Method and apparatus for reducing oxides of nitrogen in the exhaust gas of an internal combustion engine

Claim 2

An engine system comprising: an internal combustion engine having a plurality of cylinders, each of which has an intake port and an exhaust port; an air intake system through which air is directed to the cylinders of the engine; an exhaust system for directing exhaust gas generated by combustion in the cylinders to the outside atmosphere; a pressurizing unit operable to compress air; and a pressure swing adsorption unit having an inlet connected to the pressurizing unit to receive compressed air therefrom, and an outlet connected to the air intake system of the engine, said pressure swing adsorption unit including an adsorbent bed cyclable between a production mode, wherein nitrogen in the air is adsorbed by the adsorbent bed at an elevated pressure to produce nitrogen-reduced air, and a regeneration mode, wherein nitrogen is desorbed from the adsorbent bed at a reduced pressure to produce nitrogen gas, said nitrogen-reduced air from the production mode of the adsorbent bed being supplied to the air intake system of the engine.

Claim 3

The engine system of claim 1 , further comprising an air filter through which air may be directed to the pressurizing unit, said air filter being operable to filter the air to remove particulates therein.

Claim 4

The engine system of claim 2 , further comprising an air dryer connected between the air filter and the pressurizing unit, said air dryer containing a desiccant for removing water from the filtered air.

Claim 5

The engine system of claim 3 , further comprising a second air filter connected between the pressure swing adsorption unit and the air intake system of the engine.

Claim 6

The engine system of claim 1 , wherein the pressurizing unit is a compressor.

Claim 7

The engine system of claim 1 , wherein the pressurizing unit is a turbocharger.

Claim 8

The engine system of claim 1 , wherein the pressurizing unit is a supercharger.

Claim 9

The engine system of claim 1 , wherein the pressure swing adsorption unit comprises a second adsorbent bed cyclable between a production mode, wherein nitrogen in the air is adsorbed by the second adsorbent bed at an elevated pressure to produce nitrogen-reduced air, and a regeneration mode, wherein nitrogen is desorbed from the second adsorbent bed at a reduced pressure to produce nitrogen gas, and wherein said nitrogen-reduced air from the production mode of the second adsorbent bed is supplied to the air intake system of the engine.

Claim 10

The engine system of claim 8 , wherein when the adsorbent bed is in the production mode, the second adsorbent bed is in the regeneration mode, and when the second adsorbent bed is in the production mode, the adsorbent bed is in the regeneration mode.

Claim 11

The engine system of claim 9 , wherein the first and second adsorbent beds are each continuously cycled between the production mode and the regeneration mode while the engine is running.

Claim 12

The engine system of claim 1 , wherein the engine further comprises fuel injectors for the cylinders, and wherein the air intake system comprises an intake manifold for supplying air to the intake ports of the cylinder, and an air header for supplying air to the fuel injectors.

Claim 13

The engine system of claim 11 , wherein the nitrogen-reduced air from the pressure swing adsorption unit is supplied to the air header.

Claim 14

The engine system of claim 11 , wherein the nitrogen-reduced air from the pressure swing adsorption unit is supplied to the intake manifold.

Claim 15

The engine system of claim 13 , wherein the nitrogen-reduced air from the pressure swing adsorption unit is also supplied to the air header.

Claim 16

The engine system of claim 1 , further comprising an exhaust gas recirculation duct connected between the exhaust system and the air intake system, said exhaust gas recirculation duct being adapted to convey exhaust gases into the air intake system for mixing with the nitrogen-reduced air from the pressure swing adsorption unit.

Claim 17

The engine system of claim 15 , further comprising a control valve disposed in the exhaust gas recirculation duct, said control valve being operable to control the flow of exhaust gas through the exhaust gas recirculation duct.

Claim 18

The engine system of claim 1 , wherein the adsorbent bed is comprised of zeolites.

Claim 19

The engine system of claim 1 , wherein the pressure swing adsorption unit further comprises three other adsorbent beds.

Claim 20

An air supply system for an internal combustion engine, said air supply system comprising: a pressurizing unit operable to compress air; an air filter through which air may be directed to the pressurizing unit, said air filter being operable to filter the air to remove particulates therein; an air dryer connected between the air filter and the pressurizing unit, said air dryer containing a desiccant for removing water from the filtered air; and a pressure swing adsorption unit having an inlet connected to the pressurizing unit to receive compressed air therefrom, and an outlet for connection to an air intake system of the engine, said pressure swing adsorption unit including an adsorbent bed cyclable between a production mode, wherein nitrogen in the air is adsorbed by the adsorbent bed at an elevated pressure to produce nitrogen-reduced air, and a regeneration mode, wherein nitrogen is desorbed from the adsorbent bed at a reduced pressure to produce nitrogen gas, said nitrogen-reduced air from the production mode of the adsorbent bed exiting the pressure swing adsorption unit through the outlet.

Claim 21

An air supply system for an internal combustion engine, said air supply system comprising: a pressurizing unit operable to compress air; an air filter through which air may be directed to the pressurizing unit, said air filter being operable to filter the air to remove particulates therein; an air dryer connected between the air filter and the pressurizing unit, said air dryer containing a desiccant for removing water from the filtered air; and a pressure swing adsorption unit having an inlet connected to the pressurizing unit to receive compressed air therefrom, and an outlet for connection to an air intake system of the engine, said pressure swing adsorption unit including an adsorbent bed cyclable between a production mode, wherein nitrogen in the air is adsorbed by the adsorbent bed at an elevated pressure to produce nitrogen-reduced air, and a regeneration mode, wherein nitrogen is desorbed from the adsorbent bed at a reduced pressure to produce nitrogen gas, said nitrogen-reduced air from the production mode of the adsorbent bed exiting the pressure swing adsorption unit through the outlet.

Claim 22

The air supply system of claim 19 , further comprising a second air filter connected to the outlet of the pressure swing adsorption unit.

Claim 23

The air supply system of claim 19 , wherein the pressurizing unit is a compressor.

Claim 24

The air supply system of claim 19 , wherein the pressurizing unit is a turbocharger.

Claim 25

The air supply system of claim 19 , wherein the pressurizing unit is a supercharger.

Claim 26

The air supply system of claim 19 , wherein the adsorbent bed is comprised of zeolites.

Claim 29

The method of claim 25 , further comprising the step of directing exhaust gas into the air intake system of the engine for mixing with the nitrogen-reduced air from the adsorption bed.

Claim 30

The method of claim 25 , wherein steps (c) through (f) are continuously repeated while the engine is running.