Attività di ricerca dell’Università di Genova sulle prestazioni dei … · 2018. 5. 7. ·...

1

Attività di ricerca dell’Università di Genova sulle

prestazioni dei componenti di aspirazione e

scarico di MCI automotive e sulle emissioni dei veicoli

stradali in condizione di reale utilizzazione

Massimo Capobianco, Silvia Marelli, Giorgio Zamboni

Internal Combustion Engines Group (ICEG)

Dipartimento di Ingegneria Meccanica, Energetica, Gestionale e dei Trasporti (DIME)

Università di Genova

Coordinamento Nazionale dei Professori

di Macchine a Fluido e Sistemi per l’Energia e l’Ambiente

Giornata di Studio sui Motori a Combustione Interna

Modena, 25 Maggio 2016

M. Capobianco, S. Marelli, G. Zamboni – Giornata di Studio sui MCI, Modena, 25.05.2016 2

Intake and Exhaust Components

Research Activity


Intake and Exhaust Components Research Activity

A dedicated test facility allows to study the behaviour of different automotive I/E components and subsystems both under steady and unsteady flow operation, with special reference to exhaust turbochargers

Experimental tests can be addressed to:

define the steady flow characteristics of I/E components in a wide operating range through suitable investigation techniques

investigate the behaviour of I/E components under pulsating flow conditions, highlighting the influence of the main flow parameters on components performance

study the transient response of I/E components and subsystems in order to optimize the relevant control strategies

Information provided by experimental research activity are used to define empirical correlations and to improve theoretical models within engine simulation codes (GT Power environment, …)


“Cold” (about 400 K) and “hot” (max 1000 K) air

tests on I/E components and subassemblies

Maximum available air flow rate 0.65 kg/s at 8 bar

Particularly suitable to test automotive

turbochargers: two independent feeding lines

available for the TC turbine and compressor

Electrical air heating modular system (max power

320 kW)

In the case of turbine investigations the

turbocharger compressor acts as a dynamometer

and proper experimental techniques are used to

extend the definition of turbine characteristics

Turbine and compressor performance can also be

investigated under unsteady flow by using two

different pulse generator systems:

Rotating valves pulse generator

Cylinder head pulse generator

I/E Components Test Facility

AF Air Filter LM Laminar Flow Meter AH Air Heater PC Pressure Control AR Air Reservoir PG Pulse Generator System APH Air Pre-Heater SC Screw Compressor C Compressor T Turbine LC Lubricating Circuit TM Thermal Mass Flow Meter


Turbocharger

Compressor air supply

Flow distributor

Turbine air supply

TurbochargerT C

Rotating valves

Compressor air supply

Turbine air supplya)Plenum

Manifold

Engine head

T C

Plenum

b)

Designed to perform parametric studies

(effect of unsteady flow parameters on

component performance)

Tests on single and two-entry devices

allowed

Pulsating flow generated by diametral

slot rotating valves

Easy control of pressure pulse

parameters (amplitude, mean value) at

each device entry by controlling the

upstream plenum pressure and by

properly mixing a steady and a

pulsating flow component

Pulse frequency can be adjusted in the

typical range of automotive I/E circuits

(10-200 Hz)

Unequal admission and not-phased

pulsating flow conditions can be

reproduced when testing two-entry

devices

Rotating Valves Pulse Generator System


CT Turbocharger

Plenum

Flow distributorEngine head

Manifold Compressor air supply

Turbine air supply

Designed to investigate engine intake and exhaust subsystem behaviour under unsteady flow conditions, including the effect of:

circuit geometry

valve actuation strategies

The system is based on a motor-driven cylinder head connected to a device designed to reproduce the engine cylinder block

The cylinder head can be fitted with a fully flexible VVA system

Cylinder Head Pulse Generator System

Application to the turbine circuit

Application to the compressor circuit

7 M. Capobianco, S. Marelli, G. Zamboni – Giornata di Studio sui MCI, Modena, 25.05.2016

Experimental definition of TC maps

Measurement of turbocharger steady flow maps over an extended range to improve simulation models results

Experimental techniques to extend turbocharger steady flow curves

Turbine performance defined considering the effect of waste-gate valve or VGT

Turbine efficiency decreases when the waste-gate valve is open (if isentropic power is referred to the total mass flowing through the system)


Turbine unsteady performance

At typical pulsating flow frequencies occurring in the exhaust system of automotive engines the pulse is so rapid that mass flow does not have enough time to incrementally fill the volute volume with pressure hysteresis loop

