Research On A Hydraulic-driven Continuously Variable Valve Technology For SI Engine

Valve train is one of the important systems of the engine which through the valve lift, valve timing and valve opening duration and other parameters affect the performance of engine. The structural parameters of traditional engine valve train are not adjustable. That is to say. through it can satisfy the engine to achieve optimal regional performance in a narrow working conditions, it can not fully take the performance of the engine operating conditions into account. Such as calibration of the speed conditions and so on. Generally speaking, the engine’s performance is poor when it in low-speed and small and medium load region, while for the motor vehicle, the above range is a common engine performance region. Because of this, the related engine manufacturers and the majority of researchers launched the study of to broaden the range of optimal parameters of the valve train. The variable valve timing technology was carried out in this context, which become the research hot spot prevalently in nearly20years.Because of the defects of the traditional valve’s unadjusted parameters, this paper which on the basis of previous experience, it presents a continuously variable valve timing technology based on the hydraulic-driven engine.It uses two-spot parameter control measures. That is. it controls the valve lift and phase at the same time, and make it varies continuously according the actual conditions of the engine. The paper revolutionary adopts the Physiognomy cam and Phase modulation cam to control the phase of the valve timing and its duration and learns from the fuel supply regulating principle to control the valve lift. It gets through the organic combination of the two parameters to achieve the engine valve continuously adjustable, thus enriching the engine variable valve timing technology.The paper’s main contributions and job performances are in the following respects:1. Firstly, the paper proposes principle and implementation method of engine continuously variable technology based on Physiognomy cam and Phase modulation cam, and it achieved the early intake valve open-angle and the night off angle. It also laid the foundation of broadening the scope of the adaptation of the engine intake system.2. Secondly, the paper references the structure and principle of mutative oil amount output for diesel oil-supply device, applied in the adjusting mechanism of the valve lift, and using the hydraulic oil as power of driving valve-opening, and realizing continuous stepless adjustable from the zero trip to the largest lift for valve lift, which provides design engine based for developing the engine without throttle valve.3. Besides, the paper establishes mathematical model of continuously variable valve gas distribution device tor the new engine. It analyses the geometric, kinematic and dynamic characteristics of the new valve train based on the MATLAB engineering software. Theoretically, it discussed the control characteristics and laws of the new device.4. Finally, the paper also combined a particular model of motorcycle engine to gives its specific implementation routes and programs which including overall layout of valve, structural design, control methods and attention details and so on.