What are Bidirectional transducers?

Bidirectional transducers are transducers in which the electrical quantity can be transformed into a non electrical quantity and vice versa.

Piezoelectric sensors are an example of bidirectional sensors. Force can be converted into an electrical signal. An electrical signal can also be converted into an physical movement or a force.

What is an inverse transducer ?

An inverse transducer is a transducer in which an electrical signal is converted into a non electrical quantity.

An example of an inverse transducer is a piezoelectric transducer in which an electrical signal can be converted into a movement or a vibration.

Electronic Fuel Injection

There is a vacuum-powered pressure regulator at the end of the fuel rail which ensures that the fuel pressure in the rail stays constant. Fuel injectors are connected with rail, but their valves remain closed until the ECU sends injection signal.

Usually, the injectors contain two pins. One pin is connected to the ECU. The ECU sends a pulsing ground to the injector, closing circuit. This lets the injector's solenoid get charged. The magnet on the plunger is attracted, opening the valve. The high pressure in the rail  starts fuel injection at a high velocity when the valve opens.

When the plunger rises, it opens a valve and the injector sends fuel just upstream of the intake valve, or straight into the cylinder. The first system is called multiport fuel injection and the latter is called direct injection.

The ECU decides the amount of fuel to inject into the cylinders to make the mixture stoichiometric.

Damper Pistons - An Overview

Dampers are convert parts of the kinetic energy of moving parts of a machine into thermal energy and thereby diminish the hard shocks or avoid too much oscillation amplitudes.

Dampers contain a pressure tube, a piston rod with a special piston system and the damping medium oil. The piston rod is submerged in the oil-filled pressure tube with its special seal and guiding system. This actually hermetically seals the inside compartment of the hydraulic damper from the atmosphere.

 The damping oil passes through the damping bores in the piston system via the movement of the piston rod. The damping forces thereby depend on the piston speed.

By closing the damping borings on both sides by valve washers, the damping forces are regulated in the direction of extension and compression. The damping force during compression decides the hardness of a shock absorber on retraction. The damping force on extension, on the other hand, regulates the extension speed.

Brake Linings

Brake linings is a layer of hard material affixed with the brake shoe or brake pad in order to increase friction against the drum or disc.

Brake linings are made of a relatively soft but wear-and-tear and heat-resistant material with a high coefficient of dynamic friction and also high coefficient of static friction. The linings are mounted to a solid metal structure using high-temperature adhesives or rivets. The complete assembly is then called a brake pad or brake shoe.

The dynamic friction coefficient "µ" for almost all of the brake pads is usually in the range of 0.35 to 0.42. In such a condition, a force of 1000 Newtons on the pad will give a resulting brake force close to 400 Newtons.

Some racing pads with a very high µ of 0.55 to 0.62 with excellent high-temperature properties are also available. These are high in iron content and they outperform other pads used with iron discs.

Aquaplaning or Hydroplaning - An Overview

Aquaplaning, or hydroplaning, takes place when the water between the tyre and  road cannot be removed quickly enough. This layer of water on the tyres stays until the pressure of the water overtakes the pressure of the tyre on the road, which may result in the tyres losing contact with the road surface. As a result, the vehicle can start to skid or spin.

The presence water can let your vehicle lose contact with the road surface. A tyre running through water creates a wave ahead of it. The tyre tread hitting the water at the front of the contact patch suffers an increase of the water pressure. When the water pressure becomes greater than the average pressure of the tyre on the road surface the tyre vehicle may lose control.

Therefore the water covering the tyre must be removed quickly through tyre design to avoid aquaplaning.

Anti Skid Brake System

Application of brake force on a vehicle wheel that is in normal contact with the pavement, results in the rubber of the tire beginning to stretch responding to friction heating and the force applied to the tire-pavement interface.

When brake force is applied, if the level of braking is increased to the levels of co-efficient of friction, mu, the wheel can no longer support the force being applied to the rubber, and hence the available stopping force begins to diminish.

Operation at the peak of the mu-slip offers the highest braking efficiency. Research suggests that a skid develops that may lock the wheel and blow the tire if unchecked.

Modern anti-skid brake control systems measure the speed of the wheel to find slip and developing a correction signal. The control unit finds out where the tire is operating on the mu-slip curve and sends a correction signal to the antiskid valve to reduce applied brake pressure. This helps the vehicle to avoid skidding.

Fuel Cells in Automobiles

A fuel cell automobile (FCA) or fuel cell electric automobile (FCEA) is an automobile which uses a fuel cell to power its on-board electric motor. Fuel cells in automobiles create electricity to provide power to an electric motor, generally using oxygen from the air and compressed hydrogen.

