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Alessandro Renna
Daniel Baumann, IT
AVL Powertrain UK Ltd.
Confidential
RAPID ASSESSMENT OF ELECTRIC SUPERCHARGER
SYSTEM LAYOUTS FOR ENGINE DOWNSIZING
Electronics & Controls Department
28th/29th October 2015
National Motorcycle Museum, Solihull
Alessandro Renna | | 26 October 2015 | 2 Confidential
AGENDA
1. Engine downsizing
2. Simulink MVEM
3. Steady – State validation
4. EDS effect i. Steady – State
ii. Transient Response
iii. Vehicle Response
5. Conclusions
Alessandro Renna | | 26 October 2015 | 3 Confidential
ENGINE DOWNSIZING
• Engine downsizing to reduce fuel consumption and CO2 emissions
• Superchargers and turbochargers can recover BMEP reduction
• Turbochargers have slow transient response (turbo lag) and compressor surge limits air mass filling and torque at low speeds
• Electric driven superchargers (EDS) can provide good boosting particularly at low engine speeds without taking power from the engine (mechanical supercharger solution)
Alessandro Renna | | 26 October 2015 | 7 Confidential
SIMULINK MVEM: ADIABATIC PIPE
Rm
pVT
WWdt
dm
HHVc
R
dt
dp
p
21
21
Alessandro Renna | | 26 October 2015 | 9 Confidential
SIMULINK MVEM: SHAFT, AIR COOLER
)( ambininout TTeffTT dt
dJbTQTQ outin
Alessandro Renna | | 26 October 2015 | 11 Confidential
STEADY – STATE VALIDATION (ONLY TURBOCHARGER)
• Based on real WOT performance for a 1.0L engine with one turbocharger and one after-cooler.
• Reference pressure for waste-gate controller has been set equal to experimental values.
Alessandro Renna | | 26 October 2015 | 12 Confidential
EDS LAYOUTS
Based on validated TC model (only turbocharger), several combinations of turbocharger, electric supercharger and additional inter-cooler have been investigated.
Alessandro Renna | | 26 October 2015 | 13 Confidential
STEADY – STATE: COMPARISON
• Full load simulations with predefined PR set-points.
1
1
PRTWcP inp
Alessandro Renna | | 26 October 2015 | 14 Confidential
STEADY – STATE: COMPARISON + IC
• Full load simulations with additional inter-cooler and the same predefined PR set-points.
1
1
PRTWcP inp
Alessandro Renna | | 26 October 2015 | 15 Confidential
STEADY – STATE: COMPARISON
IC
IC IC
IC
refin
refin
corrpp
TTWW
/
/
Alessandro Renna | | 26 October 2015 | 16 Confidential
TRANSIENT RESPONSE
Transient response at fixed engine speed of ETC, TEC, ECTC and TCEC versus only TC model has been simulated using 2 step signals:
• Throttle tip-in to 100%;
• Electric motor torque for EDS from 0 to 1 Nm;
• Motor is disconnected for EDS PR set-points equal to 1.
EDS and turbocharger inertias are set equal to 5E-05 kg*m2.
Alessandro Renna | | 26 October 2015 | 19 Confidential
VEHICLE RESPONSE
dt
dvMFFFF v
vgraderollairt
sin
cos
2
1 2
gMR
gMCR
vACR
vgrade
vrroll
vfrontaldairair
iTQR
F
ivR
n
eng
w
fric
t
veng
2
60
ηfric i Rw Mv Afrontal ρair Cd Cr ϑ
0.8 4 0.3 [m] 1200 [kg] 2 [m2] 1.2 [kg/m3] 0.4 0.015 0 [deg]
Alessandro Renna | | 26 October 2015 | 22 Confidential
CONCLUSIONS - 1
Steady – State simulations showed:
• EDS can completely recovers the WOT torque deficit at low speeds and its position is not relevant to reach the nominal engine torque
• EDS in 2nd stage can extend the range of use from 1700 rpm to 3200 rpm but with increase of electric power request
• EDS wheel in TEC is more stressed at higher temperatures, so it needs better thermal characteristics and hence more expensive
IC
IC
IC
Alessandro Renna | | 26 October 2015 | 23 Confidential
CONCLUSIONS - 2
Transient simulations showed:
• Transient reduction of turbo lag during acceleration
• ETC and TEC models have basically the same trend
• Vehicle dynamic during tip-in manoeuvre improved without any significant influence of the EDS position
IC
IC
IC
Alessandro Renna | | 26 October 2015 | 24 Confidential
CONCLUSIONS - 3
Use of additional air cooler between the compressors showed:
• Extra increase of WOT torque with the same boost conditions
• Reduction of second stage temperatures
• No improvement of acceleration lag; it just moves operating points of the first stage compressor far from surge.
• Weight, volume and costs of the engine increase
IC
IC
IC
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