Marked Progress in Both Technique and Handling of Valve Train and Valve Train Drive Calculation on Commercial Platforms 1999-01-0560

In recent years, the design and development of combustion engines have been revolutionized by the use of computer simulation tools. These tools allow rapid dissemination of information about critical systems during the concept design phase, and also allow a high level of optimization within the total engine design process. The extended cooperation between manu-facturer and external engineering partner creates the necessity of a common access to the simulation tools for both parties.

At FEV several simulation programs have been developed [1, 2] that are used by specialists who are familiar with the specific program. Due to the frequent use of these tools in various projects [3, 4] their database is always up to date, they are continuously improved and the results are verified by measurements.

The simulation models for the dynamic calculations of valve train, as well as valve train drive systems, have been transferred to a commercially available multi-body-dynamic simulation software. The valve train and valve train drive models use a combination of standard elements. Models of a valve spring and the hydraulic adjusting element and tensioner have been taken over from their parent programs to the new platform. Once specific models are transferred to the platform, the tool offers tremendous opportunities. For example further physical properties can be added into each model, and user-defined routines can be integrated if the standard elements are not sufficient. By this procedure, models can be exchanged and steadily developed. Also the connection to F.E.A. calculation programs is enhanced.

The possibilities of extending the models allow the comprehensive simulation of complete valve train assemblies, complex valve train drive systems and their combination.

FEV's chain drive model takes the mass of each link of the chain into account. The system is driven by the crankshaft, and in the model the chain itself is dynamic. Geometric boundary conditions (pulley-chain, guide-chain) as well as tensioners (mechanical-hydraulic) can be modeled exactly.