A fuel cell automobile that is fuelled with hydrogen exhausts only water and heat, but no tailpipe pollutants. Therefore it is considered a zero-emissions vehicle as well. Depending on the method, however, producing the required hydrogen used in the automobile creates pollutants.

Fuel cells are used in various kinds of vehicles including forklifts, especially in indoor applications where their clean emissions are important to air quality, and in space applications. Fuel cell technology has attracted a lot of attention and research spending in recent years.

Honda FCX Clarity, Hyundai Tucson Fuel Cell and Toyota Mirai are some examples of FCA.

Headlight Aimers - An Overview

A headlamp aimer is a means to check both the orientation and intensity of a vehicle headlamp. It is used to ensure that the headlamp meets a minimum standard for the country of use of the vehicle.

A headlight aimer comprises of a fully adjustable single optical collimated light lens assembly. This assembly is rail mounted and designed to prevent any distortion of the optical lens supporting structure during general use.

The optical lens is designed to accurately focus all types of vehicle headlamp. It is completely adjustable in the vertical plane; achieved by mounting it to a vertical column. The measurement travel of the optical lens used in the aimer is between the heights of 500mm and 1500mm, allowing the testing of all types of vehicles.

Finally, a mirror or laser at the top of the lens mounting column allows the headlight aimer to be aligned with the longitudinal axis of the presented vehicle.

Automatic Guided Vehicle Systems - An Overview

Automatic guided vehicle systems are robots or unmanned machines used to safely transport all kinds of products without human intervention within production, logistic, warehouse and distribution environments.

AGVs are used to consistently and predictably transport material to places that may be serviced by fork lift trucks, conveyors, or manual cart transport. They are generally used in warehouses where high volumes of repetitive movements of material is required, but only little or no human decision making skill is applicable to perform the movement. They are very useful in serving processes where there is no change is contact and use of barriers - such as conveyors - are undesirable in AGVs.

Application of the AGV has broadened during the late 20th century. AGVs often follow markers or wires in the floor, or use own vision, or magnets, or lasers for navigation within a limited range of transportation.

Sandpaper - An Overview

Sandpaper or Glasspaper are a type of coated abrasive that consists of sheets of paper or cloth with abrasive material affixed to one face. Nowadays, sand or glass is not used. 

Sandpaper is produced in different sizes and is used to remove unwanted material from surfaces, either to make them smoother (in painting and wood finishing), to remove a layer of material (e.g. old paint), or to make surface rougher (in gluing). 

Types

Backing:  Backing for sandpaper can have clothes (cotton, polyester, and rayon), PET film, and "fibre", or rubber apart from the paper.

Material: Garnet, emery, aluminium oxide, silicon carbide, alumina-zirconia, Chromium(III) oxide, ceramic aluminium oxide can also be used in sandpapers.

Bonds: Different adhesives, such as Hide glue, are used to bond the abrasive to the paper. Waterproof sandpapers use resin bond and a waterproof backing.

Open coat sandpapers have particles that are separated from each other and it is more flexible.

What is an Abrasive Disc?

Abrasive Disc is a disc of abrasive material that rotates in a tool such as a sander. Abrasive discs are used usually for use in stock removal, blending, finishing and polishing applications. 

Abrasive discs use the combination of several minerals, resin systems and backings for better functionality. This combination results in a wide range of products to meet various requirements for use on most wood, metal, composite, gel coat, painted substrates or hard‑to‑grind materials.

The discs are generally manufactured using a composite material with coarse-particle aggregate pressed and attached together using a cementing matrix to give it a solid, circular shape. Depending on the intended usage of the disc, various forms and cross sections are available. 

Abrasive Discs may also be built using a solid steel or aluminium disc with particles bonded to the surface. Most abrasive discs are artificial composites of artificial aggregates, but initially natural composite stones (millstones) were also used.

What is an Abrasive Cleaner?

An Abrasive Cleaner is a type of mechanical cleaner that physically removes dirt, stains and tarnish the surface.  They are made up of particles or physical abraders and use friction to remove the dirt stains etc. Physical abraders include sandpaper, steel wool, scrubbing pads, etc.  Abrasiveness usually depends or coerciveness of the used material.

Depending on the harshness, there are three types of Abrasive Cleaners.

Mild Abrasives such as fine plastic mesh pads, soft brass wool, nylon coated sponges, rotten-stone and whiting are often used to clean pots and pans, interiors of ovens, and drip pans.

Examples of Moderate Abrasive Cleaners are fine pumice and fine steel wool. Steel wool has grades from 0000-super fine, 000-extra fine, 00-very fine, 0-fine, 1-medium, 2-medium coarse and 3-0 coarse.

Strong Abrasives are the strongest among abrasives. Examples include medium and coarse steel wool, metallic mesh cloths and balls, metallic brushes, coarse pumice, and sand/silica etc.