Subsystem Squeak & Rattle Analysis Using Altair’s Squeak and Rattle Director (SnRD)

Gasoline engine development using LOGEengine

Altair User ConferenceDetroit May 5th-7th

Fabian Mauss

LOGE AB

Altair User Conference, Dearborn 2

Outline

Motivation

Introduction to LOGEengine

Stochastic Reactor Model for Spark-Ignition gasoline engines

Model parameter extrapolation by the help of 3D CFD cold flowcalculations

Summary


Motivation

Fuel efficiency and emission legislation course high demands on the development of internal combustion engines.

Number of free engineering parameter increased significantly during the last decade.

Development efforts of gasoline engines. Fast and clean combustion with low cycle-to-cycle variation Improving the resistance to knocking combustion

Flame propagation

Combustion chamber design

Chemistry

Stochastic Reactor Model for SI engines (SI-SRM) Quasi-D flame propagation

Detailed chemistry

Low computational cost


LOGEengine: Introduction

LOGEengine applys a 0D – model to simulate processes in internal combustion engines.

Combustion

Abnormal combustion

Emission formation

LOGEengine helps to

Analyse existing engines

Prototype new engine development


SRM Local inhomogeneities in the gas phase

↘ Mixing time controls PDF development in time

Exhaust emissions

NOx, HC, CO, soot

Exhaust emissions

NOx, HC, CO, soot

Property

Mea

n v

alu

es

LOGEengine Stochastic Reactor Models


Aspects of internal combustion engine modelling

Computational cost [second/cycle]

Co

mp

lexi

ty [

cells

x s

pec

ies]

0D No spatial information No emission prediction ROHR & global

performance: IMEP Easy for systems

integration

QD Limited spatial information Limited emission prediction ROHR & global performance:

IMEP Easy for systems integration

3D CFD Detailed spatial

information Limited use of detailed

reaction mechanisms for emission prediction

Difficult for systems integration

QD SRM

Detailed chemistry↘ Emission prediction

Local inhomogeneities in the gas phase (Y, T)↘ Mixing process↘ QD-3D flame propagation

0D SRM

Tabulated chemistry

Next generation


LOGEengine Introduction

Heat Release Analysis

initial temperature

pressure offset

wall temperature

. . .

SRMs calibration

Mixing time history

Applications

Overview


Development Process

1. 3D CFD cold flow calculations

2. SI-SRM calibration using a representative mixing time

3. Parameter studies towards new concepts

Using the 3D CFD cold flow calculation the 0D SI-SRM can beparameterized for the prediction of the combustion processand knock occurrence in gasoline SI engines.


Concept of the 0D SI-SRM

1

n

T

L L

S uC

S S

Ll

u

Turbulent Flame Propagation model

LS

-calibration

Pre

ss

ure

[P

a]


Computational setup

Engine

Gasoline surrogate fuel

Primary reference fuel

Iso-Octane/n-Heptane (0.95/0.05)

Operating Point OP1 OP2 OP3*

Engine speed [1/min] 2000 3000 1500

IMEP [bar] 3.1 12.83 17.64

Lambda [-] 1.0 1.0 1.0

EGR [%] 35 11.5 2

*knocking combustion

Extracted from: Tsurushima, T., A new skeletal PRF kinetic model for HCCI combustion. Proceedings of the Combustion Institute, 2009. 32: p. 2835-2841


Validation of the flame propagation model with 3D CFD

M. Pasternak, F. Mauss, F. Xavier, M. Riess, M. Sens and A. Benz. 0D/3D Simulations of Combustion in Gasoline Engines Operated with Multiple Spark Plug Technology. SAE Paper 2015-01-1243

Single spark plug engine operation

Multiple spark plug engine operation


SI-SRM Parameterization using 3D CFD cold flow

Investigated engine operating points

Mixing time history for the SI-SRM using the data from 3D CFD cold flow simulations

I It

t

l l ku

u


SI-SRM Parameterization using 3D CFD cold flow

Baseline model validation (OP1)

Mixing time parameterization for the SI-SRM using the data from 3D CFD cold flow simulations CFD/SRM=5.3


SI-SRM validation with experimental data

Predicted in-cylinder pressure and rate of heat release based on CFD/SRM=5.3

Prediction of the combustion progressfor OP2 and OP3


Prediction of knocking combustion

Histories of in-cylinder pressure and mean temperature in the burned (Tb) and unburned (Tu) zone for OP3

Rate of heat release (RoHR-u) and species concentration in the unburned zone for OP3


SI-SRM for SI engines | Knocking combustion

Detection of knock occurence

intake temperature effects

heat release in endgas

detailed chemsitry consideration


Summary

We used 3D CFD cold flow data to extrapolate the SI-SRM parameter tosimulate the combustion process at different operating points

We report an accurate prediction of the combustion progress using quasi-3D treatment of the combustion chamber geometry and spherical flame propagation

Knocking combustion is predicted by the help of a detailed evaluation of the chemical processes

We propose a relatively simple development process at low computational cost (Complete run takes approximately 2 min on 1 CPU of computer desktop, using the 37 species reaction mechanism)