Advanced Development of Medium Speed Gas Engine Targeting to Marine Kazuhiro Yuki Niigata Power Systems Co., Ltd.
Background Nowadays, regulation of exhaust emission from engines is becoming more strict year by year in the marine field, and it is difficult to fulfill the regulation by diesel engine itself. Gas fuelled engines emit low NOx, therefore it is possible to satisfy the regulation by the engine itself. (One of solution) IMO NOx regulation [g/kwh h] 20% reduction 80% reduction NIIGATA s Gas engine Tier Ⅰ Tier Ⅱ Tier Ⅲ (ECA: Year 2016) Engine speed [min -1 ] 2
New Marine Gas Engine Gas-fueled engines for marine application Related to IMO NOx emission standards Niigata new gas engine is dual-fuel engine. The engine can operate as an ordinary diesel engine and also as a gas engine. Even if one of the gas supply components malfunctions while operating in the gas mode, the ship can continue running by switching the engine to the diesel mode. The dual-fuel engine provides redundancy for the ship s propulsion system, which is one of the most important features for safety operation. 3
New Marine Gas Engine Target of ships Engine speed [min-1] 800 600 400 200 One of operation pattern Z-peller Gas engine Engine speed [min-1] 0 800 600 400 200 12:00 12:30 13:00 13:30 14:00 0 Time [h:m] Maximum quick load increase in above operation pattern 15% to 100% load Quick load increase. 12:15 12:16 12:17 12:18 12:19 12:20 Time [h:m] LNG Tank Tugboat with direct drive in heaver is target. Quick load increase is demanded at tugboat operation. 4
Transient performance (Excess air ratio during acceleration) High Mean effectiv ve pressure(output) Knocking Operational zone Gas rich Accelerating Air-fuel ratio Misfire Steady operation Gas lean Lack of air can occur from the delay of T/C respondent or delay of excess air ratio adjustment. Lack of air causes Knocking. 5
New Marine Gas Engine Gas mode IMO NOx Tier III compliant Same load transition characteristics as current diesel engine Same output and flexible mode change between diesel and gas at any load Quick mode change to diesel mode in case emergency Knocking free operation Diesel mode IMO NOx Tier II compliant 6
Specification of Marine gas engine Items Developed engine Ignition method (gas mode) B.M.E.P. Fuel gas Fuel oil Specification 6L28AHX-DF Dual fuel engine Direct injection Micro pilot ignition 2.0 MPa LNG, NG (gas phase) MN=65 MDO 7
Key concept of ignition method Utilization of simulation for certain combustion Themicro pilot combustion by direct injection was achieved with the utilization of simulation, designing appropriate injector specification and combustion chamber. Gas Operation Pilot oil Fuel gas Gas admission valve Direct injection Air 8
Quick load change operation Engine load [%] 120 100 Propeller direct drive 80 60 40 20 0 300 400 500 600 700 800 Engine speed [min-1] At quick load increase, turbocharger cannot supply a sufficient amount of air. Boost air flow Air flow at static operation Air flow at quick load change operation 300 400 500 600 700 800 Engine speed [min-1] 9
Air-fuel control Air-Fuel Controller Temp. Controller Water Valve Actuator Throttle Valve Bypass line Air Temp. Air cooler Turbocharger Charge air pressure Exhaust gas Engine load should be controlled by gas volume. Gas Valve Cylinder Fuel Gas Air-fuel ratio is controlled by the charge air temperature and pressure. 10
High Mean effectiv ve pressure(output) Transient performance (Excess air ratio during acceleration) Improvement of air flow Knocking Operational zone Gas rich Accelerating Air-fuel ratio Suppression of knocking Lack of air can Misfire occur from the delay of T/C respondent or delay of excess air ratio adjustment. Steady operation Gas lean Lack of air causes Knocking. To improve transient performance, secure of sufficient air flow and suppression of knocking is necessary 11
Operation Operation concept Gas mode Normal Operation Normal Change Rapid Change Return Change Normal Change Diesel Mode Start Operation pattern Load 100% Clutch ON Idle Stop Mode GE DE After Clutch ON DE to GE Load up operation during change over Emergency Idle operation Can keep GE Stop 100% load Change over Before stop GE to DE 12
Switching of engine operation mode Normal gas mode change Emergency diesel mode change Diesel mode Measureme ent data Gas mode Gas mode Time Engine speed Gas governor signal Diesel governor signal Diesel mode Time Realized mode change at 100% load 13
NOx emission characteristics IMO NOx emission standards New engine satisfied NOx emission for IMO Tier Ⅲ with gas mode and Tier Ⅱ with diesel mode. Quantity of emissions s Diesel engine Dual fuel engine (Gas mode) 100 100 81 Carbon dioxide (CO2) Tier Ⅱ 12 Nitrogen oxide (NOx) Tier Ⅲ ] h / g o t d n o p s e r o c [ x O N ] h / g o t d n o p s e r o c [ 2 O C Diesel engine Dual fuel engine(gas mode) 0 25 50 75 100 Load [%] Diesel engine Dual fuel engine(gas mode) 0 25 50 75 100 Load [%] 14
Ship handling demonstration(tug tug boat) In Load FPP gas direct pattern mode, connection transient of a tug is boat, performance which needs comparable with rapid supported(with diesel transient engine marine performance, was gear) achieved. was tested. Rated output Engine speed Rated output Engine speed Diesel mode Rated output Engine speed Diesel mode Gas mode Gas mode Idle Idle Idle Elapsed time(min) Elapsed time(min) Elapsed time(min) 15
Conclusion In gas mode, finally NOx emission of IMO Tier Ⅲ was succeeded. Transient performance comparable to diesel engine was achieved in gas mode Niigata will deliver newly developed dual fuel engine to Japan s first LNG fuelled ship. This is the world s first built pure mechanical driven FPP LNG fuelled ship. Proffered NYK 16
Thank you for your attention. Acknowledgement The Dual Fuel marine propulsion engine 6L28AHX-DF introduced today uses part of technology from the research development which was selected as a supported project of Research project of CO2 reduction from marine vessels by Ministry of Land, Infrastructure, Transport and Tourism, selected as a supported project by Nippon Kaiji Kyoukai(Class NK), selected as a joint research with Japan Ship Technology research association and financially supported by the NIPPON Foundation. NIIGATA expresses sincere appreciation to these associations and foundation. 17