Jacek Kropiwnicki

Causality in Models of Thermal Processes in Ship Engine Rooms with the Use of Bond Graph (BG) Method

Abstract With a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented [2] new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality in models of thermal processes created by the said concept were given. The analysis of causality makes it possible to demonstrate the model conflicts that prevent the placement of state equations which allows for the direct conduct of simulation experiments. Attention has been drawn to the link between the energy systems models of thermal processes with models of elements of different physical nature. Two examples of determining causality in models of complex energy systems of thermal elements have been presented. The firs relates to the electrical system associated with the process of heat exchange. The second is a model of the mechanical system associated with the thermodynamic process.

Analysis of the possibility of determining the general characteristics using the operational data of a vehicle engine

The paper presents an analysis of the possibility of determining the general characteristics using the operational data of an engine of refuse collection vehicle. Data acquisition was done by reading information from the CAN network using FMS standard (Fleet Management System), which is widely used in heavy duty vehicles since year 2002. The paper presents the analysis of the expected measurement uncertainties resulting from the standard PN_ISO 15550-2009. The experimental data were filtered due to the established constraints that define the static states of the engine. On the basis of the obtained measurement data, corresponding to various defined static states, the general characteristics of the engine were made and discussed.

Stirling Engines Powered by Renewable Energy Sources

Stirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy sources, including renewable energy sources. Commercial devices for electric power generation offered for use in home, usually do not exceed 1 kW. Using the Schmidt model, the analyze of influence of temperature working fluid in the expansion space (heater) on the efficiency and the electric power generated in the Stirling engine of alpha type has been presented in the paper.

A Model of Thermal Energy Storage According to the Convention of Bond Graphs (Bg) and State Equations (Se)

Abstract The main advantage of the use of the Bond Graphs method and State Equations for modeling energy systems with a complex structure (marine power plants, hybrid vehicles, etc.) is the ability to model the system components of different physical nature using identical theoretical basis. The paper presents a method of modeling thermal energy storage, which is in line with basic BG theory. Critical comments have been put forward concerning multiport energy storage introduced by other authors or the so-called C-field. In suggested approach, the decision not to use pseudo Bond Graphs has been justified as not being in line with basic BG theory. On the basis of molecular physics it was considered that the state variable, in physical and mathematical sense, should be temperature rather than entropy. Examples of the application of the proposed approach to thermodynamic processes and heat exchange have been presented. The application of a single graph as a model for thermal energy storage has been illustrated by a way of numerical simulation examples.

The Initial Selection of Parameters for Dynamic Brake for Car Engine Test Dynamometer

The article presents an analysis of the car engine loads. The aim of the analysis was to determine the parameters of the brake / electric motor on an engine test bad. Analysis of loads on the driving tests concerned on chassis dynamo to simulate them on an engine dynamometer. To check the range of dynamometer shaft angular acceleration inertial mass of a car was reduced on the crankshaft axis. The calculations of maximum shaft acceleration were performed. Also the whole car acceleration when pulling away from the place was calculated. Calculations were verified by experiment on road. They both gave a good agreement.

Carbon Dioxide Potential Reduction Using Start-Stop System in a Car

Operating fuel consumption increases significantly when the vehicle stops frequently while driving or when the engine is idling during braking. In such cases, the internal combustion engine consumes the fuel but the mechanical energy is not used by the drive system. The amount of fuel that is consumed in this time by the engine can potentially be saved if the car is equipped with a Stop-Start system. Start-Stop system automatically shuts down and restarts the internal combustion engine due to strategy used by controller reducing this way toxic compounds emissions in exhaust gasses and the fuel consumption, which is directly connected to carbon dioxide (CO2) emissions. The paper presents an analysis of the potential reduction in CO2 emissions for selected vehicles with Start-Stop system during operation in selected urban agglomeration using different strategies to control this system. The study was carried out using numerical models of propulsion systems. The results were compared with the statistical data derived from regular use of vehicles equipped with such a system.