Ant Colony Optimization for the Minimization of Internal Combustion Engine Forces and Displacements
The unbalanced forces from the engine reciprocating and rotating component are the major contributors for the internal combustion engine vibration. The reciprocating and rotational inertial forces are modeled to determine the total forces excited and disp
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n The reasons for the internal combustion (IC) vibration are fluctuating forces at the skirt of the piston and at the reciprocating components [1]. Impact forces at piston, due to the unbalanced forces of the rotating and reciprocating parts, are the common impact phenomenon existing in the reciprocating IC engine. It also plays an important role in the transverse vibration of the engine [2]. In the crank and slider mechanism of the IC engine, the piston is driven by the cylinder gas pressure and moves inside the cylinder along with the connecting rod and the crankshaft [3]. At the same time the periodical changing of direction of the connecting rod leads to the variation of inertial force in the cylinder wall and crank shaft. The unbalanced forces from the piston and connecting rod setup create not only the variational T. Ramachandran (*) PSNA College of Engineering and Technology, Dindigul, Tamilnadu, India e-mail: [email protected] K. P. Padmanaban SBM College of Engineering & Technology, Dindigul, Tamilnadu, India e-mail: [email protected] J. Vinayagamoorthy Mechanical Engineering, PSNA College of Engineering and Technology, Dindigul, Tamilnadu, India e-mail: [email protected]
S. Sathiyamoorthy et al. (eds.), Emerging Trends in Science, Engineering and Technology, Lecture Notes in Mechanical Engineering, DOI: 10.1007/978-81-322-1007-8_2, © Springer India 2012
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impact force on the cylinder walls but also the variational speed fluctuation on the crank shaft. So, the cylinder block experiences the vibrational force due to the impact force by slap as well as the speed variation in the crank shaft. The solutions attempted to reduce the engine forces and displacements due to the diesel excitations are usually to isolate the engine from the vibratory forces. In this chapter, a 4-cylinder IC engine is considered as rigid body and the mathematical modeling is done to determine the forces and displacements exerted by the engine during the operation. Attempts are made to reduce the engine forces and displacements by optimizing the crank angles of the counter weights. Ant colony optimization [4] technique is used to predict the optimum positions of counter weights under minimum displacements at the engine supports.
2 Rigid Body Modeling of the Engine The engine vibration can be classified into two types: vibration of engine components with respect to each other, named as internal vibration, and the vibration of engine block as a total, named as external vibration. The unbalanced forces from the engine components lead to the external vibration [1]. To analyse the engine vibration the engine will be considered as rigid body with 6° of freedom in x, y and z axis about its centre of gravity [5]. Consider an engine as a rigid body of mass M connected to a rigid chassis by three rubber engine mounts, as shown in Fig. 1. The origin of the fixed global coordinate system is located at the center of mass of engine. The z-axis is parallel to the crank shaft, and the x-axis is in the v
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