Piston, Wristpin and Connecting Rod on inspection support

grabcad

A piston and connecting rod held up by a cylindrical spiralling support that meshes with the piston from below and supports it from underneath while the connecting rod hangs from the piston, suspended from the wrist pin.The software used to create the model was Autodesk 123d Design (now discontinued but can still be downloaded from : https://www.softpedia.com/get/science-cad/autodesk-123d.shtml ), and Moment of Inspiration 3D, which is commercially available cad modelling software (only used for part of the design process for the cylindrical, spiralling support). MOI3D was also used to export the .obj format files from the .step format CAD model files.Although entirely original and of my own design, the piston and connecting rod are broadly inspired by the design of Formula 1 engine pistons and connecting rods.As such the connecting rod is well reinforced to handle high tensile and compression forces (compression forces on the compression and power strokes of a 4 stroke engine and tensile forces on the exhaust and intake strokes). the connecting rod is also shorter than would be found in a lower performance or regular automotive engine, so as to achieve a higher high cylinder bore to stroke length ratio (necessary for high rpm, high power engines).The piston has as little inertial mass as possible without sacrificing structural integrity or resiliency. The side skirts are as as possible short to save inertial mass and are almost completely lacking on the sides of the piston which do not face significant lateral forces or side loading, especially during the compression or power strokes, driving the piston into the walls of the engine cylinder.On those sides of the piston, there is just enough piston wall to securely retain the piston rings that ensure as airtight a fit between the piston and cylinder wall as possible, to reduce or mitigate blow-by (which would cause the engine to produce less power than it is optimally capable of, increases pollution and fuel consumption and contaminates and degrades the engine's lubricant) as much as possible. The wrist pin is itself hollowed out as well, likewise to reduce reciprocating inertial mass which wastes power.The cylindrical, spiralling support with extensive cutouts extruded from it allows for good viewing angles without necessarily requiring that the piston and connecting rod be lifted off the support for a thorough inspection or review to be possible.The top of the piston is designed to facilitate good airflow and to be conducive to good air-fuel mixing before ignition as well as scavenging of exhaust gasses from the cylinder during the overlap between the exhaust and intake strokes, when both the intake and exhaust valves in the cylinder are partially open.The piston has a wedge shape crown resulting from extrusions cut out to accommodate the intake and exhaust valves in the top of the cylinder, in the cylinder head, which are arranged at an angle from vertical. This is necessary as the piston comes close to partially open valves as well as the cylinder head at the end of the compression and exhaust strokes.The piston underside has buttresses / webbing for reinforcement so its periphery doesn't collapse under compression forces. These transfer the compression and tensile forces to the middle of the piston, which is highly re-enforced and is where the wrist pin fits which forms the hinge between the piston and connecting rod.