Safe operation of dual-fuel engines using constrained stochastic control

2021 ◽  
pp. 146808742098510
Author(s):  
Carlos Guardiola ◽  
Benjamín Pla ◽  
Pau Bares ◽  
Alvin Barbier
Keyword(s):  
Pressure Rise ◽  
Maximum Amplitude ◽  
Dual Fuel ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Safe Operation ◽  
Pressure Oscillations ◽  
Engine Operation ◽  
Pressure Rise Rate ◽  
Rise Rate

Premixed combustion strategies have the potential to achieve high thermal efficiency and to lower the engine-out emissions such as NOx. However, the combustion is initiated at several kernels which create high pressure gradients inside the cylinder. Similarly to knock in spark ignition engines, these gradients might be responsible of important pressure oscillations with a harmful potential for the engine. This work aims to analyze the in-cylinder pressure oscillations in a dual-fuel combustion engine and to determine the feedback variables, control actuators, and control approach for a safe engine operation. Three combustion modes were examined: fully, highly, and partially premixed, and three indexes were analyzed to characterize the safe operation of the engine: the maximum pressure rise rate, the ringing intensity, and the maximum amplitude of pressure oscillations (MAPO). Results show that operation constraints exclusively based on indicators such as the pressure rise rate are not sufficient for a proper limitation of the in-cylinder pressure oscillations. This paper explores the use of a knock-like controller for maintaining the resonance index magnitude under a predefined limit where the gasoline fraction and the main injection timing were selected as control variables. The proposed strategy shows the ability to maintain the percentage of cycles exceeding the specified limit at a desired threshold at each combustion mode in all the cylinders.

Performance of Dual Fuel Engine Running on Jojoba Oil as Pilot Fuel and CNG or LPG

2007 ◽  
Author(s):  
Mohamed Y. E. Selim ◽  
M. S. Radwan ◽  
H. E. Saleh
Keyword(s):  
Methyl Ester ◽  
Natural Gas ◽  
Pressure Rise ◽  
Combustion Noise ◽  
Dual Fuel ◽  
Maximum Pressure ◽  
Injection Timing ◽  
Pressure Rise Rate ◽  
Rise Rate ◽  
Pilot Fuel

The use of Jojoba Methyl Ester as a pilot fuel was investigated for almost the first time as a way to improve the performance of dual fuel engine running on natural gas or LPG at part load. The dual fuel engine used was Ricardo E6 variable compression diesel engine and it used either compressed natural gas (CNG) or liquefied petroleum gas (LPG) as the main fuel and Jojoba Methyl Ester as a pilot fuel. Diesel fuel was used as a reference fuel for the dual fuel engine results. During the experimental tests, the following have been measured: engine efficiency in terms of specific fuel consumption, brake power output, combustion noise in terms of maximum pressure rise rate and maximum pressure, exhaust emissions in terms of carbon monoxide and hydrocarbons, knocking limits in terms of maximum torque at onset of knocking, and cyclic data of 100 engine cycle in terms of maximum pressure and its pressure rise rate. The tests examined the following engine parameters: gaseous fuel type, engine speed and load, pilot fuel injection timing, pilot fuel mass and compression ratio. Results showed that using the Jojoba fuel with its improved properties has improved the dual fuel engine performance, reduced the combustion noise, extended knocking limits and reduced the cyclic variability of the combustion.

Post Injection Strategy for the Reduction of the Peak Pressure Rise Rate of Neat N-Butanol Combustion

2015 ◽  
Author(s):  
Marko Jeftić ◽  
Ming Zheng
Keyword(s):  
Peak Pressure ◽  
Pressure Rise ◽  
Injection Timing ◽  
Post Injection ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Compression Ignition Engine ◽  
Pressure Rise Rate ◽  
Injection Duration ◽  
Rise Rate

