Method for the detemining nox mass flow from characteristic map data with a variable air inlet and engine temperature

• US 20030159521A1
• Filed: 03/04/2003
• Published: 08/28/2003
• Est. Priority Date: 09/04/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Winkler, Klaus, Sarholz, Walter
• Granted Patent: US 6,820,461 B2
• Time in Patent Office: Days
• US Class Current: 73/861.03
• CPC Class Codes: F01N 3/20 specially adapted for catalytic conversion F01N3/22 takes precedence; Methods of operation or control of catalytic converters
• CPC Class Codes: F01N 9/00 Electrical control of exhaust gas treating apparatus monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00
• CPC Class Codes: F01P 2025/13 Ambient temperature
• CPC Class Codes: F01P 2025/40 Oil temperature
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/14 Introducing closed-loop corrections
• CPC Class Codes: F02D 41/1462 with determination means using an estimation
• CPC Class Codes: F02D 41/3029 further comprising a homogeneous charge spark-ignited mode
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for determining the NOx mass flow at the input of an NOx storage catalytic converter in the exhaust gas of an internal combustion engine from operating parameters of the internal combustion engine is introduced, characterized in that the intake air temperature and the engine oil temperature are considered in the determination.

Claims

1. Method for determining the NOx mass flow at the input of an NOx storage catalytic converter in the exhaust gas of an internal combustion engine from operating parameters of the internal combustion engine, characterized in that the intake air temperature and the engine oil temperature are considered in the determination.

2. Method of claim 1, characterized in that the NOx mass flow (msnovk) forward of the catalytic converter is computed as a product of a temperature-independent base value (mnsnovk0) and a temperature-dependent factor (exp(FNOXBAKT*delTemv).

3. Method of claim 2, characterized in that the temperature-dependent factor is proportional to a change (delTemv) of the combustion temperature as a consequence of changes of an inlet temperature quantity (Tein), combined from air temperature and engine temperature.

4. Method of claim 1, characterized in that, in the computation of the NOx mass flow (msnovk) forward of the catalytic converter, the water vapor component of the intake air is additionally considered.

5. Method of claim 1, characterized in that the computation of the NOx mass flow forward of the catalytic converter takes place in stratified operation differently than in homogeneous operation for an internal combustion engine which can be operated in a first operating mode with a layered mixture distribution in the combustion chamber (stratified operation) and in a second operating mode with a homogeneous mixture distribution in the combustion chamber (homogeneous operation).

6. Method of claim 5, characterized in that, in homogeneous operation, additionally a factor is considered for a lambda-dependent NOx formation activation.

7. Method of claim 4, characterized in that an increasing water vapor component of the intake air operates in the computation to effect a reduction of the NOx mass flow forward of the catalytic converter.

8. Electronic control arrangement for carrying out the method of the claims 1 to 7.