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.

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

2015 ◽  
Author(s):  
Stephen Busch ◽  
Kan Zha ◽  
Alok Warey ◽  
Francesco Pesce ◽  
Richard Peterson
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Noise Reduction ◽  
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 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 heat-release 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 heat-release relative to those during main heat-release. 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% heat-release, peak heat-release 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 heat-release affect the combustion noise reduction mechanism, and maximum noise reduction is achieved when the height and steepness of the pilot heat-release profile are similar to the initial rise of the main heat-release event. A variation of the initial rise-rate of the main heat-release 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.

Noise-canceling spike between pilot and main-pressure-rise peaks of multiple-injection diesel combustion

2019 ◽  
Vol 20 (7) ◽  
pp. 788-804 ◽  
Author(s):  
Takayuki Fuyuto ◽  
Masahiro Taki
Keyword(s):  
Heat Release ◽  
Noise Reduction ◽  
Pressure Rise ◽  
Noise Spectrum ◽  
Frequency Component ◽  
Combustion Noise ◽  
Time Interval ◽  
Diesel Combustion ◽  
Main Injection ◽  
Noise Canceling

A previous study addressed combustion-noise reduction by optimizing the interval between two peaks in the pressure-rise rate (dP/dθ) of premixed charge combustion ignition with the split injection of fuel in diesel engines. Noise canceling occurs between two dP/dθ peaks, which reduces the overall combustion noise by lowering the maximum frequency component of the noise spectrum. The period of this frequency is twice the interval between the two dP/dθ peaks. We named this noise-reduction technique “noise-canceling spike” because it relies on the interference between a spike in the pressure rise and the preceding peak in the pressure rise. The time interval between the dP/dθ peaks must be controlled precisely to enable the utilization of the noise-canceling spike. In this article, the theory of the noise-canceling spike between the dP/dθ peak of the pilot injection and a single dP/dθ peak of the main injection is explained relatively simply, using experimental data analysis and zero-dimensional cycle simulations to prove that the noise-canceling spike is a universal phenomenon which occurs between the two dP/dθ peaks independently of the combustion (injection) strategy. Then, the theory of the noise-canceling spike is extended to those cases with three or more dP/dθ peaks, in which the noise-canceling spike can occur between every pair of dP/dθ peaks. Finally, we prove that the noise-canceling spike can occur between the dP/dθ peak of the pilot heat release and the multiple dP/dθ peaks of the main heat release in diesel combustion. The noise-canceling spike between the dP/dθ peak of the pilot combustion and the first dP/dθ peak of the main combustion becomes the dominating factor which reduces the overall combustion noise. In addition, the reasons why there have previously been no reports of the canceling and amplifying between the two dP/dθ peaks are discussed.

Combustion Noise Real-Time Evaluation and Processing for Combustion Control

2012 ◽  
Author(s):  
Fabrizio Ponti ◽  
Vittorio Ravaglioli ◽  
Davide Moro ◽  
Matteo De Cesare
Keyword(s):  
Diesel Engine ◽  
Closed Loop ◽  
Control Strategies ◽  
Combustion Process ◽  
Combustion Noise ◽  
Pollutant Emissions ◽  
Cylinder Pressure ◽  
Combustion Control ◽  
Engine Noise ◽  
Injection Parameters

Newly developed Diesel engine control strategies are mainly aimed at pollutant emissions reduction, due to the increasing request for engine-out emissions and fuel consumption reduction. In order to reduce engine-out emissions, the development of closed-loop combustion control algorithms has become crucial. Modern closed-loop combustion control strategies are characterized by two main aspects: the use of high EGR rates (the goal being to obtain highly premixed combustions) and the control of the center of combustion. In order to achieve the target center of combustion, conventional combustion control algorithms correct the measured value by varying Main injection timing. It is possible to obtain a further reduction in pollutant emissions through a proper variation of the injection parameters. Modern Diesel engine injection systems allow designing injection patterns with many degrees of freedom, due to the large number of tuneable injection parameters (such as start and duration of each injection). Each injection parameter’s variation causes variations in the whole combustion process and, consequently, in pollutant emissions production. Injection parameters variations have a strong influence on other quantities that are related to combustion process effectiveness, such as noise radiated by the engine. This work presents a methodology that allows real-time evaluating combustion noise on-board a vehicle. The radiated noise can be evaluated through a proper in-cylinder pressure signal processing. Even though in-cylinder pressure sensor on-board installation is still uncommon, it is believed that in-cylinder pressure measurements will be regularly available on-board thanks to the newly developed piezo-resistive sensors. In order to set-up the methodology, several experimental tests have been performed on a 1.3 liter Diesel engine mounted in a test cell. The engine was run, in each operating condition, both activating and deactivating pre-injections, since pre-injections omission usually produces a decrease in pollutant emissions production (especially in particulate matter) and a simultaneous increase in engine noise. The investigation of the correlation between combustion process and engine noise can be used to set up a closed-loop algorithm for optimal combustion control based on engine noise prediction.

