This article presents a novel methodology to design swash plate type axial piston machines based on computationally based approach. The methodology focuses on the design of the main lubricating interfaces present in a swash plate type unit: the cylinder block/valve plate, the piston/cylinder, and the slipper/swash plate interface. These interfaces determine the behavior of the machine in term of energy efficiency and durability. The proposed method couples for the first time the numerical models developed at the authors’ research center for each separated tribological interface in a single optimization framework. The paper details the optimization procedure, the geometry, and material considered for each part. A physical prototype was also built and tested from the optimal results found from the numerical model. Tests were performed at the authors’ lab, confirming the validity of the proposed method.
Ferrari, A., Novara, C., Paolucci, E., Vento, O., Violante, M., and Zhang, T.
Applied Energy, 2018, 232, C, 358.
Fuel injection system, Diesel engine, Injected mass control, and Rapid prototyping hardware
A closed-loop strategy that is capable of controlling the fuel injected mass in the combustion chamber of a Common Rail diesel engine has been set up. The pressure time histories measured along the rail-to-injector pipe have been used to evaluate the instantaneous mass flow-rate entering the injector. This flow-rate has then been integrated between two time instants, and the thus calculated fuel mass has resulted to correlate well with the injected mass.
András Poppe, Gábor Farkas, Lajos Gaál, Gusztáv Hantos, János Hegedüs, and Márta Rencz
Energies, 2019, 12, 10, 1.
light emitting diodes, power LEDs, multi-domain modelling, and LED luminaire design
This paper presents our approaches to chip level multi-domain LED (light emitting diode) modelling, targeting luminaire design in the Industry 4.0 era, to support virtual prototyping of LED luminaires through luminaire level multi-domain simulations. The primary goal of such virtual prototypes is to predict the light output characteristics of LED luminaires under different operating conditions. The key component in such digital twins of a luminaire is an appropriate multi-domain model for packaged LED devices that captures the electrical, thermal, and light output characteristics and their mutual dependence simultaneously and consistently. We developed two such models with this goal in mind that are presented in detail in this paper. The first model is a semi analytical, quasi black-box model that can be implemented on the basis of the built-in diode models of spice-like circuit simulators and a few added controlled sources. Our second presented model is derived from the physics of the operation of today’s power LEDs realized with multiple quantum well heterojunction structures. Both models have been implemented in the form of visual basic macros as well as circuit models suitable for usual spice circuit simulators. The primary test bench for the two circuit models was an LTspice simulation environment. Then, to support the design of different demonstrator luminaires of the Delphi4LED project, a spreadsheet application was developed, which ensured seamless integration of the two models with additional models representing the LED chips’ thermal environment in a luminaire. The usability of our proposed models is demonstrated by real design case studies during which simulated light output characteristics (such as hot lumens) were confirmed by luminaire level physical tests.