Modeling of Variable Valve Timing on High Performance Engine using Power-Oriented Graphs Method

Abstract

Engine efficiency is one of the key aspects to reduce CO2 emissions. In order to improve the emission maintaining high performance capabilities several devices are introduced in the system; variable valve timing technology allows more flexibility for modern engines to meet peak performance, fuel economy and low emissions targets while providing good driveability. This paper describes the Lamborghini continuously-variable cam phaser model using a graphical technique, called Power Oriented Graphs (POG), that uses an energetic approach for representing the physical systems. The generally accepted approach is to calibrate an engine on a dynamometer and to adjust the operation of the engine to meet performance targets. With the current build and test approach, these adjustments may not be made until well into the development program, and this calibration is a costly and time consuming step in the engine development process: the main purpose of this works is allowing a faster model's calibration time. Furthermore the usefulness to model the system consists of analyzing in simulation many more system configurations than those available for real experiments so it's important using a simple methodology that is able to analyze the whole system's dynamic in order to reach the performance expectations. The results obtained were validated demonstrating the effectiveness of the POG technique.

Dynamic behaviour modelling of an internal combustion engine water pump transmission belt drive

“…T is the belt preload, k is the stiffness of the two belt sides, r 1 and r 2 the radius of the driving and the driven pulley. The motion equations have been written imposing the torque equilibrium conditions on the pulleys (Corvino et al, 2011). Referring to the system in Figure 3, we can write:…”

“…Modal analysis has been performed to estimate the natural frequencies and the related modal shapes of the time system analysed Guida, 2018b, 2018c). The belt system has been forced via an impact hammer, while a laser Doppler vibrometer (Corvino et al, 2011), has recorded the out-of-plain transverse vibrations. In the table below are reported the first natural frequencies and the vibration modes, given in terms of nodal lines (NL), experimentally measured.…”

Simulation of Dynamic Stresses on High Performance Engine Valve Spring System Considering Coil Clashing Effect

“…The predictive modeling of the valve train dynamic [1] is essential for durability analysis at the highest engine speed conditions [2]. The method to calculate the complex dynamic of the valve-spring systems allows a correct representation of flexible and complex contacts under full consideration of the system dynamics.…”

Fuel economy analysis of part-load variable camshaft timing strategies in two modern small-capacity spark ignition engines

“…In the last three decades, advanced technologies such as direct injection, turbo-charging and Variable Camshaft Timing (VCT), have contributed significantly to the evolution of engine design. Combinations of these technologies, along with engine down-sizing, have simultaneously delivered positive effects on fuel consumption and emissions [2,3], as well as on driving pleasure [4].…”