Ford Motor Company has developed its 6.6 and 7.8 litre diesel engines for use in Class 6 and 7 vehicles. All engines in these two families are turbocharged and some are after cooled, with either jacket water or air. To improve horsepower ratings, fuel economy, and emission levels, the charge air is cooled to increase its density and thus the combustion efficiency.
This paper reports the results of a joint study by Ford and Thermag Industries to optimize the air-to-air cooling system with respect to system pressure losses, thus achieving the highest possible density recovery ratio.
It is noted that the theoretical density recovery ratio can be greater than 1.0, that is, a net pressure gain can be achieved through proper conversion of velocity head to static pressure, although practically this ratio will usually be less than 1.0.