history of fuel injection petrol engines

 Abstract-A carburetor is a part of a SI engine that converts liquid fuel into vapor. This is mixed with a certain amount of air that allows combustion in the engine. Using a carburetor it is difficult to send a uniform air-fuel mixture in each cylinder of a multi-cylinder engine. Ina multi-cylinder engine, when the petrol-air mixture moves from the first cylinder to the last cylinder, the petrol air mixture becomes weakest at the last cylinder because of the different inertia effects of petrol and air. Thus, the central cylinders which are very closed to the carburetor get the richer mixture. Thus the various cylinders receive the air petrol a mixture in varying quantities and richness. This problem is called maldistribution. Moreover, due to improper burning of fuel in a conventional carburetor engine, a substantial amount of fuel is wasted and emerges out through the exhaust and thus gives less efficiency and more exhaust emissions. In modern automotive technology, the system uses an electronic control system to control and monitor essential parameters like mass airflow rate, fuel pressure, engine temperature, engine speed, air-fuel mixture, etc. The mal-distribution problem is also solved by introducing an automatic fuel injection system (Single Point Fuel Injection(SPFI) or Multi-Point Fuel Injection(MPFI)) which not only calculates the desired air-fuel mixture continuously but also provides the same amount of petrol injected at each cylinder ( in case of MPFI). Although most of the cars in India are incorporated with Microprocessor-based Electronic Fuel Injection (EFI) systems which is developed by foreign companies, such a novel system is yet to be developed indigenously with further improvement in performance by controlling more variables using suitable sensors and modifying selection of petrol injection in a particular stroke of a SI engine. Keywords: Carburetor, IC Engine, Stoichiometric Mixture, Equivalence Ratio, Volumetric Efficiency, Compression Ratio, EFI, Sensors, ECU.

1. INTRODUCTION

The internal combustion engine is an engine in which the combustion of a fuel (e.g., petrol or diesel) occurs with an oxidizer (usually air) in a combustion chamber. Modern cars have engines that have four, six, or eight cylinders. In an internal combustion engine the expansion of the high temperature and pressure gases, which are produced by the combustion, directly applies force to the pistons of the engine which are connected to the crankshaft by a connecting rod. The crankshaft translates the up and down movement of the pistons into the rotational motion that moves the car. Most automobile engines today operate using a four-stroke(suction, compression, expansion, and exhaust) cycle. In old automobiles, proper mixing of air and fuel (Petrol) for an Internal Combustion Engine is made by using a device called a carburetor which is attached to the intake manifold of the IC Engine. The carburetor works on Bernoulli's principle: the faster the air moves, the lower is its static pressure, and the higher is It's dynamic pressure. The throttle (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburetor mechanisms that meter the flow of air being pulled into the engine. The speed of this flow, and therefore its pressure determines the amount of fuel drawn into the airstream. Under all engine operating conditions, the carburetor

must:

 Measure the airflow of the engine

 Deliver the correct amount of fuel to keep the fuel/air mixture in the proper range (adjusting for factors such

as temperature)

 Mix the two finely and evenly This job would be simple if air and gasoline (petrol) were ideal fluids; in practice, however, their deviations from ideal behavior due to viscosity, fluid drag, inertia, etc. require a great deal of complexity to compensate for exceptionally high or low engine speeds. A carburetor must provide the proper fuel/air mixture across a wide range of ambient temperatures, atmospheric pressures, engine speeds and loads, and centrifugal forces. As mentioned earlier, using a carburetor it is very difficult to send a uniform air-fuel mixture in each cylinder of a multi-cylinder engine. In a multi-cylinder engine, when the petrol-air mixture moves from the first cylinder to the last cylinder, the petrol air the mixture becomes weakest at the last cylinder because of the different inertia effects of petrol and air. Thus, the central cylinders that are much closed to the carburetor get the richer mixture. Thus the various cylinders receive the air petrol the mixture in varying quantities and richness. This problem is called mal-distribution. Moreover in a conventional carburetor engine a substantial amount of fuel is wasted (due to not burning properly) and emerges out through the exhaust and thus gives less efficiency and more exhaust emissions. Due to the above disadvantage as well as stringent regulations imposed by the Pollution Control Boards of different countries towards the emission of gases, the use of carburetor was being phased out from the early 1980s and electronic fuel injection system has been in use which takes care of all the essential parameters for best power outputs including control of emission of gases. The maldistribution problem is solved by developing a fuel injection system that provides the same amount of petrol injected at each cylinder (in the case of multi-point fuel injection). The evaluation of Catalytic Converters put a further pound on the Carburetor technology as the Catalytic Converters trap the excess residual Oxygen molecules emitted from the combustion chamber resulting in early clogging of the Catalytic Converter. The emission of the excess residual Oxygen molecules was needed to be checked badly and unfortunately, the technology of the Carburetor was inefficient to regulate the Oxygen content from both the intake air and the residual gases. To curb this need for relatively cleaner emissions from the internal combustion engines Fuel Injection System was developed.

2. MECHANICAL FUEL INJECTION SYSTEM

Fuel Injection system as the name suggests is mainly consists of an Injector or a valve with a small nozzle at the extreme end which is responsible to supply the fuel to the combustion chamber with force resulting from the Atomization of the fuel (breaking of the fuel particles into much smaller molecules), this force is generated from the fuel pump which is generally placed inside the fuel tank, the atomized fuel is easier to burn when combined with the radical oxygen molecules of the air intake creating an optimum fuel and air ratio hence resulting into increased fuel efficiency with remarkably cleaner emissions.

2.1 Review on mechanical injection:

One of the first commercial gasoline injection systems was a mechanical system developed by Bosch and introduced in 1952. This system used a normal gasoline fuel pump, to provide fuel to a mechanically driven injection pump, which had separate plungers per injector to deliver a very high injection pressure directly into the combustion chamber. Chevrolet introduced a mechanical fuel injection system, made by General Motors, in 1956 for its 283 V8 engine. This system directed the inducted engine air across a "spoon-shaped" plunger that moved in proportion to the air volume. The plunger connected to the fuel metering system mechanically dispensed fuel to the cylinders via distribution tubes. This system was not a "pulse" or intermittent injection, but rather a constant flow system, metering fuel to all cylinders simultaneously from a central "spider" of injection lines. The fuel meter was used to adjust the amount of flow according to engine speed and load and included a fuel reservoir, which was similar to a carburetor's float chamber. With its own high-pressure fuel pump, the system supplied the necessary pressure for injection. This was a "port" injection where the injectors were located in the intake manifold, very near to the intake

valve. The engine was rated at 315hp (235 kW).

3. ELECTRONIC FUEL INJECTION SYSTEM

Although, during the period from 1960 to the late 1970s many developments were made by foreign companies towards fuel induction by carburetor but failed to comply with the emissions regulations and as such needed further research for improvement and as a result, a more efficient system called An electronic Fuel Injection System (EFI) has been developed. The EFI System consists of the following parts:

3.1 Engine Control Unit (ECU)

Initially, the ECU was made by designing proper electronic circuits using discrete electronic components for the purpose of controlling mainly the air-fuel mixture by controlling the throttle position at the intake manifold, which had its obvious disadvantages like problems during cold start, uncontrolled exhaust gases, etc. But after the advent of microprocessors during the late 1970s, a radical change in electronic design took place. Modern ECU is a small but very efficient microcontroller chip responsible for calculating and monitoring the different activities of the engine with the help of various sensors installed at different parts of a vehicle and a suitable program. On the basis of the information collected from the sensors, the ECU controls the Fuel Injector’s timing to release the fuel. The ECU also regulates the duration of the opening of the injector valve in different cylinders.

