SECONDARY AIR INDUCTION PASSAGE FOR VALVE OPERATING STATE VARIABLE ENGINE

PURPOSE:To make the continuation of low-speed driving performable even in case of being locked to a high-speed corresponding mode by installing an on-off valve which interrupts the interconnection of a passage in response to a means, detecting a fact that an operating state of a valve system comes to high-speed correspondence in a low-speed driving range. CONSTITUTION:When each transfer pin comes into a sticking or binding state at a high speed mode due to malfunction in a hydraulic system or nonconformity in a return spring and so on, a cam profile of a high-speed cam is set so as to make a valve operating angle relatively larger so that blow-by and spitting of intake air occur at low speed driving and thereby maintenance of this low speed driving gets difficulty. In order to maintain engine driving in a suchlike state, there is necessary to increase an air flow rate relatively. Accordingly, there is provided with an auxiliary air passage 15 to bypass a throttle valve 6, and an auxiliary air valve 14 being opened or closed in response to inlet negative pressure is installed in this passage.