Khoo Wee Chern

Using Visual Basic to Simulate Engine Dynamics

By Khoo Wee Chern, March 13, 2019

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Using Visual Basic to Simulate Engine Dynamics
This is a course called 'Machine Dynamics' in university. It uses force analysis to coding prototype of application and simulates the influence of engine mass and moment of inertia which is used as a design or tuning engine of reference. (This is assignment of class) State 1: Setting the 3 masses of piston rod tom2=3, m3=2, m4=1, the moment of inertia I2=0.08, I3=0.02, I4=0.05. Press Start to full throttle, you can see the RPM rising quickly but the moment of inertia are too weak causing the engine RPM to be unstable and the wheel speed will be 'one fast one slow', the car is difficult to drive. State 1 video link: https://drive.google.com/file/d/1E079tMVAn8JAGDEIliBUFoI7hQzfOgkM/view?usp=sharing State 2: Increase mass and moment of inertia, which is m2=9, m3=8, m4=7, moment of inertia I2=6, I3=5, I4=4. Press 'Start' to full throttle, the RPM is rising slowly but the engine RPM is much stable and the vibration of indicator becomes much smaller.The wheel speed will be more stable but the acceleration of the car will be poor relatively. State 2 video link: https://drive.google.com/file/d/1dBp2OQtFInGUQ1FdFt3tQui47i15Siwu/view?usp=sharing Conclusion: Through the simulating of engine dynamics, it can be seen that the mass and moment of inertia of piston rod set and flywheel will affect the engine work. Generally, car factory are trying to reduce the mass of piston rod set to achieve weight reduction(To accelerate RPM).Increase the counterweight of flywheel at the crankshaft end to enhance moment of inertia and to stabilize the RPM.It has to set the ignition time of each cylinder to balance the impact of piston movement. However, this processing is not accurately enough cause the deviation of result is larger. The assignment of simulate engine dynamics(including force analysis and coding but Chinese ver. only):https://drive.google.com/file/d/1knDNKPM_34uwjop9mgOAGerALs6Ed-Yx/view?usp=sharing

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