Classification of Automobiles

An automobile is a vehicle that is capable of propelling itself. Since 17th century, several attempts have been made to design and construct a practically operative automobile. Today, automobiles play crucial role in the social, economic and industrial growth of any country.
After the designing of Internal Combustion Engines, the Automobile industries has seen a tremendous growth.

Classification of Automobiles:
Automobiles can be classified into several types based on many criteria. A brief classification of automobiles is listed below:
1. Based on Purpose :
Passenger vehicles : These vehicles carry passengers. e.g: Buses, Cars, passenger trains.
Goods vehicles: These vehicles carry goods from one place to another place. e.g: Goods lorry, Goods carrier.
Special Purpose : These vehicles include Ambulance, Fire engines, Army Vehicles.
2. Based on Load Capacity: Light duty vehicle : Small motor vehicles. eg: Car, jeep, Scooter, motor cycle
Heavy duty vehicle: large and bulky motor vehicles. e.g: Bus, Truck, Tractor
3. Based on fuel used:
Petrol engine vehicles : Automobiles powered by petrol engine. e.g: scooters, cars, motorcycles.
Diesel engine vehicles : Automobiles powered by diesel engine. e.g: Trucks, Buses, Tractors.
Gas vehicles : Vehicles that use gas turbine as power source. e.g: Turbine powered cars.
Electric vehicles : Automobiles that use electricity as a power source. e.g: Electric cars, electric buses.
Steam Engine vehicles : Automobiles powered by steam engine. e.g: Steamboat, steam locomotive,
steam wagon.
4. Based on Drive of the vehicles:
Left Hand drive : Steering wheel fitted on left hand side.
Right Hand drive : Steering wheel fitted on right hand side.
Fluid drive : Vehicles employing torque converter, fluid fly wheel or hydramatic transmission.
5. Based on number of wheels and axles:
Two wheeler : motor cycles, scooters
Three wheeler : Tempo, auto-rickshaws
Four wheeler : car, Jeep, Bus, truck Six wheeler : Buses and trucks have six tires out of which four are carried on the rear wheels for additional reaction.
Six axle wheeler : Dodge(10 tire) vehicle
6. Based on type of transmission:
Automatic transmission vehicles: Automobiles that are capable of changing gear ratios automatically as they move. e.g: Automatic Transmission Cars.
Manual transmission vehicles: Automobiles whose gear ratios have to be changed manually. Semi-automatic transmission vehicles: Vehicles that facilitate manual gear changing with clutch
pedal.
7. Based on Suspension system used:
Convectional – Leaf Spring
Independent – Coil spring, Torsion bar,
Pneumatic.

