| 摘要 |
PCT No. PCT/BR97/00035 Sec. 371 Date Mar. 19, 1999 Sec. 102(e) Date Mar. 19, 1999 PCT Filed Jun. 13, 1997 PCT Pub. No. WO97/48895 PCT Pub. Date Dec. 24, 1997A piston which has a diameter of about 70 to about 100 mm and which is preferably produced with a resistant, malleable alloy having low density (lower than about 3 g/cm3) and mechanical properties at high temperatures such that a yield stress greater than about 120 Mpa at temperatures of the order of 300 DEG C. to 350 DEG C. is obtained. In the preferred embodiment, the piston is a single piece piston, comprising a head portion of diameter D ranging from about 70 to about 100 mm and a skirt portion downwardly projected from the head portion and inside which is provided a pair of wrist pin bosses, each having a hole with a diameter d and axial extension L for bearing the articulating wrist pin of the piston. The embodiment described improves the efficiency that the piston gives to the engine because it maintains the piston resistance at high levels while reducing its weight such that the piston operates at a rate of at least about 17 grams of weight per each kilowatt of power for each engine cylinder. |
