Fuel controller with an adaptive adder

• US 5,464,000 A
• Filed: 10/06/1993
• Issued: 11/07/1995
• Est. Priority Date: 10/06/1993
• Status: Expired due to Term

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Kotwicki, Allan J., Pursifull, Ross D.
• Primary Examiner(s): Dolinar, Andrew M.
• Application Number:
  US08/132,419
• Time in Patent Office: 762 Days
• Field of Search: 123/674, 123/675
• US Class Current: 123/674
• CPC Class Codes: F02D 2041/1409 using at least a proportional, integral or derivative controller
• CPC Class Codes: F02D 41/1476 Biasing of the sensor
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: F02D 41/2416 Interpolation techniques
• CPC Class Codes: F02D 41/2496 the memory being part of a closed loop

Abstract

An electronic engine control system incorporates an electronic fuel controller for adaptively altering the amount of fuel delivered to an internal combustion engine. The fuel controller detects the oxygen level contained in the engine'"'"'s exhaust emissions along with the engine speed, or engine angular velocity, load and other engine operating parameters and varies the fuel delivery in accordance with the detected parameters. The change in fuel delivery is stored in a table contained in a memory. The information stored in the table is utilized by the fuel controller as an addend to a fuel delivery value calculated from the detected operating parameters.

Claims

1. The method of controlling the amount of fuel supplied to the fuel intake of an internal combustion engine, the method comprising, in combination, the steps of:

during a closed loop method of operation, when the engine is subjected to a load greater than an idling load, detecting the angular velocity of said engine and the air mass flow rate into said engine, detecting the exhaust gas composition of the combustion products exhausted by said engine, generating an air/fuel signal from said detected exhaust gas composition, comparing said air/fuel signal against a predetermined range, altering a correction term corresponding to said detected angular velocity and said air mass flow rate if said air/fuel signal is outside of said predetermined range, and storing said correction term in a memory which contains a plurality of correction terms indexed by angular velocity and mass air flow rate;

during at least said closed loop method of operation, when the engine is subjected to a load greater than an idling load, generating a nominal fuel injection pulsewidth as a function of said air/fuel signal, said detected angular velocity and said mass flow rate of air, generating a fuel correction factor corresponding to said detected angular velocity and said mass air flow rate, by retrieving one of said correction terms which corresponds to said angular velocity and mass air flow rate, and if a correction term corresponding to said angular velocity and mass air flow rate is not stored in said memory, then generating said fuel correction factor by interpolating said fuel correction factor from a correction term stored in the memory, said generated fuel correction factor related to said nominal fuel injection pulsewidth by an affine relationship; and

generating a fuel injection value which controls the amount of fuel supplied to the fuel intake of the engine by adding said correction factor to said nominal fuel injection pulsewidth.

2. An air/fuel control system for an internal combustion engine which comprises, in combination:

means for detecting the exhaust gas composition of the combustion products exhausted by said engine;

means for detecting the angular velocity of said engine and the air mass flow rate into said engine;

means for generating an air/fuel signal from said detected exhaust gas composition;

means, operable when the air mass flow rate into the engine indicates a load greater than a load at engine idle, comprising

means for comparing said air/fuel signal against a predetermined range, and altering a correction term corresponding to said detected angular velocity and air mass flow rate if said air/fuel signal is outside of said predetermined range;

means for generating a nominal fuel injection pulsewidth value as a function of said air/fuel signal, said detected angular velocity and said air mass flow rate;

means for retrieving a correction term corresponding to said detected angular velocity and said air mass flow rate and related to said nominal fuel injection pulsewidth by an affine relationship;

means for interpolating a correction term from a plurality of stored correction terms; and

means for generating a fuel injection value which controls the amount of fuel injected into an intake of the engine by adding said retrieved or interpolated correction term to said nominal fuel injection pulsewidth value.

3. An electronic engine controller for controlling the amount of fuel delivered to combustion chambers of an internal combustion engine comprising, in combination:

means for generating an exhaust gas composition signal indicative of the concentration of exhaust gas produced by said engine;

means for generating an engine speed signal indicative of the angular velocity of the engine;

means for generating a cylinder air charge value;

a p-i controller, responsive to said exhaust gas composition signal, for generating an air/fuel signal which is indicative of a quantity by which the fuel delivery rate is to be changed;

an adaptive learning module, operable when said engine controller is in at least a closed loop form of control with an engine load which is greater than an idling load, responsive to said air/fuel signal, to said engine speed signal, and to said air charge value, comprising

storage means for storing, as a function of said engine speed signal and air charge value, a plurality of adaptive correction values; and

learning means for selectively altering the adaptive correction values by comparing said air/fuel signal to an upper and a lower calibratable limit, and altering an adaptive correction value corresponding to said engine speed signal and to said air charge value if said air/fuel signal is below said lower calibratable limit or above said upper calibratable limit;

fuel injector control signal generation means, operable when said engine controller is in at least a closed loop form of control with an engine load which is greater than an idling load, comprising

means for generating a nominal fuel injection pulsewidth value as a function of the air/fuel signal, the engine speed signal and the air charge value;

means for retrieving an adaptive correction value, which corresponds to said engine speed signal and to said air charge value and for interpolating an adaptive correction value from adaptive correction values stored in said storage means if said storage means does not contain an adaptive correction value which corresponds to said engine speed signal and to said air charge value;

means for adding said adaptive correction value to said nominal fuel injection pulsewidth value, said adaptive correction value and said nominal fuel injection pulsewidth value differing by an affine relationship; and

means for generating a fuel injection pulsewidth signal which controls the fuel delivery rate into the intake of the engine as a function of the sum of said adaptive correction value and said nominal fuel injection pulsewidth value.

4. The electronic engine controller as set forth in claim 3 wherein the means for generating a cylinder air charge value comprises:

means for detecting the air mass flow rate into said engine; and

means for estimating said cylinder air charge value as a function of said detected air mass flow rate and said engine angular velocity.

5. The invention as set forth in claim 3 wherein the means for generating a fuel injection pulsewidth signal which controls the fuel delivery rate into the intake of the engine generates the fuel injection pulsewidth signal in accordance with the relationship:

##EQU17## where, t_injection corresponds to the fuel injection pulsewidth signal;

k_multiplier is a multiplicative term which is a function of the engine speed signal and at least one predetermined constant;

m_air corresponds to the air charge value;

k_compensation corresponds to the adaptive correction value;

AFR corresponds to a stoichiometric air-fuel ratio;

λ

_intended corresponds to a desired air-fuel ratio; and

k_adder is a additive term which is a function of at least a predetermined value.