What is the primary purpose of an oil-to-fuel heat exchanger?

The primary purpose of an oil-to-fuel heat exchanger is to increase the temperature of the fuel, making option C the correct answer. This component allows the engine to achieve optimal performance by ensuring the fuel is at the right temperature for efficient combustion.

When fuel is warmed before entering the combustion chamber, it helps in reducing viscosity, enhancing atomization during injection. This leads to a more complete and efficient combustion process, which can improve engine efficiency and reduce emissions.

In contrast, while measuring oil flow is an important function in many systems, this role is not the main function of the heat exchanger. Cooling oil can be necessary in certain contexts, but the heat exchanger's primary function remains focused on raising fuel temperature. Additionally, heating the fuel is the goal of the heat exchanger, rather than being a simple cooling process or not functioning at all.