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Hyunsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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Optimal Line Pressure Control for an Automatic Transmission-Based Parallel Hybrid Electric Vehicle considering Mode Change and Gear Shift:
Advances in Mechanical Engineering, 2014Co-Authors: Minseok Song, Seokhwan Choi, Youngchul Kim, Hyunsoo KimAbstract:An optimal Line Pressure control algorithm was proposed for the fuel economy improvement of an AT-based parallel hybrid electric vehicle (HEV). By performing lever analysis at each gear step, the required Line Pressure was obtained considering the torque ratio of the friction elements. In addition, the required Line Pressure of the mode clutch was calculated. Based on these results, the optimal Line Pressure map at each gear step of the EV and HEV modes was presented. Using the Line Pressure map, an optimal Line Pressure was performed for the AT input torque and mode. To investigate the proposed Line Pressure control algorithm, a HEV performance simulator was developed based on the powertrain model of the target HEV, and fuel economy improvement was evaluated. Simulation results showed that as the gear step became higher, the optimal Line Pressure control could reduce the hydraulic power loss, which gave a 2.2% fuel economy improvement compared to the existing Line Pressure control for the FTP-72 mode.
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development of an electric oil pump control algorithm for an automatic transmission based hybrid electric vehicle considering the gear shift characteristics
Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2014Co-Authors: Minseok Song, Youngchul Kim, Yeon Ho Kim, Jonghyu Kim, Hyunsoo KimAbstract:In this paper, an electric oil pump control algorithm for an automatic-transmission-based hybrid electric vehicle was proposed. Dynamic models of the hybrid electric vehicle powertrain and hydraulic control system, including a mechanical oil pump and an electric oil pump, were obtained, and a hybrid electric vehicle performance simulator was developed. Also, a flow consumption model of the hydraulic control system was constructed. To represent the characteristics of the hydraulic control system according to the change in the temperature of the automatic transmission fluid, a viscosity index concept was introduced. Based on the simulation and test results, a viscosity index–Line Pressure–electric oil pump power map was proposed to describe the power supply requirement according to the viscosity index and the required Line Pressure. Using the viscosity index–Line Pressure–electric oil pump power map, an electric oil pump control algorithm was suggested to control the electric oil pump by using multi-stage power for a given viscosity index. The mechanical oil pump speed at which the electric oil pump is turned off was obtained on the basis of the flow consumption model. The electric oil pump control algorithm was evaluated by experiments and simulations. The proposed electric oil pump control algorithm satisfied the target Line Pressure requirement according to the viscosity index. In addition, an electric oil pump control strategy during an automatic transmission gear shift was suggested for the situation in which the maximum Line Pressure required for the gear shift cannot be achieved by only the mechanical oil pump. The electric-oil-pump-assisted power was determined from the flow consumption model and the mechanical oil pump speed considering the gear shift. The simulation results confirmed that the electric oil pump control strategy satisfied the maximum Line Pressure during a gear shift.
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Power-based control of an electric oil pump for an automatic-transmission-based hybrid electric vehicle
Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2012Co-Authors: Yeon Ho Kim, Minseok Song, Jong-hyun Kim, Haksung Lee, Hyunsoo KimAbstract:A power-based control algorithm for an electric oil pump for a six-speed automatic-transmission-based hybrid electric vehicle was proposed. The new technology estimates the viscosity factor without having to measure the temperature of the automatic transmission fluid and controls the electric oil pump based on the required power. The viscosity factor was determined on a three-dimensional (3D) map by measuring the steady-state Line Pressure and the power and speed of the electric oil pump. Using the viscosity factor, the electric oil pump was controlled to supply the target Line Pressure according to the command power that was determined from the 3D viscosity factor-Line Pressure-power map. To save energy, multi-stage control was suggested which was based on low power, high power and medium power, according to the driving conditions of the vehicle. The test results showed that the proposed control method based on the electric oil pump power properly followed the target Line Pressure regardless of the change in the temperature of the automatic transmission fluid. In addition, when the Line Pressure changed owing to the additional flow rate consumption, e.g. during engine clutch engagement, the power-based control method easily followed the Line Pressure using only the target power, without needing to set the driving speed of the electric oil pump for each temperature. It was also found that control based on the electric oil pump power could save the driving power of the electric oil pump, unlike the situation with speed-based control, considering the product deviations.
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optimal engine operation by shift speed control of a cvt
Ksme International Journal, 2002Co-Authors: H Lee, Hyunsoo KimAbstract:In this paper, an algorithm to increase the shift speed is suggested by increasing the Line Pressure for a metal belt CVT. In order to control the shift speed, an algorithm to calculate the target shift speed is presented from the modified CVT shift dynamics. In applying the shift speed control algorithm, a criterion is proposed to prevent the excessive hydraulic loss due to the increased Line Pressure. Simulations are performed based on the dynamic models of the hydraulic control valves, powertrain and the vehicle. It is found from the simulation results that performance of the engine operation can be improved by the faster shift speed, which results in the improved fuel economy by 2% compared with that of the conventional electronic control CVT in spite of the increased hydraulic loss due to the increased Line Pressure.
