Lenoir cycle | Working process | Thermal efficiency

The Lenoir cycle is a thermodynamic cycle that can be invented by Jean Joseph Etienne Lenoir in 1860 is often used to model a pulse jet engine. 

Process of Lenoir cycle :


All type of process individually done in a heat engine in Lenior cycle. 

The Lenoir cycle consists of four processes which are following below. 
  • constant-volume gas expansion process. From the diagram shown below the ideal gas in the system absorbs some amount of heat from the heat source at a high temperature and then expands thus the work was done on surroundings. 
  • reversible adiabatic gas expansion process. In this process, the system is thermally insulated. The gas expands continuously and does work on surrounding, which causes the system to cool to a lower temperature. 
  • reversible isothermal gas compression process. In this process, work has done surrounding gas and cause a loss of heat.
  • reversible adiabatic gas compression process. In this process, surrounding continue to do work to a gas, which causes the temperature to rise back to high temperature attain in the first process. 
Lenoir cycle PV and TS Diagram
Lenoir cycle PV and TS Diagram


The thermal efficiency of Lenoir cycle : 

Thermodynamically, the efficiency of Lenoir cycle is given by

ŋLenoir = Work done by the system / Heat supplied to the system

CAM full form

What is the full form of CAM?

Answer : 


  • Computer-Aided Manufacturing

What does CAM mean?

CAM is computer-controlled machinery to automate the manufacturing process. 

CAM uses CAD software created models and assemblies to generate tool paths that drive machine tools to turn a design into the physical parts.


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Technical terms and their full form used in manufacturing

VMC full form

What is the full form of VMC?

Answer : 

  • Vertical Milling Center

What does VMC mean?

VMC is a specific type of milling machine which is controlled by CNC. The cutting head of this type of machine is vertical where a spindle runs in a vertical axis known as the z-axis. 


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Concept of production

Production is the transformation of inputs into output where inputs are used in many ways such as land, labour, capital, raw material etc. 

Production concept emphasis on low production costs, and high production efficiency and mass production simply said a large amount of the cheapest goods. 


The function of production :

The function of production is the technological relationship between inputs and output in physical terms. An algebraic expression for production is Q = f (K, L)

Where Q = The quantity of output produced per unit time
K = Capital 
L = Labour 


Characteristics of the production system : 

  • The production system has its own objective.
  • The system transforms the various inputs to the useful output.
  • Does not operate in isolation from the other organization system. 
  • There exists a procedure which controls and improve system performance. 

Types of production : 

  • Continuous production 
  • Batch production 
  • Mass production 
  • Job-shop production 

Definition of production

Production is the method of turning raw materials or inputs into finished goods or products means the creation of something from basic inputs. Production is the process of transformation because it is done to satisfy human wants. The process of transformation is done in the following ways. 

  1. Disintegration: One input is used to produce many types of output. 
  2. Integration or Assembly: Many inputs are used to produce only one output. 
  3. Service: Value of the product is increased by providing services. 

Automobile parts explain

What is the clutch?
The clutch is a mechanical device, which is used to connect or disconnect the source of power from remaining parts of the power transmission system.  Read more

What is flywheel?
A heavy revolving wheel in a machine which is used to increase the machine's momentum and thereby provide greater stability or a reserve of available power.  Read more

Steering and Wheel allignment

Principle of the steering system
The primary function of the steering system is to achieve accurate angular motion of the front wheels to negotiate a turn. This can be done through linkage and steering gear which convert the rotary motion of the steering wheel into the angular motion of the front road wheels.  Read more 

The requirement of a good steering system
The steering system should be very accurate and easy to handle. 
The effort required to Spear should be minimal and must be not tiresome to the driver. Read more 

What is a wheel alignment?

Wheel alignment is the positioning of the steered wheels to achieve the directional stability during straight-ahead position, perfect rolling condition on steering and recovery after completing the turn.  Read more

Steering axis inclination :
The inclination of the kingpin from vertical is called the king inclination or steering axis inclination. Steering axis inclination causes both front wheels to gain positive camber because they steer away from the centre.  Read more 

What is a caster?
The caster angle is called the angle between the kingpin centre line for the steering axis and the vertical in the wheel plane.  Read more

What is camber?
Read more 

What are Toe-in and Toe-out?
Toe-in is the amount by which the front wheels are mounted closer together on the front than on the back when the vehicle is stationary and viewed from the top. The wheel can be set closer to the rear than to the front, in which case the difference of the distances between the front and rear wheels is called toe-out.  Read more 

Correct steering angle :
cotø - cotθ = c / b  this is the fundamental equation for correct steering. Read more

Ackerman steering mechanism :
Read more 

Fuels used in Automobile

Classification of fuels
Types of fuels such as Liquid fuels, Gaseous fuels, Solid fuels, Viscous liquid fuels, Dual fuels  Read more 

Gaseous fuels :
Gaseous fuels are ideal and pose very few problems in using them in internal combustion engines. Being gaseous, they mix more homogeneously with air and eliminate the distribution and starting problems that are encountered with liquid fuels.  Read more 

