气刹测试

解释：空气压缩机通常在约 100 psi 开始充气、约 125 psi 停止，因此在约 125 psi 时系统可视为充满。 / EXPLANATION: Pumping by the air compressor should start at about 100 psi and stop at about 125 psi.

解释：**当弹簧制动已介入时，切勿**踩下制动踏板；弹簧力与气压的合力可能损坏制动器。 / EXPLANATION: Never push the brake pedal down when the spring brakes are on. If you do, the brakes could be damaged by the combined forces of the springs and the air pressure.

解释：空气制动其实包含三套系统：行车制动、驻车制动与紧急制动。 / EXPLANATION: Air brakes are really three different braking systems: service brake, parking brake, and emergency brake.

解释：所有空气制动车辆都有与储气筒相连的压力表，用来显示储气筒中的气压。 / EXPLANATION: All vehicles with air brakes have a pressure gauge connected to the air tank, and it tells you how much pressure is in the air tanks.

解释：1998 年 3 月 1 日及以后生产的转换拖架必须配备 ABS，并在左侧装有一个黄色指示灯。 / EXPLANATION: Converter dollies built on or after March 1, 1998, are required to have antilock brakes. These dollies will have a yellow lamp on the left side of the dolly.

解释：在气压充满后，熄火、释放驻车制动并计时气压下降。单一车辆在释放行车制动时，每分钟泄漏应小于 2 psi；在踩住制动时，每分钟泄漏应小于 3 psi。 / Right! EXPLANATION: With a fully-charged air system, turn off the engine, release the parking brake, and time the air pressure drop. The loss rate should be less than two psi in one minute for single vehicle brakes released, and three with the brakes applied.

解释：有些车辆仪表台上有一个手柄，可**逐步**施加弹簧制动，称为“调制阀”。它带弹簧阻尼，可提供脚感；你把手柄推得越多，弹簧制动施加得越重。若行车制动失效，可用它来控制制动。 / Correct! EXPLANATION: In some vehicles, a control handle on the dash board may be used to apply the spring brakes gradually. This is called a modulating valve. It is spring loaded, so you have a feel for the braking action. The more you move the control lever, the harder the spring brakes come on. They work this way, so you can control the spring brakes if the service brakes fail.

解释：在正常行驶中，踩下踏板时施加并释放制动的是行车制动系统。 / EXPLANATION: The service brake system applies and releases the brakes when you use the brake pedal during normal driving.

解释：无论是牵引车-挂车还是单一车辆，测试弹簧制动自动介入的方法与测试低气压报警类似：反复踩放制动踏板，这次要降到更低的气压，直到驻车制动阀关闭或弹出。 /  EXPLANATION: On both tractor-trailers and single vehicles, to test whether the spring brakes will come on automatically, use the same method you use for testing the low air pressure warning signal: Step on and off the brake pedal, this time until you reach an even lower psi reading and the parking brake valve closes or pops out.

解释：频繁使用制动、未依赖发动机制动会产生过多热量引起衰退；制动调整不当也会加剧衰退或导致失效。 / EXPLANATION: Brakes can fade or fail from excessive heat caused by using them too much and not relying on the engine braking effect. Brake fade is also affected by adjustment.

解释：在长陡下坡上，脚刹只应作为发动机制动的补充。 / EXPLANATION: The use of brakes on a long and/or steep downgrade is only a supplement to the braking effect of the engine.

正确！解释：当你踩下制动踏板，空气会进入每个制动室。 / Right! EXPLANATION: When you push the brake pedal, air is let into each brake chamber.

解释：陡坡下行应使用“缓压/点刹（snub）”法：施加足够的制动让车速明显下降；当速度降至比“安全速度”低约 5 mph 时松开刹车；当车速回到“安全速度”时重复。 / EXPLANATION: Snub braking method is used for steep downhill grades, in this method apply the brakes just hard enough to feel a definite slowdown. When your speed has been reduced to approximately five mph below your "safe" speed, release the brakes. When your speed has increased to your "safe" speed, repeat.

