Scientific paper ID 1679 : 2018/3

The current work presents a comparative research of the internal and external instability of four, five and six cylinder piston engines with internal combustion. Gas forces and inertial forces are a theoretical definition coming from ascending moving masses as well as caused by their power torque, reactive moments and moments of inertial forces, acting on the engine housing at maximum fuel feed. For this purpose are tested small engines with a power of 60 kW which have the same construction parameters (piston diameter, traction volume, compression ratio, etc.) and operates in the same mode. The is a singular difference is the number of cylinders. The purpose of the development is to studies odd number of cylinders, and define the metrics as: inertial force as a function of crankshaft rotation, indicator diagram (p-V diagram), gas force as a function of crankshaft rotation, power torque is set one degree by the angle of rotation of the crankshaft rotation. Changing the number of cylinders also results in changing the angle between two successively operating cylinders, as for five-cylinder piston engines this angle is 1440. Determination of power torque the timing of the selected engines makes it possible to compare, evaluate and analyze the vibrational state of the five-cylinder, compared to the other two engines, respectively four-cylinder and six-cylinder.