The article presents the results of calculations and analysis of the eM ratio of the propulsion energy consumption per the nautical mile and the eMt ratio of the propulsion energy demand for the transport of 1-ton cargo per the nautical mile for bulk carriers. The relationship between eM and eMt indicators with the EIV (Estimated Index Value) ratio is shown. The output data for the determination of eM and eMt indicators was taken from the quoted MAN publication, reading (reproducing) the values of power, velocity v and DWT tonnage from the charts included in this publication. Calculations and analyses were made for velocity v between 11-15 knots and for DWT from 5-400 kt (kilo tonnes). The graphs of eM and eMt ratios in the function of speed v and load capacity DWT are presented. Using the stepwise method of least squares, models of statistical dependence of indicators on velocity v and load capacity of bulk carriers were developed. They were based on generalized polynomials with integer exponents. Derivatives deM / dv and deMt / dv and derivatives deM / dDWT and deMt / dDWT were determined. The main observations resulting from the conducted analyses are observed with the increase of DWT (within the range of 80-100 kt) a significant decrease in the value of the eM index. For DWT values> 100 kt, the decrease in eMt is slow − eMt asymptotically tends to a constant value. The results of the analyses carried out can be used at the stage of designing the transport capacity (tonnage) and nominal speed of the ship as well as selection of ship tonnage and travel speed in a given transport situation.
Janusz Ćwiklak, Marek Grzegorzewski and Kamil Krasuski
The article presents the results of research into the use of the differentiation technique of BSSD (Between Satellite Single Difference) observations for the Iono-Free LC combination (Linear Combination) in the GPS system for the needs of aircraft positioning. Within the conducted investigations, a positioning algorithm for the BSSD Iono-Free LC positioning method was presented. In addition, an experimental test was conducted, in which raw observational data and GPS navigation data were exploited in order to recover the aircraft position. The examination was conducted for the Cessna 172 and the on-board dual-frequency receiver Topcon HiperPro. The experimental test presents the results of average errors of determining the position of the Cessna 172 in the XYZ geocentric frame and in the ellipsoidal BLh frame. Furthermore, the article presents the results of DOP (Dilution of Precision) coefficients, the test of the Chi square internal reliability test and the HPL and VPL confidence levels in GNSS precision approach (PA) in air transport. The calculations were performed in the original APS software (APS Aircraft Positioning Software) developed in the Department of Air Navigation of the Faculty of Aeronautics at the Polish Air Force University.
Mirosław Karczewski, Leszek Szczęch and Filip Polak
Cars with electric drive are becoming more fashionable. More and more of them appear on the roads, especially in the centres of big cities. However, electric cars must be charged, preferably from high-power energy sources. In domestic environment, (if somebody owns a house) power available is usually of 10-16 kW. Users have to increase the level of household power or charge the car for several hours, because car charger is not the only home energy receiver. Some of the users are installing energy storage systems solution based on energy storage systems but this require additional expenses for batteries, inverter, circuit breakers and additional equipment. Other disadvantages of such solution are that they are mostly dedicated for stand-alone houses. What could be done by electric cars owners who live on the 10th floor in a block of flats? What would happen if everyone in the same time decided to buy an electric car? What will happen if everyone at the same time charges his or her cars? Do we have an adequate supply of energy potential? On the other hand, do we need to build new energy power plants? Will the electric grid cope with such a load or will have to build new transmission lines, transformer stations, and charging stations?
Wojciech Gis, Maciej Gis, Piotr Wiśniowski and Mateusz Bednarski
Limiting emissions of harmful substances is a key task for vehicle manufacturers. Excessive emissions have a negative impact not only on the environment, but also on human life. A significant problem is the emission of nitrogen oxides as well as solid particles, in particular those up to a diameter of 2.5 microns. Carbon dioxide emissions are also a problem. Therefore, work is underway on the use of alternative fuels to power the vehicle engines. The importance of alternative fuels applies to spark ignition engines.
The authors of the article have done simulation tests of the Renault K4M 1.6 16v traction engine for emissions for fuels with a volumetric concentration of bioethanol from 10 to 85 percent. The analysis was carried out for mixtures as substitute fuels – without doing any structural changes in the engine's crankshafts. Emission of carbon monoxide, carbon dioxide, hydrocarbons, oxygen at full throttle for selected rotational speeds as well as selected engine performance parameters such as maximum power, torque, hourly and unit fuel consumption were determined.
On the basis of the simulation tests performed, the reasonableness of using the tested alternative fuels was determined on the example of the drive unit without affecting its constructions, in terms of e.g. issue. Maximum power, torque, and fuel consumption have also been examined and compared. Thus, the impact of alternative fuels will be determined not only in terms of emissions, but also in terms of impact on the parameters of the power unit.
