Method and devices for the control of the air-fuel ratio of an internal combustion engine

• US 8,170,774 B2
• Filed: 02/07/2007
• Issued: 05/01/2012
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Eldor Corporation SpA
• Original Assignee: Eldor Corporation SpA
• Inventors: Forte, Pasquale, Bordegnoni, Stefano, Gelmetti, Andrea
• Primary Examiner(s): Wolfe, Jr., Willis
• Application Number:
  US12/282,955
• Publication Number:
  US 20090326786A1
• Time in Patent Office: 1,910 Days
• Field of Search: 123/406.26, 123/406.29, 123/406.3, 123/435, 123/436, 123478-480, 123/672, 123/673, 123694-696, 701101-105, 701/109, 701/111, 701/114, 701/115, 73 3501- 3506, 731/145.2, 731/145.3, 731/147.1, 731/147.2, 702/182, 702/183, 702/185
• US Class Current: 701/104
• CPC Class Codes: F02D 35/021 using an ionic current sensor
• CPC Class Codes: F02D 41/0235 in relation with the state of the exhaust gas treating apparatus control of exhaust gas treating apparatus per se F01N
• CPC Class Codes: F02D 41/1408 Dithering techniques
• CPC Class Codes: F02D 41/1458 with determination means using an estimation

Abstract

Methods and devices for controlling the normalized air-fuel ratio of an internal combustion engine, otherwise known, in technical terms, as Lambda. The present invention is based on the use of the ionization current released by a device positioned on each cylinder of the engine. This ionization current is measured by a Control Unit equipped with a low-pass filter and electronic means which implement the invention.

Claims

1. A method for determining and putting in a quantity of fuel, on the basis of predetermined sinusoidal target signal of Lambda into an internal combustion engine equipped with a plurality of cylinders, injectors, an ionization current generating device for each cylinder and a control unit suitable to determine the Lambda value in each cylinder using the ionization current, wherein said method comprises:

measurement of the Lambda values in each cylinder of said engine during an interval of time (T) (Cylinder Lambda) and supply of the signal therefore to the control unit;

calculation of the average of the Cylinder Lambda values over all the cylinders of said engine (Average Lambda) and supply of the signal therefore;

application of a low-pass filter to the Average Lambda signal (Filtered Average Lambda signal);

application of a low-pass filter to the predetermined sinusoidal target signal of Lambda (Filtered Target Lambda signal);

calculation of the difference between Filtered Average Lambda signal and Filtered Target Lambda signal (Error Lambda) and supply of the signal therefore;

calculation of the known mathematical integral of Error Lambda, multiplied by a value between 0.01 and 1 (Lambda Correction) and supply of the signal therefore;

calculation of the sum of the predetermined sinusoidal target signal of Lambda and Lambda Correction signal (Lambda to Inject signal) and supply of the signal therefore; and

determination of the quantity of fuel to put into each cylinder of said engine on the basis of Lambda to Inject signal and supply of the signal therefore to the injectors.

2. A device for determining and putting in a quantity of fuel on the basis of predetermined sinusoidal target signal of the Lambda into an internal combustion engine equipped with a plurality of cylinders, injectors, an ionisation current generating device for each cylinder and a control unit suitable to determine the Lambda value in each cylinder using the ionisation current, wherein said device comprises:

an electronic device for measuring the Lambda values in each cylinder of said engine during a determined interval of time (T) (Cylinder Lambda) and supplying the signal therefore to the control unit;

an electronic device for calculating the average of the Cylinder Lambda values over all the cylinders of said engine (Average Lambda) and supplying the signal therefore;

a low-pass filter applied to the signal supplied by the electronic device for calculating the average (Filtered Average Lambda signal);

a low-pass filter applied to the predetermined sinusoidal target signal of Lambda (Filtered Target Lambda signal);

an electronic device for calculating the difference between Filtered Average Lambda signal and Filtered Target Lambda signal (Error Lambda) and supplying the signal therefore;

an electronic device for calculating the known mathematical integral of Error Lambda multiplied by a value between 0.01 and 1 (Lambda Correction) and supplying the signal therefore;

an electronic device for calculating the sum of predetermined sinusoidal target signal of Lambda and Lambda Correction signal (Lambda to Inject signal) and supplying the signal therefore; and

an electronic device for determining the quantity of fuel to put into each cylinder of said engine on the basis of the Lambda to Inject signal furnishing the related signal to the injectors.