Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn 4-Stroke Natural Gas Engine: Experimental Results

2006 ◽  
Author(s):  
Kris Quillen ◽  
Rudolf H. Stanglmaier ◽  
Luke Moughon ◽  
Rosalind Takata ◽  
Victor Wong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Piston Ring ◽  
Department Of Energy ◽  
Experimental Results ◽  
Friction Reduction ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Computational Tools ◽  
Ring Pack ◽  
Institute Of Technology

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT) and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the US Department of Energy. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼ 0.50% improvement in mechanical efficiency (ηmech).

Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn Four-Stroke Natural Gas Engine: Experimental Results

2007 ◽  
Vol 129 (4) ◽  
pp. 1088-1094
Author(s):  
Kris Quillen ◽  
Rudolf H. Stanglmaier ◽  
Luke Moughon ◽  
Rosalind Takata ◽  
Victor Wong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Piston Ring ◽  
Department Of Energy ◽  
Experimental Results ◽  
Friction Reduction ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Computational Tools ◽  
Ring Pack ◽  
Institute Of Technology

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT), and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the U.S. Department of Energy. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼0.50% improvement in mechanical efficiency (ηmech).

Friction Reduction Due to Lubrication Oil Changes in a Lean-Burn 4-Stroke Natural Gas Engine: Experimental Results

2007 ◽  
Author(s):  
Kris Quillen ◽  
Rudolph H. Stanglmaier ◽  
Victor Wong ◽  
Ed Reinbold ◽  
Rick Donahue ◽  
...  
Keyword(s):  
Natural Gas ◽  
Department Of Energy ◽  
Experimental Results ◽  
Friction Reduction ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Computational Tools ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Lubrication Oil

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT), Colorado State University (CSU), and ExxonMobil. This project is part of the Advanced Reciprocating Engine System (ARES) program led by the US Department of Energy. Changes in lubrication oil have been identified as a way to potentially help meet the ARES goal of developing a natural gas engine with 50% brake thermal efficiency. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various lubrication oil parameters on engine friction. These computational tools were used to predict the effects of changing lubrication oil of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with lower viscosity lubrication oils. Test oil LEF-H (20W) resulted in a ∼ 1.9% improvement in mechanical efficiency (ηmech) and a ∼ 16.5% reduction in FMEP vs. a commercial reference 40W oil. This improvement is a significant step in reaching the ARES goals.

Friction Reduction via Piston and Ring Design for an Advanced Natural-Gas Reciprocating Engine

2004 ◽  
Author(s):  
Grant Smedley ◽  
S. H. Mansouri ◽  
Tian Tian ◽  
Victor W. Wong
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Substantial Reduction ◽  
Friction Reduction ◽  
Design Parameters ◽  
Design Strategies ◽  
Low Friction ◽  
Piston Skirt ◽  
Model Predictions

Friction from the power cylinder represents a significant contribution to the total mechanical losses in internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel consumption, and reduced emissions. In this study, models incorporating piston ring dynamics and piston secondary motion with elastic skirt deformation were applied to a Waukesha natural gas power generation engine to identify the main contributors to friction within the piston and ring pack system. Based on model predictions, specific areas for friction reduction were targeted and low-friction design strategies were devised. The most significant contributors to friction were identified as the top ring, the oil control ring, and the piston skirt. Model predictions indicated that the top ring friction could be reduced by implementing a skewed barrel profile design or an upward piston groove tilt design, and oil control ring friction could be reduced by decreasing ring tension. Piston design parameters such as skirt profile, piston-to-liner clearance, and piston surface characteristics were found to have significant potential for the reduction of piston skirt friction. Designs were also developed to mitigate any adverse effects that were predicted to occur as a result of implementation of the low-friction design strategies. Specifically, an increase in wear was predicted to occur with the upward piston groove tilt design, which was eliminated by the introduction of a positive static twist on the top ring. The increase in oil consumption resulting form the reduction in the oil control ring tension was mitigated by the introduction of a negative static twist on the second ring. Overall, the low-friction design strategies were predicted to have potential to reduce piston ring friction by 35% and piston friction by up to 50%. This would translate to an improvement in brake thermal efficiency of up to 2%, which would result in a significant improvement in fuel economy and a substantial reduction in emissions over the life of the engine.

