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Carnot Cycle

The Carnot cycle is an ideal reversible cyclic process involving the expansion and compression of an ideal gas, which enables us to evaluate the efficiency of an engine utilizing this cycle.

Each of the four distinct processes are reversible.  Using the fact that no heat enters or leaves in adiabatic processes we can show that the work done in one cycle, W = Q1 - Q3 where Q1 is the heat entering at temperature TH  in the isothermal process A -> B and  Q3 is the heat leaving at temperature TC in the isothermal process C -> D.

Remember, this is the ideal heat engine (reversible) efficiency.  It sets the maximum theoretically attainable efficiency of any real engine operating between the same two temperatures.
Be careful.  The temperatures in the ideal gas law must be in Kelvin, therefore the temperatures in the efficiency equation are also in Kelvin.

Car Dashboard Symbols

Have you ever wondered what the lights on your vehicle’s dashboard mean? Some are obvious, but others might have you flipping through the pages of your owner’s manual. To make things easier, we scoured the net to find this handy guide.

Dashboard lights commonly inform drivers about problems like poor battery condition, low oil pressure and high engine temperature. But many cars now have lights for service interval indicators and seatbelt reminders along with malfunctions ranging from faulty anti-skid stability control to blocked air and fuel filters, defective diesel filters or fuel contaminated by water.

Tire Codes

Have you ever wondered what the meaning of numerous codes written on the sidewall of tires could be?
These codes are meant to help you  buy the right tire. And also save your life!
Do you  know that those codes contain information about the type of vehicle to be used with it, Car tire expiration date, size of rim, load and speed ratings? Using a wrong tire can cause fatal accident. Now these codes can really save your life.
Usually, a tire will have similar to P205/60R16 90H printed on its sidewall.

Tire Type
Tire Type The letter "P" at the beginning of the "Tire Size" tells us that the tire is a P-Metric tire, referring to tires made to certain standards within the United States, intended for Passenger vehicles.

If a tire size has no letters at the beginning, this indicates a Euro metric tire. Also note that P-Metric and Euro-Metric tires may have different load capacities.

The letters "LT," either at the beginning or at the end of the tire size indicate the tire was designed for light trucks. Vehicle manufacturers equip some light trucks with "LT" type tires. These tires generally require higher inflation pressures than passenger tires.

T on the other hand means Truck vehicles.

Differential System

Differential is an integral part of all four wheels. A differential is used to allow the wheels to spin at different speeds This is necessary when the vehicle turns .

Differential function :-

Transmits the power to the wheels Changes the direction of rotation by 90ยบ Acts as the final gear reduction in the vehicle, slowing the rotational speed of the transmission one final time before it hits the wheels Splits the engine torque two ways, allowing each output to spin at a different speed

Differential parts and it's function :-

Pinion drive gear :- transfer power from the drive shaft to the ring gear.
Ring gear :- will transfer power to differential case assembly. 
Spider gears :- The spider gear lies at the heart of the differential and special mention should be made about its rotation. 
Differential case assembly :- Hold the gear and drive the axel.  
Rear drive axel :- Transfer torque from differential assembly to the drive wheels.

How Differential works ?!!

When a car is driving straight, the input pinion is turning the ring gear and pinions, and none of the pinions within the cage are rotating -- both side gears are effectively locked to the cage, so rotate at same speed When a car makes a turn, the inside wheel starts giving more resistance, while pinion gears applying equal torque The unequal loads from the tyres cause the pinion gears to rotate and walk around the slower running side wheel. This increases the speed of the outside wheel by the same amount.

Differential advantages and dis advantages :-

*Advantages :-
1- Transfers power from drive shaft to the wheels. 
2- Provides final gear reduction.
3- Splits amount of torque going to each wheel. 
4- Allow the wheels to rotate at different speeds in turns.

*Disadvantages :-
1Increase the rate of tire wear.
2- Lack of safety in the course of the vehicle. 
3- Loss part of the engine's ability.

Types of Differential :-

1- Open Differential

Limitation of Open Differential :-
 If one wheel begins to slip while the other maintains traction, the slipping wheel will receive most of the power This means that if one wheel is spinning on ice while the other is still in contact with the pavement, the OD only cause the slipping wheel to spin faster and very little power will reach the wheel with good traction Similarly, if one wheel is lifted off the ground, nearly all the power will go to the wheel that is off the ground. Such a loss of traction is sometimes called "diffing out".

