded in the front of the trailer. When making a sudden movement of the steering wheel, the cargo will tend to forcefully slide to the back of the trailer, forcing the trailer to roll over.

快速变道或突然打方向时，最后一节挂车会向外甩，其力量被放大，导致它翻车。 / When making a quick lane change or sudden movement of the steering wheel, the rear trailer tends to swing out. The force of the rear trailer becomes amplified, causing it to roll over.

完全正确！解释：检查期间要先**固定车辆**：变速箱挂**空挡**，拉驻车制动，熄火并带走钥匙，防止他人移动。 / Exactly! EXPLANATION: Before inspection the trailer while coupling you need to secure the vehicle. Put transmission in neutral. Put parking brakes on. Shut off engine and take key with you so someone else won't move truck while you are under it.

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解挂并检查挂车支腿时，牵引车变速箱应挂在什么挡位？ / What gear should the tractor engine be in after you uncouple the trailer and are inspecting the trailer supports?

空挡（Neutral） / Neutral

低速倒挡（Low reverse） / Low reverse

高速倒挡（High reverse） / High reverse

正确！解释：拉出空气供给旋钮，或把牵引车保护阀从“normal”拨到“emergency”，以**锁住挂车制动**。 / Correct! EXPLANATION: Pull out the air supply knob or move the tractor protection valve control from normal to emergency.

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倒入挂车底下之前，务必先确认： / Before you back under a trailer, make sure the:

牵引车保护阀在“正常”位置 / Tractor protection valve is normal

挂车制动已锁定 / Trailer brakes are locked

空气制动已释放 / Air brakes are off

正确！解释：铁路道口对**低离地间隙**挂车更不友好，切勿冒险被卡住。 / Correct! EXPLANATION: Railroad tracks can also cause problems, particularly when pulling trailers with a low underneath clearance. Don't take a chance on getting hung up halfway across.

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底盘离地间隙较低的车辆在铁路道口更危险，因为 / Low underneath clearance vehicles can be risky at railroad crossings because

更容易在不平路面发生折刀。 / they are more likely to jackknife on the uneven ground.

更容易被抬高的道口卡住。 / they are more likely to get stuck on raised railroad crossings.

可能需要更长的制动距离。 / they may take longer to stop.

正确！解释：一个常用规则：**40 mph 以下**时，每 **10 英尺**车长应留 **1 秒**间隔；更高速度需**再加 1 秒**。 / Right! EXPLANATION: One good rule says you need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add 1 second for safety.

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良好路况下，你与前车至少应保持的时间间隔为：每 ______ 英尺车长留出一秒。 / Under good driving conditions, you should leave at least one second of space between your vehicle and the vehicle ahead for every ___ feet of your vehicle's length.

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正确！解释：要同时检查两处间隙：牵引车车架尾部与支腿之间；牵引车后轮胎顶端与挂车鼻部之间。 / Right! EXPLANATION: Check for enough clearance between rear of tractor frame and landing gear and between the top of the tractor tires and the nose of the trailer.

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挂车前支腿已收起、挂车已落在牵引车上，这时需要确认： / The front trailer supports are up, and the trailer is resting on the tractor, make sure:

牵引车后轮胎顶端与挂车鼻部之间留有足够间隙 / There is enough clearance between the tops of the tractor tires and the nose of the trailer

牵引车车架尾部与支腿之间留有足够间隙 / There is enough clearance between the tractor frame and the landing gear

两项都正确 / Both answers are correct

答对了！解释：若有多节挂车，最末一节挂车的后轮偏轨**最大**。 / Bingo! EXPLANATION: If there is more than one trailer, the rear wheels of the last trailer will off-track the most

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双挂或三挂车辆中，哪组车轮的“偏轨（off-tracking）”最大？ / On a double or triple vehicle, which wheels off-track the most?

牵引车的后轮 / The rear wheels of the tractor

第一节挂车的后轮 / The rear wheels of the first trailer

最后一节挂车的后轮 / The rear wheels of the last trailer

答对了！解释：确保空气压力达到**正常值**。 / Bingo! EXPLANATION: Make sure air pressure is up to normal.

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在整套空气系统达到下列哪种状态之前，你不应把牵引车倒入挂车底下： / You should not back a tractor under a trailer until the whole air system is:

在 60–80 PSI 之间。 / Between 60 and 80 PSI

达到最大气压的一半。 / Half the maximum pressure

达到正常气压。 / At normal pressure

答对了！解释：货物越多，**重心**越高，车辆越容易侧翻。满载车在事故中侧翻的概率大约是空车的**10 倍**。 / Bingo! EXPLANATION: When more cargo is piled up in a truck, the "center of gravity" moves higher up from the road. The truck becomes easier to turn over. Fully loaded rigs are ten times more likely to roll over in a crash than empty rigs.

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卡车在满载时更容易侧翻，并且 / Trucks roll over more easily when fully loaded and are

发生事故时侧翻的几率是空车的五倍。 / five times more likely to roll over in a crash than empty rigs.

发生事故时侧翻的几率是空车的十倍。 / ten times more likely to roll over in a crash than empty rigs.

发生事故时侧翻的几率是空车的两倍。 / two times more likely to roll over in a crash than empty rigs.

正确！解释：应急气路发生重大泄漏会使牵引车保护阀关闭，并触发挂车紧急制动。但只有当挂车气罐仍有压力时，制动才能保持。 / Right! EXPLANATION: A major leak in the emergency line will cause the tractor protection valve to close and the trailer emergency brakes to come on. But the brakes will hold only if there is air pressure in the trailer air tank.

