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Porsche Engineeringdriving technologies

Electrification of the powertrain.Further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

European GT-SUITE Conference, Frankfurt/Main, 21 October 2013

21.10.2013- 3 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

> Introduction

> Simulation procedure

> Concepts

> Simulation results

> Determination of power and energy demands

> Conclusions

Electrification of the powertrain – further potentials for downsizing?Contents

21.10.2013- 4 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

> Significant reduction of CO2 emissions for next generation vehicles.

> Vehicle performance limits the downsizing level.> Demand for a 48 V system and electrical

hybridization.> Electrification of the powertrain is a new degree

of freedom.

Optimization potential of synergic effects?

Introduction

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Potential of fuel consumption reduction

“Ideal Conditions”:ü Power inputû No inertiasû No additional weights

“Inertia Contribution”:ü Power inputü Polar inertiasû No additional weights

Preliminary design of the e-Machines

Battery sizing and total weights assumptions

“Real Conditions”:ü Power inputü Polar inertiasü Overall weights

Evaluation of Power and Energy

demands

Evaluation of Power and Energy

demands

Evaluation of Power and Energy

demands

Simulation Procedure> 3 levels of approximation for the investigation of hybrid concepts:

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

> Reference is a twin charged engine:

− Supercharger + turbocharger (SC+TC)

Other models are hybrid concepts with two different levels of hybridization.

> 3 thermodynamic hybridizations feasible with a system of 48 V:

− E-supercharger + turbocharger (eSC+TC)

− E-flowcharger + turbocharger (eFC+TC)

− E-turbocharger (eTC)

> 1 plug-in hybrid with a system of 280 V:

− turbocharger + e-cranktrain (TC+eCT);

Concepts

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Concepts – Reference SC+TC: Mechanical charger and turbocharger

> Turbo- and super-charged engine.

> SC works up to 3000 rpm (clutch).

> Bypass-valve for the SC.

> Additional CAC.

T

SC

1 CAC

2 CAC

C

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Concepts – Thermodynamic hybridizationeSC+TC: Electrically driven supercharger and turbocharger

T

SC

1 CAC

2 CAC

e-M

C

> Supercharger driven by an e-machine (no clutch).

> Boost pressure controlled by the e-Motor.

> E-Motor: 48 V SPM with external rotor.

− Peak power 8.0 kW

− Max. speed 7500 rpm

> Batteries: 13 lithium-polymer cells.

− Capacity 1.9 kWh

− Weight 11.7 kg

> +27 kg heavier than base model.

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Concepts – Thermodynamic hybridizationeFC+TC: Electrically driven radial compressor (flow charger) and turbocharger

* A DC/DC converter is needed

T

1 CAC

2 CAC

e-MFC

C

> Radial compressor driven by an e-machine.

> Boost pressure controlled by the e-Motor.

> E-Motor: 200 V* SPM.

− Peak power 9.0 kW;

− Max. speed 121 500 rpm;

> Batteries: 13 lithium-polymer cells.

− Capacity 1.9 kWh;

− Weight 11.7 kg;

> +23 kg heavier than base model.

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Concepts – Thermodynamic hybridizationeTC: Turbocharger assisted by electrical motor/generator mounted on turboshaft

Te-M

CAC

C

> Single stage turbocharger assisted by an e-machine.

> Only 1 CAC needed.

> Turbocharger is very close to surge limit.

> E-Motor: 200 V* SPM.

− Peak power 9.6 kW

− Max. speed 160 000 rpm

> Batteries: 13 lithium-polymer cells.

− Capacity 1.9 kWh

− Weight 11.7 kg

> +20 kg heavier than base model. * A DC/DC converter is needed

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Concepts – Plug-in hybridTC+eCT: Turbocharger plus an electrical motor/generator

TC

CAC

e-M/G

> Single stage turbocharger.

> Only 1 CAC needed for this configuration.

> Regenerative braking possible.

> E-Motor: 280 V SPM with concentrated windings.

− Peak power 57.6 kW

> Batteries: 76 lithium-polymer cells.

− Capacity 11.2 kWh

− Weight 68.4 kg

> +117 kg heavier than base model.

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

> Each engine is coupled with a model of a compact car.

> Four different acceleration maneuver have been analyzed:

− T1: from 60 to 100 km/h in 6th gear

− T2: from 80 to 120 km/h in 5th gear

− T3: from 80 to 120 km/h in 6th gear

− T4: from 100 to 200 km/h in 6th gear

> Simulation constrains for every concept:

− Consistent maximum torque

− Similar time per maneuver (if possible)

− Constant knock tendency (Knock Index)

− Maximum T3 of 950°C

Simulation Procedure

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Simulation Results

Enhanced torque build-up to compensate for the weight

disadvantage.

Maneuver T3 – Real Condition - 80 120 km/hr in 6th gear

21.10.2013- 14 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Simulation ResultsManeuver T3 – Real Condition - 80 120 km/hr in 6th gear

SC auxiliary torque

Turbolag compensation by e-cranktrain

21.10.2013- 15 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Simulation ResultsManeuver T3 – Real Condition - 80 120 km/hr in 6th gear

= ~ 6.5 – 7.5

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Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Determination of power and energy demandsProcedure

> Three main assumption are made for the electric energy recovering:

− Total electric recharge: energy is recovered by regenerative braking and / or charging.

− Partial electric recharge: energy is partially recovered while braking /charging, and partially by the internal combustion engine shifting the load operating point. *

− ICE recharge: energy demand is recovered by the combustion engine. **

* the energy demand is transformed in an equivalent of fuel with an overall efficiency of 30%

** transformation efficiency of 10%

21.10.2013- 17 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Partial electric recharge(η = 30 %)

Total electric recharge ICE recharge (η = 10 %)

21.10.2013- 18 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

***

***200/hr reached 0.7 seconds after the other models

Partial electric recharge(η = 30 %)

Total electric recharge ICE recharge (η = 10 %)

Partial electric recharge(η = 30 %)

Total electric recharge ICE recharge (η = 10 %)

Partial electric recharge(η = 30 %)

Total electric recharge ICE recharge (η = 10 %)

Partial electric recharge(η = 30 %)

Total electric recharge ICE recharge (η = 10 %)

21.10.2013- 19 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Conclusions

> Different level of hybridization have been evaluated:− Thermodynamic hybridization with a system of 48 V.

> Fuel consumption improvement up to 6 % with comparable transient behavior.

> Systems show a similar power demand.

− E-turbo: better packaging but limitations due to compressor surge and revolutions of the electrical machine

− E-flow charger: challenge to design a high revolution electrical machine (>150.000 rpm)

− Plug-in hybrid with a system of 280 V.> Improved thermodynamic engine efficiency during transient maneuvers.

> Significant higher vehicle weight.

> Fuel consumption reduction during transient maneuvers are heavily dependent on operating strategy (high degree of freedom) .

> Design of the powertrain is heavily dependent on the driving profile à “Diversification”− Full hybridization shows advantages in urban driving conditions.− Degree of electrification should be lower for driving profiles with long distances and constant speed.

> Hybridization of the powertrain leads to new requirements for the downsizing concepts. Higher total efficiencies are possible, but optimization needs to consider the driving profiles.

Porsche Engineeringdriving technologies

Thank you for your attention!

21.10.2013- 21 -

Electrification of the powertrain – further potentials for downsizing?V. Bevilacqua, E. Jacobs, G. Grauli, J. Wüst

Porsche Engineeringdriving technologies

Simulation ResultsManeuver T3 – Real Condition - 80 120 km/hr in 6th gear

Later enrichment due to turbolag