雅思阅读：Difference Engine: Volt farce_雅思英语阅读

雅思阅读：Difference Engine: Volt farce

　　The trouble all started in May, when the National Highway Traffic Safety Administration carried out a routine 20 mph crash test on a Voltto simulate a sideways impact with a tree or telegraph pole followed by a rollover. Three weeks after the test, the cars 16 kilowatt-hour battery pack caught fire in NHTSAs car park, destroying the vehicle and several others nearby.

　　Shortly thereafter, both NHTSA and the carmaker repeated the side-impact and rollover test on at least two other cars, all to no effect. However, in subsequent testscarried out in November by experts from the energy and defence departments as well as GMthe investigators deliberately damaged the battery packs and ruptured their coolant lines. One battery pack behaved normally. Another emitted smoke and sparks hours after it was flipped on its back. And a third exhibited a temporary increase in temperature, but then burst into flames a week later.

　　GM claims the initial fire in June would never have happened if the NHTSAs engineers had drained the Volts battery immediately after the impact. It is odd that they did not. When crash testing a conventional petrol-powered car, the standard procedure is to drain the fuel tank to prevent any chance of fire. It would seem reasonable to do the equivalent with an electric vehicle.

　　But, then, GM did not adopt a depowering protocol for the Volt until after the June fire. Even when it did, it failed to share the procedure with the safety agency until embarking on the November tests. In the wake of the latest findings, GM is now working with the Society of Automotive Engineers, NHTSA and other vehicle manufacturers, as well as fire-fighters, tow-truck operators and salvage crew, to implement an industry-wide standard for handling battery-powered vehicles involved in accidents.