scholarly journals Non-Newtonian mixed thermo-elastohydrodynamics of hypoid gear pairs

2017 ◽  
Vol 232 (9) ◽  
pp. 1105-1125 ◽  
Author(s):  
M Mohammadpour ◽  
S Theodossiades ◽  
H Rahnejat ◽  
D Dowson
Keyword(s):  
Fuel Efficiency ◽  
Transmission Efficiency ◽  
Operating Conditions ◽  
Predictive Analysis ◽  
Hypoid Gear ◽  
Shear Rates ◽  
Contact Loads ◽  
Harmful Emissions ◽  
Vehicle Fuel Efficiency ◽  
Hypoid Gear Pairs

Transmission efficiency is the main objective in the development of vehicular differential systems, comprising hypoid gear pairs. The overall aim is to contribute to improved vehicle fuel efficiency and thus levels of harmful emissions for modern desired eco-drive axles. Detailed predictive analysis plays an important role in this quest, particularly under realistic operating conditions, comprising high contact loads and shear rates. Under these conditions, the hypoid gear pairs are subject to mixed non-Newtonian thermo-elastohydrodynamic conditions, which is the approach undertaken in this paper. Such an approach for hypoid gear pair has not hitherto been reported in the literature.

scholarly journals Multiphysics Investigations on the Dynamics of Differential Hypoid Gears

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
M. Mohammadpour ◽  
S. Theodossiades ◽  
H. Rahnejat
Keyword(s):  
Multiscale Analysis ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Transmission Efficiency ◽  
Operating Conditions ◽  
Hypoid Gear ◽  
Tooth Contact Analysis ◽  
Hypoid Gears ◽  
Gear Teeth ◽  
Noise Vibration

Vehicular differential hypoid gears play an important role on the noise, vibration, and harshness (NVH) signature of the drivetrain system. Additionally, the generated friction between their mating teeth flanks under varying load-speed conditions is a source of power loss in a drivetrain while absorbing some of the vibration energy. This paper deals with the coupling between system dynamics and analytical tribology in multiphysics, multiscale analysis. Elastohydrodynamic lubrication (EHL) of elliptical point contact of partially conforming hypoid gear teeth pairs with non-Newtonian thermal shear of a thin lubricant film is considered, including boundary friction as the result of asperity interactions on the contiguous surfaces. Tooth contact analysis (TCA) has been used to obtain the input data required for such an analysis. The dynamic behavior and frictional losses of a differential hypoid gear pair under realistic operating conditions are therefore determined. The detailed analysis shows a strong link between NVH refinement and transmission efficiency, a finding not hitherto reported in literature.

Prediction of friction-related power losses of hypoid gear pairs

2007 ◽  
Vol 221 (3) ◽  
pp. 387-400 ◽  
Author(s):  
H Xu ◽  
A Kahraman
Keyword(s):  
Friction Coefficient ◽  
Linear Regression Analysis ◽  
Mechanical Efficiency ◽  
Friction Model ◽  
Operating Conditions ◽  
Hypoid Gear ◽  
Power Losses ◽  
Efficiency Losses ◽  
Gear Contact ◽  
Hypoid Gear Pairs

A model to predict friction-related mechanical efficiency losses of hypoid gear pairs is proposed in this study. The model includes a gear contact model, a friction prediction model, and a mechanical efficiency formulation. The friction model uses a friction coefficient formula obtained by applying multiple linear regression analysis to a large number of elastohydrodynamic lubrication analyses covering typical ranges of key parameters associated with surface roughness, geometry, load, kinematics, and the lubricant. Formulations regarding the kinematic and geometric properties of the hypoid gear contact are presented. The load and friction coefficient distribution predictions are used to compute instantaneous torque/power losses and the mechanical efficiency of a hypoid gear pair at any given position. Results of a parametric study are presented at the end to highlight the influence of key operating conditions, surface finish, and lubricant properties on mechanical efficiency losses of hypoid gears.

scholarly journals Common Properties of Lubricants that Affect Vehicle Fuel Efficiency: A North American Historical Perspective

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 68 ◽  
Author(s):  
Mark Devlin
Keyword(s):  
Fuel Economy ◽  
Historical Perspective ◽  
Applied Research ◽  
Fuel Efficiency ◽  
Operating Conditions ◽  
Historical Research ◽  
System Level ◽  
Frictional Properties ◽  
Advanced Fuel ◽  
Vehicle Fuel Efficiency

