Modifications to the Method of Characteristics for the Analysis of the Gas Exchange Process in Internal Combustion Engines

1986 ◽  
Vol 200 (4) ◽  
pp. 259-266 ◽  
Author(s):  
F Payri ◽  
J M Corberán ◽  
F Boada
Keyword(s):  
Gas Exchange ◽  
Internal Combustion Engines ◽  
Method Of Characteristics ◽  
Exchange Process ◽  
Internal Combustion ◽  
Linear Interpolation ◽  
Combustion Engines ◽  
The Method Of Characteristics ◽  
Grid Points ◽  
Gas Exchange Process

Some modifications to the method of characteristics for the analysis of the gas exchange process in internal combustion engines are presented in this paper. The modifications are related to the calculation of the path lines and the Riemann characteristic lines at the grid points. Regarding the path lines, the algorithm for the generation and elimination of path lines has been improved, mainly for the cases in which the fluid motion passes from being null or going out of the pipe to going into the pipe. In those cases the algorithm proposed by Benson can cause some mistakes in the entropy level field of the duct. An alternative method is proposed: the duplication ofpath lines. The other modifcation proposed is related to assuming a linear interpolation for the pressure and the volume flowrate between the nearest grid points, rather than assuming a linear interpolation of the value of the Riemann characteristics. These modijcations substantially improve the results obtained in the calculation of the fluid flow in manifolds of reciprocating internal combustion engines.

Paper 11: Computing the Gas Exchange Process of Pressure Charged Internal Combustion Engines

1967 ◽  
Vol 182 (12) ◽  
pp. 109-118 ◽  
Author(s):  
M. Ryti
Keyword(s):  
Gas Exchange ◽  
Internal Combustion Engines ◽  
Exchange Process ◽  
Computing Time ◽  
Linear Wave ◽  
Combustion Engines ◽  
Practical Application ◽  
Wide Range ◽  
Gas Exchange Process ◽  
Wave Phenomena

Numerous problems associated with pressure charging can only be solved numerically by analysing the gas exchange process. The extensive practical application of step by step calculations of the process has only become possible with the advent of digital computers. For fundamental investigations the data provided by quasi-steady-state calculations are quite adequate, the amount of computing time being only a fraction of that needed for calculations in which allowance is made for non-linear wave phenomena. The Turbocharger Department of Brown Boveri utilizes a digital computer for calculations involving the gas exchange process in conjunction with its consulting activity for the benefit of customers. The program can be adapted to solve a very wide range of problems. The procedure is briefly described and possible applications discussed with reference to the following practical examples. Optimization of valve timing. Assessment of the results from various aspects. Performance and design for high pressure turbocharging and for high-altitude installations. Two-stage turbocharging. Mixture control for dual-fuel and gas engines.

Paper 3: Non-Steady Flow in Internal Combustion Engine Inlet and Exhaust Systems

1969 ◽  
Vol 184 (7) ◽  
pp. 7-16 ◽  
Author(s):  
R. S. Benson ◽  
J. S. Foxcroft
Keyword(s):  
Standard Deviation ◽  
Steady Flow ◽  
Internal Combustion Engines ◽  
Method Of Characteristics ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Steady Flows ◽  
The Method Of Characteristics ◽  
Mass Flows ◽  
Exhaust Systems

Previous work on non-steady flow in exhaust systems has shown that the method of characteristics can be used to predict the flow conditions to a high degree of accuracy. In these calculations the pressure at the inlet port or valve was considered to be constant. Recent work on the effect of pulsating flow on centrifugal compressors has shown the importance of considering non-steady flows in the inlet systems of supercharged engines. Predictions of the non-steady flow in inlet systems, usually based on acoustic theory, have only been accurate in particular cases. In this paper the method of characteristics has been applied to the study of non-steady flows both in the inlet and exhaust systems of internal combustion engines. Comparisons are made between the calculated and experimental results obtained on a multi-cylinder pulse generator. Tests on both single- and two-cylinder units were carried out and measurements of the inlet pipe pressure, exhaust pipe pressure, cylinder pressures and temperatures, and inlet and exhaust mass flows were made. Comparisons between the theoretical predictions and the test results were extremely good; in all the cases the pressures were in close agreement. The inlet predicted mass flows were all within +9 and −4 per cent of the measured flows, the standard deviation being 3·1 per cent. The exhaust mass flows were all within +8 and −12 per cent of the measured mass flows, the standard deviation being 4·3 per cent. It was considered that the method gives reliable predictions of the flow processes in internal combustion engines.

LES of the Gas-Exchange Process Inside an Internal Combustion Engine Using a High-Order Method

2019 ◽  
Vol 104 (2-3) ◽  
pp. 673-692 ◽  
Author(s):  
G. K. Giannakopoulos ◽  
C. E. Frouzakis ◽  
P. F. Fischer ◽  
A. G. Tomboulides ◽  
K. Boulouchos
Keyword(s):  
Gas Exchange ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Exchange Process ◽  
Internal Combustion ◽  
High Order ◽  
Order Method ◽  
High Order Method ◽  
Gas Exchange Process

A Table of Thermodynamic Properties of Air

1943 ◽  
Vol 10 (3) ◽  
pp. A123-A130
Author(s):  
Joseph H. Keenan ◽  
Joseph Kaye
Keyword(s):  
Thermodynamic Properties ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Linear Interpolation ◽  
Combustion Engines ◽  
Dry Air ◽  
Single Argument ◽  
Air Compressors

Abstract Over the range of conditions for which the equation pv = RT represents satisfactorily the p-v-T relation, a table having a single argument, the temperature, serves all the purposes which are served by vapor tables (steam tables, ammonia tables, etc.) having two arguments. A table of this sort with intervals small enough for linear interpolation is presented for dry air. Data from this table are compared with corresponding values from the tables of Sage and Lacey. The use of the table is illustrated with examples of the calculation of processes involved in air compressors, nozzles, internal-combustion engines, and gas turbines.

scholarly journals Experimental test and thermodynamic analysis on scaling-down limitations of a reciprocating internal combustion engine

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093573
Author(s):  
Huichao Shang ◽  
Li Zhang ◽  
Bin Chen ◽  
Xi Chen
Keyword(s):  
Gas Exchange ◽  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Small Scale ◽  
Combustion Engines ◽  
Effective Pressure ◽  
Scaling Down ◽  
Meso Scale

Due to the enormous energy densities of liquid hydrocarbon fuels for future utilization on micro scale, there is a concern about the feasibility of scaling down reciprocating internal combustion engines from small scale to meso scale. By building a specialized test bench, the performance and combustion characteristics of a miniature internal combustion engine with a displacement of 0.99 cc were tested, and the thermodynamic simulation was carried out to achieve a more complete understanding of in-cylinder mass and energy change of the miniature internal combustion engine. The miniature internal combustion engine had higher brake-specific fuel consumption, lower thermal efficiency, lower brake mean effective pressure, and serious cyclic variation; however, friction mean effective pressure seems to be less sensitive to engine speed. Simulation results showed that the miniature internal combustion engine had a poor volumetric efficiency, which was not more than 50%. The step-by-step processes of scaling down the miniature internal combustion engine were also simulated; it was found that the maximum indicated mean effective pressure loss was due to the imperfection of gas exchange processes, and the next was the imperfection of combustion. It is considered that for the scaled-down miniature internal combustion engines, more attention should be pay on improving the processes of gas exchange and combustion, and achieving meso-scale internal combustion engines with cylinder bore less than 1 mm is thermodynamically possible in future if these imperfections, especially that of the gas exchange process, can be effectively perfected.

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