Paper 21: An Experimental Investigation into Multi-Cylinder Turbocharged Two-Stroke Engine Exhaust Systems

1965 ◽  
Vol 180 (10) ◽  
pp. 290-300
Author(s):  
R. S. Benson ◽  
A. Wild
Keyword(s):  
Pulse Generator ◽  
Area Ratio ◽  
Maximum Efficiency ◽  
Exhaust Pipe ◽  
Test Results ◽  
Engine Exhaust ◽  
Pipe Length ◽  
Pipe System ◽  
Availability Factor ◽  
Basic Configuration

The results are given from a comprehensive investigation of the exhaust pipe configurations for five-, six-, seven-and eight-cylinder turbocharged two-stroke engines. The tests were carried out under cold conditions on a multi-cylinder pulse generator. For each engine two firing orders and the maximum number of alternative pipe arrangements compatible with minimum interference between cylinders were examined. Three nozzle sizes were tested for each basic configuration. The test results were analysed to determine the maximum efficiency of the exhaust pipe, expressed as the availability factor, the average scavenge ratio and the distribution of retained air between cylinders. Results of the investigation showed that in the multi-cylinder system the scavenge ratio increased with increase in nozzle area ratio, increase in the number of cylinders discharging into the pipe system, and with decrease in pipe length. The gas retained in the cylinders was found to increase with decrease in nozzle area to pipe area ratio and decrease in pipe volume. The availability factor was found to increase with decrease in nozzle area to pipe area ratio and decrease in pipe volume.

Paper 14: Discharge from a Cylinder through a Poppet Valve to an Exhaust Pipe

1967 ◽  
Vol 182 (8) ◽  
pp. 137-144 ◽  
Author(s):  
W. A. Woods ◽  
S. R. Khan
Keyword(s):  
Gas Exchange ◽  
Unsteady Flow ◽  
Pulse Generator ◽  
Pressure Ratio ◽  
Effective Area ◽  
Exhaust Pipe ◽  
Pipe System ◽  
Method Of Calculation ◽  
Poppet Valve ◽  
Exchange Processes

This paper is concerned with the gas exchange processes which occur in an engine. Previous work has been concerned with unsteady flow within the exhaust pipework; the present investigation provides a link between the cylinder and the pipe. The modifications to the pulse generator machine which was used to simulate an engine are described, and an account is given of the tests carried out with the machine. The previous steady flow tests are briefly summarized and the unsteady flow tests which were carried out are summarized with the aid of a table. The paper also presents a discussion of the test results and of calculations carried out to compare with the experiments. The main conclusion from the results is that a very satisfactory method has been devised for calculating the gas exchange processes occurring in an engine model. The main detailed conclusions are: (1) The dependence upon pressure ratio of the effective area of a poppet valve need not be taken into account for the analysis of unsteady flow tests. (2) Calculations on unsteady flow and gas exchange should be made on a theoretical model which has an exhaust pipe equal in length to the actual external exhaust pipe plus the length of the ‘exhaust bend’. (3) The method of calculation using the cylinder boundary conditions is an improvement on the previous type of calculations, which used a ‘pressure input’ as a boundary condition. Finally, the present work on a pulse generator with fixed piston using cold air, has provided a means of calculating the gas exchange processes from a knowledge of the release and supercharge pressures and the engine geometry. It has, therefore, provided an important link between the engine cylinder and the exhaust pipe system.

The Effect of the Exhaust Pipe Arrangement on Motorcycle Engine Acoustics

2006 ◽  
Author(s):  
Frank K. T. Lin
Keyword(s):  
Flow Rate ◽  
Engine Performance ◽  
Sound Level ◽  
Exhaust Pipe ◽  
Engine Exhaust ◽  
Pipe Length ◽  
Major Function ◽  
Exhaust Noise ◽  
Motorcycle Engine ◽  
Unequal Length

This paper uses a commercial CAE software GT-POWER to simulate the V-twin cylinder motorcycle engine exhaust acoustics. Ten different engine exhaust pipes with equal and unequal length and with or without arc connecting tube are designed. The engine performance and tailpipe exhaust noise on nineteen different engine speeds from 1000rpm to 10000rpm in wide-open throttle are studied. It is found that the effect of exhaust pipe configuration on the engine performance appears to be negligible. The tailpipe exhaust flow rate will be reduced and the overall sound level will bring down as the arc tube is connected to the exhaust front pipes. Also, the equal pipe length adapted with arc tube design gives a major function on pressure attenuation which may reduce the noise level significantly. The results may be useful for exhaust pipe design.

