| Summary: | 碩士 === 國立臺北科技大學 === 車輛工程系所 === 100 === An engine that with variable valve lift system for Throttleless Scooter not only reduce fuel consumption efficiently, but also increase engine efficiency. The scooters selling in the market currently are needed to use a throttle to control the intake flow, the intake valve is also fixed lift. The proposed hydraulic control of the variable valve lifts system is different from the traditional scooters intake manner. Instead of using throttle to regulate the intake air, the inlet valve achieves an effect upon continuous variable by hydraulic control which according to driver''s need. At first, the study uses a bench to measure the profile of intake valve to confirms the profile is the same with the original engine, and further to start the engine for engine experiment to compare the differences in pumping loss and fuel consumption. The comparison is based on the ECE-40 driving pattern which the velocity is in the steady-state interval, and using this engine speed and crankshaft output torque to do the experiment. The results show that the hydraulic-controlled variable valve lift system can improve the pumping loss about 12.18%~20.75%, and also reduce the fuel consumption about 4.97% ~ 6.97%. The proposed system is finally installed in the scooter and to do different velocity under the constant speed test on a chassis dynamometer. The test results of the fuel economy in terms of distance traveled per unit of fuel has improved by 2.96 ~ 8.35%.
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