session 34 per stålhammar
Post on 13-Sep-2014
603 views
DESCRIPTION
TRANSCRIPT
AVL AdvancedSimulation Technologies
AVLInstrumentationand Test Systems
AVLPowertrainEngineering
Engineering
Testing
passenger cars 2-wheelers racing
construction agriculture commercial vehicle
locomotive marine power plants
AVL covers all customer S
egments
AVL covers all customer S
egments
What is AVL?
� MTC - Founded 1988
� Independent Company 1998
� In the AVL-group 2002
� Acquired GMPT Södertälje 2008
� Situated in Haninge, Södertäljeand Gothenburg
� Center Of Expertice for alternative fuels
� Notified Technical Service
� Accreditations
Japan TRIAS (2000)ISO 17025 (2001)ISO 9001 2000 (2001)
� ~ 200 Persons Employed
What is AVL Sweden?
BiBi--fuelfuel
Lean BurnLean BurnStoichiometricStoichiometric
Different Technologies for different applications
Methane Engine Technologies
Dedicated gas (monoDedicated gas (mono--fuel)fuel)
DualDual--fuelfuel
SI (Spark Ignited)SI (Spark Ignited) CI (Compression Ignited)CI (Compression Ignited)
�Possible to convert Diesel engine to Duel Fuel without major changes to base engine.
�Possible to continue running on Diesel if gas is not available.
�Higher efficiency compared to spark ignited gas engines.
�Possible to convert the engine back to original Diesel
�No spark plugs
Why Dual Fuel?
Dual Fuel - Diesel or Otto combustion?
Diesel
No throttle
Compression ignited
High compression ratio
Diffusion controlled combustion
Otto
Throttle to control A/F
Spark ignited
Knock limited compression ratio
Flame propagating controlled combustion
Dual Fuel (except DI gas)
Throttle to control A/F
Compression ignited
Knock limited compression ratio
Flame propagating controlled combustion
Crank case:- Safety relief valves for intake receiver
- Crankcase ventilation with gas detectionsensor
Cylinder head:- Cylinder-individual gasadmission valves
- Pilot fuel injectors- Increased turbulence- Valve seat material
Piston:- Reducedcompression ratio
- Bore increase
Liner:Bore increase
Camshaft:Int. & exh. cam profile
CR Pilot Diesel Injection:- Electrically-driven HP Pumps- Piping
Engine Control System:- Gas operation- Knock control- Wiring
Inlet manifold:ThrottleGas piping
Turbocharger: - Compressor Bypass /Waste-Gate / VTG
- Re-specify
Dual Fuel converted Diesel engine(Typical OEM solution for large engines)
Technical challenges with Dual Fuel
�Combustion chamber is not optimized for Otto combustion leading to high levels of Methane slip
� Throttle is needed, leading to decreased efficiency at part load. (increased pumping losses)
�Not possible/suitable to run gas at idle and low loads
�Not possible to run gas at full load (knock limitations)
Damages from knocking combustion in a retrofit Dual Fuel engine
Before knocking After knocking
DI gas systemDI gas system
Dual Fuel Technologies
Premixed gas systemPremixed gas system(Micro pilot ignition)
Picture Wärtsilä
Generally higher levels of HC (Methane) from crevices and flame quenching.
Knock limited performance on gas.
Possible to run 100% Diesel mode when gas is not available.
Demand throttle which leads to poor part load efficiency
More system suppliers than DI
Generally higher NOx than premixed depending on diffusion controlled combustion.
Better knock tolerance than premixed
Less HC from crevices
Limited performance on Diesel
Generally more expensive than Premixed systems
Premixed gas with Premixed gas with
diesel ignitiondiesel ignitionDI gas with DI gas with
diesel ignitiondiesel ignition
Dual Fuel Technologies
� High levels of unburnt methane
� Low exhaust temperature
� Cold start demands from EURO VI
Aftertreatment systems for Dual Fuel
Challanges
After treatment system
� Methane oxidation catalyst with high efficiency and
durability is needed from EURO III
� SCR or DPF/POC is probably needed for EURO VI
(maybe also for EURO V)
Dual fuel combustion propertiesfrom R&D project in Sweden
Dual Fuel Combustion
Earlier
pilot injection
Later
pilot injection
Examples of Duel Fuel System Suppliers
Bosch
Clean Air Power
Hardstaff
Westport
Dual Fuel system suppliers
Clean Air Power Secondary intercooler to enable higher power without knock
Dual Fuel system suppliers
Picture CAP
Hardstaff OIGI Dual Fuel Technology (Oil Ignition Gas Injection)
�2 injectors per cylinder –reduced duty cycle
�Injector layout to achieve sequential operation
�Point of injection close to each inlet valve
Dual Fuel system suppliers
Picture Hardstaff
Hardstaff Dual Fuel Technology (aftertreatment )
Dual Fuel system suppliers
Picture Hardstaff
Westport HPDI Dual fuel system (High Pressure Direct gas Injection)
Dual Fuel system suppliers
Picture Westport
Westport HPDI Dual fuel system
Dual Fuel system suppliers
Picture Hardstaff
� Dual Fuel combustion is more complex than
conventional.
� Dual Fuel enables new combustion strategies
� Dual Fuel has not yet shown its full potential in truck
applications
� Lack of legislation hamper further development
Conclusions
Dual Fuel Technologies