【单选题】
AirBag
An air bag is an inflatable cushion designed to protect automobile occupants from serious injury in the case of a collision. The air bag is part of an inflatable restraint system, also known as an air cushion restraint systemACRS) or an air bag supplemental restraint system (SRS), because the air bag is designed to supplement the protection offered by seat belts. Seat belts are still needed to hold the occupant securely in place, especially in side impacts, rear impacts, and rollovers. Upon detecting a collision, air bags inflate instantly to cushion the exposed occupant with a big gas-filled pillow.
A、typical air bag system consists of an air bag module, crash sensors, a diagnostic monitoring unit, a steering wheel connecting coil, and an indicator lamp.
These components are all interconnected by a wiring harness and powered by the vehicle’s battery.
Air bag systems hold a reserve charge after the ignition has been turned off or after the battery has been disconnecteD、
Since components vital to the system’s operation might sit dormant for years, the air bag circuitry performs an internal "self-test" during each startup, usually indicated by a light on the instrument panel that glows briefly at each startup.
The air bag traces its origin to air-filled bladders outlined as early as
1941 and first patented in the 1950s.Early air bag systems were large and bulky, primarily using tanks of compressed or heated air, compressed nitrogen gas (N2), freon, or carbon dioxideCO2). Some of the early systems created hazardous byproducts. One particular system used gunpowder to heat up freon gas, producing phosgene gasCOCl2)--an extremely poisonous gas.
One of the first patents for automobile air bags was awarded to industrial engineer John Hetrick onAugust 18, 1953.Conceived by Hetrick after a near accident in 1952, the design called for a tank of compressed air under the hood and inflatable bags on the steering wheel, in the middle of the dashboard, and in the glove compartment to protect front seat occupants, and on the back of the front seat to protect rear seat passengers. The force of a collision would propel a sliding weight forward to send air into the bags. Many other inventors and researchers followed suit, all exploring slightly different designs, so that the exact technical trail from the early designs to the present system is impossible to note with certainty.
In 1968, John Piet, a chemist for TalleyDefense Systems, pioneered a solid propellant using sodium azide (NaN3) and a metallic oxide. This was the first nitrogen-generating solid propellant, and it soon replaced the older, bulkier systems. Sodium azide in its solid state is toxic if ingested in large doses, but in automotive applications is carefully sealed inside a steel or aluminum container within the air bag system. Since the 1960s, air bag-equipped cars in controlled tests and everyday use have demonstrated effectiveness and reliability. The Insurance Institute for Highway Safety conducted a study of the federal government’s FatalAccident Reporting System using data from 1985 to 1991, and concluded that driver fatalities in frontal collisions were lowered by 28 percent in automobiles equipped with air bags.According to another study conducted in 1989 by General Motors, the combination of lap/shoulder safety belts and air bags in frontal collisions reduced driver fatalities by 46 percent and front passenger fatalities by 43 percent.
In response to consumers’ increased safety concerns and insurance industry pressure, the federal government has forced
网考网参考答案：C
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An air bag is an inflatable cushion designed to protect automobile occupants from serious injury in the case of a collision. The air bag is part of an inflatable restraint system, also known as an air cushion restraint systemACRS) or an air bag supplemental restraint system (SRS), because the air bag is designed to supplement the protection offered by seat belts. Seat belts are still needed to hold the occupant securely in place, especially in side impacts, rear impacts, and rollovers. Upon detecting a collision, air bags inflate instantly to cushion the exposed occupant with a big gas-filled pillow.
A、typical air bag system consists of an air bag module, crash sensors, a diagnostic monitoring unit, a steering wheel connecting coil, and an indicator lamp.
These components are all interconnected by a wiring harness and powered by the vehicle’s battery. Air bag systems hold a reserve charge after the ignition has been turned off or after the battery has been disconnecteD、 Since components vital to the system’s operation might sit dormant for years, the air bag circuitry performs an internal "self-test" during each startup, usually indicated by a light on the instrument panel that glows briefly at each startup. The air bag traces its origin to air-filled bladders outlined as early as
1941 and first patented in the 1950s.Early air bag systems were large and bulky, primarily using tanks of compressed or heated air, compressed nitrogen gas (N2), freon, or carbon dioxideCO2). Some of the early systems created hazardous byproducts. One particular system used gunpowder to heat up freon gas, producing phosgene gasCOCl2)--an extremely poisonous gas.
One of the first patents for automobile air bags was awarded to industrial engineer John Hetrick onAugust 18, 1953.Conceived by Hetrick after a near accident in 1952, the design called for a tank of compressed air under the hood and inflatable bags on the steering wheel, in the middle of the dashboard, and in the glove compartment to protect front seat occupants, and on the back of the front seat to protect rear seat passengers. The force of a collision would propel a sliding weight forward to send air into the bags. Many other inventors and researchers followed suit, all exploring slightly different designs, so that the exact technical trail from the early designs to the present system is impossible to note with certainty.
In 1968, John Piet, a chemist for TalleyDefense Systems, pioneered a solid propellant using sodium azide (NaN3) and a metallic oxide. This was the first nitrogen-generating solid propellant, and it soon replaced the older, bulkier systems. Sodium azide in its solid state is toxic if ingested in large doses, but in automotive applications is carefully sealed inside a steel or aluminum container within the air bag system. Since the 1960s, air bag-equipped cars in controlled tests and everyday use have demonstrated effectiveness and reliability. The Insurance Institute for Highway Safety conducted a study of the federal government’s FatalAccident Reporting System using data from 1985 to 1991, and concluded that driver fatalities in frontal collisions were lowered by 28 percent in automobiles equipped with air bags.According to another study conducted in 1989 by General Motors, the combination of lap/shoulder safety belts and air bags in frontal collisions reduced driver fatalities by 46 percent and front passenger fatalities by 43 percent.
In response to consumers’ increased safety concerns and insurance industry pressure, the federal government has forced
网考网参考答案：C
网考网解析：
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