System for a virtual liquid sensor

• US 7,349,792 B2
• Filed: 05/31/2006
• Issued: 03/25/2008
• Est. Priority Date: 05/31/2006
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Durand, James C.
• Primary Examiner(s): Wolfe, Jr.; Willis R.
• Assistant Examiner(s): Hoang; Johnny H.
• Application Number:
  US11/443,058
• Publication Number:
  US 20070277792A1
• Time in Patent Office: 664 Days
• Field of Search: 701/29, 701/33, 701/45, 701/108, 123/563, 123/568.12, 602/78, 602/79, 606/052
• US Class Current: 701/108
• CPC Class Codes: F02B 29/0468 Water separation or drainage means
• CPC Class Codes: F02B 29/0493 Controlling the air charge temperature
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• 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: F02M 26/16 with EGR valves located at or near the connection to the exhaust system
• CPC Class Codes: F02M 26/46 for determining the characteristics of gases, e.g. composition
• CPC Class Codes: F02M 26/47 the characteristics being temperatures, pressures or flow rates
• CPC Class Codes: F02M 26/53 using electric actuators, e.g. solenoids
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A system for a virtual liquid sensor is disclosed including a method for operating the liquid sensor. The method includes determining a rate of generating condensation with respect to the component. The method also includes determining a rate of purging condensation with respect to the component. The method further includes determining an amount of accumulated condensation with respect to the component as a function of the rate of generating condensation and the rate of purging condensation over a given period of time.

Claims

1. A method for operating a virtual liquid level sensor with respect to an engine system component comprising:

determining a rate of generating condensation with respect to the component;

determining a rate of purging condensation with respect to the component; and

determining an amount of accumulated condensation with respect to the component as a function of the rate of generating condensation and the rate of purging condensation over a period of time.

2. The method of claim 1, wherein the rate of generating condensation is determined as a function of an amount of water vapor produced during a combustion process, an amount of exhaust gas recirculated into at least one combustion chamber, and a humidity of ambient air directed into the at least one combustion chamber.

3. The method of claim 1, wherein the rate of purging condensation is determined as a function of a flow rate of combustion air directed through the component, at least one dimension of the component, and a previously determined level of condensation within the component.

4. The method of claim 1, further including:

determining a level of condensation within the component as a function of the amount of accumulated condensation and at least one dimension of the component; and

comparing the determined level of condensation with a predetermined value.

5. The method of claim 4, further including reducing an amount of exhaust gas recirculated from at least one combustion chamber toward an inlet manifold if the determined level of condensation is greater than the predetermined value.

6. The method of claim 1, wherein the component is an air cooler configured to reduce a temperature of combustion air directed from a compressor toward at least one combustion chamber of an engine.

7. A virtual liquid sensor for an air cooler associated within an engine system having exhaust gas recirculation comprising:

a first sensor configured to produce a first signal indicative of a flow rate of combustion air directed through the air cooler;

at least one second sensor configured to produce at least one second signal indicative of at least one parameter associated with the engine system; and

a controller configured to receive the first signal and the at least one second signal and determine an amount of condensation accumulated within the air cooler as a function of the first signal and the at least one second signal.

8. The virtual liquid point sensor of claim 7, wherein the controller is further configured to:

receive at least one third signal indicative of at least one geometric dimension of the air cooler; and

determine a level of condensation within the air cooler as a function of the determined amount of condensation accumulated within the air cooler and the at least one third signal.

9. The virtual liquid sensor of claim 8, wherein the controller is further configured to receive a fourth signal indicative of a humidity of ambient air directed toward the air cooler and determine the amount of condensation accumulated within the air cooler by:

determining a rate of generating condensation within the air cooler as a function of the at least one second signal and the fourth signal;

determining a rate of purging condensation from the air cooler as a function of the first and the at least one third signal; and

determining the amount of condensation accumulated within the air cooler as a function of the rate of generating condensation and the rate of purging condensation.

