To provide an internal combustion engine capable of efficiently creating reformed gas with appropriate supply quantity of fuel while performing lean operation.

This internal combustion engine is provided with at lease one first combustion pattern cylinder 1a-1c performing first combustion pattern, at lease one second combustion pattern cylinder 1d performing second combustion pattern, an exhaust gas route 3 provided with an exhaust manifold 3A collecting exhaust gas from the first and the second combustion pattern cylinders 1a-1d and an exhaust gas passage 3B discharging exhaust gas to outside via the exhaust manifold 3A, an exhaust gas branch flow route 13 branching at least part of exhaust gas from the second combustion pattern cylinder 1d out of a branch passage 3A4 of the exhaust manifold 3A, a reformer 12 arranged on the exhaust gas route 3 and communicating to the exhaust gas branch route 13 and creating reformed gas from exhaust gas and fuel, a reformed gas introduction route 14 introducing reformed gas to the intake air route 2, and a control device 4 performing lean combustion in the first combustion pattern cylinders 1a-1c and rich combustion in the second combustion pattern cylinder 1d.

COPYRIGHT: (C)2006,JPO&NCIPI