Active regeneration of diesel particulate filters is becoming
essential for performance longevity given the diversity of duty
cycles and engines' operating behaviors for existing and newer
engines. The Syngas containing hydrogen and carbon monoxide from
diesel fuel and air produced by the non-catalytic Syngas Generator
is potential candidate to actively enhance the regeneration
efficiency of diesel particulate filters. The Syngas is utilized to
create an exothermic condition over a pre-catalyst to the DPF to
bring exhaust gas temperature from as low as 200°C to 650°C to
enable a sustained DPF regeneration process. The Syngas is
introduced to an inlet assembly which is divided into 4 quadrants
so the full Syngas is mixing with a quarter of the exhaust flow and
regenerating one DPF quadrant at a time.
The Syngas DPF system is designed to operate seamlessly and is
transparent to the vehicle operator. A wall-flow base metal
catalyzed DPF is used to remove particulate matter from the exhaust
stream at all operating conditions. System sensors monitor the DPF
differential pressure, system temperature gradients and exhaust gas
temperature. The DPF regeneration is triggered by the time interval
between regenerations and/or sufficient elevation in the DPF
differential pressure at all exhaust gas temperatures, however, the
lowest starting exhaust temperature is determined by the
Pre-Catalyst light-off temperature and the system overall
temperature gradients. The Syngas Generator operates in two modes;
lean mode which is the "Standby" state ready to produce
Syngas on demand and the rich mode "Syngas Production" or
the regeneration mode. During the passive DPF operation, the Syngas
Generator can either be operated in a "Standby" lean mode
or off to minimize fuel consumption.
The goal of this work is to demonstrate the performance and
durability of the developed Syngas DPF system. This paper will
discuss; system optimization, integration, retrofit aspects,
emissions and temperature gradient during the regeneration process
over FTP/steady state protocols and field system performance under
usual operating conditions highlighting component durability.