Numerical and Simulation Approach for Design of Variable Valve Actuation Mechanism on Single-Cylinder Diesel Engine

Abstract

Diesel engine requires continuous improvements not only in performance front but emissions front as well to meet upcoming stringent emission regulations and fuel economy requirements. Challenges to meet future emission standards not only require technological upgradation for combustion optimization, but also requires better engine thermal management with emission and performance. Variable valve actuation (VVA) solutions are effective for combustion quality and temperature management with various timing and lift options. The upcoming emission norms for LCV application engine are very challenging and require significant management of combustion strategies including in cylinder flow control and distribution. The variable valve actuation mechanism is designed considering the assembly constraints to have flexibility of higher intake valve lift and duration compared to existing configuration, suitable to the engine performance requirement. The new design of cam profile is analyzed for kinematic and dynamic performance for variable valve actuation mechanism and compared with existing cam profile performance. The dynamic analysis of whole VVA mechanism is carried out to evaluate lift, velocities and accelerations profile. The purpose of this work is to develop a methodology for design, analysis and evaluation of variable valve actuation systems used for the control of intake valve movement in single-cylinder LCV application diesel engine. The strategy begins with detailed study of existing valvetrain system, assembly layout and design of proposed VVA system using CAD software, and consequently, numerical simulation of components and assembly is carried out within prescribed boundary condition. Engine parameters like fuel efficiency, volumetric efficiency, power output and exhaust emissions depend upon the quantity of air going in the combustion chamber, and this is controlled by opening and closing of inlet and exhaust valves. Due to strict regulations on emission control, controlling the flow through inlet and exhaust valves plays an important role. This paper deals with the design of a variable valve actuation mechanism employing solenoid valves, on a single-cylinder diesel engine. Multibody dynamic analysis of this new mechanism is carried out in MSC ADAMS, the results of which are compared with the conventional valvetrain mechanism. A finite-element structural analysis of the individual components of the mechanism is done in ANSYS 16.0 to verify the integrity of the components under the actuating forces.