Carburetor

A carburetor (American and Canadian spelling), carburator , carburettor, or carburetter ( Commonwealth spelling ) is a device that blends air and fuel for an internal combustion engine. It is sometimes colloquially shortened to carb in North America or carby in Australia. [citation needed]
Etymology
The word carburetor comes from the French carbure meaning " carbide". [1] Carburer means to combine with carbon. In fuel chemistry, the term has the more specific meaning of increasing the carbon (and therefore energy) content of a fluid by mixing it with a volatile hydrocarbon.
History and development
The carburetor was invented by an Italian, Luigi De  Cristoforis, in 1876. [citation needed] A carburetor was developed by Enrico Bernardi at the University of Padua in 1882, for his "Motrice Pia", the first petrol combustion engine (one cylinder, 121.6 cc) prototyped on 5 August 1882.[ citation needed ]
A carburetor was among the early [when? ] patents by Karl Benz as he developed internal combustion engines and their components. [2]
Early carburetors were the surface carburetor type, in which air is charged with fuel by being passed over the surface of gasoline. [3]
The world's first carburetor for the stationary engine was invented by the Hungarian engineers János Csonka and Donát Bánki in 1893.[4][5] Parallel to this, the Austrian automobile pioneer Siegfried Marcus invented the rotating brush carburetor .[citation needed]
Frederick William Lanchester of Birmingham, England, experimented with the wick carburetor in cars. In 1896, Frederick and his brother built the first gasoline-driven car in England: a single cylinder 5 hp (3.7 kW) internal combustion engine with chain drive. Unhappy with the performance and power, they re-built the engine the next year into a two-cylinder horizontally opposed version using his new wick carburetor design.
In 1885, Wilhelm Maybach and Gottlieb Daimler developed a float carburetor for their engine based on the atomizer nozzle.[6]
Carburetors were the usual method of fuel delivery for most US-made gasoline -fueled engines up until the late 1980s, when fuel injection became the preferred method. [7] (This change was dictated more by the requirements of catalytic converters than by any inherent inefficiency of carburation; a catalytic converter requires much more precise control over the fuel / air mixture, to closely control the amount of oxygen in the exhaust gases.) In the U.S. market, the last carbureted cars were:
1990 (General public) : Oldsmobile Custom Cruiser, Buick Estate Wagon, Cadillac Brougham, Honda Prelude (Base Model), Subaru Justy
1991 (Police) : Ford Crown Victoria Police Interceptor with the 5.8 L (351 cu in) engine.
1991 (SUV) : Jeep Grand Wagoneer with the AMC 360 engine.
1993 Mazda B2200 (Light Truck)
1994 (Light truck) : Isuzu[8]
In Australia, some cars continued to use carburetors well into the 1990s; these included the Honda Civic (1993), the Ford Laser (1994), the Mazda 323 and Mitsubishi Magna sedans (1996), the Daihatsu Charade (1997), and the Suzuki Swift (1999). Low-cost commercial vans and 4WDs in Australia continued with carburetors even into the 2000s, the last being the Mitsubishi Express van in 2003. Elsewhere, certain Lada cars used carburetors until 2006.
Many motorcycles still use carburetors for simplicity's sake, since a carburetor does not require an electrical system to function. Carburetors are also still found in small engines and in older or specialized automobiles , such as those designed for stock car racing , though NASCAR 's 2011 Sprint Cup season was the last one with carbureted engines; electronic fuel injection was used beginning with the 2012 race season in Cup. [9]
Principles
The carburetor works on Bernoulli's principle : the faster air moves, the lower its static pressure, and the higher its dynamic pressure. The throttle (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburetor mechanisms which 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.
When carburetors are used in aircraft with piston engines, special designs and features are needed to prevent fuel starvation during inverted flight. Later engines used an early form of fuel injection known as a pressure carburetor . Most production carbureted (as opposed to fuel-injected ) engines have a single carburetor and a matching intake manifold that divides and transports the air fuel mixture to the intake valves, though some engines (like motorcycle engines) use multiple carburetors on split heads. Multiple carburetor engines were also common enhancements for modifying engines in the USA from the 1950s to mid-1960s, as well as during the following decade of high- performance muscle cars fueling different chambers of the engine's intake manifold .
Older engines used updraft carburetors, where the air enters from below the carburetor and exits through the top. This had the advantage of never "flooding" the engine, as any liquid fuel droplets would fall out of the carburetor instead of into the intake manifold ; it also lent itself to use of an oil bath air cleaner, where a pool of oil below a mesh element below the carburetor is sucked up into the mesh and the air is drawn through the oil-covered mesh; this was an effective system in a time when paper air filters did not exist.
Beginning in the late 1930s, downdraft carburetors were the most popular type for automotive use in the United States. In Europe, the sidedraft carburetors replaced downdraft as free space in the engine bay decreased and the use of the SU-type carburetor (and similar units from other manufacturers) increased. Some small propeller-driven aircraft engines still use the updraft carburetor design. The main disadvantage of basing a carburetor's operation on Bernoulli's principle is that, being a fluid dynamic device, the pressure reduction in a venturi tends to be proportional to the square of the intake air speed. The fuel jets are much smaller and limited mainly by viscosity, so that the fuel flow tends to be proportional to the pressure difference. So jets sized for full power tend to starve the engine at lower speed and part throttle. Most commonly   this has been corrected by using multiple jets. In SU and other movable jet carburetors, it was corrected by varying the jet size. For cold starting, a different principle was used in multi-jet carburetors. A flow resisting valve called a choke, similar to the throttle valve, was placed upstream of the main jet to reduce the intake pressure and suck additional fuel out of the jets.
