Four valves per cylinder engine head

Abstract

An improved head assembly replacement for the Harley Davidson Motorcycle engine 20 adapted to utilize four valves per cylinder using push rods 50 without modification to the engine block, and maintaining the existing location and configuration for the mounting of the normal intake and exhaust systems. The standard rocker arms actuate the new dual intake and exhaust valves through a yoke 54 bridging each pair of valves. The exhaust valve and intake valve pairs are inclined at an included angle of 50 to 70 degrees in the plane of the engine crankshaft. The pushrods 50 remain in the standard position and the self-adjusting hydraulic tappets are retained.

Description

TECHNICAL FIELD [0001] The present invention relates to heads for gasoline internal combustion engines in general and more specifically to head conversions having four valves per cylinder with the spark plug centered between the valves and push rods communicating directly with rocker arms actuating the valves. BACKGROUND ART [0002] Previously, attempts have been made in engine modifications replacing the head with a retrofit that utilizes the existing camshaft driving pushrods, rocker arms and four valves, which are arranged in the classic “V” form of the intake and exhaust valves. In the past, for motorcycle engines having two cylinders set at a “V” have typically used, for this conversion, rockers arms having two fingers actuating each valve. This necessitates the periodic adjustment for the proper operating clearance of the space between each valve and rocker arm finger. Diesel engines with four valves per cylinder, commonly use a rocker arm having a single finger, which actuates...

AI Technical Summary

Benefits of technology

[0011] It is, there fore a primary object of the invention to employ a unique conversion head utilizing four valves with the spark plug in the center with the standard single arm rocker arm imparting equal displacements of a pair of valves through a yoke. This combination creates a near optimum configuration of the combustion chamber and allows the exhaust and intake valves to have an angular displacement between 50 to 70 degrees with no change required in the remainder of the engine.

[0013] The design of the present invention accomplishes the desired use of greater flow yielding four valves at angles allowing the spark plug location and combustion chamber to be advantageous and highly superior to the prior art.

[0014] Another object of the invention leads to higher engine speeds and greater power while using the standard intake and exhaust systems.

[0015] Still another object of the invention increases performance with less emissions as the combustion chamber s configuration is conducive for charge combustion and therefore the fuel is efficiently consumed. Further, this advantageous head system provides reliability and ease of maintenance due to the effective use of the automatically adjusting hydraulic tappets.

Problems solved by technology

While this approach is basically acceptable, there are some inefficiencies, such as restricted flow areas through valve ports which limit power at high engine speeds.

Further, the position of the spark plug is not in the optimum location which should be in the center of the combustion chamber and the shape of the combustion chamber is governed by the two valve design not resulting in the lowest possible exhaust emissions and highest combustion efficiency.

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