Firing Order Optimization Based on Integrated Simulation · PDF fileMAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 1 Firing Order Optimization

MAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 1

Firing Order Optimization Based on Integrated Simulation

Jürgen KnorrThomas MalischewskiJoachim Weiß


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 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


Motivation: Irregular Cylinder Pressures(V8 Gas-Engine)


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 %


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


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


Example ModelD2868 Yacht Engine

Complete Air Path with Compressors and Coolers

Detailed Combustion Model

Exhaust Piping with Turbines

Crankshaft

Damper

Flywheel

BrakeCardan Shaft


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


Torsional TorquesTest Equipment of a V12 Engine


Torsional TorqueRun-Up of a V12 Engine, Experimental Results

Engine Speed

Signal (Torque)


Torsional TorquesRun-Up of a V12 Engine


Crankshaft Twisting Angle6-Cylinder In-Line-Engine


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°


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


Results of a V8 Engine „Best“ Firing Order from GT-Suite DoE Investigation

10 N/mm²

Tor

sion

alSt

ress


Results of a V8 Engine„Best“ Firing Order from GT-Suite DoE Investigation


Results of a V8 Engine Comparison of Torsional Moments for Two Firing Orders


Results of a V8 Engine Calculated Cylinder Pressures at 1500 rpm


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

Documents

Firing Order Optimization Based on Integrated Simulation · PDF fileMAN Nutzfahrzeuge AG Knorr, Malischewski, Weiß Firing Order Optimization October 25, 2010 1 Firing Order Optimization