R E N A U LT N I S S A N T E C H N O L O G Y &B U S I N E S S C E N T R E I N D I A P R I VAT E L I M I T E D

Uprating of Naturally Aspirated Gasoline Engine Using Hybrid

Turbocharging SystemRangarajan S , Sundar S M , Venkata Rao G,

Alain Lefebvre, Anand Gurupatham

India GT Conference 2019 Jan 21, 2019

Powertrain CAE - Systems

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Contents

01 I n t r o d u c t i o n

02 Tu r b o c h a r g e r M o d e l i n g

03 E-charger Modelling

04 S i m u l a t i o n R e s u l t s

05 C o n c l u s i o n

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Introduction

A) Objective

B) Target

- To enhance the engine performance by using Hybrid

Turbocharger - coupling of electric supercharger and

mechanical turbocharger with naturally aspirated

(NA) engine.

- Low end torque (LET), drivability and bsfc are

improved by making use of best operating range of

both turbo and e-supercharger.

C) Engine specification

- 1.2L gasoline engine model is considered for our study

(base model).

- The base model is validated with test data.

- Deviation:

Test Vs Simulation: +/-5%

1.2L NA Engine Parameters:

Displacement Volume 1.2L

Bore 78 mm

Stroke 83.6 mm

Compression Ratio 12

Rated Power 57kW @ 5600rpm

Maximum Torque 102 Nm @ 3600rpm

EGR No

VVT Only Intake side

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Turbocharger Modelling

A) Methodology

NA Engine

• Baseline NA-engine model calibrated for Steady and Transient run.

• Deviation is +/-5% with test data.

• This model is considered as base model for all simulations carried out for this work.

TC Engine

• Selection of Conventional Turbocharger (TC-Matching) for Steady state operation.

• Validation of Conventional Turbocharger (TC-Matching) for Transient operation ( Turbo lag study).

• Results comparison.

E-charger

Engine

• Selection of e-charger compressor map.

• Selection of Battery, Motor and/or Generator specification.

• E-charger control logic.

• Coupling of Turbocharger and e-Charger (TC & e-Charger Matching) for Transient operation using NEDC cycle.

• Results comparison.

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E-charger selectionB) Map Selection using DOE

Turbocharger Modelling

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C) Layout – Engine + TC + e-charger

Turbocharger Modelling

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D) E-charger Control logic

- Operation of e-charger depends mainly on - engine speed and battery SOC.

- SOC is limited between 0.9 and 0.6.

- Discharging and charging of battery is at engine speeds 1000 to 1650 rpm and 2700 to 5600 rpm respectively.

Motor/Generator output 0.5 kW

Motor maximum current 180 A

Motor maximum speed (with Gear ratio) 150000 rpm

Battery 12V DC

Battery capacity 50A-h

Battery, Motor and/or Generator Specification:

E-charger Modelling

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A) Steady state results at WOT

• Engine Torque

˗ Overall torque Improvement is 92% at 1600 rpm.

Simulation Results

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Simulation Results

A) Steady state results at WOT

˗ At 1600rpm, overall volumetric efficiency improvement is 79% for NA engine to system-2

• Engine Volumetric efficiency

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Simulation Results

A) Steady state results at WOT

˗ The maximum BSFC improvement is 6.64% at 1600 rpm from NA to system-2.

• BSFC

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Simulation Results

A) Steady state results at WOT

• Compressor performance

- Increase in air flow rate and compressor efficiency at 1000, 1200 and 1600 rpm.

- At higher speeds drop in compressor flow rate due to energy tapping for battery charging.

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Simulation Results

A) Steady state results at WOT

• Turbine performance

- Increase in air flow rate and turbine efficiency at 1000, 1200 and 1600 rpm.

- This additional gas flow rate will helps us to reduce Turbo lag.

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Simulation Results

A) Steady state results at WOT

• E-charger Map

In e-charger compressor map,

- Compressor efficiency is about 35% to 40%.

- Response is much faster – smaller inertia.

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Simulation Results

A) Steady state results at WOT

• Waste Gate (WG) diameter

During energy recovery (battery charging),

a) WG diameter is reduced – More gas flows via turbine that extracts excess energy.

b) Drop in enthalpy used for re-charging the battery.

• Energy recovery using Waste Gate (WG)

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Simulation Results

B) Time to torque comparison at 1600rpm.

- Time to torque improvement of ~19.62% is observed for electrically powered compressor (0.975 sec.)

than the conventional turbocharger (1.21 sec.).

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Simulation Results

C) Transient state results - NEDC

• Engine Torque

˗ Improvement in Torque because of additional mass flow supplied by E-charger.

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Simulation Results

C) Transient state results - NEDC

- An improvement in BSFC is 4.96% with E-charger over Turbo system.

• BSFC

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Simulation Results

C) Transient state results - NEDC

˗ The PMEP is improved with super charging system, this is one of the factor for the BSFC trend improvement.

• PMEP

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Simulation Results

C) Transient state results - NEDC

˗ Decrease in SOC is around 6%.

˗ E-charger is active for 435 sec over 1180 sec based on the logic – it is 37%.

˗ 50 A-h battery is used to support e-charger operation.

˗ Existing (12V battery) system is enough to support the e-charger module.

• Battery SOC

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Conclusion

Low End

Torque

• 92.06% @ 1600 rpm

BSFC• 6.64% @

1600 rpm

Time to Torque

• 19.62% over NEDC cycle

BSFC• 4.96% over

NEDC cycle

Performance of uprated engine

NA engine to e-charger charger

˗ Two different types of charging systems [system 1(Turbo) and system 2 (e-charger)] to uprate the N.A engine

performance are studied.

At WOT condition

Transient condition

Turbocharger engine to e-charger charger

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References

˗ [1] Prasad Sajjan Divekar, Beshah Ayalew and Robert Prucka., “Coordinated Electric Supercharging and

Turbo-Generation for a Diesel Engine”, SAE Technical Paper, 2010-01-1228, 2010.

˗ [2] P.Pallotti, E.Torella, J.New, M.Criddle and J.Brown., “Application of an Electric Boosting System to a Small,

Four-Cylinder S.I. Engine”, SAE International 2003-32-0039, 2003.

˗ [3] Yukio Yamashita. et al., “Development of Electric Supercharger to Facilitate the Downsizing of Automobile

Engines”, Mitsubishi Heavy Industries Technical Review Vol.47 No. 4, 2010.

˗ [4] Byeongil AN. et al., “Development of Two-stage Electric Turbocharging system for Automobiles”, Mitsubishi

Heavy Industries Technical Review Vol.52 No. 1, 2015.

˗ [5] Alain Lefebvre, Stephane Guilain., “Transient response of a Turbocharged SI Engine with an electrical boost

pressure supply”, SAE, Japan, 2003-01-1844, 2003.

˗ [6] WATSON N., and JANOTA M.S., “Turbocharging the Internal Combustion Engine”, Wiley-Inter science, 1982.

˗ [7] HEYWOOD, J.B., “Internal Combustion Engine Fundamentals”, Mc Graw-Hill, Inc., 2011.

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Acknowledgement

We would like to acknowledge with gratitude, for their extended support provided to our work.

˗ Vinayaga Moorthy – DGM, RNTBCI.

˗ Srinivasan Seethapathy – Dy. Manager, Intake and Exhaust system, RNTBCI.

˗ Badrigari Manishankar – Senior Engineer, Battery Sizing, RNTBCI.

˗ Gamma Technologies – Global support team.

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Queries ?