The article presents results of operation investigations regarding one of the most important receivers of mechanical energy on dredgers: propellers. Operation investigations covered measurements of characteristic parameters of loading propellers on dredgers in two basic conditions of their work: dredging works and sailing at sea. Presented results are based on 10 dredgers (8 trailing suction hopper dredgers and 2 bucket dredgers). In the paper characteristics of spread of propellers loading, i.e. average value, standard deviation and coefficients of variations of loading spred are presented. Examples of load distribution propellers on chosen dredgers during some period of time are shown as well. Conclusions are formulated regarding average value of propellers loading and coefficients of variations of loading spred. Results presented in the paper will be used as a base for creation of random models describing real conditions of operation of dredgers’ power plants.

In the paper has been make an attempt to replace the conventional system of fuel dose control and injection passing angle with the elecrtronic control system, which has been realized this manner, that selected hydraulic accumulator, injector CR type and fuel dose controller has been attached to the marine engine. It has been as-sumed, that by controlling the current impulse of controller it is possible to model whichever size of fuel dose, injected to the combustion chamber and to control the injection lasting time. It has been presented the simplistic scheme of test stand and it has been described the basis of fuel dose controlling valve operation in the injector. The wave phenomenon and the flow loss in the fuel pipe of high pressure have been presente

The paper presents description of biogas utilization as a renewable energy source used for fueling cogeneration generating sets with IC engines. There are presented similarities of such systems to marine power plants and connected with this some propositions about utilization marine knowledge and experiences for developing polish decentralized engineering with biogas power plants

The paper presents cutting forces simulation method for valve seats machining. Cutting forces affecting on tool used for valve seats machining and mathematical relations used for simulating forces were described. Tool used for valve seats machining was presented and machining process was described. Analysis of tool setting against machined valve seat impact on area of the chip on tool blades was made by simulation. Simulated cutting forces for different tool settings against machined valve seat were presented. Test stand for verifying simulated cutting forces against measured cutting forces was characterized. General conclusions arising from simulations and further research plans were presente

The paper presents case of tool damage during valve seat machining process. The tool for valve seats machining was described, details of tool damage were characterized. Damage was illustrated by wrongly machined (destroyed) valve seat, cutting forces for correct valve seat machining and cutting forces for tool destruction case. For analysis was used LVDT contact sensor. General conclusions arising from tool damage process observation were presente

This paper deals with experimental selection of a cooling system of a brushless synchronous generator with permanent magnets and an additional excitation, designed and built in Department of Ship Electrical Power Engineering in Gdynia Maritime University. Three cooling system were tested: with an aluminium radiator and natural cooling with the aluminium radiator and an external fan and the aluminium radiator and two external fans. Results of thermal tests are presented for a machine with built-in thermocouples. The selection of cooling system for the investigated machine is based on the experimental results

In the paper has been described the Common Rail system, which operation is presented on the example of engine RT-flex 60C type. Three basic circuits have been dispersed in this system: low pressure circuit, high pressure circuit and electronically controlled system, but only low pressure circuit and high pressure circuit were discussed. Wave phenomena and fuel loss in the fuel pipe have been presented as an example of complex processes, which occur in the fuel apparatus of high pressure. For the description of shock waves disperse there has been considered the wave flow in thecentre, which fills the long pipe with variable section. The Euler’s equation, adiabatic equation and continuity equation were used to describe such flow. Advantages and disadvantages of the storage systems with fuel injection unit have been discussed in the resume

The paper presents proposal of scope of control surface for marine power plant of merchant ship, being an element of ship’s energy system and consists of devices and energy plants exchanging fuel energy into other kind of energy, auxiliary devices and others irrelevant to the energy conversion processes, but indispensable because of international safety at sea and environmental protection provisions. Accepted scope of control surface allows to derive useful energy, or total generated minus energy consumed for autonomous shipping, this is why the suggested term “autonomous ship’s power plant”. This way makes possible (among others) valuation of results of waste heat recovery system used on boar

Based on measurement results, an interpretation is presented of the tribological system boundary layer action in the form of a four-ball tester friction node. The evaluation was performed of the boundary layer action understood as transfer of energy Ep resulting from loading the tribological system in a determined time t with work lp, which may lead to breaking the boundary layer. That energy and time are the values unequivocally characterising the boundary layer action. This form of presenting the boundary layer action has also an advantage of offering a possibility of investigating it by carrying out precise measurements and expressing the results in a numerical form. Therefore, the proposed method of evaluating the boundary layer action deterioration process is the acoustic emission measurements

W artykule przeanalizowano przyczyny błędnego wykorzystania wskaźnika produktu krajowego brutto (PKB) przy ocenie wielkości i tempa wzrostu wytwarzanej w kraju produkcji. Z tych samych powodów wskaźnik PKB nie jest przydatny w ocenie efektywności prowadzonej w kraju polityki inwestycyjnej i inno-wacyjnej. Zaleca się zamianę wskaźnika PKB na wskaźnik dochodu krajowego brutto (DKB) i podaje się je-go definicję

Combinatorial method of an assessment of management object state is suggested according to the situational symptoms of the forecast behavior based on probabilistic solutions

The paper presents the problems of fighting the noise coming from hydraulic central loading systems with big power installed on modern product and chemical tankers to supply cargo pumps. The structure of a hydraulic central loading system is described along with its components and main noise sources are characterized. Active and passive ways of noise reduction on a technical road are presented as well. All the deliberations have been illustrated on the example of specific solutions of the hydraulic central loading system installed on the product tanker m/t “Helix”, built by the Szczecin Shipyard SA for the Shell-Australia shipowner

W artykule omówiono podstawowe problemy polskiego transportu samochodowego w zakresie przewozu ładunków. Wskazano na dominujący udział tego środka transportu w przewozach krajowych, przy jednoczesnym zaniedbaniu infrastruktury i niskiej sprawności techniczno-eksploatacyjnej taboru samochodowego. Poruszono też temat wymogów narzuconych wejściem Polski do Unii Europejskiej, a także zależności między rozwojem gospodarki narodowej a rozwojem systemu transportowego, które wymagają podjęcia jak najszybszych działań

W polityce transportowej, a także w praktyce gospodarczej od lat prowadzona jest debata nad liberalizacją czy kontrolowanym ładem współzawodnictwa na rynku usług transportowych. Przyczyny owego sporu leżą nie w istniejącym ładzie rynkowym transportu lub w zmieniających się wymaganiach wynikających z potrzeb przewozowych, ale uzasadniane są zróżnicowanym punktem widzenia określonej polityki gospodarczej. W artykule wskazano na teorie gospodarcze i konkurencyjne w debacie nad regulacją i deregulacją w transporcie, w której dużo mówi się o deregulacji, a zbyt mało o regulacji procesów transportowych

The article presents creation of a methodology of intertrade planning free from any defects connected with the usage of the V. Leontjev economical mathematical model and “Input – Output” intertrade balance [1, 2]. A new type of an intertrade balance (BMB “P-P”) has been drawn up as well as an algorithm of its optimization imitating the mechanism of the market regulation and allowing an imitation of various commercial production demand conditions. The possibility of a BMB “P-P” optimization is unique because no other algorithms for the solution of this problem or for the production plans construction exist that are counterbalanced with the possibilities of the production on a country’s scale. The utilization of the proposed methodology will allow avoiding the shortcomings, minimizing the costs, estimating social and economic realization efficiency of innovation projects, determining the realization effects of state investment programs and protectionist decisions of country’s management, as well as forecasting changes in the proportion of intertrade production