A Global-Local Emission-Model for NOx and Soot Emissions of Turbocharged CR-Diesel Engines

2010 ◽  
Author(s):  
Heiko Sequenz ◽  
Matthias Mrosek ◽  
Rolf Isermann
Keyword(s):  
Dynamic Models ◽  
Combustion Process ◽  
Batch Process ◽  
Emission Model ◽  
Model Quality ◽  
Engine Operation ◽  
Input And Output ◽  
Soot Emissions ◽  
Prediction And Simulation ◽  
Output Space

Stationary and dynamic models for the emissions of a CR-Diesel engine are developed using a global-local model approach. Results for the NOx and soot emissions are presented. All model inputs are measurable air path states and combustion parameters. They determine the emission formation before the combustion takes place. Therefore the model can be used for emission prediction and simulation. The combustion process is regarded as a batch process, such that the dynamics are introduced as external dynamics to the model via the inputs. Thus a stationary model structure can be applied. As the space of possible air path states varies widely for different engine operation points, several input and output transformations are given that linearize the input and output space. This improves the model quality and extends the operation range of the model. Modeling results are shown for stationary and dynamic data as well as for local and global model operation.

Application of a Phenomenological Model for the Engine-Out Emissions of Unburned Hydrocarbons in Driving Cycles

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Manuel Dorsch ◽  
Jens Neumann ◽  
Christian Hasse
Keyword(s):  
Phenomenological Model ◽  
Combustion Engine ◽  
Combustion Process ◽  
Formation Mechanisms ◽  
Emission Model ◽  
Engine Operation ◽  
Driving Cycles ◽  
Hc Emissions ◽  
Piston Crevice ◽  
Engine Map

In this work, the application of a phenomenological model to determine engine-out hydrocarbon (HC) emissions in driving cycles is presented. The calculation is coupled to a physical-based simulation environment consisting of interacting submodels of engine, vehicle, and engine control. As a novelty, this virtual calibration methodology can be applied to optimize the energy conversion inside a spark-ignited (SI) internal combustion engine at transient operation. Using detailed information about the combustion process, the main origins and formation mechanisms of unburned HCs like piston crevice, oil layer, and wall quenching are considered in the prediction, as well as the in-cylinder postoxidation. Several parameterization approaches, especially, of the oil layer mechanism are discussed. After calibrating the emission model to a steady-state engine map, the transient results are validated successfully against measurements of various driving cycles based on different calibration strategies of engine operation.

Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

2012 ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Diagnostic Tool ◽  
Combustion Process ◽  
Experimental Tests ◽  
Test Point ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Pressure Transducers ◽  
Rate Analysis ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

scholarly journals Thermodynamic cycles variability of TJI gas engine with different mixture preparation systems

2020 ◽  
Vol 181 (2) ◽  
pp. 46-52
Author(s):  
Filip SZWAJCA ◽  
Krzysztof WISŁOCKI
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Engine Operation ◽  
Gas Engine ◽  
Part Load ◽  
Mixture Preparation ◽  
Key Factor ◽  
Test Engine ◽  
Operation Stability ◽  
The Impact

Gas engines are a viable source of propulsion due to the ecological indicators of gas fuels and the large amount of the needed natural resources. Combustion of lean homogeneous gas mixtures allows achieving higher thermal efficiency values, which is a key factor in current engine development trends. Using the spark-jet ignition system (also called as Turbulent Jet Ignition or Two-stage combustion) significantly improves the efficiency and stability of the combustion process, especially in the part-load operation on lean or very lean mixtures. This paper presents the impact of using two different fuel injection methods: Port Fuel Injection or Mixer on the operation stability of a gas engine designed for LDVs. Comparative studies of two different mixture preparation systems were carried out on a single-cylinder AVL 5804 test engine. By re-cording the cylinder pressure for a significant number of engine cycles, it became possible to determine the repeatability of engine operation and to correlate the results with the mixture formation system and the air-fuel ratio. In the performed research the beneficial effect of the mixer system application on the engine operation stability in the part-load conditions was found.

scholarly journals Simulation Research of Aircraft Piston Engine Rotax 912

2019 ◽  
Vol 252 ◽  
pp. 05007 ◽  
Author(s):  
Łukasz Grabowski ◽  
Ksenia Siadkowska ◽  
Krzysztof Skiba
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Basic Unit ◽  
Piston Engine ◽  
Engine Operation ◽  
Simulation Research ◽  
One Dimensional ◽  
Operation Process ◽  
Model Aircraft

