Efficiency of energy conversion using shock waves

1985 ◽  
Vol 63 (3) ◽  
pp. 339-345
Author(s):  
J. M. Dewey ◽  
D. J. McMillin

The flux-corrected transport algorithm has been used to simulate shock-wave flows in linear and spherically converging and diverging tubes in order to determine the energy distributions in the flows and the conversion efficiencies of energy to mechanical work. This was done to evaluate the possibility of using the positive phase of a shock wave, rather than combustion products, as the driving mechanism in an internal-combustion engine, and to suggest the optimum configuration of a supercharging device that uses shock waves to extract energy from the exhaust gases of internal-combustion engines. It is concluded that the positive phase of a shock wave would not be especially useful as the primary driving mechanism of an internal-combustion engine. In the case of the supercharging energy exchangers, the simulations indicate that for charging pressure ratios lower than about 5:1, a linear tube with a compression-chamber length of about 40% would be most efficient, while at higher pressure ratios a converging conical tube with a compression-chamber length of about 10% would be preferred.

1988 ◽  
Vol 54 (498) ◽  
pp. 527-531 ◽  
Author(s):  
Noriaki SEKINE ◽  
Shuji MATSUMURA ◽  
Kazuyoshi TAKAYAMA ◽  
Osamu ONODERA ◽  
Katsuhiro ITO

Author(s):  
Jiang Lu ◽  
Ashwani K. Gupta ◽  
Eugene L. Keating

Abstract Numerical simulation of flow, combustion, heat release rate and pollutants emission characteristics have been obtained using a single cylinder internal combustion engine operating with propane as the fuel. The data are compared with experimental results and show excellent agreement for peak pressure and the rate of pressure rise as a function of crank angle. The results obtained for NO and CO are also found to be in good agreement and are similar to those reported in the literature for the chosen combustion chamber geometry. The results have shown that both the combustion chamber geometry and engine operating parameters affects the flame growth within the combustion chamber which subsequently affects the pollutants emission levels. The code employed the time marching procedure and solves the governing partial differential equations of multi-component chemically reacting fluid flow by finite difference method. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution levels. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.


2020 ◽  
Vol 6 (2) ◽  
pp. 146-151
Author(s):  
Ihor Holovach ◽  
◽  
Lidiia Kasha ◽  
Ivan Hudzii

The article analyses the modern lubrication systems for internal combustion engines. Systems with mechanical drive components that contain mechanical and electronic components have been found to have a number of disadvantages. In particular, when the internal combustion engine is started cold, when the viscosity of the oil is high, the hydrodynamic resistance characteristic rises sharply, which leads to high pressure at low speeds and the drive requires low pump speeds. Again, the increase in oil temperature causes a decrease in viscosity, the hydrodynamic resistance characteristic becomes flatter. This, in turn, reduces the pressure in the lubrication system and requires an increase in pump speed in order to keep the pressure constant. Based on the analysis, the requirements for lubrication systems are formulated and a separate lubrication system with forced oil supply is proposed in this paper. For the drive of pump lubrication system of the internal combustion engine, a switched reluctance motor is proposed and calculated. Such motor by its qualities is one of the most useful in this type of systems.


2019 ◽  
Vol 178 (3) ◽  
pp. 182-186
Author(s):  
Zbigniew SROKA ◽  
Maciej DWORACZYŃSKI

The modification of the downsizing trend of internal combustion engines towards rightsizing is a new challenge for constructors. The change in the displacement volume of internal combustion engines accompanying the rightsizing idea may in fact mean a reduction or increase of the defining swept volume change factors and thus may affect the change in the operating characteristics as a result of changes in combustion process parameters - a research problem described in this publication. Incidents of changes in the displacement volume were considered along with the change of the compression space and at the change of the geometric degree of compression. The new form of the mathematical dependence describing the efficiency of the thermodynamic cycle makes it possible to evaluate the opera-tion indicators of the internal combustion engine along with the implementation of the rightsizing idea. The work demonstrated the in-variance of cycle efficiency with different forms of rightsizing.


2021 ◽  
Vol 4 (30) ◽  
pp. 99-105
Author(s):  
A. V. Summanen ◽  
◽  
S. V. Ugolkov ◽  

This article discusses the issues of assessing the technical condition of the camshaft, internal combustion engine. The necessary parameters for assessing the technical condition of the engine camshaft have been determined. How and how to measure and calculate this or that parameter is presented in detail. Methods for calculating the parameters are presented. A scheme and method for measuring neck wear, determining the height of the cam, determining the beating of the central journal of the camshaft are proposed. The main defects of the camshafts are presented. The issues of the influence of these parameters on the operability of the camshaft and the internal combustion engine as a whole are considered.


