Discussion: “Modeling and Analysis of the Meshing Losses of Involute Spur Gears in High-Speed and High-Load Conditions” (Chang, L., Jeng, Y.-R., and Huang, P.-Y., 2013, J. Tribol., 135, p. 011504)

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Ph. Velex
Keyword(s):  
High Speed ◽  
High Load ◽  
Spur Gears ◽  
Modeling And Analysis ◽  
Load Conditions

Modeling and Analysis of the Meshing Losses of Involute Spur Gears in High-Speed and High-Load Conditions

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
L. Chang ◽  
Yeau-Ren Jeng ◽  
Pay-Yau Huang
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Load ◽  
Design Parameters ◽  
Physical Parameters ◽  
Spur Gears ◽  
Modeling And Analysis ◽  
Helical Gears ◽  
Viscosity Coefficients ◽  
Pressure Angle

A first-principle based mathematical model is developed in this paper to analyze the meshing losses in involute spur gears operating in high-load and high-speed conditions. The model is fundamentally simple with a few clearly defined physical parameters. It is computationally robust and produces meaningful trends and relative magnitudes of the meshing losses with respect to the variations of key gear and lubricant parameters. The model is evaluated with precision experimental data. It is then used to study the effects of various gear and lubricant parameters on the meshing losses including gear module, pressure angle, tooth addendum height, thermal conductivity, and lubricant pressure-viscosity and temperature-viscosity coefficients. The results and analysis suggest that gear module, pressure angle, and lubricant pressure-viscosity and temperature-viscosity coefficients can significantly affect the meshing losses. They should be the design parameters of interest to further improve the energy efficiency in high-performance, multistage transmission systems. Although the model is developed and results obtained for spur gears, the authors believe that the trends and relative magnitudes of the meshing losses with respect to the variations of the gear and lubricant parameters are still meaningful for helical gears.

A Virtual Tool for Wear Simulation of Standard and Non-Standard Spur Gears

2012 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire ◽  
E. Karpat
Keyword(s):  
High Speed ◽  
High Performance ◽  
Failure Modes ◽  
Power Transmission ◽  
Wear Behavior ◽  
Gear Tooth ◽  
Load Capacity ◽  
High Load ◽  
Wear Depth ◽  
Spur Gears

There is an industrial demand for the increased performance of mechanical power transmission devices. This need in high performance is driven by high load capacity, high endurance, low cost, long life, and high speed. New designs and modifications in gears have been investigated to obtain high load carrying capacity and increased life with less volume and weight. Tooth wear is one of the major failure modes in gears. Although there are different classifications of wear mechanisms, wear on gears can be simply classified as mild wear, pitting, and severe wear, depending on the wear rate. These types of wear may lead to power transmission losses, decreased efficiency, increased vibration and noise, and gear tooth failure. This paper deals with the simulation of wear for standard and non-standard gears using an analytical approach. A numerical model for wear prediction of gear pair is developed. A wear model based on Archard’s equation is employed to predict wear depth. A MATLAB-based virtual tool is developed to analyze wear behavior of standard and non-standard spur gears with various gear parameters. In this paper, this virtual tool is introduced by using many numerical examples.

Cause of Exhaust Smoke and Its Reduction Methods in an HSDI Diesel Engine Under High-Speed and High-Load Conditions

2002 ◽  
Author(s):  
Yoshihiro Hotta ◽  
Kiyomi Nakakita ◽  
Takayuki Fuyuto ◽  
Minaji Inayoshi ◽  
Kiyoshi Fujiwara ◽  
...  
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
High Load ◽  
Reduction Methods ◽  
Hsdi Diesel Engine ◽  
Load Conditions

scholarly journals Evaluation of exhaust gas recirculation techniques on a high-speed direct injection diesel engine using first law analysis

2018 ◽  
Vol 233 (3) ◽  
pp. 710-726 ◽  
Author(s):  
Nick Papaioannou ◽  
Felix CP Leach ◽  
Martin H Davy ◽  
Adam Weall ◽  
Brian Cooper
Keyword(s):  
High Speed ◽  
Direct Injection ◽  
Exhaust Gas Recirculation ◽  
High Load ◽  
Exhaust Gas ◽  
Indicated Mean Effective Pressure ◽  
Energy Flows ◽  
Baseline Case ◽  
Gas Recirculation ◽  
Load Conditions

The effects of different exhaust gas recirculation (EGR) strategies on engine efficiency and the resulting energy flows at two speed/load conditions (1500 r/min/6.8 bar net indicated mean effective pressure (nIMEP) and 1750 r/min/13.5 bar nIMEP) were studied using a first law analysis approach. The EGR strategies tested were as follows: cooled high-pressure exhaust gas recirculation (baseline), the application of exhaust gas recirculation with the swirl flap closed and the use of exhaust gas recirculation under constant λ conditions. The closed swirl flap exhaust gas recirculation strategy reduced brake efficiency under high load conditions and increased heat transfer to the coolant for both load cases. Soot and CO emissions increased at high load, however, with an increase in NOx relative to the baseline case. The constant λ exhaust gas recirculation strategy reduced brake efficiency under low load, as well as the heat flow to the coolant for both load cases. The constant λ exhaust gas recirculation strategy benefited smoke emissions and increased combustion exhaust gas recirculation tolerance, albeit with a penalty in NOx emission.

