Patent ID: 7779807

Claim:
An intake/exhaust valve seal structure for an internal combustion engine, comprising: an exhaust valve and at least one intake valve associated with a combustion chamber, each of which has a stem part and a non-symmetrical, sloped valve face surface; a sealing surface formed by a non-symmetrical, sloped valve seat surface provided on a ceiling of the combustion chamber for each of the exhaust and intake valves, the sealing surface formed as a sloped surface that tapers inwardly in a direction toward intake/exhaust ports of the engine; and the non-symmetrical, sloped valve face surface provided on each of the exhaust and intake valves making surface contact with the corresponding non-symmetrical, sloped valve seat surface of the combustion chamber, wherein the stem part of each of the exhaust and intake valves includes an axis, wherein each of the valves is configured such that when every cross-section of the valve which includes the axis of the stem is viewed from a direction perpendicular to the cross-section, the cross-section is seen to cut through the sloped valve face surface on opposite sides of the valve, defining a pair of straight slope lines (ls) on opposite sides of the valve, and if the straight slope lines (ls) were to extend in a direction from every position along the entire perimeter of the non-symmetrical, sloped valve face surface and in a direction that is toward the axis of the corresponding stem part, each one of the extended straight slope lines (Ls) would converge at a predetermined point located along a length of the stem part, wherein each of the extended straight slope lines (Ls) extends at an angle θ/2 with respect to the axis of the corresponding stem part, and wherein the non-symmetrical, sloped valve face surface of each of the valves is formed such that fewer than each of the extended straight slope lines (Ls) has the same length between the non-symmetrical, sloped valve face surface and the predetermined point.