Determination of a turbocharged gasoline engine for hybrid ... · Powertrain Concepts Modeling & Simulation Head of Department: Dr.-Ing. Sebastian Grams Project Manager: Dr.-Ing

Determination of a turbocharged gasoline

engine for hybrid powertrains F. Kercher, 26.10.2015

2 Determination of a turbocharged gasoline engine for hybrid powertrains | F. Kercher, I/EA-725 | 26.10.2015

► Introduction

► Hybrid Electric Vehicles (HEV)

► Investigated concept

► ICE adaption

► Results

► Conclusion and future outlook

Agenda

Determination of a turbocharged gasoline engine for hybrid powertrains


Introduction Dynamics of aggregats in hybrid powertrains

Cooperation-Professorship: Prof. Dr.-Ing. Michael Bargende Postgraduate: Hr. Felix Kercher

Department: Powertrain Concepts Modeling & Simulation Head of Department: Dr.-Ing. Sebastian Grams Project Manager: Dr.-Ing. Michael Auerbach


Hybrid Electric Vehicles (HEV) Powertrain portfolio

conventional powertrain

degree of electrification

hybrid powertrain

full electric powertrain

• Highly advanced ICEs

• ICE combined with EM

• Battery electric vehicles


direct injection:

• injection timing

• injected mass

tumble flap:

• position

throttle:

• angle

manifold injection:

• injection timing

• injected mass

spark plug:

• spark timing

Hybrid Electric Vehicles (HEV) Complexity in modern gasoline engines

wastegate actuator:

• position

valve train:

• cam phasing

• cam profile

gas exchange

thermodynamics


Hybrid Electric Vehicles (HEV) Complexity in modern gasoline engines

► Throttle angle

► Approx. 5 different angles

► Wastegate position

► Approx. 5 different positions

► Variable valve timing

► 15 different intake timings

► 15 different exhaust timings

► Variable cam profiles

► 2 intake profiles

► Tumble flap position

► 2 positions

► Dual mode injection system

► 2 types (DI or MPI)

► Approx. 10 different proportionings

► Variable spark timing

► Approx. 10 different spark timings

Overall about 2.250.000 combinations possible!!!


Hybrid Electric Vehicles (HEV) How to develop an ICE for a hybrid?

► Huge development efford needed in order to fit an existing ICE in hybrid powertrains

► 3D CFD

► Complex pre-processing

► Huge amount of time

needed to generate results

► Quality of results depending

on boundary conditions

► Experimental researches

► Expensive hardware

► Large workforce needed

► Reliable results

► 1D simulation

► Comprehensive

understanding of the

system possible

► Little manpower necessary

► Quick and reliable results

► Huge number of variations

can easily be handled


Investigated concept Serial hybrid

► Minimum of 3 power units required

► Energy generator (mostly ICE)

► Electric generator

► Electric traction motor

► ICE in serial powertrains

► Quasistationary operations

► Engine speed and load are not

directly affected by current

driving status

► Generator unit (Energy generator +

Electric generator)

► Efficency depends on

perfomance characteristics of

the units

chemical

electric


Investigated concept Development model for a serial hybrid

project timeline d

eg

ree

of

spe

cifi

cati

on

hardware matching

component adaption

control strategies

determination of operating

range

concept decision

determination of generator

unit efficencies

experimental validation


Investigated concept Determination of generator unit operating range

40 to 100% electric power

► Focus on high generator unit

efficiency

► Overlapping of the separate

best points at fixed ratio = 1

► Different torque levels of EM

and ICE lead to best efficiency

for investigated concept

► Operation at best efficiency for

each electric power output


Investigated concept Simulation results in ICE operating range

D =

4°

CA

Intake Valve Timing

Exhaust Valve Timing

D =

6°

CA

WG Ratio (𝒎 WG/𝒎 exh)

20

pe

rce

nta

ge

po

ints

50% Burn Point

D =

8°

CA

Step 1: Increase compression ratio

Step 2: Adjusted turbocharger

Step 3: Fixed valve timing


ICE adaption 1D model with adaption steps

1.Increased compression ratio

2.Adjusted turbocharger

3.Fixed valve timing


ICE adaption Step 1: Increase of compression ratio (0.8 units)

Efficiency increase at optimal 50% burn point

Efficiency loss due to knock limitation


ICE adaption Step 2: Step 1 + Turbocharger adjustment

Overall benefits in efficiency due to lower exhaust gas back pressure

Decrease of residual gas fraction


ICE adaption Step 3: Step 1 + 2 + Fixed valve timing (adjusted)

Exhaust valve timing is adjusted to match the new turbocharger


Results Optimal efficiency operating lines

Base Adaption

Adjusted turbocharger and fixed valve timing lead to reduced low-end-torque

Map range with high efficiencies is widened


Determination of generator unit efficiencies

Base

Adaption


Conclusion and outlook

► Methodical approaches are needed for the development of future powertrains

► Power units in hybrid powertrains must be adapted in order to match the desired

goals

► 1D simulation is the prefered tool to handle and evaluate the complexity in internal

combustion engines

► Operating ranges of ICEs in serial hybrids can be significantly reduced

► Increased efficiency

► Reduced application effort

► The combined efficiency of a generator unit in a serial hybrid was raised by 2% over a

wide range of electric power

Thank you for your attention!

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Determination of a turbocharged gasoline engine for hybrid ... · Powertrain Concepts Modeling & Simulation Head of Department: Dr.-Ing. Sebastian Grams Project Manager: Dr.-Ing