2- Limited Slip Differential

Limited Slip Differential :-
When torque is applied ,the differential case will spin and throw the pinion into the pressure ring. The pressure ring is then pushed out against the clutch plates thereby squeezing them together This causes the wheels to gradually lock together, depending on the power applied, hence prevents differential action This effect limits the wheel spin during hard cornering and applies power to the wheels evenly when more power is applied to the wheels.

and you can see here the difference between "Open Differential" & "Limited Slip Differential" where Open on the left and Limited Slip on the right.

Petroleum onshore drilling rig

drilling rig is a machine that creates holes in the earth sub-surface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and are called augers

The main components of a petroleum onshore drilling rig :-

A crown block :- is the stationary section of a block and tackle that contains a set of pulleys or sheaves through which the drill line is threaded or sheaves through which the drill line  is threaded or reeved and is opposite and above the traveling block.

derrick :- is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a boomhinged at its base to provide articulation, as in a stiffleg derrick.

A traveling block :- is the freely moving section of a block and tackle that contains a set of pulleys or sheaves through which the drill line is threaded or  reeved and is opposite the crown block

A Swivel :- is a mechanical device used on a drilling rig that hangs directly under the traveling block and directly above the kelly drive, that provides the ability for the kelly to rotate while allowing the traveling block to remain in a stationary rotational position while simultaneously allowing the introduction of drilling fluid into the drill string.

rig standpipe :- is a solid metal pipe attached to the side of a drilling rig's derrick that is a part of its drilling mud system. It is used to conduct drilling fluid from the mud pumps to the kelly hose. Bull plugs, pressure transducers and valves are found on the rig standpipe.

A kelly :- refers to a type of well drilling device on an oil or gas drilling rig that employs a section of pipe with a polygonal or splined outer surface, which passes through the matching polygonal or splined kelly bushing and rotary table.

A rotary drive :- is a mechanical device on a drilling rig that provides clockwise rotational force to the drill string to facilitate the process of drilling a borehole. Rotary speed is the number of times the rotary table makes one full revolution in one minute.

A draw-works :- is the primary hoisting machinery that is a component of a rotary drilling rig. Its main function is to provide a means of raising and lowering the traveling blocks. The wire-rope drilling line winds on the draw works drum and extends to the crown block and traveling blocks, allowing the drill string to be moved up and down as the drum turns. 

blowout prevention (BOP) :- is a large, specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowout, the uncontrolled release of crude oil and/or natural gas from well. They are usually installed redundantly in stacks.

A mud pump :- is a reciprocating piston/plunger device designed to circulate drilling fluid under high pressure (up to 7,500 psi (52,000 kPa) ) down the drill string and back up the annulus.

A Drill bit :- is a tool designed to produce a generally cylindrical hole in the earth’s crust by the rotary drilling method for the discovery and extraction of hydrocarbons such as crude oil and natural gas.

A casing :- is a simple metal flange welded or screwed onto the top of the conductor pipe or the casing and forms part of the wellhead system for the well.

A standpipe :- is a solid metal pipe attached to the side of a drilling rig's derrick that is a part of its drilling mud system. It is used to conduct drilling fluid from the mud pumps to the kelly hose. Bull plugs, pressure transducers and valves are found on the rig standpipe.

SI Engine & CI Engine

Spark Ignition (SI) engine can be compared with Compression Ignition (CI) engine system in 7 aspects. Those 7 aspects are engine speed, cycle efficiency, fuel used, time of knocking, cycle operation, pressure generated and constant parameter during cycle.
Spark Ignition Engine (SI engine)
Compression Ignition Engine (Ci engine)
Engine speed
SI engines are high speed engines.
CI engines are low speed engines.
Cycle efficiency
SI engines have low thermal efficiency
CI engines have high thermal efficiency.
Fuel used
Petrol is used as fuel, which has high self ignition temperature.
Diesel is used as fuel, it has low self ignition temperature.
Time of knocking
Knocking takes place at the end of combustion.
Knocking takes place at the beginning of combustion.
Cycle operation
SI engine works on otto cycle.
CI engine works on diesel cycle.
Pressure generated
Homogeneous mixture of fuel, hence high pressure is generated.
Heterogeneous mixture of fuel, hence low pressure is generated.

