Systems in an automobile

What Is an Engine?

ENGINE IS THE HEART OF THE AUTOMOBILE

IT GENERATES MOTIVE POWER FOR LOCOMOTION
IT CONVERTS CHEMICAL ENERGY OF THE FUEL TO
MECHANICAL ENERGY
ENGINE DEVELOPS POWER & TORQUE
TORQUE: – Is the capacity to do work
Measured in Kg-m, N-m, Lb-ft
POWER: – How fast the work can be done
Measured in – Horsepower, Kilo watt

before we explain more about engine you must know the Various Systems of an Automobile

a. power train system

• power plant (power generation – engine)

• engine

• fuel system

• intake system

• exhaust system

• cooling system

• drive line (power transmission)

• clutch

• gear box/transmission

• transfer case

• differential

• wheels/tires

b. running system.

• suspension

• steering

• braking

c. comfort system

• Hvac/ac/heater system

• seating/upholstry/facia/instruments

• audio/video

A four-stroke engine is an internal combustion engine that utilises four distinct piston strokes (intake, compression, power, and exhaust) to complete one operating cycle.

Classification of engines

ENGINES CAN BE CLASSIFIED IN MANY WAYS :

By Mechanical construction – 4 Stroke/2-Stroke
By type of Ignition – Compression Ignition/Spark Ignition
COMPRESSION IGNITION ENGINES

Basically, Diesel engines
Use diesel fuel
Combustion is initiated by heat, on its own
SPARK IGNITION ENGINES
Basically, Petrol engines, LPG engines, CNG engines
Use leaded or unleaded petrol, Alcohol, LPG or CNG
Combustion is initiated by a spark from a spark plug

Diesel engine

diesel engines are compression ignition engines & use diesel fuel
diesel engines are broadly classified as direct injection (di) and
indirect injection (Idi)

direct injection engine (di)

on direct injection diesel engines, fuel is sprayed directly on top of
the piston.

Highly fuel efficient
Noisy
Easy cold starting ability
INDIRECT INJECTION ENGINE
ON INDIRECT INJECTION DIESEL ENGINES, FUEL IS SPRAYED ON TO A SEPERATE
PRE-CHAMBER.
Less fuel efficient
Less Noisy/smoother
Requires pre-heating for starting.

petrol/cng/lpg engines

petrol engines are spark ignition engines & use gasoline/cng/lpg fuel petrol engines are broadly classified as carbureted and fuel injected engine

carbureted engine

on carbureted engine, the petrol & air are mixed in the carburetor before being sent into the engine.

fuel injected engine

On fuel injected engines, the petrol is injected separately, and the petrol and air are mixed inside the cylinder.

fuel injected engines can be further classified as:

single/multi point fuel injection, where the fuel is injected outside the cylinder gasoline direct injection (gdi), where the fuel is injected directly into the engine cylinder

internal combustion engine

reciprocating
rotary
Gas Turbine

reciprocating divided into: 4stroke and 2 stroke.

4stroke divided into:

compression ignition (diesel)

indirect injection • Xd3p • Xdp 4.90 • Sd 25

direct injection • Mdi 3200 • Sz 2600 (Scorpio) • Nef Na (Loadking) • Simpson S4 • Greaves

spark ignition (gasoline/lpg/cng)

carbureted • F4-134 • P 2150 • P2150 Cng

single point injection

multi point injection • Renault F4r • Isuzu

thermal efficiency

typical efficiencies

petrol – 25%

diesel idi – 28-30%

diesel di – 32-33%

fuel efficiency (fuel consumption)

fuel efficiency is a combination of engine efficiency, vehicle paramters & driving pattern

engine efficiency + transmission efficiency (clutch+gearbox+differential+ wheels + tyres) + weight/load/speed + aerodynamic parameters (drag – body shape) + driving pattern (driving style & traffic conditions)

fuel efficiency – kms/lit or lit/100 kms.

engine parameters