# Advanced Simulation Techniques for IC Engines

## Presentation on theme: "Advanced Simulation Techniques for IC Engines"— Presentation transcript:

Advanced Simulation Techniques for IC Engines
ASTICE Advanced Simulation Techniques for IC Engines

Application CFD- 3D general flow analysis
CFD- 3D Compressible flow analysis Hydraulic System simulation Control System Analysis Map Based simulation 1D general Flow Analysis- utility design CFD- 3D Combustion and Emission analysis Engine Cycle Simulation Cooling circuit simulation Fuel Injection System Analysis Driveline Simulation CFD- 3D general flow analysis

Engine Cycle Simulation
Combustion Model Weibe function Model Multi-zone spray Model Two-Zone knock model for SI and DF engine Gas exchange Model 1D gas dynamic model Turbocharger Matching Optimization Model RSM model with DOE Optimization Using Genetic Algorithm

Engine Cycle Simulation-Case 1
Fit Weibe function Generate Model Single Cylinder Complete Engine Cycle Run the model Weibe combustion model

Engine Cycle Simulation-Case 1
Single DI Weibe Start of combustion Crank angle at 1% burned Combustion Duration & Weibe exponent Calculated by non-linear least square method Weibe combustion model Fit Weibe function to experimental or CFD heat release Start of combustion Crank angle at 0.5% burned Multiple DI Weibe Premixed fraction, Premixed combustion duration , premixed Weibe exponent, mixing controlled combustion duration and mixing controlled Weibe exponent Calculated by non-linear least square method

Engine Cycle Simulation-Case 1
Weibe combustion model Fit Weibe function Single Weibe Model SOC = -5.3 Θd = 63.5 M = 0.96 Multiple Weibe Model SOC = -4.1 Pf = 0.1 Θd_p = 12 Mp = 0.5 Θd_p = 60 Mp = 1.15

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Model Generation Single Cylinder Model Complete Engine Cycle

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Single cylinder Model Inputs Valves Effective Area Weibe Function & Fuel Combustion properties Ignition delay Calculation Steady State Wall Temperatures Heat Transfer Model In-Cylinder Geometry Emission Model (NOx only) Single Cylinder Model Outputs In-Cylinder Pressure & temperature IMEP, ISFC, indicated efficiency NOx generation Heat transfer Data

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Single cylinder Model

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Single cylinder Model Single Cylinder results Zoom

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Single cylinder Model Single Cylinder results Scavenging

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Single cylinder Model Single Cylinder results Fuel Energy 196.8 kW Indicated Power 99.6 kW IMEP=25 bar Indicated Efficiency= 50.6% Heat transfer to walls 19.6 kW 6.7 kW from Gas to Liner 6.4 kW from Gas to Head 6.5 kW from Gas to Piston Exhaust Energy 77.6 kW A fraction is recovered through turbocharger in multi cylinder engine

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Complete Engine Cycle Single Cylinder Model Firing Order/ No. Cylinders TC and IC model Filling & Emptying Model Friction Model

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Complete Engine Cycle Filling & Emptying Model

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Complete Engine Cycle Gas Exchange Diagram Filling & Emptying Results

Engine Cycle Simulation-Case 1
Weibe combustion model Model Generation Complete Engine Cycle Filling & Emptying Model Results Ambient Temp (°C) 25 I/C Water Temp (°C) 33 Power (kWb) 500 Speed (r/min) 1500 BMEP (bar) 21 BSFC (g/kWh) 199 BSAC (kg/kWh) 6.56 Firing Pressure (bar) 170 Boost Pressure Ratio 3.05 Compressor Exit Temp (°C) 171 Air Manifold Temp (°C) 48 Compressor Eff. (%) 76 Turbocharger Eff. (%) 58.5 Surge Margin (%) 26 Exh M’fold Temp Energy Mean (%) 516 Turbine Inlet Temp (Estimated) (°C) 575 Trapped A/F Ratio 25.5:1 Compressor Raw Map Turbine Raw Map

Engine Cycle Simulation-Case 2

Engine Cycle Simulation-Case 2
Multi-zone spray Model for Diesel combustion Main code Discharge Coefficient Routine Spray Penetration Routine Droplet Evaporation Routine Sauter Mean Diameter Routine Air Entrainment Routine Heat transfer Routine

Engine Cycle Simulation-Case 2
Multi-zone spray Model for Diesel combustion Start of Combustion Premixed combustion Temperature Distribution in Spray Zones

Engine Cycle Simulation-Case 2
Multi-zone spray Model for Diesel combustion Peak heat release rate Combustion tale Temperature Distribution in Spray Zones

Engine Cycle Simulation-Case 2
Multi-zone spray Model for Diesel combustion NOx & SOOT Fuel evaporation & Burn

Engine Cycle Simulation-Case 2
Multi-zone spray Model for Diesel combustion Pressure & Temperature Normalized Fuel Injection, Evaporation, Burn and Heat release rate

Engine Cycle Simulation-Case 3
Two-Zone knock model for SI and DF engine The pilot fuel (DF)/Spark (SI) is considered as ignition initiator The heat released via diesel fuel is entered to model as Weibe function in DF engines The ignition delay is calculated from Arrhenius formula The air and natural gas mixture will be divided into two zones as soon as combustion starts The burned zone consists of reacting species and combustion products. It is assumed that all of species are in thermodynamic equilibrium

Engine Cycle Simulation-Case 3
Two-Zone knock model for SI and DF engine The Burned Zone The Unburned Zone CO CO H2O H2O CHO O CH4 O2 HO2 CO2 O2 N2 OH H2O2 CH3 OH N2 H H2 H CH2O Thermodynamic Equilibrium Chemical Kinetics Heat Release Auto-ignition  Knock

