hcci engine

Strategies to control combustion in Strategies to control combustion in HCCI engines: Modelling InvestigationsHCCI engines: Modelling Investigations

Ali M. AldawoodAli M. Aldawood

Supervisor: Dr Markus KraftSupervisor: Dr Markus Kraft

Ali M Aldawoodama44@cam.ac.uk

HCCI Engine

Ali M Aldawoodama44@cam.ac.uk

Control Problem in HCCI Engine

Engine load

Adv

ance

C

ombu

stio

n st

art

R

etar

d

SOC

Ali M Aldawoodama44@cam.ac.uk

Control Problem in HCCI Engine

Engine load

Adv

ance

C

ombu

stio

n st

art

R

etar

d

Knocking limit

Misfire area

SOC

Ali M Aldawoodama44@cam.ac.uk

Control Problem in HCCI Engine

Engine load

Upper load

Lower load

Adv

ance

C

ombu

stio

n st

art

R

etar

d

Knocking limit

Misfire area

SOC

Operating window

Ali M Aldawoodama44@cam.ac.uk

Control Problem in HCCI Engine

Engine load

Adv

ance

C

ombu

stio

n st

art

R

etar

d

Knocking limit

Misfire area

SOC

Controlled timing

Ali M Aldawoodama44@cam.ac.uk

Investigate two fuel-based strategies to control the combustion timing

Detailed-chemistry, full-cycle model to simulate a single-cylinder HCCI engine

Closed-loop control of combustion timing using octane number or hydrogen ratio

Purpose of Study

Engine load

Knocking limit

Misfire area

SOC

Ad

van

ce

Co

mb

ust

ion

sta

rt

Re

tard

Controlled timing

Ali M Aldawoodama44@cam.ac.uk

Sandia’s Cummins Sandia’s Cummins Diesel EngineDiesel Engine

Modelled Engine

Ali M Aldawoodama44@cam.ac.uk

Coupling GT-Power with SRM

Intake Compression Power Exhaust

GT-Power Stochastic Reactor Model GT-Power

Closed-Volume

EVO

0o 180o 360o 540o 720o

Firing TDC

IVC

GT-Power simulates the open-volume (intake and exhaust) portion of the cycle

SRM simulates the closed-volume (compression, combustion and expansion) portion of the cycle

Pressure

Ali M Aldawoodama44@cam.ac.uk

Octane Number & Hydrogen Control

A closed-loop controller is integrated in the model.

Either octane number or hydrogen ratio is varied to control the combustion phasing.

Ali M Aldawoodama44@cam.ac.uk

Octane Number & Hydrogen Control

A closed-loop controller is integrated in the model.

Either octane number or hydrogen ratio is varied to control the combustion phasing.

Ali M Aldawoodama44@cam.ac.uk

Hydrogen Addition – Load Transients

3.5

4.0

4.5

5.0

5.5

6.0

6.5

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

BM

EP (

bar)

0.35

0.4

0.45

0.5

0.55

0.611 21 31 41 51 61 71 81

Cycles

Equi

vale

nce

ratio

Equivalence ratio

BMEP

3

5

7

9

11

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

CA50

(de

g ATD

C)

0.07

0.1

0.13

0.16

0.19

Hyd

roge

n ra

tio

Actual CA50 Target CA50

Controller output(hydrogen ratio)

Time (sec)

Ali M Aldawoodama44@cam.ac.uk

Conclusion

Full-cycle HCCI engine model is integrated with Full-cycle HCCI engine model is integrated with Stochastic Reactor Model and closed-loop Stochastic Reactor Model and closed-loop controlcontrol

Integrated model provided effective tool to Integrated model provided effective tool to simulate HCCI transients and investigate simulate HCCI transients and investigate combustion control strategiescombustion control strategies

Results suggest that both octane number and Results suggest that both octane number and hydrogen addition are effective for HCCI hydrogen addition are effective for HCCI combustion controlcombustion control

Ali M Aldawoodama44@cam.ac.uk

End of Presentation

Thank YouThank You