 Fig.1: Fuel Injector

The major functions of ECU are as follows:

i) Control of Air/Fuel ratio One specific air/fuel ratio is highly significant in electronic fuel control systems, namely, the stoichiometric mixture. The stoichiometric (i.e., chemically correct) mixture corresponds to an air and fuel combination such that if combustion were perfect all of the hydrogen and carbon in the fuel would be converted by the burning process to H2O and CO2. For gasoline, the stoichiometric mixture ratio is 14.7:1. Stoichiometry is sufficiently important that the fuel and air the mixture is often represented by a ratio called the equivalence ratio, which is given the specific designation λ. The equivalence ratio is defined as follows:

 (actual air/fuel ratio)

λ = -----------------------------------

 (air/fuel ratio at stoichiometry)

A relatively low air/fuel ratio, below 14.7 (corresponding to λ < 1), is called a rich mixture; an air/fuel ratio above 14.7 (corresponding to λ > 1) is called a lean mixture. Emission control is strongly affected by air/fuel ratio, or by λ. For an engine with fuel injection, an engine control unit (ECU) will determine the quantity of fuel to inject based on a number of parameters. If the throttle position sensor is showing the throttle pedal is pressed further down, the Mass airflow sensor will measure the amount of additional air being sucked into the engine and the ECU will inject a fixed quantity of fuel into the engine ( most of the engine fuel inlet quantity is fixed). If The engine coolant temperature sensor is showing the engine has not warmed up yet, more fuel will be injected (causing the engine to run slightly 'rich' until the engine warms up). Mixture control on computer-controlled carburetors works similarly but with a mixture control solenoid or stepper motor incorporated in the float bowl of the carburetor.

ii) Control of ignition timing A spark-ignition engine requires a spark to initiate combustion in the combustion chamber. An ECU can adjust the exact timing of the spark (called ignition timing) to provide better power and economy. If the ECU detects knock, a condition which is potentially destructive to engines, and "judges" it to be the result of the ignition timing being too early in the compression stroke, it will delay (retard) the timing of the spark to prevent this. Since knock tends to occur more easily at lower rpm, the ECU controlling an automatic transmission will often downshift into a lower gear as a first attempt to alleviate knock.

iii) Control of idle speed

Most engine systems have idle speed control built into the ECU. The engine RPM is monitored by the crankshaft position sensor which plays a primary role in the engine timing functions for fuel injection, spark events, and valve timing. Idle speed is controlled by a programmable throttle stop or an idle air bypass control stepper motor. Early carburetor-based systems used a programmable throttle stop using a bidirectional DC motor. Early TBI systems used an idle air control stepper motor. Effective idle speed control must anticipate the engine load at idle. Changes in this idle load may come from HVAC systems, power steering systems, power brake systems, and electrical charging and supply systems. Engine temperature and transmission status and lift and duration of camshaft also may change the engine load and/or the idle speed value desired. A full authority throttle control system may be used to control idle speed, provide cruise control functions, and top speed limitation.

iv) Control of variable valve timing Some engines have Variable Valve Timing. In such an engine, the ECU controls the time in the engine cycle at which the valves open. The valves are usually opened sooner at a higher speed than at a lower speed. This can optimize the flow of air into the cylinder, increasing power and economy.

v) Control of Emission

The exhaust emissions are much cleaner because the more precious and accurate fuel metering reduces the concentration of toxic combustion byproducts like CO, Hydrocarbons, CnHm,\Nitrogen Oxides, Sulphur Oxides, and Smoke, leaving the engine. The emission-quality is further improved by the use of a catalytic Converter. An Oxygen Sensor is attached to the Catalytic Converter and is responsible to monitor the volume of Oxygen in the exhaust, on the basis of the data, sent, the ECUdecides how rich or lean fuel is is and air mixture should be.Moreover, the undesirable exhaust gas emission of NOx was significantly reduced while maintaining a relatively high level of torque by recirculating a precisely controlled amount of exhaust gas into the intake. which is called Exhaust gas recirculation (EGR). The mechanism by which EGR affects NOx production is related to the peak combustion temperature. Roughly, the NOx generation rate increases with increasing peak combustion temperature if all other variables remain fixed. Increasing EGR tends to lower this temperature; therefore, it tends to lower NOx generation.

The system with ECU (Engine Control Unit)

Engine speed

Engine load

Coolant temperature

Air temperature

Fuel rail temperature

Throttle position sensor

EGR sensor

Battery charge

Other system links

 with ECU (Engine Control Unit)

3.2 Types of Electronic Fuel Injectors.

There are two types of injection systems:

i) Port Fuel Injection system (PFI), where the petrol is

injected through the port i.e., at the intake manifold, and

ii) Gasoline Direct Injection (GDI), where the petrol is injected directly into the cylinders at high pressure. Electronic controlled Port Fuel Injection (PFI) systems instead of fuel systems with carburetors have been used since the 1980s. In fuel injection systems, induced air can be metered precisely and the fuel is injected in the manifold to air amount. By using the lambda sensor in the exhaust system, the air/fuel ratio is held at a stable value. It would have been almost impossible to comply with the increasing emissions regulation without electronic fuel control.

3.3 Advantages of Petrol Injection in SI Engine

If the port fuel injection system is compared with the carburetor

system, it can be seen that PFI has some

advantages. These are;

1. Fuel response is practically instantaneous with an increase in airflow. Because of these, there will be fewer emissions.

2. Increased volumetric efficiency and therefore increased output power and torque. The carburetor venturi prevents air and, in turn, volumetric efficiency decreases.

3. Low specific fuel consumption. In the engine with a carburetor, fuel cannot be delivered with the same amount and with the same air/fuel ratio per cycle, for each cylinder.

4. The more rapid engine response to changes in throttle position. This increases the drive comfort.

5. For fewer rotation components in the fuel injection system, the noise decreases.

6. Acceleration becomes faster.

7. Ice formation on the throttle plate is eliminated.

8. Starting is easier. Though the port fuel injection system has some advantages, it cannot meet the existing continuously increasing demands on engine performance, emission regulations, and fuel economy. The electronic controlled gasoline direct injection systems were started to be used instead of port fuel injection systems in the 1990s.

The Gasoline Direct Injection (GDI) engines give a number of features, which could not be realized with port injected engines: avoiding fuel wall film in the manifold, improved accuracy of air/fuel ratio during dynamics, reducing throttling losses of the gas exchange by stratified and homogeneous lean operation, higher thermal efficiency by stratified operation and increased compression ratio, decreasing the fuel consumption and CO2 emissions, lower heat losses, fast heating of the catalyst by injection during the gas expansion phase increased performance and volumetric efficiency due to cooling of air charge, better cold start performance and better the drive comfort. PFI engines work at a stoichiometric air/fuel ratio which restricts the fuel economy. Moreover, the compression ratio is about 9/1-10/1 which cannot be increased further to prevent knock. Whereas,

 ECU

Fuel injectors

Idle control

actuator

Diagnostics

GDI engines operate with the lean mixture and unthrottled at part loads and with homogeneous charge and stoichiometric or slightly rich mixture at full load. The compression ratio is around 12/1 and the overall air/fuel ratio is lean. This certainly gives a better power output.

