Heavy Duty Vehicles have been dealing with high under hood temperatures even before the Environmental Protection Agency mandated their antipollution requirements for October, 2002 engines and the engine manufacturers chose Exhaust Gas Recirculation (EGR) to deal with these requirements. A major consequence of the mandates was an increase of 15-30% heat addition to the vehicle cooling system due to EGR. Future antipollution mandates are increasing the heat loads to the cooling system. The industry is approaching the problem as it has in the past by increasing the size of the heat exchangers which has no effect on reducing under hood temperatures, in fact it will increase them. Under hood temperatures need to be controlled with better under hood air management systems to remove the heat from the engine compartment.

The result of this work is a unique air management system using a plenum, electrically powered and controlled blower motors, directing heated radiator airflow by ducting through the hood of the vehicle and supplying cool air to the engine compartment by cowl air induction located in front of the windshield at the rear end of the hood and vented by venturi effect. This replaces the bladed fan, shroud and fan clutch. A US patent, # 7537072, has been granted on this unique concept. Other patents are pending.

The reduction of heat generating high temperatures from the radiator to the engine compartment is about 90%. A reduction in horsepower used by removing the bladed fan, plus improved aerodynamic airflow, translates to a 7.47% fuel savings. Fan belt, fan clutch, and pulley maintenance is zero. Using multiple, individually controlled electric fans improves airflow control. This product will benefit the industry by reducing environmental damage through fuel savings, less noise with lower under hood temperatures and decreased maintenance requirement. The military applications can expect their program objectives to be exceeded since this will be applicable and vital in all military and commercial heavy duty mobile equipment.