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ㆍProduct: Engine valve

ㆍ Analysis Goal :  To reduce the carbon deposits around the engine inlet ports

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A scooter manufacturer desires to reduce engine failure by reducing carbon deposits around the inlet ports.The inlet valves are designed to be rotated by the camshaft movement when they are opened to prevent the buildup of carbon. At high rpm, the valves rotate well.

However, at low rpm, the valves do not rotate adequately to prevent carbon build-up. As a result, under low rpm use, there can be significant carbon deposits around the inlet ports, which can lead to engine failure.

RecurDyn was used to identify that valve contact surface shape is the key to trigger valve rotation. Then RecurDyn was used to design and validate a different, improved valve contact surface shape that can enabled sufficient valve rotation even at low rpm to prevent carbon deposits from forming.

Process

① Created an MBD model including contact, springs, and cam to reproduce and validate the valve rotation

② Ran simulations at various rpm of interest

③ Analyzed the valve rotation at different speeds

④ Analyzed the valve rotation with different valve contact surface shapes

Key Technologies for Analysis

• Rigid multi-body dynamics used to quickly perform multiple simulations with different shape and rpm

• Nonlinear contact algorithm to calculate the contact forces between complex geometries quickly and accurately

• Trajectory display to visually verify the rotational motion of the valves

Toolkits

• RecurDyn/Professional

Customer Challenges

• Trial & error using physical prototypes requires more than half a year to achieve design improvement.

• Measuring and monitoring the valve rotation using experiments is very difficult.

• Complex contact behavior is not supported with traditional CAD software.

• Valve contact surface shape improvement must be achievable with reasonable time and cost.

Solutions

• Fast modeling and simulation using professional dynamics software

• Fast and accurate simulation using powerful contact algorithm

• Simple and convenient visualization of results compared to cumbersome measurement and monitoring of physical experiments

• Quantitative evaluation of the effect of contact surface shape and visual verification of valve rotation through trajectory display

Outcomes

• RecurDyn correctly recreated valve rotation for various camshaft rpm

• The new valve contact surface shape was validated using simulation

• Simulation results provided guidance for further design improvements for the new engine

Other Applications

◀ Analysis of a Gear Train

ㆍDynamic analysis of gears that are represented as flexible bodies

ㆍAnalysis of transmission to check contact force as a function of the shape of gear teeth

◀ Transmission Simulation Using RecurDyn

ㆍDynamic simulation of transmission with multiple gears

ㆍAnalysis of gears’ dynamic behavior when shifting gear

◀ Animation of Engine Valve