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Shift speed improvement of a metal belt CVT
KSME International Journal, 2001Co-Authors: H Lee, Hyunsoo KimAbstract:This paper presents a CVT Line Pressure control strategy for the increased shift speed. Firstly, an algorithm to increase the CVT shift speed is suggested based on a modified CVT shift dynamics and shift speed maps are constructed. In addition, simplified dynamic models of the Line Pressure and the ratio control valve are derived by considering the CVT shift dynamics, and low level control algorithms for the ratio and the Line Pressure control are proposed. Using the shift speed maps and the simplified dynamic models of the CVT system, shift performance is investigated. It is found from the experimental and simulation results that improved shift speed can be achieved by increasing the Line Pressure.
T.c Eisele - One of the best experts on this subject based on the ideXlab platform.
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An on-Line Pressure vessel rheometer for slurries
Powder Technology, 1999Co-Authors: S. K. Kawatra, A. K. Bakshi, T.c EiseleAbstract:Abstract An on-Line rheometer, suitable for use with slurries, has been developed at Michigan Technological University. This rheometer can be used with both Newtonian and non-Newtonian slurries, and produces complete shear rate/shear stress curves which characterize the time-independent rheology of the slurry. The sensor utilizes the Hagen–Poiseuille equation and Boyle's law to calculate the shear rate, slurry flow rate, and shear stress from a series of Pressure measurements. The design of the unit allows the measurement sample to be continuously collected from operating process streams in the often-hostile on-Line environment. The shear rate/shear stress curves can be used to conveniently calculate the apparent viscosity at any given shear rate, and also to measure any yield stress or other deviations from Newtonian behavior.
S. K. Kawatra - One of the best experts on this subject based on the ideXlab platform.
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The On-Line Pressure Vessel Rheometer for Concentrated Coal Slurries
Coal Preparation, 2002Co-Authors: S. K. Kawatra, A. K. BakshiAbstract:At present, there are no commercially available rheometers that can make on-Line measurements of the rheological types of settling particulate slurries. To accomplish this measurement, a Pressure vessel rheometer has been developed for on-Line rheological measurements of concentrated suspensions. This rheometer is simple in construction and uses standard Pressure transducers and flow valves to make all necessary measurements of slurry flow through a calibrated tube. This simple design is made possible by the use of a sealed vessel to receive the slurry sample, which provides a means both for measuring the flowrate by monitoring the Pressure and for smoothly varying the flowrate so that a complete rheological curve can be determined. Using this instrument, flow curves of two different coal slurries were determined. The first coal slurry sample consisted of coal ground to pass 106 µm and was suspended at a concentration of 52 wt % solids. The second sample consisted of coal ground to pass 850 µm, and was su...
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An on-Line Pressure vessel rheometer for slurries
Powder Technology, 1999Co-Authors: S. K. Kawatra, A. K. Bakshi, T.c EiseleAbstract:Abstract An on-Line rheometer, suitable for use with slurries, has been developed at Michigan Technological University. This rheometer can be used with both Newtonian and non-Newtonian slurries, and produces complete shear rate/shear stress curves which characterize the time-independent rheology of the slurry. The sensor utilizes the Hagen–Poiseuille equation and Boyle's law to calculate the shear rate, slurry flow rate, and shear stress from a series of Pressure measurements. The design of the unit allows the measurement sample to be continuously collected from operating process streams in the often-hostile on-Line environment. The shear rate/shear stress curves can be used to conveniently calculate the apparent viscosity at any given shear rate, and also to measure any yield stress or other deviations from Newtonian behavior.
Sumio Hoka - One of the best experts on this subject based on the ideXlab platform.
