Miller Cycle-Regulatable Two Stage Turbocharging System Design of Marine Diesel Engines

2012 ◽  
Author(s):  
Yi Cui ◽  
Zhilong Hu ◽  
Kangyao Deng ◽  
Qifu Wang
Keyword(s):  
Simulation Model ◽  
System Design ◽  
High Speed ◽  
Combustion Model ◽  
Nox Emissions ◽  
Miller Cycle ◽  
Two Stage ◽  
Cycle Simulation ◽  
Turbocharging System ◽  
Marine Diesel

Satisfying the coming International Marine Organization (IMO) NOx emissions requirements and regulations is the main focus of attention in marine engine design. Miller cycle, which reduces in-cylinder combustion temperature by reducing effective compression ratio, is the main measure to reduce NOx specific emissions on the cost of volumetric efficiency and engine power. Therefore, it is essential to combine Miller cycle with highly boosted turbocharging system, for example, two stage turbocharing, to recover the power. In this paper, different two stage turbocharging system scenarios are introduced and compared. The system design and matching process is presented. A multi-zone combustion model based one dimensional cycle simulation model is established. The intake valve closure timing and the intake exhaust valves overlap duration are optimized according to the IMO NOx emission limits by the simulation model. The high and low stage turbochargers are selected by an iterative matching method. Then the control strategies of the boost air and the high stage turbine bypass valves are also studied. As an example, a Miller cycle-regulatable two stage turbocharging system is designed for a type of highly boosted high speed marine diesel engine. The results show that the NOx emissions can be reduced 30% and break specific fuel consumption can also be improved by means of moderate Miller cycle combined with regulatable two stage turbocharing.

Miller-Cycle Regulatable, Two-Stage Turbocharging System Design for Marine Diesel Engines

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Yi Cui ◽  
Zhilong Hu ◽  
Kangyao Deng ◽  
Qifu Wang
Keyword(s):  
Diesel Engines ◽  
Optimization Design ◽  
System Optimization ◽  
Nox Emission ◽  
Combustion Model ◽  
Miller Cycle ◽  
Two Stage ◽  
Cycle Simulation ◽  
Turbocharging System ◽  
Marine Diesel

The increasingly stringent NOx emission regulations of the International Marine Organization (IMO) have demanded new design concepts and architectures for diesel engines. The Miller cycle, which reduces the in-cylinder combustion temperature by reducing the effective compression ratio, is the principal measure used for reducing NOx specific emissions; however, this is at the cost of volumetric efficiency and engine power. Therefore, it is essential to combine the Miller cycle with a highly boosted turbocharging system, two-stage turbocharging for example, to recover the power. While much work has been done in the development of Miller-cycle regulatable two stage turbocharging system for marine diesel engines, there are nonetheless few, if any, thorough discussions on system optimization and performance comparison. This study presents a theoretical optimization design process for a Miller-cycle regulatable, two-stage turbocharging system for marine diesel engines. First, the different scenarios and regulation methods of two-stage turbocharging systems are compared according to the system efficiency and equivalent turbine flow characteristics. Then, a multizone combustion model based on a one-dimensional cycle simulation model is established and used for the optimization of valve timings according to the IMO NOx emission limits and fuel efficiencies. The high- and low-stage turbochargers are selected by an iterative matching method. Then, the control strategies for the boost air and high-stage turbine bypass valves are also studied. As an example, a Miller-cycle regulatable, two-stage turbocharging system is designed for a highly boosted high-speed marine diesel engine. The results show that NOx emissions can be reduced by 30% and brake specific fuel consumption (BSFC) can also be improved by a moderate Miller cycle combined with regulatable two-stage turbocharging.

Performance Calculation of a TBD234V12 Diesel Engine with STC

2012 ◽  
Vol 157-158 ◽  
pp. 1075-1078
Author(s):  
Yang Wang ◽  
Yin Yan Wang ◽  
Fan Shi ◽  
Xin Guang Li
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Computer Model ◽  
High Speed ◽  
Marine Diesel Engine ◽  
High Speed Diesel ◽  
Turbocharging System ◽  
Marine Diesel ◽  
Performance Calculation ◽  
Good Agreement

A computer model for a TBD234V12 marine high-speed diesel engine with 2 turbocharger(2TC) is built on GT-POWER. For validating the computer model, a calculation to the conventional turbocharging system has been done firstly, and the results show good agreement with experimental data. The computer model has then been used for predictive studies of the diesel engine with the proposed STC system on the mapping characteristics. From these results, it can be seen that the STC system can not only improve the part load performance of the diesel engine obviously, but also enlarge the operating range of the marine diesel engine.

