Understanding of SI & CI engine After treatment device by GT-POWER

Title : Understanding of SI & CI engine Aftertreatment device

Objective :  1. Explore Detailed SI engine+aftertreatment 

                  2. Explore Detailed CI engine aftertreatment 

                  3 .Compare results of all cases 

 

1. CI engine + after treatment model

                         This example demonstrates an integrated model with detailed engine and detailed aftertreatment system running one steady-state operating point. The detailed engine model comes from the Diesel_WGController example in the Engine Performance directory. The detailed aftertreatment system is a combination of the DOC_Sampara_and_Bissett and SCR_Fe_Zeolite example models along with a DPF setup.

CI Engine 

Engine Cranktrain

           

Cylinder Geommetery 

             

Emission turn ON

SOOT emission

  Properties of SOOT    

NOx Model

                      

NOx model

                  

Heat Transfer model

              

Fuel Injector 

               

Injection time

                     

Turbine 

                        

Compressor

                           

Wastegate controller

                       

Assembly 24

Fuel Conversion:

The fuel converter converts unburned fuel emitted from the cylinders to representative hydrocarbons used in the aftertreatment reaction mechanisms. The converter works by considering a balanced reaction of fuel and excess water vapor and converting to the smaller hydrocarbons with a small amount of generated oxygen.

The generated hydrocarbons seen by the aftertreatment system must be assumed by the user. In this example, it is assumed that each mole of unburned fuel breaks down into 50% fast-oxidizing HCs represented by C3H6, and 50% slow-oxidizing HCs, on a C3 basis. Of the slow-oxidizing HCs, it is assumed 50% of them are adsorbable and 50% are non-adsorbable, on a C3 basis. These percentages are on a molar basis.

50% C3H6 (fast-oxidizing HC)
25% diesel-vap-ads (adsorbable, slow-oxidizing HC)

Assembly sense the combustion by product from the cylinder & coverts in to average concentration in one cycle & send to the Quasi-steady state after treatment circuit

 

Cycle average template take the data of diffrent species from cylinder & convert in to average cycle send it to output singal

                

Output from cycle average send to the Quasi-steady inlet

DOC model Explicit

Input signal send to DOC-Explicit

           

Outlet temprature DOC -Quasi steady state sens to the  DOC -explicit

DOC -Quasi steady state

 

      

DOC -QS is the detailed model where we can the washcoat material & its thickness.

Convergence efficiency model

                                       

DOC Monitor

DPF-Explicit

The filter models three physical processes of a wall-flow particulate filter:

1) pressure drop

2) particulate matter (soot) and ash filtration

3) soot regeneration and catalytic reactions

Pressure drop in DPF -QS is send to the DPF Explicit

            

DPF-QS Model

Name of the ' Filtration' reference object that describes the particulate matter filtration and loaded filter pressure drop model. The ' Filtration' reference object has the options for modeling soot filtration in the substrate wall, soot cake layer, ash layer, pore diffusion through the layers, and the particle number distribution model.

This template specifies catalytic surface reaction kinetics that require the modeling of storage or coverage. It is similar to 'GlobalReactions' template in that the rate constants are assumed to obey the modified Arrhenius' law and the concentration expression can be arbitrarily specified.

DPF Monitor

                                     

Input data soot mass & substrate temprature send to convegence montor 

SCR-explicit

SCR-QS

SCR Chemical Reaction library

Input species to SCR

             

Input Reaction to SCR

SCR- Convergence monitor

                        

This template is used to monitor instantaneous signals or Time RLTs (only wirelessly) during a simulation. The 'MonitorSignal' can operate in different modes, depending on the setting of X-Axis Type.

Urea injection 

                           

Urea injection diffrent properties

                   

Urea injection in liquid form

                 

   

 

Urea Decomposition

                                   

Urea control Technology 

in the urea control technology its very important to maintain the urea injection rate otherwise excess urea injection will lead to NH3 slip.

                                       

NO & NO2 Input signal send to Urea control Technology 

its very important to maintain NO & NO2 species because help to conversion of NOx in to NH3 & N2

   

Tempraure signal to Urea control technology 

                           

NH3 slip Signal send to urea control technology 

                 

Urea control Technology model

 

Case setup

In case setup to see the effect of injection timing on emission , there is vary the injection time from -4,-2,2,4 

Engine geommetery 

Engine Performance 

• for advanced injection timing brake power is increased due to more time get to burn the fuel but for late injection timing brake power redced due to not get it much time to burn the fuel.
• Also its found that for advanced injection timing less BSFC is lower , while advanced injection time BSFC is higher.

