Variable Valve Actuation Systems for the Optimization of Engine Torque

1991 ◽  
Author(s):  
Wolfgang Demmelbauer-Ebner ◽  
Alois Dachs ◽  
Hans Peter Lenz
Keyword(s):  
Engine Torque ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Actuation Systems ◽  
Valve Actuation

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.

A Study of Engine Torque Control by Variable Valve Actuation

2005 ◽  
Author(s):  
Yutaro Minami ◽  
Hiroshi Iwamo ◽  
Hiraku Ooba ◽  
Naonori Onoda
Keyword(s):  
Torque Control ◽  
Engine Torque ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Valve Actuation

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.

A New Valve Lift Control Technique in Electrohydraulic Variable Valve Actuation Systems

2010 ◽  
Author(s):  
Mohammad Pournazeri ◽  
Amir Khajepour ◽  
Amir Fazeli
Keyword(s):  
Control Valve ◽  
Operating Conditions ◽  
Valve Lift ◽  
Control Technique ◽  
Variable Valve Actuation ◽  
Actuation System ◽  
Lift Control ◽  
Variable Valve ◽  
Actuation Systems ◽  
Valve Actuation

Besides valve timings and opening duration control, several benefits could be achieved in engine operation if the valve actuation system could control the maximum valve displacement during a particular engine condition. Typically, in most electro-hydraulic variable valve actuation systems (VVA), the maximum valve lift along with valve opening/closing events are adjusted simultaneously by precise control of the spool travel in servo-valves. However, at high engine speeds, concurrent control of timings and peak valve lift becomes difficult and sometimes even impossible due to servo-valve response time limitations. In this paper, a new lift control technique is proposed using a control-valve located in the hydraulic supply line. Using this technique, it is possible to precisely control the valve lift even at high engine speeds. With this mechanism, the control-valve flow area could be adjusted using a low-speed actuator such as an electric motor. In contrast to conventional approaches, where maximum lift is repeatedly controlled within each cycle, valve lift in this technique can be adjusted after few engine cycles, thereby reducing control signal fluctuations and also eliminating the need for ultra-high-speed actuators. The proposed hydraulic VVA system is mathematically modeled, and a non-linear sliding mode controller is designed based on the derived equations. Finally, the performance of the proposed lift control technique is verified under different operating conditions.

Sign in / Sign up

Export Citation Format

Share Document