And this is a simple Comparison show the main Difference between S.I & C.I engine

Various operations on lathe

various operations on lathe :-

a) Straight turning
b) Taper turning
c) Profiling
d) Turning and external grooving
e) Facing
f) Face grooving
g) Cutting with a form tool
h) Boring and internal grooving
i) Drilling
j) Cutting off
k) Threading
l) Knurling

Lathe machine

A lathe is a machine tool which turns cylindrical material, touches a cutting tool to it, and cuts the material. The lathe is one of the machine tools most well used by machining

The standard components of most lathes :-

• Bed: Usually made of cast iron. Provides a heavy rigid frame on which all the main components are mounted.
• Ways: Inner and outer guide rails that are precision machined parallel to assure accuracy of movement.
• Headstock: mounted in a fixed position on the inner ways, usually at the left end. Using a chuck, it rotates the work.
• Gearbox: inside the headstock, providing multiple speeds with a geometric ratio by  moving levers.
• Spindle: Hole through the headstock to which bar stock can be fed, which allows shafts that are up to 2 times the length between lathe centers to be worked on one end at a time.
• Chuck: 3-jaw (self centering) or 4-jaw (independent) to clamp part being machined.
• Chuck: allows the mounting of difficult workpieces that are not round, square or triangular. 
• Tailstock: Fits on the inner ways of the bed and can slide towards any position the headstock to fit the length of the work piece. An optional taper turning attachment would be mounted to it. 
• Tailstock Quill: Has a Morse taper to hold a lathe center, drill bit or other tool.
• Carriage: Moves on the outer ways. Used for mounting and moving most the cutting tools.
• Cross Slide: Mounted on the traverse slide of the carriage, and uses a handwheel to tools into the workpiece.
• Tool Post: To mount tool holders in which the cutting bits are clamped.
• Compound Rest: Mounted to the cross slide, it pivots around the tool post.
• Apron: Attached to the front of the carriage, it has the mechanism and controls for moving the carriage and cross slide.
• Feed Rod: Has a key way, with two reversing pinion gears, either of which can be meshed with the mating bevel gear to forward or reverse the carriage using a clutch.
• Lead Screw: For cutting threads.
• Split Nut: When closed around the lead screw, the carriage is driven along by direct drive without using a clutch.
• Quick Change Gearbox: Controls the movement of the carriage using levers.

Engine Types

Most common engines types :-

Four-Stroke Engine :-
four-stroke engine is an internal combustion engine that utilizes four distinct piston strokes (intake, compression, power, and exhaust) to complete one operating cycle. The piston make two complete passes in the cylinder to complete one operating cycle. An operating cycle requires two revolutions (720°) of the crankshaft. 

Diesel Engine :- 
An internal combustion engine that uses the heat of highly compressed air to ignite a spray 
of fuel introduced after the start of the compression stroke.
one cycle of a four-stroke
diesel engine :-
A. intake stroke
B. compression stroke
C. power stroke
D. exhaust stroke

Two-Stroke Engine :-

two-stroke engine is a type of internal combustion engine which completes a power cycle with two strokes of the piston during only one crankshaft revolution.
In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust functions occurring at the same time.

Wankel Engine :- 

A rotary internal combustion engine in which a triangular rotor turning in a specially 
shaped housing performs the functions allotted to the pistons of a conventional engine, thereby allowing great savings in weight and moving parts.
type of four stroke internal combustion engine without reciprocating parts. It consists 
of one or more approximately elliptical combustion chambers within which a curved 
triangular shaped piston rotates, by the explosion of compressed gas, dividing the 
combustion chamber into three gas tight sections

Atkinson Engine :-

Is a type of internal combustion engine. The Atkinson cycle is designed to provide efficiency at the expense of power density. A modern variation of this approach is used in some current hybrid electric applications.

Gnome Rotary Engine :-

The gnome rotary engine was a type of internal-combustion engine, usually designed with an odd number of cylinders per row in a radial configuration, in which the crankshaft remained stationary in operation, with the entire crankcase and its attached cylinders rotating around it as a unit.

the most common types of cylinder layout you'll find in engines today

  • Singles are typically used in motorbikes, snowblowers, chainsaws etc. 
  • V-twins are also found in motorbikes. 
  • The triple is almost unique to Triumph motorbikes where they call it the Speed Triple.
  • Inline-fours are the mainstay of car engines, as well as being found in some motorbikes too such as the BMW K1200S. 
  • Inline fives used to be used a lot in Audis but have found a new home in current Volvos. 
  • The V5 is something you'll find in some VWs. 
  • The V6 has the benefits of being smoother than an inline-four but without the fuel economy issues of a V8. 
  • Boxer engines are found in BMW motorbikes
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