Numerical Simulation On The Performances And Emissions Of The Direct Injection Compression Ignition Engine

• Main Author: Yap, Mew Yaw
• Format: Monograph
• Language: English
• Published: Universiti Sains Malaysia 2019
• Subjects: T Technology; TJ Mechanical engineering and machinery
• Online Access: http://eprints.usm.my/58430/1/Numerical%20Simulation%20On%20The%20Performances%20And%20Emissions%20Of%20The%20Direct%20Injection%20Compression%20Ignition%20Engine.pdf; http://eprints.usm.my/58430/

In order to improve the efficiency of the diesel engine, a lot of works and studies had been done. In this project, the effects of engine speeds and the injection timings on the physical behaviour in cylinder process in a diesel engine will be investigated. This study stresses on the peak pressure, heat release rate, temperature, turbulent kinetic energy and mass fraction of NOx in the cylinder. Research works employing experimental methods need extensive investment in terms of man power, cost, time and high technology device. Thus, the simulation software i.e. ANSYS Fluent, can be used to carry out a study on the performances and emissions of a diesel engine. The simulation can be conducted repeatly by chainging the engine speeds (2000rpm, 2500rpm and 3000rpm) and injection timings (CA10 BTDC, CA15 BTDC and CA17 BTDC) using eddy dissipation model. Parameters such as CA, spray angle valve timing, injection velocity and injected mass are fixed in this study. The base line case was running at 2500rpm with injection timing of CA15 BTDC. All the engine parameters were taken from the actual engine model of 4TNV98CT-GGE. In addition, simulations results showed that lower engine speed give rise to higher peak cylinder pressure, HRR and temperature. Due to the high air temperature, the mass fraction of NOx is also higher due to the high air temperature. The results also show that a delay injection time would yield lower the peak pressure, HRR and temperature because of the less combustion. Moreover, the contours of static pressure, static temperature, velocity magnitude can also be examined using the numerical software. In addition, this study shows clear trends of peak cylinder pressure, HRR, temperature, mass fraction of NOx. At engine speed of 2000rpm or injection timing of CA17 BTDC, the peak pressure and peak HRR are the highest for this diesel engine which are 4864833Pa and 75J/Degree respectively. A HRR peak will yield higher power output.