• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.991-998
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• 2013

The fuel injection pipe of a common rail system used in a clean diesel vehicle plays a role in supplying fuel from a rail to the injector of each cylinder connecting the engine under a repeated internal pressure. The fuel injection pressure is increased to over 200 MPa for satisfying EU emission standards and improving fuel efficiency, and a heading process and an autofrettage process are required for preventing folding defects and improving fatigue life. In this study, the flow stress and SN data of the material of the pipe are obtained through a tensile test and a fatigue test. The heading process for checking the folding defects of pipe ends is performed by using FEA. Furthermore, the optimal design of the autofrettage process for improving fatigue life considering not only the compressive residual stresses of the inner surface but also the tensile residual stresses of the outer surfaces of the pipe under the repeated internal pressure is performed by using FEA. To verify the process design, fatigue analysis for the autofrettaged pipe is performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.498-503
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• 2012

It happens that the fuel is not injected when the driver doesn't push the acceleration pedal of vehicle with engine speed higher than 1,500rpm above the mid range of vehicle speed. This is called "fuel-cut function" and almost every modern vehicle is equipped with this function. This is activated frequently on the downhill area of highway and the quantity of vehicle-exhausted $CO_2$ gas can be zero on this area. With this fuel-cut function on the test highway, $CO_2$ gas from passenger car(2,000cc engine volume) can be reduced up to 4%. The fuel-cut function with CRUISE made in company AVL is simulated to find the most effective driving pattern on the downhill area. By simulating with CRUISE software, it is found that the lower limit of vehicle speed for fuel-cut should be raised to improve the fuel economy on the steeper downhill road. The fuel economy can be most economical when fuel-cut driving and reacceleration are completed on the section of downhill road.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.199-205
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• 2008

In this study, a system to measure continuously the fuel concentration in a steady flow rig on the basis of Rayleigh scattering is presented. The system can be employed to measure both the temporal and the spatial distribution. Also, it is possible to calibrate the system for the measurement of accurate absolute concentration. Firstly, the system was tested at a calibration chamber for the determination of scattering cross section from propane, butane, acetylene, Freon-12 and Genetron 143a. After this, the system was adapted to a steady flow rig to measure the temporal and spatial fuel concentration. The rig is composed of cylinder head, intake manifold, injector, and transparent cylinder which can simulate internal combustion engine. To cope with the problem of Mie scattering interference, a software filter was developed, which is based on the rise time and the time constant of the photomultiplier-amplifier system. The results show that LRS can provide useful informations about concentration field and the software filter is very effective method to remove Mie interference.