The Effect of Bypass Valve Control on the Steady-State and Transient Performance of Diesel Engines with Regulated Two-Stage Turbocharging System

2015 ◽  
Author(s):  
Lei Shi ◽  
Hualei Li ◽  
Huiyan Zhang ◽  
Xiaojian Mao ◽  
Kangyao Deng ◽  
...  
Keyword(s):  
Steady State ◽  
Diesel Engines ◽  
Transient Performance ◽  
Two Stage ◽  
Bypass Valve ◽  
Turbocharging System ◽  
Valve Control

scholarly journals Research on the Power Recovery of Diesel Engines with Regulated Two-Stage Turbocharging System at Different Altitudes

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Hualei Li ◽  
Lei Shi ◽  
Kangyao Deng
Keyword(s):  
Diesel Engines ◽  
Control Strategies ◽  
Pressure Recovery ◽  
Boost Pressure ◽  
Two Stage ◽  
Bypass Valve ◽  
Turbocharging System ◽  
Power Recovery ◽  
Valve Control ◽  
Different Altitudes

Recovering the boost pressure is very important in improving the dynamic performance of diesel engines at high altitudes. A regulated two-stage turbocharging system is an adequate solution for power recovery of diesel engines. In the present study, the change of boost pressure and engine power at different altitudes was investigated, and a regulated two-stage turbocharging system was constructed with an original turbocharger and a matched low pressure turbocharger. The valve control strategies for boost pressure recovery, which formed the basis of the power recovery method, are presented here. The simulation results showed that this system was effective in recovering the boost pressure at different speeds and various altitudes. The turbine bypass valve and compressor bypass valve had different modes to adapt to changes in operating conditions. The boost pressure recovery could not ensure power recovery over the entire operating range of the diesel engine, because of variation in overall turbocharger efficiency. The fuel-injection compensation method along with the valve control strategies for boost pressure recovery was able to reach the power recovery target.

Aerodynamic interaction of turbines in a regulated two-stage turbocharging system

2021 ◽  
pp. 095440702110647
Author(s):  
Mingyang Yang ◽  
Lei Pan ◽  
Mengying Shu ◽  
Kangyao Deng ◽  
Zhanming Ding ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Internal Combustion Engines ◽  
Swirling Flow ◽  
Flow Analysis ◽  
Low Pressure ◽  
Two Stage ◽  
Operational Conditions ◽  
Low Pressure Turbine ◽  
Bypass Valve ◽  
Turbocharging System

Two-stage turbocharging becomes prevailing in internal combustion engines due to its advantage of flexibility of boosting for the variation of operational conditions. Two turbochargers are closely coupled by engine manifolds in the system especially under the requirement of compactness. This paper studies the influence of the interaction of two turbines in a two-stage turbocharging system on the performance. Results show that the performance of low-pressure turbine is highly sensitive to the stage interaction. Specifically, compared with the cases without interaction, the efficiency of low-pressure turbine increases maximumly by 2.8% when the bypass valve is closed, but reduces drastically by 7.5% when the valve is open. Detailed flow analysis shows that the combined results of swirling flow from the high-pressure turbine and the Dean vortex caused by the manifold elbow result in the alleviation of entropy generation in the turbine rotor. However, when the bypass valve is open, interaction of the swirling flow with the injected bypass flow results in strong secondary flow in the volute and distorted inlet flow condition for the rotor, leading to the enhancement of entropy generation in low-pressure turbine. The study provides valuable insights into turbine performance in a two-stage turbocharging system, which can be used for the modeling and optimization of multi-stage turbocharging systems.

Steady-state and transient control strategies for a two-stage turbocharged diesel engine

2017 ◽  
Vol 232 (9) ◽  
pp. 1167-1179 ◽  
Author(s):  
Zhilong Hu ◽  
Kangyao Deng ◽  
Yi Cui ◽  
Xinxin Yang ◽  
Baochuan Zhang
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Two Stage ◽  
Loop Control ◽  
Turbocharging System ◽  
Transient Control ◽  
Response Performance

Two-stage turbocharging technology is widely used to achieve higher engine power density and lower exhaust emissions. To solve a series of contradictions in matching, a regulated two-stage (RTS) turbocharging system is applied to reasonably control boost pressure. This paper investigated steady-state and transient control strategies for an RTS turbocharging system to achieve optimum fuel economy in steady-state conditions and better performance in transient conditions. The economic control strategies for steady-state operational conditions were based on an economic regulation law, which was established by a steady-state test of an engine with an RTS turbocharging system under all operating conditions. To optimize the transient performance, open-loop and closed-loop control systems (the latter with dynamic judgement) for the RTS system were designed and validated with experiments on a heavy-duty diesel engine. The experimental results demonstrated that the open-loop control strategy and the closed-loop strategy with dynamic judgement could improve the transient response performance. The optimum transient response performance was achieved by the closed-loop control system with dynamic judgement. Additionally, the combination of steady-state and transient control strategies could achieve the best fuel economy in steady-state conditions and good transient response performances.

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.

Simulation Study of the Impact of Two-Stage Turbocharged System on Diesel Engine

2012 ◽  
Vol 170-173 ◽  
pp. 3555-3559 ◽  
Author(s):  
Da Lu Dong ◽  
Chang Pu Zhao ◽  
Xiao Zhan Li ◽  
Yun Yao Zhu ◽  
Jun Zhang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Two Stage ◽  
Emission Regulations ◽  
Development Direction ◽  
Turbocharging System ◽  
Important Means ◽  
Software Code ◽  
The Impact ◽  
Original Experimental Data

With the increasing strictness of emission regulations, development direction of future diesel engines is toward the high thermal efficiency and low emissions. Supercharging technology is an important means for improving output power of diesel engines. This paper deals with the study of the two-stage turbocharging system of the non-road diesel engine. Based on GT-Power software code, a digital model of 6112 diesel engine was established. The supercharged model was calibrated by using the original experimental data. Then, four types of digital models with different two-stage turbocharging systems were constructed. The best two-stage turbocharging system was determined through investigating the impacts of different options on the performance of diesel engines. It was indicated through the study that two-stage turbocharging system can substantially increase the air flowing into the cylinder which increases the potential of power density. At the same time HC and NOx emissions can reduce. Through this study, a theoretical basis and an important reference for adopting the two-stage turbocharging system of the 6112 diesel engine were provided.

On the steady-state modelling of a two-stage evaporator system

2001 ◽  
Vol 25 (10) ◽  
pp. 859-880 ◽  
Author(s):  
M. N. A. Hawlader ◽  
S. K. Chou ◽  
K. J. Chua ◽  
J. C. Ho ◽  
A. S. Mujumdar
Keyword(s):  
Steady State ◽  
Two Stage
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