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行驶中若应急气路破裂或被扯断，压力损失会导致： / Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the:

空气压缩机会卸载而不再充气 / Air compressor to unload instead of pumping air

挂车供气阀会打开 / Trailer supply valve will open

在气压降到 10 PSI 之前不会发生任何事 / Nothing will happen until air pressure reaches 10 PSI

挂车紧急制动会介入 / Emergency trailer brakes to come on

对！解释：牵引**超过 10,000 磅**挂车需要 **A 级 CDL**；拖三挂还必须在 CDL 上有**双/三挂背书**。 / Right! EXPLANATION: To legally pull a trailer with a GVWR exceeding 10,000 pounds, you'll need a Class A CDL. To pull triples, the doubles/triples endorsement on your CDL is also required.

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驾驶三挂组合车辆需要 / To drive a triple combination vehicle, you must have

带“双/三挂”背书的 A 级 CDL。 / a Class A CDL with a doubles/triples endorsement.

A级商用驾照（CDL）。 / a Class A CDL.

在你的 CDL 上有“双/三挂”背书即可。 / a doubles/triples endorsement on your CDL.

对！解释：若 1 分钟压降超过规范，说明漏气过大；不修复就上路，**可能失去制动**。 / Right! EXPLANATION: If the air pressure falls more than the specified psi in one minute for combination vehicles, the air loss rate is too much. Check for air leaks and fix before driving the vehicle. Otherwise, you could lose your brakes while driving.

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如果不做最后的空气制动漏气检查并修复， / If you do not do the final air brake check for air leaks and fix them before driving,

轮胎气压会下降。 / tire pressure will drop.

油耗会升高。 / your fuel usage will increase.

行驶中可能失去制动。 / you could lose your brakes while driving.

正确！解释：若五轮承盘缺少润滑，牵引车与挂车之间摩擦增大，可能导致**转向困难**。 / Correct! EXPLANATION: Be sure that the fifth wheel plate is greased as required. Failure to keep the fifth wheel plate lubricated could cause steering problems because of friction between the tractor and trailer.

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为什么要按规定给五轮承盘（fifth wheel plate）上润滑脂？ / Why should you be sure that the fifth wheel plate is greased as required?

防止转向出现问题 / To prevent steering problems

减少热量与噪音 / To reduce heat and noise

保证良好的电气连接 / To ensure good electrical connections

对！解释：后轮抱死抓地差，会横向滑移去“追上”前轮；拖挂时，挂车会**把牵引车侧推**，造成突然折刀。 / Right! EXPLANATION: Rear wheel braking skids occur when the rear drive wheels lock. Because locked wheels have less traction than rolling wheels, the rear wheels usually slide sideways to "catch up" with the front wheels. With vehicles towing trailers, a drive-wheel skid can let the trailer push the towing vehicle sideways, causing a sudden jackknife.

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什么是“牵引车折刀”（tractor jackknife）？ / What is a tractor jackknife?

当牵引车驱动轮被锁死，挂车继续向前推、牵引车横向甩出。 / When you lock up the drive tires on the tractor and the tractor spins out sideways as the trailer continues to push forward

当挂车驱动轮被锁死，挂车横向甩出而牵引车继续向前推。 / When you lock up the drive tires on the trailer and the trailer spins out sideways as the tractor continues to push forward

以上都不是 / Neither of the above

正确！解释：挂车手控阀（又称 trolley valve 或 Johnson bar）只用于**测试**挂车制动。 / Right! EXPLANATION: The trailer hand valve, also called the trolley valve or Johnson bar, works the trailer brakes. The trailer hand valve should be used only to test the trailer brakes.

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手控阀（挂车手柄阀）应在什么时候使用： / The hand valve should be used:

用于测试挂车制动 / To test the trailer brakes

只和脚踏制动一起配合时使用 / Only with the foot brake

只在挂车满载时使用 / Only when the trailer is fully loaded

答对了！解释：牵引车保护阀通常会在 **20–45 psi** 范围内自动关闭。 / Bingo! EXPLANATION: – 45 psi.

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牵引车保护阀通常会在厂家规定的范围、也就是大约 / The tractor protection valve is designed to close automatically when the air pressure falls into the pressure range specified by the manufacturer, typically

50 到 75 psi。 / 50 to 75 psi.

75 到 100 psi。 / 75 to 100 psi.

20 到 45 psi。 / 20 to 45 psi.

完全正确！解释：牵引车保护阀用于在挂车脱离或出现严重漏气时，**把牵引车的空气留在牵引车系统**里。它受驾驶室内的挂车供气控制阀控制；当气压过低（通常 **20–45 psi**）时会自动关闭，并释放挂车应急管路的空气，使挂车紧急制动介入。 / Exactly! EXPLANATION: The tractor protection valve keeps air in the tractor or truck brake system should the trailer break away or develop a bad leak. The tractor protection valve is controlled by the trailer air supply control valve in the cab. The control valve allows you to open and shut the tractor protection valve. The tractor protection valve will close automatically if air pressure is low (in the range of 20 to 45 psi). When the tractor protection valve closes, it stops any air from going out of the tractor. It also lets the air out of the trailer emergency line. This causes the trailer emergency brakes to come on, with possible loss of control.

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你驾驶组合车辆行驶时，挂车脱离，拉断了两根气管。你可以预期挂车制动会介入，并且： / You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and:

牵引车保护阀会关闭 / The tractor protection valve to close

牵引车会丢失全部气压 / The tractor to lose all air pressure

挂车供气阀会保持开启 / The trailer supply valve to stay open

系统驻车制动会关闭 / System parking brake will close

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