Modeling Cylinder-to-Cylinder Coupling in Multi-Cylinder HCCI Engines Incorporating Reinduction

2007 ◽  
Author(s):  
Anup M. Kulkarni ◽  
Gayatri H. Adi ◽  
Gregory M. Shaver
Keyword(s):  
Internal Combustion Engines ◽  
Control Strategies ◽  
Combustion Products ◽  
Exhaust Manifold ◽  
Gas Temperature ◽  
Subtle Difference ◽  
Hcci Engine ◽  
Variable Valve Actuation ◽  
Hcci Engines ◽  
Valve Actuation

Residual-affected homogeneous charge compression ignition (HCCI) is a promising strategy for decreasing fuel consumption and NOx emissions in internal combustion engines. One practical approach for achieving residual-affected HCCI is by using variable valve actuation to reinduct previously exhausted combustion products. This process inherently couples neighboring engine cylinders as products exhausted by one cylinder may be reinducted by a neighboring one. In order to understand this coupling and its implication for controlling HCCI, this paper outlines a simple physics based model of a multi-cylinder HCCI engine using exhaust reinduction. It is based on a physics based model previously validated for a single cylinder, multi mode HCCI engine. The exhaust manifold model links exhaust gases from one cylinder to those of the other cylinders and also simulates the effect of exhaust reinduction from the previous cycle. Depending on the exhaust manifold geometry and orientation, the heat transfer in the manifold causes a difference in the temperature of the re-inducted product gas across the cylinders. The results show that a subtle difference in the re-inducted exhaust gas temperature results in a dramatic variation in combustion timing (approx. 3 degrees). This model provides a basis for understanding the steady state behavior and also for developing control strategies for multi-cylinder HCCI engines. The paper presents exhaust valve timing induced compression ratio modulation (via flexible valve actuation) as one of the approaches to mitigate the imbalance in combustion timing across cylinders.

A physics-based approach to the control of homogeneous charge compression ignition engines with variable valve actuation

2005 ◽  
Vol 6 (4) ◽  
pp. 361-375 ◽  
Author(s):  
G M Shaver ◽  
M J Roelle ◽  
P A Caton ◽  
N B Kaahaaina ◽  
N Ravi ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Homogeneous Charge Compression Ignition ◽  
Control Strategies ◽  
Combustion Process ◽  
System Control ◽  
Compression Ignition ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Homogeneous Charge ◽  
Valve Actuation

Homogeneous charge compression ignition (HCCI) is a promising low-temperature combustion strategy for reducing NOx emissions and increasing efficiency in internal combustion engines. However, HCCI has no direct combustion initiator and, when achieved by reinducting or trapping residual exhaust gas with a variable valve actuation (VVA) system, becomes a dynamic process as the temperature of the residual gas couples one cycle to the next. These characteristics of residual-affected HCCI present a challenge for control engineers and a barrier to implementing HCCI in a production engine. In order to address these challenges, this paper outlines physics-based control strategies for both the VVA system and the HCCI combustion process. The results show that VVA system control can provide arbitrary valve timings on a cycle-to-cycle basis, enabling tight control of HCCI. By abstracting these valve timings further into an inducted gas composition and an effective compression ratio, model-based controllers can be developed to control simultaneously load and combustion timing in an HCCI engine.

Using Co-Simulation Methods to Establish Variable Valve Actuation Hardware Specifications and Control Strategies

2001 ◽  
Author(s):  
Reinhard Burk ◽  
Frederic Jacquelin ◽  
Russell Wakeman
Keyword(s):  
Internal Combustion Engines ◽  
Production Systems ◽  
Control Strategies ◽  
Engine Performance ◽  
Cost Effective ◽  
Dynamics Simulation ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
And Control ◽  
Valve Actuation

