With increasing vehicle speed, back pressure will________________?
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Answer: B. increase
Explanation
As vehicle speed increases, the volume of exhaust gases passing through the exhaust system rises significantly. This higher volumetric flow rate creates greater flow restriction and frictional resistance within mufflers and pipes. Consequently, the back pressure exerted against the engine exhaust stroke increases proportionally with vehicle speed. Back pressure refers to the pressure opposing the outward flow of exhaust gases from engine cylinders. Exhaust system components including catalytic converters and mufflers create natural flow restrictions for acoustic dampening. Excessive back pressure forces engines to expend more mechanical work expelling exhaust gases, reducing net power output.
Decreasing back pressure at high speeds contradicts the basic fluid dynamics of increased volumetric flow through pipes. Remaining unaffected is impossible since higher gas velocities through fixed pipe geometries inevitably increase frictional losses. Stating that back pressure depends entirely on other factors ignores the direct hydrodynamic relationship with vehicle speed.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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