Integrated 1D Simulation - Gamma Technologies · 2016-07-01 · fuel injector. and . exhaust valve drive . for a large, low-speed 2-stroke marine engine application . Engine Characteristics

Filip Cernik, CTU Prague

Integrated 1D Simulation for a Large Low-Speed 2-Stroke Marine Engine

2

Injector Model

OUTLINE

Combustion Routine

Exhaust Valve Drive Model

Integrated Simulation

Summary

Introduction

© WinGD, 26-Oct-2015 - GT User’s Conference Frankfurt / Integrated 1D Simulation

Introduction

Injector Model

Combustion Routine



Summary

3 © WinGD, 26-Oct-2015 - GT User’s Conference Frankfurt / Integrated 1D Simulation

Motivation

Develop an integrated standalone model including the engine, fuel injector and exhaust valve drive for a large, low-speed 2-stroke marine engine application

Engine Characteristics

Large low-speed 2-stroke uniflow-scavenged turbocharged diesel or DF engine

Variable exhaust valve with hydraulic actuation

Common rail injection system for both MDO/HFO

Fuel Actuated Sacless Injectors (FAST)

ICC for optimum engine performance

Both Diesel & DF versions IMO Tier3 compliant

INTRODUCTION


Engine Power [kW] 21‘660

Number of cylinders 6

Bore [mm] 720

Stroke [mm] 3086

Engine speed [rpm] 84.0

Piston speed [m/s] 8.6

Compression Ratio [-] 18.8

Boost pressure, ISO [barg] 3.6

Fuel rail pressure [bar] 950

Number of injectors per cylinder 3

dimensions in [m]

W6X

72 E

ngin

e Sp

ecifi

catio

n (C

MC

R) INTRODUCTION


EXHAUST VALVE ENGINE INJECTOR

EV lift profile

p-cyl p-exh

p-servo EVO/EVC

injection rate

p-cyl p-rail

IT load

user combustion model

caburn00a, dwi1,dmascomb

INTRODUCTION


Injector Model

Introduction

Combustion Routine



Summary

© WinGD, 26-Oct-2015 - GT User’s Conference Frankfurt / Integrated 1D Simulation 7

Flow Fuse


INJECTOR MODEL

p_Inj1_2

Control Valve

Inj Valve Spring

Needle

InjNozzConn

Nee

dle

Lift

Inj V

eloc

ity

Mas

s Fl

ow

Pre

ssur

e D

rop

INJECTOR MODEL

Simulation at 100,75,50,25% load at constant p-rail

Very good match for injection pressure at all load points

Pressure drop at SOI & oscillation frequency after EOI well captured

Lower pulsation peaks since only single injector simulated (3 injectors measured)

Unfortunately, no needle lift measurements available for further validation


measured data in blue!

Pres

sure

(100

%)

Pres

sure

(50%

)

Pres

sure

(75%

) Pr

essu

re (2

5%)

Combustion Routine

Introduction

Injector Model



Summary


-2.0°CA SOI 2.8°CA 4.6 °CA 6.4°CA 8.2 °CA 10.4 °CA 13.6°CA 17.2°CA 20.0°CA

EOI

COMBUSTION ROUTINE

20.3bar MEP, 950bar, 1/230x real time

Time scale combustion model

Simplified TKE solution validated against CFD

Spray penetration/angle correlation derived from experimental investigations in SCC

Burn rate dependency on injection rate profile & spray interactions

Implementation into GT-Suite by means of user routine

𝑑𝑑𝑓,𝑏,𝑑𝑑𝑓𝑓

𝑑𝑑= 𝐶

1𝜏𝑑𝑑𝑓𝑓

𝑑𝑓,𝑢𝑢



Introduction

Injector Model

Combustion Routine


Summary


p_VCUaftRod2

p_VCUin2

p_AirSp2

p_EVin2

p_EVDamp2 (no signal)

p_EV1Pist2

Spool lift

EV lift

VALV

E C

ON

TRO

L U

NIT

(VC

U)

HYD

RAU

LIC EX

HAU

ST VALVE DR

IVE

Detailed hydraulic exhaust valve drive model

Calibration & validation done against measurements

gas force

EXHAUST VALVE DRIVE


EXHAUST VALVE DRIVE


Simulation results compared against measured signals for hydraulic circuit as well as for air spring pressure and EV lift

Good level of model predictivity

Fine tuning of restrictive parts (orifice, subvolume) in order to maximize ∆t

Optimum between run time and model sensitivity has been found

EXHAUST VALVE DRIVE

p-servo oil variation engine load sweep


EV lift simulation in agreement with measurements over the entire engine load range

Correct response on servo-oil pressure variations reflected in the opening velocity response

Valv

e Li

ft

Valv

e Li

ft


Introduction

Injector Model

Combustion Routine


Summary


Integrated simulation performed for a typical 2-s marine engine load sweep on the propeller curve

Results validated against experimental engine data

Cylinder pressure traces fit well the test data for both compression and firing peaks

INTEGRATED SIMULATION


In order to minimize the CPU time following measures were applied: Reduction of the detailed engine into a single cylinder engine (SCE) model

GT circuit solution - each flow and mechanical circuit takes its own ∆t

Flow circuits: engine, EV and injector

ODE (mechanical) circuits: crankshaft, EV mechanics (implicit integrator), Injector mechanics

Sensitivity study on components that limit ∆t the most, such as small volumes/pipes

Cycle skipping of hydro-mechanical circuits

‘InjNozzConn’ (injector nozzle holes) allows injector calculation to shutoff, saving CPU time

EV flow circuit linked to the injector circuit by zero-orifice to enable EV cycle skipping


INTEGRATED SIMULATION

CPU time for 100% load case

Detailed engine model basis 63 min SCE model w/ inj skip 23 min SCE model w/inj skip optimized 11 min Use skip improvements in v2016 3 min


INTEGRATED SIMULATION zoom-in all circuits

∆t constrained mainly for the injector flow circuit

EV hydraulics present limitation especially during the scavenging period

Engine flow & mechanics allow large ∆t

Summary

Introduction

Injector Model

Combustion Routine




SUMMARY

Integrated simulation model for a large diesel 2-stroke marine engine derived & validated

Individual models as well as the integrated runs in good agreement with measurements

Model reduction and optimization reduces CPU time considerably

Integrated simulation eliminates multiple SW license costs and omits time consuming iterations for individual engine components

Present approach enhances system level analysis and accelerates development process

Potential for further run time reduction (v2016, Injection Rate Map)


Shawn Harnish Gamma Technologies

prof. Jan Macek CTU Prague

Sebastian Hensel Christoph Dahnz Yongfeng Jia winGD

ACKNOWLEDGMENTS


23

Thank you for your attention!

Documents

Integrated 1D Simulation - Gamma Technologies · 2016-07-01 · fuel injector. and . exhaust valve drive . for a large, low-speed 2-stroke marine engine application . Engine Characteristics