Straight Engine (Inline Engine):
All cylinders are in a single line, running vertically along the crankshaft.
Simpler design, easier to manufacture.
Examples: Inline-4 (common in many cars), Inline-6 (often in larger cars).
V Engine:
Cylinders are arranged in two banks forming a "V" shape, with a common crankshaft.
Creates a compact design for more cylinders compared to straight engines.
Offers good balance and power delivery.
Examples: V6 (common in many cars), V8 (often in performance cars).
Flat Engine (Horizontally Opposed Engine):
Cylinders are positioned horizontally on opposite sides of a central crankshaft, resembling a pancake.
Low center of gravity improves handling.
Can be wider than other layouts.
Example: Boxer engine (used in Subaru cars).
There are other less common configurations like W engines (rarely used due to complexity) and rotary engines (known for smoothness but have emissions challenges).
The choice of engine layout depends on various factors:
Power requirements: More cylinders generally provide more power, but come with size and weight increase.
Vehicle size and weight: Smaller cars might opt for inline engines for better space utilization.
Handling characteristics: Flat engines can improve handling due to their lower center of gravity.