Effect of Fuel Injection Rate on Pollutant Emissions in DI Diesel Engine

Recent advanced technologies in diesel engine FIE(Fuel Injection Equipment) allow high pressure and multiple injection to be used to reduce particulate emissions without significant penalty in NOx emission. It is also well known that diesel engine particulate matter(PM) and NOx emissions can be reduced by the exact injection rate control according to engine conditions. This study was conducted based on such engine conditions as engine speed, load, swirl ratio and solenoid pulse timing and duration. The fast solenoid valve was installed between the connecting part of nozzle and fuel line. The ball valve driven by solenoid is open after the controller generates pulse and it spills the high pressure fuel in the high pressure nozzle chamber. Fuel line pressure, injection rate, cylinder pressure and exhaust emissions were measured with the variation of control method(pulse timing and pulse duration period). As a result, it is found that there are the optimum injection rates according to engine rpm and load.