Multicylinder Design for HCCI operation

William de Ojeda Alan Karkkainen International and Engine Corporation

Diesel Engine Development DOE DEER CONFERENCE Detroit, Michigan August 20-24, 2006

Acknowledgements: DOE LTC consortium project, Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion (DE-FC26­ 05NT42413) .

Industrial Partners: Jacobs Vehicle System, UCB, LLNL, Siemens, TM ConocoPhillips, BorgWarner, Mahle, Ricardo. Contents Development of a Multi- Diesel Engine for HCCI Operation

1. Objectives of Program Reconfigure ITEC V8 6.4L engine to operate on HCCI ITEC throughout the speed and load range. 6.4L 2. Engine Development (a) Based on “best” engine hardware, the engine lug curve is defined. (b) Optimization tools are applied to FIE, , cooling systems. (c) Control Strategy and hardware are developed to sustain combustion process based on cylinder pressure feedback. 3. Next Phase Engine Steady State Testing Transient operation Key Enabler Technologies

Loss motion valve control

Hardware: 1. Variable valve actuation system 2. Flexible FIE Spray 3. CAC with bypass and heater modeling 4. Cooled EGR 5. Two-stage turbocharger unit Simulation 1. Spray CFD analysis 2. Chemical Kinetics 3. 1-D Engine Performance Two-stage Control System turbocharger technology Engine Layout P8 P6 P4 P2

T8 T6 T4 T2

Tcharge Pcharge

FIE Pim Laboratory Set-up: IVC Tim CO2 CO 1. Establish overall manifold 2 Engine CO2 TBP TCAC temperature, boost control: IVC FIE a. Boost regulation T7 T5 T3 T1 emissions

b. CAC / heater control CAC P P P P Smoke 7 5 3 1 Heater c. EGR control NOx HC 2. Commence control over single CO EGR CO2 Texh T T cylinder to later expand to multi- Pexh w egr cylinder operation. Pc2 Tc2 V(reg) a. Validate single cylinder emission N probe b. Validate control diagnostics and N algorithms

Mair = f(DP) Tamb 3. Implement injection system Pamb

Tstack P 4. Implement turbocharger stack

Smoke 5. Implement cylinder head NOx HC CO 6. Implement VVA system CO2 Design Procedure Goal: 1. Define LTC conditions 2. Define Engine Torque and Performance 3. Define Engine Hardware Engine boundary 4. Optimize FIE conditions Φ, EGR 5. Establish Controls Supervisor Ma, Mf Φ ,EGR Ps, Ts reference Mf, Tivc, Pivc TQ curve Ma, Megr

CR, IVC Injection Hardware Engine Hardware optimization KIV (1) no. holes, size bowl A Selection (2) inj pressure – duration E

V (3) SOI

WA COMBUSTION SYSTEM AIR MANAGEMENT vaporization Mixture Piston, swirl Turbo VVA EGR / CAC coolers CR - VCR Inj press, Mf (duration) Multiple Injections SOI

Vaporized Φ CHEMKIN Homogeneous Controls Supervisor EGR Pcyl (TQ, SOC) , Boost Clean Mf VVA EGR Combustion SOI BOOST Prail CAC/HEATER Boundary Conditions

BCs are established based on: • Torque line • EGR and CAC specs • CR=14 • Φ = 0.4 • EGR rates 40-50%

With hardware requirements to yield: Max in-cylinder temperatures to sustain auto-ignition control (compression max temperatures of 900K) Capable turbocharger output Effects of IVC

Illustrated for rated condition Capabilities of IVC: • Lower in-cylinder temperatures, pressures

Penalties associated with IVC: • Extra boost required from compressor

Added Notes: Same effects obtained with varying the geometric without the associated penalties IVC gives the capability for cylinder-to-cylinder trimming Cylinder Head Optimization Performance at 30% flow over baseline cylinder head

Helical features 1. The middle light removed blue sticks show the original ports and the darker sticks are Port from the developed straightened flow box and widened 2. These sticks will be digitized and imported to CAD to update the cylinder head drawing. 3. The cylinder head will be recast and used in the HCCI engine testing. Short side radius modified Bench Marking Simulation Code

