hcci modelling progress

HCCI modelling progress

Sebastian Mosbach

20 March 2007

Sebastian Mosbachsm453@cam.ac.uk

The CoMo group at Cambridge

• Areas of application:

Engines Nanoparticles Particle processes

• Novel methods: Numerics, CFD, Quantum Chemistry, etc.

• Founded in 1999

• Headed by Dr. Markus Kraft

• Currently 22 members

Sebastian Mosbachsm453@cam.ac.uk

Dual Injection HCCI

Bore 95 mm

Stroke 115 mm

Displaced volume 815 cm3

Connecting rod length 210 mm

Compression ratio (CR) 11

Speed 1400 RPM

Fuel Gasoline

Air/fuel equivalence ratio 1.6

EGR ratio (internal+external) 20%

Inlet valve opening (IVO) 350 CAD ATDC

Inlet valve closing (IVC) 150 CAD BTDC

Exhaust valve opening (EVO) 120 CAD ATDC

Exhaust valve closing (EVC) 370 CAD ATDC

Start of first injection (SOI1) 340 CAD BTDC

Start of second injection (SOI2) 40 CAD BTDC

• Effect of charge stratification on maximum pressure rise rates

Int. J. Eng. Res., Feb. 2007

• Z. Wang, J.-X. Wang

Sebastian Mosbachsm453@cam.ac.uk

Dual Injection HCCI

• Evaporation of liquid fuel • Gaseous fuel mass fraction

Int. J. Eng. Res., Feb. 2007

Sebastian Mosbachsm453@cam.ac.uk

Dual Injection HCCI

• Parameter dependence of charge stratification level

Int. J. Eng. Res., Feb. 2007

Sebastian Mosbachsm453@cam.ac.uk

Dual Injection HCCI

• Higher stratification levels • Evolution of fluid parcels

Int. J. Eng. Res., Feb. 2007

Sebastian Mosbachsm453@cam.ac.uk

Partial charge stratification• Future work: Prediction of soot aggregates

• Particle size distributions

• Aggregate morphology

Sebastian Mosbachsm453@cam.ac.uk

Real-time transient simulation

• Full-cycle 1D CFD, GT-Power 6.2

• M. Sjöberg, J. Dec

• Problem: Computational expense

• Studies of transient engine operation, control, DOE, and optimization involve simulations over many cycles

• Solution: Storage/retrieval

Sebastian Mosbachsm453@cam.ac.uk

Example: Transient control

Sebastian Mosbachsm453@cam.ac.uk

Example: Transient control

• PID controller changes fuel composition (octane number) such that…

• Imposed equivalence ratio profile

• … ignition timing (CA50) is held at a given set point.

Sebastian Mosbachsm453@cam.ac.uk

Example: Transient control• Since SRM accounts

for inhomogeneities, turbulent mixing, and detailed chemical kinetics, can look at…

• maximum pressure rise rates,

• and emissions (e.g.)

Sebastian Mosbachsm453@cam.ac.uk

Example: Transient control

• Live simulation…