汽车英语的重要性论文题目

-- Scott Perl, Albuquerque, . A: Auto racers have told us the main advantage in filling tires with nitrogen instead of ambient air is that nitrogen tends to maintain more consistent tire pressure over a wide range of temperatures. As friction between the tire and pavement drives up the temperature, air with varying amounts of moisture content responds differently and can cause inconsistencies in tire pressure. While racing drivers are more likely to notice the advantages of nitrogen than everyday drivers, we haven't heard of any disadvantages to using it. Skeptics question the practice, noting that ambient air is about 80% nitrogen and that it expands and contracts at the same rate as pure nitrogen. A number of readers say there's no appreciable difference in how the tires will react if filled with nitrogen, especially in everyday use. Q: Is it safe to use cruise control in rain or on wet pavement? -- Scott Brake, Westminster, Calif. A: Car makers often warn that cruise control should be used only in light traffic on open roads and in good weather. There have been reports of accidents involving cruise control when the car lost traction -- or hydroplaned -- in slippery conditions. Some car makers warn that the steady throttle of cruise control -- like keeping one's foot on the gas -- could cause the wheels to spin when they hit a wet or icy patch of road. Car-company representatives say the cruise- control warnings reflect the fact that drivers should be particularly vigilant when conditions are less than ideal, and cruising along on what amounts to partial autopilot tends to lull some drivers into a false sense of security. Q: If an automobile manual suggests a certain weight oil (such as, 5W-30), would adding a quart of a different weight oil (say, 10W-40) between complete oil changes damage the car's engine? -- Gil Ehrenkranz, Potomac, Md. A: Probably not. But today's engines generally are more precisely engineered than those of 20 or 30 years ago. Many of us at some point have topped off our cars with whatever oil happened to be available without causing damage -- at least not that we know of. Auto makers, however, say modern engines can be more sensitive to a change in oil weight, and using the wrong oil, even in small amounts, can hurt an engine's performance and even cause harm. Q: What is a sequential manual transmission? How does it differ from an automatic or a standard manual transmission? -- Harry J. Jaffe, Germantown, Tenn. A: A sequential manual transmission is a gearbox that requires gear changes to be made in order (first to second to third), instead of having a shift pattern with a lever that allows the driver to skip gears. Motorcycles have used such transmissions for decades and racing cars began using them years ago because they allow quicker shifts. Shifting is usually done through levers, buttons or switches. The sequential transmissions advertised today -- mainly in high- performance cars such as Ferraris, Aston Martins and some BMWs -- are technically manual transmissions, except that the clutch and the gear changes are controlled electronically. The advantage is that gear changes can be made more quickly and precisely than a human shifting the old-fashioned way. Traditionalists say the downside is that they simply aren't as much fun to drive and require less driver skill.