1. High speed Photography (top) is compared with KIVA modeling (below)

2. KIVA penetration estimates correlates well with “quiescent” conditions for conditions below.

3. Both compare well with estimates of Hirayasu.

400µs 600µs 12 hole 81 micron hole diameter Prail = 1600 bar, rho = 25 kg/m3, T= 293 K

60 measurements 50 KIVA simulation Hirayasu )

m 40 m n ( o i 30 at r t

ene 20 p

10

0 0 200 400 600 800 1000 1200 1400 1600 time (microsec)

800µs 1000µs Optimizing Mixture rated condition (3000 rpm, 12.4 bar) Spray Data: SOI = 120 BTDC Hole size affects homogeneity of mixture Histograms of Φ help determine the mixture formation Middle hole size (111µm) shows tighter histogram around average Φ 350º 330º 310º

Hole size 157 111 85

0.10 157micron 111micron 085 micron 350deg 0.09 330deg 310deg 0.08

0.07

0.06

F 0.05 PD 0.04

0.03

0.02

0.01

0.00 0.00 0.50 1.00 1.50 0.00 0.50 1.00 1.50 0.00 0.50 1.00 1.50 EQR EQR EQR Combustion – 3000 rpm Full Load Effect of SOI, Tin, EGR, other

Goal:

Optimize the heat SOI= -90 T= 370K 80 release curves to 40%EGR T= 370K maximize power 90 output and keep 100 peak in-cylinder 120 temperatures below NOx generation. Here, the effects of SOI, EGR and Temperature are SOI= -90 T= 400K pronounced. The 40%EGR BL insight is positive in regards to the capability to control each of these quantities. Control Strategy

Feedback criteria: BDC TDC 1. The engine under development 180º 0º will rely on a supervisor Light loads controller to adjust the FIE and (ignition trigger) Medium loads VVA systems on a cycle-to-cycle FIE FAST strategies High loads Cylinder or angle base. Pressure Feedback 2. The controller will also be able to adjust boost and EGR levels on a periodic base. ECR VVA 3. The controller is to demonstrate Slow BOOST VGT setting N,TQ it is capable to run at maximum Mapping speed (target 3600 rpm) with EGR setting + EGR% Transient capability to: adaptation

a. Process combustion To be EGR cooling assessed parameters (SOC, 50% burn, CAC cooling In early etc) phase CR CR~14-8 (lower b. Interface with auxiliary compression systems on a cycle-to-cycle temps) base. swirl Fixed

CN~40 (increase ID) Cylinder Timing Sequence

TDC BDC TDC BDC TDC

Comp Power Exhaust Comp Power Base IVC range line 591º IVC limit470º

CA 0 90 180 270 360 450 540 630 720 msec @3600 rpm 0 8.33 16.66 25.00 33.33

VVA controller

4º 1º 1º 4º SOI range

Early SOI ~ 120º BTDC

P(ө) acquisition window FIE P(ө) reduction and resolution controller LTC strategy VVA/FIE command output Summary

1. DESIGN AND PERFORMANCE: specifications were outlined for a production engine to operate with a low temperature combustion mode. Specifically: a. Target peak torque was set at 670 Nm at 2000 rpm (12.6 bar BMEP), rated set to 620 Nm at 3000 rpm, maximum engine speed set to 3600 rpm. The power output is within the target range proposed. b. Equivalence ratio targets are from 0.3 - 0.4 with EGR levels of 40 -50%.

2. HARDWARE DEFINITION: a. Compression ratio was set at 14. b. VVA concept was selected with flexible IVC, capable to control valves independently at each cylinder and cycle-to-cycle. c. A two-stage series turbocharger system with VGT turbines at each stage. d. FEI hardware was identified to yield optimum vaporization of fuel and adequate mixing. e. The base engine cylinder head was modified to improve the flow capacity into the engine. Improvements of 30% were attained with a final swirl of 0.5. 3. COMBUSTION SIMULATION provided heat release profiles, in-cylinder maps of temperature, equivalence ratio, soot, NOx. 4. CYLINDER PRESSURE BASED ALGORITHM execution is being benchmarked.