Analytical and Experimental Assessment of Some Novel Variable-Valve-Actuation Mechanisms

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Burak Gecim ◽  
Madhusudan Raghavan
Keyword(s):  
Test Results ◽  
Experimental Assessment ◽  
Variable Valve Actuation ◽  
Mechanical Variable ◽  
Experimental Works ◽  
Design Solutions ◽  
Variable Valve ◽  
Actuation Systems ◽  
Deactivation Mechanism ◽  
Valve Actuation

We describe our analytical and experimental works on three novel variable valve actuation systems. These include a mechanical variable-lift and duration concept, a hydraulic-lost-motion variable-lift system, and a valve-deactivation mechanism with unique features. These devices differ in their complexity and versatility but offer a spectrum of design solutions applicable to a range of products. The strengths and weaknesses of these different approaches are discussed and analyzed, and some test results are presented.

New mechanical variable valve actuation systems for motorcycle engines

2014 ◽  
Vol 229 (4) ◽  
pp. 716-734 ◽  
Author(s):  
Carmelina Abagnale ◽  
Mariano Migliaccio ◽  
Ottavio Pennacchia
Keyword(s):  
High Performance ◽  
Numerical Procedure ◽  
Valve Lift ◽  
Beneficial Effects ◽  
Variable Valve Actuation ◽  
Mechanical Variable ◽  
Set Up ◽  
Variable Valve ◽  
Actuation Systems ◽  
Valve Actuation

This paper summarizes the results of the design of new mechanical variable valve actuation systems, developed for high-performance motorcycle engines, at University of Napoli Federico II, Department of Industrial Engineering – Section Mechanics and Energy. After a synthetic recapitulation of the main variable valve-actuation methods and of the main beneficial effects on performance, emissions, and consumptions of the modern automotive engines on which they are currently employed, the paper presents the results of our mechanical variable valve actuation systems, born to be applied on a MotoMorini engine, as required by the company. The paper starts with the description of a first study concerning a very simple system, used just to set up a model to be used for further and more complex activities. The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from some input data (as described later). The model has been validated against the conventional timing system using kinematic simulations. The work has evolved through three main steps leading to three types of variable valve actuation systems, all mechanical systems (as defined in literature and described later). Results of the numerical procedure verify the validity of the variable valve actuation systems, and particularly, the last one shows a complete performance in terms of lift, duration, and timing variation of valve-lift law. This paper reports results reachable with these simple systems that give good perspectives of use for a new two-wheel vehicle engine.

Variable Valve Actuation for Advanced Powertrains

2008 ◽  
Author(s):  
Burak Gecim ◽  
Madhusudan Raghavan
Keyword(s):  
Valve Lift ◽  
Test Results ◽  
Variable Valve Actuation ◽  
Lift Mechanism ◽  
Comprehensive Survey ◽  
Variable Valve Lift ◽  
Direct Acting ◽  
Variable Valve ◽  
Considerable Detail ◽  
Valve Actuation

We review variable valve actuation (VVA) concepts and also present the results of our work in the creative synthesis of these devices. We begin with a comprehensive survey of existing VVA devices. We then describe our work on four VVA concepts which we have explored in considerable detail. These include hydraulic lost-motion variable-lift systems, in both the direct acting and the roller-finger-follower configurations, several valve deactivation mechanisms with unique features, a variable valve-lift mechanism, and a variable-lift and duration concept. These devices differ in their complexity and versatility but offer a spectrum of design solutions applicable to a range of products. The strengths and weaknesses of these different approaches are discussed and analyzed, and some test results are presented.

Design of a New Mechanical Variable Valve Actuation System for Motorcycle Engines

2012 ◽  
Author(s):  
Carmelina Abagnale ◽  
Mariano Migliaccio ◽  
Ottavio Pennacchia
Keyword(s):  
High Performance ◽  
Numerical Procedure ◽  
Valve Lift ◽  
Variable Valve Actuation ◽  
Actuation System ◽  
Mechanical Variable ◽  
System 2 ◽  
Variable Valve ◽  
System 1 ◽  
Valve Actuation

This paper deals with design and manufacturing of a mechanical variable valve actuation (VVA) system, developed as part of a MUR financed research project concerning the realization of a high performance motorcycle engine, through a partnership of Moto Morini (Bologna), Dell’Orto (Milano), Istituto Motori - CNR (Napoli) and DiME (Department of Mechanical Engineering and Energetics) – University of Napoli Federico II. After a synthetic description of the main variable valve actuation methods currently employed, the paper presents the results of our mechanical VVA system, consisting of three main elements: cam, main rocker arm with fixed fulcrum and secondary rocker arm with mobile fulcrum. This VVA system (system 1) enables valve lift variation by a simple translation of one of the three elements (the intermediate one). The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from the following input data: rocker arm geometry, relative positions and inertial data of elements, spring stiffness and preloading, camshaft speed and valve lift law. The model has been validated against the conventional timing system using kinematic simulations. Results of the numerical procedure verify the validity of the VVA system, capable of a valve lift variation, with a limited acceleration. Starting from the numerical results, we have developed a new mechanical variable valve actuation system (system 2): it consists of the same three elements used previously, but they are connected in a different way. The newer system enables more general lift profile distributions with a similar geometric complexity. The activity has been extended to research for a new solution (always a mechanical system), capable to allow inlet valves complete closing and timing and duration variation (system 3). This paper reports results reachable with the simplest system 1, that gives better perspectives of use for a new two-wheel vehicle engine.

A new mechanical variable valve actuation system for motorcycle engines

2009 ◽  
Author(s):  
C. Abagnale ◽  
S. Caruso ◽  
A. Iorio ◽  
M. Migliaccio ◽  
O. Pennacchia
Keyword(s):  
Variable Valve Actuation ◽  
Actuation System ◽  
Mechanical Variable ◽  
Variable Valve ◽  
Valve Actuation
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