scholarly journals Spray characteristics of a fuel–water internally rapid mixing injector for burner combustion

2018 ◽  
Author(s):  
Y. Nada ◽  
Y. Kidoguchi ◽  
S. Yoshimura ◽  
K. Onoda ◽  
D. Asao ◽  
...  
Keyword(s):  
High Speed ◽  
Sampling Method ◽  
High Load ◽  
Soot Emission ◽  
Rapid Mixing ◽  
Fuel Droplets ◽  
Emulsified Fuel ◽  
Mixing Chamber ◽  
Atomization Characteristics ◽  
Load Conditions

The fuel-water internally rapid mixing type of injector has been developed to reduce NOx and soot emissions from combustion furnaces operating under high-load conditions. The injector allows spray injection of water emulsified fuel originating from base fuel and water without any surfactants. The aim of present study is to elucidate the mechanism of emulsification occurring in the injector and the atomization characteristics of the injector. We measured the sizes of fuel droplets discharged from the injector by means of a high-speed shadowgraph method combined with image processing. Soybean oil was used as the base fuel. The flow patterns of the fuel and water in a transparent mixing chamber of the injector were also visualized. In addition, we investigated the inner structure of the large droplets sampled by an immersion droplet sampling method. The base fuel, water and air are separately introduced into the injector. In the mixing chamber of the injector, fuel and water are blown by swirling air, and then impinge on the inner wall of the chamber. The base fuel is emulsified through the mixing of fuel with water resulting from the impingement. The emulsified fuel moves to injection holes along the inner wall, and is finally discharged through the injection holes with atomizing air. The probability profiles of droplet size exhibit that the existence probabilities of coarse droplets with diameters greater than approximately 35 mm are increased when the fuel is emulsified. Although the emulsification deteriorates the atomization capability of the injector, the secondary atomization including the micro-explosion occurring in combustion furnaces would form fine droplets, and thus reducing the soot emission from the furnaces. The microscope observations revealed that the emulsified fuel filling in a large droplet sampled corresponds to W/O type.

scholarly journals Utilizing One-Way Valve to Optimize Turbocharger Performance on a Blended EGR Engine

2021 ◽  
Vol 7 ◽  
Author(s):  
Gaurav Handa ◽  
Bradley Denton ◽  
Sankar Rengarajan ◽  
Christopher Chadwell ◽  
Graham Conway
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Load Condition ◽  
Exhaust Gas Recirculation ◽  
High Load ◽  
Exhaust Gas ◽  
Personal Transportation ◽  
Gas Recirculation ◽  
Load Conditions

Internal combustion engines will be a part of personal transportation for the foreseeable future. One recent trend for engines has been downsizing which enables the engine to run more favorably over regulatory drive cycles. Another shift due to downsizing is the increase in engine power density which leads to problems with engine knock. One way to reduce the knock propensity of engines is by introducing Exhaust Gas Recirculation (EGR) into the combustion chamber. Exhaust Gas Recirculation also helps improve fuel economy and can reduce NOX emissions. EGR reduces volumetric efficiency which places challenges on the boosting system. LP-EGR helps to lower backpressure and improves scavenging which helps reduce knock and operate at a high efficiency at the low-speed and high-load conditions. At high-speed, and high-load operation however, LP-EGR operation can choke the compressor. This would mean that the turbocharger would need resizing to allow a higher mass flow at these higher speed-load conditions. The HP-EGR helps by reducing the flow rates to the compressor at the higher speed-load conditions which avoids compressor choke and permits a full load performance while retaining a smaller, more transient capable turbocharger. The concept of a one-way valve in the HP-EGR Loop has been explored in this paper. During HP-EGR operation, pressure pulsations drive the intake air back through the HP-EGR Loop and limit the maximum amount of HP-EGR. A one-way valve would prevent any backflow and permit a greater HP-EGR flow for a given average delta pressure. For a given EGR rate, this enables a wider throttle position and thus better controllability at the higher speed-load conditions. Engine testing with the one-way valve suggested that the HP-EGR rate at the high speed/load condition was nearly doubled while reducing the PMEP with an improvement in the Brake Specific Fuel Consumption . Additionally, this led to more reasonable actuator positions in terms of the EGR valve and the intake throttle to ensure better controllability.

CYCLOPS BHT

Alloy Digest ◽  
1965 ◽  
Vol 14 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Elevated Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
High Strength ◽  
Heat Treating ◽  
High Load ◽  
Structural Components ◽  
Temperature Performance

Abstract Cyclops BHT is a low-alloy martensitic high-speed steel of the molybdenum type recommended for high strength, high load structural components designed for elevated temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-173. Producer or source: Cyclops Corporation.

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