PSA Airlines Canadair Regional Jet Systems (PSA-CRJ) Practice Exam

How is fuel heated before entering the engine?

1. By electrical heating elements

2. Using ambient air temperature

3. By a fuel/oil heat exchanger

4. By engine exhaust heat

The correct answer is: By a fuel/oil heat exchanger

Fuel is heated before entering the engine primarily through a fuel/oil heat exchanger. This system takes advantage of the heat generated by the engine oil, which warms the fuel as it passes through the exchanger. The heat transfer ensures that the fuel reaches an optimal temperature for combustion, improving efficiency and performance. The use of a fuel/oil heat exchanger is advantageous because it utilizes existing heat from the engine system, making it an efficient way to prepare fuel without requiring additional energy sources. This method also helps to prevent fuel from becoming too cold, especially during low-temperature operations, which can negatively affect the fuel's flow properties and combustion efficiency. While electrical heating elements, ambient air temperature, and engine exhaust heat can influence fuel temperature under certain circumstances, the specific role of a fuel/oil heat exchanger makes it the most direct and effective means of heating fuel prior to engine entry. This ensures that the fuel is appropriately conditioned for the conditions in which the engine operates.