scholarly journals Repeatability of High-Pressure Measurement in a Diesel Engine Test Bed

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3478 ◽  
Author(s):  
Tomasz Skrzek ◽  
Mirosław Rucki ◽  
Krzysztof Górski ◽  
Jonas Matijošius ◽  
Dalibor Barta ◽  
...  

This paper addresses the issue of metrological accuracy of instantaneous in-cylinder pressure measurement in a diesel engine test bed. In studies, the central unit has been the single-cylinder AVL 5402 engine. The pressure measurement was performed with a sensor designed for thermodynamic analysis, and the results were related to the crank angle, where two rotations corresponding to the four-stroke working cycle were denoted as angles between −360° and +360°. The novelty of this paper is the proposition of how to perform a type A uncertainty estimation of the in-cylinder pressure measurement and to assess its repeatability. It was demonstrated that repeatability of the measurement during the ignition process was difficult to estimate because of the phenomena that cannot ensure the repeatability conditions. To solve the problem, two methods were proposed. In one method, the pressure was measured in the subsequent cycles immediately after the ignition was turned off, and in another method, the engine was driven by a starter. The latter method provided maximal pressure values much lower than during usual tests. The obtained repeatability of measured pressure was %EV = 0.4%, which proved high capability of the evaluated measurement system.

Author(s):  
Tomazˇ Katrasˇnik ◽  
Samuel Rodman Opresˇnik ◽  
Ferdinand Trenc ◽  
Nedjeljko Sˇkific´

A new criterion for the determination of the start of combustion (SOC) from the diesel engine in-cylinder pressure diagram was developed. It is defined as the maximum of the third order derivative of the cylinder pressure with respect the crank angle. This criterion declares SOC more precisely than other previously published criterions based on pressure diagnostics. This fact was proven analytically and was discernable from the analysis of the experimental data. Beside its accuracy it is also robust enough to allow automatic evaluation of the SOC during processing of the pressure data for a large number of cycles. Analysis of the first law of thermodynamics applied to the engine cylinder showed that the third order derivative of the cylinder pressure with respect to the crank angle is the most suitable criterion for determination of the SOC from the cylinder pressure diagram. Subsequently the criterion was validated through experimental data analysis of the cylinder pressure diagrams for various engine speeds and loads. Cylinder pressure diagrams were processed with a computer code based on the first law of thermodynamics to evaluate the rate of heat release (ROHR), which formed the base for experimental validation. The cylinder pressure was measured with an advanced piezoelectric sensor at the resolution 0.1 deg. CA. Top dead center was determined with the capacitive top dead center sensor. Due to the analytic foundation of the developed method and its validation through highly accurate experimental data it can be concluded that new criterion is credible for the determination of the SOC.


Author(s):  
S Sinha ◽  
A K Agarwal

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.


2011 ◽  
Vol 138-139 ◽  
pp. 870-873
Author(s):  
Pei Gang Jiao ◽  
Shao Fu Shan ◽  
Qiu Hua Miao

In this paper, three-dimensional automatic fuel measuring device of diesel engine test bed was created. The function of virtual assembly was achieved using virtual reality modeling language. Network virtual assembly can operate, browse and assemble automatic fuel measuring device remotely by embedding virtual assembly in web pages. The virtual assembly method presented in this paper can be easily extended to deal with many other problems in engineering system if control parameters are modified properly.


2019 ◽  
Author(s):  
Tobias Michler ◽  
Johannes Dörnhöfer ◽  
Daniel Erforth ◽  
Alexander Heinz ◽  
Kai Scheiber ◽  
...  

2019 ◽  
Author(s):  
Niccolò Fiorini ◽  
Luca Romani ◽  
Giovanni Ferrara ◽  
Alessandro Bianchini ◽  
Niccolò Ciuffi ◽  
...  

Author(s):  
Ahmed Al-Durra ◽  
Marcello Canova ◽  
Stephen Yurkovich

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).


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