Engine Optimization.

7/31/2019 Engine Optimization.

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Automotive Research Centerarc

Diesel Engine Optimization MethodologiesDiesel Engine Optimization Methodologies

NAC

Engine Optimization Methodologies:Engine Optimization Methodologies:

Tools and Strategies forTools and Strategies forDiesel Engine DesignDiesel Engine Design

George Delagrammatikas

Dennis Assanis, Zoran Filipi, Panos Papalambros,Nestor Michelena

The University of Michigan

May 24, 2000


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BACKGROUND:

VEHICLE AND ENGINEFUNDAMENTALS

ENGINE

TUNING

INVERSE

DESIGN

TARGET

CASCADING

CVT,

INJECTIONTIMINGS

MAP

SHAPINGAND

MATCHING

ENGINE FLEXIBILITY:

COMPRESSION RATIO,CVT,HYBRID

NOVELTECHNOLOGIES


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MotivationMotivation

Federal Regulations

Fuel economy (CAFE)

Emissions (NOx, smog, and other pollutants)

Public Awareness

Green movement

Global warming scare

Decrease Dependence on Foreign Oil Avoid another oil crisis


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ObjectivesObjectives Develop an engine optimization framework

21st century conventional and hybrid heavy truck

Implement techniques to conventional vehicle

Define a problem analytically

Apply suitable driving cycle(s)

Investigate location of use on engine map

Extend lessons learned to hybrid vehicle

How different are demands on engine andtransmission?

Need for a systems approach


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Euro III Steady State Test ProcedureEuro III Steady State Test Procedure


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Power Demands on EnginePower Demands on Engine

Torque,

Speedat Wheel

Torque,

Speedat EngineWHEEL ENGINE


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HEV System Simulation FrameworkHEV System Simulation Framework

ADVISOR

Matlab-SIMULINK environment

Parallel HEV

ENGINE FUEL DELIVERY

LOOK-UP TABLE

RPMTORQUE

FUEL (g/s)


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Baseline Vehicle ParametersBaseline Vehicle Parameters

Cummins M11-330 (246 kW) Diesel Engine

Wheel/axle assembly for heavy truck

Kenworth T400 Vehicle

Standard heavy vehicle accessory loads

Standard catalyst for CI engine

Eaton Fuller RTLO-12610B 10-Speed Transmission

Generic 10-spd constant efficiency gearbox

Heavy Vehicle Powertrain Control

Eaton Fuller RTLO-12610B 10-Speed Transmission

Generic 10-spd constant efficiency gearbox


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Baseline Cummins Engine MapBaseline Cummins Engine Map


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Driving Cycles InvestigatedDriving Cycles InvestigatedUS06 REP05

FHDSFUDS


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Engine Use Points for Various CyclesEngine Use Points for Various CyclesUS06 REP05

FHDSFUDS


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Power Frequency for Each CyclePower Frequency for Each CycleUS06 REP05

FHDSFUDS


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Out

putTorqu

e

Out

putTorqu

e

Engine SpeedEngine Speed

Ideal BSFC Line GenerationIdeal BSFC Line Generation


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Determine cumulative fuel throughput foreach cycle investigated

Interpolate BSFC from engine map for everytorque/speed combination for that given cycle

Integrate all BSFCs from above step

Find the total time that engine is producing power

Mean effective BSFC = total BSFC/engine on time

Benefits of Flexible Engine DesignsBenefits of Flexible Engine DesignsActual Transmission CaseActual Transmission Case


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Ideal BSFCIdeal BSFC vsvs. Power Level. Power Level

PowerPower

BSFC(g/k

W-hr)

BSFC(g/k

W-hr)


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Benefits of Flexible Engine DesignsBenefits of Flexible Engine DesignsIdeal Transmission CaseIdeal Transmission Case

Find ideal BSFC transmission line on enginemap used for a given cycle

Interpolate BSFC for every visited power level onthe BSFC vs. Power graph

Sum of all BSFCs is cumulative fuel throughput

Mean effective BSFC = numerical average of totalfuel throughput during time steps when engine is

active


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Potential Benefits of Ideal CVT DesignPotential Benefits of Ideal CVT Design