3.3 Disadvantages of Petrol Injection in SI Engine

1. High Initial Cost/High Replacement Cost.

 2. Increased are and Attention/More Servicing Problems.

 3. Requires Special Servicing Equipment to Diagnose

 Faults and Failures.

 4. Special Knowledge of Mechanical and Electrical

 Systems Needed to Diagnose and Rectify Faults.

5. Injection Equipment Complicated, Delicate to Handle, and Impossible to Service by Roadside Service Units.

 6. Contain More Mechanical and Electrical Components

 Which May Go Wrong.

7. Increased Hydraulic and Mechanical Noise Due to

 Pumping and Metering of Fuel.

8. Very Careful Filtration Needed Due to Fine Tolerances of Metering and Discharging Components.

9. More Electrical/Mechanical Power Needed to Drive  Fuel Pump and/or Injection Devices.

10. More Fuel Pumping/Injection Equipment and Pipe Plumbing Required- Maybe Awkwardly Placed and  Bulky.

3.4 Review on earlier designs on electronic fuel injection

The first commercial electronic fuel injection (EFI) system was Electrojector (which uses discrete electronic components), developed by the Bendix Corporation and was offered by American Motors Corporation (AMC) in 1957. The Electrojector was rated at 288 bhp (214.8 kW). The EFI produced peak torque 500 rpm lower than the equivalent carbureted engine. This EFI system ran fine in warm weather but suffered hard starting in cooler temperatures. Bosch developed an electronic fuel injection system (using discrete electronic components), called D-Jetronic (D for Druck, German for "pressure"), which was first used on the VW 1600TL/E in 1967. This was a speed/density system, using engine speed and intake manifold air density to calculate "air mass" flow rate and thus fuel requirements. Bosch superseded the D-Jetronic system with the K-Jetronic and L-Jetronic systems for 1974, though some cars (such as the Volvo 164) continued using D-Jetronic for the following several years. The Cadillac Seville was introduced in 1975 with an EFI system made by Bendix and modeled very closely on Bosch's Detroit. L-Jetronic first appeared in 1974 which uses a mechanical airflow meter (L for Luft, German for "air") that produces a signal that is proportional to "air volume". This approach required additional sensors to measure the atmospheric pressure and temperature, to ultimately calculate"air mass". L-Jetronic was widely adopted on European cars of that period, and a few Japanese models a short time later. In Japan, the Toyota Celica used electronic, multi-port fuel injection in January 1974. Nissan offered electronic, multi-port fuel injection in 1975 with the Bosch L-Jetronic system. Toyota soon followed with the same technology in 1978. In 1981 saw Mazda offered fuel injection in the Mazda Luce with the Mazda FE engine, and in 1983, Subaru offered fuel injection in the Subaru EA81 engine installed in the Subaru Leone. Honda followed in 1984 with their own system, called PGM-FI in the Honda Accord, and the Honda Vigor using the Honda ES3 engine. The limited-production Chevrolet Cosworth Vega was introduced in March 1975 using a Bendix EFI system with pulse-time manifold injection, four injector valves, an electronic control unit (ECU), five independent sensors, and two fuel pumps. The EFI system was developed to satisfy stringent emission control requirements and market demands for a technologically advanced responsive vehicle. 5000 hand-built Cosworth Vega engines were produced but only 3,508 cars were sold through 1976. In 1980, Motorola introduced the world’s first microprocessor-based electronic engine control unit, the EEC III module. In 1983, the EEC III module was superseded by the EEC IV module. The EEC-IV system has more diagnostic capabilities than previous EEC systems. Its integrated control of engine functions (such as fuel injection and spark timing) has now become the standard approach for electronic fuel injection systems.

4 CONCLUSION

Many researchers and scientists of America, Japan, U.K have done a lot of research work related to electronic petrol injection in SI engines. This technology has been transferred in many automobile vehicles, but in India so far no remarkable research work has been done on the EFI systems in SI engines. This is high time for Indian researchers and scientists to develop a Direct Petrol Injection system (or Gasoline Direct Injection system) in SI engines to have better efficiency and fuel economy engines. Presently, considering cost and efficiency although Port Fuel Injection technique is used in some petrol engines, the fuel economy and emissions of these engines cannot be improved further, as these engines operate with a stoichiometric mixture. Whereas, Gasoline Direct Injection engines have become popular due to their improved power output and emissions that are complying with stringent environmental protection agency standards. The main disadvantage of the GDI engine is that this is very costly. Since this technique has the potentials for the reduction of toxic gases, CO2 emissions as well as there is the scope of improving fuel efficiency, further research work is needed not only for indigenous development but also for further improvement by including other variables e.g., ignition time, rpm limit, coolant temperature correction, fuel pressure modifier, and also modifying the selection of fuel injection point, electronic valve control without using cam etc.

automotive battries information

 Typically, starting uses much less than three percent of the battery potential. For this purpose, automotive batteries are designed to deliver most modern-day for a quick period of time. They are now and again known as "SLI batteries" for this reason, for beginning, lights, and ignition. SLI batteries aren't designed for deep discharging, and a full discharge can reduce the battery's lifespan. As nicely as beginning the engine, an SLI battery substances the extra strength necessary while the vehicle's electrical necessities exceed the delivery from the charging system. It is likewise a stabilizer, nighttime out doubtlessly detrimental voltage spikes.[2] While the engine is strolling maximum of the energy is furnished by means of the alternator, which includes a voltage regulator to maintain the output between 13.Five and 14.5 V.[3] Modern SLI batteries are lead-acid kind, the use of six collection-connected cells to offer a nominal 12-volt machine (in maximum passenger automobiles and light vans), or twelve cells for a 24-volt device in heavy trucks or earth-transferring system, Gas explosions can arise on the negative electrode wherein hydrogen fuel can increase because of blocked battery vents or a poorly ventilated place, mixed with an ignition source. Explosions for the duration of engine start-up are usually associated with corroded or dirty battery posts. A 1993 look at by way of the United States National Highway Traffic Safety Administration said that 31% of automobile battery explosion injuries took place even as charging the battery. The subsequent-most not unusual scenarios had been even as working on cable connections, whilst leap-starting, normally via failing to hook up with the useless battery before the charging source and failing to connect with the automobile chassis in preference to without delay to the grounded battery publish, and whilst checking fluid tiers.[5][6] Close to two-thirds of those injured suffered chemical burns, and almost three-fourths suffered eye injuries, among different possible accidents. Electric and hybrid motors Electric vehicles (EVs) are powered by means of an excessive-voltage electric vehicle battery, however, they usually have an automotive battery as nicely, with the intention to use general car accessories which are designed to run on 12 V. They are often called auxiliary batteries. Unlike traditional, inner combustion-engined cars, EVs do not rate the auxiliary battery with an alternator—rather, they use a DC-to-DC converter to step down the high voltage to the required drift-price voltage (usually around 14 V).

