CO2 Reduction for Spark-Ignition Engines: Two Paths to Success

Leveraging Air Delivery and Fuel Injection Technologies to Improve Engine Efficiency

John E. Kirwan Delphi Powertrain Systems

High Level Gasoline Engine Technology Roadmap

PZEV Market Drivers: EURO 5 EURO 5+ Emissions & CARB CO2 EU 130g/km Fuel Economy US Senate CAFE EURO 6 EU 70g/km US CAFE Update
H2 DI-Engine CNG DI-Engine
Alternate cycles, VCR, camless

EU 95g/km

HCCI GDi Engine, DICP & VVA & eVCP Spray Stratified Boosted GDi Engines Spray Stratified GDi Engines Homogeneous, Boosted GDi Engines, DICP & VVA Homogeneous, Boosted GDi Engines, DICP Homogeneous GDi Hybrid Engines Homogeneous GDi Engines, VVT Alternate Fuel H2 Engine Alternate Fuel CNG, LPG Alternate Fuel Compatible Engine Flex fuel, E10-E100 Boosted PFI Engines Gasoline Hybrid Engine Gasoline Advanced PFI Engine, active VT, mixture motion, PZEV Gasoline PZEV (AIR)

2008

2010

2012

2014 2

2016

2018

2020

Future

Where Does the Fuel Energy Go?

Fuel Energy Available Heat Rejection
Combustion Inefficiency

Exhaust

Coolant
Engine Friction Pumping Losses Accessories

Indicated Work

Shaft Work

Transmission

Vehicle Consumption

Inertia Aero Drag Rolling Resistance

Source: Natl Acad Eng. (2002)

Where Does the Fuel Energy Go?

Fuel Energy Available Heat Rejection
Combustion Inefficiency

Exhaust

Coolant
Engine Friction Pumping Losses Accessories

Source: SAE 2003-01-0029

Indicated Work

Shaft Work

Transmission

Vehicle Consumption

Inertia Aero Drag Rolling Resistance

Source: Natl Acad Eng. (2002)

Where Does the Fuel Energy Go?

Fuel Energy Available Heat Rejection
Combustion Inefficiency

Exhaust Target Domain: Improve Net Engine Efficiency

Coolant
Engine Friction Pumping Losses Accessories

Indicated Work

Shaft Work

Transmission

Vehicle Consumption

Inertia Aero Drag Rolling Resistance

Source: Natl Acad Eng. (2002)

Fundamental SI Engine Control Parameters

Air
hTarget: Reduce pumping losses hMethods:
q Valvetrain Technologies 8 Variable Cam Phasing 8 Cylinder Deactivation 8 Variable Valve Lift q Turbo / Supercharging
Fuel Energy Available Heat Rejection
Combustion Inefficiency

Exhaust

Coolant
Engine Friction Pumping Losses Accessories

Source: SAE 2003-01-0029

Indicated Work

Shaft Work

Transmission

Vehicle Consumption

Inertia Aero Drag Rolling Resistance

Source: Natl Acad Eng. (2002)

Fuel
hTarget: Reduce heat rejection and pumping losses hMethods:
q Homogeneous Gasoline Direct Injection q Stratified Gasoline Direct Injection

Spark
hTarget: Proper timing minimizes heat rejection; advanced ignition systems can enable higher dilution combustion strategies
6

Valvetrain Technologies

Variable Cam Phasing

Functionality: Control air flow through valve timing to gain performance, emissions reduction and fuel economy Benefit
Application Type Acronym Schematic

Performance Fuel Economy

Emissions HC NOx

Intake Only

IVCP
Exhaust
TDC

4-7%
Intake

1-2%

15%

25%

Exhaust Only

EVCP
Exhaust
TDC

<1%
Intake

1-2%

15%

25%

Dual Independent (Intake + Exhaust)

DICP
Exhaust
TDC

5-8%
Intake

1-4%

30%

40%

Dual Equal

DECP
Exhaust Intake
TDC

<1%

1-2%

20%

30%

Variable Cam Phasing

Stator Rotor

Vane Cam Phaser

Variable Cam Phasing

Benefits
F u el C o n su m p tio n
- V C P can pro vid e 2 to 3 % b ette r B S F C vs E GR
90 88

Fuel Consumption

86 84 82 80 78 5

E x t. E G R

Inc reas ing EGR %

Torque
6% Increase 11% Increase

CVCP

lo w e r bsfc Inc reas ing O verlap

Low S p eed Light Lo ad

4 3 2 1 0

N Ox

Retard Advance
0 1000 2000 3000 4000 5000 6000 7000

Engine Speed

10

Variable Cam Phasing -- eVCP

Functionality su m p tio n F u el C o n
90 88

Fuel Consumption

Benefits 86 Rotor
CVCP

- V C P can pro motor provides ultra GR hElectric vid e 2 to 3 % b ette r B S F C vs Efast high authority phase shifting independent of engine oil pressure Stator
E x t. E G R
Inc reas ing EGR %

lo w e r hCam phasing available immediately during 84 bsfc start-up for cold start emissions and Inc reas ing 82 O with driveability improvement verlap stop-start Low S p eed 80 vehicles Light Lo ad hIncreased phase angle authority and phasing 78 5 2 1 rate 4enables3 advanced combustion 0 strategies N Ox Vane Cam Phaser (e.g., HCCI / CAI)

