System and method of controlling exhaust gas recirculation

• US 6,286,489 B1
• Filed: 04/17/2000
• Issued: 09/11/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Bailey, Brett M.
• Primary Examiner(s): WOLFE JR, WILLIS RAY
• Application Number:
  US09/550,874
• Time in Patent Office: 512 Days
• Field of Search: 123/58.8, 123/568.11, 123/568.12, 123/568.17, 123/568.18, 123/568.19, 123/568.2, 123/568.21, 701/108
• US Class Current: 123/568.11
• CPC Class Codes: F02D 41/0047 Controlling exhaust gas recirculation [EGR] temperature control with cooler in recirculation circuit F02M26/33
• CPC Class Codes: F02D 41/008 Controlling each cylinder individually
• 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 26/28 with liquid-cooled heat exchangers
• CPC Class Codes: F02M 26/42 having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders
• CPC Class Codes: F02M 26/47 the characteristics being temperatures, pressures or flow rates
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An improved method and system for controlling exhaust gas recirculation on an internal combustion engine broadens the operating range. The system includes a plurality of combustion chambers, a recirculation combustion chamber, fuel delivery device, engine condition sensing device, and controller. The system measures engine condition to determine a total fuel mass to meet engine condition. The system then uses the recirculation manifold to set volume of recirculated air and adjusts fuel delivery to the recirculation manifold to set quality of the recirculated gas. The remainder of fuel is divided generally equally among the plurality of combustion chambers.

Claims

1. A method for controlling an exhaust gas recirculation system in an internal combustion engine having a plurality of combustion chambers being connectable to an exhaust system and an inlet system, at least one recirculation combustion chamber being connectable to the inlet system;

said method comprising the steps;

determining an operating condition of said engine;

determining a total mass of fuel required for said operating condition;

distributing said total mass of fuel to said plurality of combustion chambers in non-equal proportions according to said operating condition, said recirculation combustion chamber receiving a larger proportion of said total mass of fuel where said engine operating in a predetermined upper range, said recirculation combustion chamber receiving an equal proportion of said total mass of fuel where said engine operating in a predetermined middle range, said recirculation combustion chamber receiving a smaller proportion of said total mass where said engine operating in a predetermined lower range.

2. The method for controlling an exhaust gas recirculation system as recited in claim 1 wherein the step of determining said operating condition being measuring a pressure of an inlet flow.

3. The method for controlling an exhaust gas recirculation system as recited in claim 1 wherein said determining operating condition being sensing a gas temperature of a recirculation flow.

4. The method for controlling exhaust gas recirculation as recited in claim 1 further comprising the steps of:

determining a speed of an engine; and

further adjusting said mass of fuel delivered to said recirculation combustion chamber directly with said engine speed.

5. The method for controlling an exhaust gas recirculation system as recited in claim 1 further comprising the step of cooling a recirculation flow.

6. The method for controlling an exhaust gas recirculation system as recited in claim 5 wherein said step of cooling said recirculation flow is placing said recirculation flow into a heat exchange relationship with a bleed flow.

7. The method for controlling an exhaust gas recirculation system as recited in claim 6 further comprising the steps of:

increasing a pressure of said bleed flow; and

cooling said bleed flow.

8. A system for controlling exhaust gas recirculation in an internal combustion engine, said system comprising:

a plurality of combustion chambers;

an exhaust system being fluidly connectable with said combustion chambers;

an inlet system being fluidly connectable with said combustion chambers;

a recirculation combustion chamber being fluidly connectable with said inlet system;

an engine operating condition sensing device being connectable with said engine, said engine operating condition sensing being adapted to sense an engine operating condition;

a fuel delivery device, said fuel delivery device being fluidly connectable with said plurality of combustion chambers and said recirculation combustion chamber; and

a controller connected to said fuel delivery device, said controller determining a total mass of fuel for according to a sensed engine operating condition, said controller determining an equal proportion of the total mass of fuel to be delivered to each of said combustion chambers and said recirculation combustion chamber, said controller adjusting said equal proportion of said total mass of fuel to be delivered to said combustion chambers inversely with said sensed operating condition, said controller adjusting said equal proportion of said total mass of fuel to be delivered to said recirculation combustion chamber in direct relation with said sensed operating condition.

9. The system for controlling exhaust gas recirculation as recited in claim 8 wherein said inlet system includes a pressure charging system being located upstream from a connection of said inlet system with said recirculation combustion chamber.

10. The system for controlling exhaust gas recirculation as recited in claim 8 wherein said fuel delivery device being a fuel injector.

11. The system for controlling exhaust gas recirculation as recited in claim 8 wherein said engine operating condition sensing device being adapted to sense an engine load.

12. The system for controlling exhaust gas recirculation as recited in claim 11 wherein said engine load being determined by a pressure sensor being positioned in said inlet system.

13. The system for controlling exhaust gas recirculation as recited in claim 8 further comprising an exhaust gas recirculation cooling system being intermediate said recirculation manifold and said inlet system, said exhaust gas recirculation cooling system being adapted to cool a recirculation flow.

14. The system for controlling exhaust gas recirculation as recited in claim 13, said exhaust gas recirculation cooling system having a bleed conduit being connectable intermediate said inlet system and said exhaust system, a supply conduit being connectable intermediate said recirculation manifold and said inlet system, said bleed conduit being in a heat exchange relationship with said supply conduit.

15. The system for controlling exhaust gas recirculation as recited in claim 13 further comprising a control valve being positioned intermediate said inlet system and said exhaust gas recirculation cooling system, said control valve being connectable with said controller, said control valve being movable in a range from a first position and a second position, said first position fluidly connecting said recirculation combustion chamber with said inlet system, said second position preventing fluid communication between said recirculation combustion chamber and said inlet system.

16. The system for controlling exhaust gas recirculation as recited in claim 15 further comprising a temperature sensor being connected intermediate said exhaust gas recirculation cooling system and said inlet system, said sensor being connected to said controller, said sensor being adapted to measure a temperature of recirculation flow.