外文资料原文Clutch Common ProblemsFrom the 1950s to the 1970s, you could count on getting between 50,000 and 70,000 miles from your cars clutch. Clutches can now last for more than 80,000 miles if you use them gently and maintain them well. If not cared for, clutches can start to break down at 35,000 miles. Trucks that are consistently overloaded or that frequently tow heavy loads can also have problems with relatively new clutches.The most common problem with clutches is that the friction material on the disc wears out. The friction material on a clutch disc is very similar to the friction material on the pads of a disc brake or the shoes of a drum brake - after a while, it wears away. When most or all of the friction material is gone, the clutch will start to slip, and eventually it wont transmit any power from the engine to the wheels.The clutch only wears while the clutch disc and the flywheel are spinning at different speeds. When they are locked together, the friction material is held tightly against the flywheel, and they spin in sync. Its only when the clutch disc is slipping against the flywheel that wearing occurs. So, if you are the type of driver who slips the clutch a lot, youll wear out your clutch a lot faster.Sometimes the problem is not with slipping, but with sticking. If your clutch wont release properly, it will continue to turn the input shaft. This can cause grinding, or completely prevent your car from going into gear. Some common reasons a clutch may stick are:Broken or stretched clutch cable - The cable needs the right amount of tension to push and pull effectively. Leaky or defective slave and/or master clutch cylinders - Leaks keep the cylinders from building the necessary amount of pressure. Air in the hydraulic line - Air affects the hydraulics by taking up space the fluid needs to build pressure. Misadjusted linkage - When your foot hits the pedal, the linkage transmits the wrong amount of force. Mismatched clutch components - Not all aftermarket parts work with your clutch. A hard clutch is also a common problem. All clutches require some amount of force to depress fully. If you have to press hard on the pedal, there may be something wrong. Sticking or binding in the pedal linkage, cable, cross shaft, or pivot ball are common causes. Sometimes a blockage or worn seals in the hydraulic system can also cause a hard clutch.Another problem associated with clutches is a worn throw-out bearing, sometimes called a clutch release bearing. This bearing applies force to the fingers of the spinning pressure plate to release the clutch. If you hear a rumbling sound when the clutch engages, you might have a problem with the throw-out.Clutch Diagnostic TestIf you find that your clutch has failed, here is an at-home diagnostic test that anyone can perform:1. Start your car, set the parking break, and put the car in neutral. 2. With your car idling, listen for a growling noise without pushing the clutch in. If you hear something, its most likely a problem with the transmission. If you dont hear a noise, proceed to step three. 3. With the car still in neutral, begin to push the clutch and listen for noise. If you hear a chirping noise as you press, its most likely the clutch release, or throw-out bearing. If you dont hear a noise, proceed to step four. 4. Push the clutch all the way to the floor. If you hear a squealing noise, its probably the pilot bearing or bushing. If you dont hear any noise during these four steps, then your problem is probably not the clutch. If you hear the noise at idle and it goes away when the clutch is pressed, it may be an issue in the contact point between the fork and pivot ball. BiomaterialsManufacturers are starting biomaterials to reduce CO2 emissions throughout the vehicles lifecycleManufacturers are starting to concentrate more closely on cutting carbon dioxide emissions from vehicles lifecycles. That means looking at the carbon dioxide production and disposal of the vehicle, not just the pollutants that come out of the tailpipe.European vehicle recycling laws are making carmakers that sell cars in Europe take more responsibility for the effect their vehicles Honda and Mitsubishi are the latest to develop new materials.Recycling the metal that makes up majority of the vehicle is not the hardest pert; the plastics plastics present a far greater challenge. Interiors pose a particular recycling problem as they use a lot of plastics.Honda has developed a plant-based fabric with excellent durability and resistance to sunlight for use a surface material in automobile interiors.Bio-fabrics are the most likely solution as they are derived from plants that absorb carbon dioxide ad they grow. When vehicle is scrapped and the fabrics incinerated, only some of the released carbon dioxide has come from a fossil source.Despite this benefit, plant-based fabrics have not yet been used