Abstract With the increasing recognition that variable valve actuation (VVA) in its various forms is a powerful tool for optimizing the performance of internal combustion engines, more and more production systems are being designed and implemented throughout the industry. However, as these control systems become more capable of altering lift, timing, duration, and even the number of valve events, the complexity of designing algorithms and calibrating them becomes enormous. In addition, without prior knowledge of an engine’s response to these algorithms, designing a cost-effective mechanism which provides adequate but not over-reaching capability is difficult. Ricardo has developed methodology for timestep coupled simulations which enables the use of one-dimensional (1-D) gas dynamics simulation of engine performance (WAVE™) coupled to a simulation of the valve actuation mechanism constructed in MATLAB® and AMESim®. This arrangement allows valve motion input to the 1-D code to be controlled either manually or by a VVA controller simulation, allowing such engine parameters as torque, fuel consumption, NVH, and EGR rates to be monitored as a function of valve timing strategy. This method allows the examination of such engine development concerns as tolerances, valve velocities and accelerations, and interactions with other engine controls to be studied without the costs, leadtimes, or hardware reliability problems that are associated with prototyping a VVA system. In addition, the interfacing of the valve control/engine performance simulation combination with the Design of Experiments optimization software iSIGHT allows the control system space to be explored automatically, without the brute force numerical search required to examine all permutations of the control strategies. The output of this procedure is an array of requirements which can be quickly translated into a specification document which will guide hardware and controls design efforts.

A Theoretical Study on Performance and Combustion Characteristics of HCCI Engine Operation With Diesel Surrogate Fuels: n-Heptane, Dimethyl Ether

2008 ◽  
Author(s):  
Seyed Navid Shahangian ◽  
Mojtaba Keshavarz ◽  
Ghasem Javadirad ◽  
Nader Bagheri ◽  
Seyed Ali Jazayeri
Keyword(s):  
Dimethyl Ether ◽  
Diesel Fuel ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Main Stage ◽  
Engine Operation ◽  
Hcci Engine ◽  
Second Stage ◽  
Hcci Engines

HCCI engines have low emission and high efficiency values compared to the conventional internal combustion engines. These engines can operate on most alternative fuels such as dimethyl ether (DME), which has been tested as a possible diesel fuel for its simultaneously reduced NOx and PM emissions. HCCI combustion of both DME and n-heptane fuels display a distinct two-stage ignition reaction with the first stage taking place at fairly low temperatures and the second stage taking place at high temperatures. The second stage is responsible for the main stage of the heat release process. In this study, a single-zone, zero-dimensional, thermo-kinetic combustion model has been developed. MATLAB software is used to predict engine performance characteristics of HCCI engines using two types of diesel fuel: Dimethyl ether and N-heptane. The effects of intake temperature and pressure, fuel loading and addition of EGR gases on auto-ignition characteristics, optimum combustion phasing, and performance of the HCCI engines are considered in this study. Simultaneous effects of these variables for finding the most appropriate regime of HCCI engine operation, considering knock and misfire boundaries, are also investigated.

scholarly journals Modeling Cycle-to-Cycle Coupling in HCCI Engines Utilizing Variable Valve Actuation

2004 ◽  
Vol 37 (22) ◽  
pp. 227-232 ◽  
Author(s):  
Gregory M. Shaver ◽  
Matthew Roelle ◽  
J. Christian Gerdes
Keyword(s):  
Variable Valve Actuation ◽  
Hcci Engines ◽  
Variable Valve ◽  
Valve Actuation

A Physics-Based Modeling Approach of a Natural Gas HCCI Engine

2012 ◽  
Author(s):  
Marwa W. AbdelGawad ◽  
Reza Tafreshi ◽  
Reza Langari
Keyword(s):  
Internal Combustion Engines ◽  
Integral Model ◽  
Compression Ignition ◽  
Valve Closure ◽  
Nitric Oxides ◽  
Intake Valve ◽  
Ignition Timing ◽  
Hcci Engine ◽  
Main Challenge ◽  
Hcci Engines

Homogeneous Charge Compression Ignition (HCCI) Engines hold promises of being the next generation of internal combustion engines due to their ability to produce high thermal efficiencies, in addition to low nitric oxides and particulate matter. HCCI combustion is achieved through the auto-ignition of a compressed homogenous fuel-air mixture, thus making it a “fusion” between spark-ignition and compression-ignition engines. The main challenge in developing HCCI engines is the absence of a combustion trigger hence making the control of combustion timing difficult. To be able to control ignition timing, a physics-based model is developed to model the full HCCI engine cycle while taking into consideration cycle-to-cycle transitions. Exhaust Gas Recirculation is used to control combustion timing while the temperature at intake valve closure will serve as the parameter that represents the desired ignition timing. The Modified Knock Integral model defines the necessary relationship between ignition timing and temperature at intake valve closure. Validation of the developed model is performed by determining the ignition timing under varying conditions. Results are shown to be in accordance with data acquired from a single-cylinder model developed using a sophisticated engine simulation program, GT-Power.

