Steady-State and Transient Operation Simulation of a “Downsized” Turbocharged SI Engine

2007 ◽  
Author(s):  
F. Bozza ◽  
A. Gimelli ◽  
L. Strazzullo ◽  
E. Torella ◽  
C. Cascone
Keyword(s):  
Steady State ◽  
Transient Operation ◽  
Si Engine

An Experimental and Numerical Study of the Steady-State Flow of a SI-Engine Intake Port

1998 ◽  
Author(s):  
H. Bensler ◽  
C. Freek ◽  
B. Beesten ◽  
A. Ritter ◽  
A. W. Hentschel
Keyword(s):  
Steady State ◽  
Numerical Study ◽  
Intake Port ◽  
Steady State Flow ◽  
Si Engine ◽  
State Flow

Fast-Tracking an FLNG Relocation in Malaysia

2021 ◽  
Vol 73 (04) ◽  
pp. 39-40
Author(s):  
Judy Feder
Keyword(s):  
Steady State ◽  
Cost Minimization ◽  
Flow Assurance ◽  
Transient Operation ◽  
Fast Tracking ◽  
Engineering Studies ◽  
Offshore Technology ◽  
State Study ◽  
Common Support ◽  
Minimal Modification

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper OTC 30440, “Floating LNG 1 Relocation: Another World’s First,” by Muhammad Fakhruddin Jais, Wan Mahsuri Wan Hashim, and Ariff Azhari Ayadali, Petronas, et al., prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, Malaysia, 17–19 August. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. Floating liquefied natural gas (FLNG) allows LNG to be processed hundreds of kilometers away from land to unlock gas reserves in remote and stranded fields previously uneconomical to monetize. The complete paper describes the operator’s fast-tracking of a 450-km FLNG unit relocation from Sarawak to Sabah offshore Malaysia. The time from selecting the new field to unloading LNG at the new location was 13 months. The complete paper discusses pre-execution and engineering studies, relocation preparation and execution, and challenges encountered, including timeline, cost minimization, and manning. Introduction Since 2016, Petronas has operated its first floating LNG production, storage, and offloading facility offshore Sarawak. During the tenure of operation, cargo was delivered successfully to customers worldwide. An opportunity to help a different gas supplier monetize another stranded field offshore Sabah, approximately 450 km away from the unit’s original location, presented itself. The new opportunity was deemed feasible for several reasons. - The identified location is still within Malaysian waters and thus is subject to similar authority and regulations. - Operation within the same country ensures common support from vendor and contractors to some extent. - The two fields have similar gas profiles and water depth. The project team determined that these factors would result in minimal modification at both FLNG and up-stream facilities to meet minimum shut-down from project sanction until first LNG cargo was produced. Pre-Execution and Engineering Studies To fast-track the project, an evaluation was conducted of the new feed-gas composition and modification of both up-stream and FLNG facilities. Long-lead items (LLIs) were identified, and studies were conducted to secure the items. One of the identified LLIs was the flexible pipeline from the upstream facilities to the FLNG. A flow-assurance study covered the steady-state and transient operation for the flexible line. This study confirmed the size of the pipeline and defined the functional requirement for the flexible pipeline procurement. Among the key parameters identified were the pipeline’s thermal conductivity and design pressure. During the feasibility stage, a steady-state study was conducted to determine the length of the flexible line in order to meet the landing pressure and temperature at the FLNG. Instead of requiring additional cooler, the flexible line was extended 2 km to take advantage of the Joule-Thomson cooling effect resulting from the pressure drop across the pipeline. In addition to defining the LLI properties, the flow-assurance study also examined the transient operation for both upstream and FLNG upon the closure of the riser shutdown valve. The study assessed flow-assurance issues, such as hydrates and adequacy of the slug receiver during the transient operation, that might arise, and defined the start-up and commissioning sequence for the facilities.

Advanced Controls for Fuel Consumption and Time-on-Wing Optimization in Commercial Aircraft Engines

2007 ◽  
Author(s):  
Daniel Viassolo ◽  
Aditya Kumar ◽  
Brent Brunell
Keyword(s):  
Steady State ◽  
Fuel Consumption ◽  
Flight Control ◽  
Operation Mode ◽  
Engine Performance ◽  
Current Control ◽  
Model Parameters ◽  
Transient Operation ◽  
Engine Model ◽  
Flight Envelope

This paper introduces an architecture that improves the existing interface between flight control and engine control. The architecture is based on an on-board dynamic engine model, and advanced control and estimation techniques. It utilizes a Tracking Filter (TF) to estimate model parameters and thus allow a nominal model to match any given engine. The TF is combined with an Extended Kalman Filter (EKF) to estimate unmeasured engine states and performance outputs, such as engine thrust and turbine temperatures. These estimated outputs are then used by a Model Predictive Control (MPC), which optimizes engine performance subject to operability constraints. MPC objective and constraints are based on the aircraft operation mode. For steady-state operation, the MPC objective is to minimize fuel consumption. For transient operation, such as idle-to-takeoff, the MPC goal is to track a thrust demand profile, while minimizing turbine temperatures for extended engine time-on-wing. Simulations at different steady-state conditions over the flight envelope show important fuel savings with respect to current control technology. Simulations for a set of usual transient show that the TF/EKF/MPC combination can track a desired transient thrust profile and achieve significant reductions in peak and steady-state turbine gas and metal. These temperature reductions contribute heavily to extend the engine time-on-wing. Results for both steady state and transient operation modes are shown to be robust with respect to engine-engine variability, engine deterioration, and flight envelope operating point conditions. The approach proposed provides a natural framework for optimal accommodation of engine faults through integration with fault detection algorithms followed by update of the engine model and optimization constraints consistent with the fault. This is a potential future work direction.

