Automotive Engineering 101: Internal Combustion Engine

Define the engine as a mechanical system that converts chemical and heat energy from fuel into mechanical energy, and classify engines by cycles, cylinder count and arrangement, and engine position.

Explore the engine's main parts, including the block, cylinder head, camshaft, and crankshaft, and how pistons, valves, rings, and the timing chain or belt drive the cycle.

Explore how a four-stroke engine operates through intake, compression, power, and exhaust strokes, with valve actions, piston movement between top and bottom dead centers, air-fuel intake, ignition, and exhaust release.

Diesel engines rely on compression ignition with no spark plug, injecting fuel at the end of compression via a diesel injector to avoid ignition as intake air reaches 0.1 bar.

Explore the rotary engine, or Wankel engine, an internal combustion engine that uses a triangle rotor and apex seals to run the intake, compression, ignition, and exhaust cycle.

Explore the single overhead camshaft design, with the cam in the cylinder head directly actuating lifters and valves to minimize vibration and allow 3–4 valves per cylinder.

Explore the engine lubrication system, where oil reduces friction, wear, and heat. Understand viscosity, viscosity index, viscosity rating, and boundary lubrication, including gas-tight sealing between cylinder and piston ring.

Learn how fuel combustion releases energy, forms carbon monoxide and unburned hydrocarbons, and how lean mixtures and exhaust gas cooling reduce nitrogen oxide emissions and boost fuel economy.

The ECU uses data from air flow sensors to modulate fuel injection, illustrated by vane-type meters that convert flap position to voltage via a potentiometer. This vane design is obsolete due to airflow resistance and undesired performance, even with a shock absorber.

Explore how the throttle body regulates intake air with a pedal-controlled flap, including the idle port, and the role of throttle position sensors—switch or potentiometer—in feeding the ECU.

Examine the mechanical ignition system, camshaft-driven contact breaker, condenser, and distributor routing sparks to four cylinders, and why this obsolete system lags electrical ignition in timing and emissions.

Learn how the ecu uses camshaft, crankshaft, and knocking sensor inputs along with manifold absolute pressure, coolant temperature, throttle and accelerator pedal positions, and wheel speed signals to control ignition.