Emission comaprison

• Advanced ignition timing increase the Brake power but increase the NOx, CO emission 
• Late ignition timing decrease the Brake power but decrease the  NOx, CO emission 

Conversion efficiency of DOC at cycle 1 

SOOT Mass retaination 

SCR Monitor signal at cycle1

 

SI Engine +Aftertreatment model

• This example demonstrates modeling an SI engine combined with a detailed TWC in a secondary aftertreatment circuit.
• The original base model SI_4cyl_EGRController was combined with the aftertreatment example model TWC_Ramanathan_and_Sharma, which uses a published reaction mechanism for a passenger car TWC.
• A secondary circuit is used to solve the reactions using the quasi-steady (QS) flow solver, which is able to use a large master time step so that it does not restrict the computation time

Inlet environement

This template describes boundary conditions of pressure, temperature, and fluid properties. There are options to include effects of altitude and humidity

                 

Flow split T-Right

         This template models a 90° T-junction with cylindrical cross-section. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

      

Reasonator pipe

This template models a pipe with a round cross-section and an optional bend. Data entered to describe the bend will be used to automatically calculate the pressure loss coefficients that account for the associated head losses.

FlowSplitSphere

This template models a spherical-shaped flow volume. It often has more than 2 flow ports, and acts to split flow; however, it is not required to have more than 2 ports. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

           

PipeRound - Pipe with Circular Cross-Section and Optional Bend  (Air- BOX IN)

This template models a pipe with a round cross-section and an optional bend. Data entered to describe the bend will be used to automatically calculate the pressure loss coefficients that account for the associated head losses

               

OrificeConn - Orifice/Restriction Between Two Flow Components

This template models an orifice, defined by diameter or area and discharge coefficients, which calculates the mass flow rate between the adjacent flow volumes. 'OrificeConn' parts represent the plane connecting two flow components. The momentum equation, as shown in the Flow Manual, is solved to calculate the flow rate through the orifice.

             

FlowSplitGeneral - Flow Volume with General Geometry (Air- BOX Out)

This template models any arbitrarily shaped flow volume. It often has more than 2 flow ports, and acts to split flow; however, it is not required to have more than 2 ports. This template contains inputs for geometry at each of the ports, enabling the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

 

Boundry Data

           

ThrottleConn - Connection

This template describes a throttle placed between two flow components. The user imposes or controls the throttle angle, from which the effective area of the throttle is looked up and imposed. This template is typically only used when measured discharge coefficient data is available from a flow bench test.

When discharge coefficient data is not available, an 'OrificeConn' part adjusted for the pin size can be used instead of a ThrottleConn. For wide open throttle operation only, this throttle pin typically occupies about 15% or more of the throttle body area. Set the orifice diameter so that its area equals the area of the wide-open throttle, and set the discharge coefficients to 1.0. The equivalent orifice diameter can be found by the following equation:

    

Dequivalent = Equivalent diameter of the wide-open throttle

Dthrottle = Diameter of the throttle body

T = Thickness of the wide-open throttle vane and pin

 

                           

FlowSplitTAngle - Tee Junction with Arbitrary Branch Angle

This template models a T-junction, with the "tee" at any angle, with cylindrical cross-section. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

                          In this Tee junction there is addition of Exhaust gas through the EGR valve

 FlowSplitTRight - Tee Junction with 90° Branch Angle

This template models a 90° T-junction with cylindrical cross-section. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

 

FlowSplitY - Y Junction with Symmetric Branch Angle

This template models a Y-junction with cylindrical cross-section. This flowsplit configuration assumes the two branch legs have branch angles that are symmetric about the centerline of the main branch. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

Fuel -Air mixture

Fuel- Injector

This template is used for the operation of a sequential pulse fuel injector, most commonly in SI engines. The user imposes the fuel-to-air ratio, and the resultant injection pulse width is calculated for each injection event. This injector should be used for all engine simulations for which the fuel is pulse injected with an imposed air-to-fuel ratio.

