Effect of Multi-Factor Coupling on the Movement Characteristics of the Hydraulic Variable Valve Actuation

Abstract

Studies show that the valve lift (VL) of the cam-driven hydraulic variable valve actuation (VVA) can be continuously adjusted in the range of 0–8.2 mm by controlling the opening of the throttling valve. In the present study, an orthogonal experiment with interaction was designed to analyze the effect of multi-factor coupling on the VL, valve-seating velocity (VSV), and pressure fluctuation in the valve piston cavity. In order to reduce the pressure fluctuation, the Taguchi method was applied to find the optimal combination of the key parameters including the diameter of the piston, the spring preload of the valve-seating buffer mechanism (VSBM), the spring preload of the valve, and the valve piston mass. The correctness of the VVA simulation model is verified through experiments. Moreover, the pressure fluctuation is analyzed through a numerical simulation. The obtained results showed that as long as the VSV is less than 0.5 m·s−1, the pressure fluctuations in hydraulic VVA can be reduced by several means, such as increasing the spring stiffness of the VSBM and valve, increasing the valve piston area and diameter size of the thin-walled hole, and reducing the valve piston mass and total hydraulic oil volume.

Keywords

• variable valve actuation
• multi-factor coupling
• hydraulic pressure fluctuation
• Taguchi method
• orthogonal design
• combustion engine