What is the main purpose of a "variable" orifice tube in an A/C system?

The main purpose of a variable orifice tube in an A/C system is to improve low-speed cooling efficiency. This component is designed to adjust the flow of refrigerant based on the cooling demand, ensuring that adequate refrigerant is supplied when the vehicle is operating at lower speeds or under lighter cooling loads. By optimizing refrigerant flow, the orifice tube helps to maintain the necessary pressure and temperature conditions for effective cooling, particularly in situations where the air conditioning system might otherwise struggle to provide sufficient cooling capacity.

This capability is especially important in stop-and-go traffic or when the vehicle is idling, where airflow through the condenser might be reduced and cooling performance can be compromised. The variable aspect of the orifice tube allows it to respond dynamically to changing conditions, thereby enhancing overall system performance under various operational scenarios.