Enhanced premixed combustion of neat butanol in a compression ignition engine can have challenges with regards to the peak pressure rise rate and the peak in-cylinder pressure. It was proposed to utilize a butanol post injection to reduce the peak pressure rise rate and the peak in-cylinder pressure while maintaining a constant engine load. Post injection timing and duration sweeps were carried out with neat n-butanol in a compression ignition engine. The post injection timing sweep results indicated that the use of an early butanol post injection reduced the peak pressure rise rate and the peak in-cylinder pressure and it was observed that there was an optimal post injection timing range for the maximum reduction of these parameters. The results also showed that an early post injection of butanol increased the nitrogen oxide emissions and an FTIR analysis revealed that late post injections increased the emissions of unburned butanol. The post injection duration sweep indicated that the peak pressure rise rate was significantly reduced by increasing the post injection duration at constant load conditions. There was also a reduction in the peak in-cylinder pressure. Measurements with a hydrogen mass spectrometer showed that there was an increased presence of hydrogen in the exhaust gas when the post injection duration was increased but the total yield of hydrogen was relatively low. It was observed that the coefficient of variation for the indicated mean effective pressure was significantly increased and that the indicated thermal efficiency was reduced when the post injection duration was increased. The results also showed that there were increased nitrogen oxide, carbon monoxide, and total hydrocarbon emissions for larger post injections. Although the use of a post injection resulted in emission and thermal efficiency penalties at medium load conditions, the results demonstrated that the post injection strategy successfully reduced the peak pressure rise rate and this characteristic can be potentially useful for higher load applications where the peak pressure rise rate is of greater concern.

Effect of Dual Fuel Engine Parameters and Fuel Type on Engine Noise Emissions

2010 ◽  
Author(s):  
Emad Elnajjar ◽  
Mohamed Y. E. Selim ◽  
Farag Omar
Keyword(s):  
Compression Ratio ◽  
Engine Speed ◽  
Pressure Rise ◽  
Dual Fuel ◽  
Operating Parameters ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Fuel Type ◽  
Rise Rate ◽  
Crank Angle

Investigating experimentally the effects of different fuel types and engine parameters on the overall generated engine noise levels. Engine parameters such as: Engine speed, Injection timing angle, engine loading, different pilot fuel to gases fuel ratio and engine compression ratio. Engine noises due to combustion, turbulent flow and motoring were reported in this study by direct sound pressure level SPL (dB) measurements and compared to the maximum cylinder pressure rise rate with respect to the engine crank angle (dP/dθ)max. Experimental procedures conducted using a Ricardo diesel version variable compression research engine. The study was conducted for three different fuels: single diesel fuel, and dual fuel engine that uses LPG or natural gas. The study for each fuel type covered the following operating parameters range, engine speed from 20–28 rev/sec, injection timing form 20 to 45° BTDC, compression ratio from 16 to 22, load range 2 to 14 N.m, and ratio of pilot to gaseous fuel from 0 to 10%. The study reported the location (crank angle) corresponding to maximum cylinder pressure and max pressure rise rate. Results from testing dual fuel engine with varying design and operating parameters are presented and discussed. The present work reported higher SPL (dB) generated from burning a dual fuel compared to burning diesel fuel only.

Combustion Noise Investigation With Multi-Cylinder RCCI

2013 ◽  
Author(s):  
Scott J. Curran ◽  
James P. Szybist ◽  
Robert M. Wagner
Keyword(s):  
Pressure Rise ◽  
Combustion Noise ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Engine Operation ◽  
Reactivity Controlled Compression Ignition ◽  
Pressure Rise Rate ◽  
Advanced Combustion ◽  
Rise Rate ◽  
Noise Metrics

Advanced combustion techniques have shown promise for achieving high thermal efficiency with simultaneous reductions in oxides of nitrogen (NOx) and particulate matter (PM) emissions. Many advanced combustion studies have used some form of noise-related metric to constrain engine operation, whether it be cylinder pressure rise rate, combustion noise, or ringing intensity. As the development of advanced combustion techniques progresses towards production-viable concepts, combustion noise is anticipated to be of the upmost concern for consumer acceptability. This study compares the noise metrics of cylinder pressure rise rate with combustion noise as measured by an AVL combustion noise meter over a wide range of engine operation conditions with reactivity controlled compression ignition on a light-duty multi-cylinder diesel engine modified to allow for direct injection of diesel fuel and port fuel injection of gasoline. Key parameters affecting noise metrics are engine load, speed, and the amount of boost. The trade-offs between high efficiency, low NOX emissions, and combustion noise were also explored. Additionally, the combustion noise algorithm integrated into the Drivven combustion analysis toolkit is compared to cylinder pressure rise rate and combustion noise as measured with a combustion noise meter. It is shown that the combustion noise of the multi-cylinder reactivity controlled compression ignition map can approach 100 dB while keeping the maximum pressure rise under 100 kPa/CAD.

