Modification of diesel engine precombustion chamber to attenuate detonation and improve combustion

摘要

The precombustion chamber of a diesel engine is modified to incorporate an acoustical attenuator therein. Since the precombustion chamber is of fixed dimensions (not changed by piston movement), the acoustic nature and modification response are very powerful, to a surprising degree. In one embodiment of this invention, the attenuator is formed by a body of attenuative material, such as sintered metal or porous ceramic, which is placed around the lower portions of the chamber in the vicinity of the connecting passages to the main combustion chamber. In another embodiment, the attenuation is achieved by means of attenuator pockets which are spaced around the precombustion chamber with communication between these passages and the chamber being provided by means of suitable orifices, these pockets having an acoustic response such as to attenuate detonation waves. In a still further embodiment of the invention, the aforementioned pockets are filled with pellets fabricated of a porous material, such as a suitable porous ceramic or metallic ceramic, which are coated with a catalytic material, such as platinum or rhodium, the pellets providing additional acoustical attenuation with the catalytic material operating to facilitate more complete combustion.