scholarly journals TDC Offset Estimation from Motored Cylinder Pressure Data based on Heat Release Shaping

Author(s):  
P. Tunestål
Author(s):  
Raj Kumar ◽  
Ming Zheng ◽  
Graham T. Reader

The multi-pulse fuel injection in a diesel engine is considered an effective way to reduce nitrogen oxides (NOx) emissions by heat-release shaping. In this research a preliminary energy efficiency analysis has been conducted for various split injection rates and schedules using the in-house and the commercial engine simulation software. Theoretical findings have been validated using experimentally obtained cylinder pressure data for various injection timings from a single-cylinder engine. The theoretical analysis on the shape of heat- release has been made to evaluate the energy efficiency of the post injection pulses on the engine exhaust temperature increases. An investigation of the cycle-to-cycle variation has also been performed for the measured cylinder pressure data.


Author(s):  
J. B. Weathers ◽  
B. T. Marvel ◽  
K. K. Srinivasan ◽  
P. J. Mago ◽  
L. M. Chamra ◽  
...  

Uncertainty within measured variables and how such errors propagate throughout a given equation or set of equations can greatly affect the accuracy and understanding of the result for a given experiment. The major motivation (or impetus) for performing a detailed uncertainty analysis before beginning an experiment is to identify variables or parameters that would have the greatest/least impact on the total uncertainty of the result. The scope of this study is to perform a detailed uncertainty analysis on estimates of net heat release in a compression ignition engine. The analysis will examine each term of the net heat release rate equation, which is routinely estimated using a single zone thermodynamic model, and evaluate the respective Uncertainty Magnification Factors (UMF) and Uncertainty Percentage Distribution (UPC). Since the net work output from the engine is directly related to in-cylinder pressure data, it is important to evaluate the uncertainties associated with cylinder pressure measurement. The primary objective of this paper is to analyze the effect of biased and precision uncertainties associated with the measured cylinder pressure data on the rate of heat release (ROHR) of a pilot ignited natural gas engine. Sensitivity analysis of other parameters such as the correct estimation of compression ratio and using appropriate thermodynamic properties of combustion gases are also discussed. The estimates from this analysis are expected to aid the development of a detailed experimental matrix to analyze the nature of energy release and performance of combustion engines.


2014 ◽  
Vol 984-985 ◽  
pp. 957-961
Author(s):  
Vijayashree ◽  
P. Tamil Porai ◽  
N.V. Mahalakshmi ◽  
V. Ganesan

This paper presents the modeling of in-cylinder pressure variation of a four-stroke single cylinder spark ignition engine. It uses instantaneous properties of working fluid, viz., gasoline to calculate heat release rates, needed to quantify combustion development. Cylinder pressure variation with respect to either volume or crank angle gives valuable information about the combustion process. The analysis of the pressure – volume or pressure-theta data of a engine cycle is a classical tool for engine studies. This paper aims at demonstrating the modeling of pressure variation as a function of crank angle as well as volume with the help of MATLAB program developed for this purpose. Towards this end, Woschni heat release model is used for the combustion process. The important parameter, viz., peak pressure for different compression ratios are used in the analysis. Predicted results are compared with experimental values obtained for a typical compression ratio of 8.3.


Author(s):  
Jianjun Zhu ◽  
Peng Li ◽  
Yufeng Xie ◽  
Xin Geng

The effects of compression ratio and fuel delivery advance angle on the combustion and emission characteristics of premixed methanol charge induced ignition by Fischer Tropsch diesel engine were investigated using a CY25TQ diesel engine. In the process of reducing the compression ratio from 16.9 to 15.4, the starting point of combustion is fluctuating, the peak of in-cylinder pressure and the maximum pressure increase rate decrease by 44.5% and 37.7% respectively. The peak instantaneous heat release rate increases by 54.4%. HC and CO emissions are on a rising trend. NOx and soot emissions were greatly decreased. The soot emission has the biggest drop of 50%. Reducing the fuel delivery advance angle will make the peak of in-cylinder pressure and the peak of pressure rise rate increase while the peak of heat release rate decreases. The soot emission is negatively correlated with the fuel delivery advance angle. When the fuel delivery advance angle is 16° CA, the soot emissions increased the most by 130%.


Author(s):  
Giulio Panzani ◽  
Olga Galluppi ◽  
Donald Selmanaj ◽  
Sergio Savaresi ◽  
Jonatan Rosgren ◽  
...  

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