Essential Definitions of Mechanical and Pneumatic Components
Four-Stroke Engine Operation
The four-stroke engine operates through four distinct stages:
- Intake: Air enters the cylinder, mixing with atomized fuel.
- Compression: The air and fuel mixture is compressed by the upward movement of the piston.
- Power (Combustion): The burning fuel forces the piston downward with great force, producing useful work.
- Exhaust: The upward movement of the piston cleans the cylinder by expelling spent gases.
Two-Stroke Engine Mechanics
Two-stroke engines are piston engines where the complete work cycle is achieved with just one turn of the crankshaft. The stages involve simultaneous processes:
- Intake and Compression: Compressed air and gas enter the crankcase, creating a vacuum. This forces air inward and mixes it with new gasoline.
- Exhaust and Transfer: The piston uncovers a lateral port (skylight) communicating with the exterior. The pressure of the expanding gases forces them out of the cylinder.
- Transfer Completion: The piston continues moving, uncovering a lower port, which allows the entry of the compressed fresh mixture into the cylinder.
Wankel Rotary Engine Design
The Wankel engine utilizes a triangular rotor (piston) that rotates within a stator, dividing the space into three variable-volume chambers. It effectively performs three four-stroke cycles staggered by one-third of the rotor’s rotation. All three cycles occur in a single revolution of the crankshaft.
Cam Mechanism and Function
A Cam is a mechanical piece that revolves around a point other than its geometric center. As the cam rotates, it causes the rise or fall of a follower (or tappet). The opposite effect cannot be produced by the cam itself. The follower can be activated directly or indirectly to open any element.
The opening and closing of valves are synchronized using multiple cams mounted on a camshaft. Cams are commonly used in spark ignition engines.
Rack and Pinion Mechanism
This mechanism consists of a metal bar (the rack) with teeth on one edge, designed to engage with a sprocket (the pinion). This engagement converts circular motion into rectilinear motion, or vice versa. It is widely used in wheeled vehicles for steering systems.
Vise: Clamping Tool Definition
A Vise is a utensil used in carpentry, metalwork, and other trades. It comprises a fixed part attached to a workbench and a movable jaw operated by a screw. Objects are secured and clamped between these two parts for work.
Adjustable Wrench Function
An Adjustable Wrench is a tool, typically made of iron, whose handle incorporates a device (usually a worm screw) that, when rotated, opens and closes the two parts forming the head. This allows the tool to be adjusted precisely to fit various sizes of nuts or bolts.
Crank Handle and Motion Conversion
A Crank Handle or crank mechanism transforms reciprocating motion into rotational motion, or vice versa. The rotation of a crank causes the rectilinear motion of a piston rod. A connecting rod serves to unite the two pieces. This motion is often guided. In a compressor, an electric motor pushes and pulls the piston to compress the air.
Crankshaft: Linear to Circular Motion
A Crankshaft is a shaft featuring offset sections (cranks or elbows) that transforms linear (reciprocating) motion into circular motion. Crankshafts are employed in all types of mechanisms requiring synchronized alternative movements, such as car engines.
In an engine, the cranks are disposed angularly so that the resulting combustion forces are equally spaced, maximizing engine torque. They are regularly used in 4-cylinder cars and 6-cylinder trucks.
Gear Reducer System (Gearbox)
A Reducer is a gear system that allows the relationship between engine speed and the speed of the driven mobile component to be changed. While the engine and crankshaft turn at thousands of revolutions per minute, the gear ratio varies depending on the selected gear (marcha). For example, a bulldozer or tractor operates slower but generates significantly more force (torque).
Air Compressor Technology
A Compressor is a device used to compress a fluid, usually air, to a given pressure. There are two main categories of compressors: Volumetric and Turbo/Dynamic.
The compressed air is stored in an accumulator tank for use when needed. A compressor usually includes a safety valve to prevent excessive pressure buildup by stopping the electric motor. Additionally, a pressure gauge allows the operator to read the current pressure level.
Pneumatic Actuator Cylinder
An Acting Cylinder uses compressed air to produce movement and force. When the control valve is actuated, compressed air enters one side of the cylinder, forcing the piston (or plunger) to move. The air on the other side exits through the exhaust port.
3/2 Way Pneumatic Valve
This valve allows the operator to choose between introducing air from the compressor or exhausting air from a pipe. When the button is pressed, the internal mechanism slides, allowing the entry of air.
Flow Control Regulator Valve
This valve features an adjustable screw that reduces the passage of air. This mechanism is used to precisely adjust the speed of the cylinder actuator.
Check Valve (Non-Return Valve)
A Check Valve prevents air that has been introduced into the circuit from flowing back out when the compressor stops. Regulator valves often incorporate non-return functionality as well.
Pneumatic OR Logic Valve
The OR Logic Valve (Shuttle Valve) directs air into the cylinder if pressure is applied to either input, ensuring flow even if only one input is active.
Pneumatic AND Logic Valve
This valve allows air to pass only if both inputs are pressurized simultaneously. If there is no pressure on either input, the double piston remains centered, blocking flow. If pressure is applied to only one side, it pushes the double plunger to the opposite side, blocking the passage of the exit or entry port.
5/2 Way Pneumatic Valve
A 5/2 Way Valve is designed to connect two pipes from one side to three pipes on the other side in two distinct ways, controlling complex pneumatic circuits.
Pneumatically Actuated Valves
These are control valves that use pneumatic signals, often low-pressure inputs from the control circuit, to switch their operational state.