Numerical and Experimental Study on the Impact of Mild Cold EGR on Exhaust Emissions in a Biodiesel Fueled Diesel Engine

2021 ◽  
Author(s):  
Alex Oliveira ◽  
Junfeng Yang ◽  
Jose Sodre
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Exhaust Emissions ◽  
Pollutant Emissions ◽  
Cylinder Pressure ◽  
Nox Formation ◽  
Ratio Distribution ◽  
Engine Model ◽  
Gas Recirculation ◽  
The Impact

Abstract This work evaluated the effect of cooled exhaust gas recirculation (EGR) on fuel consumption and pollutant emissions from a diesel engine fueled with B8 (a blend of biodiesel and Diesel 8:92%% by volume), experimentally and numerically. Experiments were carried out on a Diesel power generator with varying loads from 5 kW to 35 kW and 10% of cold EGR ratio. Exhaust emissions (e.g. THC, NOX, CO etc.) were measured and evaluated. The results showed mild EGR and low biodiesel content have minor impact of engine specific fuel consumption, fuel conversion efficiency and in-cylinder pressure. Meanwhile, the combination of EGR and biodiesel reduced THC and NOX up to 52% and 59%, which shows promising effect on overcoming the PM-NOX trade-off from diesel engine. A 3D CFD engine model incorporated with detailed biodiesel combustion kinetics and NOx formation kinetics was validated against measured in-cylinder pressure, temperature and engine-out NO emission from diesel engine. This valid model was then employed to investigate the in-cylinder temperature and equivalence ratio distribution that predominate NOx formation. The results showed that the reduction of NOx emission by EGR and biodiesel is obtained by a little reduction of the local in-cylinder temperature and, mainly, by creating comparatively rich combusting mixture.

Combustion Characteristics of Single Cylinder Diesel Engine Fueled with Blends of Thumba Biodiesel as an Alternative Fuel

2019 ◽  
Vol 969 ◽  
pp. 451-460
Author(s):  
Manpreet Singh ◽  
Mohd Yunus Sheikh ◽  
Dharmendra Singh ◽  
P. Nageswara Rao
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Heat Release Rate ◽  
Diesel Fuel ◽  
Release Rate ◽  
Mass Fraction ◽  
Pressure Rise ◽  
Cylinder Pressure ◽  
Gas Temperature ◽  
Edible Vegetable Oil

The rapid rise in energy requirement and problem regarding atmosphere pollutions, renewable biofuels are the better alternative choice for the internal combustion engine to partially or totally replace the pollutant petroleum fuel. In the present work, thumba (Citrullus colocynthis) non-edible vegetable oil is used for the production of biodiesel and examine its possibility as diesel engine fuel. Transesterification process is used to produce biodiesel from thumba non-edible vegetable oil. Thumba biodiesel (TBD) is used to prepare five different volume concentration (blends) with neat diesel (D100), such as TBD5, TBD15, TBD25, TBD35 and TBD45 to run a single cylinder diesel engine. The diesel engine's combustion parameter such as in-cylinder pressure, rate of pressure rise, net heat release rate, cumulative heat release, mean gas temperature, and mass fraction burnt analyzed through graphs and compared all thumba biodiesel blends result with neat diesel fuel. The mass fraction burnt start earlier for thumba biodiesel blends compared to diesel fuel because of less ignition delay while peak in-cylinder pressure, maximum rate of pressure rise, maximum net heat release rate, maximum cumulative heat release, and maximum mean gas temperature has found decreased results up to 1.93%, 5.53%, 4.11%, 4.65%, and 1.73% respectively for thumba biodiesel.

Study on the Combustion Noise Characteristic of Low Speed Diesel Engine

2014 ◽  
Vol 945-949 ◽  
pp. 750-753 ◽  
Author(s):  
Li Qi Yan ◽  
Hui Jun Ge
Keyword(s):  
Diesel Engine ◽  
Vibration Control ◽  
Combustion Engine ◽  
Combustion Noise ◽  
Aerodynamic Noise ◽  
Power Device ◽  
Response Analysis ◽  
Cylinder Pressure ◽  
Real Condition ◽  
Low Speed

In recent years, the Low speed two stroke diesel engines are widely used as the main power device of big ship for its so many advantages such as the high power, better economical efficiency and good maintenance. However, the problem of diesel strong vibration and noise becomes a more and more serious at the same time. Because of the Construction Features of marine two-stroke low-speed diesel engine, the structure has to be suffered different kind of forces when it runs. In considering the source of vibration, the whole noise can be divided into combustion noise、machinery noise and aerodynamic noise. The combustion noise caused by cylinder pressure is the most important part of diesel noise. In this paper, the cylinder pressure curves are tested. The internal combustion engine dynamics and the equivalent node load are used in the calculation procedure to achieve the real condition simulation. The loading program is made to simulate the change of cylinder pressure and the move of piston. The transient response of the diesel engine is calculated. The characteristics of diesel caused by cylinder pressure are analyzed.The response analysis can be used to the vibration control.

