This diploma thesis deals with investigation of dynamic straining valve OHV for four-valve head diesel engine Zetor 1505 – 90 kW. The calculation is performed analytically in mathematic software MathCad and MBS software ADAMS/Engine 2005. Also in this diploma thesis is from results obtained from MBS system perfomed stressed analysis valve_rocker arm gear divorce method final elements (MKP) in program ANSYS 10.

Tomáš ŠTÁBL Design of Gear Timing Mechanism for SI Engine MT, IAE, 2009, 62 pp., 27 fig. This master thesis is concerning the valve train proposal of the spark ignition engine for sports purposes. Antecedent to the actual proposal is the division and retrieval of the modern valve trains, the valve train acting forces description, division and description of the individual valve-lift curve parts , valve springs and the dynamic models of the valve train. In the thesis there are designed the valve lift curves with the continuous course of acceleration, valve springs and valve springs natural oscillations damper for engine Honda CBR 929RR. The dynamic analysis of valve train approach is performed.

The widespread use of finite element models in assessing system dynamics for noise, vibration, and harshness (NVH) evaluation has led to recognition of the need for improved procedures for correlating models to experimental results. This study develops and applies a methodology to correlate an experimental modal analysis with a finite element modal analysis of valve trains in IC-engines. A pre-test analysis procedure is employed to guide the execution of tests used in the correlation process. This approach improves the efficiency of the test process, ensuring that the test article is neither under nor over-instrumented. The test-analysis model (TAM) that results from the pre-test simulation provides a means to compare the test and the model both during the experimental approach and during the model updating process. The validity of the correlation methodology is demonstrated through its application on the valve train of a single overhead cam (SOHC) engine.

Orientador: Katia Maria Lucchesi Cavalca / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T03:12:40Z (GMT). No. of bitstreams: 1 Mastaler_Alexandre_M.pdf: 8070977 bytes, checksum: 67729451cedeb65f0b15eb1a17a3fead (MD5) Previous issue date: 2004 / Resumo: O comando de válvulas é um sistema utilizado em motores à combustão, que tem como função controlar a abertura e fechamento de válvulas de circulação dos gases envolvidos na combustão. Ele é composto por diversos subsistemas; Um desses subsistemas é o contato balancim/pivô, onde o comando aciona o balancim para que esse acione a válvula e utilize o pivô como elemento de suporte. O conhecimento desse subsistema é importante para a avaliação de desgastes e ruídos provenientes desse contato, assim como, avaliações do atrito para otimização geral do comando. Para que haja a redução de desgaste, o pivô deve girar em relação ao balancim, mas existem certas aplicações em que o giro do pivô não é possível. Baseando-se na equação de Reynolds, o filme de óleo ao redor do pivô será avaliado e calculado com relação à distribuição de pressão. Com o conhecimento da distribuição de pressão, poderemos saber quais as forças envolvidas no subsistema. Considerando-se o atrito e os momentos gerados pelo balancim no pivô, chegamos às condições de equilíbrio do sistema. Com essas avaliações observaremos as condições que permitam a rotação do pivô em relação ao balancim / Abstract: The Valve Train System used in combustion engines have the ability to command the opening and closure of gas circulation valves control that takes part in combustion. It is formed by many sub-systems. One of these systems is the finger follower/pivot contact, where the command starts the finger follower for valve starts and uses the pivot as a support element. The knowledge of this sub-system is important to ware and noise evaluation that came ftom this contact, as well as, ftiction evaluation for the command general optimization. To reduce wear, the pivot must turn in finger follower relation, but in some applications the pivot tum is not possible. The oil film around the pivot is ca1culated in relation of its pressure distribution as Reynolds Equation. Through the knowledge of pressure distribution, the forces in the sub-system are known. Considering the ftiction and the moments generated by the balancing in the pivot, we carne to balance conditions in the system. With these evaluations we noticed the condition that allows the pivot rotation in relation to the balancing / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

