Investigate On VVT System Based On Diesel Fuel

Variable valve timing systems, without cam and electronically controlled hydraulically actuated, have no limitation of traditional valve camshaft, whose valve lift and valve timing profile are independent on the cam profile. The system can achieve the adjustment of the valve timing, valve lift, valve open period and other parameters according to the respective operation conditions of ICE. These further lead to the improvement of the ICE performance.By analyzing and comparing several kinds of domestic and international advanced electronically controlled variable valve timing and lift systems, on the basis of the working principle and design features of high pressure common rail diesel injection system, a new kind of variable valve timing and lift system is developed in this paper, with the features that:no change to the structure of the cylinder head, no impact on the injector or other components in the installation on the cylinder head; fuel as the working fluid, fuel pump as high pressure oil source, complete the design of valve actuation mechanism according to the principle of electronic fuel injector; Solenoid valve being placed on the top of valve driving mechanism, which saves the installation space; smaller volume, contributing to the layout on the cylinder head.Engine performance simulation model, which is built using the engine performance simulation software GTPOWER, predicts the velocity characteristics of variable valve timing parameters (such as the valve lift, the intake valve opening and closing angle, the exhaust valve opening and closing angle, valve overlap angle, etc), and shows the need of the research to variable valve timing technology. The paper designs a suit of variable valve timing system, including the hydraulic driving system,variable valve actuator system, and electronic control units system etc. And the system, instead of cam actuated valve timing system, is installed on the cylinder heads of 4102BG diesel. According to the features of electro-hydraulicly driven variable valve timing system, the simulation model is built using AMESim software. The studies on the main structure parameters of the system, such as piston diameter, spring rigidity of the valve,flow area of electro-magnetic valve and common rail volume, obtain the characteristics of the variable intake valve system.Both the model and this studies speed up the development processes,thus minimizing the number of hardware variations.