2021 ◽  
pp. 13-20
Author(s):  

The prospects of using the gas-static suspension of the internal combustion engine piston in transport vehicles and power plants are considered. The diagram of the piston and the method for calculating the stiffness and bearing capacity of the gas layer surrounding the piston are presented, as well as the results of experiments that showed the relevance of this method. The possibility of gas and static centering of the engine piston is confirmed. Keywords: internal combustion engine, piston, gasstatic suspension, stiffness, bearing capacity, gas medium. [email protected]


Author(s):  
E.T. Plaksina ◽  
A.B. Syritsky ◽  
A.S. Komshin

The article considers the main methods of internal combustion engine diagnostics. A method based on measuring the time intervals between the phases of the working cycle of the mechanism is described. An algorithm for measuring the time intervals from the formulation of the problem to the proof of the efficiency of this method on an internal combustion engine has been determined. The installation of the angle sensor on the crankshaft of the experimental bench engine VAZ 21126 is shown. The basis for the construction of a mathematical model of the crankshaft is presented and the main factors influencing its movement are identified. A criterion has been established according to which the misfire is determined most accurately. The results obtained can be used for developing diagnostic systems for internal combustion engines, as well as engines operating in extreme conditions, for example, beyond the Arctic Circle, on ships, etc.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2362
Author(s):  
Savvas Savvakis ◽  
Dimitrios Mertzis ◽  
Elias Nassiopoulos ◽  
Zissis Samaras

The current paper investigates two particular features of a novel rotary split engine. This internal combustion engine incorporates a number of positive advantages in comparison to conventional reciprocating piston engines. As a split engine, it is characterized by a significant difference between the expansion and compression ratios, the former being higher. The processes are decoupled and take place simultaneously, in different chambers and on the different sides of the rotating pistons. Initially, a brief description of the engine’s structure and operating principle is provided. Next, the configuration of the compression chamber and the sealing system are examined. The numerical study is conducted using CFD simulation models, with the relevant assumptions and boundary conditions. Two parameters of the compression chamber were studied, the intake port design (initial and optimized) and the sealing system size (short and long). The best option was found to be the combination of the optimized intake port design with the short seal, in order to keep the compression chamber as close as possible to the engine shaft. A more detailed study of the sealing system included different labyrinth geometries. It was found that the stepped labyrinth achieves the highest sealing efficiency.


1993 ◽  
Vol 115 (4) ◽  
pp. 694-701 ◽  
Author(s):  
Jiang Lu ◽  
Ashwani K. Gupta ◽  
Eugene L. Keating

Numerical simulation of flow, combustion, heat release rate, and pollutants emission characteristics have been obtained using a single cylinder internal combustion engine operating with propane as the fuel. The data show that for good agreement with experimental results on the peak pressure and the rate of pressure rise as a function of crank angle, spark ignition energy and local cylinder pressure must be properly modeled. The results obtained for NO and CO showed features which are qualitatively in good agreement and are similar to those reported in the literature for the chosen combustion chamber geometry. The results have shown that both the combustion chamber geometry and engine operating parameters affects the flame growth within the combustion chamber which subsequently affects the pollutants emission levels. The code employed the time marching procedure and solves the governing partial differential equations of multicomponent chemically reacting fluid flow by finite difference method. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution levels. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.


Author(s):  
David R. Buttsworth ◽  
Abdalla Agrira ◽  
Ray Malpress ◽  
Talal Yusaf

Simulation of internal combustion engine heat transfer using low-dimensional thermodynamic modelling often relies on quasi-steady heat transfer correlations. However, unsteady thermal boundary layer modelling could make a useful contribution because of the inherent unsteadiness of the internal combustion engine environment. Previous formulations of the unsteady energy equations for internal combustion engine thermal boundary layer modelling appear to imply that it is necessary to adopt the restrictive assumption that isentropic processes occur in the gas external to the thermal boundary layer. Such restrictions are not required and we have investigated if unsteady modelling can improve the simulation of crank-resolved heat transfer. A modest degree of success is reported for the present modelling which relies on a constant effective turbulent thermal conductivity. Improvement in the unsteady thermal boundary layer simulations is expected in future when the temporal and spatial variation in effective turbulent conductivity is correctly modelled.


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