Abstract
Exhaust gas from diesel engines includes diesel particulate. This air pollution problem must be solved early by from the standpoint of environmental preservation. The high-pressure injection for the atomization of fuel particle is very effective to improve combustion. On the other hand, the high-pressure injection increase the vibration of the fuel-injection pump system. This study investigates the vibration characteristics of the fuel injection pump body of the high-pressure type. Free damping vibration experiments by using an impulse hammer are carried out in order to investigate the dynamic characteristics . The natural frequency of each vibration mode by collating them in mode analysis is obtained from the experiments. On the other hand, a FEM model of an injection pump body is made in order to calculate the natural frequency of each vibration mode in the measurement frequency range from 1000 Hz to 4000 Hz. The FEM model is improved by the collation of the experiment values and the calculation values of natural frequencies. This FEM model is useful to reproduce the vibration displacements and stresses of the fuel injection pump body of each vibration mode. The vibration characteristics of the fuel injection pump of the high-pressure type are made clear by comparing the fuel injection pump body of the low-pressure type. Furthermore, the similar experiments and the FEM calculation are carried out for the body mounted with a bracket. It shows that these results are greatly different from the results of the simple body. In case of the body mounted with the bracket, the vibration characteristics of the high-pressure type are greatly different from those of the low-pressure type. One of the reasons owes to the mounting method between the body and the bracket. The bracket of the high-pressure type is united with the body but that of the low-pressure type is not united the body. In comparison with the vibration modes of the high-pressure type, those of the low-pressure have more mainly appeared in the low frequency region. The FEM calculation results show that the stress concentrates in the camshaft bearing support for either body. The combination of physical models of an advanced engine control system was proposed to obtain sophisticated combustion control in lean boost engines.
Physical models of intake, engine thermodynamic, combustion, inertia and transmission were incorporated. The control of air/fuel ratio, intake valve closing timing in the conditions of high boost and lean mixture, was investigated using simulations.