10. The virtual liquid sensor of claim 7, wherein the controller is further configured to determine a purge rate of condensation with respect to the air cooler, the condensation purge rate being indicative of an amount of condensation removed from the air cooler by the flow of combustion air through the air cooler.

11. The virtual liquid sensor of claim 10, wherein the at least one second signal is a plurality of second signals and the controller is configured to determine the purge rate by:

determining a velocity of combustion air directed through the air cooler as a function of the first signal and a geometric dimension of the air cooler;

determining a level of condensation within the air cooler as a function of the amount of condensation accumulated within the air cooler and a geometric dimension of the air cooler; and

functionally relating the determined velocity and a previously determined level of condensation within the air cooler to determine the purge rate.

12. The virtual liquid sensor of claim 7, wherein the controller is further configured to determine a generation rate of condensation with respect to the air cooler, the generation rate being indicative of an amount of condensation formed within the air cooler from the flow of combustion air through the air cooler.

13. The virtual liquid sensor of claim 12, wherein the at least one second signal is a plurality of second signals and the controller is configured to determine the generation rate by:

determining an amount of water vapor within an exhaust gas produced as a by product of a combustion process as a function of at least one of the plurality of second signals;

determining an amount of exhaust gas directed through the air cooler as a function of at least one of the plurality of second signals; and

functionally relating the determined rate of water vapor within the exhaust gas, the determined amount of exhaust gas directed through the air cooler, and a relative humidity of ambient air directed through the air cooler.

14. The virtual liquid sensor of claim 7, wherein the determined amount of condensation accumulated within the air cooler is a function of a previously determined amount of condensation accumulated within the air cooler plus a rate change in condensation formed within the air cooler minus a rate change in condensation removed from the air cooler with respect to an elapsed time.

15. A method for controlling exhaust gas recirculation with respect to an engine comprising:

determining a level of liquid within a combustion air cooler as a function of at least one dimension of the combustion air cooler, at least one parameter of the engine, and a flow rate of combustion air through the combustion air cooler; and

reducing an amount of exhaust gas recirculated from downstream of the engine toward a mixer when the determined level of liquid is greater than a predetermined value.

16. The method of claim 15, wherein determining the level of liquid within the combustion air cooler includes:

determining a rate that condensation is generated within the combustion air cooler as a function of the at least one engine parameter and a value indicative of the relative humidity of ambient air;

determining a rate that condensation is removed from the combustion air cooler as a function of the at least one dimension of the combustion air cooler, the flow rate of combustion air through the combustion air cooler, and a previously determined level of liquid within the combustion air cooler; and

determining an amount of condensation accumulated within the combustion air cooler as a function of the rate that condensation is generated within the combustion air cooler and the rate that condensation is removed from the combustion air cooler.

17. The method of claim 16, wherein determining the rate that condensation is removed from the combustion air cooler further includes:

determining a mass velocity of combustion air through the combustion air cooler as a function of the mass flow rate of the combustion air and the at least one dimension of the combustion air cooler; and

accessing a multi-dimensional look-up map functionally relating mass velocities of combustion air and levels of liquid within the combustion air cooler with rates that condensation is removed from the air cooler.

18. The method of claim 16, wherein the at least one engine parameter is a plurality of engine parameters and determining the rate that condensation is generated within the combustion air cooler includes:

determining an amount of water vapor produced during a combustion process as a function of the rate of fuel delivered to the engine; and

determining an amount of exhaust gas recirculated from downstream of the engine toward the mixer as a function of at least one of the plurality of engine parameters.

19. The method of claim 16, wherein determining the level of liquid within the combustion air cooler further includes functionally relating the amount of condensation accumulated within the air cooler and at least one dimension of the combustion air cooler.

20. The method of claim 15, wherein exhaust gas is directed from downstream of the engine to the mixer via a valve, the method further including controlling the valve to reduce the amount of exhaust gas directed toward the mixer.