Combustion parameter evaluation of diesel engine via vibration acceleration signal

2021 ◽  
pp. 146808742110308
Author(s):  
Pan Zhang ◽  
Wenzhi Gao ◽  
Yong Li ◽  
Zhaoyi Wei
Keyword(s):  
Peak Pressure ◽  
Pressure Rise ◽  
Peak Position ◽  
Maximum Pressure ◽  
Cylinder Pressure ◽  
Combustion Control ◽  
Pressure Rise Rate ◽  
Acceleration Signal ◽  
Rise Rate ◽  
Start Of Combustion

Efficient combustion control has increasingly become a quality requirement for automobile manufacturers because of its impact on pollutant and greenhouse gas emissions. In view of this, the management system development of modern internal combustion engines is mainly aimed at combustion control. The real-time detection of in-cylinder pressure characteristic parameters has a considerable significance on the closed-loop combustion control of the internal combustion engine. This paper presents a detection method in which the start of combustion, peak pressure, maximum pressure rise rate, and phase of maximum pressure rise rate are identified through vibration acceleration signal. In order to analyze the relationship between vibration and in-cylinder pressure signal, experimental data are acquired in a diesel engine by implementing various injection strategies and engine operating conditions (speed and load). The results show that the start of combustion can be detected by analyzing its relationship with the peak position of the filtered vibration signal, and the phase of the maximum pressure rise rate can be identified by examining its relationship with the zero-cross position that is adjacent to the right of the peak position. Moreover, the filtered vibration signals are also truncated in the same length and utilized as inputs for algorithms to detect the peak pressure and the maximum pressure rise rate. The algorithms are mainly performed on data compression (or feature extraction) and target regression. Major algorithms, such as one-dimensional convolutional neural network, compression sensing, wavelet decomposition, multilayer perceptron, and support vector machine, are tested. Various experimental results verify that for the test engine the phase detection accuracy of the start of combustion and maximum pressure rise rate is less than 1.7°CA for a 95% prediction interval width. For the detection of the peak pressure and maximum pressure rise rate, the normalized error threshold is set as 0.05, then the accuracies can be not less than 95%.

High load expansion with low emissions and the pressure rise rate by dual-fuel combustion

2018 ◽  
Vol 144 ◽  
pp. 437-443 ◽  
Author(s):  
Sanghyun Chu ◽  
Jeongwoo Lee ◽  
Jaegu Kang ◽  
Yoonwoo Lee ◽  
Kyoungdoug Min
Keyword(s):  
Pressure Rise ◽  
Fuel Combustion ◽  
High Load ◽  
Dual Fuel ◽  
Pressure Rise Rate ◽  
Rise Rate ◽  
Dual Fuel Combustion

scholarly journals Capturing Pressure Oscillations in Numerical Simulations of Internal Combustion Engines

2017 ◽  
Author(s):  
Sreenivasa Rao Gubba ◽  
Ravichandra S. Jupudi ◽  
Shyam Sundar Pasunurthi ◽  
Sameera D. Wijeyakulasuriya ◽  
Roy J. Primus ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Cylinder Pressure ◽  
Pressure Oscillations ◽  
Engine Operation ◽  
Numerical Predictions ◽  
Medium Speed ◽  
Dual Fuel Combustion ◽  
The Mean

In an earlier publication [1] the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from CFD. In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with those measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier Transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.

Preliminary Investigation of Direct Injection Neat n-Butanol in a Diesel Engine

2013 ◽  
Author(s):  
Tadanori Yanai ◽  
Xiaoye Han ◽  
Graham T. Reader ◽  
Ming Zheng ◽  
Jimi Tjong
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Preliminary Investigation ◽  
Pressure Rise ◽  
Injection Pressure ◽  
Injection Timing ◽  
Boost Pressure ◽  
Pressure Rise Rate ◽  
Rise Rate ◽  
Short Period

The characteristics of combustion, emissions, and thermal efficiency of a diesel engine with direct injection neat n-butanol were investigated. Tests were conducted on a single cylinder water-cooled four stroke direct injection diesel engine. The engine ran at a load of 6.5 ∼ 8.0 bar IMEP at 1500 rpm engine speed and the injection pressure was controlled to 900 bar. The intake boost pressure, injection timing and EGR rate were adjusted to investigate the engine performance. The test results showed that significantly longer ignition delays were possible when using butanol compared to diesel fuel. Butanol usage generally led to a rapid heat release in a short period, resulting in excessively high pressure rise rate. The pressure rise rate was reduced by retarding the injection timing. The butanol injection timing was limited by misfire and pressure rise rate. Thus, the ignition timing controllable window by injection timing was much narrower than that of diesel. The neat butanol combustion produced near zero soot and very low NOx emissions even at low EGR rate. The tests demonstrated that neat butanol had the potential to achieve ultra-low emissions. However, challenges related to reducing the pressure rise rate and improving the ignition controllability were identified.

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