Practice question

What is the primary function of a commercial vehicle's exhaust brake (freno de escape)?

To purify exhaust gases before release
To restrict the flow of exhaust gases via a butterfly valve in the exhaust manifold, creating backpressure in the engine cylinders that retards piston movement and slows the vehicle
To increase engine horsepower during uphill climbs
To cool the turbocharger

Answer: B — To restrict the flow of exhaust gases via a butterfly valve in the exhaust manifold, creating backpressure in the engine cylinders that retards piston movement and slows the vehicle

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