scholarly journals A review of split-cycle engines

2018 ◽  
Vol 21 (6) ◽  
pp. 897-914 ◽  
Author(s):  
Joshua Finneran ◽  
Colin P Garner ◽  
Michael Bassett ◽  
Jonathan Hall
Keyword(s):  
Thermal Management ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Engine Design ◽  
Work Assessment ◽  
In Series ◽  
Management Issues

This article reviews split-cycle internal combustion engine designs. The review includes historical work, assessment of prototypes and discussion of the most recent designs. There has been an abundance of split-cycle engine designs proposed since the first in 1872. Despite this, very few prototypes exist, and no split-cycle engines are reported to be in series production. The few split-cycle prototypes that have been developed have faced practical challenges contributing to limited performance. These challenges include air flow restrictions into the expansion cylinder, late combustion, thermal management issues, and mechanical challenges with the crossover valve actuation mechanism. The main promoted advantage of split-cycle engines is the increased thermal efficiency compared to conventional internal combustion engines. However, an efficiency improvement has not thus far been demonstrated in published test data. The thermodynamic studies reviewed suggest that split-cycle engines should be more efficient than conventional four-stroke engines. Reasons why increased thermal efficiency is not realised in practice could be due to practical compromises, or due to inherent architectural split-cycle engine design limitations. It was found that the number of split-cycle engine patents has increased significantly over recent years, suggesting an increased commercial interest in the concept since the possibility of increased efficiency becomes more desirable and might outweigh the drawbacks of practical challenges.

Applying Thermodynamics in Search of Superior Engine Efficiency

2005 ◽  
Vol 127 (3) ◽  
pp. 670-675 ◽  
Author(s):  
Charles A. Amann
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Heat Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Closed Cycle ◽  
Engine Efficiency ◽  
Operating Cycles ◽  
Thermodynamic Processes

Historically, a succession of thermodynamic processes has been used to idealize the operating cycles of internal combustion engines. In this study, the 256 possible combinations of four reversible processes—isentropic, isothermal, isochoric, and isobaric—are surveyed in search of cycles promising superior thermal efficiency. Regenerative cycles are excluded. The established concept of the air-standard cycle, which mimics the internal combustion engine as a closed-cycle heat engine, is used to narrow the field systematically. The approach relies primarily on graphical interpretation of approximate temperature-entropy diagrams and is qualitative only. In addition to identifying the cycles offering the greatest efficiency potential, the compromise between thermal efficiency and mean effective pressure is addressed.

Applying Thermodynamics in Search of Superior Engine Efficiency

2002 ◽  
Author(s):  
Charles A. Amann
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Heat Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Closed Cycle ◽  
Engine Efficiency ◽  
Operating Cycles ◽  
Thermodynamic Processes

Historically, a succession of thermodynamic processes has been used to idealize the operating cycles of internal combustion engines. In this study, the 256 possible combinations of four reversible processes – isentropic, isothermal, isochoric, and isobaric – are surveyed in search of cycles promising superior thermal efficiency. Regenerative cycles are excluded. The established concept of the air-standard cycle, which mimics the internal combustion engine as a closed-cycle heat engine, is used to narrow the field systematically. The approach relies primarily on graphical interpretation of approximate temperature-entropy diagrams and is qualitative only. In addition to identifying the cycles offering the greatest efficiency potential, the compromise between thermal efficiency and mean effective pressure is addressed.

scholarly journals Assessment of thermodynamic cycle of internal combustion engine in terms of rightsizing

2019 ◽  
Vol 178 (3) ◽  
pp. 182-186
Author(s):  
Zbigniew SROKA ◽  
Maciej DWORACZYŃSKI
Keyword(s):  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Internal Combustion ◽  
Research Problem ◽  
Combustion Engines ◽  
Operating Characteristics ◽  
Swept Volume

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.

FEATURES OF MEASURING THE CAMSHAFT OF INTERNAL COMBUSTION ENGINES

2021 ◽  
Vol 4 (30) ◽  
pp. 99-105
Author(s):  
A. V. Summanen ◽  
◽  
S. V. Ugolkov ◽  
Keyword(s):  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Technical Condition ◽  
Combustion Engines

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.

Possibility of using gas lubricant in the cylinders of internal combustion engines of transport vehicles

2021 ◽  
pp. 13-20
Author(s):  
Keyword(s):  
Internal Combustion Engine ◽  
Bearing Capacity ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Engine Piston ◽  
Suspension Stiffness ◽  
Gas Layer

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]

Calculation of Acoustic Efficiency of Exhaust Silencers for Automotive Internal Combustion Engines

2021 ◽  
pp. 41-47
Author(s):  
Vladimir Tupov ◽  
O. Matasova
Keyword(s):  
Acoustic Waves ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Control Point ◽  
Plane Waves ◽  
Exhaust System ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Exhaust Noise ◽  
Insertion Losses

