Hydrocarbon adsorber regeneration system

1. A regeneration system comprising:

a first electronic circuit configured to monitor a temperature of a first catalyst of a catalyst assembly in an exhaust system of an engine;

a second electronic circuit configured to select an adsorber regeneration mode and generate a mode signal based on the temperature; and

a third electronic circuit configured to

determine whether the engine is deactivated based on whether fuel injection and ignition of the engine are disabled, wherein the fuel injection and the ignition of the engine are disabled when the engine is deactivated,

based on the mode signal and whether the engine is deactivated, cause the engine to be cranked to pump air into an adsorber of the catalyst assembly to regenerate the adsorber while the engine is deactivated,

operate the engine as an air pump by cranking the engine until a temperature of the adsorber is greater than a predetermined temperature and regeneration of the adsorber is complete, and

cease from operating the engine as an air pump when the temperature of the adsorber is greater than the predetermined temperature and the regeneration of the adsorber is complete.

2. The regeneration system of claim 1 , wherein the first electronic circuit is configured to estimate the temperature based on an engine speed, a flow rate, and an engine run time.

3. The regeneration system of claim 1 , further comprising a fourth electronic circuit configured to initiate at least one pumping action to pump air into an inlet of the catalyst assembly during the air pumping mode, wherein:

the at least one pumping action includes (i) rotating a crankshaft of the engine when the engine is deactivated and (ii) activating an air pump, wherein the air pump is separate from the engine and is connected to the exhaust system; and

the third electronic circuit is configured to control operation of an electric motor to

prevent the crankshaft of the engine from rotating during an engine speed maintaining mode, and

permit the crankshaft to rotate during an air pumping mode.

4. The regeneration system of claim 1 , wherein the first electronic circuit is configured to compare the temperature to a catalyst light-off temperature and generates a comparison signal,

wherein the second electronic circuit is configured to select an air pumping mode when the comparison signal indicates that the temperature of the first catalyst is greater than or equal to the catalyst light-off temperature.

5. The regeneration system of claim 1 , a fourth electronic circuit is configured to:

control position of a bypass valve of the catalyst assembly; and

close the bypass valve during regeneration of the adsorber,

wherein the fourth electronic circuit is configured to maintain the bypass valve in a closed position based on the mode signal.

6. The regeneration system of claim 1 , further comprising a fourth electronic circuit configured to:

determine whether regeneration of the adsorber is complete based on a thermal model of the adsorber and the first catalyst, wherein the thermal model comprises an engine speed, a flow rate, an engine run time and a regeneration period of the adsorber; and

generate a regeneration complete signal based on the determination of whether the regeneration of the adsorber is complete.

7. The regeneration system of claim 6 , wherein the fourth electronic circuit is configured to determine whether regeneration of the adsorber is complete based on an estimation of energy received by the adsorber and the regeneration period of the adsorber.

8. The regeneration system of claim 6 , further comprising:

a fifth electronic circuit configured to cease operating in an air pumping mode based on the mode signal; and

a sixth electronic circuit configured to adjust position of a bypass valve of the catalyst assembly to a shutdown position based on the mode signal,

wherein the second electronic circuit is configured to generate the mode signal based on the regeneration complete signal.

9. The regeneration system of claim 1 , further comprising the catalyst assembly, wherein the catalyst assembly comprises:

the first catalyst;

the adsorber upstream from the first catalyst; and

a bypass valve,

wherein flow of the exhaust through the adsorber is based on position of the bypass valve.

10. The regeneration system of claim 9 , further comprising a second catalyst downstream from the engine and upstream from the catalyst assembly, wherein the third electronic circuit is configured to:

operate in an air pumping mode to draw thermal energy from the engine and the second catalyst to heat the adsorber to at least a regeneration temperature by operating in an air pumping mode; and

activate an air pump to pump ambient air into the exhaust system upstream from the catalyst assembly during the air pumping mode.

11. The regeneration system of claim 1 , wherein the first electronic circuit is a same electronic circuit as at least one of the second electronic circuit and the third electronic circuit.

12. The regeneration system of claim 1 , wherein the adsorber releases hydrocarbons when the temperature of the adsorber is greater than the predetermined temperature, which regenerates the adsorber.

13. The regeneration system of claim 8 , wherein each of the first electronic circuit, the second electronic circuit, the third electronic circuit, the fourth electronic circuit, the fifth electronic circuit, and the sixth electronic circuit includes at least one of an electronic circuit, an application specific integrated circuit, a processor, a memory, and a combinational logic circuit.

14. A regeneration system comprising:

an engine configured to operate in an air pumping mode while deactivated, wherein fuel injection and ignition of the engine are disabled while the engine is deactivated;

a first electronic circuit configured to monitor at least a temperature of a first catalyst of a catalyst assembly in an exhaust system of the engine;

a second electronic circuit configured to select an adsorber regeneration mode and generate a mode signal based at least on the temperature;

a third electronic circuit configured to

determine whether the engine is deactivated based on whether fuel injection and ignition of the engine are disabled, wherein the fuel injection and the ignition of the engine are disabled when the engine is deactivated, and

based on the mode signal and whether the engine is deactivated, cause the engine to be cranked to pump air into an adsorber of the catalyst assembly to regenerate the adsorber while the engine is deactivated; and

a fourth circuit configured to determine whether regeneration of the adsorber is complete based on an engine speed, a flow rate, an engine run time and a regeneration period of the adsorber.