Operation
Fixed- venturi, in which the varying air velocity in the venturi alters the fuel flow; this architecture is employed in most carburetors found on cars.
Variable-venturi , in which the fuel jet opening is varied by the slide (which simultaneously alters air flow). In "constant depression" carburetors, this is done by a vacuum operated piston connected to a tapered needle which slides inside the fuel jet. A simpler version exists, most commonly found on small motorcycles and dirt bikes, where the slide and needle is directly controlled by the throttle position. The most common variable venturi (constant depression) type carburetor is the sidedraft SU carburetor and similar models from Hitachi, Zenith-Stromberg and other makers. The UK location of
the SU and Zenith -Stromberg companies helped these  arburetors rise to a position of domination in the UK car market, though such carburetors were also very widely used on Volvos and other non-UK makes.
Other similar designs have been used on some European and a few Japanese automobiles. These carburetors are also referred to as "constant velocity" or "constant vacuum" carburetors. An interesting variation was Ford's VV (Variable Venturi) carburetor, which was essentially a fixed venturi carburetor with one side of the venturi hinged and movable to give a narrow throat at low rpm
and a wider throat at high rpm. This was designed to provide good mixing and airflow over a range of engine speeds, though the VV carburetor proved problematic in service.
A high performance 4-barrel carburetor. 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 :
Cold start
Hot start
Idling or slow-running
Acceleration
High speed / high power at full throttle
Cruising at part throttle (light load)
In addition, modern carburetors are required to do this while maintaining low rates of exhaust emissions . To function correctly under all these conditions, most carburetors contain a complex set of mechanisms to support several different operating modes, called circuits.
Basics Cross-sectional schematic of a downdraft carburetor
A carburetor basically consists of an open pipe through which the air passes into the inlet manifold of the engine. The pipe is in the form of a venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part. Below the venturi is a butterfly valve called the throttle valve — a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air. This valve controls the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. The throttle is connected, usually through a cable or a mechanical linkage of rods and joints or rarely by pneumatic link , to the accelerator pedal on a car or the equivalent control on other vehicles or equipment.
Fuel is introduced into the air stream through small holes at the narrowest part of the venturi and at other places where pressure will be lowered when not running on full throttle. Fuel flow is adjusted by means of precisely calibrated orifices, referred to as jets , in the fuel path.
Off-idle circuit
As the throttle is opened up slightly from the fully closed position, the throttle plate uncovers additional fuel delivery holes behind the throttle plate where there is a low pressure area created by the throttle plate blocking air flow; these allow more fuel to flow as well as compensating for the reduced vacuum that occurs when the throttle is opened, thus smoothing the transition to metering fuel flow through the regular open throttle circuit.
Main open-throttle circuit
As the throttle is progressively opened, the manifold vacuum is lessened since there is less restriction on the airflow, reducing the flow through the idle and off-idle circuits. This is where the venturi shape of the carburetor throat comes into play, due to Bernoulli's principle (i.e., as the velocity increases, pressure falls). The venturi raises the air velocity, and this high speed and thus low pressure sucks fuel into the airstream through a nozzle or nozzles located in the center of the venturi. Sometimes one or more additional booster venturis are placed coaxially within the primary venturi to increase the effect.
As the throttle is closed, the airflow through the venturi drops until the lowered pressure is insufficient to maintain this fuel flow, and the idle circuit takes over again, as described above.
Bernoulli's principle, which is a function of the velocity of the fluid, is a dominant effect for large openings and large flow rates, but since fluid flow at small scales and low speeds (low Reynolds number ) is dominated by viscosity, Bernoulli's principle is ineffective at idle or slow running and in the very small carburetors of the smallest model engines. Small model engines have flow restrictions ahead of the jets to reduce the pressure enough to suck the fuel into the air flow. Similarly the idle and slow running jets of large carburetors are placed after the throttle valve where the pressure is reduced partly by viscous drag, rather than by Bernoulli's principle. The most common rich mixture
device for starting cold engines was the choke, which works on the same principle.
Power valve
For open throttle operation a richer mixture will produce more power, prevent pre-ignition detonation , and keep the engine cooler. This is usually addressed with a spring- loaded "power valve", which is held shut by engine vacuum. As the throttle opens up, the vacuum decreases and the spring opens the valve to let more fuel into the main circuit. On two-stroke engines , the operation of the power valve is the reverse of normal — it is normally "on" and at a set rpm it is turned "off". It is activated at high rpm to extend the engine's rev range, capitalizing on a two-stroke's tendency to rev higher momentarily when the mixture is lean.

