Engine Power Limiting for Cold-Start Exhaust Emission Control

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Solution Overview

Problem

Existing methods for heating exhaust aftertreatment devices in internal combustion engines are insufficient to ensure immediate compliance with tightening pollutant emission regulations, particularly during cold starts, leading to potential violations of emission limits.

Innovation Solution

Implementing a method to limit the power output of the combustion engine when environmental emissions exceed predefined thresholds, accompanied by power-neutral adjustments and warning messages to prevent excessive emissions, and adjusting these thresholds based on travel distance to ensure compliance with legal emission limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the combustion engine operates with high power output immediately after cold start, then the vehicle can switch to driving mode and provide good driving performance, but the exhaust aftertreatment devices cannot reach light-off temperature quickly enough, causing emission limits to be exceeded

Engineering Contradiction:

Improveengine power outputVSAvoidexhaust emissions

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The control device performs preliminary actions by detecting cold start conditions and proactively limiting engine power output before the exhaust aftertreatment devices reach light-off temperature. This preventive measure ensures emissions remain below limits during the warm-up phase, avoiding the need for corrective actions later.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts engine power output based on real-time conditions. The control device continuously monitors exhaust aftertreatment device temperatures and modifies engine operation accordingly, allowing full power when temperatures are sufficient and limiting power when they are not, thus adapting to changing thermal states.

Inventive Principle:

Principle #15Dynamics

2Temperature

If heating devices or in-engine measures are used to rapidly heat exhaust aftertreatment devices, then the light-off temperature is reached faster, but these measures alone are insufficient to guarantee immediate compliance with tightening emission regulations during cold starts

Engineering Contradiction:

Improveexhaust aftertreatment device temperatureVSAvoidexhaust emissions

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The control device implements a feedback mechanism by continuously detecting exhaust aftertreatment device temperatures and comparing them against light-off temperature thresholds. Based on this feedback, the system automatically adjusts engine power output to ensure emissions remain compliant, creating a closed-loop control system that responds to actual thermal conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device acts as an intermediary between the driver's power demands and the engine's actual output. It mediates by limiting power delivery when exhaust aftertreatment devices are cold, effectively decoupling driver intent from engine execution to prioritize emission compliance over immediate power availability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the engine power output is limited to reduce emissions, then emission compliance is improved, but the driver experiences inconvenience due to reduced vehicle performance

Engineering Contradiction:

Improveexhaust emissionsVSAvoiddriver convenience

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The power limitation is applied periodically or temporarily only during the cold start warm-up phase when exhaust aftertreatment devices are below light-off temperature. Once the devices reach sufficient temperature, the system automatically transitions to normal operation, allowing full power availability. This time-limited approach minimizes driver inconvenience while ensuring emission compliance during the critical warm-up period.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12480454B2Operation of a motor vehicle as a function of exhaust emissions

Publication Date: 2025.11.25 VOLKSWAGEN AG

AI summary

A method for operating a motor vehicle with an internal combustion engine, comprising a combustion engine and an exhaust line with an exhaust aftertreatment system. At least one environmental emission of an exhaust component or multiple exhaust components, contained in the exhaust gas generated by the combustion engine, is determined. If a limitation threshold value for the environmental emission of the exhaust component or at least one of the exhaust components is exceeded, the operation of the combustion engine is limited with respect to the deliverable power. If a warning threshold value for the environmental emission of the exhaust component or at least one of the exhaust components, which is lower than the limitation threshold value, is exceeded, a warning message is triggered and/or the operation of the internal combustion engine is adapted in a power-neutral manner such that the environmental emission of the exhaust component is reduced.