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Cryogenic Cam Butterfly Valve

  • Magazine Article
  • TBMG-34596
Published 2019-06-01 by Tech Briefs Media Group in United States

Typical butterfly valves cannot seal at both ambient and cryogenic temperatures. At cryogenic temperatures, valves grow and shrink, changing critical dimensions such as distance between the disc and seat. Ideally, valves would compensate. The inability of existing butterfly valves to do this led to the design of the Cryogenic Cam Butterfly Valve (CCBV) in which the disc rides on a cam shaft and is held rigid by a torsion spring that provides both axial movement of the disc in addition to the standard 90-degree rotation of a standard butterfly valve. Because the valve’s disc can rotate and translate, it can hold a tighter seal, preventing leakage despite dimensional changes caused by changing operating temperatures.

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Videogrammetry in Vehicle Crash Reconstruction with a Moving Video Camera

Engineering Systems Inc.-Emmanuel Jay Manuel, Richard Mink
Engineering Systems, Inc.-Daniel Kruger
Published 2018-04-03 by SAE International in United States
In an accident reconstruction, vehicle speeds and positions are always of interest. When provided with scene photographs or fixed-location video surveillance footage of the crash itself, close-range photogrammetry methods can be useful in locating physical evidence and determining vehicle speeds and locations. Available 3D modeling software can be used to virtually match photographs or fixed-location video surveillance footage. Dash- or vehicle-mounted camera systems are increasingly being used in light vehicles, commercial vehicles and locomotives. Suppose video footage from a dash camera mounted to one of the vehicles involved in the accident is provided for an accident reconstruction but EDR data is unavailable for either of the vehicles involved. The literature to date describes using still photos to locate fixed objects, using video taken from stationary camera locations to determine the speed of moving objects or using video taken from a moving vehicle to locate fixed objects. However, techniques to evaluate the position, speed and acceleration of moving objects seen in video taken from moving locations have not been evaluated. To address the increasing prevalence of dash…
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Model Predictive Control of Turbocharged Gasoline Engines for Mass Production

General Motors LLC-Ruixing Long, Julian Verdejo
ODYS SRL-Alberto Bemporad, Daniele Bernardini
Published 2018-04-03 by SAE International in United States
This paper describes the design of a multivariable, constrained Model Predictive Control (MPC) system for torque tracking in turbocharged gasoline engines scheduled for production by General Motors starting in calendar year 2018. The control system has been conceived and co-developed by General Motors and ODYS. The control approach consists of a set of linear MPC controllers scheduled in real time based on engine operating conditions. For each MPC controller, a linear model is obtained by system identification with data collected from engines. The control system coordinates throttle, wastegate, intake and exhaust cams in real time to track a desired engine torque profile, based on measurements and estimates of engine torque and intake manifold pressure. The MPC optimizes torque tracking during both transient and steady-state operations, minimizing specific fuel consumption and taking into account predefined fuel-efficient steady-state actuators positions, as well as constraints on input and output variables. Actuator commands are computed by solving an optimization problem at each sampling instant. Each linear MPC controller is equipped with a Kalman filter to reconstruct the system state…
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Miniature Linear Bearings Help Prolong Curiosity’s Mars Mission

  • Magazine Article
  • TBMG-27943
Published 2017-12-01 by Tech Briefs Media Group in United States

The launch, landing, and overall mission of NASA’s Mars Science Laboratory (MSL) is arguably one of the most daring — and successful — space exploration endeavors ever undertaken. After a successful landing at Gale Crater on August 6, 2012, MSL’s Curiosity rover has already surpassed its 23-month mission target, and it continues to transmit informative images of the Martian surface on a daily basis.

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IAV brings variable valvetrains to heavy duty

SAE Truck & Off-Highway Engineering: December 2017

Bruce Morey
  • Magazine Article
  • 17TOFHP12_08
Published 2017-12-01 by SAE International in United States

Variable valve actuation, especially timing, has been readily available for light passenger engines for years. Problems in introducing the technology to heavy-duty diesel engines include the vastly different thermodynamics at play and the durability required. With already high compression ratios, clearance between the piston and valve in diesels can be an issue. Since a diesel is typically unthrottled, it is more difficult to improve efficiency compared to a gasoline engine. Constant switching in engines that run continuously means building reliable gadgets that can run for thousands of hours.

