A Novel Coaxial Balance Mechanism for Reciprocating Piston Engines

Abstract

Vibration is an important issue faced by reciprocating piston engines, and is caused by reciprocating inertia forces of the piston set. To reduce the vibration without changing the main structure and size of the original engine, we proposed a novel coaxial balance mechanism design based on a compact unit body. By introducing a second-order balance mass, this mechanism can significantly increase the efficiency of vibration reduction. The proposed mechanism can effectively balance the first-order and second-order inertia forces with the potential of balancing high-order inertia forces. To accurately determine the second-order balance mass, a closed-form method was developed. Simulation results with a single-cylinder piston DK32 engine demonstrate the effectiveness and advantage of the proposed mechanism. At a crankshaft speed of 2350 r/min, compared with the first-order balance device, the average root mean square velocity of the test points on the engine’s cylinder was reduced by 97.31%, and the support reaction force was reduced by 96.54%.

Hybrid methodology using balancing optimization and vibration analysis to suppress vibrations in a double crank-rocker engine

“…Generally, vibration could be suppressed practically by eliminating the source causing these vibrations, such applying balancing [7] or alignment [1] to rectify equipment problems. Another method is by isolating the vibratory element from the rest of the system by applying isolators such as mechanical shock dampeners, mechanical or hydraulic absorbers, or both depending on design aspects [17].…”

“…1 P is the space between both linkages, and 2 P is the distance between fixed joints. The resulting forces and moments are calculated in the local coordinate system and need to be transferred to the global coordinate system using the transformation matrix A used in (7) as follows:…”

“…Modes' participation magnitudes are also illustrated in Figure (7), where mobility response ϒ x is presented. This shows how each mode contributes to the overall peak frequencies, where six modes are contributing to the mobility response ϒ x.…”