What does the 50 at the back of an Audi mean?

[Ruby]

Audi's 50 represents the displacement of the engine used in the car, allowing for better differentiation through numbers. The numerical badge at the rear of the car also signifies the vehicle's configuration and grade. The 50 actually represents the G-value, which can be understood as the car's acceleration performance relative to the gravitational acceleration G. The higher the number, the better the engine's power performance. Car Displacement Classification The classification of car levels is determined by the size of the displacement. Mini cars have a displacement of 1.0L or less; compact cars have a displacement ranging from 1.0L to 1.6L; mid-size cars have a displacement ranging from 1.6L to 2.5L; executive cars have a displacement ranging from 2.5L to 4.0L; and luxury cars have a displacement greater than 4.0L. Adaptability: In cars, how well the engine and the vehicle are matched has a significant impact on the car's fuel economy. If a small-displacement engine is poorly matched, it may not be more fuel-efficient than a large-displacement engine and could even consume more fuel than a large-displacement engine.