The development of advanced lubricants to improve vehicle fuel efficiency can appear to be as simple as lowering the viscosity and frictional properties of a fluid. However, applied research studies have shown that it is quite difficult to quantify the fuel efficiency properties of advanced lubricants in vehicles. A review of the historical research predominantly performed in North America in this area reveals that there are many factors to consider in order to demonstrate the effectiveness of advanced lubricants. First, the methodology used to measure vehicle fuel efficiency will impact the results since there are many factors not related to the lubricant which will influence vehicle fuel efficiency. Second, developing advanced fuel-efficient lubricants under well controlled conditions overlooks the issue that lubricant properties such as viscosity and friction affect the operating conditions encountered by the lubricant in the vehicle. Finally, the physical properties of lubricants that historically control fuel economy do not have the same effect on fuel efficiency in all vehicles. The proper vehicle or system level test needs to be selected to properly assess the benefits of new advanced lubricants.

Demonstration of the Benefits of SAE 30 Stationary Gas Engine Oil in Full Scale Engine Tests

2021 ◽  
Author(s):  
Thijs Schasfoort ◽  
Zoe Fard ◽  
Torsten Gehrmann ◽  
Steffen Hollatz
Keyword(s):  
Positive Impact ◽  
Fuel Efficiency ◽  
Test Methods ◽  
Operating Conditions ◽  
Engine Oil ◽  
Gas Engine ◽  
Fuel Consumption Rate ◽  
Efficiency Performance ◽  
Endurance Testing ◽  
Efficiency Test

Abstract This paper evaluates the benefits of an SAE 30 monograde stationary gas engine oil (SGEO) in comparison with SAE 40 monograde SGEOs with the focus on two main areas. First, to demonstrate and quantify the positive impact of lower viscosity on the fuel consumption rate, and second to demonstrate the faster lubrication of hard to reach points in the engine during startup. The current industry recognized fuel efficiency test methods for passenger car and on-road diesel engine sectors are not suitable for evaluating the fuel efficiency performance of a gas engine oil because of the significant differences in fuel type, engine operating conditions, and oil formulations. This paper, therefore, describes comparative studies of three different gas engine oils in a modern MAN E3262 E302 gas engine that was carefully adapted and fully instrumented. The performance of each oil with respect to fuel efficiency was assessed in an extensive program comprising endurance testing, stationary tests on various load/speed points and dynamic tests running the engine fired as well as non-fired (motored). Another part of the test program explores the lubrication of hard to reach points in the engine, e.g. valve guide. The paper describes how the SAE 30 monograde oil results in faster lubrication of these parts during startup in comparison with the SAE 40 oils.

Contextual Density and US Automotive CO2 Emissions across the Rural–Urban Continuum

2015 ◽  
Vol 40 (6) ◽  
pp. 590-615 ◽  
Author(s):  
Andrew Perumal ◽  
David Timmons
Keyword(s):  
Urban Areas ◽  
Methodological Approach ◽  
Fuel Efficiency ◽  
Geographical Information ◽  
Population Densities ◽  
Spatial Differences ◽  
Using Data ◽  
Household Travel ◽  
Vehicle Fuel Efficiency ◽  
National Household Travel Survey

Using data from the 2009 National Household Travel Survey, we quantify the effects of settlement patterns on individual driving habits and the resulting automotive carbon dioxide (CO2) emissions. We employ CO2 emissions to capture this impact accurately, as it reflects both vehicle miles traveled and any spatial differences in vehicle fuel efficiency choices. While previous studies have compared automotive travel in urban and suburban areas, our approach characterizes emissions across the entire US rural–urban gradient, focusing on the effects of population density. Rather than using categorical measures of contextual density (city, suburb, town, etc.), we use a geographical information system to calculate continuous measures of contextual density, that is, density at different proximities to households. These measures of contextual density allow us to model travel effects induced by the gravitational pull of the population densities of urban cores. Further, our methodological approach frames location choice as an endogenous treatment effect; that is, residential locations are not randomly assigned across our sample and significantly alter driving behavior. We find that individuals living in urban cores generate the lowest per capita automotive CO2 emissions, due to close proximities of population concentrations. Rather than attracting individuals who would likely have low CO2 emissions anyway, urban location apparently mitigates the emissions of people who would otherwise tend to have high automotive CO2 emissions. We find larger elasticities with respect to density than previous studies and also find that the attractive forces of population densities affect driving patterns at distances up to sixty-one kilometers outside of urban areas.