History

Early automobiles did not have batteries, as their electric structures had been confined. A bell was used instead of an electric-powered horn, headlights have been fuel-powered, and the engine became started out with a crank. Car batteries became broadly used around 1920 as vehicles became geared up with electric-powered starter cars. The sealed battery, which did now not require refilling, changed into invented in 1971. The first starting and charging structures had been designed to be 6-volt and high-quality-ground systems, with the vehicle's chassis directly connected to the fantastic battery terminal. Today, nearly all road motors have a bad ground system. The bad battery terminal is hooked up to the auto's chassis. The Hudson Motor Car Company become the first to use a standardized battery in 1918 when they commenced the use of Battery Council International batteries. BCI is the corporation that units the dimensional requirements for batteries. Cars used 6 V electric structures and batteries until the mid-Nineteen Fifties. The changeover from 6 to 12 V passed off whilst larger engines with better compression ratios required more electric power to start. Smaller automobiles, which required less electricity to begin stayed with 6 V longer, for instance, the Volkswagen Beetle inside the mid-1960s and the Citroën 2CV in 1970. In the 1990s a 42V electric device fashionable was proposed. It was supposed to permit greater powerful electrically pushed accessories, and lighter automobile wiring harnesses. The availability of better-efficiency automobiles, new wiring strategies, and digital controls, and a focal point on hybrid automobile structures that use excessive-voltage starter/mills have largely removed the rush for switching the primary automobile voltages. Design A car battery is an instance of a moist cell battery, with six cells. Each mobile of a lead storage battery consists of exchange plates manufactured from a lead alloy grid packed with sponge lead (cathode plates) or lined with lead dioxide (anode).[14] Each cellular is full of a sulfuric acid solution, that is the electrolyte. Initially, cells every had a filler cap, thru which the electrolyte level will be considered and which allowed water to be delivered to the cell. The filler cap had a small vent hollow which allowed hydrogen fuel generated for the duration of charging to escape from the cell.The cells are connected via short heavy straps from the high-quality plates of 1 cell to the terrible plates of the adjoining mobile. A pair of heavy terminals, plated with result in the face up to corrosion, are mounted at the pinnacle, every so often the facet, of the battery. Early vehicle batteries used difficult rubber cases and timber plate separators. Modern gadgets use plastic instances and woven sheets to prevent the plates of mobile from touching and quick-circuiting.In the past, auto batteries required ordinary inspection and protection to update water that becomes decomposed throughout the operation of the battery. "Low-protection" (now and again referred to as "0-upkeep") batteries use a one-of-a-kind alloy for the plate factors, decreasing the quantity of water decomposed on charging. A modern-day battery won't require additional water over its beneficial life; a few types dispose of the man or woman filler caps for each cell. A weak point of these batteries is that they may be very intolerant of deep discharge, together with when the car battery is completely drained by using leaving the lights on. This coats the lead plate electrodes with lead sulfate deposits and might lessen the battery's lifespan by using a 3rd or greater.VRLA batteries, also referred to as absorbed glass mat (AGM) batteries are more tolerant of deep discharge however are greater costly. VRLA batteries do now not allow the addition of water to the cell. The cells each have an automated pressure launch valve, to protect the case from rupture on severe overcharge or internal failure. A VRLA battery can not spill its electrolyte which makes it specifically beneficial in vehicles such as bikes.Batteries are typically made of six galvanic cells in a sequence circuit. Each mobile provides 2.1  volts for a total of 12.6 volts at a full fee.[16] During discharge, at the negative (lead) terminal a chemical response releases electrons to the external circuit, and at the advantageous (lead oxide) terminal another chemical response absorbs electrons from the external circuit. This drives the electrons via the external circuit wire (an electrical conductor) to provide an electric contemporary (electricity). As the battery discharges, the acid of the electrolyte reacts with the substances of the plates, converting their floor to steer sulfate. When the battery is recharged, the chemical response is reversed: the lead sulfate reforms into lead dioxide. With the plates restored to their original situation, the process can be repeated.Some vehicles use different starter batteries. The 2010 Porsche 911 GT3 RS has a lithium-ion battery as an option to store weight.[17] Heavy automobiles might also have batteries in series for a 24 V system or may also have collection-parallel companies of batteries offering 24 V.

Specifications

Physical format batteries are grouped by means of physical length, kind and location of the terminals, and mounting fashion.

Amp-hours (Ah) Ampere hours (Ah or A·h) is a unit associated with the power garage ability of the battery. This score is needed by regulation in Europe. The ampere-hour rating is generally described as the product of (the present-day a battery can offer for 20 hours at a consistent charge, at 80 levels F (26.6 °C), whilst the voltage drops to a reduce-off of 10.Five volts) instances 20 hours. In theory, at eighty levels F, a 100 Ah battery should be capable of constantly provide 5 amps for 20 hours even as maintaining a voltage of at least 10.Five volts. It is important to comprehend that the relationship between the Ah capacity and the discharge fee is not linear; as the discharge rate is elevated, the capability decreases. A battery with a 100Ah rating typically will not be able to preserve a voltage above 10.5 volts for 10 hours while being discharged at a constant price of 10 amps. Capacity also decreases with temperature. Cranking amperages (CCA, CA, MCA, HCA)

Cold-cranking amperes (CCA): the amount of present-day a battery can provide at zero °F (−18 °C) for 30 seconds while preserving a voltage of at least 7.2 volts. Modern motors with pc managed gasoline-injected engines take no a number of seconds to begin and CCA figures are less essential than they were.[19] It is essential not to confuse CCA with CA/MCA or HCA numbers as the latter will continually be higher due to hotter temperatures. For instance, a 250 CCA battery may have extra starting strength than a 250 CA (or MCA) one, and also a 250 CA will have greater than a 250 HCA one.

Cranking amperes (CA): the amount of present-day a battery can provide at 32 °F (0 °C), again for 30 seconds at a voltage same too, or extra than, 7.2 volts.

Marine cranking amperes (MCA): like CA, the quantity of modern a battery can offer at 32 °F (zero °C), and regularly discovered on batteries for boats (consequently "marine") and lawn garden tractors which might be less possibly to be operated in situations wherein ice can shape.

Hot cranking amperes (HCA) is the amount of modern a battery can provide at 80 °F (27 °C). The rating is defined because the modern-day lead-acid battery at that temperature can deliver for 30 seconds and maintain at least 1.2 volts according to cellular (7.2 volts for a 12-volt battery).[citation needed]

Reserve ability minutes (RCM or RC)

A battery's potential to sustain a minimal stated electrical load; its miles is described as the time (in mins) that a lead-acid battery at eighty °F (27 °C) will continuously deliver 25 amperes earlier than its voltage drops below 10.5 volts.[citation needed]

Group size

Battery Council International (BCI) institution length specifies a battery's bodily dimensions, which include length, width, and height. These corporations are decided through the enterprise.

Date codes

In the US there are codes on batteries to help customers purchase a currently produced one. When batteries are saved, they start losing their rate; that is due to non-present day-generating chemical reactions of the electrodes with the battery acid. A battery made in October 2015 may have a numeric code of 10-five or an alphanumeric code of K-five. "A" is for January, "B" is for February, and so forth (the letter "I" is skipped).

In South Africa, the code on a battery to suggest production date is a part of the casing and solid into the bottom left of the quilt. The code is 12 months and week quantity (YYWW), e.G. 1336 is for week 36 in the yr 2013.

Use and protection

Excess warmness is a prime purpose of battery failures, as when the electrolyte evaporates due to excessive temperatures, lowering the powerful floor region of the plates uncovered to the electrolyte, and leading to sulfation. Grid corrosion prices grow with temperature. Also, low temperatures can result in battery failure. If the battery is discharged to the point wherein it can't start the engine, the engine may be jumping began through an outside source of energy. Once jogging, the engine can recharge the battery if the alternator and charging gadget are undamaged. Corrosion at the battery terminals can save you an automobile from the beginning because of electric resistance, which can be averted by means of the right software of dielectric grease.Sulfation is while the electrodes become lined with a tough layer of lead sulfate, which weakens the battery. Sulfation can appear when the battery isn't always fully charged and stays discharged.[30] Sulfated batteries have to be charged slowly to save you harm.

