Valve spring design steps

The design of valve springs is a key link in the engine valve mechanism and plays a vital role in ensuring the efficient and stable operation of the engine. A good valve spring design can not only effectively prevent valve fly-off, but also reduce friction and wear of the valve mechanism, improving the overall performance and life of the engine. The following is a detailed and expanded description of the valve spring design steps
(1) Step 1 By analyzing the vehicle's downhill driving performance and engine braking, the valve mechanism's fly-off speed design target is determined to determine the required valve spring preload and spring stiffness;
(2) Step 2 Establish a valve mechanism dynamics model to accurately predict fly-off and evaluate the effect of in-cylinder recompression pressure on fly-off;
(3) Step 3 By performing parameter sweep calculations for different values ​​of spring preload and spring stiffness, a parameter diagram of the valve mechanism dynamics is constructed to examine their effects on the valve mechanism vibration. It is necessary to plot the push rod force, valve train acceleration and spring deceleration against the crankshaft angle in the figure to show the design margin for flyaway, so that the target values ​​of spring preload and spring stiffness can be conveniently and wisely selected in step 4;
(4) Step 4 calculates the required spring preload based on the static force balance of the exhaust valve head to prevent exhaust valve jump. Select the exhaust valve spring preload for engines with and without exhaust brakes, and use the design parameter diagram in step 3 to select the matching spring stiffness;
(5) Step 5 performs parameter sweep calculations on the design parameters and uses graphical design methods to construct parameter sensitivity design diagrams for spring design. Select the average spring diameter, coil wire diameter and number of coils while satisfying the design constraints such as spring torsional stress, natural frequency, and coil gap. Alternatively, the analytical optimization method can be used to directly solve the formula.
Valve spring design is a multi-variable, multi-constrained system engineering that requires comprehensive consideration from multiple perspectives such as flyaway performance, dynamic model, static mechanics, material mechanics, and actual working conditions. Scientific and reasonable design processes and advanced modeling and analysis technologies can not only improve spring performance, but also effectively extend engine life and improve vehicle power performance. With the improvement of computing power and the development of materials science, the design of valve springs will become more intelligent and refined in the future, helping engines to develop in a more efficient and environmentally friendly direction.