Draw-through sensors are typically used in naturally aspirated engines.

Draw-through sensors are typically used in naturally aspirated engines.

• A. Draw-through
• B. Mass Air
• C. Blow-through
• D. Karman vortex

Answer: (A)

The main idea here is how the air flow sensor is positioned and how air moves through it. In a draw-through setup, the air is drawn through the sensor by the engine’s vacuum as it enters the intake and moves toward the throttle and cylinders. There’s no boost pressure pushing air through the sensor, which is typical for naturally aspirated engines. This arrangement keeps the sensor in the path of the normal intake air flow and simplifies calibration because the air pressure seen by the sensor is near ambient. In contrast, a blow-through arrangement places the sensor after a compressor (like a turbocharger), so air is pushed through the sensor under boosted pressure. That requires different handling and sensor design to cope with higher pressures. The other options describe either a sensor type (Mass Air) or a different flow-measurement method (Karman vortex) that isn’t about whether the engine is naturally aspirated or boosted. That’s why the term draw-through is the best fit for naturally aspirated engines.

The main idea here is how the air flow sensor is positioned and how air moves through it. In a draw-through setup, the air is drawn through the sensor by the engine’s vacuum as it enters the intake and moves toward the throttle and cylinders. There’s no boost pressure pushing air through the sensor, which is typical for naturally aspirated engines. This arrangement keeps the sensor in the path of the normal intake air flow and simplifies calibration because the air pressure seen by the sensor is near ambient.

In contrast, a blow-through arrangement places the sensor after a compressor (like a turbocharger), so air is pushed through the sensor under boosted pressure. That requires different handling and sensor design to cope with higher pressures. The other options describe either a sensor type (Mass Air) or a different flow-measurement method (Karman vortex) that isn’t about whether the engine is naturally aspirated or boosted. That’s why the term draw-through is the best fit for naturally aspirated engines.