US 5,050,378 A · Exhaust recharging of a four cycle internal combustion engine

Abstract

In a spark ignition or compression ignition four cycle internal combustion engine, an exhaust expansion chamber is sized to produce a reflected exhaust pressure wave timed to an auxiliary reopening of the exhaust valve after the intake valve has effectively closed. The reflected exhaust pressure wave causes the re-entry into the cylinder of a quantity of intake charge (which has previously been drawn into the expansion chamber) subsequent to the effective filling of the cylinder through the intake valve, the result being a boost in cylinder charge and pressure on the compression stroke of the piston. At engine design speed, the power output of the engine is substantially improved over the power output without the boost in cylinder charge and in compression stroke pressure. The particular exhaust expansion chambers and valve re-opening timing is adaptable to single and multiple cylinder four cycle engines. With respect to multiple cylinder engines the reflected wave can be timed to feed into another cylinder exhaust valve re-opening.

Claims30

Dependent claims

In a four cycle internal combustion engine comprising at least one combustion chamber and means to expand and contract the combustion chamber, separate intake and exhaust conduit means in fluid communication with the combustion chamber, at least one intake valve in the intake conduit means and at least one exhaust valve in the exhaust conduit means, and means to open and close said valves in timed sequence with the expansion and contraction of the combustion chamber,

the improvement comprising expansion means to draw a portion of an intake charge into the exhaust conduit means, downstream reflective means in the exhaust conduit means to cause a compression wave in the exhaust gases to be reflected back upstream to the exhaust valve and timing means to open the exhaust valve when the intake valve has effectively closed and thereby permit the reflected compression wave to force the re-entry of the intake charge in the exhaust conduit means back into the combustion chamber through the open exhaust valve with the reverse flow re-entry intake charge thereby increasing the charge and pressure in the combustion chamber.

In a four cycle internal combustion engine comprising a plurality of cylinders, at least one reciprocable piston in each cylinder, intake and exhaust conduit means in fluid communication with each cylinder, at least one intake valve controlling the fluid entering each cylinder through the intake conduit means and at least one exhaust valve controlling the exhaust gases exiting each cylinder through the exhaust conduit means, and means to open and close said valves in timed sequence with the movement of the reciprocable pistons,

the improvement comprising at least one reflection chamber in said exhaust conduit means, said reflection chamber in communication with at least two cylinders, said chamber configured to cause rarefaction waves in said reflection chamber and to cause compression waves in said reflection chamber to be reflected back upstream to the exhaust valves of the two cylinders,
timing means to open the exhaust valves upon the arrival of selected reflected compression waves whereby any intake gases previously drawn into the exhaust conduit means through one exhaust valve are caused by a reflected compression wave to be forced back through the one exhaust valve into the cylinder, said reflected compression wave resulting from the exhaust blow down exiting through another exhaust valve into the reflection chamber.

Dependencies are inferred from the claim text.

Exhaust recharging of a four cycle internal combustion engine

Life of this patent

Exhaust recharging of a four cycle internal combustion engine

Life of this patent

Abstract

Claims30