Deviation of unsteady efficiency from the steady state values

Loop area variation by changing pulse frequency and waste-gate valve opening

0.0

0.2

0.4

0.6

0.8

1.0

Tota

l-to-

stat

ic e

ffic

ienc

y

αWG = 0100 HzSteady state

0.00.20.40.60.81.0

Tota

l-to-

stat

ic e

ffic

ienc

y

αWG = 8

0.00.20.40.60.81.0

Tota

l-to-

stat

ic e

ffic

ienc

y

αWG = 20

0.0

0.2

0.4

0.6

0.8

1.0

0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

Tota

l-to-

stat

ic e

ffic

ienc

y

Blade speed ratio

nt/√TT3 = 6000 rpm/√KpS3mean = 1.8 bar

αWG = 63


1.0

1.1

1.2

1.3

1.4

1.5

1.6

0.00 0.02 0.04 0.06 0.08 0.10

Pre

ssu

re

ra

tio

to

tal-

to-to

tal

Corrected mass flowrate [kg/s]

Strategy A - unsteady average levels

Strategy B - unsteady average levels

Strategy C - unsteady average levels

Steady state

Strategy A - instantaneous levels

Strategy B - instantaneous levels

Strategy C - instantaneous levels

100000 rpm

80000 rpm

120000 rpm

140000 rpm

a

1.0

1.1

1.2

1.3

1.4

1.5

1.6

0.00 0.02 0.04 0.06 0.08 0.10

Pre

ssu

re

ra

tio

to

tal-

to-to

tal

Corrected mass flowrate [kg/s]

100000 rpm

80000 rpm

120000 rpm

140000 rpm

b

2-cylinder configuration

Significant deviation from steady state resulting in a hysteresis loop surrounding the steady state

Surge line shifting towards lower mass flow rate levels

Compressor stable zone enlarged under heavier unsteady flow conditions

Compressor unsteady performance


Heat transfer effects

At low nTC, compressor is strongly affected by heat transfer from turbine and oil casing compressor outlet temperature (TT2) results overestimated

Significant impact of heat transfer on both compressor and turbine (termo-mechanical) efficiency

Development of a specific model to correct TC maps for heat transfer

sttot

cTCm

sttot

tTCmTStt

TT

TsTc

hM

P

hM

P

TT

TT

'

12

12


Characteristic curves extension

Improvement of variable geometry and waste-gate turbine modelling

Extrapolation of compressor curves on the left side of the surge line

Modelling activities in GT-Power

Specific studies on turbocharging systems aimed at deepening and improving GT-Power interpolation and extrapolation procedure of turbocharger performance maps and engine-turbocharger matching


Characteristic curves extension

Improvement of variable geometry and waste-gate turbine modelling

Extrapolation of compressor curves on the left side of the surge line

Modelling activities in GT-Power

Specific studies on turbocharging systems aimed at deepening and improving GT-Power interpolation and extrapolation procedure of turbocharger performance maps and engine-turbocharger matching

Experimental data

Modelled data


Investigation topics for efficient engine turbocharging

• Correlation between hot and cold turbine maps • Direct measurement of turbine isentropic efficiency • Heat transfer phenomena within the turbocharger (air-oil-water-exhaust gases) • Evaluation of turbocharger mechanical losses • Optimization of TC regulating device control (waste-gate, VGT) under unsteady flow

conditions

• Effect of unsteady flow and transient operation on compressor and turbine performance

• Compressor surge detection and active control • Interactions between EGR and turbocharging circuits • Effect of aftertreatement device position on turbocharger performance • E-boosting systems • Subassembly characterization (TC + engine I/E circuit) • …..

Improvement of turbocharger simulation models within commercial codes (GT Power, etc)


Some ICEG References on I/E Components

M. Capobianco, A. Gambarotta, "Unsteady flow performance of turbocharger radial turbine", 4th International Conference on Turbocharging and Turbochargers, 1990.

M. Capobianco, A. Gambarotta, "Variable geometry and waste-gated automotive turbochargers: measurements and comparison of turbine performance", ASME Transactions, Journal of Engineering for Gas Turbine and Power, 1992.

M. Capobianco, A. Gambarotta, “Performance of a twin-entry automotive turbocharger turbine”, ASME Energy-Sources Technology Conference and Exhibition, 1993.

M. Capobianco, S. Marelli, “Turbocharger turbine performance under steady and unsteady flow: test bed analysis and correlation criteria”, 8th International Conference on Turbochargers and Turbocharging, 2006.

M. Capobianco, S. Marelli, “Waste-gate turbocharging control in automotive SI engines: effect on steady and unsteady turbine performance”, SAE paper 2007-01-3543, 2007.

F. Piscaglia, A. Onorati, S. Marelli, M. Capobianco “Unsteady Behavior In Turbocharger Turbines: Experimental Analysis And Numerical Simulation”, SAE Paper 2007-24-0081, 2007.

