A Study to Determine Factors That Have Influence on the Propensity of Natural LSPI Occurring in GTDI Engines

Author(s):  
Paras Sethi ◽  
Eric Passow ◽  
Kimm Karrip ◽  
Max Maschewske ◽  
Jason Bieneman ◽  
...  

There are many articles and papers published about the developments in engine downsizing as an effective means in reducing vehicle fuel consumption while improving engine performance. The increase in performance of gasoline turbo charged direct injected (GTDI) engines, in conjunction with diverse vehicle platform performance targets (i.e. towing capability) and higher gear transmissions pushes the engine to operate with higher torques at lower engine speeds. This operating condition has increased the propensity of an abnormal combustion event, known as Low Speed Pre-Ignition (LSPI) or Stochastic Pre-Ignition (SPI). The power cylinder unit (PCU) components exposed to this pre-ignition event can experience failure. The engine manufacturers, as well as MAHLE, continue to ensure engine and PCU component survivability against LSPI by performing life cycle robustness testing. MAHLE’s research of LSPI continues to focus on the robustness of PCU components in the presence of LSPI events, as well as investigating design developments that have the potential to minimize the propensity of LSPI to occur. The test procedure development for evaluating natural LSPI events will be presented. Various test results and parameter sensitivities that were documented during this procedure development, along with the many challenges associated with engine performance repeatability will be discussed. Parameters that were found to influence LSPI propensity, as well as parameters that were found not to influence LSPI propensity will be discussed.

Author(s):  
Ihor S. Diakunchak ◽  
David R. Nevin

The site performance testing of CW251B10 industrial gas turbine engines is described in this paper. A brief description is provided of the test procedure, the special instrumentation used during the test, and the derivation of the test tolerances. The test data analysis method and the associated correction curves and tables are described in some detail. Typical engine site performance test results are presented and compared to the original predicted engine performance.


2020 ◽  
Vol 24 (1) ◽  
pp. 72-87 ◽  
Author(s):  
Sara Tayari ◽  
Reza Abedi ◽  
Ali Abedi

AbstractMicroalgae have been mentioned as a promising feedstock for biodiesel production. In this study, microalgae Chlorella vulgaris (MCV) was cultivated in a bioreactor with wastewater. After biodiesel production from MCV oil via transesterification reaction, chemical and physical properties of MCV methyl ester were evaluated with regular diesel and ASTM standard. Besides, engine performance and exhaust emissions of CI engine fuelled with the blends of diesel-biodiesel were measured. The GC-MS analysis showed that oleic and linoleic acids were the main fatty acid compounds in the MCV methyl ester. Engine test results revealed that the use of biodiesel had led to a major decrease in CO and HC emissions and a modest reduction in CO2 emissions, whereas there was a minor increase in NOx emissions. Furthermore, there was a slight decrease in the engine power and torque while a modest increase in brake specific fuel consumption which are acceptable due to exhaust emissions reduction. The experimental results illustrate considerable capabilities of applied MVC biodiesel as an alternative fuel in diesel engines to diminish the emissions.


2017 ◽  
Vol 55 (8) ◽  
pp. 1112-1114 ◽  
Author(s):  
Giuseppe Lippi ◽  
Gianfranco Cervellin ◽  
Mario Plebani

AbstractThe management of laboratory data in unsuitable (hemolyzed) samples remains an almost unresolved dilemma. Whether or not laboratory test results obtained by measuring unsuitable specimens should be made available to the clinicians has been the matter of fierce debates over the past decades. Recently, an intriguing alternative to suppressing test results and recollecting the specimen has been put forward, entailing the definition and implementation of specific algorithms that would finally allow reporting a preanalytically altered laboratory value within a specific comment about its uncertainty of measurement. This approach carries some advantages, namely the timely communication of potentially life-threatening laboratory values, but also some drawbacks. These especially include the challenging definition of validated performance specifications for hemolyzed samples, the need to producing reliable data with the lowest possible uncertainty, the short turnaround time for repeating most laboratory tests, the risk that the comments may be overlooked in short-stay and frequently overcrowded units (e.g. the emergency department), as well as the many clinical advantages of a direct communication with the physician in charge of the patient. Despite the debate remains open, we continue supporting the suggestion that suppressing data in unsuitable (hemolyzed) samples and promptly notifying the clinicians about the need to recollect the samples remains the most (clinically and analytically) safe practice.


