US Patent 7886703 Variable valve mechanism of internal combustion engine

When an actuation mechanism fails to operate and thus fails to control a turning of a control shaft of a valve lift varying mechanism, a moving member is enforcedly moved to an intermediate stable position by a biasing force that is produced by combining a first type force that biases the control shaft in a direction to increase a valve lift degree of an engine valve and a second type force that biases the control shaft in a direction to reduce the valve lift degree of the engine valve. The intermediate stable position of the moving member assures an easy engine starting even in a cold engine condition.