What are the desired performance targets for the charge air cooler in terms of cooling efficiency and pressure drop?

The desired performance targets for a charge air cooler (CAC) typically revolve around two key aspects: cooling efficiency and pressure drop. These targets depend on factors such as the engine's power output, operating conditions, and specific performance requirements. Here's a breakdown of each aspect:

Cooling Efficiency:

Cooling efficiency refers to the ability of the charge air cooler to reduce the temperature of the compressed intake air from the turbocharger or supercharger before it enters the engine's combustion chamber.
The desired cooling efficiency target is usually expressed as a percentage reduction in intake air temperature relative to the ambient temperature or the temperature at the turbocharger outlet.
Common targets for cooling efficiency range from 60% to 80%, meaning that the charge air cooler should cool the intake air by 60% to 80% of the temperature rise caused by compression in the turbocharger.
Higher cooling efficiency helps improve engine performance, fuel efficiency, and emissions by increasing the air density and oxygen content of the intake air, leading to more complete combustion and reduced risk of detonation (knocking).
Pressure Drop:

Pressure drop refers to the reduction in air pressure across the charge air cooler as the compressed intake air flows through the cooler's core.
The desired pressure drop target is typically specified in terms of a maximum allowable pressure drop, measured in units such as psi (pounds per square inch) or kPa (kilopascals).
Lower pressure drop is desirable as it minimizes the energy required to pressurize the intake air and ensures that the turbocharger or supercharger can maintain the desired boost pressure without excessive workload.
Common targets for pressure drop depend on the application and system design but may range from a few psi to around 2 psi (or equivalent values in kPa).
Balancing cooling efficiency with pressure drop is essential to optimize overall engine performance and efficiency. Increasing the cooling efficiency often results in a higher pressure drop, so engineers aim to achieve the desired balance for specific application requirements.
By setting appropriate targets for cooling efficiency and pressure drop, engineers can design charge air cooler systems that effectively cool the intake air while minimizing the impact on engine performance and efficiency. These targets may vary depending on factors such as the engine's power output, operating conditions, and emissions regulations.