System and method for air flow and EGR flow estimation

• US 6,609,058 B1
• Filed: 03/30/2000
• Issued: 08/19/2003
• Est. Priority Date: 01/11/1999
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Russell, John D., Kotwicki, Allan Joseph, Gates, Freeman Carter
• Primary Examiner(s): Vo, Hieu T.
• Application Number:
  US09/539,227
• Time in Patent Office: 1,237 Days
• Field of Search: 701/104, 701/108, 123/568.11, 123/568.16, 123/568.18, 123/568.19, 123/568.21, 123/568.26, 123/568.27, 731/173, 731/182, 738/615.2, 738/616.1
• US Class Current: 701/104
• CPC Class Codes: F02D 2041/1432 the system including a filter, e.g. a low pass or high pass filter
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/182 for the control of a fuel injection device
• CPC Class Codes: F02D 41/32 of the low pressure type F02D41/3082 takes precedence
• CPC Class Codes: F02M 26/47 the characteristics being temperatures, pressures or flow rates
• CPC Class Codes: F02M 26/57 using electronic means, e.g. electromagnetic valves
• CPC Class Codes: G01F 1/34 by measuring pressure or differential pressure
• CPC Class Codes: G01F 1/36 the pressure or differential pressure being created by the use of flow constriction
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 22/02 involving measurement of pressure
• CPC Class Codes: G01F 9/001 with electric, electro-mechanic or electronic means G01F9/008 and G01F9/02 take precedence
• CPC Class Codes: G01F 9/023 with electric, electro-mechanic or electronic means
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An exhaust gas recirculation systems directs exhaust gasses from an exhaust manifold to an intake manifold of an internal combustion engine. The exhaust gasses travel from the exhaust manifold, first passing through a flow control valve and then through a measuring orifice before entering the intake manifold. Pressure upstream of the orifice is used, along with correction pressure downstream of the orifice, to measure and control exhaust gas flow. Further, manifold pressure is determined from downstream pressure and the used along with the measured exhaust gas flow to calculated a cylinder air charge amount.

Claims

1. A method for estimating engine flows, including exhaust gas flow from an engine exhaust to and engine intake wherein the flow passes through a flow control valve and then a fixed area measuring orifice and airflow into an engine cylinder, the method comprising;

determining a pressure difference across the measuring orifice;

determining a pressure downstream of the measuring orifice representative of manifold pressure;

calculating the exhaust gas flow based on said downstream pressure and said differential pressure;

determining a cylinder exhaust gas amount by filtering the calculated exhaust gas flow; and

determining a parameter related to the cylinder airflow based on said cylinder exhaust gas amount and said downstream pressure.

2. The method recited in claim 1 wherein said step of calculating the exhaust gas flow further comprises calculating the exhaust gas flow based on a product of said downstream pressure and said differential pressure.

3. The method recited in claim 1 wherein said step of calculating the exhaust gas flow further comprises calculating the exhaust gas flow based on a square root of said product of said downstream pressure and said differential pressure.