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A Comparative Study on Influence of EIVC and LIVC on Fuel Economy of A TGDI Engine Part I: Friction Torques of Intake Cams with Different Profiles and Lifts

Jiangling Motors Co., Ltd.-Xianlin Ouyang, Ho Teng, Xiaochun zeng, Xuwei Luo, Tingjun Hu, Xianlong Huang, Jiankun Luo, Yongli Zhou
Published 2017-10-08 by SAE International in United States
In order to better understand how the Atkinson cycle and the Miller cycle influence the fuel consumption at different engine speeds and loads, an investigation was conducted to compare influences of early intake valve closing (EIVC) and late intake valve closing (LIVC) on the fuel consumption of a 1.5L turbo-charged gasoline direct injection (TGDI) engine. The engine was tested with three different intake cams, covering three intake durations: 251 degCA (the base engine), 196 degCA (the Miller engine), and 274 degCA (the Atkinson engine). Compression ratios are 9.5:1 for the base engine and 11.4:1 for the Atkinson and Miller engines, achieved with piston modifications. Results of this investigation will be reported in three papers focusing respectively on characteristics of the engine friction, in-cylinder charge motions for different intake events, and combustion and fuel economy without and with EGR for the naturally aspirated mode and boost mode. The present paper is Part I of this investigation. This study reports the results of detailed analyses as well as experiments on characteristics of the cam dynamics and friction…
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Comparing the Effect of a Swirl Flap and Asymmetric Inlet Valve Opening on a Light Duty Diesel Engine

Jaguar Land Rover-Adam Weall, Brian Cooper
University of Oxford-Felix Leach, Martin Davy
Published 2017-10-08 by SAE International in United States
Diesel engine designers often use swirl flaps to increase air motion in cylinder at low engine speeds, where lower piston velocities reduce natural in-cylinder swirl. Such in-cylinder motion reduces smoke and CO emissions by improved fuel-air mixing. However, swirl flaps, acting like a throttle on a gasoline engine, create an additional pressure drop in the inlet manifold and thereby increase pumping work and fuel consumption. In addition, by increasing the fuel-air mixing in cylinder the combustion duration is shortened and the combustion temperature is increased; this has the effect of increasing NOx emissions. Typically, EGR rates are correspondingly increased to mitigate this effect. Late inlet valve closure, which reduces an engine’s effective compression ratio, has been shown to provide an alternative method of reducing NOx emissions. Recently introduced technologies combine these two effects by retarding only the swirl port valve, increasing in-cylinder swirl while simultaneously reducing the effective compression ratio.In this paper the effects of using a swirl flap and offset cams are compared. Four different swirl flap positions (ranging from fully open to fully…
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Energy Management Through Direct Drive Servo Technology

  • Magazine Article
  • TBMG-27268
Published 2017-08-01 by Tech Briefs Media Group in United States

Direct drive servo motor and drive technology has many advantages. It reduces an axis’ parts count, mechanical losses, and often its objectionable noise. What’s more, it also increases the machine’s efficiency, lowering operation cost for the user due to its inertia ratio as compared to the more common mechanically advantaged multi-body axis designs. Reducing the mechanical transmission components (gearboxes, timing belts, pulleys, cams, lead screws, etc.) between the motor and its load is only part of the savings.

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Nissan unveils variable-compression-ratio ICE for 2018 Infiniti production model

Automotive Engineering: November 3, 2016

John Kendall
  • Magazine Article
  • 16AUTP11_05
Published 2016-11-01 by SAE International in United States

Nissan broke new ground for gasoline engines at the 2016 Paris Motor Show when it unveiled the first production-intent variable-compression-ratio gasoline engine. The VC-Turbo, a 2.0-L inline four cylinder designed in house, features a novel cranktrain and control system that enables the effective compression ratio to be varied between 8.0:1 and 14:1, depending on load.

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Investigations on Ventilation Strategies for SI Cylinder Deactivation Based on a Variable Valve Train

IAV GmbH-Wolfram Gottschalk, Rene Fink, Matthias Schultalbers
Published 2016-10-17 by SAE International in United States
Advanced SI engines for passenger cars often use the cylinder deactivation technology for dethrottling and thus achieving a reduction of fuel consumption. The gas exchange valves of the deactivated cylinders are closed permanently by a zero lift of the cams. The solutions for cylinder deactivation can vary in the kind of gas composition included in the deactivated cylinders: charge air, exhaust gas or vacuum. All these strategies have in common the frequent loss of captured charge mass from cycle to cycle. Their two-stroke compression-expansion cycle additionally intensifies this phenomenon. Thus, a significant decrease of the minimum cylinder pressure can cause an undesired entry of lubricant into the combustion chamber. The idea was to ventilate the generally deactivated cylinders frequently to compensate the loss of captured cylinder charge mass. The task was to keep the minimum cylinder pressure above a certain limit to prevent the piston rings from a failure. However, a compromise has to be found about the value of IMEP the deactivated cylinders perform in dependence of the included charge mass. The experimental design…
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