Motor de combustão interna, veículo, embarcação marítima e método de suprimento de ar secundário pra motor de combustão interna

摘要

An internal combustion engine is capable of improving cleaning efficiency by preventing an increase in the temperature of the exhaust gas to lessen the deterioration of the catalyst. The internal combustion engine 1 includes a convergent section 32, a divergent section 33, and a branch section 21. The branch section 21 branches a shock wave 35, propagating in a downstream direction at a higher velocity than exhaust gas 36 flowing into an exhaust path 16 from a combustion chamber 10 when an exhaust valve 9 is opened, from a portion of the exhaust path 16 which is upstream with respect to the divergent section 33, and propagates the shock wave 35 back to the exhaust path 16. The exhaust gas 36 is caused to pass the convergent section 32 and to collide against the shock wave 35 between the branch section 21 and the divergent section 33, thus to increase the pressure of the exhaust gas 36 in the convergent section 32. Such exhaust gas 36 is caused to pass the divergent section 33 to generate a new shock wave 35b and thus to decrease the temperature of the exhaust gas. A catalyst 41 of an exhaust cleaning device 40 is provided in a portion of the exhaust path 16 which is downstream with respect to the divergent section 33.