Experimental Study on In-Cylinder Pressure Oscillations of Homogenous Charge Compression Ignition–Direct Injection Combustion Engine Fueled With Dimethyl Ether

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Junxing Hou ◽  
Jianwei Liu ◽  
Yongqiang Wei ◽  
Zhiqiang Jiang

The in-cylinder pressure oscillations of a homogeneous charge compression ignition (HCCI)-DI engine fueled with dimethyl ether (DME) have been investigated using discrete wavelet transform (DWT) based on four different wavelet functions. The in-cylinder pressure is decomposed into three levels that contain three details D1, D2, and D3, and an approximation A1. In normal combustion, there are no obvious pressure impacts in three details due to smooth combustion process. The abnormal pressure oscillations occur in three details in knocking combustion, and the oscillation is most intense in D1. Its frequency band 5–10 kHz is the knock frequency band, and most high-frequency pressure oscillations and wavelet energy are in this frequency band. The pressure oscillations are located in the premixed combustion stage and diffusion combustion stage. Characteristics of in-cylinder pressure oscillations can be extracted using four wavelet functions “db4,” “db8,” “sym4,” and “sym8.” Extract abilities of four wavelet functions are different and wavelet db4 is suitable for pressure oscillation detection.

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Junxing Hou ◽  
Zhenhua Wen ◽  
Jianwei Liu ◽  
Zhiqiang Jiang

A two-cylinder diesel engine was modified for a dimethyl ether (DME) homogeneous charge compression ignition (HCCI)-direct injection (DI) engine. Knock characteristics are investigated based on in-cylinder pressure signals. The in-cylinder pressure is decomposed into four levels using discrete wavelet transform (DWT). The maximum pressure amplitudes and wavelet energy at four levels are approximately equal in normal combustion. With knock, both the maximum pressure amplitude and wavelet energy at the third level are the greatest. The correlation analysis shows that the correlation coefficients for maximum pressure amplitude and wavelet energy are quite valid for the second and third levels. It indicates that the correlation is stronger at frequencies which belong to resonant frequencies. The wavelet energy has slightly better performance than maximum pressure amplitude for identification of knock.


2014 ◽  
Vol 607 ◽  
pp. 629-632
Author(s):  
Yan Yan ◽  
Yu Sheng Zhang

Taking into account China's abundant coal resources, methanol and DME(Dimethyl Ether) obtained from coal are good alternative fuels. The research project is to utilize the fuel of DME and methanol in diesel engines for new combustion models PCCI (Premixed Charge Compression Ignition).The tests of the PCCI mode with different boundary conditions were studied on PCCI test bench. PCCI combustion is consisted of three stages: low temperature reaction of DME, high-temperature reaction of DME and diffusion combustion reaction of methanol. DME as combustion improver should be kept relatively low concentration, and with the decrease of methanol, its concentration need to be reduced. Methanol and formaldehyde are important parts of HC emission, their volume fraction was about 70%.


Author(s):  
Jaekeun Park ◽  
Jaeou Chae

Abstract In-cylinder pressure of an internal combustion engine is considered to be a major source of information about combustion process. It is a generally accepted method to obtain an in-cylinder pressure signal using a pressure sensor (transducer). A different method of approach is presented in this study. The information about the in-cylinder pressure can be obtained by measuring breakdown voltage across the spark-plug gap. The density of gas inside the combustion chamber effect on the breakdown voltage of the spark plug, which is derived by the application of a high bias voltage (30kV) to the sparkplug gap continuously. The correlation between maximum breakdown voltage position and peak pressure position is established by this principle. So it is possible to detect the peak pressure position by measuring the breakdown voltage of the spark plug. The analyzing method of the breakdown voltage signal is also presented.


2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Xiao Huang ◽  
Lulu Kang ◽  
Mateos Kassa ◽  
Carrie Hall

In-cylinder pressure is a critical metric that is used to characterize the combustion process of engines. While this variable is measured on many laboratory test beds, in-cylinder pressure transducers are not common on production engines. As such, accurate methods of predicting the cylinder pressure have been developed both for modeling and control efforts. This work examines a cylinder-specific pressure model for a dual fuel compression ignition engine. This model links the key engine input variables to the critical engine outputs including indicated mean effective pressure (IMEP) and peak pressure. To identify the specific impact of each operating parameter on the pressure trace, a surrogate model was produced based on a functional Gaussian process (GP) regression approach. The pressure trace is modeled as a function of the operating parameters, and a two-stage estimation procedure is introduced to overcome various computational challenges. This modeling method is compared to a commercial dual fuel combustion model and shown to be more accurate and less computationally intensive.


2014 ◽  
Vol 644-650 ◽  
pp. 394-397
Author(s):  
Yan Shi ◽  
Yong Feng Liu ◽  
Xiao She Jia

In order to simulate the combustion system work process for an internal combustion engine accurately,the paper simulates the combustion process which based on the modified 4JB1 engine and used the KIVA-3V software. Variables such as cylinder pressure, cylinder temperature, NOX and SOOT emission are predicted and analyzed by using single injection strategy.It was found that the production of NOX begins from the moderate burning period, reaches a peak quickly and keep constant. The production of SOOT is mainly in the late of fast burning period to the moderate burning period and most of the SOOT is oxidized.


2014 ◽  
Vol 543-547 ◽  
pp. 425-428
Author(s):  
Jian Ying Dai ◽  
Dong Ling Xiao

In the paper firstly analyzes the engine combustion theory, for the numerical analysis for engine cylinder pressure to provide the basis. This paper makes use of the FIRE simulation software to analyze the shrinkage mouth combustion engine under different working condition of the fuel injection advance Angle of the characteristics of the combustion process and exhaust process, after got the mixture combustion in cylinder gas pressure range and emissions, for the next step muffler simulation model is established by applying the method of finite element and acoustical noise analysis provides the basis of the parameters, shorten product development cycle.


2005 ◽  
Vol 128 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Mingfa Yao ◽  
Zunqing Zheng ◽  
Jin Qin

The homogeneous charge compression ignition (HCCI) combustion fueled by dimethyl ether (DME) and compressed natural gas (CNG) was investigated. The experimental work was carried out on a single-cylinder diesel engine. The results show that adjusting the proportions of DME and CNG is an effective technique for controlling HCCI combustion and extending the HCCI operating range. The combustion process of HCCI with dual fuel is characterized by a distinctive two-stage heat release process. As CNG flow rate increases, the magnitude of peak cylinder pressure and the peak heat release rate in the second stage goes up. As DME flow rate increases, the peak cylinder pressure, heat release rate, and NOx emissions increase while THC and CO emissions decrease.


Author(s):  
Ingemar Andersson ◽  
Lars Eriksson

A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that, after calibration, it has only two free parameters: burn angle and initial kernel temperature. By fitting the model to a measured ionization signal, it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data were collected on a Saab four-cylinder spark ignited engine for a variation in ignition timing and air-fuel ratio. The main result is that the parametrized ionization current model can be used to estimating combustion properties as pressure, temperature, and content of nitric oxides based on measured ionization currents. The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure. This ionization current model not only describes the connection between the ionization current and the combustion process, but also offers new possibilities for engine management system to control the internal combustion engine.


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