Design of the Engine Timing Silent Chain System Based on the Pitch-variation Algorithm

Abstract

Based on a timing silent chain system in two-axle type engines, the mathematical model of the correct ideal chain path was established, and an algorithm for automatically computing the radius of the loose side or tension side chain and its corresponding wrap angle was presented. According to the requirements about encircling the chain, a new method to design the timing silent chain system in engine based on the pitch-variation algorithm was proposed. Compared with the classical method, the new method does not need the help of the CAD software for secondary design and multiple adjustment, and the design results are more in line with the design requirements, which is a parametric design method in the standard sense. By using the secondary development of the CAE software, a multi-body dynamics model of the timing silent chain system was generated in real time, and the chain link track, the tension force between chain links, and the tensioner vibration in the system designed by the new method were analyzed at different speeds. The results show that, for the new design method proposed, the transmission stability and high-speed characteristics are good, the system matching degree and the chain wear resistance are excellent, and the tension force between chain links is stable, so the design requirements can be met. This method is also suitable for the other types of the engine timing system.

Keywords

• Timing system
• Silent chain
• Pitch-variation algorithm
• Parametric design
• Multi-body dynamics