A Study on an Automatically Variable Intake Exhaust Injection Timing Turbocharging System for Diesel Engines

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Shiyou Yang ◽  
Kangyao Deng ◽  
Yi Cui ◽  
Hongzhong Gu
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
High Speed ◽  
Control Mechanism ◽  
Operating Conditions ◽  
Combustion Model ◽  
Injection Timing ◽  
Low Speed ◽  
Turbocharging System ◽  
High Torque

A new turbocharging system, named automatically variable intake exhaust injection timing (AVIEIT), is proposed. Its main purpose is to improve the performance of low-speed high torque operating conditions and improve the economy of high-speed operating conditions for high-speed supercharged intercooled diesel engines. The principle of the AVIEIT turbocharging system is presented. A control mechanism for the proposed AVIEIT system used for a truck diesel engine is introduced. An engine simulation code has been developed. In this code, a zero-dimensional in-cylinder combustion model, a one-dimensional finite volume method-total variation diminishing model for unsteady gas flow in the intake and exhaust manifolds, and a turbocharger model are used. The developed code is used to simulate the performances of diesel engines using the AVIEIT system. Simulations of a military use diesel engine “12V150” and a truck diesel engine “D6114” using the AVIEIT system have been performed. Simulation results show that the in-cylinder charge air amount of the diesel engine with the AVIEIT system is increased at low-speed high torque operating conditions, and the fuel economy is improved at high-speed operating conditions. In order to test the idea of the AVIEIT system, an experiment on a truck diesel engine D6114 equipped with an AVIEIT control mechanism has been finished. The experiment results show that the AVIEIT system can improve the economy of high-speed operating conditions. Both the simulation and experiment results suggest that the AVIEIT system has the potential to replace the waste-gate and variable geometry turbocharger turbocharging systems.

Virtual High Speed Diesel Engine – A Simulated Experiment, Part I: Combustion Dynamics

2014 ◽  
Vol 659 ◽  
pp. 189-194
Author(s):  
Lidia Gaiginschi ◽  
Iulian Agape ◽  
Adrian Sachelarie ◽  
Mihai Alin Girbaci
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Operating Regime ◽  
Combustion Model ◽  
Combustion Dynamics ◽  
Cycle Simulation ◽  
Simulated Experiment ◽  
High Speed Diesel

The research efforts in the direction of internal combustion engines functional cycle simulation, particularly for small capacity diesel engines, are justified by shortening the path between the new conceptual solution and its effects and also to reduce research costs. There can be adopted new organizational and management solutions for the combustion process after these, for example, confirm at the model level. This paper proposes an unizonal physico-mathematical combustion model in high speed small Diesel engines, based on a Vibe-type law and on the heat transfer through the combustion chamber walls modelated after Woschni. The complexity of the model justifies the name of „virtual engine”. This allows to determine the functional parameters as instantaneous and average values, at any engine operating regime. The simulated experiment takes place in perfectly controlled conditions and leads to good results. There are obtained, during the combustion process, dynamics of parameters concerning the vaporization characteristics, combustion characteristics and combustion kinetics, for any operating regime. The parameters are evolving in a predictable way, being experimentally confirmed.

Turbocharging System Design and Performance Analysis of a Marine Diesel Engine

2013 ◽  
Author(s):  
Yi Cui ◽  
Kangyao Deng ◽  
Lei Shi
Keyword(s):  
High Speed ◽  
Constant Pressure ◽  
Fuel Efficiency ◽  
Exhaust Gas ◽  
Low Speed ◽  
Turbocharging System ◽  
Marine Diesel ◽  
Pulse Converter ◽  
And Performance ◽  
Load Conditions

The selection of turbocharging systems for 8-cylinder marine diesel engines is difficult due to the existence of scavenge interference between cylinders. The constant pressure and pulse converter turbocharging systems have been used to eliminate the scavenge interference by applying large volume exhaust manifolds or grouped exhaust branches according to the firing order. But, the performance of constant pressure turbocharging system under low speed conditions of propulsion characteristics and transient conditions is poor, because of less available exhaust gas energy. The structure and arrangement of pulse converter turbocharging system is complex, meanwhile, and the performance at high speed and loads is not as good. In this paper, three new turbocharging systems, such as, MIXPC (mixed pulse converter) system, dual-turbocharger system (DTS) and controllable exhaust system (CES) were designed to improve the performance of a marine diesel engine. In the upstream part of MIXPC system, the separated small diameter branch pipes were used to isolate the exhaust gas interference. In the downstream part of MIXPC system, the single main pipe was connected with one entry turbocharger to improve the operation efficiency of the turbocharger. In the DTS, two one-entry turbochargers were used, one of which connected with 4 cylinders by two branch pipes and a mixer. The two cylinders with firing intervals of 270 crank angles were connected with one branch pipe. In the CES, a control valve was used to control the exhaust gas flow. The valve was opened at high speed and load conditions and closed at low speed and load conditions. The steady and transient performance of the three turbocharging systems was analyzed by simulation. The experimental studies were also carried out to compare the performance of the three turbocharging systems. The experimental results showed that the CES had the best fuel efficiency under low speed and load conditions, and the DTS had the best fuel efficiency under high speed and load conditions. Compared with the MIXPC system, the overall brake specific fuel consumption under propeller operating conditions was reduced by 11.3g/kWh with DTS and 5.3g/kWh with CES. But the uniformity of exhaust gas temperatures of cylinder heads was the best for MIXPC system. In general, the DTS was superior considering the structure simplicity and performance of the engine.

