Using numerical simulations shows that particulate trap regeneration does not occur below a certain critical inlet temperature, 679 K, for a typical diesel exhaust mass flow rate of 0.0523 kg/s. A new bypass design for particulate trap regeneration has been studied, where the exhaust flow is divided into several channels, which results in a smaller flow rate in each particulate filter. This reduces the critical inlet temperature by 20 K to 40 K, depending on the number of channels, and allows for improved regeneration efficiency with low electric energy consumption. In addition, a zero-order analytical estimate for the ignition time is also developed, given by u(ig) = 2.50/xi + ln\r(i)\ - 0.344, where uig is a dimensionless ignition time, r(i) is a reduced temperature, and depends upon feed temperature, flow rate, oxygen concentration, and initial deposit thickness. An optimal design using three bypass channels is obtained by theory and simulation. (C) 2004 American Institute of Chemical Engineers