Hybrid Starter Generator Load Control for SCR Catalyst Heating

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Solution Overview

Problem

The selective catalytic reduction (SCR) catalyst in vehicles struggles to effectively remove nitrogen oxide at low temperatures and excessively decomposes it at high temperatures, leading to inefficient emission control during cold starts, which affects fuel efficiency and emission regulations.

Innovation Solution

A vehicle control system and method that includes a hybrid starter/generator (HSG) to increase its load when the engine is idle at cold start, assisting engine torque and injecting a reducing agent to the exhaust gas when necessary, to rapidly heat the SCR catalyst and improve nitrogen oxide purification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the SCR catalyst operates at low temperature during cold start, then the engine can start quickly, but the nitrogen oxide cannot be effectively removed

Engineering Contradiction:

Improveengine start speedVSAvoidnitrogen oxide removal efficiency

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system pre-heats the SCR catalyst using the HSG motor before the engine starts. The controller activates the HSG motor to rotate the catalyst heater, generating heat in advance to raise the catalyst temperature to the effective working range (250-400°C) before nitrogen oxide treatment begins, ensuring both quick engine start and effective pollution removal.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the SCR catalyst operates at high temperature, then nitrogen oxide can be removed effectively, but the nitrogen oxide is excessively decomposed to discharge ammonia

Engineering Contradiction:

Improvenitrogen oxide removal efficiencyVSAvoidammonia discharge

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system employs temperature sensors to continuously monitor the SCR catalyst temperature and feeds this information back to the controller. Based on the real-time temperature data, the controller dynamically adjusts the HSG motor load and heater activation to maintain the catalyst temperature within the optimal range of 250-400°C, preventing both insufficient removal at low temperature and excessive decomposition at high temperature.

Inventive Principle:

Principle #23Feedback

3Loss of time

If the HSG load is increased during cold start idle state, then the SCR catalyst heating time is shortened, but the fuel consumption increases

Engineering Contradiction:

ImproveSCR catalyst heating timeVSAvoidfuel consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

The system uses periodic control of the HSG motor load during cold start. The controller activates the HSG motor at specific intervals and adjusts its load dynamically based on the current catalyst temperature. This periodic action pattern allows the system to heat the catalyst efficiently without maintaining maximum load continuously, thereby reducing overall fuel consumption while still achieving rapid heating.

Inventive Principle:

Principle #19Periodic action

4Reliability

If the SCR catalyst is heated rapidly during cold start, then the nitrogen oxide purification is enhanced, but the engine heating time is extended

Engineering Contradiction:

Improvenitrogen oxide purification efficiencyVSAvoidengine heating time

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The HSG motor serves multiple functions: it acts as both a starter motor for engine ignition and a drive motor for the SCR catalyst heater. By utilizing the same motor for both starting and heating functions, the system avoids the need for separate heating mechanisms that would extend engine heating time. The HSG motor efficiently performs both tasks within a unified operational framework.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 shortens the engine heating time, enhances nitrogen oxide purification, and improves fuel efficiency by assisting engine torque using the HSG, especially during cold starts when the SCR catalyst temperature is low.

Implementation Method 1

a hybrid starter/generator (HSG) configured to start the engine or generate electricity using energy generated in the engine

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an injection module which is mounted in the exhaust pipe and injects a reducing agent to the exhaust gas

Methodology Applied

Scientific EffectFluid injection: Injector

Implementation Method 3

a selective catalytic reduction (SCR) catalyst which is mounted in the exhaust pipe at a rear end of the injection module and reduces nitrogen oxide contained in the exhaust gas using the reducing agent

Methodology Applied

Scientific EffectSelective catalytic reduction: Catalysis

Data Source

PatentUS10787164B2System and method of controlling vehicle in cold start

Publication Date: 2020.09.29 HYUNDAI MOTOR CO LTD

AI summary

A method for controlling a hybrid vehicle for a cold start. The method includes determining whether a combustion engine of the vehicle is idling. The method further includes, when the engine is idling, increasing a load of a hybrid starter/generator (HSG) until a selective catalytic reduction (SCR) catalyst reaches a desirable temperature.