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In-Line Pressure within a HOTLine^® Fluid Warmer, under various flow conditions
Journal of Clinical Monitoring and Computing, 2015Co-Authors: Midoriko Higashi, Ken Yamaura, Yukie Matsubara, Takuya Fukudome, Sumio HokaAbstract:Roller pump infusion devices are widely used for rapid infusion, and may be combined with separate warming devices. There may be instances however, where the Pressures generated by the roller pump may not be compatible with the warming device. We assessed a commonly used roller pump in combination with a HOTLine^® Fluid Warmer, and found that it could generate Pressures exceeding the HOTLine^® manufacturers specifications. This was of concern because the HOTLine^® manufacturer guideLine states that not for use with Pressure devices generating over 300 mmHg. Pressure greater than 300 mmHg may compromise the integrity of the HOTLine^® Fluid Warming Set. The aim of this study was to compare in-Line Pressure within a HOTLine^® Fluid Warmer at different infusion rates of a roller pump using various sizes of intravenous cannulae. The rapid infusion system comprised a 500 mL-normal saLine bag, roller pump type infusion device, HOTLine^® Fluid Warmer (blood and fluid warmer system), and six different sizes of intravenous cannulae. In-Line Pressure was measured proximal to the HOTLine^® (pre-warmer) and proximal to the cannula (post-warmer), at flow rate of 50–160 mL/min. The in-Line Pressures increased significantly with increasing flow rate. The pre-warmer Pressures exceeded 300 mmHg when the flow rate was ≥120 mL/min with 20-gauge, 48 mm length cannula, 130 with 20-gauge, 25 mm cannula, and 160 mL/min with 18-gauge, 48 mm cannula. However, they were
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in Line Pressure within a hotLine fluid warmer under various flow conditions
Journal of Clinical Monitoring and Computing, 2015Co-Authors: Midoriko Higashi, Ken Yamaura, Yukie Matsubara, Takuya Fukudome, Sumio HokaAbstract:Roller pump infusion devices are widely used for rapid infusion, and may be combined with separate warming devices. There may be instances however, where the Pressures generated by the roller pump may not be compatible with the warming device. We assessed a commonly used roller pump in combination with a HOTLine® Fluid Warmer, and found that it could generate Pressures exceeding the HOTLine® manufacturers specifications. This was of concern because the HOTLine® manufacturer guideLine states that not for use with Pressure devices generating over 300 mmHg. Pressure greater than 300 mmHg may compromise the integrity of the HOTLine® Fluid Warming Set. The aim of this study was to compare in-Line Pressure within a HOTLine® Fluid Warmer at different infusion rates of a roller pump using various sizes of intravenous cannulae. The rapid infusion system comprised a 500 mL-normal saLine bag, roller pump type infusion device, HOTLine® Fluid Warmer (blood and fluid warmer system), and six different sizes of intravenous cannulae. In-Line Pressure was measured proximal to the HOTLine® (pre-warmer) and proximal to the cannula (post-warmer), at flow rate of 50-160 mL/min. The in-Line Pressures increased significantly with increasing flow rate. The pre-warmer Pressures exceeded 300 mmHg when the flow rate was ≥120 mL/min with 20-gauge, 48 mm length cannula, 130 with 20-gauge, 25 mm cannula, and 160 mL/min with 18-gauge, 48 mm cannula. However, they were <300 mmHg at any flow rates with 18-gauge, 30 mm cannula and 16-gauge cannulae. The post-warmer Pressures exceeded 300 mmHg at the flow rate of 140 mL/min with 20-gauge, 48 mm cannula, and 160 mL/min with 20-gauge, 25 mm cannula, while they were <300 mmHg at any flow rates with 18 and 16-gauge cannulae. The in-Line Pressure within a HOTLine® could exceed 300 mmHg, depending on the flow rate and size and length of cannula. It is important to pay attention to the size and length of cannulae and flow rate to keep the maximum in-Line Pressure<300 mmHg when a roller pump type infusion device is used.
Patrick W. Weerwind - One of the best experts on this subject based on the ideXlab platform.
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A volume buffer capacity device dynamically reduces excessive venous Line Pressure and arterial gaseous embolic load during minimized cardiopulmonary bypass
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 2014Co-Authors: Antoine P. Simons, Patrick W. WeerwindAbstract:In the January 2014 issue of the journal, we read the interesting article of Aboud et al., in which they describe a comparison of miniaturized versus conventional open cardiopulmonary bypass regarding venous Line Pressure, gaseous microemboli (GME), biochemical parameters of systemic inflammatory response, ischaemia, haemodilution and haemolysis [1]. Among other findings, they found predominantly long-lasting and severely low Pressures in the venous Line and right atrium, as well as a significantly higher GME activity in the miniaturized cardiopulmonary bypass group. Furthermore, they found low venous Line Pressure to be accompanied by arterial and venous air bubbles >500 μm in diameter. A comparable study previously published by our group comparing standard closed cardiopulmonary bypass with two different types of miniaturized circuits showed similar results [2]. Although we could not trace such large arterial air bubbles as Aboud et al. did, we found excessive subatmospheric drainage Pressures to significantly correlate with arterial GME activity (Pearson’s correlation factor −0.35), whereas bubble activity proved near-absent in the group using the standard closed circuit. Moreover, in some cases, we found arterial cumulative GME volume to be larger than venous volume and hypothesized de novo microbubble formation induced by in-pump degassing to be the cause of the increase in GME volume. This was confirmed in two sequential studies showing that impeded drainage resulted in arterial GME, while the venous Line was GME-free [3, 4]. We therefore emphasize that excessively low venous drainage Pressures should be prevented and that both miniaturized systems and managing those require further refinements. Aboud et al. mention distinctive sources for ‘in-circuit air’ that eventually lead to arterial GME. One is entrainment at the cannulation site, or as Zanatta et al. [5] showed, GME-contaminated fluids infused via a central venous Line. A combination of entrainment and infusion might explain the relatively high amount of venous and arterial GME >500 μm found by Aboud et al., although one would expect the oxygenator and arterial filter to eliminate such large bubbles. Another source of arterial GME can be degassing of blood-dissolved gasses inside the centrifugal pump, which occurs when venous Line Pressure peaks down to excessively low subatmospheric values during so-called ‘venous Line chattering’. In that context, a passive volume buffer capacity device (BigBetterBladder, Circulatory Technologies, Inc., Oyster Bay, NY, USA) inserted into the venous Line has shown to result in a 14% increase in average support, a 40% decrease in fluctuations of venous Line Pressure and an 85% reduction in GME [2, 4]. A volume buffer capacity device added to the venous Line in systems that directly drain from the right atrium should therefore be considered a mandatory rather than optional safety feature. We are grateful to Aboud et al. for sharing their experience and knowledge and for highlighting the fact that evident benefits of mini-perfusion systems do not come without consequences.
