A system for controlling the temperature of a particulate filter coupled to an
exhaust outlet of an internal combustion engine includes a controller responsive
to volumetric flow and temperature of exhaust gas to determine a filter regeneration
parameter. In a hybrid electric-engine vehicle application, various control strategies
are implemented as a function of the regeneration parameter to control exhaust
gas temperature suitably for proper regeneration of the particulate filter. Such
strategies include shifting the duty cycle of the engine toward lower engine speed
operation along lines of constant power output, modifying the ratio of electrical
power and engine power and controlling recharging of the battery supplying electrical
energy to the vehicle's electric drive motor under vehicle deceleration conditions.
In vehicle applications including a transmission coupled directly to the engine,
shift points of the transmission are modified as a function of the regeneration
parameter to control exhaust gas temperature.
