scholarly journals Development of the combustion noise index and control algorithm through signal processing of in-cylinder pressure for a diesel engine

2016 ◽  
Vol 35 (3) ◽  
pp. 208-215
Author(s):  
Jaemin Jin ◽  
Dongchul Lee ◽  
Insoo Jung
Keyword(s):  
Signal Processing ◽  
Diesel Engine ◽  
Control Algorithm ◽  
Combustion Noise ◽  
Cylinder Pressure ◽  
Noise Index ◽  
And Control

A Signal Processing of In-Cylinder Pressure for the Resonant Frequency Prediction of Combustion Process in Diesel Engines

2018 ◽  
Author(s):  
Ximing Chen ◽  
Long Liu ◽  
Jiguang Zhang ◽  
Jingtao Du
Keyword(s):  
Signal Processing ◽  
Fourier Transform ◽  
Wavelet Transform ◽  
Resonant Frequency ◽  
Diesel Engines ◽  
Combustion Process ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Empirical Wavelet Transform

The combustion resonance is a focal point of the analysis of combustion and thermodynamic processes in diesel engines, such as detecting ‘knock’ and predicting combustion noise. Combustion resonant frequency is also significant for the estimation of in-cylinder bulk gas temperature and trapped mass. Normally, the resonant frequency information is contained in in-cylinder pressure signals. Therefore, the in-cylinder pressure signal processing is used for resonant frequency calculation. Conventional spectral analyses, such as FFT (Fast Fourier transform), are unsuitable for processing in-cylinder pressure signals because of its non-stationary characteristic. Other approaches to deal with non-stationary signals are Short-Time Fourier Transform (STFT) and Continue Wavelet Transform (CWT). However, the choice of size and shape of window for STFT and the selection of wavelet basis for CWT are totally empirical, which is the limit for precisely calculating the resonant frequency. In this study, an approach based on Empirical Wavelet Transform (EWT) and Hilbert Transform (HT) is proposed to process in-cylinder pressure signals and extract resonant frequencies. In order to decompose in-cylinder pressure spectrum precisely, the EWT are applied for separating the frequency band corresponding combustion resonance mode from other irrelevant modes adaptively. The signals containing combustion resonant mode is processed by HT, so that the instantaneous resonant frequency and amplitude can be extracted. Validation is performed by four in-cylinder pressure signals with different injection timing. And the effects of injection timing on resonant frequency are discussed.

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.

Effect of Injection Parameters and Strategy on the Noise From a Single Cylinder Direct Injection Diesel Engine

2011 ◽  
Author(s):  
Sukhbir Singh Khaira ◽  
Amandeep Singh ◽  
Marcis Jansons
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Frequency Spectra ◽  
Single Cylinder ◽  
Direct Injection Diesel Engine ◽  
Injection Parameters

Acoustic noise emitted by a diesel engine generally exceeds that produced by its spark-ignited equivalent and may hinder the acceptance of this more efficient engine type in the passenger car market (1). This work characterizes the combustion noise from a single-cylinder direct-injection diesel engine and examines the degree to which it may be minimized by optimal choice of injection parameters. The relative contribution of motoring, combustion and resonance components to overall engine noise are determined by decomposition of in-cylinder pressure traces over a range of load, injection pressure and start of injection. The frequency spectra of microphone signals recorded external to the engine are correlated with those of in-cylinder pressure traces. Short Time Fourier Transformation (STFT) is applied to cylinder pressure traces to reveal the occurrence of motoring, combustion noise and resonance in the frequency domain over the course of the engine cycle. Loudness is found to increase with enhanced resonance, in proportion to the rate of cylinder pressure rise and under conditions of high injection pressure, load and advanced injection timing.

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.

A Model-Based Methodology for Real-Time Estimation of Diesel Engine Cylinder Pressure

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Ahmed Al-Durra ◽  
Marcello Canova ◽  
Stephen Yurkovich
Keyword(s):  
Signal Processing ◽  
Diesel Engine ◽  
Real Time ◽  
Closed Loop ◽  
Operating Conditions ◽  
Recursive Least Squares ◽  
Cylinder Pressure ◽  
Combustion Control ◽  
Model Based ◽  
Crank Angle

