An Engine-Starting Simulation With Friction Estimation: Background and Model Validation

2003 ◽  
Author(s):  
Rassem R. Henry
Keyword(s):  
Performance Prediction ◽  
Engine Performance ◽  
Friction Torque ◽  
Valve Train ◽  
Physical Parameters ◽  
Test Results ◽  
First Case ◽  
Friction Models ◽  
Engine Friction ◽  
Friction Estimation

This paper describes an engine-starting simulation that uses models of the electrical, engine dynamics and engine thermodynamics subsystems combining them with engine friction models. One of these friction models uses the physical parameters of the engine as basis for estimating the friction torque. This allows engine performance prediction, hence the ability to size the electrical starting system, without engine availability. The resultant simulation is developed using SIMULINK/MATLAB™ and it has been validated for two engines; the first is a 4-cylinder engine with a conventional valve train, and relatively high friction by today’s standards, and the second is a more recent 3-cylinder engine with lowfriction. Validation of the first engine was done based on matching its published starting tests with results obtained using this paper’s simulation. The validation of the second engine was carried out by comparing engine test results with simulation results. Tests in the first case were for engine starting including firing and in the second case were for cranking only conditions.

scholarly journals Investigation on Physicochemical Properties of Wastewater Grown Microalgae Methyl Ester and its Effects on CI Engine

2020 ◽  
Vol 24 (1) ◽  
pp. 72-87 ◽  
Author(s):  
Sara Tayari ◽  
Reza Abedi ◽  
Ali Abedi
Keyword(s):  
Methyl Ester ◽  
Engine Performance ◽  
Exhaust Emissions ◽  
Biodiesel Production ◽  
Emissions Reduction ◽  
Test Results ◽  
Main Fatty Acid ◽  
Ci Engine ◽  
Hc Emissions ◽  
A Minor

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.

A Study of the Effects of Ceramic Valve Train Parts on Reduction of Engine Friction

1997 ◽  
Author(s):  
Hiromu Izumida ◽  
Takao Nishioka ◽  
Akira Yamakawa ◽  
Masamichi Yamagiwa
Keyword(s):  
Valve Train ◽  
Engine Friction

Inter-Bolt Variability of Cotton Duck #4 and the Effects on Cigarette Ignition Propensity Test Outcome

1995 ◽  
Vol 13 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Richard Jupe ◽  
Donald K. Shipley ◽  
William Z. Hudson ◽  
Joseph T. Wanna ◽  
Linda C. Greear
Keyword(s):  
Test Methods ◽  
Physical Parameters ◽  
Test Results ◽  
Astm Method ◽  
Significant Difference ◽  
Ignition Propensity

Two bolts of cotton duck fabric that meet military specifications and the purchasing guidelines described by the National Institute of Standards and Technology (NIST) for use as a substrate in "Test Methods for Quantifying the Propensity of Cigarettes to Ignite Soft Furnishings" were tested with smoldering cigarettes to determine the effect of inter-bolt variations on cigarette ignition propensity test outcome. The test was designed around an ASTM method that calls for the control of all known test variables, except for those inherent to the fabric's manufacture. The ignitability of each fabric was determined by testing two sets of 48 replications for each of two experimental cigarettes. The two bolts of cotton duck fabric showed a statistically significant difference in ignitions, independent of environmental and experimental fac tors. Two additional bolts of cotton duck #4 were analyzed. Cigarette ignition test results and the physical parameters of the additional bolts offer evidence that the NIST specifications are difficult to meet and further that test results are extremely sensitive to fabric properties.

scholarly journals AI-Empowered Computational Examination of Chest Imaging for COVID-19 Treatment: A Review

2021 ◽  
Vol 4 ◽  
Author(s):  
Hanqiu Deng ◽  
Xingyu Li
Keyword(s):  
False Negative ◽  
Screening Tools ◽  
Polymerase Chain Reaction Test ◽  
Test Results ◽  
First Case ◽  
Lung Scan ◽  
Screening Efficiency ◽  
Polymerase Chain ◽  
Chain Reaction Test ◽  
Full Swing

Since the first case of coronavirus disease 2019 (COVID-19) was discovered in December 2019, COVID-19 swiftly spread over the world. By the end of March 2021, more than 136 million patients have been infected. Since the second and third waves of the COVID-19 outbreak are in full swing, investigating effective and timely solutions for patients’ check-ups and treatment is important. Although the SARS-CoV-2 virus-specific reverse transcription polymerase chain reaction test is recommended for the diagnosis of COVID-19, the test results are prone to be false negative in the early course of COVID-19 infection. To enhance the screening efficiency and accessibility, chest images captured via X-ray or computed tomography (CT) provide valuable information when evaluating patients with suspected COVID-19 infection. With advanced artificial intelligence (AI) techniques, AI-driven models training with lung scans emerge as quick diagnostic and screening tools for detecting COVID-19 infection in patients. In this article, we provide a comprehensive review of state-of-the-art AI-empowered methods for computational examination of COVID-19 patients with lung scans. In this regard, we searched for papers and preprints on bioRxiv, medRxiv, and arXiv published for the period from January 1, 2020, to March 31, 2021, using the keywords of COVID, lung scans, and AI. After the quality screening, 96 studies are included in this review. The reviewed studies were grouped into three categories based on their target application scenarios: automatic detection of coronavirus disease, infection segmentation, and severity assessment and prognosis prediction. The latest AI solutions to process and analyze chest images for COVID-19 treatment and their advantages and limitations are presented. In addition to reviewing the rapidly developing techniques, we also summarize publicly accessible lung scan image sets. The article ends with discussions of the challenges in current research and potential directions in designing effective computational solutions to fight against the COVID-19 pandemic in the future.

