Exhaust gas recirculation system

• US 6,009,704 A
• Filed: 07/02/1998
• Issued: 01/04/2000
• Est. Priority Date: 07/02/1998
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Feucht, Dennis D.
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): TRAN, BINH Q
• Application Number:
  US09/109,816
• Time in Patent Office: 551 Days
• Field of Search: 60/278, 60/274, 60/280, 60/311, 60/605.2
• US Class Current: 60/278
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F02M 26/06 Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
• CPC Class Codes: F02M 26/35 with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters
• CPC Class Codes: F02M 26/50 Arrangements or methods for preventing or reducing deposits, corrosion or wear caused by impurities arrangement or layout of EGR passages with means for cleaning or treating the recirculated gases F02M26/35; protection of EGR valves from damage F02M26/74

Abstract

Past exhaust emission control systems have failed to clean the exhaust gas prior to mixing with the intake air. The present exhaust emission control system removes at least a portion of the exhaust constituents from a flow of exhaust gas prior to mixing with a flow of intake air. The present exhaust emission control system includes a control system for monitoring a operating parameter of an engine. The control system interprets the operating parameter within a controller and the controller causes an exhaust valve regulator to move between an open position and a closed position. Thus, the movement of the exhaust valve regulator infinitely between the open position and the closed position defines the quantity of flow of exhaust gas to be mixed with the flow of intake air and controls the emission, especially of NOx, being emitted from the engine depending on the operating parameters of the engine.

Claims

1. An exhaust gas recirculation system being adapted for use with an engine, comprising:

at least a cylinder being positioned within said engine;

a flow of intake air entering said cylinder;

a supply of combustible fuel entering said cylinder;

a combustion process within said cylinder defining a flow of exhaust gas exiting therefrom;

an exhaust valve regulator being interposed said flow of intake air and said flow of exhaust gas, said exhaust valve regulator being movable between an open position having a flow of exhaust gas to be recirculated passing to said flow of intake air and a closed position preventing a flow of exhaust gas passing to said flow of intake air; and

a particulate trap being positioned in said flow of exhaust gas to be recirculated and all of said flow of exhaust gas to be recirculated passing through said particulate trap prior to passing to said flow of intake air.

2. The exhaust gas recirculation system of claim 1 wherein said exhaust valve regulator being movable between said open position and said closed position through an infinite number of positions.

3. The exhaust gas recirculation system of claim 1 wherein a control system operatively controls said open position and said closed position of said exhaust valve regulator.

4. The exhaust gas recirculation system of claim 3 wherein said control system includes a controller and a sensor, said sensor being positioned on said engine and monitoring an operating parameter of said engine, said operating parameter being communicated to said controller by a signal.

5. The exhaust gas recirculation system of claim 4 wherein said controller interprets said signal and moves said exhaust valve regulator to a preestablished position between said open position and said closed position.

6. The exhaust gas recirculation system of claim 3 wherein said control system includes a controller and a plurality of sensors, said plurality of sensors being positioned on said engine and each of said plurality of sensors monitoring an individual operating parameter of said engine, said individual operating parameters being communicated to said controller by an individual signal.

7. The exhaust gas recirculation system of claim 6 wherein said controller interprets said signals and moves said exhaust valve regulator to a preestablished position between said open position and said closed position.

8. The exhaust gas recirculation system of claim 1 wherein said engine includes a turbocharger being interposed said cylinder and said particulate trap.

9. The exhaust gas recirculation system of claim 1 wherein said engine includes an aftercooler being operatively attached to said engine and said flow of intake air passing through said aftercooler before entering said cylinder.

10. A method of reducing exhaust emissions from an engine, said method comprising the steps of:

passing an amount of a flow of exhaust gas through an exhaust valve regulator;

passing said said amount of said flow of exhaust gas through a particulate trap;

passing said amount of said flow of exhaust gas after passing through said particulate trap to a flow of intake air;

passing said flow of intake air and said flow of exhaust gas after passing through said particulate trap to a cylinder; and

combusting said flow of intake air and said flow of exhaust gas within said cylinder.

11. The method of reducing exhaust emissions of claim 10 wherein said step of passing said flow of intake air and said flow of exhaust gas after passing through said particulate trap to a cylinder includes said flow of intake air and said flow of exhaust gas passing through a turbocharger before passing to said cylinder.

12. The method of reducing exhaust emissions of claim 10 wherein said step of passing said flow of intake air and said flow of exhaust gas after passing through said particulate trap to a cylinder includes said flow of intake air and said flow of exhaust gas passing through an aftercooler before passing to said cylinder.

13. The method of reducing exhaust emissions of claim 10 wherein said step of passing said flow of intake air and said flow of exhaust gas after passing through said particulate trap to a cylinder includes said flow of intake air and said flow of exhaust gas passing through a turbocharger and an aftercooler before passing to said cylinder.

14. The method of reducing exhaust emissions of claim 10 wherein said step of passing said flow of exhaust gas through a particulate trap includes a control system operatively controlling a position of an exhaust valve regulator between an open position and a closed position defining a quantity of said flow of exhaust gas.

15. The method of reducing exhaust emissions of claim 14 wherein said operatively controlling said position of said exhaust valve regulator between said open position and said closed position includes sensing an operating parameter of said engine and sending a signal representing said operating parameter to a controller, said controller interpreting said signal and moving said exhaust valve regulator between said open position and said closed position.

16. The method of reducing exhaust emissions of claim 15 wherein said moving said exhaust valve regulator between said open position and said closed position includes said moving defining an infinite number of positions.

17. The method of reducing exhaust emissions of claim 14 wherein said operatively controlling said position of said exhaust valve regulator between said open position and said closed position includes sensing a plurality of operating parameters of said engine and sending a signal representing each of said operating parameters to a controller, said controller interpreting said signals and moving said exhaust valve regulator between said open position and said closed position.

18. The method of reducing exhaust emissions of claim 17 wherein said moving said exhaust valve regulator between said open position and said closed position includes said moving defining an infinite number of positions.

19. The method of reducing exhaust emissions of claim 10 wherein only said flow of exhaust gas being mixed with said flow of intake air being passed through said particulate trap.