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Difficulty: MediumFuel and Air Intake Systems

In a standard gasoline engine, what does the ideal stoichiometric air-fuel ratio of 14.7:114.7:1 represent?

  1. A
    14.7 parts of fuel to 1 part of air by weight
  2. 14.7 parts of air to 1 part of fuel by weightAnswer
  3. C
    14.7 parts of air to 1 part of fuel by liquid volume
  4. D
    14.7 intake valve cycles for every 1 power stroke

Answer

14.7 parts of air to 1 part of fuel by weight
The stoichiometric air-fuel ratio for standard gasoline engines is 14.7:114.7:1 by mass (weight). This means that for every 1 unit of fuel mass injected, exactly 14.7 units of air mass are required to achieve chemically complete combustion with minimal emissions.

Step-by-Step Solution

1
Identify the standard baseline stoichiometric ratio for automotive gasoline combustion.
The stoichiometric air-fuel ratio is defined as 14.7:114.7:1.
This specific ratio provides the exact chemical balance of oxygen required to burn all gasoline hydrocarbons completely.
2
Determine the physical units and component order of the ratio.
The ratio represents 14.7 units of air mass for every 1 unit of fuel mass.
Because air is much less dense than gasoline, 14.7 parts of air by weight are required to consume 1 part of fuel by weight.

Key Concept

Stoichiometric Air-Fuel Ratio
Estimated Time:45s
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Topics

Fuel and Air Intake Systems

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