Alternative to employing a power valve, the carburetor may utilize a metering rod or step-up rod system to enrich the fuel mixture under high-demand conditions. Such systems were originated by Carter Carburetor [citation needed] in the 1950s for the primary two venturis of their four barrel carburetors, and step-up rods were widely used on most 1-, 2-, and 4-barrel Carter carburetors through the end of production in the 1980s. The step-up rods are tapered at the bottom end, which extends into the main metering jets. The tops of the rods are connected to a vacuum piston and/or a mechanical linkage which lifts the rods out of the main jets when the throttle is opened (mechanical linkage) and/or when manifold vacuum drops (vacuum piston). When the step-up rod is lowered into the main jet, it restricts the fuel flow. When the step-up rod is raised out of the jet, more fuel can flow through it. In this manner, the amount of fuel delivered is tailored to the transient demands of the engine. Some 4-barrel carburetors use metering rods only on the primary two venturis, but some use them on both primary and secondary circuits, as in the Rochester Quadrajet.
Accelerator pump
Liquid gasoline, being denser than air, is slower than air to react to a force applied to it. When the throttle is rapidly opened, airflow through the carburetor increases immediately, faster than the fuel flow rate can increase. This transient oversupply of air causes a lean mixture, which makes the engine misfire (or "stumble")—an effect opposite what was demanded by opening the throttle. This is remedied by the use of a small piston or diaphragm pump which, when actuated by the throttle linkage, forces a small amount of gasoline through a jet into the carburetor throat. [10] This extra shot of fuel counteracts the transient lean condition on throttle tip-in.
Most accelerator pumps are adjustable for volume and/or duration by some means. Eventually the seals around the moving parts of the pump wear such that pump output is reduced; this reduction of the accelerator pump shot causes stumbling under acceleration until the seals on the pump are renewed. The accelerator pump is also used to prime the engine with fuel prior to a cold start. Excessive priming, like an improperly adjusted choke, can cause flooding . This is when too much fuel and not enough air are present to support combustion. For this reason, most carburetors are equipped with an unloader mechanism: The accelerator is held at wide open throttle while the engine is cranked, the unloader holds the choke open and admits extra air, and eventually the excess fuel is cleared out and the engine starts.
Choke
When the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of fuel and making the engine difficult to start; thus, a richer mixture (more fuel to air) is required to start and run the engine until it warms up. A richer mixture is also easier to ignite.
To provide the extra fuel, a choke is typically used; this is a device that restricts the flow of air at the entrance to the carburetor, before the venturi. With this restriction in place, extra vacuum is developed in the carburetor barrel, which pulls extra fuel through the main metering system to supplement the fuel being pulled from the idle and off-idle circuits. This provides the rich mixture required to sustain operation at low engine temperatures.
In addition, the choke can be connected to a cam (the fast idle cam) or other such device which prevents the throttle plate from closing fully while the choke is in operation. This causes the engine to idle at a higher speed. Fast idle serves as a way to help the engine warm up quickly, and give a more stable idle while cold by increasing airflow throughout the intake system which helps to better atomize the cold fuel.
In many carbureted cars, the choke is controlled by a cable connected to a pull-knob on the dashboard operated by the driver. In some carbureted cars it is automatically controlled by a thermostat employing a bimetallic spring , which is exposed to engine heat, or to an electric heating element. This heat may be transferred to the choke thermostat via simple convection, via engine coolant, or via
air heated by the exhaust. More recent designs use the engine heat only indirectly: A sensor detects engine heat and varies electrical current to a small heating element, which acts upon the bimetallic spring to control its tension, thereby controlling the choke. A choke unloader is a linkage arrangement that forces the choke open against its spring when the vehicle's accelerator is moved to the end of its travel. This provision allows a "flooded" engine to be cleared out so that it will start.
Some carburetors do not have a choke but instead use a mixture enrichment circuit, or enrichment. Typically used on small engines, notably motorcycles, enrichments work by opening a secondary fuel circuit below the throttle valves. This circuit works exactly like the idle circuit, and when engaged it simply supplies extra fuel when the throttle is closed.
Classic British motorcycles, with side-draft slide throttle carburetors, used another type of "cold start device", called a "tickler". This is simply a spring-loaded rod that, when depressed, manually pushes the float down and allows excess fuel to fill the float bowl and flood the intake tract. If the "tickler" is held down too long it also floods the outside of the carburetor and the crankcase below, and is therefore a fire hazard.
Other elements The interactions between each circuit may also be affected by various mechanical or air pressure connections and also by temperature sensitive and electrical components. These are introduced for reasons such as response, fuel efficiency or automobile emissions control . Various air
bleeds (often chosen from a precisely calibrated range, similarly to the jets) allow air into various portions of the fuel passages to enhance fuel delivery and vaporization. Extra refinements may be included in the carburetor/ manifold combination, such as some form of heating to aid fuel vaporization such as an early fuel evaporator .
Fuel supply
Float chamber
Holley "Visi-Flo" model #1904 carburetors from the 1950s, factory equipped with transparent glass bowls. To ensure a ready mixture, the carburetor has a "float chamber" (or "bowl") that contains a quantity of fuel at near-atmospheric pressure, ready for use. This reservoir is constantly replenished with fuel supplied by a fuel pump . The correct fuel level in the bowl is maintained by means of a float controlling an inlet valve , in a manner very similar to that employed in a cistern (e.g. a toilet tank).
As fuel is used up, the float drops, opening the inlet valve and admitting fuel. As the fuel level rises, the float rises and closes the inlet valve. The level of fuel maintained in the float bowl can usually be adjusted, whether by a setscrew or by something crude such as bending the arm to which the float is connected. This is usually a critical adjustment, and the proper adjustment is indicated by lines inscribed into a window on the float bowl, or a measurement of how far the float hangs below the top of the carburetor when disassembled, or similar.
Floats can be made of different materials, such as sheet brass soldered into a hollow shape, or of plastic; hollow floats can spring small leaks and plastic floats can eventually become porous and lose their flotation; in either case the float will fail to float, fuel level will be too high, and the engine will not run unless the float is replaced. The valve itself becomes worn on its sides by its motion in its "seat" and will eventually try to close at an angle, and thus fails to shut off the fuel completely; again, this will cause excessive fuel flow and poor engine operation.
Conversely, as the fuel evaporates from the float bowl, it leaves  sediment, residue, and varnishes behind, which clog the passages and can interfere with the float operation. This is particularly a problem in automobiles operated for only part of the year and left to stand with full float chambers for months at a time; commercial fuel stabilizer additives are available that reduce this problem.
The fuel stored in the chamber (bowl) can be a problem in hot climates. If the engine is shut off while hot, the temperature of the fuel will increase, sometimes boiling ("percolation"). This can result in flooding and difficult or impossible restarts while the engine is still warm, a phenomenon known as "heat soak". Heat deflectors and insulating gaskets attempt to minimize this effect. The Carter Thermo-Quad carburetor has float chambers manufactured of insulating plastic (phenolic), said to keep the fuel twenty degrees (F.) cooler.
Usually, special vent tubes allow atmospheric pressure to be maintained in the float chamber as the fuel level changes; these tubes usually extend into the carburetor  throat. Placement of these vent tubes is critical to prevent fuel from sloshing out of them into the carburetor, and sometimes they are modified with longer tubing. Note that this leaves the fuel at atmospheric pressure, and therefore it cannot travel into a throat which has been pressurized by a supercharger mounted upstream; in such cases, the  entire carburetor must be contained in an airtight pressurized box to operate. This is not necessary in  installations where the carburetor is mounted upstream of the supercharger, which is for this reason the more frequent system. However, this results in the supercharger being filled with compressed fuel/air mixture, with a strong tendency to explode should the engine backfire ; this type of explosion is frequently seen in drag races, which for safety reasons now incorporate pressure releasing blow-off plates on the intake manifold, breakaway bolts holding the supercharger to the manifold, and shrapnel-catching ballistic nylon blankets surrounding the superchargers.
Diaphragm chamber
If the engine must be operated in any orientation (for example a chain saw ), a float chamber is not suitable. Instead, a diaphragm chamber is used. A flexible diaphragm forms one side of the fuel chamber and is arranged so that as fuel is drawn out into the engine, the diaphragm is forced inward by ambient air pressure. The diaphragm is connected to the needle valve and as it moves inward it opens the needle valve to admit more fuel, thus replenishing the fuel as it is consumed. As fuel is
replenished the diaphragm moves out due to fuel pressure and a small spring, closing the needle valve. A balanced state is reached which creates a steady fuel reservoir level, which remains constant in any orientation.

