Effect of design and operating parameters on the ion current in a single-cylinder diesel engine

Liu

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2014

An investigation was conducted of the ion current characteristics at various excess air ratios λ in a spark ignition engine fuelled with natural-gas–hydrogen blends. The Gaussian mathematical method was employed to fit the pure ion current signal without a spark tail generated by the ignition discharge. The cylinder pressure was recorded, and the Pauta criterion static threshold was used to deal with the outlier errors in the testing data for given cycles. The results show that the spark tail and the ion current can be separated by fitting the ion current with the Gaussian method, and the fitted pure ion current includes the flame-front stage and the post-flame stage. The timing with respect to the flame-front peak exhibits an irregular variation with λ. The maximum current in the flame-front stage increases with increasing λ.The timing of the maximum current in the post-flame stage occurs earlier at the stoichiometric ratio than at other air-to-fuel ratios. The correlation coefficient between the ion current in the post-flame stage and the pressure data treated with the Pauta criterion method increases. In addition, there are high correlation coefficients between the ion current and the pressure.

Section: Parameterization Of the Ion Current With Gaussian Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The correlation between the cylinder pressure and the ion current fitted with a Gaussian algorithm for a spark ignition engine fuelled with natural-gas–hydrogen blends

Liu

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2014

“…When the engine is running under EGR conditions, the ion current signal is weakened due to the decrease in combustion temperature, but the correlation between the ion current signal and the combustion parameters is still as high as 0.9 [38]. On the natural gas engines and diesel engines, it is also found that the correlation between ion current signal and combustion parameters is higher than 0.9 [39,40]. In addition, on the HCCI engine, the experimental results of Johansson et al [41] show that the correlation coefficient of the ion current characteristic parameter and CA50 is 0.877, so the ion current signal can be used to estimate the combustion phase of HCCI.…”

Section: Introductionmentioning

confidence: 98%

Development and Application of Ion Current/Cylinder Pressure Cooperative Combustion Diagnosis and Control System

et al. 2020

The application of advanced technologies for engine efficiency improvement and emissions reduction also increase the occurrence possibility of abnormal combustions such as incomplete combustion, misfire, knock or pre-ignition. Novel promising combustion modes, which are basically dominated by chemical reaction kinetics show a major difficulty in combustion control. The challenge in precise combustion control is hard to overcome by the traditional engine map-based control method because it cannot monitor the combustion state of each cycle, hence, real-time cycle-resolved in-cylinder combustion diagnosis and control are required. In the past, cylinder pressure and ion current sensors, as the two most commonly used sensors for in-cylinder combustion diagnosis and control, have enjoyed a seemingly competitive relationship, so all related researches only use one of the sensors. However, these two sensors have their own unique features. In this study, the idea is to combine the information obtained from both sensors. At first, two kinds of ion current detection system are comprehensively introduced and compared at the hardware level and signal level. The most promising variant (the DC-Power ion current detection system) is selected for the subsequent experiments. Then, the concept of ion current/cylinder pressure cooperative combustion diagnosis and control system is illustrated and implemented on the engine prototyping control unit. One application case of employing this system for homogenous charge compression ignition abnormal combustion control and its stability improvement is introduced. The results show that a combination of ion current and cylinder pressure signals can provide richer and also necessary information for combustion control. Finally, ion current and cylinder pressure signals are employed as inputs of artificial neural network (ANN) models for combustion prediction. The results show that the combustion prediction performance is better when the inputs are a combination of both signals, instead of using only one of them. This offline analysis proves the feasibility of using an ANN-based model whose inputs are a combination of ion current and pressure signals for better prediction accuracy.

“…Additionally, Yoshiyama et al 31 designed multiple ion sensors to obtain the ion current in an SI engine, and found that the peak location of the ion current is close to the peak location of heat release calculated from the measured cylinder pressure under all engine operating modes. Furthermore, Badawy et al 32 presented experimental data and analysis of the ion current produced in a single-cylinder diesel engine equipped with an electronically controlled common-rail-injection system using an accessible engine control unit, and the correlation coefficients between combustion parameters and the ion current were investigated. However, further research is still needed to find a more accurate parameter for the pressure characteristic correlation.…”

Section: Introductionmentioning

confidence: 99%

The interdependency between the maximal pressure and ion current in a spark-ignition engine

International Journal of Engine Research

Huang

et al. 2012

An experimental investigation on the interdependency between the maximal pressure and ion current in a spark-ignition engine was conducted in this work. Eight ion current sensors were located centrally symmetric in a gasket between the cylinder and its head. The measurements of the ion current and the start timing, peak timing and end timing of the ion current were compared and the optimized interdependency between the maximal pressure and characteristic parameter of ion current was investigated. Experimental results show that the peak timing and the end timing of the ion current depend strongly on the start timing of the ion current for each ion sensor. The interdependency between the maximal pressure and start timing detected from the sensors near the intake port is better than that of the exhaust port. Furthermore, interdependency between the maximal pressure and average start timing from sensors 3 to 7 were found to give the best performance regardless the engine test conditions. The maximum pressure and average start timings were found to vary inversely with increasing intake pressure, ignition timing and excess air fuel ratio.