Combustion Heat Engines Research Articles

New About the Balancing of Thermal Motors

The paper presents a new method of balancing the thermal motors, the method that perfectly fits the engines with modern internal combustion. This new constructive method imposes a new in-line engine design in order to better balance it, thus achieving a static balancing and total dynamics of the new type of internal combustion heat engine. The method can also be extended to external combustion thermal engines.

New About the Balancing of Thermal Motors

The paper presents a new method of balancing the thermal motors, the method that perfectly fits the engines with modern internal combustion. This new constructive method imposes a new in-line engine design in order to better balance it, thus achieving a static balancing and total dynamics of the new type of internal combustion heat engine. The method can also be extended to external combustion thermal engines.

Numerical investigations on the Dish–Stirling engine system

ABSTRACTThe Stirling engine is an environmentally friendly external combustion heat engine and reduces the complexities of the combustion process, and indirectly helps in reduction of CO2 emission. Modelling based on cyclic analysis is performed for a Beta configuration Stirling engine of 1.5 kWe capacity using a rhombic drive for the solar-dish-supported Stirling engine. The analysis helps in estimating the overall efficiency of the system using the experimental correlation of the solar concentrator ARUN160 at the engine operating temperature. The analysis shows that the system will have overall efficiency around 25% in the range of 750–1050 K at the expansion space. The degradation of performance compared to that at an operating temperature of 1025 K is only marginal and makes 750 K a more preferred temperature. The present study evaluates a range of possible design goals and provides suitable alternatives and thus provides a clear understanding of the system design considerations.

Development of a 5 kW traveling-wave thermoacoustic electric generator

Traveling-wave thermoacoustic heat engine is a new type of external combustion heat engine, which is capable of converting thermal energy to acoustic power with advantage of heat source flexibility, reliability and efficiency. The generated acoustic power will be further converted into electricity by connecting linear alternator with the engine. This power generation system is called traveling-wave thermoacoustic electric generator. In this paper, a new traveling-wave thermoacoustic electric generator is proposed, which consists of a multi-stage traveling-wave thermoacoustic heat engine and linear alternators. The engine has several units connected end-to-end by slim resonance tubes to obtain a traveling-wave acoustic field in the regenerator, which is required by an efficient thermoacoustic heat engine. The alternator is connected as a bypass at the end of each resonance tube. Here, a three-stage traveling-wave thermoacoustic electric generator was developed. In the experiments, the maximum electric power of 4.69kW with thermal-to-electric efficiency of 15.6% and the maximum thermal-to-electric efficiency of 18.4% with electric power of 3.46kW were achieved with 6MPa pressurized helium, 650°C and 25°C heating and cooling temperatures. Additionally, the influence of the electric capacitance on the system performance was investigated, which may provide some clue to couple the alternator with the engine. So far, this performance is the best one of such type of machines. It is believed that this technology will be suitable for many applications in the energy area, such as solar energy, industrial waste heat and so on.

MACHINE MOTION EQUATIONS

This paper presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates angular speed of the shaft (which varies with position and rotation speed) is deduced by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic D (generated by the forces out of mechanism and or by the forces generated by the elasticity of the system). Kinetic energy conservation shows angular speed variation (from the shaft) with inertial masses, while the dynamic coefficient introduces the variation of w with forces acting in the mechanism. Deriving the first equation of motion of the machine one can obtain the second equation of motion dynamic. From the second equation of motion of the machine it determines the angular acceleration of the shaft. It shows the distribution of the forces on the mechanism to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. Calculations should be made for an engine with a single cylinder. Originally exemplification is done for a classic distribution mechanism, and then even the module B distribution mechanism of an Otto engine type.

Machine Motion Equations at the Internal Combustion Heat Engines

This paper presents an algorithm for setting the dynamic parameters of the classic main mechanism of the internal combustion engines. One presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates angular speed of the shaft (which varies with position and rotation speed) is deduced by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic (generated by the forces out of mechanism). Kinetic energy conservation shows angular speed variation (from the main shaft) with inertial masses, while the dynamic coefficient introduces the variation of ω with forces acting in the mechanism. Deriving the first equation of motion of the machine it obtains the second equation of motion dynamics. From the second equation of motion of the machine one determines the angular acceleration of the motor shaft. It shows the distribution of the forces (on the main mechanism of the engine) to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. The method is applied separately for two distinct situations: When the engine is working on a compressor and into the motor system. For the two separate cases, two independent formulas are obtained for the engine dynamic cinematic (forces speeds). Calculations should be made for an engine with a single cylinder.

Machine Equations to the Classical Distribution

This paper presents an algorithm for setting the dynamic parameters of the classical distribution mechanism of the internal combustion engines. One presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates angular speed of the camshaft (which varies with position and rotation speed) is deduced by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic D (generated by the forces out of mechanism). Kinetic energy conservation shows angular speed variation (from the cam shaft) with inertial masses, while the dynamic coefficient introduces the variation of  with forces acting in the mechanism. Deriving the first equation of motion of the machine we obtain the second equation of motion dynamics. From the second equation of motion of the machine we determine the angular acceleration of the camshaft. It shows the distribution of the forces on the cam shaft mechanism to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. Calculations should be made for an engine with a single cylinder

Determination of the Yield of Internal Combustion Thermal Engines

This paper presents an algorithm for setting the dynamic parameters of the classic main mechanism of the internal combustion engines. It shows the distribution of the forces (on the main mechanism of the engine) to the internal combustion heat engines. With these strengths, and together with velocities of kinematic couplings is established then the heat engine efficiency. The method is applied separately for two distinct situations: when the engine is working on a compressor and into the motor system. For the two separate cases, two independent formulas are obtained for the engine yield. With these relationships are then calculated about mechanical efficiency of Otto heat engine, four stroke, two-stroke and 4-stroke V. Final yield of the engine is obtained considering and thermal efficiency given by Carnot cycle

Analysis of the characteristics of external combustion heat engine by computer simulation

The article is about the mathematical model, which is used for development of a computer model of the heat engine with external combustion. Computer simulation allowed to establish main principles of heat engine operation and make the analysis of the impact of changes on its characteristics and develop variant of the engine design.

Possible future scenarios for atmospheric concentration of greenhouse gases: A simplified thermodynamic approach

Most of the increase in concentrations of greenhouse gases in the Earth's atmosphere is mainly due to anthropogenic activities. This is particularly significant in the case of CO 2. The atmospheric concentration of CO 2 has systematically increased since the Industrial Revolution (260 ppm), with a remarkable raise after the 1970s until the present day (380 ppm). If this increasing tendency is maintained, the last report of the Intergovernmental Panel on Climate Change (IPCC) estimates that, for the year 2100, the CO 2 concentration can augment up to approximately 675 ppm. In this work it is assumed that the quantity of anthropogenic greenhouse gases emitted to the Earth's atmosphere is proportional to the quantity of heat rejected to the environment by internal combustion heat engines. It is also assumed that this increasing tendency of CO 2 due to men's activity stems from a mode of energy production mainly based on a maximum-power output paradigm. With these hypotheses, a thermoeconomic optimization of a thermal engine model under two regimes of performance: the maximum-power regime and the so-called ecological function criterion is presented. This last regime consists in maximizing a function that represents a good compromise between high power output and low entropy production. It is showed that, under maximum ecological conditions, the emissions of thermal energy to the environment are reduced approximately up to 50%. Thus working under this mode of performance the slope of the curves of CO 2 concentration, for instance, drastically diminishes. A simple qualitative criterion to design ecological taxes is also suggested.