Bosch is the first company which
developed Common rail engine in the world in 1997.
Bosch developed up-to-date diesel engine that is environmental-friendly
and improved problem of noise and environmental pollution, output
that diesel engine has.
This common rail engine store fuel to common rail that is high
pressure fuel storage, is the method of fuel injection at high
pressure more than constant pressure, is diesel engine that inject
ultra high pressure.
General diesel engines must generate pressure
again every time, but common rail engine always keeps constant
pressure regardless of injection order. This pressure was kept
changelessly along fuel line.
Electronic timing of engine controls injection
pressure according to engine rate and load. ECU recontrol injection
pressure for the base of data that is gotten from cam and crank
sensor, and makes compression and injection work independently.This
technology can reduce fuel consumption and exhaust gas to permit
as can inject fuel according to need.
For this, it is needed special combustor to keep injection pressure
more than 1350 bars.Hereupon, Common fuel rail is introduced.
4 injection nozzles were connected on tip of high speed solenoid
controlled valve. Micro-computer reconciles time that valve opens
and indeed, decides whether need how many outputs and quantity
of fuel that is spouted according to operating conditions of engine.
At the moment of solenoid controlled valve is closed, fuel injection
stops.
High pressurization of Diesel fuel injection device
is important in making blending air of good quality in direct
injection small diesel engine. contributes in reduction harmful
exhausted gas and controls fuel injection time through electronization,
can secure higher degree of freedom than existent fuel injection
system in engine driving area, .Accordingly, can control discharge
rate of optimum injection timing, can reduce NOx (nitrogen oxide)
and PM (particulate matter, Black lead).
Bosch upgraded product to 1st generation, 2nd
generation, 3rd generation and can realize a low pollution, low
noise with exact injection by ECU(electric control unit) with
fuel injection pressure that arrives to average about 1600 bars
Common rail can control various harmful exhausted
gases consuming injected fuel nearly to perfect combustion.As
keep uniformity NOx level , can reduce exhausted particle to 60%,
HC 50%, CO 40%,CO2 20%, and to satisfy EURO III & US98, can
reduce by injecting before/after main injector Nox (nitrogen)
.Also, than engine that use existent rotary pump, can increase
fuel efficiency about 20% by doing maximization A/F.
As injection pressure of common rail is not related
to the engine speed and loading condition, high injection pressure
is possible when it is loaded much in low speed, it can acquire
torque 50% and output 25% more than general diesel engine
Injector: 각각의 실린더에 pilot 및 post분사 가능Rail: 제 1세대에서
1350bar, 제 2세대에서 1600bar 까지 축압 가능한 분사전 저장소High pressure pump: Rail로
연료 공급 하는 고압 펌프ECU: 엔진 운영 및 차량의 기능 통제 및 수행Sensors: 공기질량 (HFM5), 엔진속도
(회전수), 캠축, 온도를 통한 운전자 요구 수행 등의 측정을 위한 주요 센서들
Advantages of Common rail system
Decreasing harmful exhausted
gas
커먼레일 장치는 분사연료를 완전연소에 가깝게 소모시켜 각종 유해 배출가스를 억제할 수 있다. 동일 NOx 수준을
유지하면서 CO2 20%, CO 40%, HC 50% & 입자상 배출물을 60% 까지 줄일수 있고, EURO
III & US98를 만족하기 위하여 메인 인젝터 전/후에 분사를 함으로 인하여 NOx를 줄일수있다.
Increasing fuel efficiency
기존의 로타리 펌프를 사용하는 엔진에 비하여 A/F를 최대화하여 20% 정도의 연비향상을 이룰수 있다.
Increasing output of engine
분사압력은 엔진속도 및 부하 조건과 무관하기에 저속에서 부하가 많이 걸릴때는 고 분사압력가 가능하므로 기존에 사용되는
일반적인 디젤엔진보다 저속에서 토크 50% 향상 및 출력 25%의 증가를 얻어낼수 있음.
Comfortable driving sense
지금까지 디젤엔진의 특징이라고 불리우던 진동,소음을 파이롯트 분사의 도입으로 인하여 획기적으로 줄임으로서 운전하는데
보다나은 안락감을 얻을수 있으며, 가솔린 엔진과 같은 느낌을 받을수 있음.
컴팩트한 설계 & 경량화
인젝터를 컴팩트화 하여 2밸브 및 4밸브 적용가능하며 기존의 디젤엔진에 비하여 약 20Kg의 중량절감이 된다.
Module system
전자적으로 각 엔진 실린더별로분사가 가능하므로 시스템이 모듈화가 가능하며 3,4,5,6 실린더 엔진의 적용이 가능하다.
엔진의 큰 변경없이 컨벤셔널한 인젝션 장착을 커먼레일 시스템으로 대체가능하다.
