| 摘要 |
An exhaust gas recirculating system having a plastic intake passage 4 comprises an exhaust gas recirculating valve (not shown), a cooling device 6 positioned between the valve and the intake passage 4 having mutually separated first and second passages 14, 15. The first passage 14 connects the valve to the intake passage 4 and passes through the cooling device 6, said first passage 14 having a pipe portion 17 which penetrates the plastic intake passage 4. An annular clearance is maintained between the outer surface of the first passage and the plastic intake passage wall to prevent hot exhaust gases damaging the intake passage. The cooling device 6 comprises a housing formed from two sections 11,12 held together by threaded bolts 21. Also disclosed (figure 7) is a further means of protecting a plastic intake passage from hot exhaust gases by using a bell shaped collar to maintain a clearance between a pipe - which introduces the exhaust gas through an opening into the intake passage - and the opening of a plastic intake passage. In addition chamfering the inner and outer ends of the opening creates turbulant flow which assists cooling. |
