A piston of an internal combustion engine includes a crown portion; a pair of thrust-side and counter-thrust-side skirt portions; and a pair of apron portions connecting the thrust-side skirt portion with the counter-thrust-side skirt portion. Each of the pair of apron portions includes an upper end wall connected with the crown portion, and a pin boss portion supporting a piston pin. A reverse-surface-side portion of the crown portion is formed with a hollow portion extending along an outer surface of the upper end wall of the apron portion. The upper end wall of the apron portion includes a bending portion between an outside surface of the pin boss portion and a circumferential end of the skirt portion. The bending portion bends in a step-like manner from the outside surface of the pin boss portion toward the circumferential end of the skirt portion.

Piston has crown portion 2 having crown surface 2a defining combustion chamber, thrust-side and anti-thrust-side skirt portions 3a, 3b formed integrally with crown portion and sliding on cylinder wall surface, a pair of apron portions 4a, 4a joined to skirt portions in circumferential direction, recessed portion 6 formed on back surface that is opposite side to crown surface and extending between skirt portions along substantially longitudinal direction, and a plurality of protrusions 7 formed integrally with bottom surface of recessed portion and extending along arrangement direction of skirt portions. At least one end edge in longitudinal direction of protrusion is integrally connected to inner side surface, facing one end edge of protrusion, of recessed portion. Adequate transcription performance to molding surface can therefore be ensured while removing remains of air on bottom side of recessed portion of mold for molding protrusions on crown portion back surface during casting.

A galleryless piston having a reduced weight and a reduced operating temperature is provided. The piston includes an undercrown surface exposed from an underside of the piston, a ring belt, pin bosses each presenting a pin bore, and skirt panels depending from the ring belt and coupled to the pin bosses by strut. The piston further includes an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels, the struts, and the pin bosses. The piston also includes outer pockets each extending along the undercrown surface and each surrounded by a portion of the ring belt, one of the pin bosses, and the struts coupling the one pin boss to the skirt panels. Cutouts are located in the pin bosses above the pin bores to increase the area of the undercrown surface and thus allow cooling oil to remove more heat from the undercrown surface.

A two-stroke engine piston (1) is disclosed comprising a piston top (3), a mantle surface (5), a stratified scavenging channel (7) in the mantle surface (5), and a weight reduction space (9) arranged between the piston top (3) and the stratified scavenging channel (7). The weight reduction space (9) has a largest first axial extent (a1) at the mantle surface (5) and a second axial extent (a2) radially inside the mantle surface (5), and wherein the second axial extent (a2) is greater than the largest first axial extent (a1). The present disclosure further relates to an engine (30), a hand-held tool (40), and a method of manufacturing an engine piston (1).

An improved piston forging for use in an internal combustion engine is disclosed. The piston forging comprises a crown, a pair of pin towers extending generally axially away from the crown, and a skirt extending generally axially away from the crown. The improved piston forging further comprises a plurality of grains flowing across the piston forging. The plurality of grains are reoriented during the forging operation into a configuration that follows the surfaces and features of the piston forging. More specifically, the plurality of grains are reoriented in a manner that is most beneficial to resist combustion and inertial forces that are enacted upon a machined piston during operation.

A one-piece cast piston (10) for an internal combustion engine includes a cooling channel (12) and at least one rib (18) on the inner side of the piston opposite the recess base of a combustion bowl (14).

A piston of an internal combustion engine may include a piston shaft and a piston head. The piston head may be provided with a closed cooling channel with a cooling medium arranged therein. The piston shaft may have a spherically round cross-sectional shape, wherein a deviation from the roundness with respect to a piston diameter may be less than 0.5 per thousand.

A proposed Adiabatic Diesel Engine (ADE), implements no cooling of the cylinders. The mechanism to achieve adiabatic cylinders is based on the separation of the crankcase mechanism from the cylinder mechanism. In an example implementation, the crankcase has a cross head mechanism driven by a connecting rod. The cross head mechanism drives the piston driveshaft(s) through a sliding bearing. The piston driveshaft moves between the crankcase and the cylinders. The cylinder has both a top where compression and combustion occur and a bottom with the piston driveshaft attached. The bottom has an opening for the piston driveshaft to move through. The bottom of the cylinder would normally be used to pump air for charging the combustion chamber. The crankcase mechanism contains lubricating oil and typically is cooled naturally through its casing.

[Problem to be Solved] A space from a skirt to a side wall is uniformly deformed in a wide range without a bias. [Solution] A piston 1 has two pin bosses 3 disposed so as to face each other at an interval, a side wall 4 disposed on both sides of the pin boss 3, and a skirt 5 provided continuously to the side wall 4, and a pin hole 3a into which a piston pin 1a can be inserted is formed in the pin boss 3. Inner walls 10 of the side wall 4 and the skirt 5 are continuous with each other and disposed by facing on both sides of a pin boss axis C1 with the pin boss axis C1 between them. A horizontal section of the inner wall 10 is formed along a specific oval shape E.

The present invention provides a power device generating greater propelling force and finds that traditional power devices do not include all propelling forces based on the fundamental core propelling force source problem. External pressure is guided to the traditional power devices since the inner speed is higher the outer speed, power consumption for overcoming fluid resistance is high, and mutual contradiction results are obtained. The unique difference between the present invention and general common sense lies in opposite fluid pressure directions; inner fluid channels and outer fluid channels with higher flow speeds are formed to generate pressure differences which guides the fluid pressure to the outside and serve as propelling force, thus the present invention creatively finds three propelling force sources, two lifting force or propelling force sources of helicopters or airplanes driven by propellers and two propelling force sources for sufficient burning of fuel in combustion chambers of engines.