This study utilized a transparent direct methanol fuel cell, with serpentine channels with a width of 2 mm and an initial depth of 2 mm, and investigated the relationship between the behaviours of carbon dioxide (CO2) slugs, product water accumulations, and voltage fluctuation. It examined the exhaust volumes of CO2 slugs and product water accumulations from the channels over time, comparing an anode channel with a depth of 1.2 mm to one with a depth of 2 mm (without changing the cathode depth of 2 mm, nor the width of 2 mm in both the anode and the cathode). Results indicated that cell voltage fluctuated, rising while CO2 slugs were ejected, and falling between ejections. In the case of an anode channel depth of 2 mm and a lower methanol-water solution flow rate, CO2 slugs were ejected less frequently, so cell voltage fluctuated widely. (Product water accumulations in the cathode had a minimum effect on this cell voltage fluctuation.) In the case of a higher methanol-water solution flow rate, CO2 slugs were ejected more frequently, with less exhaust volume per CO2 slug, reducing the fluctuation in cell voltage. Finally, with an anode channel depth of 1.2 mm, the exhaust volume per CO2 slug became even smaller, and these small CO2 slugs were rapidly ejected. With this shallow depth, the cell voltage increased with a lower methanol-water solution flow rate, but decreased with a higher methanol-water solution flow rate by crossover.
Degradation of the environment is nowadays believed to be the most alarming problem that needs to be solved. Global warming and environmental pollution are predicted to cause a catastrophic chain reaction leading to species extinction, mass emigration due to rising sea levels and global crisis. The only solution suggested by international organizations is the immediate reduction of greenhouse gases and other harmful substances. Marine transportation harmful substances into the atmosphere are recognized to be a significant source of global atmospheric pollution. Despite the high efficiency of marine diesel engines, their impact on the environment is considerable. Due to environmentally friendly policies, modern engines concerns about not only efficiency but also mainly about s aspects. This article analyses and compares marine s exhaust gases reduction methods. Especially the most harmful substances emitted by ships were taken into consideration. The article presents the most crucial law regulations of harmful substances to the atmosphere, pointing at actual and possible future implementations. The most complex methods allowing meeting the latest limits were presented. Pros and cons of available control methods were thoroughly described and methods were compared. The most adequate methods form the effectiveness and economical point of view was pointed out.
Small advanced turboprop and turboshaft engines, with two-stage high-pressure turbine (HPT), need to meet several challenges. Described herein is an exemplary solution adopted for a cantilevered HPT nozzle mounting and sealing system that helped to meet requirements for size constraint and sealing of split lines and mounting features. Since clearances do not scale down with engine size due to manufacturing tolerances, there is a very limited space available between first and second stage rotors to secure HPT nozzle and to provide means of cooling air supply. Due to small diameters, cavities and size of the parts and assembly access becomes very difficult and precluded the use of typical solutions – like supply air spooilers – known from bigger engines. Relatively larger clearances require also efficient solution for sealing leakage, which was achieved by means of high-temperature braided “rope seals”. The nozzle segments have weight effective hook-type outer band mounting to HPT outer casing and are axially retained by HPT shroud with a snap ring. The hook cavities were used as pockets for rope seals that are subsequently compressed during assembly making it more difficult. However, by special design of the pockets and parts engagement sequence, the assembly process was optimized even though it is so called blind assembly. The sealing system function is not only reducing leakages that are detrimental to a turbine efficiency, but also allow for pressurizing the cavity between the nozzle outer band and HPT outer casing with cooling air thus preventing from hot gas ingestion by higher back-flow margin (BFM) resulting in higher durability of the turbine.
In the last two decades, there has been observed a noticeable increase in the popularity and availability of air transport services, including regional ones. This intensive development of transport is accompanied by an increase in the adverse impact to the environment, increases noise level, and exhausts emissions, despite the modification and modernization of engines. Determining the emission for regional flights takes into account the specificity of the aircrafts design, such as the size of the aircraft and the performance of the engines. In this article, an attempt was made to determine the CO2 emissions of a business jet flying from Gdansk to Rzeszow. The methodology of the research (the method of calculating emissions based on fuel consumption) and the performance characteristics of the aircraft engines have been described. In the first part of the article, the speed-altitude characteristics of the DGEN-380 engine for different cruise parameters were determined using the virtual engine test bench WESTT CS/B. These characteristics have enabled the engine to match the flight characteristics (altitude, speed). For specific flight parameters, the thrust and fuel consumption were determined. On this basis, for the adopted trajectory and flight time of an aircraft equipped with two DGEN-380 engines, total fuel consumption and CO2 emission factors and values in CRUISE phase was determined with regard to the wind speed and direction. The obtained results were illustrated graphically and discussed.
In the last decade evolution of the requirements for training and professional competences of ship’s crewmembers, including ship engineers can be observed. Despite the implementation of training programs according to IMO requirements in maritime training centres, a different level of competence of young people beginning their professional career on ships in the engine department is observed. The article discusses general conventions, goals, and effects of the “BS Cadet Program” training program, introduced by one of the larger German ship-owner to improve the competencies of crewmembers at the operational level, who will take duties of the watch engineer in the ship engine room soon. General idea of this training program is reducing the time of the path career what is a standard in most shipping companies. Such idea in this program is utilised by directly merging theoretical knowledge with professional practice on special prepared training vessel. The work present also comparison of the acquired knowledge verification results of training participants with the results of engine cadets from last semester of the UMG Faculty of Engineering. The comparison includes computer exercises of Marine equipment and machineries (UNITEST Company – CBT) also genera ship and engine room knowledge checked by written test called “Final Test” carried out on the end of 3 months training.