Author(s):  
P. A. Karpovich ◽  
A. I. Masters

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been shown to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.


2021 ◽  
Vol 15 (4) ◽  
pp. 581-584
Author(s):  
Božo Bujanić ◽  
Matija Košak

The paper presents and describes the procedure of testing the materials that were available for the production of a multifunctional protective helmet. The procedure was carried out at the company Šestan-Busch d.o.o. as part of the EU project for the development and production of a multifunctional protective helmet. The test results showed that carbon fibers polymers as a composite material have the best impact absorption properties which was a key criterion for material selection. Other materials; glass fibers polymers, aramid fibers polymers and combinations in the test procedure showed worse results compared to the selected criterion.


Author(s):  
J. B. Brown-Gilpin

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.


1985 ◽  
Vol 107 (3) ◽  
pp. 769-774
Author(s):  
P. A. Karpovich ◽  
A. I. Masters

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been show to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.


Author(s):  
Yin Dai ◽  
Daoyun Qiu ◽  
Yang Wang ◽  
Sizhe Dong ◽  
Hong-Li Wang

Alzheimer’s disease is the third most expensive disease, only after cancer and cardiopathy. It is also the fourth leading cause of death in the elderly after cardiopathy, cancer, and cerebral palsy. The disease lacks specific diagnostic criteria. At present, there is still no definitive and effective means for preclinical diagnosis and treatment. It is the only disease that cannot be prevented and cured among the world’s top ten fatal diseases. It has now been proposed as a global issue. Computer-aided diagnosis of Alzheimer’s disease (AD) is mostly based on images at this stage. This project uses multi-modality imaging MRI/PET combining with clinical scales and uses deep learning-based computer-aided diagnosis to treat AD, improves the comprehensiveness and accuracy of diagnosis. The project uses Bayesian model and convolutional neural network to train experimental data. The experiment uses the improved existing network model, LeNet-5, to design and build a 10-layer convolutional neural network. The network uses a back-propagation algorithm based on a gradient descent strategy to achieve good diagnostic results. Through the calculation of sensitivity, specificity and accuracy, the test results were evaluated, good test results were obtained.


Author(s):  
Shiv Kumar ◽  
Agrima Yadav ◽  
Deepak Kumar Sharma

The exponential growth in the world population has led to an ever-increasing demand for food supplies. This has led to the realization that conventional and traditional methods alone might not be able to keep up with this demand. Smart agriculture is being regarded as one of the few realistic ways that, together with the traditional methods, can be used to close the gap between the demand and supply. Smart agriculture integrates the use of different technologies to better monitor, operate, and analyze different activities involved in different phases of the agricultural life cycle. Smart agriculture happens to be one of the many disciplines where deep learning and computer vision are being realized to be of major impact. This chapter gives a detailed explanation of different deep learning methods and tries to provide a basic understanding as to how these techniques are impacting different applications in smart agriculture.


2020 ◽  
Vol 11 (1) ◽  
pp. 17 ◽  
Author(s):  
Huijun Liu ◽  
Fenfang Chen ◽  
Yuxiang Tong ◽  
Zihang Wang ◽  
Xiaoli Yu ◽  
...  

The aging of lithium-ion batteries (LIBs) is a crucial issue and must be investigated. The aging rate of LIBs depends not only on the material and electrochemical performance but also on the working conditions. In order to assess the impact of vehicle driving conditions, including the driving cycle, ambient temperature, charging mode, and trip distance on the battery life cycle, this paper first establishes an electric vehicle (EV) energy flow model to solve the operating parameters of the battery pack while working. Then, a powertrain test is carried out to verify the simulation model. Based on the simulated data under different conditions, the battery capacity fade process is estimated by using a semi-empirical aging model. The mileage (Ф) traveled by the vehicle before the end of life (EOL) of the battery pack is then calculated and taken as the evaluation index. The results indicate that the Ф is higher when the vehicle drives the Japanese chassis dynamometer test cycle JC08 than in the New European Driving Cycle (NEDC) and the Federal Test Procedure (FTP-75). The Ф will be dramatically reduced at both low and high ambient temperatures. Fast charging can increase the Ф at low ambient temperatures, whereas long trip driving can always increase Ф to varying degrees.


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