simulation of a pre-compressor swirl device using gt-suite · 16/10/17 simulation of a...
TRANSCRIPT
16/10/17
Simulation of a pre-compressorswirl device using GT-SUITE
Anita Bongards, Dr. Wolfgang Wenzel, Jerry Song
© BorgWarner Inc. 2
pre-compressor swirl device
a.k.a. Inlet Swirl Throttle = IST
Before we start …
© BorgWarner Inc. 3
� Background and Motivation
� Hardware Description and Setup
� Project Layout
� Modeling Process: Necessary Input, Calibration, Challenges
� Effects on Engine at Full Load
� Summary and Outlook
Content
© BorgWarner Inc. 4
� New emission legislation (WLTC, RDE) requires a combination of engine internal measures and aftertreatment for NOx emission reduction.
� External EGR is used in the complete engine map.
� Low pressure EGR systems are fully established.
� Single stage TC applications move to higher torque/power.
Air System Trends – Boosting Needs
Diesel Engines
AVL
© BorgWarner Inc. 5
Inlet Swirl Throttle
LP-EGR Valve
Inlet Swirl Throttle
Air
Exh
. gas
Intake/ Exhaust Throttle
Inlet Guide Vanes
Turbocharger
Throttling (Diesel)
Improved LP-EGR mixing
Improved compressor performance� Efficiency� Surge behavior
© BorgWarner Inc. 6
Close to surge line Compressor design area Close to choke line
Pre-swirl reduces incidence angle and increases compressor speed
Negative pre-swirl increases incidence angle and reduces turbo speed
Incidence angle is ideal, no pre-swirl required
Inlet Guide Vanes – Influence on Aerodynamics
© BorgWarner Inc. 7
Design� Optimized flow� Modular� compact
EngineDyno testing
Hot gas bench testing� Several generations of
prototypes� Varying levels of detail
Controls development� Based on BorgWarner Air
Systems Controller� Developed in Simulink� Actuated: VTG, EGR-
valves, IST� Linked to GT for testing
GT-POWER simulation� Support test and controls
engineers� Enable further
investigations after dynotesting was finished
� Closely linked to other sub-projects
Project Layout
© BorgWarner Inc. 8
Modeling – Setup 1 & 2
Engine data
� 2.0 L Diesel engine� 105 kW rated Power� EPA Tier 2 Bin 5 � HP & cooled LP-EGR
LP-EGR setups
1. LP-EGR-valve, exhaust throttle, conical pipesection on intake side
2. LP-EGR-valve, IST, pipe section replacingexhaust throttle
Setup 2: IST
Setup 1: Exhaust throttle
© BorgWarner Inc. 9
Modeling – Detailed to Fast Running Model
72 flowvolumes
268 flowvolumes
� Simplifying model� Combining subvolumes� Re-Adjusting pressure losses
=> FRM 3-4 times faster thandetailed model
© BorgWarner Inc. 10
0 deg
35 deg
50 deg
75 deg
Modeling – Functions of the IST and Input
Function:
� Throttling
� Efficiency
� Surge line
� (Improved mixing)
Flow bench data
Hot gas stand data
Benefits can not besimulated currently
© BorgWarner Inc. 11
0 deg
35 deg
50 deg
75 deg
Modeling – Functions of the IST and Input
Function:
� Throttling
� Efficiency
� Surge line
� (Improved mixing)
GT-lookupFlow bench data
GT-cmpHot gas stand data
Benefits can not besimulated currently
© BorgWarner Inc. 12
Challenges with 1st IST Measurements
Measurement on Hot gas stand across wholeassembly
compressor
IST
LP-EGR
p21, T21
p12, T12
p11, T11
In the first measurementcampaign only 4 IST positionsmeasured
Changes between angles are not linear
35 deg 50 deg 75 deg
Solution: 7 different positions measuredDelta IST smaller for higher angles
Not possible to model compressorbehaviour if LP-EGR is applied!
Solution: Additional temperature &pressuresensors between IST & cmp
© BorgWarner Inc. 13
Full load data comparison
Dyno data
Simulation
Cone Inlet
ISTIncreased LET
Increased n-Turb
Decreased n-Turb
Increased efficiency
Positive IST-angles increasecompressor efficiency andturbocharger speed
Negative IST-angles decreaseturbocharger speed and canhelp with altitude reserves
Correlation FRM-Model to Dyno Data
© BorgWarner Inc. 14
Compressor maps at 1375rpm
Compressor is operating at different massflow and pressure conditions
At same pressure ratio operation without IST would lead to surge behaviour, andworse efficiency
Compressor Behaviour
© BorgWarner Inc. 15
� IST modelling completed with throttling & efficiency feature
� IST combines EGR enhancement function with efficiency benefits and
improves surge behaviour
� Lessons learned:
� additional measuring points at Hot gas bench testing necessary
� at least 7 IST positions necessary for acceptable simulation accuracy
� Still neglecting effects of better mixing and turbine performance
� Product development going on, samples available and being evaluated
by customers
Summary and Outlook
© BorgWarner Inc. 16
Thank you!