scholarly journals Investigation of the Miller cycle on the performance and emission in a natural gas-diesel dual-fuel marine engine by using two zone combustion model

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 259-270 ◽  
Author(s):  
Huibing Gan ◽  
Huaiyu Wang ◽  
YuanYuan Tang ◽  
GuanJie Wang
Keyword(s):  
Compression Ratio ◽  
Combustion Model ◽  
Dual Fuel ◽  
Nox Emissions ◽  
Miller Cycle ◽  
Intake Valve ◽  
Performance And Emission ◽  
Working Volume ◽  
Crank Angle ◽  
Temperature Heat

Compared to the standard cycle, the Miller cycle decreases the cylinder maximum combustion temperature which can effectively reduce NOX emissions. In this paper, a zero-dimensional two-zone combustion model is used to establish the simulation model of a marine dual-fuel engine, which is calibrated according to the test report under different loads. Due to the high emissions under part load, the Miller cycle (early intake valve closing method) is used for optimization. By analyzing the cylinder pressure, temperature, heat release rate and NOx emissions under different cases, it can be found that the effective working volume and thermal efficiency decrease with the advance of intake valve closing and improve with the increase of the geometric compression ratio. In all optimization cases, the NOX emissions and fuel consumption are reduced by 72% and 0.1%, respectively, by increasing the geometric compression ratio to 14 and the intake valve closing timing to 510 degree of crank angle (The reference top dead center is 360 degree of crank angle). The simulation results show that the early intake valve closing Miller cycle can effectively reduce the NOX emissions and cylinder peak pressure.

Study on the Regulation Boundary for Two-Stage Turbocharging System at Different Altitudes

2017 ◽  
Author(s):  
Huiyan Zhang ◽  
Hualei Li ◽  
Mengyu Li ◽  
Lei Shi ◽  
Kangyao Deng
Keyword(s):  
High Speed ◽  
Two Stage ◽  
Brake Torque ◽  
Control Valves ◽  
Speed Condition ◽  
Closed Area ◽  
High Stage ◽  
Turbocharging System ◽  
Boundary Model ◽  
Different Altitudes

Regulated two-stage (RTS) turbocharging system is an effective way to enhance power density and reduce pollutant of internal combustion engine for increasingly stringent demands of fuel consumption and emission regulation. Due to achieving high boost pressure with great system efficiency and controllable characteristic in wide working range, the RTS turbocharging system improves output power at low speed condition and reduces pumping loss at high speed condition. Composing of two turbochargers and control valves, the RTS turbocharging system is matched with engine at a design point and regulated by adjusting control valves to meet the engine requirement of intake pressure and flow at other working conditions. Calibration of the control valves under all operating conditions by plentiful experiments is significant for turbocharging system, particularly that matched with diesel engine for vehicle. Moreover, when an automobile run on the plateau, the intake air flow will decrease and combustion in cylinder will deteriorate obviously. Compared with other turbocharging system, two-stage turbocharging system is more suitable to the offset power loss of engine. Regulating boost system under different operation conditions draws more attention to engine performance recovery so that the workload of calibration raises rapidly in consideration of altitude factor. Though much work has been done in calibration at various altitudes, there are few, if any, discussion on open-closed boundary of control valves to simplify the calibration process. In this paper, it aims to present a regulation boundary model of control valve at different altitudes to guide the calibration and a series of experiments for RTS system can be saved. Firstly, a thermodynamics analysis of the RTS turbocharging system is conducted and typical regulation methods are compared in terms of the adjustment capacity and efficiency characteristics of turbocharging system, which indicates that high-stage turbine bypass is the optimum regulation method. Then, a regulation boundary model for the RTS turbocharging system at different altitudes is deduced, according to the relation of equivalent turbine area and engine operating condition. The regulation boundaries of different altitudes are obtained by iterative computation of the model, and the whole working mode of the RTS system is divided into a fully closed area and a regulated area. Experiments are carried out to verify the regulation boundary model at sea level condition. Brake torque, efficiency of the RTS system and temperature before high-stage turbine are primary parameters for verification in this article. The maximum error shows up with a value of 3.65% brake torque at 2200rpm. While a one-dimensional simulation model is built up to validate the regulation boundary model of the plateau. All the errors are smaller than 3% at various altitudes. It results that model is accurate enough to predict the regulation boundary of the RTS system. By the calculation of regulation boundary model, the brake torque at regulation boundary will decrease if the engine speeds up. It also manifests that fully closed area will argument if the automobile climbs up to high operating altitude, especially under high speed condition.

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