scholarly journals Study on the Water-Physical Properties of the Cement-Plaster Bonded Rock-Like Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yong Zhang ◽  
Zhiguo Cao ◽  
Xiaomeng Shi
Keyword(s):  
Physical Properties ◽  
Physical Model ◽  
Coupling Model ◽  
Model Tests ◽  
Physical Parameters ◽  
Test Results ◽  
Physical Model Tests ◽  
Fluid Coupling ◽  
Softening Coefficient ◽  
Solid Fluid Coupling

The cement-plaster bonded rock-like material is one of the most commonly used materials to simulate different rocks in physical model tests. However, the applicability of this material in solid-fluid coupling model tests is not clear because there are few research studies on the water-physical properties of this material and its similarity to the actual rock is uncertain. This paper presents a systemic experimental study on the water-physical properties of the cement-plaster bonded rock-like materials. The parameters of rock-like materials, including water absorption, softening coefficient, and permeability coefficient, were compared with those of actual rocks to analyse the applicability of such material. Then, the influence of proportion on the water-physical properties of this material was discussed. By multiple regression analysis of the test results, empirical equations between the water-physical parameters and proportions were proposed. The equations can be used to estimate the water-physical properties of cement-plaster bonded rock-like materials with specific proportion and thus to select suitable materials in the solid-fluid coupling physical model tests.

Performance Analysis and Improvement Approach of HEV Extended Expansion Gasoline Engine

2011 ◽  
Vol 317-319 ◽  
pp. 1999-2006
Author(s):  
Yu Wan ◽  
Ai Min Du ◽  
Da Shao ◽  
Guo Qiang Li
Keyword(s):  
Mathematical Model ◽  
Performance Analysis ◽  
Fuel Consumption ◽  
Economic Performance ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Valve Train ◽  
Gasoline Engines ◽  
Simulation Results ◽  
Negative Impacts

According to the boost mathematical model verified by experiments, the valve train of traditional gasoline engine is optimized and improved to achieve extended expansion cycle. The simulation results of extended expansion gasoline engine shows that the extended expansion gasoline engine has a better economic performance, compared to traditional gasoline engines. The average brake special fuel consumption (BSFC) can reduce 22.78 g / kW•h by LIVC, but the negative impacts of extended expansion gasoline engine restrict the potential of extended expansion gasoline engine. This paper analyzes the extended expansion gasoline engine performance under the influence of LIVC, discusses the way to further improve extended expansion gasoline engine performance.

Clearance and Dry Friction Study in a Nonlinear Torsional Vibration of a Rotating Machinery

1999 ◽  
Author(s):  
Kazuki Mizutani ◽  
Hossain Md. Zahid
Keyword(s):  
Torsional Vibration ◽  
Dry Friction ◽  
Friction Torque ◽  
Frictional Property ◽  
Behavioral Characteristics ◽  
Spring Stiffness ◽  
Response Curves ◽  
Friction Models ◽  
The Difference ◽  
Friction Study

Abstract Clearance problem in coupling is often experienced in a rotary torsional vibration system. We tried to analyze the qualitative and quantitative characteristics of torsional vibration by modeling the bilinear spring stiffness with changing friction torque. Symmetric and asymmetric spring stiffness with friction models are developed to investigate the behavioral characteristics of the system for simulations and experiments. The frequency response curves and time response curves with external sinusoidal excitation are observed by several non-dimensional numerical simulations. The thoroughly experiments are done to understand the actual phenomena of torsional vibration, verification of models and adjustability of simulations. The frictional property considered as dry friction in coupling is found very significant parameter to reduce the vibration within a tolerable range in both of the simulations and experiments. The difference between the results getting from simulations and experiments are also demonstrated in this paper elaborately.

Nonsteady Aerodynamics of the Comprex Supercharger

1958 ◽  
Author(s):  
Hans U. Burri
Keyword(s):  
Method Of Characteristics ◽  
Engine Performance ◽  
Engine Test ◽  
Nonsteady Flow ◽  
Test Results ◽  
One Dimensional ◽  
Acceptable Accuracy ◽  
The Method Of Characteristics ◽  
Performance Point

A brief outline is given of the method of characteristics for the analysis of one-dimensional nonsteady flow. Two typical types of experiments are discussed which indicate the degree of accuracy possible if this method is applied to machinery like the Comprex supercharger. As an example, a typical analysis is presented for one particular engine-performance point. It is possible to duplicate engine test results with acceptable accuracy.

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