11

Cylinder Deactivation
Functionality
hDisables intake valves from select engine cylinders at lighter engine loads qLost motion between intake cam and valve

Benefits
h6 8% lower fuel consumption in 6-cyl and 8-cyl engines qDecreased engine throttling for reduced pumping work qDecreased surface area for reduced heat transfer to engine coolant
12

Source: SAE 2001-01-3591

Pumping work reduction

Cylinder Deactivation
Functionality Valve Lifter Hardware Animation Deactivation
hDisables intake valves from select engine cylinders at lighter engine loads

q Lost motion between intake cam and valve

Benefits
h6 8% Lower fuel consumption in 6-cyl and 8cyl engines
q Decreased engine throttling for reduced pumping work

13

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

Functionality
hVaries valve lift, duration and timing (with cam phasing) as a function of engine load to reduce pumping work losses either by discrete 2-step or continuously valve lift profiles (CVVL) hEnables greater flexibility in engine combustion by de-throttling and increased dilution capability
10
E xh a u s t

2-Step
Valve Lift (mm) 8 6 4 2
BD C

H ig h - L if t C am

TDC

L o w - L if t C am

0 270 360 450 540 C ra n k P o s itio n (C A D ) 630

GEMS 250a VVA Mechanism Valve Lift Curves

10
Actuator @ 0 Deg Actuator @ -1 Deg Actuator @ -2 Deg Actuator @ -3 Deg

CVVL

Actuator @ -4 Deg Actuator @ -5 Deg Actuator @ -6 Deg

Valve Lift (mm)

Actuator @ -7 Deg Actuator @ -8 Deg Actuator @ -9 Deg Actuator @ -10 Deg

0 90 120 150 180 210 240 270

Camshaft Rotation (Degrees CW)

14

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

Functionality
hVaries valve lift, duration and timing (with cam phasing) as a function of engine load to reduce pumping work losses either by discrete 2-step or continuously valve lift profiles (CVVL) hEnables greater flexibility in engine combustion by de-throttling and increased dilution capability

Source: SAE 2003-01-0029

Benefits
h6 8% lower fuel consumption hHelps optimize E85 flex-fuel and HCCI combustion schemes

15

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

2-Step Example Hardware
Tri-Lobe Cam 2-Step Rocker Arm Oil Control Valve

Oil Supply Gallery

Valve Lift (mm)

Hydraulic Lash Adjuster

10
E xh a u s t

8 6 4 2 0 270
TDC L o w - L if t C am

H ig h - L if t C am

Higher load

Lower load

BDC

16

360 450 540 C r a n k P o s itio n (C A D )

630

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

2-Step Hardware Animation

Lower load

17

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

CVVL Example Hardware
Input cam
10 8

GEMS 250a VVA Mechanism Valve Lift Curves

Actuator @ 0 Deg Actuator @ -1 Deg Actuator @ -2 Deg Actuator @ -3 Deg Actuator @ -4 Deg Actuator @ -5 Deg Actuator @ -6 Deg

Increasing load

Rocker/Output cam

Valve Lift (mm)

Actuator @ -7 Deg Actuator @ -8 Deg Actuator @ -9 Deg Actuator @ -10 Deg

Low lift High lift

0

Control shaft

90

120

150

180

210

240

270

Camshaft Rotation (Degrees CW)

18

Variable Valve Activation: 2-Step and Continuously Variable (CVVL)

CVVL Hardware Animation

19

Gasoline Direct Injection

Gasoline Direct Injection vs. Port Injection

Mechanization
hInjector tip in combustion chamber hFuel pressure increased from 400 kPa to 20+ MPa hSide-mount and central mount injection configurations PFI

Injector

Intake valve

GDi side mount GDi

Intake Port

GDi central mount

Injector Injector Piston Intake Port

21

Piston

Gasoline Direct Injection vs. Port Injection

Features
hIn-cylinder evaporation of finely atomized fuel spray
q Cools intake charge to increase volumetric efficiency and enable knock-free operation at higher cylinder pressures 8 Enabler for higher compression ratios, increased boost
Injector

PFI

hEnables both homogeneous and stratified combustion strategies GDi side mount GDi
Intake Port Injector Injector Piston

Intake valve

GDi central mount

Intake Port

22

Piston

Gasoline Direct Injection Homogeneous Systems

System Features
h Inwardly-opening, multi-hole GDi Injectors, fuel rail and engine-driven high pressure fuel pump h Injection during the intake stroke focused on complete vaporization and mixing of fuel and air h Stoichiometric operation allows emissions control via traditional 3-way exhaust catalyst h Reduced in-cylinder temperature enables increased compression ratios (NA) or engine boosting

