| Budget Amount *help |
¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2014: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Outline of Final Research Achievements |
In order to predict the water pressure fluctuation in the actual operation condition, the coupled vibration response of the engine structure and the cooling water acoustic field is calculated when the gas force, the piston slap force, the fuel injection pressure and the valve opening/closing force act on the engine structure. As a result, it was revealed that the maximum value of the cooling water pressure fluctuation is dominated by the piston slap. In addition, it was revealed that the pressure fluctuation peak value in the cooling water greatly changes when the underwater sound speed changes corresponding to the bubble content rate in the cooling water.
It has been found that the water pressure fluctuation becomes large when the natural frequency of the engine structure and the water pressure approaches. Furthermore, when the vibration mode of the cylinder liner at the piston impact point becomes large, the liner cavitation is easy to occurs on the wet surface of the cylinder
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