Sunday, 20 September 2020
ENGINEERING CONCEPTS

Four Stroke and Two stroke Cycle Engines

Four stroke cycle engines are.

  1. Petrol Engine
  2. Diesel Engine

Petrol Engine:

Petrol engine works on Otto cycle principle. In this petrol engine air and fuel mixture is drawn in the engine cylinders. In this engine ignition is takes place due to spark, therefore this engine is called spark ignition engine.

Four stroke cycle engine
Four stroke cycle engine

Diesel Engine:

Diesel engine works on diesel cycle principle. In this engine only air is drawn in suction stroke. In this engine fuel is injected with the help of fuel injector and ignition takes place, Therefore this engine called compression ignition system.

Two stroke cycle engines

In this two stroke cycle engine suction stroke and Exhaust strokes are eliminated and values are replaced by ports. In this engine exhaust gases are driven out from engine cylinder by the fresh charge of fuel entering the cylinder nearly at the end of the working stroke.

Two Stroke cycle engine
Two Stroke cycle engine

Cooling systems:

Cooling systems are mainly two types they are.

  1. Air cooling
  2. Water cooling

The air cooling systems are used in scooters and motor cycles. When the combustion system suddenly rises of pressure accompanied by metallic hammer like sound is called detonation.

Auto – Ignition refers to ignition of combustion without the necessity of a flame. Indicated power means the total power developed by combustion of fuel in the combustion chamber.

Volumetric efficiency:

Volumetric efficiency means the ratio of actual volume of the charge drawn in during the suction stroke to the swept volume of the piston.

Fuel air ratio: The ratio of the mass of fuel to the mass of air in the fuel air mixture.

Specific fuel consumption:

The specific fuel consumption is the mass of fuel consumed per KW developed per hour.

Thermal efficiency:

The thermal efficiency is the ratio of indicated work done to energy supplied by the fuel indicated thermal efficiency.