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MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 1
Firing Order Optimization Based on Integrated Simulation
Jürgen KnorrThomas MalischewskiJoachim Weiß
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 2
Outline
Introduction
Motivation
Standard and advanced Approach to Dimensioning of Crankshaftsand Bearings
Basic Structure of Integrated Models
Verification of GT-SUITE Simulation Results by Experiments
Procedure for Finding suitable Firing Orders
Results of a new Firing Order for a V8-Engine
Summary
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 3
MAN EnginesProducts of MAN Nutzfahrzeuge, Nuremberg
Product Family of V-Engines at
MAN Nutzfahrzeuge: V8 – V10 – V12Gas V-EnginesPower Range 265 – 440 kW
Diesel V-EnginesPower Range 662 – 1324 kW
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 4
Motivation: Irregular Cylinder Pressures(V8 Gas-Engine)
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 5
Gas Exchange Phenomena
Opening Phases of the Exhaust Valves
0 180 360 540 720 900
1
2
3
4
5
6
7
8
Cyl
ind
er
Crank Angle
Internal EGR Rate (calculated):Cyl. 5) 5.61 % Cyl. 6) 3.84 %
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 6
Standard Approach to Dimensioning of Crankshafts and Bearings
The Cylinder Pressure Curve is determined throughMeasurement or Simulation
The mechanical Computation is run with the singlePressure Curve applied to all Cylinders
Separate and specialized Program Codes are used
Independent Cylinder Behaviour is not taken into account
Example: FEM-Model, Oscillation at the5th Eigen-Frequency
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 7
Advanced Approach to Dimensioning of Crankshafts and Bearings
Application of a Single Program Code: GT-SUITE
Building of an Integrated Model (Thermodynamics and Mechanical Dynamics)
Calibration of the Model with Experimental Data
Analysis allowing for Independent Cylinder Behaviour
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 8
Example ModelD2868 Yacht Engine
Complete Air Path with Compressors and Coolers
Detailed Combustion Model
Exhaust Piping with Turbines
Crankshaft
Damper
Flywheel
BrakeCardan Shaft
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 9
Advantages of Integrated Simulation
Application of a single Program Code and Model
Eliminates need for large data transfer operations
Reduces Iteration Loops and Computation Time
Minimises Errors owing to Data ExchangeMore comprehensive Results (incl. uniform Charge Air Distribution)
More cost-effective
Consideration of irregular Charge Air Distribution improves Predictions:
Maximum torsional Wear of the CrankshaftBearing Forces
Power Consumption of the torsional Damper
(These Values may differ even at uniform Cylinder Power, because of different Pumping Work
Fractions)
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010
GT-SUITEInput Data of a Crankshaft Model
GT-SUITE REFERENCE MANUALfor MECHANICAL LIBRARY TEMPLATES CrankTrain / Camshaft Group
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 11
Torsional TorquesTest Equipment of a V12 Engine
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 12
Torsional TorqueRun-Up of a V12 Engine, Experimental Results
Engine Speed
Signal (Torque)
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 13
Torsional TorquesRun-Up of a V12 Engine
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 14
Crankshaft Twisting Angle6-Cylinder In-Line-Engine
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 15
Crankshaft Twisting Angle6-Cylinder In-Line-Engine
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010
All Possibilities = 7! , which amounts to 5040
The theoretical Number of potential firing orders is reduced bycertain constraints (e.g. the Cylinders at one Crank have a fix IgnitionInterval)
Example: When the left Cylinder ignites first, the right one must ignite90°(Interval of 1 Cylinder) or 450°later (Interval of 5 Cylinders)
By Integration of the Conditions mentioned above there will remain72 Possibilities
16
Firing Orders V8, Cylinder Bank Angle 90°
Ignition 1 0° Ignition 2 90°
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 17
Firing Orders V8, Cylinder Bank Angle 90°
The preselected Firing Orders are processed by Use of DoE (GT) for one Operating Point and are evaluated on the Basis of followingCriteria:
Gas Exchange / Fuel Consumption
Free Forces and Torques
Torsional Oscillations of the Crankshaft
Maximum Bearing Wear
A Selection of Promising Firing Orders is additionally investigated at different Speeds on the Full-Load Curve
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 18
Results of a V8 Engine „Best“ Firing Order from GT-Suite DoE Investigation
10 N/mm²
Tor
sion
alSt
ress
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 19
Results of a V8 Engine„Best“ Firing Order from GT-Suite DoE Investigation
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 20
Results of a V8 Engine Comparison of Torsional Moments for Two Firing Orders
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 21
Results of a V8 Engine Calculated Cylinder Pressures at 1500 rpm
MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 22
Summary
GT-SUITE is capable of quantitatively correct Reproduction of theMain Effects concerning Crankshaft Stresses and Oscillations
GT-SUITE allows integrated calculations of crankshaft dynamicsand Gas Exchange/Engine Performance (GT-POWER)
Simultaneous Simulation of Gas Exchange Processes and mechanical Events offers more precise and reliable Results
Coupling Integrated Simulation with automated OptimizationProcedures in GT-SUITE yields better Results in a shorter Time, compared to separate Calculations