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Efficacy and safety of strategies to preserve stable extracorporeal life support flow during simulated hypovolemia.
Perfusion, 2013Co-Authors: Antoine P. Simons, A. A. M. A. Lindelauf, Yuri M. Ganushchak, Jos G. Maessen, Patrick W. WeerwindAbstract:AIM Without volume-buffering capacity in extracorporeal life support (ELS) systems, hypovolemia can acutely reduce support flow. This study aims at evaluating efficacy and safety of strategies for preserving stable ELS during hypovolemia. MATERIAL & METHODS Flow and/or Pressure-guided servo pump control, a reserve-driven control strategy and a volume buffer capacity (VBC) device were evaluated with respect to pump flow, venous Line Pressure and arterial gaseous microemboli (GME) during simulated normovolemia and hypovolemia. RESULTS Normovolemia resulted in a GME-free pump flow of 3.1 ± 0.0 L/min and a venous Line Pressure of -10 ± 1 mmHg. Hypovolemia without servo pump control resulted in a GME-loaded flow of 2.3 ± 0.4 L/min with a venous Line Pressure of -114 ± 52 mmHg. Servo control resulted in an unstable and GME-loaded flow of 1.5 ± 1.2 L/min. With and without servo pump control, the VBC device stabilised flow (SD = 0.2 and 0.0 L/min, respectively) and venous Line Pressure (SD=51 and 4 mmHg, respectively) with near-absent GME activity. Reserve-driven pump control combined with a VBC device restored a near GME-free flow of 2.7 ± 0.0 L/min with a venous Line Pressure of -9 ± 0 mmHg. CONCLUSION In contrast to a reserve-driven pump control strategy combined with a VBC device, flow and Pressure servo control for ELS show evident deficits in preserving stable and safe ELS flow during hypovolemia.
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hypovolemia in extracorporeal life support can lead to arterial gaseous microemboli
Artificial Organs, 2013Co-Authors: Antoine P. Simons, Yuri M. Ganushchak, Jos G. Maessen, Steven Teerenstra, Dennis C J J Bergmans, Patrick W. WeerwindAbstract:Next to severely decreased pump flow, hypovolemia in extracorporeal life support (ELS) can result in subatmospheric venous Line Pressure. Such Pressure may lead to degassing and resultant gaseous microemboli (GME), with potential changes in neurological clinical outcome. CME activity resulting from degassing was investigated in relation to subatmospheric venous Line Pressure, partial oxygen Pressure (pO ), and hematocrit in a model of a centrifugal pump-based circuit for long-term ELS. Additionally, a device that provides instantaneous volume buffer capacity during hypovolemia was evaluated in relation to GME appearance. An exponential relationship was found between decreasing venous Line Pressure and GME downstream of the centrifugal pump (P = 0.001). Arterial bubble activity appeared at subatmospheric venous Line Pressures of -200 mm Hg and less. A rising (pO ) increased formation of GME (P = 0.05). A rise in hematocrit, in contrast, did not affect embolic activity (P = 0.22). With simulated hypovolemia, volume buffer capacity added to the venous Line dampened fluctuations of venous Line Pressure by approximately 40%, but a significant reduction in GME formation could not be found (P = 0.22). Moreover, the device enabled a 14% higher support flow. With ELS flow being related to patient volume status, hypovolemia can diminish support. A coherent decrease of venous Line Pressure triggers degassing of blood-dissolved gases and causes arterial GME, which can become massive during persistent conditions of limited venous return. Incorporation of a volume buffer capacity device into the extracorporeal support circuit enables a higher and more stable support flow in critically low patient filling.