Development and Application of a Complete Multijet Common-Rail Injection-System Mathematical Model for Hydrodynamic Analysis and Diagnostics

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Andrea E. Catania ◽  
Alessandro Ferrari ◽  
Michele Manno
Keyword(s):  
Mathematical Model ◽  
Wave Propagation ◽  
Flow Rate ◽  
Performance Optimization ◽  
Common Rail ◽  
Injection System ◽  
Numerical Code ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
Time Histories

A rather complete mathematical model for a common-rail injection-system dynamics numerical simulation was developed to support experimentation, layout, and control design, as well as performance optimization. The thermofluid dynamics of the hydraulic-system components, including rail, connecting pipes, and injectors was modeled in conjunction with the solenoid-circuit electromagnetics and the mechanics of mobile elements. One-dimensional flow equations in conservation form were used to simulate wave propagation phenomena throughout the high-pressure connecting pipes, including the feeding pipe of the injector nozzle. In order to simulate the temperature variations due to the fuel compressibility, the energy equation was used in addition to mass conservation and momentum balance equations. Besides, the possible cavitation phenomenon effects on the mass flow rate through the injector bleed orifice and the nozzle holes were taken into account. A simple model of the electromagnetic driving circuit was used to predict the temporal distribution of the force acting on the pilot-valve anchor. It was based on the experimental time histories of the current through the solenoid and of the associated voltage that is provided by the electronic control unit to the solenoid. The numerical code was validated through the comparison of the prediction results with experimental data, that is, pressure, injected flow rate, and needle lift time histories, taken on a high performance test bench Moehwald-Bosch MEP2000-CA4000. The novel injection-system mathematical model was applied to the analysis of transient flows through the hydraulic circuit of a commercial multijet second-generation common-rail system, paying specific attention to the wave propagation phenomena, to their dependence on solenoid energizing time and rail pressure, as well as to their effects on system performance. In particular, an insight was also given into the model capability of accurately predicting the wave dynamics effects on the rate and mass of fuel injected when the dwell time between two consecutive injections is varied.

Development and Application of a Complete Common-Rail Injection System Mathematical Model for Hydrodynamic Analysis and Diagnostics

2005 ◽  
Author(s):  
Andrea Emilio Catania ◽  
Alessandro Ferrari ◽  
Michele Manno
Keyword(s):  
Mathematical Model ◽  
Wave Propagation ◽  
Flow Rate ◽  
Performance Optimization ◽  
Common Rail ◽  
Injection System ◽  
Numerical Code ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
Time Histories

A rather complete mathematical model for a Common Rail injection-system dynamics numerical simulation was developed to support experimentation, layout and control design, as well as performance optimization. The thermo-fluid dynamics of the hydraulic system components, including rail, connecting pipes and injectors was modeled in conjunction with the solenoid-circuit electromagnetics and the mechanics of mobile elements. Onedimensional flow equations in conservation form were used to simulate wave propagation phenomena throughout the high-pressure connecting pipes, including the feeding pipe of the injector nozzle. In order to simulate the temperature variations due to the fuel compressibility, the energy equation was used in addition to mass conservation and momentum balance equations. Besides, the possible cavitation phenomena effects on the mass flow rate through the injector bleed orifice and the nozzle holes were taken into account. A simple model of the electromagnetic driving circuit was used to predict the temporal distribution of the force acting on the pilot-valve anchor. It was based on the experimental time-histories of the current through the solenoid and of the associated voltage that is provided by the electronic control unit (ECU) to the solenoid valve. The numerical code was validated through the comparison of the prediction results with experimental data, that is, pressure, injected flow rate and needle lift time-histories, taken on a high performance test bench Moehwald-Bosch MEP2000-CA4000. The novel injection-system mathematical model was applied to the analysis of transient flows through the hydraulic circuit of a commercial multijet second-generation Common Rail system, paying specific attention to the wave propagation phenomena, to their dependence on solenoid energizing time and rail pressure, as well as to their effects on system performance. An insight was also given into the model capability of accurately predicting the wave dynamics effects on the rate and mass of fuel injected when the dwell time between two consecutive injections is varied.