SLI batteries are not designed for deep discharge, and their existence is reduced while subjected to this. Car batteries use of lead-antimony plates requires ordinary topping-up with pure water to update water misplaced because of electrolysis and evaporation. By changing the alloying element to calcium, extra recent designs have decreased the rate of water loss. Modern vehicle batteries have reduced renovation necessities, and won't provide caps for the addition of water to the cells. Such batteries consist of extra electrolytes above the plates to allow for losses for the duration of the battery lifestyle. Some battery producers include an integrated hydrometer to reveal the kingdom of charge of the battery.

A superb (red) jumper cable related to the battery post. A non-obligatory hydrometer window is visible through the unmarried jumper clamp. The black poor jumper clamp isn't shown.

The number one put-on-out mechanism is the dropping of active fabric from the battery plates, which accumulates at the bottom of the cells and which may additionally eventually short-circuit the plates. This may be substantially decreased by enclosing one set of plates in plastic separator bags, crafted from a permeable fabric. This lets in the electrolyte and ions to pass through however continues the sludge building up from bridging the plates. The sludge largely includes lead sulfate, which is produced at each electrode.

Environmental impact

Battery recycling of automotive batteries reduces the need for sources required for the manufacture of recent batteries, diverts toxic lead from landfills, and stops the hazard of unsuitable disposal. Once a lead-acid battery ceases to maintain a rate, its miles are deemed a used lead-acid battery (ULAB), which is classed as unsafe waste underneath the Basel Convention. The 12-volt automobile battery is the maximum recycled product inside the international, according to the United States Environmental Protection Agency. In the U.S. By myself, approximately one hundred million automobile batteries 12 months are replaced, and 99 percent of them grow to become in for recycling.[33] However, recycling may be carried out incorrectly in unregulated environments. As part of an international waste exchange, ULABs are shipped from industrialized international locations to growing nations for disassembly and healing of the contents. About ninety-seven percent of the lead may be recovered. Pure Earth estimates that over 12 million Third World people are affected by lead infection from ULAB processing

Evolution of mobile's

 

Mobile telephones

 mobile cellphone

 is a telephone that may make and re-ceive calls over a radio frequency provider even as the useris transferring inside a cellphone carrier area. The radio fre-quency hyperlink establishes a connection to the switching sys-tems of a cell smartphone operator, which gives accessto the public switched telephone network (PSTN). Mostmodern cell phone services use a cellular networkarchitecture, and therefore mobile telephones are oftenalso referred to as

 mobile telephones 

 or

 mobile telephones 

. In addi-tion to telephony, present day mobile phones help a va-riety of other services, along with text messaging, MMS,e-mail, Internet access, brief-variety wi-fi communica-tions (infrared, Bluetooth), enterprise programs, gam-ing, and photography. Mobile telephones which offer theseand greater trendy computing talents are referred toas smartphones.The first hand-held mobile smartphone was demonstrated byJohn F. Mitchell

and Martin Cooper of Motorolain 1973, the use of a handset weighing c. 4.Four lbs (2 kg).

In 1983, the DynaTAC 8000x become the first commer-cially available hand-held cell phone. From 1983 to2014, international mobile telephone subscriptions grew toover seven billion, penetrating one hundred% of the global pop-ulation and reaching the lowest of the financial pyra-mid.

In2014,thetopmobilephonemanufacturerswereSamsung, Nokia, Apple, and LG.

1 History

Main article: History of cellular phonesA hand held cell radio phone carrier was en-

Martin Cooper  of Motorola made the first publicized hand held mobile cellphone name on a prototype DynaTAC version on April four,1973. This is a reenactment in 2007.

Visioned inside the early levels of radio engineering. In1917, Finnish inventor Eric Tigerstedt filed a patent fora “pocket-length folding cellphone with a very skinny vehicle-bon microphone”. Early predecessors of cell phones1

 2 FEATURES 

protected analog radio communications from ships andtrains. The race to create absolutely portable cellphone de-vices started out after World War II, with developments tak-ingplaceinmanycountries. Theadvancesinmobiletele-phonyhavebeentracedinsuccessive“generations”, start-ing with the early “0G” (zeroth technology) services, suchas Bell System's Mobile Telephone Service and its suc-cessor, the Improved Mobile Telephone Service. These“0G” structures were no longer cell, supported few simultane-ous calls, and had been very pricey.

The Motorola DynaTAC 8000X. First commercially availablehandheld cellular cell cellphone, 1984.

The first hand-held cell cell telephone become demonstratedby Motorola in 1973. The first industrial automatedcellular network became released in Japan by using Nippon Tele-graph and Telephone in 1979. This become accompanied in 1981by the simultaneous release of the Nordic Mobile Tele-cellphone (NMT) machine in Denmark, Finland, Norway andSweden

Several other countries then accompanied in theearly to mid-Eighties. These first-technology (1G) systemscould aid some distance more simultaneous calls, however still usedanalog generation.In 1991, the second-era (2G) digital mobile tech-nology turned into launched in Finland by way of Radiolinja on theGSM preferred. This sparked competition inside the sectoras the new operators challenged the incumbent 1G internet-work operators.Ten years later, in 2001, the 1/3 technology (3G) waslaunched in Japan by using NTT DoCoMo at the WCDMAstanda

This became followed by way of 3.5G, 3G+ or turbo3G improvements primarily based at the excessive-pace packet get admission to(HSPA) circle of relatives, allowing UMTS networks to have higherdata transfer speeds and potential.By 2009, it had become clear that, in some unspecified time in the future,3G networks might be overwhelmed by way of the growthof bandwidth-intensive applications, including streamingmedia.

Consequently, the industry started out searching todata-optimized fourth-generation technologies, with thepromise of pace improvements up to 10-fold over exist-ing3Gtechnologies. Thefirsttwocommerciallyavailabletechnologies billed as 4G were the WiMAX preferred, of-fered in North America through Sprint, and the LTE trendy,first offered in Scandinavia by means of TeliaSonera.

2 Features

Main article: Mobile telephone featuresSee also: SmartphoneAll mobile telephones have a lot of functions in commonplace,however manufacturers are trying to find product differentiation through addingfunctions to attract consumers. This opposition has ledto extraordinary innovation in cell telephone improvement over thepast two decades.The common additives located on all phones are:

•

 A battery, supplying the energy source for the phonefunctions.

•

 An input mechanism to permit the consumer to interactwith the smartphone. The maximum common input mecha-nism is a keypad, but contact screens also are foundin maximum smartphones.

•

 A screen which echoes the person’s typing, displaystext messages, contacts and more.

•

 Basic mobile smartphone offerings to allow customers to makecalls and ship textual content messages.

 

2.Three SIM card 

 three

•

 All GSM telephones use a SIM card to allow an accountto be swapped amongst devices. Some CDMA de-vices actually have a similar card known as a R-UIM.

•

 Individual GSM, WCDMA, iDEN and somesatellite smartphone gadgets are uniquely identified byan International Mobile Equipment Identity (IMEI)quantity.Low-stop cell telephones are regularly referred to as featurephones, and offer basic telephony. Handsets with moreadvanced computing ability thru the use of nativesoftware packages have become called smartphones.Several telephone collection were introduced to addressspecific marketplace segments, such as the RIM BlackBerryfocusing on company/corporate client electronic mail needs,the Sony-Ericsson 'Walkman' collection of music/phones and'Cyber-shot' collection of digicam/telephones, the Nokia Nseriesofmultimediaphones,thePalmPre,theHTCDreamandthe Apple iPhone.

