Hybrid Engine Control for Catalyst Temperature Management

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Solution Overview

Problem

In hybrid vehicles, existing engine control systems face inefficiencies in catalyst temperature regulation and engine startup management, leading to suboptimal fuel economy and emission control, particularly when the catalyst temperature falls below the light-off temperature and the electric motor can produce sufficient torque.

Innovation Solution

An engine control system comprising a temperature control module for regulating an electrically heated catalyst and an engine disabling module that selectively starts or shuts down the engine based on catalyst temperature and torque output, ensuring the catalyst remains above the light-off temperature only when necessary, and coordinates engine and electric motor torque outputs to achieve desired vehicle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine is started up to warm the catalyst when the catalyst temperature is below the light-off temperature, then the catalyst conversion efficiency is improved, but the fuel consumption increases due to unnecessary engine startups

Engineering Contradiction:

Improvecatalyst conversion efficiencyVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system monitors catalyst temperature as a key parameter and only initiates engine startup when the temperature falls below the light-off threshold. This parameter-based control ensures the catalyst operates efficiently while avoiding unnecessary engine cycles that would consume fuel, thus resolving the contradiction between maintaining conversion efficiency and minimizing energy use.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system continuously monitors catalyst temperature and uses this feedback to make intelligent decisions about engine startup. When the temperature is above the light-off temperature, the engine remains off; when it drops below, the engine starts to warm the catalyst. This feedback mechanism eliminates unnecessary startups and optimizes the balance between catalyst performance and fuel consumption.

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If the engine is kept shut down to minimize fuel consumption, then the fuel economy is improved, but the catalyst temperature drops below the light-off temperature reducing emission control effectiveness

Engineering Contradiction:

Improvefuel economyVSAvoidemission control effectiveness

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The system maintains catalyst temperature above the light-off temperature during engine operation, and only allows the engine to shut down when this temperature threshold is maintained. This preliminary conditioning of the catalyst ensures that when the engine does shut down for fuel economy, the catalyst remains effective for emission control, thus resolving the contradiction between fuel savings and emission control.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If the engine startup is disabled when the electric motor torque is sufficient, then the fuel consumption is reduced, but the catalyst warming capability is compromised

Engineering Contradiction:

Improvefuel consumptionVSAvoidcatalyst temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The system uses the electric motor's sufficient torque capability to meet vehicle propulsion needs without engine assistance, allowing the engine to remain shut down. The catalyst temperature is monitored and maintained through this selective engine-off strategy, demonstrating that the system can self-regulate to maintain catalyst temperature while minimizing fuel consumption by relying on electric motor power when sufficient.

Inventive Principle:

Principle #25Self-service

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 solution enhances fuel efficiency by minimizing unnecessary engine startups and maintaining catalyst temperature, thereby improving fuel economy and emission control by ensuring the catalyst operates efficiently above the light-off temperature only when required.

Implementation Method 1

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The catalyst temperature may be increased using various methods. For example only, heat from the exhaust gas expelled from the engine may increase the catalyst temperature. The exhaust gas transfers heat to the catalyst via convection, thereby increasing the catalyst temperature.

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

Fueling to the engine may also be adjusted to increase the catalyst temperature. For example only, unburned HC resulting from combustion may enter the catalyst where the HC oxidizes and increases the catalyst temperature.

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS9458812B2Engine control systems and methods for minimizing fuel consumption

Publication Date: 2016.10.04 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An engine control system comprises a temperature control module and an engine disabling module. The temperature control module regulates a first temperature of an electrically heated catalyst (EHC) based on a first predetermined light-off temperature while an engine is shut down. The engine disabling module selectively disables start up of the engine when a second temperature of a passive catalyst is less than a second predetermined light-off temperature while a maximum torque output of an electric motor is greater than a desired torque output.