S. Marelli, M. Capobianco, “Steady and pulsating flow efficiency of a waste-gated turbocharger radial flow turbine for automotive application”, Energy 36, pages 459-465, doi: 10.1016/j.energy.2010.10.019, 2011.

F. Bozza, V. De Bellis, S. Marelli, M. Capobianco, “1D Simulation and Experimental Analysis of a Turbocharger Compressor for Automotive Engines under Unsteady Flow Conditions”, SAE Paper 2011-01-1147, 2014.

S. Marelli, M. Capobianco, G. Zamboni, “Pulsating Flow Performance of a Turbocharger Compressor for Automotive Application”, Int. J. of Heat and Fluid Flow 45, pages 158-165, doi: 10.1016/j.ijheatfluidflow.2013.11.001, 2014.

S. Marelli, C. Carraro, G. Marmorato, G. Zamboni, M. Capobianco , “Experimental Analysis on Steady Flow Performance under Unstable Operating Conditions and on Surge Limit of a Turbocharger Compressor”, Experimental Thermal and Fluid Science 53, pages 154-160, doi: 10.1016/j.expthermflusci.2013.11.025, 2014.

S. Marelli, G.Marmorato, M. Capobianco, A. Rinaldi, Heat transfer effects on performance map of a turbocharger compressor for automotive application, SAE Technical paper no. 2015-01-1287, 2015.

S. Marelli, S. Gandolfi, M. Capobianco, Experimental and Numerical Analysis of Mechanical Friction Losses in Automotive Turbochargers, SAE Technical paper no. 2016-01-1026, 2016.


Assessment of road vehicles

environmental impact

in real-world conditions


Road vehicles emissions in real-world conditions

The main investigations developed in this field are focused on:

• Definition of hot and cold exhaust emission factors for pollutants (CO, HC, NOX, NO2, CO2 and PM) referred to different vehicle categories (passenger cars, light and heavy

duty vehicles, buses, motorcycles, mopeds, waste collection vehicles)

• Development of experimental and/or statistical methodologies for the assessment of the real circulating fleet and mileage and the definition of typical trips with the relevant

driving characteristics

• Development and application of a dedicated theoretical model (PROGRESS code) to predict the environmental impact of road vehicles in urban areas

Next step:

• Vehicles modeling in GT-Suite environment to compare emissive and energy behavior on different driving cycles


Motorcycles and mopeds behavior in cold start and hot conditions (in co-operation with Istituto Motori-CNR)

• Analysis of the influence of driving cycles and real world speed patterns on hot and cold emission factors

• Effects of engine and catalyst operation on exhaust emissions in the cold transient phase

Genoa experimental speed patterns Measured levels of speed above UDC and

comparable to WMTC

RPA levels (that is, cycle dynamics) significantly

higher in real conditions


CO cumulative emissions, relative air/fuel ratio and catalyst temperature during a real world driving cycle

Cold contribution as percentage of the

total emission and fuel consumption on

different driving cycles – Euro 2 moped

225 s

115 s

Hot phase linear regression

y = 0,0348x + 16,598

R2 = 0,9989

0

15

30

45

60

75

90

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Time [s]

CO

cu

mu

lati

ve

em

iss

ion

[g

]

CO total emission

Hot phase extrapolation

Hot phase linear regression

Cold

transient Scooter A - IRC

225 s115 s

0,7

0,8

0,9

1

1,1

1,2

1,3

1,4

1,5

0 50 100 150 200 250 300 350 400 450 500

Time [s]

Rela

tiv

e a

ir/f

uel

rati

o

0

100

200

300

400

500

600

700

800

Cata

lys

t in

let

tem

pera

ture

[°C

]

Scooter A - IRC

l

t cat in

Driving cycle/speed pattern

CO HC NOx Fuel

consumption

ECE 47 68.8 72.9 - 6.5 IUFC (real world) 32.3 53.5 27.8 6.9 24-slow (Genoa speed pattern) 39.5 52.3 26.2 9.3 3-slow (Genoa speed pattern) 35.6 48.4 6.9 7.6

Motorcycles and mopeds behavior in cold start and hot conditions (in co-operation with Istituto Motori-CNR)


HDV Activities in Genoa Port Area (in co-operation with Lab. Transports et Environnement – IFSTTAR)

Definition of HDV daily flows

through highway exits and share of

vehicles entering port terminals

Classification of vehicles involved in

port activities referring to type,

mass range and number of axles

44,9%42,6% 44,0% 42,0%

57,2% 57,8%

83,4%

79,0%75,6%

72,2%

94,6% 95,6%

40%

50%

60%

70%

80%

90%

100%

0

1000

2000

3000

4000

5000

6000

2002 2005 2008 2010 2014 2015

Num

ber o

f veh

icle

s/da

y (c

lass

es 3

, 4 a

nd 5

)

