Abstract
A new type valve system using a conical spring and an permanent-electromagnetic actuator was developed. The system uses a conical spring whose spring constant is low in small valve displacement, but increases with the displacement of the valve due to its nonlinear property. The system has a permanent-electromagnet which compresses the valve spring under electromagnetic control. The valve system is used without electric current in low cam speeds. Therefore, driving energy is small in low cam speeds because of spring constant being small. However, the jump and bounce phenomena occur in the high-speed cam rotation region. Those are suppressed by using a permanent-electromagnetic actuator that consists of two permanent magnets and an electromagnet. The actuator strengthens the restoration force of the spring by the electromagnetic repulsion force, and controls the jump phenomenon. Both analytical and experimental checks have been made for the proposed system. It was confirmed that, by using the system with the permanent-electromagnetic actuator, the jump and bounce phenomena were suppressed, and driving torques were also decreased.