Abstract
ABSTRACT:
For increasing the Diesel engine's power with high and medium capacity, the solution of overcharging has been developed in the last 30 years. The existing solutions of the compact turbo-blowers (turbo-chargers) domain, with high efficiency, had encouraged the engineers to extend the overcharging of the high power engines to medium power engines, and in the last years even to the small power motors.
Taking into account the characteristics of the compression ignition engine with turbo-charger functioning, some unsolved or partial solved problems appeared, as:
1. The oil film instability from the turbo-charger bearing at the engine's partial loads, which can endanger the normal functioning of the turbo-charger, especially at low speeds;
2. The existence of a critical moment, when the turbo-charger's bearings are feed with oil, at the first ignitions, when the functioning is on used oil film. In this case there is an imminent danger of gripping, especially when this period is bigger then 3 seconds and even more in summer;
3. When the engine speed decreases, the overcharging pressure has a sudden decrease, which will produce the power decreasing and the high smog concentration.
For different practical works, like compression ignition engines testing in different ways as the conditions offered by overcharging with moist air under pressure, has been conceived and achieved a original multifunctional air-hydraulic stand.
In this article are presented the main positive influences of the overcharging with moist air about: the thermal loading of the engine especially over Diesel engines of big dimentions, the moist air overcharge influence over the oxide carbon emission, the moist air overcharge influence over the oxide nitrogen emission, the moist air overcharge influence over the carbon dioxide emission, the moist air overcharge influence over the oxygen content in the burned gases.
All this influences over the burned gases composition produced by the Diesel engine will create a decrease of burned gases concentration and will lead to a more complete combustion, having in the same time the increasing of the power at additional fuel injection.