Nonlinear Transient Response of a High Speed Driven Valve System and Stresses in Valve Springs for Internal Combustion Engines

1989 ◽  
Vol 111 (3) ◽  
pp. 264-271 ◽  
Author(s):  
K. Nagaya
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Three Dimensional ◽  
Beam Theory ◽  
Internal Combustion ◽  
Valve Train ◽  
Combination Method ◽  
Combustion Engines ◽  
Valve System ◽  
Cam Profile

This paper presents a method for solving the dynamic response problems of a driven valve system and the stress problem of valve springs for internal combustion engines. In this system there is hysteresis behavior in the spring constants during the rotation of the cam shaft. To treat this nonlinearity, the rigidity of each section is assumed to be one of a partly linear spring. For the valve trains, the cam profile is complex in general. To treat a general cam profile, this paper applies a combination method of the Fourier expansion, the Laplace transform and the analytical connection methods, and gives a response of valve trains. This paper also presents a theoretical result for the stresses in the valve spring due to the motion of the valve train based on the three dimensional curved beam theory.

Mathematical modeling and simulation of high-speed cam mechanisms to minimize residual vibrations

2014 ◽  
Vol 228 (13) ◽  
pp. 2402-2415 ◽  
Author(s):  
Halit Kaplan
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Dimensionless Analysis ◽  
Multipliers Method ◽  
Cam Follower ◽  
Cam Profile

Mathematical modeling, simulation, and optimum design of equivalent one degree-of-freedom high-speed cam mechanisms used for internal combustion engines are investigated in this study. The dynamic equation governing the dynamic behavior of a typical high-speed cam–follower system of an internal combustion engine has been simplified using dimensionless analysis method. The resulting model is then used to find the optimum cam shape to reduce the residual vibrations in the follower part of the system. The Lagrange multipliers method is utilized to minimize the sum of squared error (deviation from the cam profile) over one period under continuity and smoothness constraints.

A Versatile Acceleration-Based Cam Profile for Single-Dwell Applications Requiring Cam-Follower Clearance During Dwell

2011 ◽  
Author(s):  
Forrest W. Flocker
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Velocity Function ◽  
Gas Leakage ◽  
Poppet Valve ◽  
Equation Solving ◽  
Cam Follower ◽  
Cam Profile

Presented in this paper is a cam motion program suitable for single-dwell cam-follower systems with built-in clearance between the cam and follower during the dwell portion of the cycle. This makes the motion program particularly well-suited to applications such as valve trains in internal combustion engines in which cam-follower clearance is necessary to ensure proper seating of a poppet valve, preventing gas leakage across the seal. The motion program for the cam follower is derived from the follower acceleration function so that designers can control the ratio of the magnitudes of positive and negative accelerations. This provides cam designers more control over the cam-follower interface force and therefore more control over factors such as cam wear and the potentially destructive phenomenon known as “follower jump.” Included in the motion program is asymmetric rise and fall that allows different times for these events. The follower acceleration is designed to be smooth enough to provide continuous jerk throughout the actuation phase, thereby tending to reduce undesirable residual vibrations. The motion program used to close and open the clearance gap is derived from a velocity function, allowing more control of follower inertia during the important clearance closing event. The motion program is presented in a form appropriate for implementation in standard engineering equation-solving software, giving the cam designer easy control over important parameters in high-speed cam-follower systems.

Improving the tribological behavior of internal combustion engines via the addition of nanoparticles to engine oils

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Mohamed Kamal Ahmed Ali ◽  
Hou Xianjun
Keyword(s):  
Internal Combustion Engines ◽  
Tribological Behavior ◽  
Internal Combustion ◽  
Valve Train ◽  
Combustion Engines ◽  
Power Losses ◽  
Oil Consumption ◽  
Engine Oils ◽  
Engine Efficiency ◽  
Sliding Surfaces

AbstractThe friction between two sliding surfaces is probably one of the oldest problems in mechanics. Frictional losses in any I.C. engine vary between 17% and 19% of the total indicated horse power. The performance of internal combustion engines in terms of frictional power loss, fuel consumption, oil consumption, and harmful exhaust emissions is closely related to the friction force and wear between moving parts of the engine such as piston assembly, valve train, and bearings. To solve this problem, most modern research in the area of Nanotribology (Nanolubricants) aims to improve surface properties, reduce frictional power losses, increase engine efficiency, and reduce consumed fuel and cost of maintenance. Nanolubricants contain different nanoparticles such as Cu, CuO, TiO

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