Engine Start Emissions Reduction via Pre-heated Catalyst
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Solution Overview
Problem
Vehicle emissions are higher during cold start conditions, and existing technologies struggle to efficiently reduce emissions at this time due to inefficiencies in the aftertreatment system.
Innovation Solution
Activating an electrically heated catalyst and opening an exhaust gas recirculation (EGR) valve before engine start to increase the temperature of aftertreatment devices, allowing for compound heating of air to enhance emissions conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine is cold started, then the engine can be started in cold conditions, but emissions levels are higher and aftertreatment system efficiency is reduced
Solution Approach 1:
The system performs preliminary heating of the aftertreatment devices and pre-conditioning of the air-fuel mixture before engine start. The EGR valve is opened and electrically heated catalyst is activated during the cranking phase, preparing the exhaust system to immediately process emissions upon engine ignition, thereby reducing cold start emissions without delaying engine startup.
2Productivity
If the aftertreatment system is activated before engine start, then emissions conversion efficiency is improved, but system complexity increases
Solution Approach 1:
The EGR valve and electrically heated catalyst serve dual functions: they are used during normal engine operation for emissions control and are also activated during cold start to pre-heat the aftertreatment system. This multi-functionality allows the system to achieve improved emissions conversion efficiency without adding dedicated cold start heating components, thereby limiting the increase in system complexity.
3Object-generated harmful factors
If compound heating is applied to increase aftertreatment device temperature, then emissions reduction is improved, but energy consumption increases
Solution Approach 1:
The system uses the engine's own cranking energy and residual heat to drive the compound heating process. The EGR valve recirculates exhaust gases that contain residual thermal energy, and the electrically heated catalyst uses minimal electrical power during the cranking phase. This self-service approach provides compound heating to reduce emissions without requiring substantial external energy input that would significantly increase overall energy consumption.
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 method reduces vehicle emissions during cold start conditions by pre-heating aftertreatment devices, improving their efficiency and maintaining drivability without degrading it.
Implementation Method 1
activating an electrically heated catalyst
Implementation Method 2
compound heat air circulated in an engine and engine exhaust after treatment devices
Implementation Method 3
temperatures of the after treatment devices increase at a higher rate
Data Source
AI summary
Methods and systems for operating an engine with an electrically heated catalyst and an electrically driven compressor are described. In one example, the electrically driven compressor and the electrically heated catalyst are activated before an engine start so that vehicle emissions may be reduced more efficiently at engine starting and thereafter.