Catalyst Control System for Multiple Light Off Events

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Solution Overview

Problem

Existing vehicle control systems face challenges in efficiently managing catalyst light off events to maintain high conversion efficiency of the catalyst during multiple engine startups within a drive cycle, particularly when the catalyst temperature is low and ambient conditions are unfavorable.

Innovation Solution

A catalyst control system that selectively initiates multiple catalyst light off events during a drive cycle, retarding spark timing and enriching fueling when the catalyst temperature is below a predetermined threshold, and adjusts the duration of these events based on catalyst aging and ethanol content, ensuring the catalyst remains warm and efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple catalyst light off events are initiated during a drive cycle when catalyst temperature is below threshold, then catalyst conversion efficiency is improved, but fuel consumption increases

Engineering Contradiction:

Improvecatalyst conversion efficiencyVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary heating action by initiating catalyst light off events before the catalyst reaches operating temperature. The ECM detects low catalyst temperature conditions and proactively enriches the fuel mixture and retards spark timing to generate excess heat that warms the catalyst, ensuring it reaches efficient operating temperature before normal operation begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies periodic heating cycles through multiple catalyst light off events during a single drive cycle. When the catalyst temperature drops below the threshold during operation, the ECM temporarily enriches the fuel mixture and retards spark timing again to generate heat, creating periodic heating cycles that maintain catalyst temperature and conversion efficiency throughout the drive cycle.

Inventive Principle:

Principle #19Periodic action

2Temperature

If spark timing is retarded and fueling is enriched during catalyst light off events, then catalyst temperature is increased, but engine torque output decreases

Engineering Contradiction:

Improvecatalyst temperatureVSAvoidengine torque output

Core Design Contradiction:

TemperatureVSPower

Solution Approach 1:

The system applies partial enrichment and retardation only during the specific periods when catalyst light off is needed, rather than continuously. The ECM monitors catalyst temperature and only enriches the fuel mixture and retards spark timing when the catalyst temperature falls below the threshold, applying the corrective action partially and temporarily to minimize impact on engine torque while still achieving the heating objective.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach increases the catalyst's conversion efficiency throughout the drive cycle, reducing emissions while potentially increasing fuel consumption, but allows for improved engine performance and emission control.

Implementation Method 1

A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

A fuel control module richens fueling of the engine during the first CLO event of the period and richens fueling of the engine during the second CLO event of the period

Methodology Applied

Scientific EffectFuel enrichment:

Implementation Method 3

A spark control module retards spark timing of the engine during the first CLO event of the period and that retards the spark timing of the engine during the second CLO event of the period

Methodology Applied

Scientific EffectCombustion timing control: Combustion

Data Source

PatentUS10001073B2Systems and methods for multiple catalyst light off events during drive cycle

Publication Date: 2018.06.19 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A catalyst control system includes a stop and start module that, during a period that the vehicle is ON between (i) a first time when the vehicle is turned ON and (i) a second time when the vehicle is next turned OFF, selectively shuts down and starts a spark ignition engine of the vehicle. A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature, selectively initiates a second CLO event for a second engine startup during the period. A fuel control module richens fueling of the engine during the first and second CLO events of the period. A spark control module retards spark timing of the engine during the first and second CLO events of the period.