Performance Enhancement by Dynamic Valve Timing of a Multistage Vacuum Micropump

2010 ◽  
Author(s):  
Karthik Kumar ◽  
Luis P. Bernal ◽  
Khalil Najafi
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Pressure Difference ◽  
Performance Enhancement ◽  
High Vacuum ◽  
Operating Pressure ◽  
Transient Operation ◽  
Valve Timing ◽  
Steady State Operation ◽  
Valve Leakage

This paper presents the results of a theoretical analysis of dynamic valve timing on the performance of a multistage peristaltic vacuum micropump. Prior work has shown that for optimum steady state performance a fixed valve timing which depends on the operating pressure can be found. However, the use of a fixed valve timing could hinder performance for transient operation when the pump is evacuating a fixed volume. At the beginning of the transient the pump operates at low pressure difference and a large flow rate would be desirable. As the pump reaches high vacuum the pressure difference is large and the flow rate is necessarily small. Astle and coworkers1–3 have shown using a reduced order model that for steady state operation short valve open time results in lower inlet pressure and flow-rate and conversely. Here we extend the model of Astle and coworkers to include transient operation, multiple coupled stages and non-ideal leaky valves, and show that dynamic valve timing (DVT) reduces the transient duration by 30% compared to high vacuum pressure valve timing. The results also show a significant reduction in resonant frequency of the pump at low pressures, and quantify the effect of valve leakage.

A Predictive Ignition Delay Correlation Under Steady-State and Transient Operation of a Direct Injection Diesel Engine

2003 ◽  
Vol 125 (2) ◽  
pp. 450-457 ◽  
Author(s):  
D. N. Assanis ◽  
Z. S. Filipi ◽  
S. B. Fiveland ◽  
M. Syrimis
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Ignition Delay ◽  
Direct Injection ◽  
Thermodynamic Simulation ◽  
Injection Pressure ◽  
Transient Operation ◽  
Load Spectrum ◽  
Two Phase ◽  
Transient Conditions

Available correlations for the ignition delay in pulsating, turbulent, two-phase, reacting mixtures found in a diesel engine often have limited predictive ability, especially under transient conditions. This study focuses on the development of an ignition delay correlation, based on engine data, which is suitable for predictions under both steady-state and transient conditions. Ignition delay measurements were taken on a heavy-duty diesel engine across the engine speed/load spectrum, under steady-state and transient operation. The dynamic start of injection was calculated by using a skip-fire technique to determine the dynamic needle lift pressure from a measured injection pressure profile. The dynamic start of combustion was determined from the second derivative of measured cylinder pressure. The inferred ignition delay measurements were correlated using a modified Arrhenius expression to account for variations in fuel/air composition during transients. The correlation has been compared against a number of available correlations under steady-state conditions. In addition, comparisons between measurements and predictions under transient conditions are made using the extended thermodynamic simulation framework of Assanis and Heywood. It is concluded that the proposed correlation provides better predictive capability under both steady-state and transient operation.

Supercharging of SI Engines Using a New Kind of Screw-Type Supercharger

2001 ◽  
Author(s):  
K. von Rueden ◽  
H. Pucher ◽  
J. Nickel
Keyword(s):  
Slide Valve ◽  
Operating Conditions ◽  
Load Control ◽  
Transient Operation ◽  
Si Engine ◽  
Si Engines ◽  
New Type ◽  
Simulation Results ◽  
Stroke Cycle ◽  
Engine Power

Abstract In result of the permanent endeavor to reduce fuel consumption of vehicle engines, nowadays the implementation of downsizing concepts is being enforced. Thereby the desired nominal engine power can be produced by an engine with lower displacement operating with correspondingly higher charging pressure. Mechanical supercharging as well as turbocharging can be considered as a suitable supercharging method. This paper reports on experimental and simulation results regarding the stationary and transient operation of a four-stroke cycle SI passenger car engine supercharged by a new type of screw-type supercharger. In this manner the load control of the SI engine is performed by a supercharger internal slide valve system. Thus not only the throttling losses will be reduced noticeably, but also expansion work can be regained by this supercharger under certain operating conditions. The results obtained will be compared with those of the turbocharged reference engine.

An Electronically Controlled Automotive Gas Turbine

1979 ◽  
Author(s):  
P. Walzer ◽  
J. Meier-Grotrian ◽  
J. Mardell
Keyword(s):  
Control System ◽  
Steady State ◽  
Gas Turbine ◽  
Electronic Control ◽  
Transient Operation ◽  
Electronic Control System ◽  
Electronic Logic

The paper describes the use of an electronic control system with an experimental automotive gas turbine. A description of the gas turbine together with a summary of the control requirements is given. The resultant control system consisting of electronic logic and hydraulic interface components is presented. Finally, engine and vehicle behavior in steady-state and transient operation and reported.

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