The Pros And Cons OfTurbochargers Vs Superchargers

Have you ever wondered what the advantages of a turbocharger are over a supercharger? Or vice versa? Well, wonder no more, because here is the best explanation you're likely to ever read...

When designing an engine to pull in more than atmospheric pressure, tuners often turn to forced induction. It’s one of the fastest ways to add significant power to almost any engine, and there are two prevalent ways it can be done:
supercharging and turbocharging.

What’s the difference?

A supercharger is an air compressor driven by the crankshaft of an engine, usually connected with a belt. Alternatively, a turbocharger is simply an air compressor driven by an exhaust gas turbine. That’s the one key difference; a supercharger requires engine power to run, while a turbocharger runs off waste energy created by the engine. You might assume that because the turbo is run off waste gases that it’s more efficient, and you’d be correct!

1. Turbocharger advantages and disadvantages:

Pros:

Significant increase in horsepower.

Power vs size: allows for smaller engine displacements to produce much more power. relative to their size.

Better fuel economy: smaller engines use less fuel to idle, and have less rotational and reciprocating mass, which improves fuel economy.

Higher efficiency: turbochargers run off energy that is typically lost in naturally-aspirated and supercharged engines (exhaust gases), thus the recovery of this energy improves the overall efficiency of the engine.

Cons:

Turbo lag: turbochargers, especially large turbochargers, take time to spool up and provide useful boost.

Boost threshold: for traditional turbochargers, they are often sized for a certain RPM range where the exhaust gas flow is adequate to provide additional boost for the engine. They typically do not operate across as wide an RPM range as superchargers.

Power surge: in some turbocharger applications, especially with larger turbos, reaching the boost threshold can provide an almost instantaneous surge in power, which could compromise tyre traction or cause some instability of the car.

Oil requirement: turbochargers get very hot and often tap into the engine’s oil supply. This calls for additional plumbing, and is more demanding on the engine oil. Superchargers typically don't require engine oil lubrication.

2. Supercharger advantages and disadvantages:

Pros:

Increased horsepower: adding a supercharger to any engine is a quick solution to boosting power.

No lag: the supercharger’s biggest advantage over a turbocharger is that it does not have any lag. Power delivery is immediate because the
supercharger is driven by the engine’s crankshaft.

Low RPM boost: good power at low RPM in comparison with turbochargers.

Price: cost effective way of increasing
horsepower.

Cons:

Less efficient: the biggest disadvantage of superchargers is that they suck engine power simply to produce engine power. They’re run off an engine belt connected to the crankshaft, so you’re essentially powering an air pump with another air pump. Because of this, superchargers are significantly less efficient than turbochargers.

Reliability: with all forced induction systems (including turbochargers), the engine internals will be exposed to higher pressures and temperatures, which will of course affect the longevity of the engine.

It’s best to build the engine from the bottom up to handle these pressures, rather than relying on stock internals. Superchargers often go hand in hand with big V8s, and they’re certainly capable of producing big power.

Which do I prefer?

As an engineer, it’s difficult to not side with efficiency. Turbochargers simply make more sense, as they improve the efficiency of the engine in multiple ways. Superchargers are an extra demand on the engine, even if they are capable of producing useful boost at low RPM. But if you find yourself unable to decide, it is possible to use both simultaneously, and it’s called twin-charging.

Engineering Explained: The Pros And Cons Of Different Engine Types

Engineering Explained: The Pros And Cons Of Different Engine Types

The most common engine types - the four-cylinder, the boxer-four, straight-six, V6 and V8 - have their
own pros and cons. Here's everything you need to know in one handy guide...

By Engineering

What makes more power, a 4.0-litre V6 engine or a 4.0-litre V8? The answer isn’t so simple. When discussing various engines, the layout isn’t the biggest contributing factor to how much power it makes. With a bit of ingenuity (and you know, cash), a four cylinder engine can make just as much power as a V12. So what makes manufacturers
choose different engine layouts?

Here are the advantages and disadvantages of each layout.

