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This model is developed based on the concept of Hiroyasu's multizone combustion model. It takes nozzle injection (spray) parameters, induction swirl, air and fuel composition into consideration. The models of zone velocity, air entrainment rate, fuel droplet evaporation rate, mixture combustion rate are upgraded according to the latest papers. Various parameters, such as cylinder pressure, heat release rate, NOx and soot emissions, etc. are simulated. The simulated zone velocity and spray tip penetration are compared with those computed by Hiroyasu. The simulation results show good agreement with the experimental data.

Engine misfire (total or partial) causes a negative effect on the engine power and the exhaust emissions such as HC, CO and NOx. Moreover, it causes damage to the three-way-catalyst(TWC) system permanently. So, Engine misfire should be detected and eliminated. This study introduces a new system concept which is detecting combustion misfire using breakdown voltage (BDV) characteristics between electrodes. The focus of this study is that the detection and decision of misfire criterion through the misfire intensity calculation with BDV signal, which is derived by the application of a high bias voltage (30kV) to the spark-plug gap in the engine continuously. This study is driven to check the relation among BDV signal and misfire intensity inside an engine cylinder.

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).

The effect of various intake compositions and intake pressure on combustion & emission characteristics has been investigated in a single cylinder direct injection diesel engine. The variation of intake composition is simulated using argon, nitrogen and carbon dioxide as intake air diluents, and a screw compressor is used to boost intake pressure up to 200KPa. All diluents are found to be effective in reducing NOx emissions when intake pressure is changed from 110KPa to 200Kpa. Smoke emissions are drastically increased by the addition of argon, moderately increased by the addition of nitrogen. However, the addition of carbon dioxide substantially reduces smoke emissions and NOx emissions simultaneously. At lower intake pressure, the effects of diluting intake air with argon, nitrogen and carbon dioxide on ignition delay are proportional to their specific heats respectively, whereas the addition of argon has almost no effect on ignition delay when intake pressure is higher than 150KPa.