Insertion losses as the main characteristic that mathematically describes the acoustic efficiency of a noise silencer has been considered. This characteristic shows the reduction of noise generated by its source, in particular by the internal combustion engine’s exhaust system, at the control point as a silencer use result. Has been presented a mathematical description of the insertion losses, and have been considered parameters necessary for calculating this characteristic. Has been demonstrated the analytical dependence of impedance for the sound emission by the exhaust system’s end hole from the coefficient of acoustic waves reflection by this hole. The performed analysis of the widely used formulas for calculating the coefficient of sound reflection by the end hole has showed their insufficient accuracy for project designs performing. Have been proposed calculation dependences providing high accuracy for calculations of the reflection coefficient modulus, and the attached length of the channel end hole without a flange in the entire range of the existence of plane waves in it. It has been shown that the end correction of this hole at ka = 0 is 0.6127, and not 0.6133, as it was mistakenly believed until now in world acoustics. Has been proposed a method for calculation the exhaust noise source internal impedance. This method more accurately, in comparison with the already known ones, describes the acoustic processes in the internal combustion engine’s exhaust manifold, thanks to increases the accuracy of calculation the silencer acoustic efficiency, that allows develop the silencer at the early stages of the design of an automotive internal combustion engine.

A Novel Way of Manipulating and Optimizing CAM Profiles for Internal Combustion Engines

2007 ◽  
Author(s):  
Satheesh Makkapati ◽  
Kim Ku ◽  
Steve Poe
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Computationally Efficient ◽  
Trade Offs ◽  
Cam Profile ◽  
Computer Codes ◽  
Tool Optimization ◽  
Automated Tool

Generating an optimum cam profile for an internal combustion engine application is usually a very involved process. This is because of the challenge faced by the engine engineers to perform several trade-offs between fuel economy, performance, durability and emissions. Typically, the trade offs are worked out using several computer codes and with the involvement of a cross-functional team of engineers. Hence, there is a need to develop a tool that can encapsulate the various computer codes and can manipulate the cam profile with ease. With the existence of such an automated tool, optimization of the cam profile can be achieved with a specified trade-off between the several metrics identified above. This paper describes the development of such a tool, and discusses the ingredients that make it flexible and computationally efficient. Results from the use of this tool are documented in this paper as well.

Performance study of the hypocycloid gear mechanism for internal combustion engine applications

2019 ◽  
pp. 146808741989358 ◽  
Author(s):  
Mostafa A ElBahloul ◽  
ELsayed S Aziz ◽  
Constantin Chassapis
Keyword(s):  
Internal Combustion Engine ◽  
Thermodynamic Model ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Otto Cycle ◽  
Engine Efficiency ◽  
Gear Mechanism ◽  
Crank Mechanism

Fuel conversion efficiency is one of the main concerns in the field of internal combustion engine systems. Although the Otto cycle delivers the maximum efficiency possible in theory, the kinematics of the slider–crank mechanism of the conventional internal combustion engines makes it difficult to reach this level of efficiency in practice. This study proposes using the unique hypocycloid gear mechanism instead of the conventional slider–crank mechanism for the internal combustion engines to increase engine efficiency and minimize frictional power losses. The hypocycloid gear mechanism engine’s kinematics provides the means for the piston-rod assembly to reciprocate in a straight-line motion along the cylinder axis besides achieving a nonlinear rate of piston movement. As a result, this characteristic allows for a true constant-volume combustion, which in turn would lead to higher work output. An in-cylinder gas volume change model of the hypocycloid gear mechanism engine was developed and incorporated into the thermodynamic model for the internal combustion engine cycle. The thermodynamic model of the hypocycloid gear mechanism engine was developed and simulated using MATLAB/Simulink software. A comparison between the conventional engine and the hypocycloid gear mechanism engine in terms of engine performance characteristics showed the enhancements achieved using hypocycloid gear mechanism for internal combustion engine applications. The hypocycloid gear mechanism engine analysis results indicated higher engine efficiency approaching that of the Otto cycle.

scholarly journals The Impact of Powering an Engine with Fuels from Renewable Energy Sources including its Software Modification on a Drive Unit Performance Parameters

2019 ◽  
Vol 11 (23) ◽  
pp. 6585 ◽  
Author(s):  
Markiewicz ◽  
Muślewski
Keyword(s):  
Renewable Energy ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Renewable Energy Sources ◽  
Internal Combustion ◽  
Energy Sources ◽  
Exhaust Emission ◽  
Combustion Engines ◽  
Performance Parameters ◽  
The Impact

The application of fuels from renewable energy sources for combustion engine powering involves a great demand for this kind of energy while its production infrastructure remains underdeveloped. The use of this kind of fuel is supposed to reduce the emission of greenhouse gases and the depletion of natural resources and to increase the share of renewable energy sources in total energy consumption and thus support sustainable development in Europe. This study presents the results of research on selected performance parameters of transport by internal combustion engines including: power, torque, the emission of sound generated by the engine, the content of exhaust components (oxygen O2, carbon monoxide CO, carbon dioxide CO2, nitrogen dioxide NO2), and the content of particulate matter (PM) in exhaust emission. Three self-ignition engines were tested. The fuel injection controllers of the tested internal combustion engines were additionally adjusted by increasing the fuel dose and the load of air. The material used in the tests were mixtures of diesel oil and fatty acid methyl esters of different concentration. A statistical analysis was performed based of the results. The purpose of the work was to develop a resulting model for assessing the operation of engines fueled with biofuel and diesel mixtures while changing the vehicle's computer software. A computer simulation algorithm was also developed for the needs of the tests which was used to prognose the state of the test results for variable input parameters.

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