scholarly journals Enhancement of Road Freight Vehicle Fuel Efficiency Using Lightweight Flat-Bed Trailers Made of High-Strength Steel Plates

2015 ◽  
Vol 22 (2) ◽  
pp. 65-82 ◽  
Author(s):  
Hong-Seung Roh ◽  
민연주 ◽  
장소영 ◽  
신승진 ◽  
YU, Byeong-Jae ◽  
...  
Keyword(s):  
High Strength Steel ◽  
Fuel Efficiency ◽  
High Strength ◽  
Steel Plates ◽  
Road Freight ◽  
Vehicle Fuel Efficiency

Fluid Dynamic Analysis of the 50 cc Penn State Artificial Heart Under Physiological Operating Conditions Using Particle Image Velocimetry

2004 ◽  
Vol 126 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Pramote Hochareon ◽  
Keefe B. Manning ◽  
Arnold A. Fontaine ◽  
John M. Tarbell ◽  
Steven Deutsch
Keyword(s):  
Particle Image Velocimetry ◽  
Artificial Heart ◽  
Particle Image ◽  
Flow Fields ◽  
Design Tool ◽  
Operating Conditions ◽  
Shear Rates ◽  
Heart Chamber ◽  
Image Velocimetry ◽  
Penn State

In order to bridge the gap of existing artificial heart technology to the diverse needs of the patient population, we have been investigating the viability of a scaled-down design of the current 70 cc Penn State artificial heart. The issues of clot formation and hemolysis may become magnified within a 50 cc chamber compared to the existing 70 cc one. Particle image velocimetry (PIV) was employed to map the entire 50 cc Penn State artificial heart chamber. Flow fields constructed from PIV data indicate a rotational flow pattern that provides washout during diastole. In addition, shear rate maps were constructed for the inner walls of the heart chamber. The lateral walls of the mitral and aortic ports experience high shear rates while the upper and bottom walls undergo low shear rates, with sufficiently long exposure times to potentially induce platelet activation or thrombus formation. In this study, we have demonstrated that PIV may adequately map the flow fields accurately in a reasonable amount of time. Therefore, the potential exists of employing PIV as a design tool.

Analysis of Throttle Opening Variation Impact on a Diesel Engine Performance Using Second Law of Thermodynamics

2009 ◽  
Author(s):  
B. B. Sahoo ◽  
U. K. Saha ◽  
N. Sahoo ◽  
P. Prusty
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Second Law Of Thermodynamics ◽  
Operating Conditions ◽  
Second Law ◽  
Engine Fuel ◽  
Availability Analysis ◽  
Second Law Analysis

The fuel efficiency of a modern diesel engine has decreased due to the recent revisions to emission standards. For an engine fuel economy, the engine speed is to be optimum for an exact throttle opening (TO) position. This work presents an analysis of throttle opening variation impact on a multi-cylinder, direct injection diesel engine with the aid of Second Law of thermodynamics. For this purpose, the engine is run for different throttle openings with several load and speed variations. At a steady engine loading condition, variation in the throttle openings has resulted in different engine speeds. The Second Law analysis, also called ‘Exergy’ analysis, is performed for these different engine speeds at their throttle positions. The Second Law analysis includes brake work, coolant heat transfer, exhaust losses, exergy efficiency, and airfuel ratio. The availability analysis is performed for 70%, 80%, and 90% loads of engine maximum power condition with 50%, 75%, and 100% TO variations. The data are recorded using a computerized engine test unit. Results indicate that the optimum engine operating conditions for 70%, 80% and 90% engine loads are 2000 rpm at 50% TO, 2300 rpm at 75% TO and 3250 rpm at 100% TO respectively.

Gasoline price and new vehicle fuel efficiency: Evidence from Canada

2017 ◽  
Vol 68 ◽  
pp. 454-465 ◽  
Author(s):  
Nicholas Rivers ◽  
Brandon Schaufele
Keyword(s):  
Fuel Efficiency ◽  
Gasoline Price ◽  
Vehicle Fuel Efficiency
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