The Articulated Piston Pump

The Articulated Piston Pump

A two-piece piston composed of independent head and skirt portions, wherein the skirt portion is mounted by means of a wrist pin on bosses located on the lower end of members pending from the head portion, the head portion being provided with an annular recess between the combustion bowl and the ring zone, and the skirt provided with a tray on its upper end, the annular recess and the tray defining a semi-open cooling chamber. With the piston assembled, the lower end of the head portion below the ring zone and the upper end of the skirt portion, which constitutes the outer wall of the tray, define an oil baffle designed to prevent the cooling oil from flowing from the tray toward the space between the piston and the cylinder.,We are the largest producer of Projector Lamp products here.
The methodology allows the characterization of conventional and articulated piston secondary motions in the thrust plane of the cylinder. Motions of the piston, pin, rod and (for articulated pistons) skirt are separately calculated,Welcome to my home of Sky Lanterns, there are so many lanterns cheap. by integrating equations of motion for individual components and dynamic degrees of freedom. Various configurations with respect to rigid attachment of the wristpin to other components can also be represented. In the equations of motions solved, all gas pressure, inertia, friction and oil or contact pressure forces are accounted for. Detailed submodels of skirt and wristpin lubrication are utilized to calculate the effect of these oil films. All pertinent operating parameters (engine speed and cyclic pressure variation) as well as design parameters, such as component masses, moments of inertia,Description:2U compact fluorescent. mass centers, pin offsets etc.
The model was applied, in conjunction with the skirt and wristpin lubrication submodels, to conventional and articulated pistons, in a number of parametric studies. Effects of speed, load and piston configuration were investigated.
In the present days there is a growing tendency toward the use of articulated, or two-piece, pistons on diesel engines. In the articulated piston the head and the skirt are independent members: the skirt is assembled by means of a wrist pin on bosses located at the lower end of members depending from the head. With the piston fitted in the cylinder there is no contact between the head and the skirt portions. The basic feature of the articulated piston is that its components perform independent functions: the head, provided with the ring zone, bears the pressure of the combustion gases,product to table lamps at reasonable price,Our primary aim is to help the customers. while the skirt functions as a guide of the piston in the cylinder and supports the side loads transmitted by the inclination of the connecting rod.
The mounting of this type of piston in the cylinder can be made with small clearances due to the use of ferrous metals, which have a lower coefficient of thermal expansion, approximately that of the cylinder liner, which favors a better piston ring stability owing to a smaller lateral movement of the piston, thereby affording a lower lubricating oil consumption and a reduction of blow-by. Moreover, the absence of contact between the skirt and the head results in a reduced temperature on the skirt, thereby affording smaller mounting clearances and accordingly a decrease of the piston noise level.
Generally, the top portion, or head, of articulated pistons is made of a ferrous metal which is more resistant to the high thermal and mechanical loads, the skirt being generally of a cast or forged aluminum alloy. The use of a ferrous metal for the head affords placing the upper compression ring groove very close to the piston top, which would be virtually impracticable on conventional aluminum alloy pistons.
On high output diesel engines, the high temperatures on the piston top, especially on the ring zone and combustion chamber, make these areas extremely susceptible to problems. On the ring zone, very high temperatures may cause an excessive and early wear of the upper compression ring groove, degradation of the lubricating oil, build-up of carbon deposits and ring sticking. On the combustion chamber, these problems are represented by thermal cracks which tend to propagate and ultimately cause a breakage of the piston top. Therefore, it is necessary to provide a decrease of temperature of these regions in order to solve this problem.