0

20

40

60

80

100

120

140

US06 REP05 FUDS FHDS

4*BSFCmin

2*BSFCmin

Increase

inMeanBSFCPerCycle

IncreaseinMeanBSFCPerCy

cle


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Optimum Injection Timing MethodOptimum Injection Timing Method

Using an optimization framework

Vary injection timing for every torque/speedcombination (over 200 map points, ~100 executionsper point)

Computationally prohibitive

Parallel computer framework

Run as many maps as you want at differentinjection timings

Coalesce data with a Matlab-based routineOne map = ~5 minutes


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Injection Timing MapsInjection Timing Maps

Engine SpeedEngine Speed

OutputTorque

OutputTorque


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Optimum Injection Timing MapOptimum Injection Timing Map

RPMRPMFuelingFueling

RateRate

Timing

Timing


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Variable Compression Ratio EngineVariable Compression Ratio Engine

Hypothetical investigation of novel enginedesign

Find the ideal fuel consumption benefit

Apply ideal transmission techniques from previousslides

Determine how BSFC can be optimized atvarious power levels

First maximize power density to find engines

power upper boundAllow engine controller to change parameters that

are not normally variable


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Problem FormulationProblem Formulation For each power level :

50, 100, 200, 300, 400, 500 kW

Minimize BSFC, subject to:overall phi < 0.6

20% < percent premixed burn < 40%

peak cylinder pressure < 150 bar

Variables:

Inlet manifold pressure

Compression ratioInjection timing

Fuel

Engine speed


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Same Engine - Different MapsSame Engine - Different Maps


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VCRE - Combined MapVCRE - Combined Map

RPMRPM

TOR

QUE

TOR

QUE


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Ideal BSFC Line vs. Power Level

170

180

190

200

210

220

230

240

50 100 150 200 250 300 350 400 450 500

Power (kW)

BSFC

(g/kW-hr)

vcre_bsfc

base_bsfc


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Hybrid Powertrain InvestigationsHybrid Powertrain Investigations


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Demands on Engine - CVT vs. 5-SpeedDemands on Engine - CVT vs. 5-Speed


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Demands on Motor - CVT vs. 5-SpeedDemands on Motor - CVT vs. 5-Speed


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Battery SOC - CVT vs. 5-SpeedBattery SOC - CVT vs. 5-Speed


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Zero Delta SOC - CVT vs. 5-SpeedZero Delta SOC - CVT vs. 5-Speed


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Additional Hybrid Clustering ScenariosAdditional Hybrid Clustering Scenarios

Power-Assist

Battery

Recharge

40

20

60


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Future DirectionsFuture Directions How realistic is the variable compression ratio

engine for the driving cycles and vehicles we areconsidering?

How can we better quantify the benefits ofincreased flexibility in transmission parameters?

What are the effects of injection timing andvariable valve timing on engine mapcharacteristics?

Is it better to cluster points around optimumpower levels on an engine map or disregard thatan engine can be described by a single map?


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Integration with Target CascadingIntegration with Target Cascading Parameterize engine torque curve

Maximize engine turndown ratio whilemeeting mobility constraints

Match maximum torque curve with a real

engine defined by high fidelity model Use engine visitation points in conjunction

with control strategies to meet BSFC and

emissions targets

Send results back to top level for verificationand subsequent iteration


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Parameterized Max Torque Curve - IParameterized Max Torque Curve - I


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Parameterized Max Torque Curve - IIParameterized Max Torque Curve - II


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Sample Torque CurvesSample Torque Curves

Min cluster area Min rated torque

Min rated power

A i R h C


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EngineEngineMatchingMatching

SubproblemSubproblem

A t ti R h C t


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ConclusionsConclusions

High fidelity engine model can be used atdifferent levels in the design process

Methods have been illustrated on a variety ofdifferent engines

Continue feed-backward work with ADVISORand extend methodology to VESIM

Engine Optimization.

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