Cylinder pressure is one of the most important parameters characterizing the combustion process in an internal combustion engine. The recent developments in engine control technologies suggest the use of cylinder pressure as a feedback signal for closed-loop combustion control. However, the sensors measuring in-cylinder pressure are typically subject to noise and offset issues, requiring signal processing methods to be applied to obtain a sufficiently accurate pressure trace. The signal conditioning implies a considerable computational burden, which ultimately limits the use of cylinder pressure sensing to laboratory testing, where the signal can be processed off-line. In order to enable closed-loop combustion control through cylinder pressure feedback, a real-time algorithm that extracts the pressure signal from the in-cylinder sensor is proposed in this study. The algorithm is based on a crank-angle based engine combustion of that predicts the in-cylinder pressure from the definition of a burn rate function. The model is then adapted to model-based estimation by applying an extended Kalman filter in conjunction with a recursive least-squares estimation scheme. The estimator is tested on a high-fidelity diesel engine simulator as well as on experimental data obtained at various operating conditions. The results obtained show the effectiveness of the estimator in reconstructing the cylinder pressure on a crank-angle basis and in rejecting measurement noise and modeling errors. Furthermore, a comparative study with a conventional signal processing method shows the advantage of using the derived estimator, especially in the presence of high signal noise (as frequently happens with low-cost sensors).

scholarly journals Robotic Walker for Slope Mobility Assistance with Active-Passive Hybrid Actuator

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Junqiang Li ◽  
Lei Zhao ◽  
Tiejun Li
Keyword(s):  
Mechanical Properties ◽  
Signal Processing ◽  
Control Algorithm ◽  
Control Method ◽  
Dc Motor ◽  
Real Time Control ◽  
Time Control ◽  
Robotic Walker ◽  
And Control ◽  
Hybrid Actuator

AbstractWalking assistance can be realized by active and passive robotic walkers when their users walk on even roads. However, fast signal processing and real-time control are necessary for active robotic walkers when the users walk on slopes, while assistive forces cannot be provided by passive robotic walkers when the users walk uphill. A robotic walker with an active-passive hybrid actuator (APHA) was developed in this study. The APHA, which consists of a rotary magnetorheological (MR) brake and a DC motor, can provide mobility assistance to users walking both uphill and downhill via the cooperative operation of the MR brake and DC motor. The rotary MR brake was designed with a T-shaped configuration, and the system was optimized to minimize the brake volume. Prototypes of the APHA and robotic walker were constructed. A control algorithm for the robotic walker was developed based on the characteristics of the APHA and the structure of the robotic walker. The mechanical properties of the APHA were characterized, and experiments were conducted to evaluate the mobility assistance supplied by the robotic walker on different roads. The results show that the APHA can meet the requirements of the robotic walker, and suitable assistive forces can be provided by the robotic walker, which has a simple mechanical structure and control method.

scholarly journals A Comparative Assessment of Operating Characteristics of a Diesel Engine Using 20% Proportion of Different Biodiesel Diesel Blend

2019 ◽  
Vol 26 (1) ◽  
pp. 127-140
Author(s):  
Senthil Ramalingam ◽  
Silambarasan Rajendran ◽  
Pranesh Ganesan
Keyword(s):  
Diesel Engine ◽  
Corn Oil ◽  
Cylinder Pressure ◽  
Waste Oil ◽  
Operating Characteristics ◽  
Brake Thermal Efficiency ◽  
Compression Ignition Engines ◽  
Peak Cylinder Pressure ◽  
Biodiesel Blend ◽  
And Control

Abstract The objective of the present work is to find out the viable substitute fuel for diesel and control of pollutants from compression ignition engines. Therefore, in this present investigation an attempt has been made to study the effect of 20% proportion of five different biodiesel diesel blend in diesel engine. The 20% proportion of biodiesel such as Jatropha, Pongamia, Mahua, Annona and Nerium and 80% of diesel and it is denoted as J20, P20, M20, A20 and N20 are used in the present investigation. The experimental results showed that the brake thermal efficiency of the different biodiesel blend is slightly lower when compared to neat diesel fuel. However, N20 blend, have shown improvement in performance and reduction in exhaust emissions than that of other biodiesel diesel blends. From, the experimental work, it is found that biodiesel can be used up to 20% and 80% of diesel engine without any major modification. The conducted experiments were conducted on a four cylinder four stroke DI and turbo charged diesel engine using biodiesel blends of waste oil, rapeseed oil, and corn oil with normal diesel. The peak cylinder pressure of the engine running with bio diesel was slightly higher than that of diesel. The experiments were conducted on a four cylinder four stroke diesel engine using bio diesel made from corn oil.

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.

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