Experimental investigation of the combustion characteristics of a biodiesel (rice-bran oil methyl ester)-fuelled direct-injection transportation diesel engine

2007 ◽  
Vol 221 (8) ◽  
pp. 921-932 ◽  
Author(s):  
S Sinha ◽  
A K Agarwal
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Vegetable Oils ◽  
Rice Bran ◽  
Rice Bran Oil ◽  
Direct Injection ◽  
Pressure Rise ◽  
Cylinder Pressure ◽  
Biodiesel Blends ◽  
Crank Angle

Increased environmental awareness and depletion of fossil petroleum resources are driving industry to develop alternative fuels that are environmentally more acceptable. Transesterified vegetable oil derivatives called ‘biodiesel’ appear to be the most convenient way of utilizing bio-origin vegetable oils as substitute fuels in diesel engines. The methyl esters of vegetable oils do not require significant modification of existing engine hardware. Previous research has shown that biodiesel has comparable performance and lower brake specific fuel consumption than diesel with significant reduction in emissions of CO, hydrocarbons (HC), and smoke but slightly increased NO x emissions. In the present experimental research work, methyl ester of rice-bran oil is derived through transesterification of rice-bran oil using methanol in the presence of sodium hydroxide (NaOH) catalyst. Experimental investigations have been carried out to examine the combustion characteristics in a direct injection transportation diesel engine running with diesel, biodiesel (rice-bran oil methyl ester), and its blends with diesel. Engine tests were performed at different engine loads ranging from no load to rated (100 per cent) load at two different engine speeds (1400 and 1800 r/min). A careful analysis of the cylinder pressure rise, heat release, and other combustion parameters such as the cylinder peak combustion pressure, rate of pressure rise, crank angle at which peak pressure occurs, rate of pressure rise, and mass burning rates was carried out. All test fuels exhibited similar combustion stages as diesel; however, biodiesel blends showed an earlier start of combustion and lower heat release during premixed combustion phase at all engine load-speed combinations. The maximum cylinder pressure reduces as the fraction of biodiesel increases in the blend and, at higher engine loads, the crank angle position of the peak cylinder pressure for biodiesel blends shifted away from the top dead centre in comparison with baseline diesel data. The maximum rate of pressure rise was found to be higher for diesel at higher engine loads; however, combustion duration was higher for biodiesel blends.

Diesel Engine Combustion Sensing Methodology Based on Vibration Analysis

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Ponti Fabrizio ◽  
Ravaglioli Vittorio ◽  
Cavina Nicolò ◽  
De Cesare Matteo
Keyword(s):  
Diesel Engine ◽  
Closed Loop ◽  
Combustion Process ◽  
Pressure Sensors ◽  
Thermal Conditions ◽  
Pollutant Emissions ◽  
Accurate Estimation ◽  
Cylinder Pressure ◽  
Combustion Control ◽  
Real Time Analysis

The increasing request for pollutant emissions reduction spawned a great deal of research in the field of combustion control and monitoring. As a matter of fact, newly developed low temperature combustion strategies for diesel engines allow obtaining a significant reduction both in particulate matter and NOx emissions, combining the use of high EGR rates with a proper injection strategy. Unfortunately, due to their nature, these innovative combustion strategies are very sensitive to in-cylinder thermal conditions. Therefore, in order to obtain a stable combustion, a closed-loop combustion control methodology is needed. Many works demonstrate that a closed-loop combustion control strategy can be based on real-time analysis of in-cylinder pressure trace that provides important information about the combustion process, such as start of combustion, center of combustion and torque delivered by each cylinder. Nevertheless, cylinder pressure sensors on-board installation is still uncommon, due to problems related to unsatisfactory measurement long term reliability and cost. This paper presents a newly developed approach that allows extracting information about combustion effectiveness through the analysis of engine vibrations. In particular, the developed methodology can be used to obtain an accurate estimation of the indicated quantities of interest combining the information provided by engine speed fluctuations measurement and by the signals coming from acceleration transducers mounted on the engine. This paper also reports the results obtained applying the whole methodology to a light-duty turbocharged common rail diesel engine.

Sign in / Sign up

Export Citation Format

Share Document