The voltage value at which a zirconia oxygen sensor switches from rich to lean or from lean to rich is closely related to the sensor's ability to detect the stoichiometric air-fuel ratio.
In a typical combustion engine with an oxygen sensor, this transition point is critical for maintaining optimal performance and reducing emissions. The stoichiometric ratio, particularly in gasoline engines, is essential for achieving the best balance between power, fuel efficiency, and pollutant reduction.
After analyzing the given options:
- Option A: 0.9 V (900 mV) is too high for the switching threshold of most zirconia oxygen sensors.
- Option B: 0.25 V (250 mV) is too low for the switching threshold.
- Option D: 0.5 V (500 mV) is close but slightly higher than the typical value.
The correct value is found when the sensor accurately detects the point at which the air-fuel mixture is neither too rich nor too lean, which occurs at:
- Option C: 0.45 V (450 mV).
Thus, the answer is:
O C. 0.45 V (450 mV).