<p>The objectives of this investigation were to experimentally and analytically evaluate the  performance of a valve train cam and oscillating roller follower mechanism. Of particular interest  was the effect of operating conditions on the slide-to-roll ratio (SRR) of the roller follower. In order to experimentally measure the SRR at the cam-roller contact, a valve train test rig  (VTTR) was utilized. The VTTR contained a section of a heavy-duty diesel engine valve train that  was instrumented with encoders and Hall effect sensors to measure the camshaft and roller  follower angular velocities as a function of operating parameters.  To corroborate the experimental with analytical results, a numerical model for the cam and  oscillating roller follower was developed. In this modeling approach, the roller angular velocity  was determined via a torque balance between the frictional torque of the pin-roller follower and  cam-roller follower interfaces. The pin-roller friction was obtained by developing a time-dependent hydrodynamic journal bearing model with variable speed and load. Friction maps were  developed for the cam-roller follower interface using a ball-on-disk EHD2 rig to capture the  friction behavior across a range of entraining velocities, contact pressures, and SRRs. Additional  areas of investigation included thermal effects and wear in the pin-roller contact. Overall, good agreement was obtained between the experimental and analytical roller  follower angular velocity, with the normalized RMS errors less than 7%, across all operating  conditions investigated. The analytical investigation determined that thermal effects in the pin-roller contact are insignificant for the typical operating conditions. However, it was shown that the  pin-roller friction torque is critical in causing roller follower slip, as the SRR greatly increases  once the pin-roller friction torque is greater than the cam-roller friction torque. Finally, pin-roller  local wear was demonstrated to have detrimental effects on the SRR of the roller follower once a  critical wear depth was reached. </p>

The thesis disserts upon computational modelling of valve train mechanical losses, finding the appropriate method of solving and its application on valve gear in Diesel in-line four-cylinder engine. The thesis further disserts upon proposition of appropriate adjustments leading to the reduction of mechanical losses. The calculation was performed in MBS software ADAMS.

This diploma thesis deals with valve train design of turbocharged engine used in Formula Student category race car. Based on thermodynamic model, a proper valve timing was chosen to achieve maximum power at high engine speed. A kinematic model was used to compute final cam profiles and CAD model was created.

The aim of this thesis is a comparing single valve train motion (SVT) and complete valve train motion with a flexible camshaft focused on dynamic characteristics. In this thesis is also performed kinematics analysis in the VALKIN software. Dynamic analysis is solved in the MBS software Virtual Engine. Influences to the valve train motion are described in the conclusion

Diploma thesis deals with the dynamic analysis of OHV pushrod valve train drive of the old-new conception of 6-cylinder tractor engine with 24 valves made by Zetor Tractors, a.s.. There is a requirement to create an analytical model and design valve springs for the engine. The work also points to the current analytical methods of appropriate simulation software used in automotive industry.

Die Weiterentwicklung von Verbrennungsmotoren ist geprägt von einer Steigerung der Effizienz, optimaler Betriebslaststeuerung, einer Absenkung des spezifischen Verbrauchs und der Erfüllung geltender Abgasemissionsgesetzgebung. Die Optimierung des Ladungswechsels spielt dabei eine entscheidende Rolle. Eine Möglichkeit den Ladungswechsel optimal zu beeinflussen, ist der Einsatz von variablen Ventiltrieben zur Veränderung der Ventilhubbewegung sowie zur Verstellung der Steuerzeiten. thyssenkrupp Dynamic Components entwickelt und stellt Schiebenockensysteme als diskret schaltbare Ventiltriebsysteme her, welche die verschiedenen Ventilhubanforderungen über unterschiedliche Nockenprofile auf dem Schiebeelement nebeneinander abbilden können. Im Entwicklungs- und Auslegungsprozesses kommt eine Simulation des Bewegungs-, Beschleunigungs- und Abbremsverhaltens sowie der Kraftverläufe beim Verstellvorgang mittels einer Mehrkörpersimulation (MKS) in der Software alaska/ModellerStudio zum Einsatz. In diesem Beitrag wird das MKS-Modell des Schiebelements sowie der Abgleich des Modells mit Versuchen vorgestellt. Es folgt eine Darstellung von Optimierungsmöglichkeiten bereits in der Simulationsumgebung, bei denen die Kontaktnormalkräfte und Beschleunigungen in mehreren Iterationsschleifen auf den gewünschten Anwendungsfall angepasst werden können. Unter Berücksichtigung der Fertigungs- und Lagertoleranzen sowie des Verschleißverhaltens kann das System mit diesem Simulationstool bereits virtuell abgeprüft werden. / The advancement of internal combustion engines is characterized by an increase in efficiency, optimum operating load control, a reduction in specific consumption and compliance with applicable exhaust emission legislation. Optimization of the charge change plays a decisive role in this. One way of optimally influencing the charge change is to use variable valve trains to change the valve lift and adjust the timing. thyssenkrupp Dynamic Components develops and manufactures sliding cam systems as discretely switchable valve train systems that can feature the various valve lift requirements side by side via different cam profiles on the sliding element. A simulation of the motion, acceleration and deceleration behavior as well as the force curves during the sliding process by means of a multi-body simulation (MBS) in the alaska/ModellerStudio is applied in the development and design process. This presentation shows the MBS model of the sliding cam and the comparison of the model with test results. Various optimization options in the simulation environment present, how the contact normal forces and accelerations can be adapted in several iteration loops to the desired application. Taking into account the manufacturing and bearing tolerances as well as the wear behavior, this simulation tool allows to virtually check the sliding cam system.