Engine- Cylinder 

This template is used to specify the attributes of engine cylinders. Note that cylinder geometry is specified in the EngineCrankTrain.

Wall temprature

EngCylHeatTr - Cylinder Heat Transfer Model

This template is used to calculate heat transfer from 'EngCylinder', 'PistonCylinder' or 'EngCrankcase' parts

EngCylCombSIWiebe - SI Wiebe Combustion Model

This template imposes the combustion burn rate for spark-ignition engines using a Wiebe function. It can be used with any type of injection. If at any instant the specified cumulative combustion exceeds the specified injected fuel fraction for a direct-injected SI (DISI) engine, the combustion rate will be limited by the amount of fuel available.

Engine & Cranktrain

FlowSplitY - Y Junction with Symmetric Branch Angle

This template models a Y-junction with cylindrical cross-section. This flowsplit configuration assumes the two branch legs have branch angles that are symmetric about the centerline of the main branch. The geometry information enables the solution to calculate effects of expansion/contraction, port angles, and characteristic lengths for wave travel time. See the Flow Modeling Theory Manual for information and recommendations for modeling with flowsplits.

Volume of flowsplit. Setting to "def" will assume a cylindrical volume for the flowsplit, V, via the following relation:

                                                     

where the flowsplit length, L, and diameter of the main leg, D, 

Wall External Boundary Conditions Object

EGR Controller

ControllerEGRValve - EGR Valve Controller

This template contains a model-based controller used to target EGR rate by controlling throttle angle or an orifice diameter. Throttle angle output is used to actuate a 'ThrottleConn' part, while orifice diameter output is used to actuate an 'OrificeConn' part. This template is only designed to be used in Periodic simulations (as determined by TimeControl folder in RunSetup).

INPUT TO EGR CONTROLLER

INPUT FROM EGR-VALVE TO EGR CONTROLLER

Output to EGR VALVE  To open the EGR VALVE Diameter

EGR VALVE 

Exhaust pipe 

This template models a pipe with a round cross-section and an optional bend. Data entered to describe the bend will be used to automatically calculate the pressure loss coefficients that account for the associated head losses.

Run setup 

Setup is run by two method

1. Expicit engine circuit 2. Quasi-steady Aftertreatment circuit

1. Explicit engine circuit

for operate the explicit engine circuit input signal taken from the Quasi-steady Aftertreatment circuit 

MonitorSignal - Instantaneous Signal Run-Time Monitor

This template is used to monitor instantaneous signals or Time RLTs (only wirelessly) during a simulation. The 'MonitorSignal' can operate in different modes, depending on the setting of X-Axis Type.

There is main aim to monitor the Three way catalytic temprature

Input signal to TWC monitor

 

 Catalytic converter

This template represents a flow-through catalyst or a packed bed reactor. Chemical reactions that occur in the catalyst brick may be modeled by attaching a *Reactions part to the 'CatalystBrick', typically 'SurfaceReactions', which can be found in the Exhaust Aftertreatment section of the Template Library.

2. Quasi-steady Aftertreatment circuit

for run the quasi -steady after treatment ciruit its very important to take input signal of diffrent species from exhasust manifold. 

Input signal to QS Solver

There is input given to QS is 

1. Exhasut Mass flow rate 2.  Exhaust Temprature 3. Species O2 

4.CO2 Species     5. H2O Species 6. COSpecies  7. N02 Species 8. NO Species  9. H2 Species 10. Fuel vapour

11. Fuel Liquid

                                   

exhaust mass flow rate input 

exhaust temprature 

Species O2 

Unburnt Liquid +Vapour (Unburnt fuel) is react with O2

                       Formula=O2in+Fuel*0.5293

Species CO2 

H2O Species

Unburnt fuel Liquid +Vapour from that H20 mol is reduced & send to input signal 

 

CO Signal

H2 Signal 

NO Signal 

NO2 Signal

Vaporize unburnt fuel

Liquid unburnt fuel

vapour fuel  convert to CalcC3H6 fuel

Formula =Fuel*2.6433*0.8

Liquid fuel convert to CalcC3H8 fuel

=Fuel*2.6433*0.2

Quasi -Steady Circuit

 TWC operate on Quasi -steady circuit

TWC Surface Reaction data

Montitor the Oxygen in Exhaust manifold with Lambda Sensor

                               

