To increase degree of design freedom in an EGR (exhaust gas recirculation) passage structure.
An EGR passage structure includes: an in-head EGR passage 40 penetrating from an exhaust side sidewall 8 to an air intake side sidewall 7; exhaust side EGR passages 32, 35 serving for communication between an exhaust pipe 27 and the in-head EGR passage; and an air intake side EGR passage 45 serving for communication between an air intake pipe 27 and the in-head EGR passage. The in-head EGR passage includes: an exhaust side portion 41 linearly extending from the exhaust side sidewall; and an air intake side portion 42 bending from an inner end of the exhaust side portion and linearly extending to the air intake side sidewall. The exhaust side portion inclines upward in an axial direction of a cylinder toward the exhaust side sidewall from a bent part 43 formed at a boundary between the exhaust side portion and the air intake side portion, and a cooling water passage 50 formed in a cylinder head 4 is arranged below the air intake side portion so as to extend along the air intake side portion while being arranged with a space from the exhaust side portion.
HIRABAYASHI TAKEHIRO
ICHINOMIYA MITSURU
| JP2002004953A | 2002-01-09 | |||
| JP2007224784A | 2007-09-06 | |||
| JPS6444344U | 1989-03-16 |