| 摘要 |
<p>Present day diesel engines having aluminum piston assemblies are limited to combustion chamber pressures of approximately 12,410 kPa (1,800 psi) whereas the desire is to increase such pressures up to the 15,170 kPa (2,200 psi) range. To reach such levels the instant piston assembly (76) includes a steel piston member (78) having an upper cylindrical portion (96) of a diameter ''D'' and a compression height ''CH''. The ratio of the compression height ''CH'' to the diameter ''D'' being within the range of from 60 % to 45 %. The piston member (78) is preferably forged and subsequently machined to precisely controllable dimensions. Moreover, the piston assembly (78) is preferably of the articulated type and includes a forged aluminum piston skirt (80) connected to the piston member (78) through a common wrist pin (82). Engine manufacturers are also demanding a smaller engine package size while retaining power output, improve fuel consumption and decreased emissions. The subject piston member (76) provides a simple and inexpensive solution to the increased power output package size relationship. To insure a small engine package, the piston member (78) has a compression height to maximum diameter ratio within the range of from 60 % to 45 %. The piston member (78) is preferably made from a steel forging to insure a reduced porosity over that of existing standard castings.</p> |