Mapping the MIT Campus in Real Time Using WiFi

2011 ◽  
pp. 326-338 ◽  
Author(s):  
Andres Sevtsuk
Keyword(s):  
Real Time ◽  
Ieee 802.11 ◽  
Academic Community ◽  
Internet Service Provider ◽  
Massachusetts Institute ◽  
Massachusetts Institute Of Technology ◽  
Test Bed ◽  
Internet Service ◽  
Log Files ◽  
Institute Of Technology

This chapter presents the iSPOTS project, which collects and maps data of WiFi usage on the Massachusetts Institute of Technology campus in Cambridge, Boston. Instead of simply mapping the locations of WiFi availability, the project is possibly the first to use and analyze log files from the Institute’s Internet service provider and to produce spatial visualizations of the observed activity in real time. The aim is to create a better understanding of the daily working and living patterns of the MIT academic community, which changes due to the emergence of WiFi itself. The MIT wireless IEEE 802.11 network, consisting of 3,000 access points (one of the largest of its kind) offers a privileged environment for this research and, in perspective, can provide a test bed for entire cities.

scholarly journals The ECPC Coupled Prediction Model

2008 ◽  
Vol 136 (1) ◽  
pp. 295-316 ◽  
Author(s):  
E. Yulaeva ◽  
M. Kanamitsu ◽  
J. Roads
Keyword(s):  
Prediction Model ◽  
Internal Variability ◽  
Reanalysis Data ◽  
Ocean Model ◽  
Department Of Energy ◽  
Massachusetts Institute Of Technology ◽  
Seasonal Forecasts ◽  
Coupled Models ◽  
Global Spectral Model ◽  
Institute Of Technology

Abstract This paper presents a new Experimental Climate Prediction Center (ECPC) Coupled Prediction Model (ECPM). The ECPM includes the Jet Propulsion Laboratory (JPL) version of the Massachusetts Institute of Technology (MIT) ocean model coupled to the ECPC version of the National Centers for Environmental Prediction (NCEP) Atmospheric Global Spectral Model (GSM). The adjoint and forward versions of the MIT model forced with the NCEP atmospheric analyses are routinely used at JPL for ocean state assimilation. An earlier version of the GSM was used for the NCEP–Department of Energy reanalysis-2 project and for operational seasonal forecasts at NCEP. The ECPM climatology and internal variability derived from a 56-yr-long coupled integration are compared with the observations and reanalysis data. Though the ECPM exhibits climatological biases, these biases are relatively small and comparable to the systematic errors produced by other well-known coupled models, including the recent NCEP Climate Forecast System. The internal variability of the model resembles the observations. ECPM simulates both seasonal and interannual variability in the tropical Pacific reasonably well. The model has good skill in reproducing the mechanism of ENSO evolution as well as ENSO teleconnection patterns (including the Indian monsoon–ENSO relationship). The skill of the ECPM in predicting 1994–2006 SST anomalies over the Niño-3.4 region is shown to be comparable to other coupled models. These retrospective forecasts were used for deriving a model climatology for real-time seasonal forecasts that are currently produced and displayed at ECPC.

Applying the Anderson-Darling Test to Suicide Clusters

Crisis ◽  
2013 ◽  
Vol 34 (6) ◽  
pp. 434-437 ◽  
Author(s):  
Donald W. MacKenzie
Keyword(s):  
Poisson Process ◽  
Goodness Of Fit ◽  
Small Samples ◽  
Massachusetts Institute Of Technology ◽  
Homogeneous Poisson Process ◽  
Cornell University ◽  
The Difference ◽  
Suicide Clusters ◽  
Institute Of Technology ◽  
Anderson Darling

Background: Suicide clusters at Cornell University and the Massachusetts Institute of Technology (MIT) prompted popular and expert speculation of suicide contagion. However, some clustering is to be expected in any random process. Aim: This work tested whether suicide clusters at these two universities differed significantly from those expected under a homogeneous Poisson process, in which suicides occur randomly and independently of one another. Method: Suicide dates were collected for MIT and Cornell for 1990–2012. The Anderson-Darling statistic was used to test the goodness-of-fit of the intervals between suicides to distribution expected under the Poisson process. Results: Suicides at MIT were consistent with the homogeneous Poisson process, while those at Cornell showed clustering inconsistent with such a process (p = .05). Conclusions: The Anderson-Darling test provides a statistically powerful means to identify suicide clustering in small samples. Practitioners can use this method to test for clustering in relevant communities. The difference in clustering behavior between the two institutions suggests that more institutions should be studied to determine the prevalence of suicide clustering in universities and its causes.

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