Which of the following can cause premature wear due to abrasive ingestion?

Premature wear in engines due to abrasive ingestion primarily occurs when dust and dirt particles enter the engine's intake system. These particles can become trapped in the combustion chamber, where they can damage moving parts, such as pistons, cylinder walls, and bearings, leading to increased wear and potential engine failure.

The presence of dust and dirt is particularly problematic because these particles are often harder than the materials used in engine components. When they come into contact with these components during operation, they can create micro-scratches and wear patterns that contribute to the degradation of essential surfaces, ultimately affecting the engine's performance and longevity.

In contrast, oil additives are designed to enhance lubrication and protect engine components from wear. Contaminated fuel may impact engine performance but does not directly lead to abrasive wear in the same manner as physical particles. Poor engine design can lead to various issues but does not inherently cause wear from abrasive materials unless it facilitates their introduction into the engine. Thus, the ingestion of dust and dirt particles is the most significant cause of abrasive wear among the listed options.