Overview
This lecture reviews the main types of engine layouts found in automobiles, highlighting their structure, characteristics, advantages, and disadvantages.
Internal Combustion Engine Basics
- The cylinder is the engine's power unit, burning fuel to create mechanical energy.
- More cylinders usually mean more engine power.
- Common car engines have 4, 6, or 8 cylinders.
Single Cylinder Engine
- Contains one piston/cylinder; common in motorcycles, scooters, go-karts, and ATVs.
- Simpler, cheaper, and easier to cool than multi-cylinder engines.
- Produces high torque at low revs but vibrates more and needs balancing devices.
- Uses heavier flywheels, resulting in slower engine speed changes.
Inline (Straight) Engine
- Cylinders are aligned in a single row with no offset.
- Simple design, commonly used for 4, 6, or 8 cylinders.
- Compact, affordable, fuel-efficient but less rigid and prone to overheating.
- Higher center of gravity and can be noisy on rough roads.
V Engine
- Cylinders are arranged in two banks forming a "V" shape, joined to one crankshaft.
- Common for engines over four cylinders (e.g., V6, V8, V12).
- Compact, smooth, balanced, and allows for more power in less space.
- More complex, heavier, expensive, and harder to cool; less fuel-efficient.
Flat & Boxer Engines
- Flat engines have horizontally opposed cylinders at 180° angle.
- Boxer is a type of flat engine where opposing pistons move together.
- Perfect balance, low center of gravity, improved aerodynamics, but wide and hard to service.
- Used by Porsche, Subaru, and Toyota in select models.
W Engine
- Features three or four cylinder banks sharing a common crankshaft.
- Compact but complex, used in luxury/exotic cars needing high power in small space.
- Rare due to manufacturing difficulties.
Rotary (Wankel) Engine
- Uses a rotating triangular rotor instead of pistons.
- Compact, lightweight, low center of gravity, and smooth operation.
- Poor fuel efficiency and emissions, needs frequent maintenance; mainly famous from Mazda RX series.
Radial Engine
- Cylinders arranged like spokes around a crankcase, mainly used in aircraft.
- Delivers high power, unique firing order, and uses a master connecting rod.
X, U, and H Engines
- X engine: Four banks of cylinders; rare and complex.
- U engine: Two separate inline engines joined via a shared output shaft.
- H engine: Two flat engines stacked and geared together, offering mechanical balance but heavy.
Opposed Piston Engine
- Two banks of cylinders opposite each other; increased efficiency but added mechanical complexity.
Key Terms & Definitions
- Cylinder — Chamber in an engine where fuel is burned to produce power.
- Crankshaft — Shaft driven by pistons to transfer mechanical power.
- Inline Engine — Cylinders arranged in a straight line.
- V Engine — Cylinders arranged in a V pattern.
- Flat/Boxer Engine — Cylinders horizontally opposed, with boxer engines having synchronized piston movement.
- W Engine — Multiple cylinder banks in a W configuration.
- Rotary (Wankel) Engine — Engine using a rotating rotor instead of pistons.
- Radial Engine — Cylinders radiate from a central crankshaft.
- Opposed Piston Engine — Two pistons in one cylinder, moving toward each other.
Action Items / Next Steps
- Review illustrations of each engine layout for better understanding.
- Compare the pros and cons of each design for potential exam questions.