Grey-Box Modeling for HCCI Engine Control

2013 ◽  
Author(s):  
M. Bidarvatan ◽  
M. Shahbakhti
Keyword(s):  
Real Time ◽  
Operating Conditions ◽  
Box Model ◽  
Average Error ◽  
Engine Control ◽  
Gas Temperature ◽  
Real Time Control ◽  
Time Model ◽  
Hcci Engine ◽  
Hcci Engines

High fidelity models that balance accuracy and computation load are essential for real-time model-based control of Homogeneous Charge Compression Ignition (HCCI) engines. Grey-box modeling offers an effective technique to obtain desirable HCCI control models. In this paper, a physical HCCI engine model is combined with two feed-forward artificial neural networks models to form a serial architecture grey-box model. The resulting model can predict three major HCCI engine control outputs including combustion phasing, Indicated Mean Effective Pressure (IMEP), and exhaust gas temperature (Texh). The grey-box model is trained and validated with the steady-state and transient experimental data for a large range of HCCI operating conditions. The results indicate the grey-box model significantly improves the predictions from the physical model. For 234 HCCI conditions tested, the grey-box model predicts combustion phasing, IMEP, and Texh with an average error less than 1 crank angle degree, 0.2 bar, and 6 °C respectively. The grey-box model is computationally efficient and it can be used for real-time control application of HCCI engines.

Numerical Analysis of Biogas Composition Effects on Combustion Parameters and Emissions in Biogas Fueled HCCI Engines for Power Generation

2011 ◽  
Author(s):  
Iva´n D. Bedoya ◽  
Samveg Saxena ◽  
Francisco J. Cadavid ◽  
Robert W. Dibble
Keyword(s):  
Numerical Model ◽  
Power Output ◽  
Internal Combustion Engines ◽  
Numerical Results ◽  
Experimental Results ◽  
Combustion Stability ◽  
Absolute Pressure ◽  
Nox Emissions ◽  
Hcci Engine ◽  
Hcci Engines

This study investigates the effects of biogas composition on combustion stability for a purely biogas fueled HCCI engine. Biogas is one of the most promising renewable fuels for Combined Heat and Power systems driven by internal combustion engines. However, the high content of CO2 in biogas composition leads to low thermal efficiencies in spark ignited and dual fuel compression ignited engines. The study is divided into two parts: first experimental results on a biogas-fueled HCCI engine are used to validate a numerical model, and second the model is used to investigate how biogas composition impacts combustion stability. In the first part of the study, experimental analysis of a 4 cylinder, 1.9 L Volkswagen TDI Diesel engine running with biogas in HCCI mode has shown high gross indicated mean effective pressure (close to 8 bar), high gross indicated efficiency (close to 45%) and ultra-low NOx emissions below the US2010 limit (0.27 g/kWh). An inlet absolute pressure of 2 bar and inlet temperature of 473 K (200°C) were required for allowing HCCI combustion with a biogas composition of 60% CH4 and 40% CO2 on a volumetric basis. However, slight changes in inlet pressure and temperature caused large changes in cycle-to-cycle variations at low equivalence ratios and large changes in ringing intensity at high equivalence ratios. A numerical model is validated against these experimental results. In the second part of the study, the numerical results for varied biogas composition show that at high load limit, higher contents of CH4 in biogas composition allow advanced combustion and increased burning rates of the biogas air mixture. Higher contents of CO2 in biogas composition allow lowered ringing intensities with moderate decrease in the indicated efficiency and power output. NOx emissions are not highly affected by biogas composition, while CO and HC emissions tend to increase with higher contents of CO2. According with the numerical results, biogas composition is an effective strategy to control the onset of combustion and combustion phasing of HCCI engines running biogas, allowing more stabilized combustion at low equivalence ratios and safe operation at high equivalence ratios. The main advantages of using biogas fueled HCCI engines in CHP systems are the low sensitivity of power output and indicated efficiency to biogas composition, as well as the ultra low NOx emissions achieved for all tested compositions.

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