2.1 Sound first-class

In sound first-rate, smartphones and characteristic telephones varylittle. Some audio-first-rate improving capabilities, such asVoice over LTE and HD Voice, have regarded and areoften available on more recent smartphones. Sound qualitycan stay a problem with both, as this depends now not somuch on the telephone itself, as on the exceptional of the networkand, in long distance calls, the bottlenecks/choke pointsmet alongside the way.

As such, for lengthy-distance callseven capabilities including Voice over LTE and HD Voice maynot enhance things. In a few cases smartphones can im-prove audio great even on long-distance calls, by using usinga VoIP cellphone provider, with a person else’s WiFi/internetconnection.

2.2 Text messaging

Main article: SMSThe most normally used facts application on mobilephones is Short Message Service (SMS) textual content messaging.The first SMS message became despatched from a pc to amobile cellphone in 1992 within the UK, at the same time as the first character-to-individual SMS from cellphone to cellphone changed into sent in Finlandin 1993.The first cell news provider, brought thru SMS, waslaunched in Finland in 2000, and sooner or later manyorganizations provided “on-demand” and “immediately” newsservices by SMS.MultimediaMessagingService(MMS)wasintroducedin2001.

2.3 SIM card

Main articles: Subscriber Identity Module andRemovable User Identity ModuleGSM function telephones require a small microchip referred to as

Typical cellular cellphone SIM card 

a Subscriber Identity Module or SIM card, so as tofunction. The SIM card is approximately the scale of asmall postage stamp and is typically positioned underneath thebattery in the rear of the unit. The SIM securely storesthe carrier-subscriber key (IMSI) and the Kᵢ used toidentify and authenticate the person of the cell phone.The SIM card permits users to alternate telephones with the aid of simplyremoving the SIM card from one mobile cellphone andinserting it into any other cell telephone or broadbandtelephony tool, supplied that this is not averted bya SIM lock.The first SIM card become made in 1991 by means of Munich smartcard maker Giesecke & Devrient for the Finnish wirelessnetwork operator Radiolinja.

2.4 Multi-card hybrid phones

A hybrid cellular telephone can keep as much as 4 SIM cards.SIM and R-UIM cards may be mixed collectively to allowboth GSM and CDMA networks to be accessed.From 2010 onwards, such phones have become famous in In-dia and Indonesia and other rising markets

History of motorcycle

 History of Motorcycles

With the discovery of steam engines and bicycles, 19th-century scientists quickly realized that combining of these technologies could notably improve shipping on public roads.

The first wave of motorized bicycles began performing best a few short years after the ultimate of Pierre Michaux's famous bicycle pedal motorcycle and lasted to the mid-1880s. Pierre Michaux’s son Ernest made the first motorcycle in his Paris manufacturing unit by using combining a small steam engine to certainly one of their early “boneshaker” bicycle designs. That product kick-commenced the manufacturing of many other fashions, with numerous different inventors executed comparable feat the usage of diverse sorts of steam engines (Sylvester H. Roper used coal burn furnace in 1868, Louis-Guillaume Perreaux used alcohol burner chamber in 1871, Lucius Copeland connected the steam engine to English “farthing-penny” high wheel bicycle in 1881).

A true revolution in the motorbike era occurred in 1885, whilst two German inventors Gottlieb Daimler and Wilhelm Maybach managed to produce the first bike with a gas inner combustion engine. This machine called “Daimler Reitwagen” (using wagon) is nowadays referred to as a primary instance of current bike that we know and use today. Since its appearance, many other inventors and engineers have started making their very own versions of engine-ready bicycles.

Picture Of Lucius Copeland 1894

Ten years after the best of “Daimler reitwagen”, German producer Hildebrand & Wolfmüller” started out as the primary motorbike mass production manufacturing facility. Their initial commercial enterprise did not control to stay alive for extremely lengthy but new safety functions and growth of famous call for resulted in excellent bike expansion for the duration of first years of the twentieth century. Several important manufacturing companies started making their personal motorcycle designs, most drastically English Royal Enfield, Triumph, American Harley-Davidson, Indian Motorcycle Manufacturing Company, and DKW (which held the record for being the biggest motorcycle manufacturing unit before World War II).

After the Second World War, lower prices, increased engineering upgrades, and higher road networks insured the sizeable achievement of motorcycles all the world over. Motorcycles became one of the primary supplies of transport in Asia (in particular in big towns) and American “motorbike membership” motion (combined with their portrayals in the 50s and 60s films) ignited the imagination of the complete world populace. During the Nineteen Sixties, the dominance of American and English producers commenced fading with the emergence of several Japanese manufacturers - Suzuki, Kawasaki, and the Yamaha. They focused their manufacturing on smaller, less expensive, and more efficient bike designs, which helped them to steady the majority of the world's market.

One of the most famous motorcycle fashions of all time is “Honda Super Cub”, which became bought in over 60 million devices. Their dominance lasted to the Nineties whilst several American and European manufacturers managed to reclaim massive components of the world market (nowadays’s most famous western manufacturers encompass names inclusive of BMW, Ducati, Victory, and Harley-Davidson).

Today, motorcycles represent one of the most less expensive kinds of motorized transport on public roads. Daily over 200 million motorcycles are in use all over the globe (collectively with over 590 million automobiles). Leading nations with the best motorbike use are India (37 million motorcycles/mopeds) and China (34 million bikes/mopeds).

With the invention of steam engines and bicycles, 19th-century scientists quickly realized that combining of these technologies could notably improve shipping on public roads.

The first wave of motorized bicycles started outperforming the handiest few short years after the ultimate of Pierre Michaux's famous bicycle pedal motorbike and lasted to the mid-1880s. Pierre Michaux’s son Ernest made the first motorcycle in his Paris manufacturing facility by combining a small steam engine to one among their early “boneshaker” bicycle designs. That product kick-began the manufacturing of many other models, with several other inventors performed similar feat the use of diverse forms of steam engines (Sylvester H. Roper used coal burn furnace in 1868, Louis-Guillaume Perreaux used alcohol burner chamber in 1871, Lucius Copeland attached a steam engine to English “farthing-penny” excessive wheel bicycle in 1881

The true revolution in the motorbike era took place in 1885 when  German inventors Gottlieb Daimler and Wilhelm Maybach controlled to supply the first motorbike with a gas internal combustion engine. This gadget known as “Daimler Reitwagen” (driving wagon) is today referred to as a primary instance of present-day motorbike that we recognize and use nowadays. Since its look, many different inventors and engineers commenced making their own versions of engine-ready bicycle

Ten years after the most appropriate of “Daimler reitwagen”, German manufacturer Hildebrand & Wolfmüller” started out the primary bike mass production manufacturing unit. Their preliminary business did no longer control to live alive for very lengthy but new protection functions and boom of popular demand ended in awesome motorcycle expansion at some stage in first years of the twentieth century. Several foremost production corporations began making their very own bike designs, most significantly English Royal Enfield, Triumph, American Harley-Davidson, Indian Motorcycle Manufacturing Company, and DKW (which held the record for being the most important motorbike production manufacturing unit before World War II).

