scholarly journals Prediction of Noise Levels Generated by an Engine Exhaust : 1st Report, Preliminary Study on a Single-Cylinder Engine with a Straight Exhaust Pipe at Motoring

1978 ◽  
Vol 44 (377) ◽  
pp. 250-259 ◽  
Author(s):  
Kazuie NISHIWAKI ◽  
Yuzuru SHIMAMOTO
1998 ◽  
Vol 122 (4) ◽  
pp. 533-540 ◽  
Author(s):  
M. Vandevoorde ◽  
R. Sierens ◽  
E. Dick

Recently a new TVD scheme was presented by the authors and a comparison was made with other algorithms for two engine related test cases (the shock tube and the tapered pipe). It was shown that the new scheme combines high accuracy with exact conservation of the mass flow, even in tapered pipes. In this paper the pressure waves in the inlet and exhaust system of a single cylinder engine are measured and compared to calculations with the new algorithm. The comparison is made under motoring and firing conditions of the engine with two different external mixture formation systems (different fuels: gasoline and methane). Modifications on intake and exhaust pipe configuration clearly show their influence on the pressure wave development. The importance of the loss coefficients for the flow through the inlet and exhaust valves (mass flow coefficient) is demonstrated. A test rig has been built to obtain these coefficients under steady-state conditions as a function of valve lift and mass flow rate. It is shown that for this engine configuration the measured steady-state loss coefficients are not reliable at low valve lifts. This can be explained by the influence of the Reynolds number and the appearance of a transition zone. For all mentioned comparisons the agreement is excellent. The next phase will be to evaluate the code for multi-cylinder engines under atmospheric and turbo-charged conditions. [S0742-4795(00)00204-0]


Author(s):  
John L. Lahti ◽  
Matthew W. Snyder ◽  
John J. Moskwa

A transient test system was developed for a single cylinder research engine that greatly improves test accuracy by allowing the single cylinder to operate as though it were part of a multi-cylinder engine. The system contains two unique test components: a high bandwidth transient hydrostatic dynamometer, and an intake airflow simulator. The high bandwidth dynamometer is used to produce a speed trajectory for the single cylinder engine that is equivalent to that produced by a multi-cylinder engine. The dynamometer has high torque capacity and low inertia allowing it to simulate the speed ripple of a multi-cylinder engine while the single cylinder engine is firing. Hardware in loop models of the drivetrain and other components can be used to test the engine as though it were part of a complete vehicle, allowing standardized emissions tests to be run. The intake airflow simulator is a specialized intake manifold that uses solenoid air valves and a vacuum pump to draw air from the manifold plenum in a manner that simulates flow to other engine cylinders, which are not present in the single cylinder test configuration. By regulating this flow from the intake manifold, the pressure in the manifold and the flow through the induction system are nearly identical to that of the multi-cylinder application. The intake airflow simulator allows the intake runner wave dynamics to be more representative of the intended multi-cylinder application because the appropriate pressure trajectory is maintained in the intake manifold plenum throughout the engine cycle. The system is ideally suited for engine control development because an actual engine cylinder is used along with a test system capable of generating a wide range of transient test conditions. The ability to perform transient tests with a single cylinder engine may open up new areas of research exploring combustion and flow under transient conditions. The system can also be used for testing the engine under conditions such as cylinder deactivation, fuel cut-off, and engine restart. The improved rotational dynamics and improved intake manifold dynamics of the test system allow the single cylinder engine to be used for control development and emissions testing early in the engine development process. This can reduce development time and cost because it allows hardware problems to be identified before building more expensive multi-cylinder engines.


2004 ◽  
Author(s):  
Michael McMillian ◽  
Steven Richardson ◽  
Steven D. Woodruff ◽  
Dustin McIntyre

1940 ◽  
Vol 143 (1) ◽  
pp. 109-127 ◽  
Author(s):  
G. F. Mucklow

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.


2021 ◽  
pp. 1-39
Author(s):  
Akash Chandrabhan Chandekar ◽  
Sushmita Deka ◽  
Biplab K. Debnath ◽  
Ramesh Babu Pallekonda

Abstract The persistent efforts among the researchers are being done to reduce emissions by the exploration of different alternative fuels. The application of alternative fuel is also found to influence engine vibration. The present study explores the potential connection between the change of the engine operating parameters and the engine vibration pattern. The objective is to analyse the effect of alternative fuel on engine vibration and performance. The experiments are performed on two different engines of single cylinder and twin-cylinder variants at the load range of 0 to 34Nm, with steps of 6.8Nm and at the constant speed of 1500rpm. The single cylinder engine, fuelled with only diesel mode, is tested at two compression ratios of 16.5 and 17.5. While, the twin-cylinder engine with a constant compression ratio of 16.5, is tested at both diesel unifuel and diesel-compressed natural gas dual-fuel modes. Further, in dual-fuel mode, tests are conducted with compressed natural gas substitutions of 40%, 60% and 80% for given loads and speed. The engine vibration signatures are measured in terms of root mean square acceleration, representing the amplitude of vibration. The combustion parameters considered are cylinder pressure, rate of pressure rise, heat release rate and ignition delay. At higher loads, the vibration amplitude increases along with the cylinder pressure. The maximum peak cylinder pressure of 95bar is found in the case of the single cylinder engine at the highest load condition that also produced a peak vibration of 3219m/s2.


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