Stereo lambda control

• US 5,267,548 A
• Filed: 02/04/1991
• Issued: 12/07/1993
• Est. Priority Date: 08/04/1988
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schneider, Gerhard, Rosenzopf, Gunter, Steinbrenner, Ulrich, Wild, Ernst
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US07/646,607
• Time in Patent Office: 1,037 Days
• Field of Search: 123/520, 123/691, 123/692, 123/698
• US Class Current: 123/692
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/1443 with one sensor per cylinder or group of cylinders

Abstract

In the method for the adapted precontrol and feedback control of the air/fuel mixtures to be supplied to the two fuel-metering devices of an internal combustion engine, which has two separate exhaust-gas channels with a lambda probe and a catalytic converter in each channel, a common value of the precontrol manipulated variable and a common lambda desired value are determined for both fuel-metering devices. On the other hand, values of a control manipulated variable are determined separately for each fuel-metering device and values of precontrol adaptation variables, which are dependent upon the values of the control manipulated value, are determined and are superposed separately one after the other on the common precontrol value. This method makes it possible to manage with a single device for both cylinder banks which are to be operated in a stereo lambda control.

Claims

1. A method of adaptive precontrol and feedback control of the air/fuel mixtures by means of two fuel-metering devices of an engine having two separate exhaust-gas channels, each of the channels having a lambda probe and a catalyzer, the method comprising the steps of:

detecting a common load signal for the two fuel-metering devices;

determining a precontrol manipulated variable (TL * π

Fi) common to both of said fuel-metering devices and determining a common lambda desired value (λ

_des);

separately determining first values of a lambda feedback control manipulated variable for each fuel-metering device;

separately determining second value of precontrol manipulated variables dependent upon said first values;

separately determining third values of precontrol adaptive variables dependent upon said second values;

separately superposing said first values, said second values and then said third values on the common precontrol manipulated variable (TL * π

Fi);

determining a common tank-venting adaptation value from feedback control factors (FR1, FR2) specified for one of the two fuel-metering devices;

using said common tank-venting adaptation value for both of said fuel-metering devices with the precontrol adaptation taking place separately from said tank-venting adaptation; and

,

then, when a tank-venting adaptation takes place, correcting a feedback control factor (FR1, FR2) in a manner which leaves the lambda corrected injection time (TIV) unchanged.

2. The method of claim 1, wherein:

then, when the determination of the tank-venting adaptation value for the first fuel-metering device is no longer possible because of a defect, said tank-venting adaptation value is determined from the feedback control manipulated variable formed for the second fuel-metering device and is used for both fuel-metering devices in common.

3. An arrangement for adaptive precontrol and feedback control of the air/fuel mixtures by means of two fuel-metering devices of an internal combustion engine having two separate exhaust-gas channels, each of said channels having a lambda probe and a catalyzer, the arrangement comprising:

means for detecting a common load signal (TL) for both fuel-metering devices;

means for determining a common precontrol manipulated variable (TL * π

Fi) for both fuel-metering devices and for determining a common lambda value (λ

_des);

means for separately determining first values of a lambda feedback control manipulated variable for each fuel-metering device and for separately determining second value of precontrol adaptation variables, dependent on said first values, and for separately determining third values of precontrol adaptation variables dependent on said second values, and for separately and superposing said first values, said second values and then said third values on said common precontrol manipulated variable (TL * π

Fi);

means for forming a common tank-venting adaptation value for both of said fuel-metering devices, said common tank-venting value being determined from said feedback control manipulated variable determined for one of the two fuel-metering devices;

means for ensuring that precontrol adaptation and tank-venting adaptation do not take place simultaneously; and

,

means for correcting a feedback control factor (FR1, FR2) in a manner which leaves the lambda corrected injection time (TIV) unchanged when a tank-venting adaptation takes place.