Faculty Advisor

Sullivan, John M.


Virtually all internal combustion engines rely on a poppet valve system for the delivery and removal of gasses. This system has numerous inefficiencies. The camshaft, push rod, rocker arm, and valve spring, needed to actuate a poppet valve contribute significantly to engine noise and vibration. The poppet valve's design and shape constrain the compression ratio so that pre-ignition is minimized. The valve spring assembly limits the engine rpm. These and other inadequacies of the poppet valve system adversely affect the performance and efficiency of an internal combustion engine. An alternative cylinder head has been designed, developed, and tested in this MQP effort. It utilizes a rotary valve system. The rotary valve is a constant inertia system for a given engine rotation speed. It is capable of higher compression ratios and improved thermal efficiencies. The rotary valve system eliminates virtually all cylinder head vibrations. The rotary valves and head were designed and examined for clearance as well as fit with the use of Pro-E. The system was machined by the MQP group and performance tested in the WPI engineering experimentation laboratory. In order to document the comparison between the poppet and rotary valve systems, tests were performed on each system. The rotary valve system demonstrated significant improvements in the power required to drive the valve system. The unit had virtually no vibration due to its constant inertia and rotation speed. As a final verification of the rotary valve system the unit was run successfully using combustible fuels. The successful run of the rotary valve system was recorded by videotape.


Worcester Polytechnic Institute

Date Accepted

January 2000


Mechanical Engineering

Project Type

Major Qualifying Project


Restricted-WPI community only

Advisor Department

Mechanical Engineering