How does a truck engine work?

Truck engines, like most internal combustion engines, work based on a series of controlled explosions that convert energy stored in fuel into usable power to drive the wheels. Here’s a simplified breakdown of the process in a four-stroke diesel engine, which is the dominant type in heavy-duty trucks:

1. Intake Stroke:

  • The piston moves down in the cylinder, creating a vacuum.
  • An intake valve opens, allowing air to rush into the cylinder.
  • The fuel injector remains closed in this stroke for diesel engines.

2. Compression Stroke:

  • Both the intake and exhaust valves close.
  • The piston moves up in the cylinder, compressing the air trapped inside.
  • This compression significantly increases the air temperature.

3. Power Stroke:

  • At the top of the compression stroke, the fuel injector sprays a fine mist of diesel fuel into the hot compressed air.
  • The high temperature and pressure cause the fuel to ignite spontaneously, creating a controlled explosion.
  • This explosion pushes the piston back down the cylinder, generating power.

4. Exhaust Stroke:

  • The piston moves back up the cylinder as the exhaust valve opens.
  • The burned exhaust gases are pushed out of the cylinder through the open exhaust valve.
  • The cycle then repeats, starting from the intake stroke again.

Additional components:

  • Crankshaft: The connecting rod attached to the piston is connected to the crankshaft, which converts the reciprocating motion of the piston into rotary motion.
  • Camshaft: This shaft controls the opening and closing of the intake and exhaust valves using lobes and followers.
  • Turbocharger (optional): In many modern truck engines, a turbocharger is used to force more air into the cylinder during the intake stroke, increasing power and efficiency.

Key differences between diesel and gasoline engines:

  • Fuel ignition: Diesel engines rely on the high temperature of compressed air to ignite the fuel, whereas gasoline engines use spark plugs to create the ignition spark.
  • Fuel injection timing: Diesel fuel is injected just before the power stroke, while gasoline is injected during the intake stroke.
  • Air-fuel ratio: Diesel engines use a leaner air-fuel mixture (more air, less fuel) compared to gasoline engines.

This is a basic overview of how a truck engine works. The actual process involves various other components and complex interactions, but this explanation should provide a good understanding of the fundamental principles.