| 摘要 |
PURPOSE:To permit the stable pilot injection by driving a valve piece for opening and closing a valve hole formed between a pump chamber and a fuel relief chamber by a piezoelectric element and setting the valve piece from the pump chamber side. CONSTITUTION:A valve hole 34 is formed onto a partitioning wall 33 for separating a pump chamber 11 and a fuel relief chamber 38. A valve piece 42 for opening and closing the valve hole 34 is driven by a piezoelectric element lamination body 45. When the piezoelectric element lamination body 45 is extended on the completion of pilot injection, the valve piece 42 opens the valve hole 34 and stops injection. When the piezoelectric element lamination body 45 is contracted, the valve piece 42 closes the valve hole 34, and the pressure in the pump chamber 11 increases again. Therefore, the capacity variation rate of the pump chamber, i.e., the fuel discharge quantity is made independent from the extension and contraction quantity of the piezoelectric element lamination body, and the pilot injection can be carried out stably.
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