Low Pressure Lines

High Pressure Lines Pressure Sensor

Fuel Rail

Injector

23
High Pressure Pump

Wiring Harness and Connectors

Gasoline Direct Injection Homogeneous Systems

System Features
h Inwardly-opening, multi-hole GDi Injectors, fuel rail and engine-driven high pressure fuel pump h Stoichiometric operation allows emissions control via traditional 3-way exhaust catalyst h Reduced in-cylinder temperature enables increased compression ratios (NA) or engine boosting

Source: Knigstein et al (GM): 2008 Vienna Motor Symposium

1.8L engine downsized to 1.4L turbo (with down-speeding) 11% fuel consumption reduction Equivalent performance

Benefits
h Fuel economy improvement q 1-3% for naturally aspirated q 9-12% with downsizing and boost h Improved fuel control and rapid catalyst light-off with split-injection during cold start h Increased power and torque

24
Source: Schame (Ford): 2008 SAE Congress Presentation

Gasoline Direct Injection Homogeneous Systems

Key Requirements
hOperation at fuel pressures up to 200 bar hInjector packaging for cylinder side mount and central mount hSpray generation for good vaporization and mixing without wetting in-cylinder surfaces hGood linear flow range

Side mount

Central mount Up to 190 mm long

Injector Linear Flow Range Comparison

Deviation from Linear
20% 15% 10% 5% 0% -5%0 -10% -15%
0 10

Competition Ecotec Bosch DelphiDelphi Bravo

20

30

40

50

Flow (mg/pulse)

25

Gasoline Direct Injection Stratified Systems

System Features
h Outwardly-opening, hollow-cone GDi Injectors, fuel rail and engine-driven high pressure fuel pump h Central mount injector near spark plug h Injection during the compression stroke for careful placement of fuel mixture in space and time
q Multiple injections required to improve confinement of fuel mixture

Recirculation Zone

h Stratified fuel mixture enables unthrottled operation h Reduced in-cylinder temperature enables increased compression ratios (NA) or engine boosting

26

Gasoline Direct Injection Stratified Systems

System Features
NEDC CO2-Emission [g/km]
4 Cylinder Powered Vehicles in Germany

MPFI turbo

220

h Outwardly-opening, hollow-cone GDi Injectors, fuel rail and engine-driven high pressure fuel pump h Stratified mode allows unthrottled operation but CNG Gasoline 180 requires lean NOx reduction (NOx trap) q Euro vs US Nox emissions Gasoline NA q Low-sulfur fuel h Excellent synergy with turbocharging 140 h Reduces in-cylinder temperatures to enable increased compression ratios (NA) or engine Diesel Turbo boosting Turbo-diesel
100

DIG turbo, =1,0

Homog. Boosted GDi

DIG spray guided, >1,0 >

Stratified GDi

Benefits

40

60

80

100 120 Engine Power [kW]

140

160

h Fuel economy improvement q 10-15% for naturally aspirated q 15-20% with downsizing and boost h Improved fuel control and rapid catalyst light-off with split-injection during cold start h Increased power and torque 27

European strategy
h Current barriers to US implementation: q More stringent NOx standards q Lean NOx catalyst durability q Fuel sulfur concentration

Gasoline Direct Injection Stratified Systems

Key Requirements
hOperation at fuel pressures up to 200 bar hLow noise in critical frequency range hWell-atomized and well-placed stratified mixture under engine conditions hMultiple injection capability hHigh linear flow range
160 140
Fuel Mass (mg/shot)

Stable spray under engine conditions

5 bar 10 bar Backpressure 20 bar

fp = 200 bar

20% 15% Deviation (%) 10% 5% 0% -5% -10% -15%

120 100 80 60 40 20 0 0.00 1.00 2.00 3.00 Injector Pulse Width (ms) 4.00

-20% 5.00

28

Summary
Variable valvetrain technologies and gasoline direct injection offer technology improvements for two critical paths to CO2 reduction in SI engines
h Attack pumping losses and heat rejection to improve net engine efficiency h Can be used to optimize alternative fuel performance and advanced combustion strategies (e.g. HCCI / CAI, highly dilute combustion)

These innovations will substantially contribute to reducing fuel consumption required by Government and sought by customers
h Applicable to wide spectrum of engine sizes / power needs h Offer simultaneous performance benefits so that CO2 reduction need not conflict with fun-to-drive vehicles
Fuel Energy Available Heat Rejection
Combustion Inefficiency

Exhaust

Coolant
Engine Friction Pumping Losses Accessories

Source: SAE 2003-01-0029

Indicated Work

Shaft Work

Transmission

29

Vehicle Consumption

Inertia Aero Drag Rolling Resistance

Source: Natl Acad Eng. (2002)

Thank you

john.e.kirwan@delphi.com