Engine shutoff profile for hybrid vehicle gasoline particulate filter regeneration

1 . A hybrid electric vehicle (HEV), comprising:

an internal combustion engine;

one or more electric traction motors configured to provide drive torque to one or more vehicle axles;

a motor/generator configured to drive the internal combustion engine or be driven by the internal combustion engine to generate electricity to charge a high voltage battery and/or drive the one or more electric traction motors;

an exhaust aftertreatment system having a gasoline particulate filter (GPF); and

a control system including a controller for monitoring and performing a regeneration operation of the GPF, wherein the controller is programmed to:

determine the GPF needs to be regenerated;

determine if a temperature of the GPF meets or exceeds a predetermined threshold indicating a GPF regeneration can occur; and

upon an engine shutdown event, if the temperature meets or exceeds the predetermined threshold, gradually spin down a speed of the internal combustion engine in fuel shut-off to generate a flow of air to the GPF to initiate a GPF regeneration.

2 . The HEV of claim 1 , wherein the controller is further programmed to monitor a soot accumulation of the GPF.

3 . The HEV of claim 2 , wherein the controller is further programmed to determine if the soot accumulation meets or exceeds a predetermined threshold indicating the GPF needs to be regenerated.

4 . The HEV of claim 1 , wherein the controller is further programmed to gradually spin down the internal combustion engine according to a coast-down shutdown profile.

5 . The HEV of claim 1 , wherein if the GPF temperature does not meet or exceed the predetermined threshold, the controller is further programmed to shut off the internal combustion engine without the gradual spin down.

6 . The HEV of claim 1 , further comprising a crankshaft rotatably coupled between the engine and the motor/generator,

wherein the motor/generator is utilized to rotate the crankshaft to gradually spin down the internal combustion engine.

7 . The HEV of claim 1 , wherein during the GPF regeneration, the controller is further programmed to perform a closed loop GPF control to monitor and meter the flow of air to the GPF.

8 . The HEV of claim 1 , wherein the controller is further programmed to:

determine the GPF regeneration is complete; and

return the HEV to a normal operation by turning the engine off or ceasing the fuel shut-off.

9 . The HEV of claim 1 , wherein the HEV is a series hybrid electric vehicle.

10 . A method of operating a hybrid electric vehicle (HEV) having one or more electric traction motors configured to provide drive torque to one or more vehicle axles, an internal combustion engine, a motor/generator configured to drive the internal combustion engine or be driven by the internal combustion engine to generate electricity to charge a high voltage battery and/or drive one or more electric traction motors, and an exhaust aftertreatment system having a gasoline particulate filter (GPF), the method comprising:

determining, by a controller having one or more processors, if the GPF needs to be regenerated;

determining, by the controller, if a temperature of the GPF meets or exceeds a predetermined threshold indicating a GPF regeneration can occur; and

upon an engine shutdown event, if the temperature meets or exceeds the predetermined threshold, gradually spinning down a speed of the internal combustion engine in fuel shut-off to generate a flow of air to the GPF to initiate a GPF regeneration.

11 . The method of claim 10 , further comprising monitoring, by the controller, a soot accumulation of the GPF.

12 . The method of claim 11 , further comprising determining, by the controller, if the soot accumulation meets or exceeds a predetermined threshold indicating the GPF needs to be regenerated.

13 . The method of claim 10 , further comprising gradually spinning down the internal combustion engine, by the controller and the motor/generator, according to a coast-down shutdown profile.

14 . The method of claim 10 , further comprising, if the GPF temperature does not meet or exceed the predetermined threshold, shutting off the internal combustion engine without the gradual spin down.

15 . The method of claim 10 , wherein the HEV further includes a crankshaft rotatably coupled between the engine and the motor/generator, wherein the motor/generator is utilized to rotate the crankshaft to gradually spin down the internal combustion engine.

16 . The method of claim 10 , further comprising, during the GPF regeneration, performing, by the controller, a closed loop GPF control to monitor and meter the flow of air to the GPF.

17 . The method of claim 10 , further comprising:

determining, by the controller, the GPF regeneration is complete; and

returning, by the controller, the HEV to a normal operation by turning the engine off or ceasing the fuel shut-off.

18 . The method of claim 10 , wherein the HEV is a series hybrid electric vehicle.

19 . The HEV of claim 1 , wherein when gradually spinning down the speed of the internal combustion engine, the controller is programmed to utilize the motor/generator to electrically motor the internal combustion engine without fueling, according to a pre-defined coast-down profile.