Integrated Modelling of Fuel Influence on Common Rail Injection System Performance

2006 ◽  
Author(s):  
O. Chiavola ◽  
F. Palmieri ◽  
G. Chiatti
Keyword(s):  
Flow Rate ◽  
Injection Pressure ◽  
Common Rail ◽  
Injection System ◽  
Integrated Modelling ◽  
Nozzle Flow ◽  
Common Rail System ◽  
Local Flow ◽  
Common Rail Injection System ◽  
Common Rail Injection

A model for the analysis of diesel engine common rail injection system has been developed and the influence that different fuels have on the injection performances has been investigated. Diesel fuel, biodiesel and kerosene have been used and the differences of injection flow rate, injection pressure time trace, nozzle flow features and break up mechanism have been highlighted. The coupling of two different codes has been used in the simulations: the former one, AMESim code, has been adopted to model the common rail system and to investigate the fuel flow rate and the injection pressure dependence on the fuel type. The latter computational tool, FIRE code, has been initialized by means of the results obtained from the injection system simulation and has been used to perform the 3D investigation of the internal nozzle flow and of the spray formation phenomena, aimed at evaluating the effect of physical fuel features on local flow characteristics and their influence on the system performances. Details of the adopted modeling strategy are described and results of each simulation step are presented.

Numerical Simulations by Detailed Chemistry and Experimental Measurements of Diesel Combustion in a Light Duty Common Rail Direct Injection Engine

2005 ◽  
Author(s):  
Michela Costa ◽  
Bianca M. Vaglieco ◽  
Felice E. Corcione ◽  
Hiroshi Omote
Keyword(s):  
Diesel Fuel ◽  
Digital Images ◽  
Direct Injection ◽  
Computational Cost ◽  
Diesel Oil ◽  
Common Rail ◽  
Injection System ◽  
Numerical Code ◽  
Detailed Chemistry ◽  
Common Rail Injection System

Present paper couples the use of a modified version of the KIVA-3V code including a model for detailed chemistry to an experimental investigation performed on an optically accessible diesel engine. The engine is equipped with a commercial four valves cylinder head and a Common Rail injection system. Digital images and UV-visible flame emission measurements are compared with the visualization of the numerical results. The diesel fuel surrogate is considered within the numerical code, namely a blend consisting of n-heptane and toluene, approximating the physical and ignition properties of the diesel oil. Products, soot and NOx formation is described by a chain of 283 reactions involving 69 species. The Partially Stirred Reactor (PaSR) assumption is adopted to maintain the computational cost within acceptable limits. The collections of digital images of the spray evolution, the mixture formation and the combustion processes are undertaken by running the engine at 1000 rpm. Commercial diesel fuel is injected by using a single injection.

Ion Current, Combustion and Emission Characteristics in an Automotive Common Rail Diesel Engine

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Naeim A. Henein ◽  
Tamer Badawy ◽  
Nilesh Rai ◽  
Walter Bryzik
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Direct Injection ◽  
Common Rail ◽  
Ion Current ◽  
Injection System ◽  
Feedback Signal ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
No Emissions

Advanced electronically controlled diesel engines require a feedback signal to the ECU to adjust different operating parameters and meet demands for power, better fuel economy and low emissions. Different types of in-cylinder combustion sensors are being considered to produce this signal. This paper presents results of an experimental investigation on the characteristics of the ion current in an automotive diesel engine equipped with a common rail injection system. The engine is a 1.9 L, 4-cylinder, direct injection diesel engine. Experiments covered different engine loads and injection pressures. The relationships between the ion current, combustion parameters and engine out NO emissions and opacity are presented. The analysis of the experimental data identified possible sources of the ion current produced in diesel engines.

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