Solid fuels
Solid fuels are categories by following below :
  • Biomass ( 5 C and 37 P )
  • Charcoal (27 P )
  • Coal (13 C and 64 P )
  • Oil shale ( 7 C and 12 P )
  • Peat ( 2 C and 4 P )
  • Wood fuel ( 1 C and 9 P )  Read more

Liquid fuels : 
Read more 

Chemical structure of petroleum :
Petroleum, as obtained from the oil wells, is predominantly a mixture of many hydrocarbons with differing molecules structure. It also contains a small amount of sulphur, oxygen, nitrogen and impurities such as water and sand. Read more 


Automobile layout

Front-wheel drive :
A transmission system that provides power to the front wheels of a motor vehicle. Read more

Rear-wheel drive :
A transmission system that provides power to the rear wheels of a motor vehicle. Read more 

Braking system

Principle of the braking system :
The braking system is one of the most important control components of the vehicle. There are different types of brakes are used in various need. They are required to stop the vehicle within the smallest possible distance and this can be done by converting the kinetic energy of the vehicle into the heat energy which is dissipated into the atmosphere.  Read more 

Braking requirements
The brakes must be strong enough to stop the vehicle within a minimum distance in an emergency condition but this should also be consistent with safety. The driver must have proper control over the vehicle during emergency braking condition and the vehicle must not skid.  Read more 

Brake efficiency and stopping distance
The brake efficiency usually varies from 50 to 80 % which enable the vehicle to stop within a reasonable distance. Approximate stopping distance at different vehicle velocities for various conditions of brakes are different. However, the minimum allowable limit of brake efficiency for any vehicle is 50 % for foot brakes and 30% for hand brakes. Read more 

Types of brakes :

There are different types of automotive brakes may be used according to the following considerations :
Purpose
Location 
Construction 
Method of actuation 
Extra braking effort  Read more

Drum brake :
In this types of brakes, a brake drum is attached concentrically to the axle hub whereas on the axle casing is mounted a backplate. In case of the front axle, the brakes plate is bolted to the steering knuckle. The backplate is made of pressed steel sheet and is ribbed to increase rigidity and to provide support for the expander, anchor and the brake shoes are protects the drum and shoe assembly from dust and mud.  Read more 

Disc brake
In between each disc and the piston, there is a friction pad held in position by retaining pins, spring plates etc. Passages are drilled for the fluid in the calliper to enter or leave each housing. These passages are also connected to another passage for bleeding. Each cylinder contains a rubber sealing ring between the cylinder and the piston.  Read more

Engine cooling system

Engine cooling system
The cooling system keeps the engine from getting not too hot but at the same time not to keep it too cool either.  Read more

Purpose of the colling system
cooling system must be provided not only to prevent damage to the vital parts of the engine, but the temperature of these components must be maintained within certain limits in order to obtain maximum performance from the engine. Hence, a cooling system is needed to keep the engine from not getting so hot as to cause problems and yet to permit it to run hot enough to ensure maximum efficiency of the engine.  Read more 


    Carburetion and Carburetor

    What is carburetion?
    The amount of formation of a combustible air-fuel mixture by mixing the proper amount of fuel with air before admission to engine cylinder is called carburetion. Read more 

    Factors affecting carburetion

    The engine Speed 
    The vaporization characteristics of the fuel 
    The temperature of the incoming air 
    The design of the carburettor  Read more

    What is carburettor?

    Carburetion is the process of formation of a combustible air-fuel mixture by mixing the proper amount of fuel with air before admission to the engine cylinder. The device with does this job is called carburettor. Read more

    Parts of carburettor and function

    Fuel strainer
    Float chamber
    Main fuel metering and idling nozzles 
    Chock and throttle  Read more 

    Carburettor size :

    The size of a carburettor is generally given in terms of the diameter of the venturi tube in mm and the jet size in hundredths of a millimetre.  Read more

    Air-fuel mixture

    The three types of mixtures are following below :
    Chemically correct mixture 
    Rich mixture
    Lean mixture  Read more

    Simple carburettor :

    Carburettors are highly complex provides an air-fuel mixture for cruising or normal range at a single speed. Later, other mechanisms to provide for the various special requirements like starting, idling, variable load and speed operation and acceleration will be included. Read more 

    Modern carburettor

    There are some new systems used in the modern carburettor for meeting the requirement of vehicles. Anti-dieseling system, Richer coasting system, Acceleration pump system, Economizer or Power enrichment system  Read more

    Types of carburettor

    There are three general types of carburettor depending on the direction of flow of air.
    Up draught type 
    Down draught type
    Cross draught type  Read more 

    SU carburettor

    SU carburettors, in general, a constant torque type carburettor. Zenith, Solex and carter carburettor are an example of this type. SU carburettor differs completely from them being constant vacuum or constant depression type with automatic variable chock. Read more 

    Solex carburettor : 

    The Solex carburettor is famous for its ease of starting, good performance and reliability. It is one type of down draught carburettor. This carburettor is made in various models and is also used n many automobile engines.  Read more

    Carter carburettor

    Carter carburettor is multiple jets, plain tube type of carburettor with only one adjustment which is for idling or low-speed operation. Carter carburettor is normally used in Jeeps. Read more