Input Signal for O2 

1. Lambda Explicit Engine Circuit

2. Lambda form QS Aftertreatment circuit

3. O2 Stoarage

Conversion Efficiency of diffrent species monitor 

                               

                                   

Input signal from exhaust pipe to conversion efficiency monitor

Input Signal

1. CO   2. HC   3. N0    4. H2  5. Inlet Temp   6. Substrate Temp

After final calculation Six Output signal given by Mathamatical calculator to Conversion Eff. Monitor

Back Pressure Signal from Explicit Engine circuit to QS Circuit Environement Outlet  

                                             

Case Setup 

Case setup made for analyze the effect of Air- Fuel Ratio on emission Parameters 

Air-Fuel Ratio 1) 14:1               2) 14.5:1                       3) 15:1

Run Time plot 

Engine Geometry 

Engine Performance 

1. For rich A/F ratio 14:1 higher Brake power (44.7KW), Brake Torque (142.2N-m) but there is higher BSFC (251.9g/Kw-h).

2. For rich A/F ratio 14.5 :1 middle  Brake power (44.4KW), Brake Torque (141.3N-m) but there is lesser  BSFC (251.9g/Kw-h) compare with rich A/F

3. For rich A/F ratio 15 :1 lesser Brake power (43.45KW), Brake Torque (138.6N-m) but there is lesser  BSFC (240.9g/Kw-h) compare with rich A/F

Emission Parameters

1. For rich A/F ratio 14:1 lesser Nox emission (1667.66ppm) due to lesser N2 content in A/F mixture, Higher HC emission (76.66ppm) due to rich mixture higher content of Carbon atoms, higher CO emisson(21666.8) due rich mixture less percentage of Oxygen content. 

2.For rich A/F ratio 14.5:1 Higher Nox emission (2276.89ppm) due to higher N2 content in A/F mixture, Higher HC emission (74.75ppm) due to lean mixture lesser content of Carbon atoms, lesser CO emisson(11237.3ppm) due stochiometric ratio maintain

 3.For rich A/F ratio 15:1 Higher Nox emission (2810.25ppm) due to higher N2 content in A/F mixture, lesser HC emission (72.72ppm) due lean mixture lesser content of Carbon atoms, higher CO emisson(1841.74ppm) due to excessive lean mixture.

 Conversion effiiciency 

Lambda Monitor

TWC Exhaust gas Temprature monitor 

Overall Conclusion 

CI Engine with Exhaust After Treatment 

1. for advanced injection timing brake power is increased due to more time get to burn the fuel but for late injection timing brake power redced due to not get it much time to burn the fuel.

2. Also its found that for advanced injection timing less BSFC is lower , while advanced injection time BSFC is higher.

3.Advanced ignition timing increase the Brake power but increase the NOx, CO emission 

4. Late ignition timing decrease the Brake power but decrease the  NOx, CO emission 

SI Engine with Exhaust After Treatment 

1. For rich A/F ratio 14:1 higher Brake power (44.7KW), Brake Torque (142.2N-m) but there is higher BSFC (251.9g/Kw-h).

2. For rich A/F ratio 14.5 :1 middle  Brake power (44.4KW), Brake Torque (141.3N-m) but there is lesser  BSFC (251.9g/Kw-h) compare with rich A/F

3. For rich A/F ratio 15 :1 lesser Brake power (43.45KW), Brake Torque (138.6N-m) but there is lesser  BSFC (240.9g/Kw-h) compare with rich A/F.

4. For rich A/F ratio 14:1 lesser Nox emission (1667.66ppm) due to lesser N2 content in A/F mixture, Higher HC emission (76.66ppm) due to rich mixture higher content of Carbon atoms, higher CO emisson(21666.8) due rich mixture less percentage of Oxygen content. 

5.For rich A/F ratio 14.5:1 Higher Nox emission (2276.89ppm) due to higher N2 content in A/F mixture, Higher HC emission (74.75ppm) due to lean mixture lesser content of Carbon atoms, lesser CO emisson(11237.3ppm) due stochiometric ratio maintain

 6.For rich A/F ratio 15:1 Higher Nox emission (2810.25ppm) due to higher N2 content in A/F mixture, lesser HC emission (72.72ppm) due lean mixture lesser content of Carbon atoms, higher CO emisson(1841.74ppm) due to excessive lean mixture.