Exhaust-Pipe Effects in a Single-Cylinder Four-Stroke Engine

1940 ◽  
Vol 143 (1) ◽  
pp. 109-127 ◽  
Author(s):  
G. F. Mucklow
Keyword(s):  
Full Range ◽  
Exhaust Pipe ◽  
Valve Timing ◽  
Pipe Length ◽  
Exhaust Port ◽  
Single Cylinder ◽  
Wide Range ◽  
Different Diameters ◽  
Theoretical Considerations ◽  
Stroke Engine

The paper deals with an investigation of the fluctuations of pressure, due to piston motion on the exhaust stroke, which occur in the exhaust pipe of a single-cylinder four-stroke engine. Indicator diagrams of exhaust-port and of cylinder pressure, and measurements of air consumption were recorded, using exhaust pipes of three different diameters at three standard engine speeds; the exhaust pipe length was varied over a wide range in each case. In the light of the data thus obtained, the effects on air consumption of progressive alterations in valve timing were studied under known conditions of exhaust port pressure. Further trials were then carried out in which the valve timing which gave the maximum air consumption was determined for the full range of conditions of speed and exhaust pipe dimensions. The experimental results are discussed, and a method is derived by which the pressures in the exhaust port throughout the cycle may be obtained from theoretical considerations; the method is also directly applicable to induction pipe conditions.

Pulse Converters—A Method of Improving the Performance of the Turbocharged Diesel Engine

1973 ◽  
Vol 187 (1) ◽  
pp. 635-647 ◽  
Author(s):  
M. S. Janota ◽  
N. Watson
Keyword(s):  
Pulse Generator ◽  
Test Results ◽  
Turbocharged Diesel Engine ◽  
Turbine Efficiency ◽  
Different Types ◽  
Partial Admission ◽  
Characteristics Analysis ◽  
Pulse Converter ◽  
Flow Loss ◽  
Loss Coefficients

Today, most turbocharged diesel engines operate on the pulse system. This is most effective on those engines whose exhaust manifolds can connect groups of three cylinders to a turbine entry without scavenging interference, e.g. three-, six-, nine- and twelve-cylinder engines. However, when only two cylinders can be connected to each turbine entry, e.g. four-, eight- and sixteen-cylinder engines, without interference, the system is usually less efficient. This is because the widely fluctuating, partial admission turbine conditions lower the average turbine efficiency. Recently, the pulse converter has been developed to improve the performance of such engines. A detailed investigation into the operation and application of the pulse converter has been conducted. Test results from three completely different types of engines showed substantial improvements in performance. The dependence of the pulse converter on engine speed and load, the effect of area variations in the pulse converter and the timing of the interfering exhaust pressure waves have been studied. A comparison of theoretically predicted and measured transient pressures (from a model pulse converter fitted to a pulse generator) was made. The theoretical analysis is based on empirical steady-flow loss coefficients and forms a boundary condition for a method of characteristics analysis. Results are compared with those predicted by the simple constant-pressure theory.

Pressure Testing of New 8” Pipeline Lateral With Air

2006 ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
A. Glover ◽  
G. Nahas
Keyword(s):  
Air Temperature ◽  
Small Volume ◽  
Small Diameter ◽  
Area Ratio ◽  
Test Facility ◽  
Pilot Test ◽  
Test Results ◽  
Pressure Testing ◽  
Upper Limit ◽  
Simulated Test

A procedure for pressure testing of small diameter pipelines (up to NPS 12) using air has been developed based on pilot test results conducted on a controlled simulated test section of a small volume = 18.5 m3. This paper describes the simulated test facility and presents results of five simulated tests with different size pinhole leaks. A model describing leaks and effects of variation in air temperature has been developed, and together with the test results, a criteria for the upper limit of pipe volume to leak area ratio for implementation of air testing for various pipe sizes, has been arrived at. The procedure was then developed and utilized on a project approved by the Alberta Energy Utility Board. Results of this test on a new 12.2 km NPS 8 pipeline lateral in Alberta are also presented.

Overall and Stage Characteristics of Axial-flow Compressors

1950 ◽  
Vol 163 (1) ◽  
pp. 235-248 ◽  
Author(s):  
A. R. Howell ◽  
R. P. Bonham
Keyword(s):  
Axial Flow ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Test Results ◽  
Analytical Treatment ◽  
Axial Compressors ◽  
Simplified Method ◽  
Mass Flows ◽  
The Individual ◽  
Lengthy Process

Axial compressors, particularly near design conditions are, on the whole, amenable to analytical treatment, and usually a good estimate of their performance can be made before they are run. Away from the design points, the performances are conveniently thought of in terms of the overall characteristics of pressure-rises, temperature-rises, and efficiencies plotted against mass-flows. For these performance estimations the aerodynamicists must have knowledge of the stage and overall characteristics of previous compressors and of methods of predicting such characteristics. Obtaining the overall characteristics from a stage-by-stage calculation is a lengthy process, but, fortunately, simplified methods can often be used. In this lecture we have indicated some of the methods that are employed to obtain and predict the overall characteristics and their associated stage characteristics. Reference is made to test-results from various National Gas Turbine Establishment research compressors, one of which uses water instead of air as the working fluid, and also to published information on other compressors. The importance of blade and test errors on performance and analysis work is also emphasized. In our simplified method of analysis and prediction of overall characteristics we have reduced the individual overall characteristics at each speed to what are, in effect, mean stage characteristics plotted relative to their maximum-efficiency-point conditions. Then the maximum-efficiency-point conditions at the different speeds are plotted and considered separately.

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