US 8,412,437 B2Granted

Method and device for operating an internal combustion engine

AssigneeContinental Automotive GmbH

InventorsThomas Burkhardt, Jürgen Dingl, Andreas Hofmann

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Abstract

Actual values of a load variable are detected by a sensor during active model trimming under different valve pressure conditions, and a model of estimated values is created. Trimming values of a model parameter are determined depending on detected and modeled values such that when the model parameter is trimmed, the modeled values approximate the detected values. A function is determined depending on the different pressure conditions and approximated to the trimming values. At different pressure conditions first lambda control values are detected. A first controller value fitted function is determined depending on the pressure conditions and approximated. When the model trimming mode is not active, second lambda control values are detected at different pressure conditions. A second controller value fitted function is determined depending on the pressure conditions and is approximated. An error of the intake system is detected depending on the fitted functions.

Claims20

Dependent claims

A method for operating an internal combustion engine with an intake system and an exhaust gas system, which communicate with a combustion chamber of the internal combustion engine as a function of the switching position of a gas inlet valve or gas outlet valve, the intake system has at least an intake manifold and a throttle valve and a load sensor and the exhaust gas system has at least a lambda probe,

the method comprising the steps of:
when intake manifold model trimming is active:
detecting actual values of a load variable by means of the load sensor at different stationary throttle valve pressure ratios, which are representative of a difference between an intake manifold pressure upstream of the throttle valve and downstream of the throttle valve and estimated values of the load variable are also modeled based on an intake manifold model,
determining trimming values of at least one model parameter of the intake manifold model as a function of the detected actual values and the modeled estimated values of the load variable in such a manner that when the corresponding model parameter is trimmed as a function of the trimming values the modeled estimated values of the load variable approximate to the corresponding detected actual values of the load variable,
determining a trimming value best-fit function as a function of the different throttle valve pressure ratios and is approximated by the trimming values,
detecting first controller values of first controller deflections of a lambda controller at different stationary throttle valve pressure ratios, and
determining a first controller value best-fit function as a function of the throttle valve pressure ratios, which is approximated by the first controller values,
when intake manifold model trimming is inactive:
detecting second controller values of second controller deflections of the lambda controller at different stationary throttle valve pressure ratios, and
determining a second controller value best-fit function as a function of the throttle valve pressure ratios, which is approximated by the second controller values, and
identifying an error in the intake system as a function of the best-fit functions.

8 more elements

A device for operating an internal combustion engine, comprising an intake system and an exhaust gas system, which communicate with a combustion chamber of the internal combustion engine as a function of the switching position of a gas inlet valve or a gas outlet valve (13), the intake system comprising at least an intake manifold and a throttle valve and a load sensor and the exhaust gas system comprising at least a lambda probe, the device being configured when intake manifold model trimming is active:

to detect actual values of a load variable by means of the load sensor at different stationary throttle valve pressure ratios, which are representative of a difference between an intake manifold pressure upstream of the throttle valve and downstream of the throttle valve and to model estimated values based on an intake manifold model;
to determine trimming values of at least one model parameter of the intake manifold model as a function of the detected actual values and the modeled estimated values of the load variable in such a manner that when the corresponding model parameter is trimmed as a function of the trimming values the modeled estimated values of the load variable approximate to the corresponding detected actual values of the load variable,
to determine a trimming value best-fit function as a function of the different throttle valve pressure ratios which is approximated by the trimming values,
to detect first controller values of first controller deflections of a lambda controller at different stationary throttle valve pressure ratios, and
to determine a first controller value best-fit function as a function of the throttle valve pressure ratios, which is approximated by the first controller values,
when intake manifold model trimming is inactive:
to detect second controller values of second controller deflections of the lambda controller at different stationary throttle valve pressure ratios, and
to determine a second controller value best-fit function as a function of the throttle valve pressure ratios, which is approximated by the second controller values, and the device being further configured
to identify an error in the intake system as a function of the best-fit functions.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/601,213Filed 20 May 2008
Priority: DE 10 2007 023 85023 May 2007
Published: US 2010/0185379 A122 Jul 2010
Granted: 2 Apr 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

F02D 41/222
Safety or indicating devices for abnormal conditions: relating to the failure of sensors or parameter detection devices
F02D 41/1495
Details: detection of abnormalities in the air/fuel ratio feedback system
F02D 41/18
Circuit arrangements for generating control signals: by measuring intake air flow
F02D 41/221
Safety or indicating devices for abnormal conditions: relating to the failure of actuators or electrically driven elements