Abstract
Keywords
Charge air cooling, Downsizing, Low temperature loop, WCAC
Abstract Car makers consider downsizing to be the appropriate way to achieve greater fuel efficiency and lower emissions while guaranteeing engine power brake performance.
Cooled turbo charging appears to be key to engine downsizing, which implies a huge power rejection on charge air coolers. These however have to evolve in order to address ever more severe mechanical and thermal constraints.
Air to air charge air cooling is the rule in todays standard car. In the case of an engine downsized to meet future regulation standards, water charge air cooling appears to be a very effective solution that complies both with packaging and heat efficiency considerations.
A study was conducted on the air cooling function, with both an air to air and a water to air charge air cooler (CAC). The impact on the engine and on the charge air line was also studied. The pressure drop and the impulse behavior of charge air coolers were tested and measured. An engine test bench was used at CMT Motores Térmicos, with a fully instrumented engine (pressure, temperature ) for measuring all the physical parameters.
VALEO intercoolers (air to air and water to air) were mounted on this equipment. A methodology was designed to simulate a charge air cooler mounted onto a vehicle (coolant air profile, low temperature loop with thermal inertia). The engine behaviour was studied during transient accelerations and possible gains were discussed. Improved driveability for the end user was clearly the target.