Engine Crankcase Breathing Passage With Flow Diode

Abstract

An internal combustion engine is disclosed which includes an improved crankcase drain back system. A set of drain flow diodes are disposed in each of the drain lines to direct fluid flow in a direction from the head portion to the crankcase. Likewise, a set of breather flow diodes are disposed in the breather lines to direct fluid flow in a second direction from the cylinder portion to the head portion. The flow diodes include a series of stacked flow diode elements which allow flow in one direction, while resisting flow in the opposite direction.

Description

FIELD[0001]The present disclosure relates to flow control for crankcase draining and breathing of an internal combustion engine, and more specifically to the use of flow diodes in the crankcase drain and breather passageways for generating flow in the direction of intended oil drain back and / or direction of intended breather flow.BACKGROUND[0002]This section provides background information related to the present disclosure which is not necessarily prior art.[0003]Under certain operating conditions gases from the cylinders of an internal combustion engine get past the piston rings and leak into the engine crankcase. These blow-by gases typical include intake air, unburned fuel, exhaust gas, oil mist and / or water vapor. It is desirable to ventilate the crankcase and re-circulate the blow-by gases to the intake side of the engine for combustion to enhance performance and improve emissions.[0004]To this end, conventional engine blocks have a series of breathers that allow the blow-by ga...

AI Technical Summary

Benefits of technology

The crankcase drain back system improves oil drain back and overall lubrication and ventilation of the engine. It also reduces pressure pulsations and excitation of resonant modes of the engine. The system can be formed within existing structure and passageways of an engine block without the need for any moving parts or as a separate, formed component that can be inserted or adapted as an external passageway or piping. The system has additional benefits such as better draining of lubricant to the oil pan, reduced oil aeration, reduced oil-to-air mass fraction, reduced oil pullover, reduced oil migration, and increased power output from the engine.

Problems solved by technology

However, reciprocating engines often create a pulsating pressure differential in the crankcase which overrides the desired flow direction in the crankcase making drain back and breathing difficult to control.

Excessive oil may be retained in the valve covers and there is a highly likelihood that fine oil mist / droplets are created.

In addition to affecting drain back and breathing, conventional systems may create pressure waves in the crankcase which excite natural resonant frequencies of the engine, in the crankcase cavity or PCV system.

The interaction between the pressure waves and the engine components when driven at these resonant frequencies can reduce power output and generate unwanted noise and vibration from the engine.

These interactions will also hinder oil drain back and cause higher oil pullover into the intake region.

Images