scholarly journals A Mean Value Model for Unsteady Gas Flows and Heat Transfer in Pipes

Author(s):  
Olov Holmer ◽  
Lars Eriksson
Author(s):  
Byungchan Lee ◽  
Dohoy Jung ◽  
Yong-Wha Kim

A Physics-based mean value model that predicts engine combustion, heat transfer, gas exchange, and friction loss has been developed. The model is developed starting from the thermodynamic principles of an ideal gas standard limited pressure cycle concept. The idealized assumptions that are typically used in a limited pressure cycle concept are relieved to enhance the fidelity of the model by introducing variables that account for the in-cylinder heat transfer and the combustion characteristics that change under varying EGR rate as well as the engine speed and load while minimal number of empirical correlations are used to ensure the compactness and flexibility of the physics-based mean value model. The model is calibrated and validated with the simulation results from a detailed GT-Power® engine model previously calibrated with experimental results from a Ford 6.7 liter Diesel engine. The comparison shows good agreement between the results from the mean value model and the GT-Power® model. The mean value model developed in this study is a flexible simulation tool that provides excellent computational efficiency without sacrificing critical physical details of the Diesel combustion process required by the control design development.


2005 ◽  
Author(s):  
M. Canova ◽  
L. Garzarella ◽  
M. Ghisolfi ◽  
S. Midlam-Mohler ◽  
Y. Guezennec ◽  
...  

2012 ◽  
Author(s):  
Augusto F. Pacheco ◽  
Jonas R. Tibola ◽  
Mario E. S. Martins ◽  
Paulo R. M. Machado ◽  
Humberto Pinheiro ◽  
...  

2004 ◽  
Vol 127 (3) ◽  
pp. 355-362 ◽  
Author(s):  
D. J. Rausen ◽  
A. G. Stefanopoulou ◽  
J.-M. Kang ◽  
J. A. Eng ◽  
T.-W. Kuo

A Mean Value Model (MVM) for a Homogeneous Charge Compression Ignition (HCCI) engine is presented. Using a phenomenological zero-dimensional approach with five continuous and three discrete states we first model the effects of the Exhaust Gas Recirculation (EGR) valve, the exhaust Rebreathing Lift (RBL), and the fueling rate on the state of charge in the cylinder at intake valve closing. An Arrhenius integral is then used to model the start of combustion, θsoc. A series of simple algebraic relations that captures the combustion duration and heat release is finally used to model the state of charge after the HCCI combustion and the Location of Peak Pressure (LPP). The model is parametrized and validated using steady-state test data from an experimental gasoline engine at the General Motors Corporation. The simple model captures the temperature, pressure, air-to-fuel ratio, and inert gas fraction of the exhausted mass flow. This characterization is important for the overall HCCI dynamics because the thermodynamic state (pressure, temperature) and concentration (oxygen and inert gas) of the exhausted mass flow affect the next combustion event. The high dilution level in HCCI engines increases the significance of this internal feedback that generally exists to a smaller extent in conventional spark-ignition and compression-ignition internal combustion engines.


Author(s):  
Mike J. Hand ◽  
Erik Hellström ◽  
Doohyun Kim ◽  
Anna Stefanopoulou ◽  
Justin Kollien ◽  
...  

A control-oriented model and its associated tuning methodology is presented for the air path of a six cylinder 13 L diesel engine equipped with an asymmetric twin-scroll turbine, wastegate (WG), and exhaust gas recirculation (EGR). This model is validated against experimental engine data and shows good agreement. The small scroll of the asymmetric twin scroll turbine is fed by the exhaust of three cylinders via a split manifold that operates at higher pressure than the exhaust manifold feeding the larger turbine scroll. The asymmetric design with the high exhaust back pressure on three of the six cylinders gives the necessary EGR capability, with reduced pumping work, but leads to complex flow characteristics. The mean-value model describes the flows through the engine, the flow through the two turbine scrolls, the EGR flow, and the WG flow as they are defined, and defines the pressure of the manifolds they connect to. Using seven states that capture the dynamics of the pressure and composition in the manifolds and the speed of the turbo shaft, the model can be used for transient control, along with set point optimization for the EGR and WG flows for each speed and load condition. The relatively low order of the model makes it amenable to fast simulations, system analysis, and control design.


2013 ◽  
Vol 5 ◽  
pp. 579503 ◽  
Author(s):  
Ruixue Li ◽  
Ying Huang ◽  
Gang Li ◽  
Kai Han ◽  
He Song

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