Question

question 7 of 10
in which step of the four - stroke engine cycle does the car release $\ce{co_{2}}$, $\ce{h_{2}o}$, and $\ce{co}$?
\\(\bigcirc\\) a. compression and ignition
\\(\bigcirc\\) b. combustion and expansion
\\(\bigcirc\\) c. air and fuel intake
\\(\bigcirc\\) d. exhaust

Explanation:

The four - stroke engine cycle has four steps: intake, compression, power (combustion and expansion), and exhaust. In the exhaust step, the products of combustion (such as \(CO_2\), \(H_2O\), and \(CO\)) are expelled from the engine. Let's analyze each option:

• Option A: Compression and ignition (compression stroke) is about compressing the air - fuel mixture, no emission of these gases occurs here.
• Option B: Combustion and expansion (power stroke) is when combustion happens, but the actual release of the exhaust gases (including \(CO_2\), \(H_2O\), \(CO\)) to the outside of the engine system occurs in the exhaust stroke.
• Option C: Air and fuel intake is just taking in the air - fuel mixture, no emission.
• Option D: In the exhaust stroke, the exhaust valve opens and the engine releases the combustion products like \(CO_2\), \(H_2O\), and \(CO\) out of the engine cylinder.

Answer:

D. Exhaust