Dynamic model of a two-cylinder four-stroke internal combustion engine and vibration treatment

Abstract

Engine vibrations of large amplitude are caused by inertial effects of the piston–crankshaft mechanism and gas forces, and are transmitted to the chassis of a vehicle in the form of periodically varying forces through the engine mounts. Both the engine vibrations and mount forces may be minimized by designing proper engine components and mounts, which requires a dynamic simulation of the engine. In this study, a three degree of freedom dynamic model, enabling the simultaneous treatment of the piston–crankshaft mechanism and engine block, was devised for a two-cylinder four-stroke engine. Periodic and temporary variations of crankshaft speed, the variation of torque and power with speed, torsional and translational vibrations of the engine block, and the variation of mount forces with respect to the damping and stiffness coefficients of the mounts were studied. The torsional and translational vibrations of the engine block were found to be mainly affected by the combustion gas force and inertia force of the reciprocating masses, respectively. A simple relation has been obtained to determine the position and mass of counterweights used for eliminating the vertical vibration of the block.

Studi Numerik Respon Getaran Mesin Bensin Dua Silinder Segaris Dengan Variasi Sudut Antar Engkol

“…Karabulut [3] melakukan penelitian getaran dengan membuat model dinamis tiga derajat kebebasan dari mesin pembakaran dalam empat langkah dua silinder. Simulasi dilakukan dengan variasi kecepatan poros engkol, variasi torsi dan daya dengan kecepatan, getaran torsional dan translasi dari blok mesin, dan variasi gaya dudukan dengan koefisien redaman dan kekakuan dari dudukan.…”

Design of the multi-cylinder Stirling engine arrangement with self-start capability and reduced vibrations

“…In addition, the Stirling engines vibrations can be reduced by methods of reducing the charge pressure or dynamic balancing which adds counterweights to the crankshaft [16] [17]. Dynamic balancing can effectively remove vertical vibrations but creates horizontal vibrations hence there will be a need to reduce the reciprocating masses [18] [19].…”

Benzin ve Dizel Motorlarda Devir Sayısının Titreşime Olan Etkisinin İncelenmesi/Investigation of the Effect of Revolution of Diesel and Gasoline Engines on Their Vibration

“…Ayrıca taşıttaki titreşimler, taşıt üzerindeki sistemlerin darbelere, malzeme yorgunluğuna, sürtünmelere ve ısıl gerilmelere maruz kalmalarına ve kısa sürede arızalanmalarına neden olabilir. Malzeme yorgunluğuna bağlı arızalanmalar, titreşimin en önemli sonuçları arasında yer almaktadır [3,4].Titreşimin azaltılması gürültü miktarını da yaklaşık iki kat kadar azaltmaktadır [5]. İçten yanmalı motorlarda oluşan titreşimlerin temel sebepleri; yanma sonucu oluşan değişken gaz kuvvetleri, ivmeli hareket yapan motor parçalarının balanssızlığı, volanın meydana getirdiği merkezkaç kuvveti ve supap mekanizmasındaki geçici rejim etkileşimleridir [6,7].İvmeli doğrusal ve döngüsel hareket gerçekleştiren parçalar ile balanslanmamış kütlelerin yarattığı zorlama kuvvetleri, harmonik motor frekanslarının tam katlarını meydana getirirler.…”