Drive Cycle Efficiency and Emissions Estimates for Reactivity Controlled Compression Ignition in a Multi-Cylinder Light-Duty Diesel Engine

2011 ◽  
Author(s):  
Scott J. Curran ◽  
Kukwon Cho ◽  
Thomas E. Briggs ◽  
Robert M. Wagner
Keyword(s):  
Diesel Engine ◽  
Pressure Rise ◽  
Injection System ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Drive Cycle ◽  
Reactivity Controlled Compression Ignition ◽  
Pressure Rise Rate ◽  
Light Duty ◽  
Rise Rate

In-cylinder blending of gasoline and diesel to achieve Reactivity Controlled Compression Ignition (RCCI) has been shown to reduce NOx and PM emissions while maintaining or improving brake thermal efficiency (BTE) as compared to conventional diesel combustion (CDC). The RCCI concept has an advantage over many advanced combustion strategies in that by varying both the percent of premixed gasoline and EGR rate, stable combustion can be extended over more of the light-duty drive cycle load range. Changing the percent of premixed gasoline changes the fuel reactivity stratification in the cylinder providing further control of combustion phasing and cylinder pressure rise rate than the use of EGR alone. This paper examines the combustion and emissions performance of light-duty diesel engine using direct injected diesel fuel and port injected gasoline to enable RCCI for steady-state engine conditions which are consistent with a light-duty drive cycle. A GM 1.9L four-cylinder engine with the stock compression ratio of 17.5:1, common rail diesel injection system, high-pressure EGR system and variable geometry turbocharger was modified to allow for port fuel injection with gasoline. Engine-out emissions, engine performance and combustion behavior for RCCI operation is compared against both CDC and a premixed charge compression ignition (PCCI) strategy which relies on high levels of EGR dilution. The effect of percent of premixed gasoline, EGR rate, boost level, intake mixture temperature, combustion phasing, and cylinder pressure rise rate is investigated for RCCI combustion for the light-duty modal points. Engine-out emissions of NOx and PM were found to be considerably lower for RCCI operation as compared to CDC and PCCI, while HC and CO emissions were higher. BTE was similar or higher for many of the modal conditions for RCCI operation. The emissions results are used to estimate hot-start FTP-75 emissions levels with RCCI and are compared against CDC and PCCI modes.

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.

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.

Postinjection Strategy for the Reduction of the Peak Pressure Rise Rate of Neat n-Butanol Combustion

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Marko Jeftić ◽  
Ming Zheng
Keyword(s):  
Nitrogen Oxide ◽  
Thermal Efficiency ◽  
Peak Pressure ◽  
Pressure Rise ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Compression Ignition Engine ◽  
Pressure Rise Rate ◽  
Rise Rate ◽  
Load Conditions

Enhanced premixed combustion of neat butanol in a compression ignition engine can have challenges with regards to the peak pressure rise rate (PRR) and the peak in-cylinder pressure. It was proposed to utilize a butanol postinjection to reduce the peak PRR and the peak in-cylinder pressure while maintaining a constant engine load. Postinjection timing and duration sweeps were carried out with neat n-butanol in a compression ignition engine. The postinjection timing sweep results indicated that the use of an early butanol postinjection reduced the peak PRR and the peak in-cylinder pressure and it was observed that there was an optimal postinjection timing range for the maximum reduction of these parameters. The results also showed that an early postinjection of butanol increased the nitrogen oxide emissions, and a Fourier transform infrared spectroscopy (FTIR) analysis revealed that late postinjections increased the emissions of unburned butanol. The postinjection duration sweep indicated that the peak PRR was significantly reduced by increasing the postinjection 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 postinjection 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 postinjection duration was increased. The results also showed that there were increased nitrogen oxide, carbon monoxide, and total hydrocarbon (THC) emissions for larger postinjections. Although the use of a postinjection resulted in emission and thermal efficiency penalties at medium load conditions, the results demonstrated that the postinjection strategy successfully reduced the peak PRR, and this characteristic can be potentially useful for higher load applications where the peak PRR is of greater concern.

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%.

Accelerometer Signal to Characterize the Combustion Development in Multiple Injection Diesel Engine

2012 ◽  
Author(s):  
G. Chiatti ◽  
O. Chiavola ◽  
E. Recco
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Vibration Signal ◽  
Injection System ◽  
Cylinder Pressure ◽  
Multiple Injection ◽  
Real Time Control ◽  
Common Rail Injection System ◽  
Crank Angle

This work constitutes one of the last steps of a comprehensive research program in which vibration sensors are used with the purpose of developing and setting up a methodology that is able to perform a real time control of the combustion process by means of non-intrusive measurements. Previous obtained and published results have demonstrated that a direct relationship exists between in-cylinder pressure and engine block vibration signals. The analysis of the processed data have highlighted that the block vibration signal may be used to locate, in the crank–angle domain, the combustion phases (the start of the combustion, the crank angle value corresponding to the beginning of main combustion and to the in-cylinder pressure maximum value) and to quantify the in-cylinder pressure development by evaluating the pressure peak value and the pressure rise rate caused by the combustion process. The aim of this work is to extend and validate the developed methodology when a multiple-injection strategy is imposed on the engine. The paper presents the results obtained during the experimentation of a two cylinder diesel engine equipped with a common rail injection system, that was performed in the Laboratory of the Mechanical and Industrial Department of ‘ROMA TRE’ University. During the tests, a wide variation of the injection parameters settings is imposed on the engine (timing and duration) in its complete operative field.

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.

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