Exhaust gas recirculation method for an internal combustion engine

• US 6,038,860 A
• Filed: 08/12/1999
• Issued: 03/21/2000
• Est. Priority Date: 03/31/1997
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Bailey, Brett M.
• Primary Examiner(s): KOCZO JR, MICHAEL
• Application Number:
  US09/372,866
• Time in Patent Office: 222 Days
• Field of Search: 60/605.2, 60/606
• US Class Current: 60/605.2
• CPC Class Codes: F02B 29/0425 Air cooled heat exchangers
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02B 37/10 at least one pump being alternatively or simultaneously driven by exhaust and other drive, e.g. by pressurised fluid from a reservoir or an engine-driven pump
• CPC Class Codes: F02B 37/168 into the exhaust conduit F02B37/166 takes precedence
• 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 26/10 having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
• CPC Class Codes: F02M 26/19 Means for improving the mixing of air and recirculated exhaust gases, e.g. venturis or multiple openings to the intake system
• CPC Class Codes: F02M 26/27 with air-cooled heat exchangers
• 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: Y02T 10/12 Improving ICE efficiencies

Abstract

A system and method for recirculating exhaust gas in a turbocharged internal combustion engine is disclosed. The disclosed method comprises the steps of: (a) recirculating a selected volume of exhaust gas from the exhaust manifold to the intake manifold via a recirculation conduit; (b) diverting a flow of cool intake air to bypass the engine via a bypass conduit; and (c) cooling the recirculating exhaust gas in the recirculation conduit using the flow of diverted intake air.

Claims

1. A method of recirculating exhaust gas in an internal combustion engine, said engine having an intake circuit including an intake air pressurizing device, an intake manifold, and an exhaust manifold, the method comprising the steps of:

(a) recirculating a selected volume of exhaust gas to said intake manifold via a recirculation conduit;

(b) diverting a flow of intake air from said intake circuit via a bypass conduit; and

(c) cooling said recirculated exhaust gas in said recirculation conduit using said flow of diverted intake air.

2. The method of recirculating exhaust gas as set forth in claim 1 further comprising the step of heating said intake air in said bypass conduit using said recirculated exhaust gas, the step of heating said intake air being concurrent with the step of cooling said recirculated exhaust gas.

3. The method of recirculating exhaust gas as set forth in claim 2 wherein said air intake pressurizing device includes a gas driven turbine and a compressor, said method further includes the step of driving said gas driven turbine with any exhaust gas remaining in said exhaust manifold together with said heated intake air from said air intake bypass conduit which in turn drives said compressor thereby pressurizing said intake air in said intake circuit.

4. The method of recirculating exhaust gas as set forth in claim 3 further comprising the step of cooling said compressed intake air in said intake circuit prior to diverting said flow of intake air from said intake circuit via said bypass conduit.

5. The method of recirculating exhaust gas as set forth in claim 1 further comprising the step of cleansing said recirculated exhaust gas prior to said cooling step.

6. The method of recirculating exhaust gas as set forth in claim 1 further comprising the step of measuring the mass flow of said compressed intake air not diverted and controlling a volume of intake air diverted and volume of exhaust gas recirculated in response thereto.

7. The method of recirculating exhaust gas as set forth in claim 1 further comprising the step of measuring the temperature of said cooled recirculated exhaust gas and controlling a volume of intake air diverted and volume of exhaust gas recirculated in response thereto.