Oilers/Plant Tenders (HHC) Civil Service Practice Exam

In which type of engine is the quantity of lubricating oil used greater?

1. 4-cycle engine

2. 2-cycle engine

3. Diesel engine

4. Electric engine

The correct answer is: 2-cycle engine

The choice of a 2-cycle engine as the answer reflects its operating principles, which fundamentally influence its oil usage. In a 2-cycle engine, lubrication occurs through the fuel mixture; the oil is mixed with the fuel before combustion. As a result, a higher quantity of lubricating oil is consumed since every fuel consumption includes a portion of oil, leading to it being exhausted with the combustion gases. In contrast, a 4-cycle engine separates the oil system from the fuel system. It typically retains its lubricating oil and uses it more efficiently through a dedicated lubrication system, leading to lower overall consumption of oil during operation. Diesel engines also use a lubricating system that recirculates oil to minimize waste, although they can have different oil requirements compared to gasoline engines due to their heavier-duty design. An electric engine, being non-combustion, does not require lubricating oil for its operation at all, as it functions using electric power rather than fuel. Thus, the 2-cycle engine indeed utilizes a greater quantity of lubricating oil when compared to other engine types mentioned.