Reference signal generator for active power filters using MGP-FIR filter designed by evolutionary programming

This paper describes a high-performance reference signal generator for active power filters extracting the fundamental signal component from distorted current signals. In order to achieve high-quality output as well as computationally effective algorithm, the generator employs an adaptive and predictive MGP-FIR (Multiplicative General Parameter) bandpass filter designed by evolutionary programming. Detailed procedures of MGP-FIR filtering and evolutionary optimization are first discussed; theoretical conclusions are verified by illustrative simulation results.reviewe

Time-Dependent Performance Comparison of Stochastic Optimization Algorithms

This paper proposes a statistical methodology for comparing the performance of stochastic optimization algorithms that iteratively generate candidate optima. The fundamental data structure of the results of these algorithms is a time series. Algorithmic differences may be assessed through a procedure of statistical sampling and multiple hypothesis testing of time series data. Shilane et al. propose a general framework for performance comparison of stochastic optimization algorithms that result in a single candidate optimum. This project seeks to extend this framework to assess performance in time series data structures. The proposed methodology analyzes empirical data to determine the generation intervals in which algorithmic performance differences exist and may be used to guide the selection and design of optimization procedures for the task at hand. Such comparisons may be drawn for general performance metrics of any iterative stochastic optimization algorithm under any (typically unknown) data generating distribution. Additionally, this paper proposes a data reduction procedure to estimate performance differences in a more computationally feasible manner. In doing so, we provide a statistical framework to assess the performance of stochastic optimization algorithms and to design improved procedures for the task at hand

A General Framework for Statistical Performance Comparison of Evolutionary Computation Algorithms

This paper proposes a statistical methodology for comparing the performance of evolutionary computation algorithms. A two-fold sampling scheme for collecting performance data is introduced, and these data are analyzed using bootstrap-based multiple hypothesis testing procedures. The proposed method is sufficiently flexible to allow the researcher to choose how performance is measured, does not rely upon distributional assumptions, and can be extended to analyze many other randomized numeric optimization routines. As a result, this approach offers a convenient, flexible, and reliable technique for comparing algorithms in a wide variety of applications

Performance and emissions of a non-road diesel engine driven with a blend of renewable naphtha and diesel fuel oil

Diesel engines are still the predominant power source in heavy-duty vehicle, non-road, marine and power generation applications globally. They are reliable stand-alone machines with a high brake thermal efficiency (BTE) across a wide output range. Most diesels burn fuel derived from crude oil. However, the share of renewable fuels is growing in re-sponse to the need to reduce greenhouse gas emissions (GHG). This study evaluated the suitability of a blend of renew-able naphtha (20 vol.-%) and low-sulphur light fuel oil (LFO, 80 vol.-%) for a high-speed, non-road engine. Neat LFO served as the baseline fuel. Wood residue-based hydrotreated vegetable oil (HVO) was the study’s third test fuel. With HVO, the engine BTE was a shade higher than with the blend or LFO. HVO also reduced NOx slightly and emitted the lowest HC and the lowest PN within the entire size range of 6 to 560 nm. The blend and LFO showed similar NOx emis-sions. The blend’s HC emissions were higher than LFO’s. The blend produced the lowest particle number (PN) of above particles 23 nm: LFO produced the highest. Potent GHG compounds CH4 and N2O were negligible for all three fuels.fi=vertaisarvioimaton|en=nonPeerReviewed

Convertability and Oil Resistance of Paperboard with Hydroxypropyl-Cellulose-Based Dispersion Barrier Coatings

The convertability and barrier properties of paperboard coated with hydroxypropyl-cellulose (HPC) based dispersions were studied via tray pressing trials, oil resistance measurements and microscopic analyses. To improve the oil resistance of the HPC-based coatings and to maximize their convertability, talc, gelatin and latex were used as additives in coating formulations. The oil resistance of the coatings improved to some extent with these additives, but scanning electron micrographs revealed the existence of pinholes particularly in coatings with a high HPC content. The coated paperboard samples were pressed into rectangular trays and the convertability of the paperboards was evaluated with a microscope. Thereafter, the oil resistance of the trays was determined in order to clarify how the tray pressing process affected the oil resistance. Pure HPC coating did not provide appreciable oil resistance to the paperboard, but the composite coatings resisted oil up to 11 minutes at the tray corners, which were considered the most demanding regions in the tray. The pure HPC coating was sticky and tended to stick to the converting tools in the press forming. Adding talc to the coating dispersion reduced this problem. By applying a thin pre-coating layer, it was possible to raise the blank holding force in the pressing process from 1.16 kN to 1.55 kN without causing rupture in the tray corner areas or compromising the quality of the creases. With commercial polyethylene-terephthalate-coated reference paperboard, the use of such a high force resulted in long rupture and opened creases, which confirms the excellent applicability of the developed dispersion-coating recipes for the tray-pressing process. These observations suggest that convertibility is not necessarily a major problem with bio-based dispersion barrier coatings and that more attention should be paid to their barrier properties and particularly to the prevention of pinholes being formed during the coating process

Effects of alternative marine diesel fuels on the exhaust particle size distributions of an off-road diesel engine