After the Second World War, lower charges, accelerated engineering enhancements, and higher street networks insured the big success of bikes all the world over. Motorcycles have become one of the primary supply of delivery in Asia (mainly in large cities) and American “motorcycle membership” motion (combined with their portrayals in the 50s and 60s movies) ignited the creativeness of the whole world populace. During the Nineteen Sixties, the dominance of American and English producers commenced fading with the emergence of several Japanese manufacturers - Suzuki, Kawasaki, and the Yamaha. They centered their manufacturing on smaller, inexpensive, and extra efficient motorcycle designs, which helped them to the stable the majority of the world's marketplace.

One of the maximum popular bike fashions of all time is “Honda Super Cub”, which became sold in over 60 million units. Their dominance lasted until the Nineties when several American and European producers controlled to reclaim big components of a worldwide marketplace (today’s most famous western brands include names together with BMW, Ducati, Victory, and Harley-Davidson).

Today, motorcycles represent one of the most low-priced types of motorized shipping on public roads. Daily over 2 hundred million motorcycles are in use everywhere in the international (collectively with over 590 million motors). Leading nations with the greatest motorcycle use are India (37 million bikes/mopeds) and China (34 million motorcycles/mopeds).

History of air conditioner

 

WE TAKE THE AIR CONDITIONER FOR GRANTED, BUT IMAGINE WHAT LIFE WOULD BE LIKE WITHOUT IT.

Once considered a luxury, this invention is now an essential, allowing us to cool homes, businesses, hospitals, data centers, laboratories and other buildings vital to our economy and daily lives. In fact, air temperature is so important to us that 48 percent of all energy consumption in American homes is a result of cooling and heating, according to the Energy Information Administration.

Like most important breakthroughs, modern commercial and residential air conditioning technology is a result of a series of advancements by scientists and inventors who challenged themselves to come up with creative solutions to problems of the day. Scroll through our interactive timeline above and read on to learn about some of the key milestones in air conditioning history.

THE EVILS OF HIGH TEMPERATURES

In the 1840s, physician and inventor Dr. John Gorrie of Florida proposed the idea of cooling cities to relieve residents of "the evils of high temperatures." Gorrie believed that cooling was the key to avoiding diseases like malaria and making patients more comfortable, but his rudimentary system for cooling hospital rooms required ice to be shipped to Florida from frozen lakes and streams in the northern United States. 

To get around this expensive logistical challenge, Gorrie began experimenting with the concept of artificial cooling. He designed a machine that created ice using a compressor powered by a horse, water, wind-driven sails or steam and was granted a patent for it in 1851. Although Gorrie was unsuccessful at bringing his patented technology to the marketplace -- primarily due to the death of his chief financial backer -- his invention laid the foundation for modern air conditioning and refrigeration. 

WRINKLED PAGES, REVOLUTIONARY SOLUTION

The idea of artificial cooling went stagnant for several years until engineer Willis Carrier took a job that would result in the invention of the first modern electrical air conditioning unit. While working for the Buffalo Forge Company in 1902, Carrier was tasked with solving a humidity problem that was causing magazine pages to wrinkle at Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn.

Through a series of experiments, Carrier designed a system that controlled humidity using cooling coils and secured a patent for his "Apparatus for Treating Air,” which could either humidify (by heating water) or dehumidify (by cooling water) air. As he continued testing and refining his technology, he also devised and patented an automatic control system for regulating the humidity and temperature of air in textile mills.

It wasn't long before Carrier realized that humidity control and air conditioning could benefit many other industries, and he eventually broke off from Buffalo Forge, forming Carrier Engineering Corporation with six other engineers.

PUBLIC BUILDINGS GET COOL

At the St. Louis World's Fair in 1904, organizers used mechanical refrigeration to cool the Missouri State Building. The system used 35,000 cubic feet of air per minute to cool the 1,000-seat auditorium, the rotunda and other rooms within the Missouri State Building. It marked the first time the American public was exposed to the concept of comfort cooling. A big breakthrough in comfort cooling technology came in the 1920s, when Americans flocked to movie theaters to watch Hollywood stars on the silver screen.  

Early cooling systems for public theaters were essentially heating systems modified with refrigeration equipment that distributed cold air through floor vents, resulting in hot, muggy conditions at upper levels and much colder temperatures at lower levels, where patrons sometimes resorted to wrapping their feet with newspapers to stay warm. In 1922, Carrier Engineering Corporation installed the first well-designed cooling system for theaters at Metropolitan Theater in Los Angeles, which pumped cool air through higher vents for better humidity control and comfort throughout the building.

In May 1922 at Rivoli Theater in New York, Carrier publicly debuted a new type of system that used a centrifugal chiller, which had fewer moving parts and compressor stages than existing units. The breakthrough system increased the reliability and lowered the cost of large-scale air conditioners, greatly expanding their use throughout the country.

BRINGING COOLING HOME

Despite advancements in cooling technologies, these systems were too large and expensive for homes. Building off refrigeration technology, Frigidaire introduced a new split-system room cooler to the marketplace in 1929 that was small enough for home use and shaped like a radio cabinet. However, the system was heavy, expensive and required a separate, remotely controlled condensing unit. General Electric's Frank Faust improved on this design, developing a self-contained room cooler, and General Electric ended up producing 32 similar prototypes from 1930 to 1931.

Around this same time, Thomas Midgley, Albert Henne and Robert McNary of General Motors synthesized chlorofluorocarbon (CFC) coolants, which became the world's first non-flammable refrigerating fluids, substantially improving the safety of air conditioners. However, the chemicals would be linked to ozone depletion decades later and were eventually phased out by governments all across the globe after the Montreal Protocol in the 1990s. Hydrofluorocarbons (HFCs), which don't destroy the ozone, gain popularity but are eventually linked to climate change. Recent breakthrough research by the Energy Department's Building Techologies Office and Oak Ridge National Laboratory is resulting in new refrigerants and technologies that are less harmful to the planet. 

Home cooling systems got smaller after H.H. Schultz and J.Q. Sherman filed a patent for an air conditioning unit that could be placed on a window ledge. The units hit the market in 1932 but were not widely purchased due to their high cost.

Engineer Henry Galson went on to develop a more compact, inexpensive version of the window air conditioner and set up production lines for several manufacturers. By 1947, 43,000 of these systems were sold -- and, for the first time, homeowners could enjoy air conditioning without having to make expensive upgrades.

By the late 1960s, most new homes had central air conditioning, and window air conditioners were more affordable than ever, fueling population growth in hot-weather states like Arizona and Florida. Air conditioning is now in nearly 100 million American homes, representing 87 percent of all households, according to the Energy Information Administration.

EFFICIENCY STANDARDS DRIVE IMPROVEMENTS

As air conditioning use soared in the 1970s, the energy crisis hit. In response, lawmakers passed laws to reduce energy consumption across the board, setting the stage for the Energy Department’s Appliance and Equipment Standards Program, which establishes a single federal energy efficiency standard for air conditioner manufacturers rather than a patchwork of state-by-state standards.  

Since 1992, the Energy Department has issued conservation standards for manufacturers of residential central air conditioners and heat pumps. The initial standard is expected to net about $29 billion in energy bill savings from 1993 to 2023. The standard passed in 2006 is anticipated to result in around $70 billion in energy bill savings from 2006 to 2035 and avoid more than 369 million metric tons of carbon dioxide emissions, equivalent to the annual greenhouse gas emissions of about 72 million cars.

The program has already driven huge efficiency improvements in new air conditioning technology that has helped consumers save energy and money. In fact, new air conditioners today use about 50 percent less energy than they did in 1990.

THE FUTURE OF AIR CONDITIONING

In addition to appliance standards, the Energy Department’s Emerging Technologies Program within the Building Technologies Office supports applied research and development that makes air conditioning more efficient and sustainable.

