INVESTIGATIONS ON WEAR AND FRICTION IN THE SI ENGINE VALVETRAIN

The engine valvetrain system operating under conditions of insufficient oil lubrication, caused by incorrect installation of the gasket between the block and the head, was tested. The aim of the analysis was to determine the wear intensity and resistance to motion in camshaft bearings. A model was developed that includes a camshaft, bearings, tappet-valve-spring subassemblies and a part of the lubrication system. It was used to determine the bearing loads and the amount of oil supplied. The volumetric wear of the camshaft journals and bearing covers was measured. For the estimated engine run, the wear rate and resistance to motion were compared for the cases of the engine with correct and incorrect lubrication.

Rancang Bangun Alat Uji Tekanan Pegas Katup Toyota Kijang 7K Berbasis Microcontroler

This research discusses the design of a toyota kijang 7K valve spring pressure test tool with microcontroller based, This type of research is a level 3 of development research with several stages, namely: potential and problems, product design, system validation, design revision, product manufacturing, testing product trials, product revisions, usage trials, product revisions. Based on the research conducted, several things can be concluded, namely. First, the use of the level 3 of development research method can be applied in research on the design of a Toyota Kijang 7K valve spring pressure test instrument with microcontroler based. Second, when testing the valve spring compression, it is carried out 3 times, so that the percentage of tools designed to produce an error is 3,7% and the accuracy percentage of the tool reaches 96,3%. Penelitian ini membahas mengenai rancang bangun alat uji tekanan pegas katup toyota kijang 7K berbasis microcontroler . Jenis penelitian ini adalah penelitian pengembangan level 3 dengan beberapa tahap, yakni: potensi dan masalah, desain produk, validasi sistem, revisi desain, pembuatan produk, uji coba produk, revisi produk, uji coba pemakaian, revisi produk. Berdasarkan penelitian yang dilakukan dapat disimpulkan beberapa hal, yaitu. Pertama penggunaan metode penelitian pengembangan level 3 dapat diterapkan dalam penelitian rancang bangun alat uji tekanan pegas katup Toyota kijang 7K berbasis microcontroler. Kedua pada saat melakukan pengujian terhadap penekanan pegas katup dilakukan sebanyak 3 kali, sehingga didapatkanlah persentase alat yang dirancang dengan menghasilkan error senilai 3,7% dan persentase akurasi alat mencapai 96,3%.

Conceptual Design and Finite Element Fatigue Life Analysis of a Poppet Valve Spring Compressor

In the overhauling of the internal combustion engine, a lot of tools are used and among them is the poppet valve spring compressor. In Ghana, auto mechanics at the “way-side” garages make use of improvised tools, such as pipes, pliers, and push rods, for compressing valve springs. However, there are some challenges associated with the usage of these tools which include misplacement of cotters, injuries, and sometimes valve bends. In this work, a review of some of the existing designs of the improvised tools was considered. Also, a survey was conducted to seek the opinion of users (auto technicians and/or mechanics) of the tools. A design was made for spring compression by incorporating a magnet with a pull force of 679.78 N to take care of the removal of cotters during valve assembly dismantling. In this research, an efficient and user-friendly poppet valve spring compression tool with a total mass of 0.88 kg was designed. Finite element analysis (FEA) was performed on the upper and lower parts of the tool to examine its response due to the loads that act on it during operation. It was discovered from the analysis that the upper frame of the valve spring compressor experienced the highest von Mises stress of 59.77 MPa at the neck region, whilst the corresponding fatigue analysis showed a maximum fatigue life of 8.355 × 109 cycles.

SIMULASI PEREDAMAN GETARAN PADA PEGAS KATUP (VALVE SPRING) SISTEM HIDROLIK DENGAN METODE PID MEMANFAATKAN SIMULINK MATLAB

A simulation of damping vibration on valve spring hydraulic system has been done. This research is a study of the simulation that aims to control excess vibration on valve spring hydraulic system as a result of excitation force that is affected by the changes of pressure periodically, to produce a stable system. The simulation performed by using Matlab simulink with applying a PID method (P, PD, PI and PID) and noticed to variations of proportional constant (Kp), integral constant (Ki) and the derivative constant (Kd). The simulation results obtained show that by combining these three constants Ki, Kp and Kd can dampen the vibration better. For the total excitation force, using the value of Kp = 106, Ki = 7 x 106 and Kd = 6 x 104 can provide damping vibration system response on valve spring with a rise time of 1.2119 s, settling time of 1.2792 s, stable at setpoint 1, error steady state 0% and a small maximum overshoot of 0.3309. This is the result of a stable system response and best compared to the other combinations of the constant values. Keywords : vibration, damper, valve spring, hydraulic system, PID method.

Edge States in Nonlinear Model of Valve Spring

We address the dynamics of helical compression valve springs of an internal combustion engine. To this end, the spring is mathematically modeled as a finite non-homogenous one-dimensional mass-spring-damper discrete chain. Regarding the boundary conditions, the upper end of the chain is forced with periodic displacement, which mimics the actual camshaft profile, while the other end is fixed. In order to model the interaction between the valve and valve seat, the displacement of the upper mass is constrained to be nonnegative by adding an obstacle such that when it approaches the obstacle, it experiences an impact that satisfies the Newton impact law with restitution coefficient less than unity. Another source of damping in this model arising from the internal damping of the spring material. The nonlinearity of the model originates from the periodic impact interactions. This interplay between nonlinearity and discreteness supports time-periodic and spatially localized solutions characterized by a strong localization at the edge of the chain (i.e. edge states) such that the periodicity of the impact allows derivation of exact analytical solutions for the forced-damped edge state. Then, the governing equations are solved numerically in order to illustrate the exact solution. The results are compared to experimental findings from analysis of actual automotive valve spring.