The main objective of this study was to find out how alternative fuels affect the exhaust gas particle size distribution. The fuels are later intended for marine applications. Along with low-sulfur marine light fuel oil (LFO), a high-speed off-road diesel engine was fueled by circulation-origin marine gas oil (MGO), rapeseed methyl ester (RME), crude tall oil derived renewable diesel (HVO), the 20/80 vol.-% blend of renewable naphtha and marine LFO, and kerosene. Particle size distributions were measured by means of an engine exhaust particle sizer (EEPS), but soot, gaseous emissions and the basic engine performance were also determined. During the measurements, the 4-cylinder, turbocharged, intercooled engine was run according to the non-road steady cycle complemented by an additional load point. The engine control parameters were kept constant, and any parameter optimization was not made with the studied fuels. Relative to baseline LFO, both naphtha-LFO blend and RME reduced particle numbers above the size range of 50 nm. Circulation-origin MGO and kerosene generated a high total particle number (TPN), most likely due to their higher sulfur contents. MGO and RME were beneficial in terms of carbon monoxide (CO) and hydrocarbon (HC) emissions while nitrogen oxide (NOx) emissions were the highest with RME. The differences in smoke emission were negligible.fi=vertaisarvioitu|en=peerReviewed

Selective Catalytic Reduction on Filter Performance Testing on Non-road Diesel Engine

High-efficiency lean-burn compression ignition engines are expected to continue to play an important role as a power source for non-road mobile machinery. The challenge for these engines is that they suffer both high levels of nitrogen oxide (NOx) and particulate matter (PM) emissions, and the simultaneous reduction of these particular emissions is difficult due to the trade-off relationship between NOx and PM. Consequently, achieving the most stringent emission limits requires efficient exhaust aftertreatment. Traditionally, NOx and PM have been controlled by separate aftertreatment devices. However, such sequential system configurations have several disadvantages, such as a large volume of the aftertreatment system. The compact design of a selective catalytic reduction (SCR)-coated diesel particulate filters (DPF), referred to as selective catalytic reduction on filter (FSCR), allows the reduction in aftertreatment system volume and mass. Another advantage is that the SCR can be placed closer to the engine to improve SCR temperature behavior. The major challenge of the FSCR technology is the interaction between the SCR and DPF functions. The present study examines the operation of a state-of-the-art combined particulate filter and SCR catalyst device as a part of an exhaust aftertreatment system on a high-speed non-road diesel engine. Unlike previous studies, the goal was a complete ammonia (NH3) slip-free operation. The main objective was to investigate how the SCR properties—NOx conversion and NH3 slip—change when the filter fills up with soot. In this context, tests with clean FSCR and with soot-loaded FSCR were conducted at varying urea dosing. The soot-loaded FSCR, compared with a clean one, showed a slightly (4-6%) lower NOx reduction and higher (1-4 ppm) NH3 slip under identical operating conditions. The results also indicated a decrease in NH3 storage capacity upon soot loading. Finally, a supplementary flow-through SCR catalyst was added downstream of the FSCR, and tests with FSCR only versus FSCR + SCR were performed. Adding the second SCR allowed for higher urea dosing without NH3 slip and, consequently, higher (+23%) NOx conversions.© 2021 The Authors. Published by SAE International. This Open Access article is published under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits distribution, and reproduction in any medium, provided that the original author(s) and the source are credited.fi=vertaisarvioitu|en=peerReviewed

B20 Fuel Compatibility with Steels in Case of Fuel Contamination

This study evaluated the compatibility with steels for three B20 fuel samples blended from fossil diesel and used cooking oil methyl ester. One sample was untreated and its concentration of copper was analyzed as <1 ppm. Another sample was doped by adding Cu at a concentration of ≤2 ppm and the third sample by adding Cu at a concentration of ≤4 ppm. Steel samples (carbon steel, stainless steel and a special alloy) were then put into the fuel blends and stored at 50 °C for 692 h. After storing, the metal concentrations of the fuel blends were again analyzed, and signs of corrosion were evaluated visually. The aim of this study was to find out if the fuel already contaminated by copper will affect the corrosion of the chosen steel qualities. Additionally, fuel properties were measured for all three blend samples before the immersion of steels. Visual evaluation of the steels indicated that signs of corrosion were seen in all studied samples, but Cu doping did not increase the signs of corrosion notably. The results also showed that the copper content from 1 to 2 and 4 ppm reduced the oxidation stability and increased the acid number of the fuel samples.© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Effects of Crude Tall Oil Based Renewable Diesel on the Performance and Emissions of a Non-Road Diesel Engine

Environmental concerns and government policies aiming to increase biofuel shares have led to the search for alternative fuels from a variety of renewable raw materials. The development of hydrotreated vegetable oil (HVO) type fuels has been strong in the Nordic countries, partly due to the early use of tall oil from the forest industry as feedstock. An innovative production process to convert crude tall oil (CTO) - a residue of pulp production - into high-quality renewable diesel fuel was developed by a Finnish forestry company UPM. Paraffinic, high cetane and low aromatic CTO renewable diesel allows efficient and clean combustion, resulting in reductions of local air pollution in addition to not releasing any new CO2 into the atmosphere during their combustion. This research investigated the influence of CTO renewable diesel on the performance and exhaust emissions of a non-road diesel engine. The examined fuels were neat CTO renewable diesel (BVN) and a blend of BVN and fossil diesel fuel oil (DFO) (50/50% v/v). Neat DFO served as the reference fuel. During a thorough test bench campaign, the engine was driven with the loads of the ISO 8178-4 C1 test cycle. The test engine had no exhaust after-treatment system, and no engine modifications or parameter optimizations were made during the tests. CTO renewable diesel proved to be beneficial in terms of CO, HC and particle number (PN) emissions. With neat BVN, a reduction of 9 % for CO, 10 % for HC, and 10% for PN compared with DFO were observed. The beneficial trends were most evident at low loads. Renewable fuel also slightly reduced brake specific NOx emissions. CTO renewable diesel proved to be a high-quality, sustainable alternative to fossil diesel and fully compatible with existing non-road diesel engines.©2021 SAE International.fi=vertaisarvioitu|en=peerReviewed