Operation Concept of a RI Engine Active radicals Early compression Sub-chamber Late compression Near TDC Flow into a Sub-chamber Spark Ignition in a Sub-chamber Ejection of Products Including Active Radicals Simultaneous Multi-ignition in a Main Chamber

Constant Volume Combustor

Comparison of RI and SI Methods 20 40 60 80 100 1 2 3 +5% -60% Overall burning time : Shorten by 60% Pmax : Increases by 5% Lean combustible limit : Extended by ER=0.25 RI method SI method Burning Pressure, MPa (with Sub-chamber) (without Sub-chamber) Ti=403K Pi=0.5MPa ER=0.8 Vs=4cc Dh=1.8mm*12 Time after spark signal, ms

Flame Visualization of SI and RI 12ms 31ms SI ER=1.0 7ms 18ms 25ms 38ms 44ms 8ms 30ms RI ER=0.8 7ms 9ms 20ms 41ms 47ms 10ms 17ms 22ms RI ER=1.0 7ms 13ms 26ms 32ms Time after ignition (10) (90-10) (Pmax)

Raw & Radical Images of RI (Vs=4cc, Dh=1.8㎜, ER=0.8) 3.0ms 5.0ms 6.0ms 11.0ms 15.0ms 18.0ms 4.0ms 9.0ms 25.0ms 34.0ms 37.0ms 40.0ms 24.0ms 27.0ms 31.0ms Raw CH Radical C2 Radical

Raw & Radical Images of SI ( ER=0.8 ) 14.0ms 20.0ms 30.0ms 40.0ms 50.0ms 60.0ms 10.0ms 55.0ms 65.0ms Raw CH Radical C2 Radical

Variation of Passage holes =30.54mm2

Combustion Pressure of RI at ER=0.8, Vs=2cc

Combustion Pressure of RI at ER=0.8, Vs=4cc

Combustion Pressure of RI at ER=0.8, Vs=7cc

Overall Combustion Duration versus Ah /Vs

RI-CNG Engine Operation Concept #2 Injector for CNG direct injection Close Open Close Residual gas Scavenging Rich mixture Lean mixture Late Exhaust Stroke Intake Stroke Compression Stroke ᆞ 부실 내 CNG 연료 직접분사로 잔류가스 소기 ᆞ 주실 및 부실 내 층상 희박혼합기의 형성 12

Experimental Apparatus #4 Electronic control unit (ECU) WTS, ATS, Encoder Pressure gauge High pressure regulator Solenoid safety valve Gas flow meter Ball valve CNG Surge tank Excess flow valve CNG injector UEGO O2 sensor UEGO sensor meter Air flow meter Sub-chamber Shut off valve Pressure transducer Active radicals CNG bombe Amp Exhaust gas analyzer PC A/D converter Engine Dynamometer 13

High pressure regulator Electronic control unit Plans in Future #17 Active radicals Sub-chamber injector UEGO O2 sensor UEGO sensor meter Exhaust gas analyzer Amp A/D converter PC Pressure transducer PFI injector CNG bombe Excess flow valve Surge tank Solenoid safety valve High pressure regulator Gas flow meter Air flow meter Needle valve Pressure gauge O2 O2 flow meter Shut off valve 2-way valve Electronic control unit (ECU) WTS, ATS, Encoder 분사시기에 따른 영향에 대해 설명한 것입니다. 흡입행정에서의 분사를 조기 분사라고 정의하였고, 후기 분사로 정의 하였습니다. 공기가 흡입되는 흡입 행정 중에 분사되기 때문에 흡입유동에 의해 균질혼합기를 형성할 것으로 판단하였고, 흡배기 밸브가 닫혀진 상태로 피스톤 캐비티 내로 분사되므로, 성층혼합기를 형성할 것으로 판단하였습니다. -다기통 엔진에의 적용과 기통당 배기량의 축소(약 350cc)로 연료분사기간의 단축 -출력용 PFI 분사와 부실 소기용 CNG 또는 O2의 미량 분사 제어

COVimep Variation with Excess Air Ratio(λ) #14

Experimental result of RI engine 1. PFI (Port Fuel Injection) : 분사시기가 비교적 자유롭다. 2. GDI (Gasoline Direct Injection or Gas Direct Injection)

Cylinder Pressure

Why cycle variations are occurred? partial burning, misfire, mixture motion, A/F ratio, residual gas fraction?

An examples of experimental results