Total (Exits 1 - 7) Exits 1 and 4 Vehicles with O-D = portPort / Exits 1-7 Port / Exits 1 and 4

0

5

10

15

20

25

30

35

40

RT 1 RT 2 RT 3 TT/AT 1 TT/AT 2 TT/AT 3 TT/AT 4 TT/AT 5

Vehi

cle

shar

e in

por

t are

a [%

]

Rigid truck (RT)- RT 1 = 2 axles, < 14 t- RT 2 = 3-4 axles, 14 28 t - RT 3 = 4-5 axles, > 28 t

Truck trailer (TT)Articulated truck (AT)- TT/AT 1 = 3 axles, > 14 20 t- TT/AT 2 = 3-4 axles, > 20 28 t- TT/AT 3 = 4-5 axles, > 28 34 t- TT/AT 4 = 5 axles, > 34 40 t- TT/AT 5 = 5 axles, > 40 t


Acquisition and processing of instantaneous

speed related to the typical trips in urban zones

(highway exit – port gates) and within the port

area

Application of PHEM to the experimental speed

profiles to estimate fuel consumption and

emission factors for selected HDV classes

0

5

10

15

20

25

30

35

40

45

0 1000 2000 3000 4000 5000

Spe

ed [k

m/h

]

Time [s]

GI

P1

P2 LM1 T1 LM2 P3

P4

GO(a)

Average speed in port area = 4.4 km/h, idling

time = 74%, travelled distance = 6.6 km

0

10

20

30

40

50

Euro 3 Euro 5SCR

Euro 5EGR

Euro 3 Euro 5SCR

Euro 5EGR

Euro 3 Euro 5SCR

Euro 5EGR

NO

Xem

issi

on fa

ctor

[g/k

m]

GT1 GT3 Urban driving mode

Truck trailer/Articulated track 14 20 t

Truck trailer/Articulated track 28.1 34 t

Truck trailer/Articulated track > 40 t

HDV Activities in Genoa Port Area (in co-operation with Lab. Transports et Environnement – IFSTTAR)


Recent papers from ICEG on road vehicle emissions

G. Zamboni, M. Capobianco, E. Daminelli, Estimation of road vehicle exhaust emissions from 1992 to 2010 and comparison with air quality measurements in Genoa, Italy. Atmospheric Environment 43, pages 1086-1092, 2009, doi:10.1016/j.atmosenv.2008.11.014.

G. Zamboni, C. Carraro, M. Capobianco, On-road instantaneous speed measurements on powered two-wheelers for exhaust emissions and fuel consumption evaluation. Energy 36, pages 1039-1047, 2011, doi: 10.1016/j.energy.2010.12.004.

M.V. Prati, G. Zamboni, M.A. Costagliola, G. Meccariello, C. Carraro, M. Capobianco, Influence of driving cycles on Euro 3 scooter emissions and fuel consumption. Energy Conversion and Management, 52, pages 3327-3336, 2011, doi: 10.1016/j.enconman.2011.06.004.

G. Zamboni, M.V. Prati, C. Carraro, S. Malfettani, M.A. Costagliola, G. Meccariello, S. Marelli, M. Capobianco, Influence of Driving Cycles on Powered Two-Wheelers Emissions, Fuel Consumption and Cold Start Behavior. SAE Technical Paper 2013-01-1048, doi:10.4271/2013-01-1048.

G. Zamboni, S. Malfettani, M. André, C. Carraro, S. Marelli, M. Capobianco, Assessment of heavy-duty vehicle activities, fuel consumption and exhaust emissions in port areas. Applied Energy, vol. 111, pp. 921-929, 2013, doi: 10.1016/j.apenergy.2013.06.037.

G. Zamboni, M. André, A. Roveda, M. Capobianco, Experimental evaluation of Heavy Duty Vehicle speed patterns in urban and port areas and estimation of their fuel consumption and exhaust emissions. Transportation Research Part D: Transport and Environment, vol.35, pp.1-10, 2015, doi: 10.1016/j.trd.2014.11.024.

G. Zamboni, M. André, Evaluation of emissions and fuel consumption of Heavy-Duty Vehicles in urban areas, 21st Transport and Air Pollution Conference, Lyon, 24-26 May 2016.


Thank you for the attention!

Contacts

Massimo Capobianco phone +39.010.353.2446 mobile +39.328.1004793 e-mail [email protected]

Silvia Marelli phone +39.010.353.2443 mobile +39.335.8726110 e-mail [email protected]

Giorgio Zamboni phone +39.010.353.2457 mobile +39.320.4320003 e-mail [email protected]

Università di Genova – DIME Via Montallegro 1 - 16145 Genova – Italy

www.iceg.unige.it

Attività di ricerca dell’Università di Genova sulle prestazioni dei … · 2018. 5. 7. ·...

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