Cars Engines

Cars Engines

The engine is always referred to as the heart of a vehicle. It is connoted with the term heart because it is the most important part of a vehicle. An engine is a machine which converts energy to mechanical motion. It is the engine that converts the flow of a fluid into mechanical energy.

Most of the modern cars today are incorporated with an internal combustion engine. The internal combustion engine ignites a fuel along with an oxidizer in a combustion chamber. The high temperature and pressure produced by the combustion process directly applies force to the movable part of the engine which could be the piston or the turbine blades to generate mechanical energy or to enable the vehicle to move.

Car engines may differ in design but certain basic elements always remain the same.

There are different types of car engines and they can be classified according to:

Type of Fuel: The most common classification of an engine could be done on the basis of the fuel which it runs on. The two types of fuels that engines use to convert energy to mechanical work are gasoline and diesel oil. Recently a number of alternate fuels like electricity, ethanol, methanol, hydrogen, propane and natural gas are being considered due to the rising prices of gasoline and diesel.

Ignition System: The term ignition relates to the medium by which the fuel is converted to energy. There are two ways by which the fuel is ignited inside the car engine, spark ignition and compression ignition. Gasoline engines use spark ignition while diesel engines use compression ignition.

Block Geometry or Cylinder Arrangement: The cylinders of a car are arranged in the following ways: V type, inline and horizontally opposed and slant. In the case of an inline engine the cylinders are arranged in a row, in the V type the cylinders form two angled rows to form a V, in the horizontally opposed engine the cylinders are horizontal and opposing each other and in the case of the horizontally slant engine the cylinders are arranged in a single row forming half a V.

Number of Cylinders: The number of cylinders in a car range from 3 to 12. The number of cylinders indicate how the smooth running of the car. The more the number of cylinders the smoother the car runs. A car that has 5 cylinders will run with more ease than a car with 3 cylinders. The number of cylinders also contributes to the amount power output; more cylinders, more power. However, this is not always a good indicator of power output. A turbocharged, four-cylinder engine can produce more power than a normally aspirated six-cylinder engine.

Strokes per Cycle: Strokes per cycle indicate the number of times the piston travels up and down during one cycle. Engines today are incorporated with four strokes per cycle that is intake, compression, power, and exhaust.

Combustion Chamber: There are mainly 3 shapes of combustion chambers that are used in an engine: hemispherical, wedge, and pancake. The hemispherical shape is the most common out of all. The hemispherical, also called "hemi-head," is designed with the intake and exhaust valves angled and opposing each other, in the wedge shape the valves are side by side and slightly angled and in the pancake shape the valves are vertical.

Camshaft Location: The camshaft in generally located in the cylinders head or engine block. Car engines which have the camshaft located in the cylinders head are called overhead cam (OHC) engine. There are two types of overhead cams engines they are Dual overhead cam and Single overhead cam. A dual overhead cam (DOHC) engine uses two camshafts, one for the intake valves and the other for the exhaust valves. Single overhead cam (SOHC) engines use one cam for both the intake and exhaust valves. Engines with the camshaft in the block make use of push rods to move the valves.

Cooling System: Car engines could ne liquid cooled or air cooled. Without a cooling system, car engines will quickly destroy themselves due to extreme temperatures. Air cooled engines have cooling fins surrounding the cylinders which carry away the heat which surrounds the cylinders. Liquid cooled engines are incorporated with water jackets in the cylinder block or cylinder head through which the coolant circulates and does away with the heat. Liquid cooled engines are more widely used in the modern day.

Last Updated on 1/9/2012