汽车专业英语课件与汽车专业英语读译教程2版配套5U3TB.pptVIP

UNIT3 FUEL INJECTION SYSTEMS TEXT BFunctions of the Motronic Systems  UNIT 3 FUEL INJECTION SYSTEMSTEXT BFunctions of the Motronic Systems ? Ignition Timing Control? Control Unit ? Dwell-Angle Control ? Idle Speed Control  本次课学习目标 掌握Motronic系统的主要功能及其作用原理 掌握常用术语 了解相关术语 提高翻译能力 NEW WORDS · Many additional operating functions can be provided. Important from the standpoint of service are the adaptive functions, and the self-diagnostics for troubleshooting · Motronic advantages are better driveability and fuel efficiency, and reduced emissions. More specific benefits: a. fuel savings achieved from best combination of mixture and timing b. dependable starting, cold or hot c. stable idling at reduced rpm e. relative freedom from maintenance f. good torque characteristics, allowing longer gear ratios Ignition Timing Control Im talking here about more than electronic ignition-the systems that have replaced the points and condensers of yesterday. Im talking about microcomputer control of ignition advance angle for every plug firing, or at most, every two plug firings. The millisecond response time of electronic ignition advance control is far faster than the traditional mechanical flyweight/vacuum advance systems. In a mechanical system (and that includes electronic ignition), as rpm increases, centrifugal weights advance timing. Changing load (manifold pressure) can further change timing advance with a vacuum diaphragm. As rpm increases, there is less dwell time for the coil to charge when perhaps the engine needs more spark energy. Traditional curves for distributor timing show the limited control of timing advance possible. A timing point that is proper for one combination of rpm and load is probably wrong for other combinations of centrifugal weight position and vacuum diaphragm action. Once the vacuum control or the centrifugal weights reach their limits, advance control is fixed. Mech