Experimental Analysis of Combustion Noise Reduction with Performance Optimization in 110cc CVT Scooter Engine

2016 ◽  
Author(s):  
Arun Prasath G ◽  
Saravanan Duraiarasan ◽  
R Govindarajan
Keyword(s):  
Noise Reduction ◽  
Experimental Analysis ◽  
Performance Optimization ◽  
Combustion Noise

On the Reduction of Combustion Noise by a Close-Coupled Pilot Injection in a Small-Bore Direct-Injection Diesel Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Stephen Busch ◽  
Kan Zha ◽  
Alok Warey ◽  
Francesco Pesce ◽  
Richard Peterson
Keyword(s):  
Diesel Engine ◽  
Noise Reduction ◽  
Pressure Rise ◽  
Combustion Noise ◽  
Pollutant Emissions ◽  
Destructive Interference ◽  
Cylinder Pressure ◽  
Reduction Mechanism ◽  
Initial Rise ◽  
Main Injection

For a pilot–main injection strategy in a single-cylinder light-duty diesel engine, the dwell between the pilot- and main-injection events can significantly impact combustion noise. As the solenoid energizing dwell decreases below 200 μs, combustion noise decreases by approximately 3 dB and then increases again at shorter dwells. A zero-dimensional thermodynamic model has been developed to capture the combustion noise reduction mechanism; heat release (HR) profiles are the primary simulation input and approximating them as top-hat shapes preserves the noise reduction effect. A decomposition of the terms of the underlying thermodynamic equation reveals that the direct influence of HR on the temporal variation of cylinder pressure is primarily responsible for the trend in combustion noise. Fourier analyses reveal the mechanism responsible for the reduction in combustion noise as a destructive interference in the frequency range between approximately 1 kHz and 3 kHz. This interference is dependent on the timing of increases in cylinder pressure during pilot HR relative to those during main HR. The mechanism by which combustion noise is attenuated is fundamentally different from the traditional noise reduction that occurs with the use of long-dwell pilot injections, for which noise is reduced primarily by shortening the ignition delay of the main injection. Band-pass filtering of measured cylinder pressure traces provides evidence of this noise reduction mechanism in the real engine. When this close-coupled pilot noise reduction mechanism is active, metrics derived from cylinder pressure such as the location of 50% HR, peak HR rates, and peak rates of pressure rise cannot be used reliably to predict trends in combustion noise. The quantity and peak value of the pilot HR affect the combustion noise reduction mechanism, and maximum noise reduction is achieved when the height and steepness of the pilot HR profile are similar to the initial rise of the main HR event. A variation of the initial rise rate of the main HR event reveals trends in combustion noise that are the opposite of what would happen in the absence of a close-coupled pilot. The noise reduction mechanism shown in this work may be a powerful tool to improve the tradeoffs among fuel efficiency, pollutant emissions, and combustion noise.

Simulation and Experimental Analysis for Noise Reduction of a Scooter Gearbox

2018 ◽  
Vol 35 (8) ◽  
pp. 777-782 ◽  
Author(s):  
Qi Zhang ◽  
Jing Zhang ◽  
Zhong Hua Liu ◽  
Jian Hua Lv ◽  
Zhen Qin ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Experimental Analysis

scholarly journals Optimization of multiple heat releases in pre-mixed diesel engine combustion for high thermal efficiency and low combustion noise by a genetic-based algorithm method

2018 ◽  
Vol 20 (5) ◽  
pp. 540-554 ◽  
Author(s):  
Gen Shibata ◽  
Hideyuki Ogawa ◽  
Yasumasa Amanuma ◽  
Yuki Okamoto
Keyword(s):  
High Temperature ◽  
Diesel Engine ◽  
Heat Release ◽  
Noise Reduction ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Combustion Noise ◽  
Two Stage ◽  
Temperature Heat ◽  
Optimum Heat

The reduction of diesel combustion noise by multiple fuel injections maintaining high indicated thermal efficiency is an object of the research reported in this article. There are two aspects of multiple fuel injection effects on combustion noise reduction. One is the reduction of the maximum rate of pressure rise in each combustion, and the other is the noise reduction effects by the noise canceling spike combustion. The engine employed in the simulations and experiments is a supercharged, single-cylinder direct-injection diesel engine, with a high pressure common rail fuel injection system. Simulations to calculate the combustion noise and indicated thermal efficiency from the approximated heat release by Wiebe functions were developed. In two-stage high temperature heat release combustion, the combustion noise can be reduced; however, the combustion noise in amplification frequencies must be reduced to achieve further combustion noise reduction, and an additional heat release was added ahead of the two-stage high temperature heat release combustion in Test 1. The simulations of the resulting three-stage high temperature heat release combustion were conducted by changing the heating value of the first heat release. In Test 2 where the optimum heat release shape for low combustion noise and high indicated thermal efficiency was investigated and the role of each of the heat releases in the three-stage high temperature heat release combustion was discussed. In Test 3, a genetic-based algorithm method was introduced to avoid the time-consuming loss and great care in preparing the calculations in Test 2, and the optimum heat release shape and frequency characteristics for combustion noise by the genetic-based algorithm method were speedily calculated. The heat release occurs after the top dead center, and the indicated thermal efficiency and overall combustion noise were 50.5% and 86.4 dBA, respectively. Furthermore, the optimum number of fuel injections and heat release shape of multiple fuel injections to achieve lower combustion noise while maintaining the higher indicated thermal efficiency were calculated in Test 4. The results suggest that the constant pressure combustion after the top dead center by multiple fuel injections is the better way to lower combustion noise; however, the excess fuel injected leads to a lower indicated thermal efficiency because the degree of constant volume becomes deteriorates.

Combustion Noise Measurement System for Low Emissions Combustor Performance Optimization and Health Monitoring

2003 ◽  
Author(s):  
Peter J. Stuttaford ◽  
Vince Martling ◽  
Andrew Green ◽  
Timothy C. Lieuwen
Keyword(s):  
Data Acquisition ◽  
Health Monitoring ◽  
Performance Optimization ◽  
Data Acquisition System ◽  
Combustion Noise ◽  
Acquisition System ◽  
Dynamic Monitoring ◽  
Dynamic Data ◽  
Base Load ◽  
Dynamic Data Acquisition

The design of modern gas turbine combustors continues to be driven by the demand for lower emissions of NOx and CO. Achieving reduced emissions on dry low emissions combustors necessitates the monitoring of associated, potentially destructive combustion noise. Power Systems Manufacturing (PSM) has developed a Dynamic Data Acquisition System for use in the noise performance optimization and health monitoring of low emissions combustors. Various noise probes and set-ups have been evaluated on test benches, combustion test rigs, and engines operating over their complete load range. The set-up and calibration of the combustion dynamic monitoring system is described here. An application of the dynamic data acquisition system is presented for the PSM combustor retrofit of the 85MW General Electric Frame MS7001EA machine, achieving 6ppm NOx, and 2ppm CO at base load and maintaining single digit emissions down to 50% load. The excellent condition of the combustion hardware following 8,000 hours of base load operation was indicative of operation in a low combustion noise environment. Combustion system noise monitoring ensures the lowest possible emissions, without compromising combustion hardware durability through excessive dynamic loading.

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