How does a turbocharger enhance engine efficiency?

A turbocharger enhances engine efficiency primarily by forcing more air into the engine. This process increases the amount of oxygen available for combustion, allowing for a more complete burn of the fuel. As a result, the engine can produce more power without increasing its displacement or size. When more air is forced into the combustion chamber, it enables the engine to burn more fuel efficiently, which leads to improved power output and better fuel economy.

Expanding on this, while reducing fuel consumption is an effect of the improved air-fuel mixture that the turbocharger facilitates, the mechanism that directly contributes to efficiency is the increased airflow. Cooling the air-fuel mixture is beneficial in terms of performance but is not a primary function of a turbocharger itself. Increasing engine size does not apply here, as a turbocharger's purpose is to enhance the performance of an engine without the need for larger displacement.