This paper reports the results of simulation works of Rotax 912 aircraft piston engine, which is a basic unit in most ultra-light aircrafts. The method for preparing the model aircraft engine operation process was presented. Simulation tests were carried out in the AVL Boost programme. The programme allows a full use of zero-dimensional and one-dimensional modelling. It also allows a comparison of other engine models. The developed model has enabled us to simulate the flow of air through the inlet pipes, carburettors, valves and combustion process. The preparation of the model required us to enter parameters that are not available in the manufacturer's catalogue, therefore, necessary measurements and analysis of the engine parts were carried out on a laboratory bench. The calculations in the AVL Boost programme were carried out in the conditions determined for the selected BMEP values with the objective of characterising the engine performance by determining its power, torque and fuel consumption.

scholarly journals Analytical Approach to the Exergy Destruction and the Simple Expansion Work Potential in the Constant Internal Energy and Volume Combustion Process

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 395
Author(s):  
Jeongwoo Song ◽  
Han Ho Song
Keyword(s):  
Internal Combustion Engine ◽  
Analytical Approach ◽  
Combustion Engine ◽  
Combustion Process ◽  
Internal Combustion ◽  
Thermodynamic System ◽  
Exergy Destruction ◽  
Engine Operation ◽  
System Temperature ◽  
Simple Expansion

The exergy destruction due to the irreversibility of the combustion process has been regarded as one of the key losses of an internal combustion engine. However, there has been little discussion on the direct relationship between the exergy destruction and the work output potential of an engine. In this study, an analytical approach is applied to discuss the relationship between the exergy destruction and efficiency by assuming a simple thermodynamic system simulating an internal combustion engine operation. In this simplified configuration, the exergy destruction during the combustion process is mainly affected by the temperature, which supports well-known facts in the literature. However, regardless of this exergy destruction, the work potential in this simple engine architecture is mainly affected by the pressure during the combustion process. In other words, if these pressure conditions are the same, increasing the system temperature to reduce the exergy destruction does not lead to an increase in the expansion work; rather, it only results in an increase in the remaining exergy after expansion. In a typical internal combustion engine, temperatures before combustion timing must be increased to reduce the exergy destruction, but increasing pressure before combustion timing is a key strategy to increase efficiency.

Realization of a Fully Optically Accessible Medium Speed Large Bore Engine Using a Fisheye Optic

2020 ◽  
Author(s):  
Stephan Karmann ◽  
Christian Friedrich ◽  
Maximilian Prager ◽  
Georg Wachtmeister
Keyword(s):  
High Speed ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Combustion Process ◽  
Engine Operation ◽  
New Approach ◽  
Medium Speed ◽  
Starting Point ◽  
Nominal Load ◽  
Fire Engine

Abstract To address one of the main environmental concerns, the engine out emissions, an enhanced understanding of the combustion process itself is fundamental. Recent optical and laser optical measurement techniques provide a promising approach to investigate and optimize the combustion process regarding emissions. These measurement techniques are already quite common for passenger car and truck size engines and significantly contribute to their improvement. Transferring these measurement techniques to large bore engines from low to high speed is still rather more uncommon especially due to the bigger challenges caused by the engine size and thus much higher stability requirements and design effort for optical accessibility. To cover this new field of research a new approach for a medium speed large bore engine was developed using a fisheye optic mounted centrally in the cylinder head to design a fully optically accessible engine test bench. This new approach is detailed with a test setup layout and a stability concept consisting of cooling systems and the development of a suitable operation strategy based on simulation and experimental verification. The design of this single cylinder engine with 350mm bore and 440mm stroke providing 530kW nominal load at 750 rpm was tested up to 85% nominal load in skipped fire engine operation mode. The measurements of the flame chemiluminescence of a dual fuel combustion of the diesel gas type present proof of the feasibility of the new design as a starting point for future systematic studies on the combustion process of large bore engines.

scholarly journals Research on combustion process of gasoline homogenous charge compression ignition engine

2018 ◽  
Vol 184 ◽  
pp. 01013
Author(s):  
Corneliu Cofaru ◽  
Mihaela Virginia Popescu
Keyword(s):  
Experimental Research ◽  
Fuel Injection ◽  
Combustion Process ◽  
Fuel Mixture ◽  
Spark Ignition Engine ◽  
Injection System ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Homogenous Charge Compression Ignition