1. Four-cylinder inline four

Let’s start with one of the most common engines, the inline four cylinder. There’s a reason it’s common, largely because it’s so simple: one cylinder bank, one cylinder head and one valve train. Here’s all you need to know:

Advantages:

->The four-cylinder, inline four is small and compact, meaning it easily fits in nearly any engine bay.

-> It’s also lightweight, and with only one exhaust manifold, weight is further reduced.

-> With only one cylinder head, there are fewer moving parts than engines with multiple cylinder banks. This means less energy is lost which
reduces the probability of malfunctions.

-> Primary forces are balanced because the outside two pistons move in the opposite direction of the inside two pistons (see picture above).

-> Four-cylinder engines are easy to work on; the cylinder head is the highest point which makes spark plug jobs and valve train access very
easy.

->. Four-cylinder engines require lower manufacturing costs.

Disadvantages:

-> Secondary forces are not balanced, which ultimately limits the size of the engine.

-> Inline fours will rarely exceed 2.5 litres to 3.0 litres.

-> Larger four cylinder engines will often require balancing shafts to cancel the vibration caused by the secondary imbalance.

->High centre of gravity compared to some layouts (H4).

-> Not as rigid as some layouts (V6, V8).

2. Horizontally-opposed

From a performance standpoint, there aren’t many options as attractive as an engine with horizontally- opposed cylinders. The boxer four isn’t nearly as common as the other engines on this list, but from an engineering standpoint it’s a logical choice for your race car.

Advantages:

Primary and secondary forces are well balanced.

This is a smooth engine.

This allows for less weight on the crankshaft, resulting in less power lost to rotational inertia.

Low centre of gravity allows for better handling.

Disadvantages:

Packaging size: these are very wide engines.

Flat engines were once used in Formula 1 for their performance advantages, but due to their width they obstructed airflow and are no longer used.

Complexity - two cylinder heads/valve trains.

Rocking couple (plane imbalances) due to offset pistons to allow for the connecting rods to connect with the crankshaft.

Maintenance can be challenging if packaging is tight.

3. Straight-six

An engineer’s object of affection, the straight-six is the result of tacking on two more cylinders to an inline four engine. BMW loves them, and it’s the
layout of one of the most well-known boost-ready engines, the 2JZ. So what’s so special about the straight-six?

Advantages:

The straight-six is Inherently balanced.

The layout combined with its firing order leads to essentially the smoothest engine out there.

V12s and Flat-12s are the next step in further reducing vibration, as they are two I6s matched together.

Lower manufacturing cost - single cylinder block with all the cylinders in one orientation.

Simple design, easy to work on much like the I4.

Disadvantages:

Packaging can be difficult due to the length.

Not ideal for FWD vehicles.

High center of gravity (vs flat engines).

Lower rigidity than V engines as it’s long and narrow.

4. V6

Now cut that straight-six in half and match the two cylinder banks to a common crank. The V6 is a common layout when there are six spark plugs
involved. It’s also the current layout for Formula 1 engines. Why use it?

Advantages:

They’re compact and can easily be used for both FWD and RWD vehicles.

Allows for greater displacement than four- cylinder engines, typically meaning more power.

Rigid design. Formula 1 chose to use V6s rather than I4s for the 2014 season because they wanted to use the engine as a stressed member of the car.

Disadvantages:

Two cylinder heads means added cost, complexity, and weight.

Additional rotational inertia and friction (more moving parts).

High centre of gravity vs flat engines.
Cost is often greater than inline.

Secondary imbalance requires additional weight on the crankshaft.

Two exhaust manifolds means additional weight.

5. V8

When you add a cylinder to each bank of the V6, you get an icon in both American muscle and European exotics - the V8. It can produce a refined whine, or a shuddering burble. So what makes this layout such a popular choice?

Advantages:

Packaging size (short in length).

Good balance, depending on the crankshaft type and firing order (flatplane vs crossplane).

Rigid design.
Allows for high displacement.

Disadvantages:

Like a V6, the V8 engine’s weight can be high.

Additional rotational inertia and friction (more moving parts).

Cost and complexity will be higher.

Higher centre of gravity vs flat engines.

Engine weight is usually increased.
Packaging is large, typically restricted to RWD/ AWD vehicles.

Let us know below which engine type you are currently running and what you like and loathe about it.

Supercharger:-

SUPERCHARGER

A supercharger is an air compressor that increases the pressure or density of air supplied to an internal combustion engine.  This gives each intake cycle of the engine more oxygen, letting it burn more fuel and do more work, thus increasing power.

Power for the supercharger can be provided mechanically by means of a belt, gear, shaft, or chain connected to the engine's crankshaft. When power is provided by a turbine powered by exhaust gas, a supercharger is known as a turbo supercharger typically referred to simply as a turbocharger or just
turbo.

Gas Power Cycle

Introduction:

An important application of thermodynamics is the analysis of power cycles through which the  energy absorbed as heat can be continuously converted into mechanical work. A thermodynamic analysis of the heat engine cycles provides valuable information regarding the design of new cycles  or for improving the existing cycles.

Classification of Cycles:

The purpose of a thermodynamic cycle is either to produce power, or to produce refrigeration/pumping of heat. Therefore, the cycles are broadly classified as follows:

(a) Heat engine or power cycles.