Right now, the program is working on the next big thing in air conditioning: non-vapor compression technology, which doesn't use HFCs that harm the environment, ushering in a new era of cooling. It’s estimated that non-vapor compression technologies could reduce energy consumption by 50 percent.

Learn more about the Energy Department’s efforts to improve the energy efficiency and reduce the environmental impact of air conditioning technologies.

MORE ON AIR CONDITIONING

Check out our Energy Saver 101 infographic to learn how air conditioners work.

Check out our Energy Saver 101 infographic to learn how air conditioners work.

Stay up-to-date on how the Energy Department is working to improve air conditioning technology.

Paul LesterPAUL LESTER

Paul Lester is a Digital Content Specialist in the Office of Public Affairs. Paul was born in Ohio but spent most of his life in Florida, where he worked as news researcher/archivist and online editor for the Orlando Sentinel.

Television

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FULL ARTICLE

Television (TV), the digital shipping of transferring snap shots and sound from a source to a receiver. By extending the senses of imaginative and prescient and listening to beyond the bounds of bodily distance, television has had a extensive have an effect on on society. Conceived within the early 20th century as a likely medium for training and interpersonal conversation, it became by means of mid-century a vibrant broadcast medium, the usage of the model of broadcast radio to deliver information and enjoyment to humans everywhere in the international. Television is now delivered in lots of approaches: “over the air” by terrestrial radio waves (conventional broadcast TV); along coaxial cables (cable TV); meditated off of satellites held in geostationary Earth orbit (direct broadcast satellite, or DBS, TV); streamed through the Internet; and recorded optically on virtual video discs (DVDs) and Blu-ray discs.

Shade tv photograph tube

Colour Television Picture Tube

See all media

Related Topics: Cable tv HDTV V-chip Electronic television device Mechanical television device

The technical requirements for cutting-edge tv, both monochrome (black-and-white) and coloration, had been first set up in the middle of the twentieth century. Improvements had been made constantly for the reason that that point, and tv technology changed substantially within the early twenty first century. Much attention was targeted on growing the picture resolution (high-definition tv [HDTV]) and on converting the size of the tv receiver to reveal extensive-display photographs. In addition, the transmission of digitally encoded tv indicators changed into instituted to offer interactive carrier and to broadcast multiple applications within the channel area previously occupied by way of one software.

Despite this continuous technical evolution, modern tv is excellent understood first through studying the history and standards of monochrome television after which through extending that mastering to color. The emphasis of this newsletter, consequently, is on first principles and important trends—simple understanding this is had to understand and recognize destiny technological tendencies and upgrades.

A. Michael Noll

The improvement of television structures

Mechanical systems

The dream of seeing distant places is as old because the human creativeness. Priests in historical Greece studied the entrails of birds, trying to see in them what the birds had seen after they flew over the horizon. They believed that their gods, sitting in comfort on Mount Olympus, were talented with the capacity to observe human interest all over the global. And the outlet scene of William Shakespeare’s play Henry IV, Part 1 introduces the man or woman Rumour, upon whom the opposite characters depend for information of what is taking place within the a long way corners of England.

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For a long time it remained a dream, after which television got here alongside, starting with an unintentional discovery. In 1872, at the same time as investigating materials to be used within the transatlantic cable, English telegraph worker Joseph May found out that a selenium wire become various in its electric conductivity. Further research showed that the exchange passed off whilst a beam of sunlight fell on the twine, which by means of threat were positioned on a table near the window. Although its significance changed into no longer found out at the time, this happenstance provided the basis for changing mild into an electric powered sign.

In 1880 a French engineer, Maurice LeBlanc, published a piece of writing in the journal La Lumière électrique that shaped the idea of all next television. LeBlanc proposed a scanning mechanism that could take benefit of the retina’s transient but finite retainment of a visual photograph. He envisaged a photoelectric cell that would look upon simplest one element at a time of the picture to be transmitted. Starting on the top left corner of the picture, the cell could continue to the right-hand aspect and then leap returned to the left-hand aspect, handiest one line lower. It could maintain on this manner, transmitting facts on how tons mild changed into seen at each portion, till the entire image was scanned, in a manner just like the eye analyzing a web page of textual content. A receiver could be synchronized with the transmitter, reconstructing the authentic picture line by means of line.

The concept of scanning, which established the possibility of using simplest a unmarried wire or channel for transmission of an entire photograph, became and stays to this day the basis of all television. LeBlanc, however, turned into by no means capable of construct a working gadget. Nor changed into the person who took television to the following level: Paul Nipkow, a German engineer who invented the scanning disk. Nipkow’s 1884 patent for an Elektrisches Telescop changed into based totally on a simple rotating disk perforated with an inward-spiraling sequence of holes. It might be positioned in order that it blocked pondered mild from the problem. As the disk rotated, the outermost hole might circulate across the scene, letting thru light from the primary “line” of the image. The next hole could do the same component barely lower, and so on. One whole revolution of the disk could provide a entire image, or “test,” of the difficulty.

This idea became subsequently utilized by John Logie Baird in Britain (see the photo) and Charles Francis Jenkins in the United States to build the arena’s first a success televisions. The question of priority relies upon on one’s definition of television. In 1922 Jenkins despatched a still image by using radio waves, but the first genuine tv success, the transmission of a live human face, become executed through Baird in 1925. (The phrase television itself had been coined by way of a Frenchman, Constantin Perskyi, on the 1900 Paris Exhibition.)

John Logie Baird with tv transmitter

John Logie Baird with tv transmitter

John Logie Baird status next to his television transmitter of 1925–26. To Baird's left in the case is “Stookie Bill,” a ventriloquist's dummy that changed into scanned by the spinning Nipkow disk with a purpose to produce a image sign.

Courtesy of Malcolm Baird

The efforts of Jenkins and Baird had been commonly greeted with ridicule or apathy. As a ways lower back as 1880 an editorial inside the British magazine Nature had speculated that television changed into possible however no longer profitable: the price of constructing a device might now not be repaid, for there has been no way to make cash out of it. A later article in Scientific American concept there is probably some makes use of for television, but entertainment changed into no longer one of them. Most humans idea the idea became lunacy.

Nevertheless, the work went on and started out to produce results and competitors. In 1927 the American Telephone and Telegraph Company (AT&T) gave a public demonstration of the new technology, and by means of 1928 the General Electric Company (GE) had began everyday television publicizes. GE used a machine designed by using Ernst F.W. Alexanderson that presented “the newbie, supplied with such receivers as he can also design or collect, an opportunity to pick out up the indicators,” which have been typically of smoke growing from a chimney or different such exciting subjects. That equal 12 months Jenkins commenced to sell television kits via mail and installed his own television station, displaying caricature pantomime packages. In 1929 Baird convinced the British Broadcasting Corporation (BBC) to permit him to supply half of-hour suggests at midnight three instances per week. The following years saw the primary “television increase,” with heaps of visitors shopping for or constructing primitive units to look at primitive program

Not all people became entranced. C.P. Scott, editor of the Manchester Guardian, warned: “Television? The phrase is half Greek and half Latin. No exact will come of it.” More important, the entice of a brand new era quickly paled. The pictures, formed of handiest 30 traces repeating about 12 times per second, flickered badly on dim receiver displays just a few inches high. Programs were simple, repetitive, and in the end dull. Nevertheless, even at the same time as the growth collapsed a competing improvement became taking area in the realm of the electron