The possibility of non-volatile particle agglomeration in engine exhaust was experimentally examined in a Euro VI heavy duty engine using a variable cross section agglomeration pipe, insulated and double walled for minimal thermophoresis. The agglomeration pipe was located between the turbocharger and the exhaust treatment devices. Sampling was made across the pipe and along the centre-line of the agglomeration pipe. The performance of the agglomeration pipe was compared with an equivalent insulated straight pipe. The non-volatile total particle number and size distribution were investigated. Particle number measurements were conducted according to the guidelines from the Particle Measurement Programme. The Engine was fuelled with commercially available low sulphur S10 diesel. Experiments conducted in heavy duty engine relevant operating points were done to sweep the effect of (i) Mass flow rate in the exhaust (ii) Temperature in the exhaust and (iii) Engine speed and thus exhaust pressure pulsation frequencies in the exhaust. The test matrix included eleven operating points at steady-state. The results show that, using the agglomeration pipe, neither significant non-volatile particle reduction nor noticeable change in particle size distribution could be proven. In the current study, nucleation of non-volatile particles could not be observed along the straight pipe. Furthermore, it was found that the variable cross-section agglomeration pipe and straight pipe showed similar results in the total particle number and particle size distribution with respect to non-volatile particles.
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