Lecture Notes: How a Car Engine Works

Introduction

• Presenter: Jake O'Neal, creator of Animagraffs
• Focus: Explanation of how a car engine functions

Single Piston and the Four Stroke Cycle

1. Piston Basics
   • Piston's movement defines a stroke (up or down)
2. Four Stroke Cycle
   • Intake:
     • Piston descends
     • Air-fuel mixture enters cylinder through intake port
     • Intake valves open
   • Compression:
     • All valves closed
     • Piston rises
     • Compresses fuel-air mixture for combustion
   • Power Stroke:
     • Electrical spark ignites mixture
     • Combustion forces piston down
     • Power transferred to crankshaft via connecting rod
   • Exhaust:
     • Piston rises again
     • Spent mixture exits through open exhaust valves and port

Connecting Multiple Pistons

• Pistons fire in turns for smooth power (firing order: 1-3-4-2)
• Camshafts with cams open spring-loaded valves in sequence
• Cam gears and timing belt/chain link components to crankshaft
• Crankshaft:
  • Transforms piston power into rotational motion
  • Has counterweights for balanced revolutions
  • Measured in RPM (revolutions per minute)

Engine Structure

• Engine Block:
  • Houses crankshaft and cylinders
• Cylinder Head:
  • Contains valves, ports, cams
• Flywheel:
  • Connects to transmission and starter
• Cylinder Configuration:
  • Example: Four cylinders in a row
  • Other configurations: V6, V8, etc.

Supporting Systems

Air Intake

• Air enters through an air filter
• Mixes with fuel in intake manifold
• Sucked into cylinders via intake ports

Fuel System

• Fuel pump carries gas from tank through fuel filter
• Fuel injectors spray gas into intake port

Cooling System

• Purpose:
  • Prevents overheating
  • Uses antifreeze as coolant
• Components:
  • Coolant channels around cylinders and through heads
  • Radiator with tubes and fins
  • Water pump maintains flow and pressure
  • Thermostat regulates temperature and flow direction

Electrical System

• Spark Plug:
  • Ignites fuel-air mixture
  • Insulated by porcelain
• Coil Pack:
  • Delivers current directed by ECM (Engine Control Module)
• ECM:
  • Controls spark timing, valve timing, air-fuel ratio
• Alternator:
  • Converts mechanical energy to electricity
  • Charges battery and powers systems
• Battery:
  • Powers starter motor

Oil System

• Functions:
  • Lubricates, cleans, prevents corrosion, seals, cools
• Components:
  • Oil rings on piston heads
  • Oil galleries in engine
  • Oil pump for pressure
  • Oil pan for storage
  • Oil filter for cleanliness

Exhaust System

• Exhaust Manifold:
  • Collects gases from cylinders
• Catalytic Converter:
  • Captures toxic chemicals
• Muffler:
  • Reduces noise

Full Model Overview

• Summary of the engine and systems functioning together as one unit