Abstract: A device for locking/unlocking rotation of an eccentric bearing interposed between a piston-pin and a connecting rod of an internal combustion engine for changing the compression ratio of the engine. The eccentric bearing has two lock holes, two guide grooves extending circumferentially from the lock holes and two colliding surfaces. The connecting rod has at least one lock-pin hole and a lock-pin is slidably inserted in the lock-pin hole. When the lock-pin is driven toward the eccentric bearing, the lock-pin can move toward the eccentric bearing and can engage the lock hole, thereby locking the rotation of the eccentric bearing. Since the colliding surfaces are provided opposed to said guide grooves, the lock-pin can reliably engage one of the lock holes without jumping the lock hole whether the eccentric bearing rotates in a normal direction or in a reverse direction. As a result, a reliable changing between a high compression ratio and a low compression ratio can be obtained.

Abstract: Auxiliary apparatus for hot-starting an internal combustion engine includes a secondary air injection nozzle opened in the intake manifold, and a heat sensitive solenoid valve to control the supply of secondary air from an air source to the nozzle. When hot-starting the engine with the engine temperature exceeding a predetermined level, the valve opens to supply a jet of air into the intake manifold through the nozzle so that a too rich mixture gas likely to be produced in the manifold is made leaner, thus reducing the output of unburned, harmful ingredients of exhaust gas from the engine as well as improving the startability of a hot engine.