Vehicles, Diesel Particulate Filters Used In Exhaust Cooler

At present, bag filter technology used in the field of diesel bus exhaust gas particulates control is stepping into a practical application stage. The reduction of the engine exhaust gas temperature is one of the key points of this technology, which will influence the safe operation of the entire filter system. Therefore, this paper is aimed to deal with the realization of this technology and a series of projective jobs are done as follows:1. A first explorative research of the water-cooling method for the reduction of the engine exhaust gas temperature has been made, including work on the water-cooling cooler design and development of a cooler calculation program, on which a series of computations are based. The calculation results are composed of influences of the variations of structural factors on the design parameters and the cooling capability of a cooler are analyzed with the relative curve diagrams. It can be used as a guidance for later cooler design.2. A laboratory-simulation experiment on the water-cooling cooler is done to test that if the cooler's capability could meet the demand of the practical work. The test results show that the cooler designed in this paper has excellent characteristics to satisfy all the demands expected, which will provide a powerful evidence for such coolers to be employed in the future application of the bag filter system.3. After a review of the design and on-road test on the original forced air cooling cooler, two new schemes, A and B- type natural wind cooling coolers, whose heat transfer tubes are of cheaper bare ones are developed. Compared with the forecd air-cooling method, natural wind cooling method can reduce the electricity energy's consumption. In addition, some considerations on the mechanical connection between the cooler with the engine and the bag filter should be noticed during the course of cooler structure design.4. On-road experiments are carried out with these new coolers respectively in summer and winter. After an investigation of the bus route, Route 7 bus ofJiaozhou city and Route 212 and Route 317 buses in Qingdao are chosen to be the test buses. The cooling capability contrast test of A1- and A2-type coolers are done on Route 7 bus and the results show that the A2-type is a better one. Later tests on Route 212 bus were done with the A2-type cooler and the Route 317 bus with the B-type one. The on-road experiments results show that those coolers are able to meet the demand of the working temperature for the filter system and guarantee the safety of the bag filter.