(b) Refrigeration/heat pump cycles.

Any thermodynamic cycle is essentially a closed cycle in which, the working substance undergoes a series of processes and is always brought back to the initial state. However, some of the power cycles operate on open cycle. It means that the working substance is taken into the unit from the atmosphere at one end and is discharged into the atmosphere after undergoing a series of processes at the other end. The following are illustrations of heat engines operating on open cycle:

(i) Petrol and diesel engines in which the air and fuel are taken into the engine from a fuel tank and products of combustion are exhausted into the atmosphere.
(ii) Steam locomotives in which the water is taken in the boiler from a tank and steam is exhausted into the atmosphere. Essentially, such devices do not form a cycle. However, they can be analyzed by adding an imaginary processes to bring the state of the working substance, thus completing a cyclic.

Note that the terms closed cycle and open cycle used here do not mean closed system cycle and open system cycle. In fact, the processes both in closed and open cycles could either be closed or open system processes.

Different types of working fluids are employed in the power plants. The nature of the working fluids can be classified into two groups: vapours and gases.
The power cycles are accordingly classified into two groups as:

(1) Vapour power cycles in which the working fluid undergoes a phase change during the cyclic process.
(2) Gas power cycles in which the working fluid does not undergo any phase change.

In the thermodynamic analysis of power cycles, our chief interest lies in estimating the energy conversion efficiency or the thermal efficiency. The thermal efficiency of a heat engine is defined as the ratio of the network delivered to the energy absorbed as heat.

Analysis of Cycles:

In air standard analysis, air is considered as the working medium. The analysis is carried out with the following assumptions.

Assumptions:

(i) The working substance consists of a fixed mass of air and behaves as a perfect gas. The closed system is considered which under goes a cycle process. Therefore, there are no intake or exhaust process.
(ii) The combustion process is replaced by an equivalent heat addition process form an external source. Thus there is no change in the chemical equilibrium of the working fluid and also composition.
(iii) There is no exhaust process; this is replaced by an equivalent heat rejection process.
(iv) Compression and expansion processes in the cycle are considered as reversible adiabatic process.
(v) The specific heats Cp and Cv of air do not vary with temperature.

Definition of Biodiesel

Definition of Biodiesel

Bio-diesel is a vegetable oil processed to resemble Diesel Fuel. The first use of peanut oil was made in 1895 by Dr. Rudolf Diesel himself (1858-1913), who predicted- "The use of vegetable oils engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time." Bio-diesel is the ethyl or methyl ester of fatty acid. Bio-diesel is made from virgin or used vegetable oils (both edible and non-edible) and animal fats through trans-desertification. Just like diesel, bio-diesel operates in compression ignition engines, which essentially require very little or no engine modifications up to require very little or no engine modifications up to 20% blends, and minor modifications for higher percentage blends because bio-diesel is similar to diesel but is very Eco-friendly.

The Recent depletion and fluctuation in prices due to uncertain supplies for fossil fuel, make us to search renewable, safe and non-polluting sources of energy. India is not self sufficient in petroleum and has to import about two third of its requirements. Presently Indian Government spend Rupees 90,000 crores for petroleum fuel and annual consumption is around 40 millions tons. One of the solutions to the current oil crisis and toward off any future energy and economic crunch is to explore the feasibility of substitution of diesel with an alternative fuel which can be produced in our country on a massive scale to commercial utilization.

Indian Government, research institution and automobile industries are taking interest on bio-diesel from various non-edible oil bearing trees like Jatropha, Karanji, Mahua & Neem. As India is short of edible oils even for human consumption and since the cost of edible oil is also very high, it is preferable to use non-edible oils. Jatropha curcas is one of the prospective bio-diesel yielding crops. This paper highlights our work on alternate fuels and the importance of choosing jatropha. It reduces pollution drastically in terms of sulphates and carbon mono-oxide. To start with, we reduced the viscosity problem faced to a large extent by carrying out the transmogrification process in our chemistry laboratory. we also studied the cost factor involved in the usage of jatropha. Performance test was conducted on an electrical loaded diesel engine and a study on the emissions was made using Exhaust Gas Analyzer in our thermal laboratory. The pollution levels came down drastically and performance was better with various blends of jatropha and diesel.

Process Explanation

If methanol is used in the above reaction, it is termed methanolysis and fatty acid methyl esters are generated, which are called biodiesel. Three consecutive and reversible reactions are believed to occur in the transesterification which are given below:

Triglyceride + ROH Catalyst Diglyceride + R' COOR

Diglyceride + ROH Catalyst Monoglyceride + R" COOR

Monoglyceride +ROH Catalyst Glycerol + R"' COOR

The first step is the conversion of triglycerides to diglycerides, followed by the conversion of diglycerides to monoglycerides, and finally monoglycerides to glycerol, yielding one methyl ester molecule from each glyceride at each step. When methanol is used in the esterification A catalyst and excess alcohol are used to increase rate of reaction and to shift the equilibrium to the product side, respectively .