The paper presents the research designed to develop a HCCI (Homogenous Charge Compression Ignition) engine starting from a spark ignition engine platform. The chosen test engine was a single cylinder, four strokes provided with a carburettor. The results of experimental research data obtained on this version were used as a baseline for the next phase of the research. In order to obtain the HCCI configuration, the engine was modified, as follows: the compression ratio was increased from 9.7 to 11.5 to ensure that the air – fuel mixture auto-ignite and to improve the engine efficiency; the carburettor was replaced by a direct fuel injection system in order to control precisely the fuel mass per cycle taking into account the measured intake air-mass; the valves shape were modified to provide a safety engine operation by ensuring the provision of sufficient clearance beetween the valve and the piston; the exchange gas system was changed from fixed timing to variable valve timing to have the possibilities of modification of quantities of trapped burnt gases. The cylinder processes were simulated on virtual model. The experimental research works were focused on determining the parameters which control the combustion timing of HCCI engine to obtain the best energetic and ecologic parameters.

Shaping the Combustion Chamber of a Piston Engine with Direct Injection of Gasoline

2019 ◽  
pp. 67-76
Author(s):  
R.Z. Kavtaradze ◽  
A.A. Kasko ◽  
A.A. Zelentsov
Keyword(s):  
Combustion Chamber ◽  
Direct Injection ◽  
Combustion Process ◽  
Three Dimensional ◽  
Numerical Control ◽  
Engine Operation ◽  
Model Fuel ◽  
Nonstationary Equations ◽  
Current Lines ◽  
Control Volumes

The object of the study was a six-cylinder in-line engine for land transport system with direct gasoline supply and forced ignition. The problem of shaping the combustion chamber is solved using the numerical control volumes method in a three-dimensional formulation. Nonstationary equations of energy, motion, diffusion and continuity in the Reynolds form, supplemented by the k-ζ-f model of turbulence, are used as a basis for modelling the engine operation. To model fuel combustion, an extended coherent flame model (ECFM) was used. Calculations were performed using the AVL FIRE software. The processes of mixture formation were optimized by considering the current lines and velocity fields of a moving charge, taking into account the geometry of the combustion chamber and intake and exhaust ports. As a result, the efficiency of the engine increased and the combustion process became more stable in the part load modes employing different fuel supply laws.

A Study of Combustion Inefficiency in Diesel LTC and Gasoline-Diesel RCCI via Detailed Emission Measurement

2014 ◽  
Author(s):  
Shouvik Dev ◽  
Prasad Divekar ◽  
Kelvin Xie ◽  
Xiaoye Han ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Combustion Process ◽  
Speciation Analysis ◽  
Ratio Test ◽  
Emission Measurement ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Engine Operation ◽  
Incomplete Combustion ◽  
Production Of Hydrogen

Reduction of engine-out NOx emissions to ultra-low levels is facilitated by enabling low temperature combustion (LTC) strategies. However, there is a significant energy penalty in terms of combustion efficiency as evidenced by the accompanying high levels of hydrocarbon (HC), carbon monoxide (CO), and hydrogen emissions. In this work, the net fuel energy lost as a result of incomplete combustion in two different LTC regimes is studied. The first LTC strategy, partially premixed compression ignition (PPCI), is investigated using a single, high pressure, in-cylinder injection of diesel fuel along with the application of exhaust gas recirculation (EGR). The second strategy includes dual-fuel application – reactivity controlled compression ignition (RCCI) of port injected gasoline and direct injected diesel. Moderate to high levels of EGR are necessary during engine operation in either of the two LTC pathways. A detailed analysis of the incomplete combustion products was conducted while the engine was operated in the aforementioned LTC modes. Speciation analysis of hydrocarbons was performed by sampling the exhaust gas in an FTIR. The total HC and the CO emissions were simultaneously measured using an FID and an NDIR, respectively. The production of hydrogen during the combustion process was also evaluated using a mass spectrometer. Engine tests were conducted at a baseline load level of 10 bar IMEP in the PPCI and RCCI modes. Load extension tests, up to 17 bar IMEP, were then conducted in the RCCI mode by increasing the gasoline-to-diesel fuel ratio. Test results indicated that CO, H2, and light HC made up for most of the combustion in-efficiency in the PPCI mode while heavier HC and aromatics were significantly higher in the RCCI mode.

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