Engine Cycle Simulation-Case 3
Two-Zone knock model for SI and DF engine

Engine Cycle Simulation-Case 3
Two-Zone knock model for SI and DF engine Model Validation Continuous lines : Two-Zone model results Points : CAT Engine simulation results (SAE paper)

Engine Cycle Simulation- Case 4
1D gas dynamic model Significant error at high speeds Instability at low speeds and load Gas Dynamic modeling 1D CFD Complex program Better Results Filling & Emptying Modeling

Engine Cycle Simulation- Case 4
1D gas dynamic model Two-Step lax-Wendroff method Flow Limit Function

Engine Cycle Simulation- Case 4
1D gas dynamic model

Engine Cycle Simulation- Case 5
Turbocharger Matching Criteria for turbo matching Application Requirement Marine Maneuvering Rail Traction Load acceptance Transient operation Turbo lag Compressor Surge Steady State Condition High efficiency Stable Conditions

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation Load Increase Process

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 150 Sec Ramp of Throttle from Transient Response

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 150 Sec Ramp of Throttle from Transient Response

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 40 Sec Ramp of Throttle from Transient Response

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 40 Sec Ramp of Throttle from Transient Response

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 12 Sec Ramp of Throttle from Transient Response

Engine Cycle Simulation- Case 5
Turbocharger Matching/ Transient operation 12 Sec Ramp of Throttle from Transient Response

Optimization Process RSM Methodology Design of Experiments
Running the Simulation Results Processed at Polynomial Surfaces Optimization via Genetic Algorithm RSM Methodology

Optimization Model- RSM
Mathematical and statistical technique for empirical model building The objective is to optimize a response changes in the input variables identifies the changes in the output response The RSM is used to design optimization is reducing the cost of expensive methods The Approximation model function is generally polynomial

Optimization Model- DOE
An experiment is a series of tests or simulations, called runs The objective of DOE is the selection of the points where the response should be evaluated Optimal design of experiments are associated with the mathematical model of the process The choice of the design of experiments have an influence on the accuracy of the approximation

Optimization Model- DOE Methods
Box and Dropper Latin Hypercube D-Optimum Full Factorial Increase in Level of Accuracy Increase in Run time

Optimization Example 1 Injection timing VS Speed & fuel amount
Response Surfaces

Optimization Example 1 Injection timing VS Speed & fuel amount
Optimized Map

Cooling circuit simulation
1D CFD analysis of Flow Simple and Extended model of Heat exchanger Coupled Solution with Engine Cycle Simulation Transient Simulation Extended Model of Water pump

Cooling circuit simulation-Case 1
Simple and Extended model of Heat exchanger Simple Model Inside HX Volume of Fluid Pressure drop across HX Effectiveness of HX Outside flow rate Outside temperatre

Cooling circuit simulation-Case 1
Simple and Extended model of Heat exchanger Extended Model Inside Flow Volume of Fluid Pressure drop across HX Flow rate Nu correlation Outside Flow Effectiveness type Wall Absorb Wall material spec Wall volume

Cooling circuit simulation-Case 1
Simple and Extended model of Heat exchanger Simple Model Acceptable results for cross flow HXs Reliable for air cooled radiators and condenser Extended Model More accurate model Rely on experimental data

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Engine Model Cooling Circuit Model Heat transfer BCs Heat Rejection

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Operation of the engine

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Operation of the engine

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Thermal Results- Coolant inside head drillings

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Thermal Results- Coolant inside Cylinder jackets

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Thermal Results- HTC Coolant to liner

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Thermal Results- average Liner wall temperature Coolant Side

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Transient Thermal Results- HTC Coolant to head

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model To head To Liner- Top To Liner- Bottom Transient Thermal Results- average In-Cylinder Gas temperature

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model To Liner- Top To head To Liner- Bottom Transient Thermal Results- average In-Cylinder HTC

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Correlated Thermal Results- average In-Cylinder HTC

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Correlated Thermal Results- average In-Cylinder HTC

Cooling circuit simulation-Case 2
Coupled Solution with Engine Cycle Simulation/ Transient/ Extended pump model Correlated Thermal Results- average In-Cylinder HTC

1D general Flow Analysis- utility design
Combined Heat & Power Generation

Control System Analysis-Case 1
Waste-gate Control

Control System Analysis-Case 2
Throttle Control

Driveline (Map Based) simulation

Driveline (Map Based) simulation

Driveline (Map Based) simulation-Example
UIC Performance test simulation

CFD- 3D general flow analysis
3D Flow Through oil jet

CFD- 3D general flow analysis
2D flow through gas throttle Valve

CFD- 3D general flow analysis
2D flow through gas throttle Valve

CFD- 3D general flow analysis
2D flow through gas throttle Valve

CFD- 3D general flow analysis
2D flow through gas throttle Valve

CFD- 3D Compressible flow analysis
Flow through Modular Pulse Convertor Exhaust

CFD- 3D Compressible flow analysis
Flow through Modular Pulse Convertor Exhaust

CFD- 3D Compressible flow analysis
Flow through Modular Pulse Convertor Exhaust

CFD- 3D Compressible flow analysis
Flow through Modular Pulse Convertor Exhaust

CFD- 3D Compressible flow analysis
Flow through Modular Pulse Convertor Exhaust

CFD- 3D Compressible flow analysis

CFD- 3D Compressible flow analysis

CFD- 3D Compressible flow analysis