Abstract of Next Generation 2-Stroke Engine

Abstract of Next Generation 2-Stroke Engine

Developed by Orbital leading international developer of engine technologies direct in cylinder fuel injection & lean bum system for enhanced fuel economy & lower emission. This technology exceeds the EP A 2006 emission standards & offers 40% fuel efficiency over conventional two stroke. Different automotive companies have licensed & experimented with Orbital clean burning two-stroke engine & auto major like Peugot, Aprila & other are directly installing these on their new models. It may not take long before this technology reaches India as Bajaj auto already has a tie-up with Orbital. This technology is not only restricted to two wheeler but Ford, BMW and other four wheeler auto majors have used this technology to manufacture cars powered with ASDI. Two stroke engine which much better performance than an equivalent four stroke engine.

Principle Of (A R C) : -

When fuel is brought to the right pressure & temperature; molecule breaks down into what are known as active radical molecules. These are highly unstable chemical compounds. Formed as an intermediate step in the actual combustion reaction. When hot exhaust gases remains in the cylinder the small percentage of active radical molecules combines with the incoming fuel charge & begins to auto ignite at a lower temperature than a pure petrol/air mixture.

1. Fresh fuel (white) enters the combustion chamber, pushing the exhaust (gray) out the open exhaust valve in opposite side of the cylinder.

2. The incoming fuel mixes with the exhaust & some pockets of fuel are isolated within the exhaust. The exhaust valve closes & the compression of the mixture is increased as the piston travels upwards.

3. The fuel/exhaust mixture is compressed & auto ignites as the piston reaches the top· of its stroke. This bums all the fuel, and reduces the emission of unbent hydrocarbons into the environment. At small throttle openings, a conventional two stroke will start a repeating pattern of misfiring, which allows a large amount of unbent gas and oil to be expelled directly into the atmosphere. At these low engine speed, the mixture not ignite by the spark is the expelled directly into the exhaust system. Each time this misfiring occurs, the amount of fuel remaining in the cylinder increase, until it is great enough to be ignited by the spark. But the EXP-2 ignites the entire mixture without the use of spark at low & medium loads and is able to bum off and oil in the cylinder in every cycle, eliminating the possibility of misfire and reducing hydrocarbon emissions. This 400-cc single cylinder not only uses the ASDI and active radial combustion but a trapping valve too. This is a new technology ion the design of exhaust valve for two-stroke engine

Definition of Cylinder deactivation

Definition of Cylinder deactivation

With alternatives to petrol engine being announced ever so often, we could be forgiven for thinking that the old favorite, the petrol engine, is on its last legs. But nothing could be further from the truth and the possibilities for developing the petrol engine are endless.

One of the most crucial jobs on the agenda is to find ways of reducing fuel consumptions, cutting emissions of the green house gas, co2, and also the toxic emissions which threaten air quality. One such fast emerging technology is cylinder deactivation.

CYLINDER DEACTIVATION

2.1 CONSIDERING DAIMLER CHRYSLER

By considering Daimler Chrysler's new 300cc car's powered by a revival of one of the greatest muscle car engine of all time, the V8 Hemi. This third generation grand master of funk has a capacity of 5.7litres snorts out 340 bhp with 54kgm torque and like all Hemis since the early 1950's has a pushrod valve train rather than a over head cam setup. But even though this Hemi can match its forebears on power 'its thirst for fuel has been cut by 10 to 20%. It is done by Chrysler's new multi displacement system (mds).

When using a lot of power, such as during acceleration, the hemi fires on all eight cylinders as usual. But around town or when cruising -even at motor way speeds or under gentle acceleration-the engine switches to frugal four cylinder mode.

Multi displacement system (mds) is activated at part throttle between 1000 rpm and 3000 rpm, when a hydraulically actuated catch in the special valve lifters trips to prevent the valves from opening. Hot gases are trapped in four of the eight cylinders, compressing and expanding like giant air springs as the engine turns over and keeping the cylinder warm. But as long as the valves remain closed, only four cylinders consume fuel instead of eight.

Engine efficiency is also improved because the four dormant cylinders are no longer working hard at sucking air into the engine, something that consumes a substantial amount of power. Although the average fuel saving is 10% ,under certain conditions it is a huge 20%.The transition from eight cylinders to four cylinders happens in just 40 mille seconds under the control of sophisticated engine management software which controls not just the multidisplacement system but also a drive-by-wire throttle.

CONSIDERING HONDA

IN Japan the 3.0 liter I-VTEC (intelligent VTEC) V6 of the Honda inspire can also deactivate tree of its first cylinders refinement being guaranteed by active hydraulic engine mounts to cancel out any vibration and active noise control with in the cabin to neutralize any unwanted booming. Honda's CIVIC IMA hybrid also make use of V TEC to deactivate three cylinders on the over run-again to reduce the pumping losses and cut fuel consumption

CONSIDERING GENERAL MOTORS

The actual idea of cylinder deactivation is not new. General Motors tried it in 1981 with the V-8-6-4 engine but through lack of sophisticated electronics drivability was awful. Now GM is returning to the idea again and is to soon launch Displacement on Demand (DOD} on itsVortecV 8's improving consumption by between 6 and 8%.