解释：在一些车辆上，仪表台的控制手柄可逐步施加弹簧制动，称为调制阀。它有弹簧回馈，手感清晰；手柄推得越多，弹簧制动施加得越重。 / EXPLANATION: In some vehicles a control handle on the dash board may be used to apply the spring brakes gradually. This is called a modulating valve. It is spring-loaded, so you have a feel for the braking action. The more you move the control lever, the harder the spring brakes come on.

解释：安全泄压阀装在压缩机首先充气的储气筒上，通常设定在 **150 psi** 打开，用以保护储气筒及系统免受过压；若阀门泄气，说明系统有故障，应检修。 / EXPLANATION: A safety relief valve is installed in the first tank the air compressor pumps air to. The safety valve protects the tank and the rest of the system from too much pressure. The valve is usually set to open at 150 psi. If the safety valve releases air, something is wrong. Have the fault fixed by a mechanic.

解释：低气压警报亮起，应尽快安全停车并靠边。 / EXPLANATION: If the low air pressure warning comes on, stop and safely park your vehicle as soon as possible.

解释：在气压充满后，熄火、释放驻车制动并计时气压下降。单一车辆在释放行车制动时，每分钟泄漏应小于 2 psi；在踩住制动时，每分钟泄漏应小于 3 psi。 /  EXPLANATION: With a fully-charged air system, turn off the engine, release the parking brake, and time the air pressure drop. The loss rate should be less than two psi in one minute for single vehicle brakes released, and three with the brakes applied.

解释：双回路系统是两套独立的空气制动共用一套操控；通常一套管后桥，另一套管前桥（有时也管部分后桥）。失压的那套对应车轴的常用制动将无法完全工作。 / EXPLANATION: A dual air brake system has two separate air brake systems, which use a single set of brake controls. Each system has its own air tanks, hoses, lines, etc. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle and possibly one rear axle.

解释：空气制动实际上包含三套系统：行车制动、驻车制动与紧急制动；无线电通信系统不属于空气制动系统。 / EXPLANATION: Air brakes are really three different braking systems: service brake, parking brake, and emergency brake.

解释：当你踩下空气制动，系统通过一个由气压驱动的**电开关**点亮刹车灯，以警示后方车辆。 / Right! EXPLANATION: Drivers behind you must be warned when you put your brakes on. The air brake system does this with an electric switch that works by air pressure. The switch turns on the brake lights when you put on the air brakes.

解释：警报失灵时，气压丢失你可能毫无察觉：在单回路系统中可能触发突然的紧急制动；在双回路系统中则制动距离会变长，弹簧制动很快介入，能用的制动十分有限。 / EXPLANATION: If the warning signal doesn't work, you could lose air pressure and you would not know it. This could cause sudden emergency braking in a single-circuit air system. In dual systems the stopping distance will be increased. Only limited braking can be done before the spring brakes come on.

解释：高温会使制动衬片发生化学变化而降低摩擦，同时会使制动鼓热膨胀，引发制动衰退。 /  EXPLANATION: Brake fade results from excessive heat causing chemical changes in the brake lining, which reduce friction, and also causing expansion of the brake drums.

解释：所有配有空气制动的车辆都装有与储气筒相连的压力表。若为双回路系统，则每个回路各有一块压力表。 / EXPLANATION: All vehicles with air brakes have a pressure gauge connected to the air tank. If the vehicle has a dual air brake system, there will be a gauge for each half of the system.

解释：切勿在未拉好驻车制动或未垫轮挡的情况下让车辆无人看管，否则车辆可能溜走并造成人身伤害或财产损失。 / EXPLANATION: Never leave your vehicle unattended without applying the parking brakes or chocking the wheels. Your vehicle might roll away and cause injury and damage.

解释：在储气筒靠压缩机的一侧装有单向止回阀，只允许空气进入储气筒，不允许回流到压缩机侧。 / EXPLANATION: Installed on the compressor side of the air tank is a one-way check valve, it allows air into the tanks, but does not allow it to flow back to the compressor.