Notes, summaries, assignments, exams, and problems for Technology

Issue 31: Fuel Injection Power Systems

Food for Fuel Injection

This system supplies power to the combustion engine, replacing the carburetor with a system that injects gasoline directly into the air intake. Advantages of fuel injection systems:

• High performance
• Less fuel consumption
• Fast adaptation
• Reduced pollutants

Injection can be direct or indirect. Direct injection sprays fuel directly into the cylinder, maximizing engine power but requiring higher pressure. Indirect injection sprays gasoline into the intake manifold, with a simpler installation due to lower pressure requirements. Injection can also be continuous or discontinuous.

Mechanical Fuel Injection

Mechanical injection systems are powered by the internal combustion engine or lack an actuator.... Continue reading "Fuel Injection Power Systems: Operation and Types" »

Practical Work No. 7

Topic: Media Guided - Part 2

1. What are the physical media used in telecommunications networks that are mentioned in the text?
2. In reference to copper wires, what are the main variants that exist?
3. What are some of the major disadvantages of bare wire lines?
4. How are UTP cables used? Features of these cables provide each one of their technical characteristics.
5. What are underground multipair cables? What is their utility, and how is their isolation?
6. What are aerial multipair cables and what is their use?
7. What is Coaxial Cable? Depict it graphically.
8. What is referred to as the characteristic impedance of coaxial cables? What are the normal values of the characteristic impedance?
9. What is referred to as attenuation and what is its unit?
10. How

Axles

Axles are intended to support rotating bodies without turning the shaft itself. They are primarily subject to bending loads.

Shafts

Shafts are machine parts that always rotate with the components they support. They transmit power or torque and are subject to both torsion and bending loads. Shafts can be solid or hollow. When a keyway is present, consideration must be given to the shaft diameter due to stress concentration.

Bearings and Supports

Both axles and shafts require support points to bear their weight, facilitate rotation, and prevent displacement. Bearings are the components that provide these supports for shafts and axles.

Bearing Types

Friction Bearings

In friction bearings, the shaft or axle slides within the bearing surface. The... Continue reading "Axles, Shafts, Bearings, and Couplings" »

Mechanisms

Mechanisms are components used to transmit or transform movement. They can transmit linear motion, used for raising objects, or circular motion, used to change speed.

Levers

A lever is a rigid bar that pivots around a fixed point called a fulcrum. One end of the lever applies a force, while the other end moves a resistance.

Types of Levers

Depending on the positions of the fulcrum, force, and resistance, there are three types of levers:

• First-Class Lever

  The fulcrum is located between the force and the resistance. Example: Scissors, which are essentially two first-class levers joined together.

• Second-Class Lever

  The resistance is located between the fulcrum and the force. Example: Wheelbarrows.

• Third-Class Lever

  The force is located between

What are Plastics?

In chemistry and technology, plastics are polymeric organic materials. They are giant molecules formed by carbon atoms linked with hydrogen, oxygen, and to a lesser extent, chlorine, fluorine, nitrogen, or silicon.

Key Properties of Plastics

• Affordable
• Low density
• Waterproof
• Electrical insulators
• Thermal insulators, although not highly resistant to heat
• Resistant to corrosion and weathering
• Resistant to many chemical factors
• Some are recyclable, but not all are biodegradable or easily recycled
• Easy to work with
• Burning some plastics can be highly polluting

Origin of Plastics

Polymers can be classified based on their origin:

• Natural: Occur spontaneously in natural products like cellulose, rubber, and casein.
• Artificial: Industrially obtained

Engine Distribution System Fundamentals

The distribution system is the set of elements that perform the opening and closing of the valves. These valves control the entry and removal of gas in the cylinder, making possible the realization of the four strokes according to the distribution chart.

Key Components of the Valve Train

• Camshaft: Controls valve timing.
• Gears and Transmission System: Transfers motion from the crankshaft.
• Valves, Guides, Seats, and Springs: Control gas flow and ensure proper sealing.
• Pushers, Rockers, and Valve Adjustment System: Transmit motion to the valves.

Types of Valve Actuation Systems

Overhead Valve (OHV) Design

In the OHV system, the valves are located in the cylinder head, but the camshaft is located in the engine block.... Continue reading "Engine Valve Train Systems and Camshaft Drive Mechanisms" »

Mechanical Pumping System Components

Polished Rod

The polished rod bears the weight of the sucker rod string, the subsurface pump, and the fluid column within the tubing. Made of durable material, polished rods typically come in diameters of 1 1/4 and 1 1/2 inches, with lengths of 16 and 22 feet.

Subsurface Pumping System Components

Sucker Rod String

The sucker rod string transmits the reciprocating motion from the surface pumping unit to the subsurface pump. Available materials include steel, fiberglass, and continuous rods, each designed for different well depths, loads, and fluid conditions.

Subsurface Pump

The subsurface pump is a critical element in designing a mechanical pumping installation for a well. Its type, size, and placement significantly... Continue reading "Sucker Rod Pumping Systems: Components and Operational Considerations" »

Serrated cutting is a metal removal operation that can divide a piece into two or more parts by removing material between them. The manual process consists of the sawing and the forward movement of the saw. The effectiveness depends on operator skill and the number of sawing strokes per second.

Bow or Frame

This tool supports the saw blade. It consists of a rigid, U-shaped arch. At the ends of the arch are two mutually perpendicular blocks that hold the saw. One of these blocks is controlled by a mobile or wing nut, and a handle serves as a grip.

The arches of saws can be fixed or extensible. The advantage of the extensible type is that it allows the assembly of saw blades of various sizes.

Saw Blade

A saw blade is made of thin, laminated carbon... Continue reading "Serrated Cutting: Techniques and Tools for Metalworking" »

An annotation is the measure of a property of an object which must be specified in a technical drawing. Narrowing, also known as height or size, must meet a set of rules for readability and therefore facilitate the construction of a piece.

• Cota Lines: These are fine lines that indicate the exact size of each part of the piece. Are interrupted at its center for placement of dimensions or measures of that party. Thickness must be thin and an arrowhead. These indicate the beginning and end of each line. Dimension lines to be available so they are outside the contour of the piece.

• Cota Construction Lines: These are solid lines, which starting from the limit order to narrow space. Are drawn perpendicular to the dimension exceeds 1 or 2 mm. If the

Oil Tank Functions and Design

The oil tank, or reservoir, serves several critical functions in a hydraulic system.

Key Objectives of an Oil Tank

• Store System Fluid: To provide an adequate supply of hydraulic fluid for the system.
• Contaminant Settlement: To allow contaminants in suspension to settle out of the fluid.
• Temperature Regulation: To help maintain the fluid temperature within desired limits by dissipating heat.
• Air Dissipation: To facilitate the release of dissolved air or foam from the fluid.

Baffle Positioning in Oil Tanks

The position of baffles inside the tank is very important. Firstly, they establish separation between the suction line and the return line, preventing aerated or contaminated return oil from being immediately drawn back... Continue reading "Hydraulic System Components: Functions and Principles" »